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	England and Wales High Court (Patents Court) Decisions
You are here: BAILII >> Databases >> England and Wales High Court (Patents Court) Decisions >> Halliburton Energy Services, Inc. v Smith International (North Sea) Ltd & Ors [2005] EWHC 1623 (Pat) (21 July 2005) URL: http://www.bailii.org/ew/cases/EWHC/Patents/2005/1623.html Cite as: [2005] Info TLR 323, [2006] RPC 2, [2005] EWHC 1623 (Pat)

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IN THE HIGH COURT OF JUSTICE
CHANCERY DIVISION
PATENTS COURT

		Royal Courts of Justice Strand, London, WC2A 2LL
		21 July 2005

Mr Justice Pumfrey : Introduction

1. This is an action for infringement of two European Patents (UK) numbers 1 117 894 ('894) and 1 112 433 ('433). Both relate to drill bits for drilling in rock. '894 is in respect of an invention entitled 'Roller-cone bits, systems, drilling methods, and design methods with optimization of tooth orientation' and was referred to at trial as the Orientation patent. '433 is in respect of an invention entitled 'Roller cone drill bit, method of designing the same and rotary drilling system' and was called the Force Balancing patent at trial.
2. These proceedings started life in the County Court. The hearing before me, which lasted 13 days with substantial pre-reading, revealed that the subject matter of the patents was complex and more than justified the 15-day estimate that the trial ultimately received. The proceedings were not suitable for the County Court and should not have been started there.
3. The patents are interrelated. The Orientation patent contains three claims, each of which is to 'a method of designing a roller cone bit'. The Force Balancing patent contains claims to a 'method of designing a roller cone drill bit' (claims 1 to 5), three independent claims to drill bits having prescribed qualities in use (claims 6, 7 and 8) and a claim to the use of the bit. The allegedly infringing bits are designed using a complex computer program called the 'Integrated Dynamic Engineering and Analysis System' software, abbreviated to IDEAS, which may be considered to be a sophisticated simulation or modelling system. The input to the IDEAS system is a design of bit produced using CAD software. The performance of that design of bit under defined conditions in specified formation (type of rock) is simulated using IDEAS. The design is adjusted by the designer in response to the results of the simulation and again simulated.
4. The foregoing summary is enough to explain that apart from the usual questions of anticipation and obviousness this case raises a basic question relating to the inherent patentability of the alleged inventions. There is a serious attack on the sufficiency of the disclosure of both patents, to rebut which the patentee (to whom I shall refer as 'Halliburton') relies in part upon mutual cross-references and a cross reference to another document. All of this raises a difficulty of presentation of the issues in the case. Even at trial, there was no real agreement which patent should be taken first, the defendants ('Smith') putting the Orientation patent first but Halliburton starting off with the Force Balancing patent. In this judgment I shall deal with infringement and validity of each patent separately, taking the Force Balancing patent first.

The experts

5. Smith called Professor Newland, Emeritus Professor of Engineering in the University of Cambridge and holder of the 1875 Chair in Engineering from 1976 to 2003. He has wide engineering experience both practical and theoretical, but has no experience of drilling. His evidence was supported by that of Professor Cooper, a Professor at the University of California at Berkeley with wide experience of the engineering of drilling but little direct experience of bit design. His interest is principally in cutter materials. Halliburton called evidence from Mr James Hall, who had wide experience of drill bit design and manufacture with, among others, Hughes Tool. He had no experience of the design of computer simulations with which Professor Newland was familiar, and was, I think, less accustomed to expressing himself mathematically, with which the patents are very concerned. The experts should have been complementary in their knowledge, but, in fact there was little on which Mr Hall could agree with the others. Prof. Cooper was subjected to strong criticism on the ground of a lack of experience either in computer modelling or in drill bit design. Since he knew much about drilling generally I found his evidence helpful.

Background

6. Both patents are concerned with the design of roller cone drill bits, and in particular the type of bits used in vertical drilling for such purposes as oil and gas wells. Generally speaking, all such bits have three cones that rotate about their long axis. Each cone is provided with milled teeth integral with the cone or inserts made from tungsten carbide. The three cones are mounted on bearings and rotate about spindles fixed to three legs in such a way that the lower part of the side of the cone is generally in the plane of the hole bottom. The legs are welded together at their upper end which is provided with a threaded connection to which the drill string may be attached. I was provided with a number of bits in accordance with Smith's Notice of Models, which I examined to obtain a general impression of their construction. The transparent model is useful.
7. The parties made a serious attempt to put all the uncontroversial matter together with the material that it was agreed formed the relevant common general knowledge in a single copy report agreed by the experts. The result (a document showing extensive markup) is difficult to read and some of the alterations are trivial. Nevertheless, the cross-examination of Mr Hall showed that on the issues apparently in dispute his views were not substantially different from those advanced by Professor Cooper, with the important exception of Professor Cooper's views on the obviousness of balancing downforce as a matter of common general knowledge. Mr Hall was anxious to emphasise that some of the matters to which Professor Cooper referred were within the expertise of the driller in the field rather than a bit designer, but in the result these differences are immaterial. Accordingly, I shall rely on the common general knowledge part of Professor Cooper's report augmented by that of Mr Hall for the background. I will only summarise the principal points of relevance here.
8. A bit in use carries a very substantial weight, called the weight on bit, or WOB. This weight is made up of the drill collar and the rest of the drill string and is controlled by a tackle at the top of the string, which is supported by the derrick. Generally speaking there is a very easy introduction to the topic in the first chapter of the book called Rabia ('Oilwell Drilling Engineering: Principles and Practice' by Hussain Rabia), which is an undergraduate textbook located by Professor Cooper that is relied on as exemplifying the common general knowledge.
9. The manner in which the bit penetrates rock depends generally upon the geometry of the cones in the bit and the shape of the teeth. Rounded carbide inserts are used in hard rock: they break the rock by crushing it as the tooth rolls into contact with the formation. The forces employed are substantial: the weight on bit may be as high as 60 tonnes and the rate of rotation 60 rpm. Softer formations require (in different degrees, depending upon the other drilling variables) a combination of both a crushing and a scraping action, for which the inserts or milled teeth will be more chisel-shaped. To ensure a degree of scrape, the cones are positioned so that their axes of rotation are not radial of the longitudinal axis of the hole, but are slightly offset so as either to lead or to lag a purely rolling motion, like this:

10. The diagram shows a linear offset from the centre axis: obviously this can also be viewed as an angular offset from the radius of the bit. Whatever the precise orientation of the cones, the bit must be designed so that the rows of teeth each do their share of the work. It is helpful to think of the bit rotating and penetrating the formation: if a row of teeth follows the same path as another both will be doing less work. The following example is given by Professor Cooper, in which Ring A is cut by the heel or gage row of all three cones, ring B by cone 1, rings C and E by cone 2 and ring D by cone 3:

11. This diagram shows that the cones in a given bit are always different from each other. Each will be subjected to different dynamic conditions at the bottom of the hole, and there is no a priori reason to suppose that they will tend to wear evenly. The movement of the teeth is composed of a rolling about the cone axis and a translational component resulting in gouging and scraping, and is not easy to visualize. The force on the teeth in contact with the formation is itself the force which rotates the cones as the drill rotates.
12. The economics of drilling require that the bit be withdrawn from the hole as infrequently as reasonably possible. The rate of penetration needs to be as high as possible consistent with not causing premature wear of the bit, which obviously can destroy the advantage of a high rate of penetration if time is lost in early bit replacement. The process of 'tripping', which means the raising of the bit, is not trivial and is expensive—there may be thousands of feet of pipe to raise and uncouple. This means that durability of the drill is important and, with rate of penetration, is a primary concern of the user.^[1]
13. Both before and after the priority date, the task of the manufacturer of drill bits has been to achieve durability with a good rate of penetration. It is impossible to monitor conditions at the bottom of a hole and very difficult to emulate them at the surface and so a designer's job depended (and for those who do not use a simulation program, still depends) upon his ability to examine 'dull' (worn) bits and change the design in response to the pattern of wear he saw. Uneven patterns of wear in the teeth and in the cone bearings will indicate the unsuitability of a particular design for a particular formation, and it is important to appreciate that a bit that is wholly inappropriate for one combination of formation, WOB and RPM may be entirely suitable to different combination of conditions. Mr Hall had wide experience of bit design and he provided this description of dull bit analysis: '61. Analyzing the performance of previous bit designs and examination of these dull bits was the primary method of determining changes for a new bit design. Various conditions observed on dull bits would indicate improvements that could be made on a new design. …

62. For example, if a significant amount of breakage or chipping was consistently found in certain locations of the cutting structure of these dull bits, consideration would-be given to changing the number, shape or material used for the teeth in these locations. Adding rows of teeth to distribute the drilling forces may be considered. If this type of chipping or breakage was only found occasionally, the bit records for those bit runs. would be analyzed to determine if excessive WOB, excessive rotary speed or some other condition could have been the cause for the breakage. Consideration would also be given to the effects that changes to the tooth shape or quantity could have on the penetration rate of the bit. The experience and judgement of the bit designer would eventually be used to make changes to the design.

63. Another example would be if excessive wear was consistently noted in certain areas of the cutting structure, changes in the profile of the cone might be considered to decrease the amount of gouging and slicing that those teeth would experience. Again the effects that these changes would have on bit performance would be considered before changes would be made.

64. Unusual wear patterns observed on the bit would be considered in an attempt to determine possible causes for these conditions. Sharpening wear of the teeth on a bit can result from a condition known as "tracking". This condition is where as the cones rotate, one tooth falls into a crater on the bottom of the hole that has been caused by a previous tooth hitting at the same location. This condition causes a loss of penetration rate and results in wear to the cone shell as well as the teeth of the bit. Concentric rings worn into the cone shell can indicate that the bit is "running off-center" and is therefore not covering the bottom of the hole with cutting teeth in the desired locations as intended. This condition also results in decreased penetration rates and decreased bit life. Changes that would be considered to correct these conditions could include adding or removing. rows of teeth, changing the pitch scheme of teeth in the rows of teeth, changing the shape and length of teeth or other changes that a designers experience would indicate.'

14. The manner in which the wear on a dull bit is reported is systematized. Both Professor Cooper and Mr Hall produced versions of a grading system proposed by the International Association of Drilling Contractors and are agreed that this system would be known to the skilled bit designer. Professor Cooper produced a 'Bit Record' which shows the history of a number of bits in a particular well, with the 'Dull Cond[ition]' specified for each.
15. Accordingly, at the priority date drill bit design was in large part a matter for the skill, experience and intuition of the designer. Nobody has pointed to a comprehensive manual for drill bit designers, and I am sure that if one existed it would have been produced.
16. Both patents are addressed to persons wishing both to design and use simulation systems for drill bit design. Although the claims are directed to methods of design, and are hence the concern of a designer, the underlying equipment, if I can put it that way, is a simulation system that the patents say is new. The Force Balancing patent uses a 'Rock Bit computer model' for the purpose of working out the dynamics of a rotating bit and describes the design of a bit in terms of a 'general nonlinear optimisation problem with bounds and nonlinear constraints' applied to design variables, objectives expressed in terms of the design variables and the bounds on the design variables and the constraints on the system. The design process described in the Orientation patent involves the generation of both a display and numeric outputs showing the scraping motion of the teeth of a cone and necessarily involves the computation of the tooth and cone kinematics from the ratio of bit speed to cone speed: it is not on the face of it concerned with the actual interaction of bit and rock. Plainly, therefore, the specifications are addressed to (1) engineers who understand drilling and drill bits (2) engineers who understand simulations and their graphical display and (3) if not included among the others, engineers who can understand the mathematics of the interaction of a drill tooth and rock and design the software necessary to model the dynamics and kinematics of the bit. I return to this subject in more detail below.
17. Generally in considering these patents it is helpful to remember the distinction between cone kinematics, which describe the movement of the cone, and cone dynamics, which describe the forces on the cone that are responsible for the movement. As Professor Newland explained it, the kinematics are 'not in the ground. The kinematics is a theoretical exercise with the drill bit…another issue is the whole one of tooth to formation interaction.'

The Force Balancing patent

18. The introductory parts of both the Force Balancing patent and the Orientation patent are rather similar. There are seven parts of the background section of the Force Balancing specification, concerned with rotary drilling generally (paragraphs [0002]- [0004]), drill string oscillation (paragraphs [0005] and [0006]), optimal drilling with various formation types (paragraphs [0007]-[0010]), roller cone bit design (paragraphs [0011]-[0014]), tooth design ([0015]-[0015] and bottom hole analysis (paragraphs [0018]-[0022]).
19. The patent begins with a summary of the invention in paragraph [0001]:

'[0001] The present invention relates to down-hole drilling and especially to the optimisation of drill bit parameters. In particular it relates to a roller cone drill bit, a method of designing the same, and a rotary drilling system.'

20. Paragraphs [0002]-[0004] set out very general background material, all of which I have covered in my discussion of the background above. The section on drill string oscillation is common general knowledge. Reduction of such oscillations is claimed as an advantage of drill bits designed according to the invention (paragraph [0034]), but it is not otherwise referred to in the specification. The likely sources of oscillation formed a component of Smith's argument of obviousness, where I shall discuss it.
21. The section concerned with Optimal Drilling with Various Formation Types (paragraphs [0007]-[0010]) is largely the same as the section concerned with 'Rock Mechanics and Formations' in the Orientation patent. It is all common general knowledge. Set out in summary form are the factors affecting how a formation is drilled and the types of bit suitable for soft formation (long teeth, high gouge), hard formation (short rounded teeth, no gouge) and medium formation (between the two).
22. The next background section, 'Roller Cone Bit Design' is the same as the corresponding part of the Orientation patent, and was accepted by Mr Hall to be common general knowledge at the priority date. Its significance is greater in the Orientation patent, but I should refer to paragraphs [0011] and [0014]. Paragraph [0011] is concerned with the shape of the cones. It is pointed out that they need not be perfectly conical or frustroconical but may have what is called a 'swollen', that is bulging, axial profile. Apart from the shape of the cone itself, it is pointed out that both the angle between the axis of the cone and the radius of the bit (the offset angle) and the angle between the axis of the cone and the plane of the bottom of the hole (the journal angle, plainly related to the angle of the cone) are design parameters and affect the rolling of the cone, which, because it cannot necessarily roll true, causes gouging and scraping which, as is pointed out, is complex in nature.
23. Paragraph [0014] outlines the interrelationship of these design parameters and the effect of varying them. Two examples are given: cone angle and offset, which it is pointed out can be modified so as to increase or decrease the amount of bottom hole scraping. The other example is tooth length: 'Many other design parameters are limited in that an increase in one parameter may necessarily result in a decrease of another. For example, increases in tooth length may cause interference with the adjacent cones.'
24. Paragraphs [0015] to [0017] are concerned with tooth design. Although the other paragraphs just set out a summary of the common general knowledge in respect of the range of shapes of teeth and their relationship to the formation intended to be drilled, I should just refer briefly to paragraph [0017] because the shape of the tooth and its interaction with the formation is important.

'Chisel shaped inserts have opposing flats and a broad elongated crest resembling the teeth of a steel tooth bit. Chisel shaped inserts are used for drilling soft to medium formations The elongated crest of the chisel insert is normally oriented in alignment with the axis of cone rotation. Thus, unlike spherical and conical inserts the chisel insert may be directionally oriented about its center axis. (This is true of any tooth which is not axially symmetric.)The axial angle of orientation is measured from the plane intersecting the center of the cone and the center of the tooth.'

25. There is no doubt that oriented teeth were part of the common general knowledge of the designer. The angle of orientation affects the interaction of tooth and formation, and hence the relative movement (both rotational and translational) of the cone as the bit rotates. The gouging motion represents a translational movement between the tooth and the hole bottom. The movement of the tooth in the formation between the moment the tooth enters the formation and the moment it leaves takes a time and covers a distance determined by the rotation of the cone as it skids round the bottom of the hole. In the absence of a gouging motion, it should be remembered that the tooth movement can be visualised as a rolling movement about the point of the tooth, a movement whose translational element is small. The movement of the tooth in the coordinates of the hole bottom is shown by Professor Newland in Figure 7 in his principal report, explained further at transcript 1047 line 22.
26. The final section on background, "Bottom Hole Analysis', sets the scene for the description of the invention. Paragraph [0018] does not call for much comment: it trivially points out that bit design affects rate of penetration, and that rate of penetration plays a 'significant role' in the economics of drilling a well.
27. Paragraph [0019] begins to approach the heart of the invention:

'[0019] It has long been desirable to predict the development of bottom hole patterns on the basis of the controllable geometric parameters used in drill bit design, and complex mathematical models can simulate bottom hole patterns to a limited extent. To accomplish this it is necessary to understand first, the relationship between the tooth and the rock, and second, the relationship between the design of the drill bit and the movement of the tooth in relation to the rock. It is also known that these mechanisms are interdependent.'

This passage acknowledges the existence of 'complex mathematical models' that simulate bottom hole patterns. The bottom hole pattern is the cutting pattern left by the teeth in the formation at the bottom of the hole as the bit, subject to the WOB, rotates. The passage points out that in order to simulate the bottom hole pattern two things must be known: the way in which the tooth interacts with the formation and second 'the relationship between the design of the drill bit and the movement of the tooth in relation to the rock'. The specification acknowledges that it is known that these mechanisms are interdependent, and it could not be otherwise, because the forces acting on a cone are made up of the forces transmitted by the leg of the bit and the drag caused by the passage of the teeth through the rock along a path constrained by the geometry of the bit as it rotates in the hole.

28. In pararaph [0020] the specification continues with a description of the work done on these two problems, that is, the way in which the tooth interacts with the formation and the relationship between bit design and the movement of the tooth in relation to the rock:

'[0020] To better understand these relationships. much work has been done to determine the amount of rock removed by a single tooth of a drill bit. As can be seen by the forgoing discussion, this is a complex problem. For many years it has been known that rock failure is complex, and results from the many stresses arising from the combined movements and actions of the tooth of a rock bit. (Sikarskie, et al, PENETRATION PROBLEMS IN ROCK MECHANICS, ASME Rock Mechanics Symposium. 1973). Subsequently. work was been done to develop quantitative relationships between bit design and tooth-formation interaction. This has been accomplished by calculating the vertical, radial and tangential movement of the teeth relative to the hole bottom to accurately represent the gouging and scraping action of the teeth on roller cone bits (Ma, A NEW WAY TO CHARACTERIZE THE GOUGING SCRAPING ACTION OF ROLLER CONE BITS Society of Petroleum Engineers No 19448, 1989)^[2] More recently computer programs have been developed which predict and simulate the bottom hole patterns developed by roller cone bits by combining the complex movement of the teeth with a model of formation failure (Ma THE COMPUTER SIMULATION OF THE INTERACTION BETWEEN THE ROLLER BIT AND ROCK Society of Petroleum Engineers No 29922, 1995)^[3]. Such formation failure models include a ductile model for removing the formation occupied by the tooth during its movement across the bottom of the hole and a fragile breakage model to represent the surrounding breakage.

[0021] Currently roller cone bit designs remain the result of generations of modifications made to original designs. The modifications are based on years of experience in evaluating bit run records and dull bit conditions. Since drill bits are run under harsh conditions, far from view, and to destruction it is often very difficult to determine the cause of the failure of a bit. Roller cone bits are often disassembled in manufacturers' laboratories, but most often this process is in response to a customer's complaint regarding the product, when a verification of the materials is required. Engineers will visit the lab and attempt to perform a forensic analysis of the remains of a rock bit but with few exceptions there is generally little evidence to support their conclusions as to which component failed first and why. Since rock bits are run on different drilling rigs in different formations under different operating conditions it is extremely difficult [to] draw conclusion[s] from the dull conditions of the bits. As a result, evaluating dull bit conditions, their cause and determining design solutions is a very subjective process. What is known is that when the cutting structure or bearing system of a drill bit fails prematurely it can have a serious detrimental effect of the economics of drilling.'

29. The two paragraphs appear to recognise both that numerical techniques exist to permit the prediction and simulation of bit action on formation by combining the movement of the teeth with a model of how the formation fails under the action of the teeth, and that these techniques have been incorporated in the computer program referred to in the Ma Paper. It is suggested that what is lacking is a way of using these techniques to replace the methods of design from bit analysis described in paragraph [0021] and that this is described in paragraph [0022]: '[0022] Though numerical methods are now available to model the bottom hole pattern produced by a roller cone bit there is no suggestion as to how this should be used to improve the design of the bits other than to predict the presence of obvious problems such as tracking. For example the best solution available for dealing with the problems of lateral vibration is a recommendation that roller cone bits should be run at low to moderate rotary speeds when drilling medium to hard formations to control bit vibrations and prolong life, and to use downhole vibration sensors. (Dykstra, et al; EXPERIMENTAL EVALUATIONS OF DRILL STRING DYNAMICS Amoco report Number F94-P-80 1994).'
30. This passage seems to me to carry on the discussion in paragraph [0020] of the Ma paper, which is concerned with the modelling of the bottom hole pattern, and it is dismissive in tone, suggesting that Ma's program can be used only to predict the presence of obvious problems such as tracking. Halliburton contend that the disclosure of the Ma paper, which is rather more comprehensive than paragraphs [0020] and [0022] suggest, is incorporated by reference. The words used are not, in my judgment, capable of incorporating this disclosure into the disclosure of the patent. Patent specifications should be complete in themselves and while they must be read like any other document these words do no more than dismiss the Ma paper (and the other citations) as ineffective components of the state of the art.
31. Four so-called consistory clauses follow. These merely set out the four independent claims, paragraph [0024] corresponding to claim 1, paragraph [0025] to claim 3, paragraph [0026] to claim 6 and paragraph [0027] to claim 7. Less time was spent before me on claims 1 and 7 (the so-called volume claims) attention being concentrated on the 'force' claims 3 and 6.
32. Evidently the structure of claims 1 and 3 is identical. Each adopts a particular criterion for the design of the bit. Claim 1 is concerned with what can be called swept volume: at least one of the geometric design parameters must be adjusted until a calculation of the volume of rock cut by the teeth on each cone (cutting structure) shows that the volumes cut are equal for each cone. Feature (e) shows the recursive nature of the process. An adjustment is made: the performance of the bit is simulated: a further adjustment is made so as to reduce the differences between the volumes cut by each cone and the process is continued until those volumes are equal. Claim 3 calls for an entirely similar process, in which the criterion is an equality of the 'axial force' acting on each cone. (There is a serious dispute as to the meaning of 'axial' here which I shall postpone until I have considered the preferred embodiment, together with the claims to the actual products, claims 6 and 7.)
33. On the assumption that swept volume or axial force (the only two characteristics of the bit in use mentioned in the claims) are sensitive to one or more of the geometric design parameters, one can turn to the description of the preferred embodiment to see the manner in which it is proposed that this should be achieved.

Force balanced Roller-Cone bits

34. At paragraph [0028] the patent introduces the embodiments to be described with a statement that in those embodiments

'the roller cone bit designs should have substantially equal mechanical downforce on each of the cones. This is not trivial: without special design consideration, the weight on bit will NOT automatically be equalised among the cones.'

35. Three causes of lack of balance are identified in paragraphs [0029]-[0031]. These are respectively (a) asymmetric cutting structures (cones) (b) offset effects and (c) tracking effects. The cones are asymmetric because the teeth (apart from the gage row) are in different places on each cone and are different in number. The gouging and scraping effect of the cone offset (paragraph 10 above) is different from row to row between the cones. Finally, a cone that tracks one of the others will have the effect that at least one cone will be cutting more formation than the other two and the bit is out of balance.
36. Paragraph [0032] suggests that substantially equalising the downforce per cone is very important and that this has been discovered by the patentee. Curiously, the words 'and greatly underestimated' are added to this assertion of importance, words that in a well-drafted document would tend to suggest that the patentee was here acknowledging that equal downforce on the cones had been recognised as at least one criterion even though its full importance had not been recognised. But this document is so poorly expressed that I am not willing to regard this phrase even as a straw in the wind. The paragraph promises that the application describes bit design procedures that provide optimization of downforce balancing 'as well as other parameters'.
37. The principal advantage of equalising the downforce on the cones is said to lie in the reduction of vibration. Out-of-balance forces parallel to the axis of the hole will create a bending moment rotating about an axis perpendicular to the axis of the hole. This moment may be capable of coupling to the various oscillations of the drill string (paragraph [0034]), so contributing to instability and to uneven wear. The reduction in vibration lies at the root of the improvements in wear performance set out in paragraph [0035]. The improvements for the designer follow from the criterion adopted (equal axial force or equal swept volume) and the use of a simulation system.
38. Paragraph [0037] contains a cross-reference to the application for the US equivalent to the Orientation patent. There is a dispute (based on the non-availability of the US application at the application date and the publication date of this patent) about the effectiveness of this cross-reference for any purpose. I shall discuss this passage below (paragraph 58).

The Addressee of the specification

39. Before I consider the preferred embodiment, it is helpful to consider in rather more detail the qualities of the person through whose eyes the specification is to be read. I have already identified the relevant skills in general terms. The 'notional skilled person' who is the addressee of the specification has been described in various ways for various purposes. The skilled person is essentially a legal construct, and not a mere lowest common denominator of all the persons engaged in the art at a particular time. In some cases, of which this is an example, it is clear that the specification is addressed to sets of skills that in the real world would be possessed by more than one person, and such a specification can be said to be addressed to a team.
40. There is no doubt that in the present case the team has at least two components. The first is the drill bit designer. Halliburton's witness Mr Hall was an example of a highly qualified real-world drill bit designer. It was accepted that a graduate engineer with three years' experience (or perhaps a non-graduate of 10 years' experience) was suitable. I think that it is not right to suggest that the specification is addressed to experienced autodidacts in a particular industry: after all, it should be usable by recent entrants. But although principles of bit design are on the evidence taught in universities, experience is also essential in what was at the priority date a largely empirical activity. But this specification calls for somebody who can carry out the computations called for by the claim. So the skilled person needs to be skilled in numerical methods in engineering computation and modelling. Professor Newland, who was too vastly skilled in this area to be representative, had the considerable advantage that he was a very experienced teacher of engineers at Cambridge and had a good idea of the skills of such persons, and he provided the guidance on this aspect of the skillset of the notional addressee in this regard. He tended to relate the relevant skills of the computer modeller, who is confronted with the three tasks of computing the kinematics and dynamics of the bit and displaying the results, with graduates studying for a master's degree who might be thought to be on the lower end of the spectrum of persons available to fulfil complex simulation tasks.
41. As it happened, IDEAS, the program alleged to infringe, was very visual. It displayed simulated pictures of (for example) the bottom of a hole, or of a tooth showing the total interference with the formation caused by any specified row of inserts on a cone. But most of the screens were comparatively simple graphical depictions of the results of many calculations —see for example the Force History plots in Smith's Amended Product and Process Description (the PPD). No doubt the addressee will have access to computer programmers, themselves of high skill, capable of putting the results into a usable visual form, but that is not what this invention is about.
42. In this connection, I should mention that although Smith's program had been heavily analysed, there was no evidence as to what, if any, use of the invention had been made by Halliburton and no evidence as to the constituent members of any team. Indeed, there was no evidence that Halliburton had any working computing programs for bit design.

The Rock Bit Computer Model

43. Within this judgment I cannot give a discussion of coordinate systems and of transformations between them. This aspect of geometry at the fairly elementary level would , I think, form part of the common general knowledge attributable to the skilled person. The writer of the specification is not always careful to distinguish between a force (a quantity having both magnitude and direction), the magnitude of a force regardless of the force's direction, the components of a force (forces in predetermined directions whose sum is equal to the force under consideration) and the magnitudes of the components of the force. It is normal usage to agree upon a direction of particular interest, (the axis of a cone, say, or the axis of the drill string) and relate all relevant forces to that direction. The use of directional subscripts x, y and z strongly indicates that components are under consideration. Z is conventionally used for the principal axis of rotation of a body, and this convention seems to be observed.
44. The skilled person realises that a drill bit rotating in rock under a weight on bit of thousands of kilograms is a very complex system. A force which is along the axis of rotation of the bit does not affect rotation. A force acting on the bit that is parallel to the axis of rotation of the bit, but displaced from it, will create a moment that tends to bend the bit away from its intended path and will no doubt rotate with the bit. A force at right angles to the bit axis will have the same effect. The skilled reader of the specification will have a mental picture of the forces acting on the bit. I do not mean to suggest that this mental picture will be anything other than qualitative. Mr Hall was at pains to point out that at the priority date the skilled bit designer based his designs upon the appearance of dull bits, not upon an estimate of out-of-balance forces. While the skilled person would realise that the uneven wear was the result of forces that were unequal, Mr Hall described the approach thus:^[4]

'3 Q. Does it not therefore follow that the bit designer would be

4 aiming to design his bit, at least one of his objectives in

5 designing his bit, would be to ensure that the loads acting on

6 these bearings, as between the cones, were the same or as

7 close to the same as he could manage?

8 A. Again, running the risk with, and all due respect, loads

9 per se in the act of bit design really are not considered

10 implicitly. They are by moving [compacts] around, by deciding

11 how many cutting teeth to put on a cone, whatever. He would

12 know that he is effecting the way in which the cone would be

13 loaded, but loads per se had not been a part of bit design.

14 They are just not known, so they were not really considered.

15 Wear was the element that actually drove design modifications.'

45. What Mr Hall is describing was the process of designing starting with a dull-bit analysis. I take it from this (none of the other expert witnesses had design experience) that the skilled person is not used to considering wear on a bit in terms of unbalanced forces, but in terms of the alterations which he can make which will, Mr Hall accepted, result in an improved balance.
46. The description of the preferred embodiment starts with the description of the Rock Bit computer model. As logic might suggest, the model starts with the single tooth in paragraph [0040]. Figure 1 and the discussion in paragraph [0040] are intended to show how the force acting on a single tooth may be analysed by decomposing the tooth into individual elements of square cross section, each with three force components acting on them. The mathematics indicates what the inventor considers the forces to depend upon. There are three expressions, for the three components of the force upon a tooth element:

47. The first of these equations states that the force along the z-axis of the element (Fze) is made to depend on the compressive strength s, the area normal to the z-axis Se, and ke, which is said rather vaguely to be 'a coefficient associated with the formation [rock] properties'. The inevitable inference is that an element is generally shaped like a matchstick. The second and third equations state that the x- and y- components of the force (the lateral components of the force) have a form rather like the forms of the expressions for sliding or static frictional forces, a resemblance which is reinforced by using µ as the coefficient. The force along the z-axis is proportional to penetration and thus to volume displaced.
48. The suggestion is that the total force on the tooth can be ascertained by integrating these equations. This means (in essence) summing all the components of forces over all the elements into which the tooth has been decomposed so giving the x, y and z components of the total force F^[5]. It is an entirely standard technique. The suggestion is that the coefficients k and µ can be ascertained by a lab test on samples of rock, and the advantage of using this technique is that the lab test need only be done once for a given formation. Different shapes of tooth can be accommodated in the mathematical process of integration by defining the shape of the elements appropriately but assuming that a matchstick element always experiences a force that may be expressed in the same way, as a product of two coefficients and the cross-sectional area of the matchstick.
49. The difficulty here is that this is a general description of the technique, supposedly adequate to accommodate bits in which there is substantial offset and its associated gouging action. As paragraph [0041] explains:

'After having the single element force model the next step is to determine the interaction between inserts and the formation drilled. This step involves the determination of the tooth kinematics (local) from the bit and cone kinematics (global) as described bellow

(1) The bit kinematics is described by bit rotation speed O=RPM (revolutions per minute), and the rate of penetration, ROP. Both RPM and ROP may be considered as constant or as function with time.

(2) The cone kinematics is described by cone rotational speed. Each cone may have its own speed. The initial value is calculated from the bit geometric parameters or just estimated from experiment. In the calculation the cone speed may be changed based on the torque acting on the cone.

(3) At the initial time, t0, the hole bottom is considered as a plane and is meshed into small grids The tooth is also meshed into grids (single elements). At any time t, the position of a tooth in space is fully determined. If the tooth is in interaction with the hole bottom, the hole bottom is updated and the cutting depth for each cutting element is calculated and the forces acting on the elements are obtained.

(4) The element forces are integrated into tooth forces, the tooth forces are integrated into cone forces, the cone forces are transferred into bearing forces and the bearing forces are integrated into bit forces.

(5) After the bit is fully drilled into the rock, these forces are recorded at each time step. A period time, usually at least 10 seconds, is simulated. The average forces may be considered as static forces and are used for evaluation of the balance condition of the cutting structure.'

50. It is the rotation of the bit that drives the cones whose teeth engage with the formation by rotating while being driven into it by the WOB, and remove material by crushing and gouging. The actual rotation of the cones is thus determined (1) by the speed of rotation of the bit and (2) the effects of the interaction of the teeth and the formation which will produce a torque acting on the cone. The essential quantity is called the cone-bit speed ratio. The cone-bit speed ratio plays an important role in the Orientation patent and much of the evidence relating to it was given while that patent was under consideration.
51. Professor Newland was of the firm opinion that the three equations for the components of the force acting on a tooth element were each flawed. Although this is likely to be true what is being described is a simulation and will necessarily involve simplifying assumptions. The main problem with these two paragraphs of the specification, to which I shall return below when I consider insufficiency, is that it is accepted that the specification contains no information about how to (1) calculate the position of a given tooth in a formation as the bit rotates (2) how to calculate the forces on the tooth for each tooth in contact with the formation, and (3) how to integrate the forces so calculated to be acting on the tooth into bearing forces and bit forces.
52. It is also to be noted that the patent gives no guidance as to how to calculate changes to the cone speed 'based on the torque acting on the cone'. This calculation is not called for by the claim. I do not think that the phrase 'cone speed may be changed…' could be permissive rather than an essential aspect of any model of a rotating drill bit. In paragraphs 215-220 of his principal report, Professor Newland explains his reasons for saying that the disclosure of the specification did not extend to this calculation, and he agreed in cross-examination that he considered that the specification contemplated that a simulation would inevitably involve an adjustment of the cone-bit speed ratio. I deal with this question when I consider the sufficiency of the disclosure.
53. The specification next discusses the evaluation of a force-balanced roller cone bit. Paragraph [0042] discusses the balance condition of a bit with regard to three criteria, identified by reference to Figure 2. Each criterion expressed in equations (4), (5) and (6) is expressed as a maximum difference in a specified quantity between the cones. The selected criteria are (equation (4)) percentage resolved weight on cone (i.e. proportion of the WOB borne by each cone) (equation (5)) percentage resolved cone axial force and (equation (6)) percentage resolved cone moment in the direction perpendicular to the cone axis. The final criterion expressed in equation (7) concerns the radial component of the bit imbalance force whose effect is described in paragraph [0034] (see also paragraph 37 above).
54. Paragraph [0042] then sets out at some length the statement that for perfect balance each of the selected quantities must be equal between cones, and the radial component of the bit imbalance force should be zero. That is all this passage says, and it adds nothing to the disclosure save to say that control of the selected quantities within some limitations will be sufficient.
55. One of the questions in the case is what the claim means when it refers to the 'axial force acting on each cutting structure'. Paragraph [0042] supplies the greater part of the context. The cutting structure is without doubt the cone, and the candidates for the relevant force are the WOBi, the vertical force described as the proportion of the weight on bit taken by cone i, and the Fzi, which is the proportionate 'i-th cone axial force', that is, the component of the force acting on the cone acting along the cone's axis of rotation. The latter is shown clearly in Figure 2. It should be noted that Fr is likely to be heavily influenced by an imbalance in the Fzi, the greater the imbalance the greater the net out of balance force on the bit.
56. Paragraph [0043] describes how the force balancing criteria described in paragraph [0042] are related to energy balancing criteria. Energy balancing is much easier to understand since the specification adopts as its energy balance criterion the single requirement that the volume of formation removed by each cone per revolution should be the same (see equation (11) in paragraph [0048]). This is the method of claim 1, which is not alleged to be infringed.

'[0043] There is a distinction between force balancing techniques and energy balancing. A force balanced bit uses multiple objective optimization technology, which considers weight on bit, axial force and cone moment as separate optimization objectives. Energy balancing uses only single objective optimization as defined in equation (11) below.'

57. The specification turns to the design of a bit in paragraph [0044] and the following paragraphs. This description is entirely in terms of volume or energy balancing, it being stated in paragraph [0046] that the inventor has found that an energy balanced bit 'will lead to force balanced in most cases'. A series of steps are described:

(a) Selection of design variables. In the simplified example given by reference to Figure 3, these are tooth-related, the cone profile, offset and journal angle being assumed to be invariant. The design variables are the radial position of the tooth, the length of the crest and the tooth angles.

(b) Definition of objectives, and expression of objectives as function of design variables. In the example given, the objective selected is to let each cone remove the same amount of rock in one revolution of the bit. It appears to be assumed that the bit has a specified cutting depth per revolution (it is called ., and is never referred to again in the specification). It is then stated that

'It is not difficult to calculate the volume removed by each row, and the volume matrix may have the form



This expression is vacuous: it states that there exists a matrix V which describes the amount of rock removed per row of teeth (the index j) and per cone (the index i). So far as the patent is concerned, all the Vij are to be calculated as functions of the design variables. There is no disclosure in this document of a method (an algorithm, an analytic expression or whatever) for doing this. The matrix V is not the end of the matter, because it is recognised that the matrix calculated in a 2-D manner, which I assume means on the assumption of a cone rolling about a radius with no offset, must be further modified by a scale matrix, the elements of which reflect the number of teeth and the tracking condition. I quote paragraph [0047]:

'In reality the removed volume by each row depends not only on the above design variables, but also on the number of teeth on that row and the tracking condition. Therefore the volume matrix calculated in a 2D manner must be scaled. The scale matrix, KV may be obtained as follows.



where V_3d0 is the volume matrix of the initial designed bit (before optimization). V_2d0 is obtained from the rock bit computer program by simulate the bit drilling procedure at least 10 seconds [sic]. V_2d0 is the volume matrix associated with the initial designed matrix and obtained using the 2D manner based on the bottom pattern shown in Figure 4. The volume matrix has the final form



In fact, equations (9) and (10) are the same. Equation (10) repeats the information that the matrix is a function of the four variables identified in paragraph [0045], that is the selected design variables. Paragraph [0046] told us that the elements Vij of the matrix V are functions of the design variables. The actual objective is identified finally in paragraph [0048], which is to minimise the root mean square deviation in volume removal between the cones.

(c) Define the bounds of the design variables and the constraints. This stage is described in paragraphs [0049]-[0051]. Examples are given (minimum tooth crest length, for example) and it is emphasised that it is particularly important to avoid interference between teeth on different cones during rotation, and to specify the width of the uncut rings on the hole bottom. Further expressions are given which merely repeat what is said in words (equations (12) and (13)). These are purely geometrical constraints.

(d) Solution of the problem. Paragraph [0052] describes how to carry out the optimization of the design.

'[0052] After having the objective function, the bounds and the constraints. the problem is simplified to a general nonlinear optimization problem with bounds and nonlinear constraints which can be solved by different methods. Figure 6 shows the flowchart of the optimization procedure. The procedure begins by reading the bit geometry and other operational parameters. The forces on the teeth, cones: bearings, and bit are then calculated. Once the forces are known, they are compared, and if they are balanced, then the design is optimized. If the forces are not balanced, then the optimization must occur. Objectives, constraints. design variables and their bounds (maximum and minimum allowed values) are defined, and the variables are altered to conform to the new objectives. Once the new objectives are met. the new geometric parameters are used to re-design the bit, and the forces are again calculated and checked for balance. This process is repeated until the desired force balance is achieved.'

It is worth observing that the whole of the description of the preferred embodiment, this passage apart, is concerned with volume balancing, as paragraph [0054] makes clear. That paragraph explicitly states that once volumes are equalized, force balancing is also achieved. This is inconsistent with paragraph [0043] and slightly inconsistent with paragraph [0046], where it said to happen 'in most cases'. I do not think this particularly matters.

The relevance of the Orientation patent to the Force-balancing patent

58. Generally speaking, the specification of the Force Balancing patent is remarkable for the small amount of information it gives on how actually to perform the volume calculations and the force calculations which are called for by the claims. The expressions actually given are entirely trite and add nothing to the verbal disclosure, merely repeating it in a somewhat more compact form. This has led to a wide-ranging allegation of insufficiency, which has in turn led to a suggestion by Halliburton that the disclosure of the specification could for all purposes be taken to include the disclosure of the Orientation patent and also of the Ma paper, which it was not contended was common general knowledge but was said to be incorporated by the combined effect of paragraphs [0020] and [0022]. I shall deal with the disclosure of the Ma paper below. I am satisfied that there is no question here of incorporation of the disclosure of the Orientation patent by reference for two reasons. First, for the reason I have given in paragraph 38 above, the words of paragraph [0037] do not direct the skilled man to

'US Patent Application 09/387,304 filed 31 August 1999' if he wants any information about how to implement a bit design system according to this invention. I quote the passage: 'U.S. Patent Application 09/387.304, filed 31 August 1999 (issued as US patent 6.095,262), entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimization of Tooth Orientation" (Atty. Docket No. SC-98- 26), and claiming priority from U.S. Provisional Application 60/098.442 filed 31 August 1998, describes roller cone drill bit design methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application.'

Let me take an example. If the designer is interested in force-balanced bits with conical inserts, whose cutting effect does not depend upon orientation, why, one might ask, should he look at this specification at all? There is no direction to consult the specification with a view to obtaining further information on the modelling techniques called for by the claim. I do not think it is legitimate as a matter of interpretation to take a passage such as that above and build out of it a suggestion that if the skilled person is at a loss as to how to proceed, the solution to his problem is, or may be, available in the cited publication. For this reason, the disclosure of the Orientation patent is not part of the disclosure of this patent, and I can interpret the claims without regard to it.

59. The second reason is that I am of the view that the application for the Orientation patent cannot, in the somewhat unusual circumstances of this case, be a legitimate cross-reference in any event. This conclusion is an alternative reason for my decision to take no account of the Orientation patent and may be of some practical importance to those who file patent applications at the EPO. I set out the steps of the reasoning in Annex A below in order to avoid disrupting this discussion.
60. The reference to the Ma paper is summarised in paragraph 29 above. As a matter of construction, this is the thinnest possible basis for a suggestion that the disclosure of the paper is to be incorporated in the patent. It seems to me that the specification does not point the addressee in the direction of the Ma paper for the purpose of supplementing its disclosure for any purpose. It is a description of the background prior art. I think that the Ma paper is really disclosed as a record of the existence of a computer program which does not do what the claim requires, in other words a failed proposal. If the patentee had wished to use the disclosure of Ma, the cross-reference should have been express.
61. In general, cross-referencing for the purpose of supplementing the disclosure is highly undesirable, and is not permitted by the EPO, which deals with the matter as follows in its Guidelines for examination Chapter C-II:

'4.18 Reference documents

References in European patent applications to other documents may relate either to the background art or to part of the disclosure of the invention.

Where the reference document relates to the background art, it may be in the application as originally filed or introduced at a later date (see II, 4.3 and 4.4).

Where the reference document relates directly to the disclosure of the invention (e.g. details of one of the components of a claimed apparatus), then the examiner should first consider whether knowing what is in the reference document is in fact essential for carrying out the invention as meant by Art. 83:

If not essential, the usual expression "which is hereby incorporated by reference", or any expression of the same kind, should be deleted from the description.

If matter in the document referred to is essential to satisfy the requirements of Art. 83, the examiner should require the deletion of the above-mentioned expression and that, instead, the matter is expressly incorporated into the description, because the patent specification should, regarding the essential features of the invention, be self-contained, i.e. capable of being understood without reference to any other document. One should also bear in mind that reference documents are not part of the text to be translated pursuant to Art. 65.'

62. I am not concerned with how an application is to be examined, but this principle is a sound one. If the disclosure is essential to the patent that fact should be made abundantly clear. As a matter of the ordinary principles of document construction it is not permissible to exclude the possibility of a cross-reference for essential material: but the court must, I think, be on its guard to ensure that the cross-reference is a proper one. This is not such a cross-reference.
63. Accordingly I must interpret the claims in their context in the specification, ignoring the cross-reference to Ma and to the optional features disclosed in the application for the Orientation patent.

The claims of the Force Balancing patent

64. It is convenient to deal with the method claims and the product claims separately. The two independent method claims, 1 and 3, are set out above but I repeat them for convenience:

Claim 1:

A method of designing a roller cone drill bit comprising a plurality of arms rotatable cutting structures mounted on respective ones of said arms and a plurality of teeth on each of said cutting structures, the method comprising the steps of

(a) calculating the volume of formation cut by each tooth on each cutting structure (16) of the roller cone drill bit (10);

(b) calculating the volume of formation cut by each cutting structure per revolution of the drill bit;

(c) comparing the volume of formation cut by each of said cutting structures with the volume of formation cut by all others of said cutting structures of the bit;

(d) adjusting at least one geometric parameter on the design of at least one of the culling structures; and

(e) repeating steps (a) through (d) until substantially the same volume of formation is cut by each of said cutting structures of said bit (10) when the drill bit is drilling into a formation.

Claim 3:

A method of designing a roller cone drill bit comprising a plurality of arms, rotatable cutting structures mounted on respective ones of said arms and a plurality of teeth on each of said cutting structures, the method comprising the steps of:

(a) calculating the axial force acting on each tooth (18) on each cutting structure (16) of the roller cone drill bit;

(b) calculating the axial force acting on each cutting structure per revolution of the drill bit;

(c) comparing the axial force acting on each of said cutting structures with the axial force on the other ones of said cutting structures of the bit;

(d) adjusting at least one geometric parameter on the design of at least one of said cutting structures; and

(e) repeating steps (a) through (d) until substantially the same axial force will act on each cutting structure when the drill bit (10) is drilling into a formation.

65. The claims raise two common points on construction, the meaning of the words 'repeating…until…' and of the concluding words 'when the drill bit (10) is drilling into a formation'. The second problem arises on claim 3 only, and that is to identify the axis referred to in the phrase 'axial force'.

Construction—when a drill bit is drilling into a formation

66. This phrase appears also in the product claims 6 and 7. In their context in claims 1 and 3, Smith submit that the words plainly refer to the process of simulation. Both of the method claims use the word 'cut' to refer to the material calculated to have been cut and it is submitted that to suggest that the reference is to a bit cutting in the real world cannot be supported. The reference is plainly, it is said, to the simulation of the cutting action of the bit in the simulated formation. This is not the end of the this matter, which needs further consideration when the designers' evidence of the way in which they use the IDEAS software is considered, in paragraph 114 below. I accept the main thrust of Smith's submission, and I do not understand Halliburton to dissent from it.
67. When one turns to the product claims, on the other hand, Smith contend that the words can only refer to the real world, and the formation referred to is real rock. Since the claims are not limited to bits made by simulation according to the method claims, it is said that there is no other way of interpreting this requirement. I consider this question below.

Construction: 'axial force'

68. These words appear in features (a), (b), (c) and (e) of claim 3. Halliburton say that the axis referred to is the axis of the drill string and the bit, i.e. the axis of the hole drilled: Smith say it is the axis of the cone. I have found it very difficult to decide between these possible constructions, the more so because the specification is far from clear or coherent. The principles to be applied are set out in Lord Hoffmann's speech in Kirin- Amgen v TKT [2004] UKHL 46, paragraphs 30-35. Given the approval that is given in that speech to the observations of Jacob LJ in Rockwater Ltd v Technip France SA [2004] EWCA Civ 381 I shall set out that useful list of applicable principles. I take the responsibility for modifying principles (e) and (f) slightly to take account of the single criticism that Lord Hoffmann makes of this list.

'(a) The first, overarching principle, is that contained in Art 69 itself. Sometimes I wonder whether people spend more time on the gloss to Art 69, the Protocol, than to the Article itself, even though it is the Article which is the main governing provision.

(b) Art 69 says that the extent of protection is determined by the terms of the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.

(c) It follows that the claims are to be construed purposively – the inventor's purpose being ascertained from the description and drawings.

(d) It further follows that the claims must not be construed as if they stood alone – the drawings and description only being used to resolve any ambiguity. The Protocol expressly eschews such a method of construction but to my mind that would be so without the Protocol. Purpose is vital to the construction of claims.

(e) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.

(f) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol – a mere guideline – is also ruled out by Art 69 itself. It is the terms of the claims which delineate the patentee's territory.

(g) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements. Hoffmann LJ put it this way in STEP v Empson [1993] RPC at 522:

"The well known principle that patent claims are given a purposive construction does not mean that an integer can be treated as struck out if it does not appear to make any difference to the inventive concept. It may have some other purpose buried in the prior art and even if this is not discernible, the patentee may have had some reason of his own for introducing it."

(h) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context. A good example of this is the Catnic case itself – "vertical" in context did not mean "geometrically vertical", it meant "vertical enough to do the job" (of supporting the upper horizontal plate). The so-called "Protocol questions" (those formulated by Hoffmann J in Improver v Remington [1990] FSR 181 at p.189) are of particular value when considering the difference of meaning between a word or phrase out of context and that word or phrase in context. At that point the first two Protocol questions come into play. But once one focuses on the word in context, the Protocol question approach does not resolve the ultimate question – what does the word or phrase actually mean, when construed purposively? That can only be done on the language used, read in context.

(i) It further follows that there is no general "doctrine of equivalents." Any student of patent law knows that various legal systems allow for such a concept, but that none of them can agree what it is or should be. Here is not the place to set forth the myriad versions of such a doctrine. For my part I do not think that Art. 69 itself allows for such a concept – it says the extent of protection shall be determined by the terms of the claims. And so far as I can understand, the French and German versions mean the same thing. Nor can I see how the Protocol can create any such doctrine.

(j) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.

(k) Finally purposive construction leads one to eschew what Lord Diplock in Catnic called (at p.243):

"the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge."

Pedantry and patents are incompatible. In Catnic the rejected "meticulous verbal analysis" was the argument that because the word "horizontal" was qualified by "substantially" whereas "vertical" was not, the latter must mean "geometrically vertical."'

69. I would diffidently add three observations of my own. The first is merely the trite principle that the addressee of the specification is the person skilled in the art, who approaches the document with the common general knowledge. Second, there may be obscurities and difficulties in a claim that cannot be resolved by an appeal to context. It is very rare that some sensible meaning cannot be attributed to the words used in a patent claim, but where a claim permits alternative interpretations it is possible to be left with no alternative but to take the most straightforward. Finally, and most importantly, over-meticulousness is not to be equated to carefulness. Care in working out what the patentee was aiming at when he chose the words he used is absolutely necessary.
70. Turning to claim 3, the context in which the claim is to be interpreted in this case may be summarised as follows.
71. Existing roller cone bits, designed incrementally from pre-existing bits, are generally not balanced (paragraph [0029]). The bits made using the invention should have substantially equal mechanical downforce on each of the cones, that is, the WOB will be equalized among the cones (paragraph [0028]) when in use. Substantially equalized downforce is a greatly underestimated factor in roller cone performance, in particular reducing gyration, and the patent describes bit design procedures which provide optimization of downforce balancing (paragraph [0032]). The improved performance of balanced-downforce cones may be partly due to the reduction in oscillation caused by reduction in bending moments (paragraph [0034]).
72. A bit should be made using the described Rock Bit Computer Model. The balance condition of a bit designed in this way may be evaluated using three criteria identified by reference to Figure 2: equalisation of the downforce on each bit (equation (4)) so that each cone carries about one-third of the total WOB; equalization of the cone axial forces (equation (5)); and equalization of the per-cone moments perpendicular to the cone axes (equation (6)). Generally speaking each of these variables has to be controlled within limits and if they are the bit will be balanced (concluding words of paragraph [0042]). All three will be equalized if volume of rock cut per bit revolution is equalized between the cones (paragraph [0046]).
73. This summary shows that the problem of identifying the axis referred to by the word 'axial' is caused by the patentee's use in the claim of exactly the same words to specify the force to be balanced as are used in paragraph [0042] of the specification to describe one only out of three (or four) quantities each of which needs to be equalized if (in the specification's terms) the balance condition is to be achieved. In paragraph [0042] other forces are described, one of which is the per-cone downforce, or WOB, which is of course the force that Halliburton says is being referred to by the claim. It therefore looks as though the draftsman has made a clear choice in the claim between the various forces that are candidates for balancing, albeit a choice that may be thought to be odd having regard to the importance attributed by the specification to the equalization of downforce in paragraphs [0028]-[0035], and has selected the coneaxial force. The impression that a deliberate choice has been made is only reinforced when it is remembered that each of the three variables, weight on bit, axial force and cone moment, are expressly described as 'separate optimization objectives' in paragraph [0043]. Claim 3 is thus a claim to equalizing one of the 'separate optimization objectives'. So construed in context, 'axial' refers to the cone axis.
74. A different approach to the problem is this. The volume balance that is the subject of claim 1 will, so far as the specification is concerned, achieve the overall balance that is desired and will when achieved include the balance in downforce. What then is the reason for claim 3? Why single out one criterion (cone axial force) nowhere discussed in detail distinctly from the other four criteria? The specification itself makes it clear in a lengthy passage that downforce balance is highly desirable, and no particular significance is attached to the other three quantities. Since the WOB is in fact an axial force, albeit along another axis not referred to in the specification or labelled in Figure 2, the context that matters for claim 3 is provided by paragraphs [0028] – [0035]. The use of terms for the WOB in the claim that are not used elsewhere in the specification and have been used in respect of another force described with reference to Figure 2 is certainly unfortunate but would not cause the skilled reader any difficulty.
75. Furthermore, the 'cone axis' construction does not solve a similar problem that arises with the first feature of the claim ('calculating the axial force acting on each tooth on each cutting structure…') which plainly refers to the axis of the tooth at this point in the claim. Figure 2 does show such forces labelled WOBi. Although they are labelled in a way that suggests that they represent the tooth's total fraction of the WOB, it is quite possible to view them as the axial components of WOB relative to tooth axis. These then are the components to be calculated using the Rock Bit Model, and it follows that 'axial' is referring to the drill bit axis.
76. Obviously there is something to be said for both interpretations. I approach the problem in this way.

(a) Given that the words 'cutting structure' undoubtedly mean 'cone', the literal meaning of the words 'calculating the axial force acting on each tooth on each cutting structure' at first sight indicates the axis of the tooth, principally because when the tooth is not in formation there is no force on it. Generally speaking, a force acting on the tooth will have a component along the tooth's major axis: this is what is shown as the WOBi in figure 2.

(b) The skilled reader would realise that the forces acting on the tooth varied very substantially as the cone rotated. The specification does not say anything about the loads on the journal bearings (that is, perpendicular to the cone axis) as one of the forces to be equalized. The journals carry a substantial proportion of the WOB, as a quick look at Figure 2 makes clear. To this extent, equalisation of WOB per cone will tend to make the journal loadings more equal.

(c) The words 'axial force acting on each cutting structure per revolution of the drill bit' may be thought to suggest a different axis but the phrase 'force per revolution' read literally is more or less meaningless because the force will not increase with the number of revolutions. If one remembers that the force on individual teeth will vary greatly as they enter, interact with, and leave the uncut formation on the hole bottom as the cone rotates, it seems sensible to suppose that what the claim is probably looking at is the average axial force over a rotation of the bit, i.e. over somewhat more than one rotation of a cone.

(d) Feature (c) of the claim seems to me to throw no light on the question which axis is being talked about. To equalise forces acting along the axis of the cones makes sense, since it will tend to equalise wear on the cone thrust bearings. It is also one of the forces expressly referred to in paragraph [0042] and [0043]. To equalise WOB per cone also makes sense. Feature (c) is accordingly indifferent as to the nature of the axial force under discussion, and the same goes for (d) and (e).

(e) Claim 6 does provide some oblique support for the construction for which Halliburton contend. It calls for a bit in which in use 'the axial force on each of said cutting structure[s] is between [31%] and [35%] of the total of the axial force on the bit…'. It is only possible to construe claim 6 so as to be consistent with the meaning of claim 3 for which Smith contends if the word 'force' relates to the magnitudes of the axial components of the forces on the cones, ignoring their direction, since they are more or less at right angles to the bit axis. There is every reason to make the cone-axis components of the cone forces equal in magnitude (this is what equation (5) describes) because that will ensure that the forces acting perpendicularly to the bit axis sum approximately to zero. Nobody suggested a plausible reason for relating them to WOB at all. This claim plainly relates to the bit-axis component of the force on each cone.

77. I have no doubt that the draftsman is here guilty of avoidable obscurity and ambiguity, and I think an unfair burden is placed on the reader. But I have concluded that the construction for which Halliburton contend is the right one. I reach this conclusion with some diffidence, since the contrary considerations are strong ones.

Construction: repeat…until

78. This point arises principally as a problem with infringement of claim 3. The claim (and I do not understand there to be any dispute about this) calls for a repetition of the calculation of the axial force on each cone and the adjustment of 'at least one geometric parameter of the design of each [cone]' until substantially the same axial force will act on each cutting structure when the bit is drilling into simulated rock. Indeed, the case was opened on the basis that the inventive concept of this patent lies in the appreciation that the axial forces on each cone should be balanced, and that this should be done by calculating the forces on each tooth and thus on each cone, and adjusting the design and recalculating those forces until balance is achieved. In other words, the criterion according to which the designer must finally decide whether the adjustment was appropriate or inappropriate is whether it leads towards or away from equality of per-cone axial forces.
79. However, I consider that this is far from abundantly clear, either from the words of the claim, or from paragraph [0052] or from Figure 6, the flow chart. The claim does not expressly suggest that the adjustment of the geometric parameter need be in dependence upon the comparison of step (c): all it says is that adjustment must take place and the process is iterated. If, therefore, a designer does not satisfy himself that his cycle of simulations is complete by reference to per-cone axial force, but adjusts his geometric parameter by reference to other criteria, albeit that the result of the application of those criteria may well be that per-cone axial force is equalised, at least to the limits of claim 6, does he infringe claim 3? To take an example, suppose it were affirmatively demonstrated that the designer did not look at the relevant output of the software, but by selecting according to other criteria nonetheless arrived at a bit which the software considered to be force balanced. I think that in such a case there is no infringement of the method claim.
80. More importantly, however, it seems to me that where the criteria include axial force balance and the result of juggling the various design variables with an eye on force balance results in a force balanced bit there is infringement, even if force balance is not the sole or overriding criterion.

Construction: the product claims

81. Claims 6 and 7 are as follows;

'6. A roller cone drill bit comprising:

- three arms;

- one rotatable cutting structure mounted on each one of said arms; and

- a plurality of teeth on each of said cutting structures;

wherein the number and locations of said teeth are not identical between ones of said rotatable cutting structures;

characterised in that the axial force on each of said cutting structure is between thirty-one percent and thirty-five percent of the total of the axial force on the bit when the drill bit is drilling into a formation.

7. A roller cone drill bit comprising:

- three arms;

- one rotatable cutting structure mounted on each one of said arms; and

- a plurality of teeth on each of said cutting structures, wherein the number and locations of said teeth are not identical between ones of said rotatable cutting structures;

characterised in that the volume of formation drilled by each of said cutting structures is between thirty-one percent and thirty-five percent of the total volume drilled by the drill bit when the drill bit is drilling into a formation.'

82. The issue on construction. The first issue is the meaning of the phrase 'when the bit is drilling into a formation'. There is a secondary issue, important for infringment, as to the precision of the numerical limits.
83. The skilled man knows after reading the specification that a given bit may be balanced in one formation but not in another. The words in question can describe a bit (balanced in such-and-such a formation with such-and-such a WOB at such-and-such RPM) but what if the designer did not have those conditions in mind when the bit was designed?
84. It seems to me that the skilled man knows that there is no way of actually measuring the load on a cone in use. This means that to place Smith's interpretation on claims 6 and 7 is likely to result in a finding of insufficiency, unless it can be said that the specification provides a description of such a measurement. Smith submit that it does so: run the bit design (however made) through the simulation program disclosed, and determine whether that program says that the bit is force balanced or not.
85. Halliburton do not accept any of this. They contend that the claim, purposively construed, is to a bit 'designed so as to be balanced in the design formation and parameters'. They say the claim is a claim to a bit however designed provided that it was designed to be balanced. The difficulty with this construction is that it makes the claim a 'product by process' claim but, as written, there is plainly no reference to the process in the claim. Moreover, where does this leave the bit which was primarily designed with an eye to other parameters, such as rate of penetration, but comes out balanced?
86. In my judgment, the skilled reader will not construe the product claims so as to imply a method of design of the bit. I think that the claim is accordingly vulnerable on two grounds: for anticipation, because it is not limited by reference to the method by which the bit it covers was designed; and for insufficiency, because the claim covers balanced bits arrived at by methods of which the patent is completely silent.
87. I have already expressed the view that read in the light of the specification as a whole these words as they appear in the method claims obviously relate to the conditions of a simulation. There is no way of measuring the force on each cone, or the material removed by each cone, several thousand feet down in rock. The product claim is however a claim to an object (a drill bit) which is not expressly required to be manufactured using a simulation technique. The phrase cannot be viewed as introducing a product by process feature, and Halliburton's contention to this effect seems to me to require a wholesale re-writing of the claims going beyond anything which might be thought to be legitimate under the guise of construction. So I conclude that in the product claims these words relate to real rock. In the end it probably does not particularly matter, because a simulation provides evidence, which may be the only evidence, of what the performance of the bit is in real rock. But all the evidence must be considered, and if the simulation is inconsistent with other evidence, then it may appear too inaccurate to rely upon.
88. The second question raises a very difficult problem. All drill bits are designed and manufactured using CAD/CAM techniques. The CAD files for the bit are processed and input into the simulation, which announces that the per-cone axial load is within the numerical limits specified. But it has to be accepted that different simulations may in principle achieve different results. It was strongly argued by Halliburton that the task of the patent was only to disclose enough information to enable a simulation to be constructed, not the last word in simulations nor even a particularly accurate one. To take an important example, it was not necessary to adjust the bit/cone speed ratio at all. So a given bit, simulated in a defined formation, might or might not appear balanced according to the criteria of the claim depending upon the details of the simulation.
89. I can see no reason not to give the claim a wide meaning in this respect. It must be the case that the designer of a simulation is not merely pursuing a simulation that works, but one that objectively produces at least as good a result as the prior art did with its dull bit analysis. After all, the designer of a simulation that actually produces a worse product than the prior art will have failed commercially. It follows that bit designers will be aiming for results that are better than those that dull bit analysis provides and thus that the adoption of criteria such as 'the axial force on each cone is between 31% and 35% of WOB' will have an objective meaning to those designers. Their simulation is bound to be an approximation but until two practically useful simulations can be shown to produce meaningfully different results on these criteria the problem is more apparent than real.
90. In this respect, and perhaps in this respect alone, Smith were not assisted by the fact that Halliburton do not appear on the evidence to have implemented the invention of the Force Balancing patent. No evidence of fact was led by the patentees, and no other evidence given, suggesting that Halliburton had a method of simulating drill bits that fell within the claims, or, indeed, owed anything to the teaching of the patents. Halliburton could not simulate a Smith design, and so the possibility of different answers on claims 6 and 7 remained, as I have indicated, theoretical.
91. For the same reason, I see no reason to construe 31% and 35% as meaning anything other than the specified number to two significant figures, so including 30.5% to
92. 4%, or 30.50% to 35.49%, or 30.500% to 35.499%.^[6] These are implied statements about the precision of the measurement, no more. They are not statements about its accuracy.
93. Finally, I must mention the question of infringement in cases in which although the software indicates that force balance satisfying claim 6 has been achieved, the designer has not used the method of claim 3, having ignored the force balance in making his design choice. If the claim were to cover such a case, it seems to me that it would be too wide and in consequence the specification would be insufficient in the way described in detail by Lord Hoffman in Biogen v Medeva [1997] RPC 1. This would be an example of the case of a claim which covered embodiments which owed nothing to what was taught by the patent in suit. This is nonetheless a difficult question, and since I am satisfied that the claim is invalid for insufficiency on what Neuberger J called the 'classical' basis in Kirin Amgen v TKT, I do not propose to say more than to observe that this particular difficulty of interpretation is a clear pointer to invalidity on the Biogen basis as well.

Infringement of the Force Balancing patent—general

94. If I am wrong on the meaning of 'axial' in the claim, there is no infringement, either of claim 3 or claim 6. Smith do not design or manufacture bits within the jurisdiction, so infringement of claim 3 is alleged by virtue of subsection 60(1)(c) of the Patents Act 1977. The invention is a process, and so the product sold in the United Kingdom must be obtained directly by means of the claimed process. 'Obtained directly' has been considered in two cases cited to me, particularly Pioneer Electronics Capital Inc v Warner Music Manufacturing Europe GmbH [1997] RPC 757, and a decision 'Halbleiter-bauelemente' in the Landgericht Dusseldorf 6 May 1997. The Court of Appeal have held that 'obtained directly' means 'without intermediary' or immediately. This seems to exclude the possibility of further processing: but the Halbleiterbauelemente case suggests that further use or processing may take place provided that its effect is not to obscure the qualities of the product directly obtained.
95. The result of the performance of the claimed method is, if I am right on the question of construction, a CAD file containing a design of bit balanced under design conditions. The CAD file is input to a numerically controlled milling machine to produce (separately) the cones, either milled in one piece with the teeth or with recesses to receive the inserts, which are themselves milled to the design recorded in the CAD file. The cones are then assembled with the associated bearings, seals and other ironmongery into a bit body. Is the result 'directly obtained' by means of the process?
96. Smith's approach to this question is understandably to point to the design as the endpoint of the claimed process, and to decompose the subsequent manufacturing process into as many steps as reasonably possible. Whatever is using the CAD files resulting from a session with the simulation software is not obtained directly by use of the process but (I paraphrase) by employing the design in further manufacture. They identify the following steps as producing 'an independent article which is not the thing that came out of the claimed process'—

1. Incorporation of the cutting structure CAD file into a larger overall CAD file including bearings and legs;

2. Production of engineering specifications, bills of materials, manufacturing drawings, tooling lists, CNC programs;

3. Manufacture of the legs, a complex process in itself;

4. Manufacture of cones with milled teeth including the steps of forging, rough boring, external machining, shot-blasting, case-hardening, grinding and turning— the complexity of milling a cone with integral teeth can be seen immediately from the figure on for example page 10 of Halliburton's inspection report, which is a Pro/E display showing what the result should look like;

5. For cones with machined inserts, the like complexity, with the addition of drilling the holes and pressing them in;

6. Finally, cleaning, greasing and assembly of the legs, followed by insertion of ball bearings and the plugging of the hole, and welding together of the legs.

97. I do not think that it is sensible to view manufacture and design as in some way resulting in separate products. Design is no doubt interesting in the abstract, but when it is used it cannot be divorced from the article made to it. The Registered Designs Act 1949 and its predecessors encouraged lawyers to consider a design as something complete in itself and distinct from any article, but from the point of view of a bit designer the design exists only as a depiction of a bit that is to be made and used. There is no doubt that the criterion with which the claimed method is concerned depend upon the bit shape as a whole (I shall discuss this further when I consider insufficiency) and it follows, it seems to me, that there is no intermediate between this method and the resulting bit, which is as much the direct product of the design process as it is the product of the manufacturing process of which the design is part.
98. I should add that the EPO's great reluctance to grant 'product by process' claims on the unchallengeably logical basis that novelty cannot be conferred on an old article by making it according to a new process encourages me to give section 60(1)(c) an interpretation that goes as far as a product by process claim might go, but no further. To the extent that these claims do relate to a mere method of designing divorced from manufacture, they are too wide for reasons I discuss below, but the cure is in my view straightforward.

The IDEAS software in use

99. There is a detailed description of the allegedly infringing software in the Product and Process Description (PPD) produced by Smith. Halliburton conducted an inspection of the software in operation, and this resulted in an inspection report. These are both substantial documents, and it would be pointless to précis them here. Although Halliburton say that the inspection made much clear that had been obscure in the product description, the deficiencies were not brought home. Dr Huang, who designed the software on the basis of Dr Ma's work, deposed to the accuracy of the PPD and was not challenged. I shall return to Dr Huang's evidence below. On top of Dr Huang's unchallenged evidence, Mr Portwood, Smith's senior bit designer until 1999 and Project Manager thereafter, gave evidence that the PPD accurately recorded the way in which Smith's bit designers used the software available to them. Smith design and manufacture their drill bits as follows.
100. The design of a bit is divided into three phases, referred to as the Baseline phase, the IDEAS Software phase and the Designer Input phase.
101. The Baseline phase starts when the designer of the bit receives a document called a Product Development Plan (PDP) which contains a field engineer's statement of requirements for the bit. It includes particulars of the rock for which the bit is intended (the target formation), the intended WOB, the rotational speed range in RPM, the depth at which the bit is to be used and a statement of the objectives to be achieved by the bit in terms of rate of penetration (ROP)—a key parameter—and durability in terms of footage.
102. On the basis of the PDP a nearest existing bit is selected (it may be identified in the PDP) and the CAD file for that bit obtained. A file called the 'insert/rock' file is also obtained.
103. The insert/rock file contains data specifying how the chosen insert interacts with the specified formation. As I have explained above, inserts come in shapes lying between two basic shapes, chisel and rounded top, and it is necessary to know how the specified type of insert interacts with the formation for which it is intended. The data is obtained by studying the behaviour of the insert as it is pressed into a sample of the specified formation and as it is scraped through the sample formation, all at a confining pressure appropriate to the depth at which the drill will be drilling. If there is brittle fracture, a further study of the resulting craters and their size is performed. For a given PDP an appropriate insert/rock file may already be available, or it may have to be generated.
104. The second phase of the drill bit design is the IDEAS software phase. The purpose of the IDEAS software is to simulate the action of a specified bit in a specified formation. The inputs to the software fall into three classes: (a) geometric, describing the bit and its inserts; (b) the insert/rock file; (c) the specified drilling conditions (WOB and RPM) and (d) the simulation conditions.
105. Initially, the geometric data is generated from the CAD file for the baseline bit. The insert/rock file is described above. The drilling conditions are derived from the PDP. The principal simulation condition is the angle through which the drill is turned between each step of the simulation and the number of such steps. Finally, an estimate of the cone to bit speed ratio is provided.
106. It will be recalled from the discussion of the patent above that the cone to bit speed ratio is not a straightforward quantity to calculate, because of the complexity of the interactions of the inserts with the formation and the offset of the cones, which produces a scraping movement. Paragraph 21 of the PPD describes in detail the manner in which the cone to bit speed ratio is recalculated in each step of the simulation.
107. The algorithms used to compute the forces acting on the individual teeth through each step are not described anywhere in the evidence (I believe that Professor Newland is unaware of them) but it is clear that they are complex.
108. The Designer Input phase of the process involves the use by the designer of the very extensive data that is output by the simulation to change the design of the bit. The designer's contribution is described in part C of the PPD (paragraphs 54 ff). There may be many iterations with intervening design changes. The IDEAS software permits certain changes to the design of the bit to be made without recourse to the CAD software^[7], but of course those changes will have to be transferred to the CAD software before the CAD files are used to manufacture the inserts, cones and bit.
109. So far as the Force Balancing patent is concerned, the relevant part of the PPD is ultimately Annexes 1 and 2, which contain a print out of from the IDEAS program which summarises the calculations carried out in a simulation. There is one parameter, called Fz_aver, for each cone (see the top of page 52 for the commented version). Fz_aver is a calculated quantify that represents the average force on a cone over the simulation (30 rotations). Similar information is conveyed by Figures 28, 29 and 30, which show displays produced by IDEAS. In Figures 28 and 29 the vertical axis denotes the percentage of time each cone was subjected to the force specified along the horizontal axis of the plot. The 'box-and-whisker' plot of Figure 30 shows the median (not mean) value of the force, together with an indication of the spread of the forces through each step of the simulation.
110. Necessarily, if at any point in time there is no force acting on a cone, that fact will not figure in the computations of Fz_aver, which is derived only from data obtained when there was such a force. Obviously, however, Fz_aver is of sufficient importance that it is reported on the calculation summary sheet. Smith decline to rely upon the fact that it may not be a true average, in the sense that there may be moments when there is no force acting on a cone and those moments do not go towards computing Fz_aver. That there may be such moments appears from the box & whisker plot at Figure 32.
111. As will be apparent, the data provided to the designer by IDEAS goes far beyond Fz_aver, and extends (for example) to instantaneous components of forces acting on the individual teeth, the rows and the cones in the radial direction (along an axis in the plane of the hole bottom), the axial direction (in the sense of hole axis) and tangential direction (in the sense of normal to the radial direction), the time averages and the histories of those forces. The PPD indicates that there are ten types of data output which the designer may choose to view (see paragraph 32 and the ensuing explanation of each of the ten types of data).
112. The choices made by the designers may therefore be driven not exclusively, or even principally, by a desire merely to achieve equality in the axial forces acting on the cones. The principal desire is to produce a bit having the desired ROP under the conditions specified to the designer in the PDP. A good description was given by Amardeep Singh, who has considerable experience in designing bits using IDEAS. He gave the following unchallenged evidence in respect of a bit referred to as the 'Singh/11' bit, which was promoted and sold as force-balanced.

'14. As 1 have explained, my objective in producing this design was to create a bit that could compete effectively with an existing Hughes product. I identified that the Hughes product had a weakness in the gage row [the outermost row on each cone]. In order to design around this weakness I identified the following (in decreasing order of importance) as optimization criteria for my design:

• Gage Forces;

• Gage Scraping Distance;

• ROP; • Fz Inserts; and

• Cone Balance.

15. I set out my optimization criteria in a Power Point presentation which I gave at the design review meeting which the design team normally holds to discuss new designs. A copy of that Power Point presentation is attached marked Exhibit "AS-6". The first of my criteria was to optimize the forces acting on the gage row of each of the cones of the bit. It can be seen from the charts on page 13 of the Power Point presentation that compared to the 15 MFD and the GFi18 bits, the forces acting on the gage rows on my new design were much lower. The second criterion was to optimize the scraping distance that was covered by each of the gage rows on my design. Page 14 of the Power Point presentation demonstrates that I was able to even up the distance (and therefore the amount of work) that each of the 3 gage rows covered in my new design. My third criterion was ROP. As page 15 of the Power Point Presentation clearly shows, my new design had a much faster ROP in the Leuders Limestone than the comparator bit. It also performed marginally faster in the Carthage Marble than either the 15MFD or the GFi18. My fourth criterion was to optimize the Fz force on each of the inserts of my bit. I was attempting to create a design where the highest force acting on any one tooth at any one time was lower than any of the baseline or comparator bits that I had investigated, in order to avoid insert breakage, particularly on the drive rows of the bit. The drive rows are essentially the 'middle' rows on the cone in between, but not including, the gage row and the nose row. Finally, my fifth optimization criterion was to balance the cones on the bit that I designed. By this I mean that, to the extent possible without detracting from what I had achieved for the other more important criteria, I was attempting to balance the Fz forces acting on the cones of this bit. However, this was only one of my optimization criteria. In fact it was the least important of the five criteria that I identified and, as with all the design work on bits, the final design was a compromise, trying so far as possible to achieve my various goals. As a result it is difficult to quantify how well I achieved my goals and, in particular, this last one.

16. Unfortunately I cannot remember which cutting structure I used as my starting model in Pro/E when I created this design. However, I think that I probably used the cutting structure design for the GFi18 as my start point, and then made alterations to that in order to create my new design. As far as I recall, the changes that I made to my starting design were made in Pro/E. I do not remember whether I used 1ayout.tk at all.'

113. He explained this further in cross-examination (Transcript 1277-8):

3 Q. We have seen that one of your optimization criteria was to

4 balance the Fz forces as indicated in the product and process

5 description. When you were designing the 174GXI, that was one

6 of your criterion.

7 A. Yes. Obviously, as everyone understands by now, balancing the

8 forces on the cones is not going to hurt anything. To an

9 extent, yes, that has been one of my criterias when

10 I designed. It is not always the most important criteria. On

11 a mill tooth bit, my Lord, typically you are drilling a soft

12 formation; so the key there is how fast you can drill. They

13 do not drill for too long, there is not too much wear on the

14 bit, so all the other factors that you are looking at cannot

15 sacrifice the ROP. You are trying to compromise between ROP,

16 the forces on the cones, forces on the teeth, and so on, but

17 the predominant factor on a mill tooth bit is ROP because you

18 want to drill fast.

19 In the end, you have to land up feeling happy about

20 a compromise that you made, that, OK, the forces on my cones

21 are 38%, 29%, close enough, but my ROP is 20 % faster. Now

22 I would not drop my ROP or sacrifice it to be 15% faster in

23 order to get my forces to be 33, 33, 33. That would not make

24 any sense for that specific bit. Yes, I would look at the

25 forces on the cones, but that would not - not at the expense 2 of ROP, or some of the other factors that I was looking at.

114. Mr Portwood gave rather similar evidence (transcript 1210):

8 Q. There are a number of internal Smith documents stressing that

9 force balancing, that is the Fz force one was talking about,

10 has an optimization criteria. Would you agree that it was

11 known amongst the Smith designers that when designing

12 a criteria, an important criteria was to attempt to force

13 balance the Fzs?

14 A. Again, I guess you have to go back to the deposition. It

15 depends on the application of the rock that you are drilling.

16 Also you are talking about a prior art pre-IDEAS design or

17 IDEAS design?

18 Q. I am talking about IDEAS designs.

19 A. Yes, it just depends. For softer rock, maybe it is not a good

20 idea.

115. This evidence, taken with the fact that in some cases a designer will simulate a bit under more than one set of conditions of WOB, RPM and formation, gives rise to a real problem in relating the words of the claim to the real world. While I have attempted to interpret those words in their context in the specification, their application to a real-world bit design provokes a number of questions. Most important is the significance of the iteration of the design adjustment and simulation cycle 'until substantially the same axial force will act on each cutting structure when the bit is drilling into a formation'. On the footing that the words 'substantially the same' must be construed as importing the same numerical limits as are found in claims 6 and 7, is the designer to iterate until the desired condition is achieved in every set of conditions, or only in one?
116. The rival considerations are easy to summarise. In support of the contention that the bit should be balanced under all simulated sets of conditions, the specification suggests in the section entitled 'Evaluation of a Force Balanced Roller Cone Bit' (paragraphs [0042]-[0043]) that WOB, along with axial force and cone moment, is a separate optimization objective. The specification is very coy about RPM. The claim is general and therefore the bit must be balanced at least for the conditions in which it was simulated. In support of the contention that balance under one set of conditions is enough, it is said that it is immediately obvious that bits may not in fact be balanced in real formations in any event. Accordingly once the requirement of a balance is achieved in accordance with the claim under one set of conditions, it makes no sense to require balance to the same extent, which might well affect the balance already achieved, under other conditions.
117. I consider that the correct answer is probably the second, that balance under one defined set of conditions only need be demonstrated. This discussion demonstrates, if it were not already clear, that the disclosure of this patent is quite inadequate to resolve questions which obviously arise on the claims once the common general knowledge in relation to the daily use of bits is taken into account: does the bit have to be balanced in all formations for which it is sold or for which it is used or for which it is simulated, or for what? The specification provides little assistance.
118. I should add that the understanding common between the parties that the balance condition of claim 3 cannot sensibly be given a wider meaning than the numerical limits of claims 6 and 7 is correct. There is no dispute that there is no criterion available outside the specification by which to judge substantial balance, since the measurements were not available in the prior art, and the specification does not suggest an external criterion: compare Cleveland Graphite v Glacier ('thin and flexible') where the criterion was provided by the prior art.

Infringement of the Force balancing patent—the particular bits

119. There are a large number of bits (over one hundred) that Halliburton considers infringe this patent. In order to cut down the scope of the trial, I ordered each side to nominate four bits. Smith nominated two different bits made to the same design, another example of which was nominated by Halliburton, with the result that only six distinct designs need to be considered. The bits in issue were inevitably referred to by different names from time to time, and I have endeavoured to give that name. The following list contains the various bits, the numbers by which they are known to Smith, the name of the designer and any name by which the bit was referred to at trial:

(a) 122 GFi18SD: Amardeep Singh: the Singh/18 bit.

(b) 160 GXiV/160MGXi: Scott McDonough: MM8355, MM4541 and MM3439: the McDonough bit.

(c) 174 GXiV: Amardeep Singh: Singh/twist bit.

(d) 084 FGSi30ODV: Dennis Cisneros/Joshua Gatell: the Cisneros bit.

(e) 122 GFi11YV: Amardeep Singh: the Singh/11 bit.

(f) 160 MGS05V: Gary Portwood: the Portwood bit.

120. One can start with the proposition that force balancing was promoted by Smith as an advantage of their bits, both in respect of the 'Twist and Shout' range (the Singh/twist and McDonough bits) and the others. This is not to be ignored, since the fact that Smith considered that they were justified on the basis of their design process in calling attention to this feature of the bits is some indication that this aspect of the bit was among the objectives of the design process.
121. The McDonough bits. Nothing now turns on the different bits themselves, since they all have the same cutting structure (for illustrations, see section ii of the Halliburton inspection report). There were two sets of simulations, one at 20 000 lbf and one at 35 000 lbf. Fz_aver was 37.7/31.2/31.1 at 20 000 lbf and 35.46/32.7/31.8 at 35 000 lbf. The simulation was in Wellington Shale, and the bits were in fact used throughout the simulated range. His evidence was that balance was one of his criteria (Transcript 1234):

'12 Q. All right. It was just .... You were also, while using IDEAS,

13 attempting to balance the Fz force on the cones as one of the

14 criteria.

15 A. Yes.

16 Q. Your bit, as I understand it, and we have the details, you ran

17 it with different parameters, the final design, what you

18 believed to be the final design. For some parameters, it was

19 better balanced than others. Is that right?

20 A. Yes. '

122. For the reasons I have endeavoured to explain (paragraph 80 above), this is use of the infringing method. Mr McDonough did not use balance as the overriding criterion. The calculation and comparison were carried out, followed by adjustment, albeit possibly according to a different criterion, but one of the things he was trying for was force balance. I have given my reasons for preferring the view that use of the method in one set of simulated conditions is enough if it results in balance, and so these bits infringe.
123. The Singh/twist bit. This bit does not infringe. A number of WOBs and RPMs were simulated by Mr Singh, but in no case were the criteria of claim 6 met. Since force balancing was not a particularly important criterion for Mr Singh (although he accepted in cross examination it was one of them in the passage I have quoted above) this seems to me to be entirely credible, as does his rejection of the suggestion that the surviving calculation sheets did not relate to the final iteration of the design. Halliburton sought to suggest that Mr Singh's memory was faulty and that there were likely to be further calculation sheets reflecting what they call a 'balanced iteration'. I could understand this if the bit failed to meet specification for some reason, but as it is Mr Singh said that when the eight bits had been selected they were simulated in IDEAS again and the summary sheets were shown to be the same (transcript 1078 lines 12-14).
124. The Singh/18 bit. This bit is balanced according to the claim 6 criteria (30.92/34.55/34.53) and was chosen by Mr Singh for a presentation showing the improvement in force balance. This was one of the design criteria and accordingly this bit infringes.
125. The Singh/11 bit. This bit is not balanced. Again Halliburton suggest that there may have been later iterations for which the calculation summary sheets do not survive, but this cannot stand against Mr Singh's evidence that the eight selected bits were run in IDEAS and produced substantially the same summary sheets as those relied on by Smith. These bits do not infringe.
126. The Cisneros bit. This bit was iterated at least 22 times and Mr Cisneros was aiming to balance the forces on the cones, in which he was successful. This bit infringes.
127. The Portwood bit. The position on this bit is not entirely clear, but it throws light on certain aspects of the claims. Mr Portwood's evidence was that it was simulated using a rock/insert file appropriate to a chisel shaped tooth rather than the 'dogbone' shaped tooth that he had in fact decided to use. In other words, the bit as made was not simulated. This much is clear from Mr Portwood's witness statement §18 and his cross-examination on a presentation that he had prepared for the sales force (transcript 1208):

17 Q. And you are showing the sales force that as a result of using

18 IDEAS, you were able to arrive with your new (the red) bit at

19 a design which was much more closely balanced in terms of the

20 total cone Fz force.

21 A. Correct.

22 Q. Presumably if this graph was what you were showing the sales

23 force, this is data taken from the final design.

24 A. Yes. I believe this was one of the sets of data from my final

25 designs. I believe this was run at different parameters, but 1209

2 everything else remaining the same - the model and also the

3 rock file, the chisel rock file that I had used.

4 Q. And you were telling the sales force, so they could tell the

5 customer, that here you are, you had achieved the level of

6 balance we see on page 5.

7 A. Correct.

128. Mr Portwood's summary sheet that he referred to as the 'dogbone summary' shows a balance of 31.47%; 35.59% 32.93%. This is just outside the claim. The presentation, which he accepts would have come from the final design, gives a balance of 14.2, 15.3 and 15.2. Halliburton submit that this 'equates to percentage figures of 32.2%, 34% and 33.7%'. I do not think it does, quite, the figures being 31.76%, 34.23% and 34.00%, but obviously these are within the range. Assuming therefore that the run (or the calculation summary sheet) used to prepare the presentation was one of the iterations of this design that Mr Portwood carried out in arriving at the final design, which was not established, Mr Portwood's evidence establishes that an inappropriate rock/insert file was used. Halliburton suggest that this is enough for there to be infringement. This shows up an important weakness of the claim: the numbers are merely values produced by an approximate simulation. They will be affected by the approximations made (here, using a chisel rock/insert file rather than a dogbone file) and the simulation, imperfect in its own terms, shows balance. I do not consider that this can be said to have been shown to infringe.

VALIDITY—general

129. The principal objection to the validity of the Force Balancing patent is insufficiency. To summarise, Smith say that the claims are claims to obvious desiderata, that they could have been written at the priority date without invention and without reference to the remainder of the specification of the patent and that if reference is made to the specification for a disclosure that enables the skilled man to construct a computer program to assist in the iterative technique claimed, or even enables him to carry it out manually, disappointment will be the result. This observation leads naturally to the conclusion that the method claims are directed to unpatentable subject matter, and the product claims are old or obvious, a number of publications and prior uses being relied on.

Insufficiency

130. The pleaded objection is that

'Claim 1

...a) The Patent provides no or no sufficient teaching of a method of design.

(b) The Patent provides no or no sufficient disclosure of how to calculate the volume of formation cut by each tooth or by each cutting structure; what comparison is made in relation to the volumes of formation cut or how that comparison is calculated; how to utilise the results of the comparison for the purposes of the iteration referred to; or how to account for the physical aspects of drilling into a formation, in particular how to determine and apply the physical properties of the formation and/or the bit.

Claim 3

...c) The Patent provides no or no sufficient teaching of a method of design.

(d) The Patent provides no or no sufficient disclosure of how to calculate the axial force acting on each tooth and on each cutting structure; what comparison is made in relation to the axial forces or how that comparison is calculated; how to utilise the results of the comparison for the purposes of the iteration referred to; or how to account for the physical aspects of drilling into a formation, in particular how to determine and apply the physical properties of the formation and/or the bit.

Claim 6

...e) The Patent provides no or no sufficient disclosure of or how to achieve a roller cone drill bit which is characterised in that the axial force on each of said cutting structures is between thirty-one and thirty-five percent of the total of the axial force on the bit when the bit is drilling into a formation, or of the formation referred to.

Claim 7

...f) The Patent provides no or no sufficient disclosure of or how to achieve a roller cone drill bit which is characterised in that the volume of formation drilled by each of said cutting Structures is between thirty-one and thirty-five percent of the total volume drilled by the bit when the bit is drilling into a formation, or of the formation referred to.

5. If, which is denied, the Claimants' products and/or process infringe the claims of the Patent (or any of them) then the specification of the Patent does not disclose the invention claimed clearly enough and/or completely enough for it to be performed by a person skilled in the art in that the scope of protection of those claims is so wide that the claims extend beyond the patentee's contribution to the art (if any).'

131. These allegations are very broad and were not reduced in scope by any request for further information or particularisation. Within their scope a wholesale attack was mounted on the specification, principally on the basis of the evidence of Professor Newland. Before turning to the details of the objection I will briefly state my understanding of the objection.
132. It is a basic principle of patent law that the European patent application shall disclose the invention in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art (Article 83 EPC transposed into section 14 of the 1977 Act). This requirement has long been fundamental. The sufficiency of a specification is a question of fact and necessarily depends upon the nature of the invention and the attributes of the skilled person. There is no general rule, and although statements like 'you may not set a man a problem and call it a specification' or 'the skilled person must be enabled to perform the invention without prolonged research, enquiry and experiment' give a flavour of the problem they do not really help (see Mentor v Hollister [1993] RPC 7 at 10-14).
133. In the Mentor case, the Court of Appeal was attracted by the word 'routine', used by the Aldous J at first instance. This word has the advantage that it enables a comparatively straightforward test along the lines of 'does this specification require the addressee of the specification to carry out tests, or developments, that go beyond the routine?' As Lloyd LJ said in that case, a phrase like 'routine trials' introduces a positive concept, easily understood and applied. Aldous J put it like this ([1991] FSR 557 at 561):

'The subsection is concerned with the disclosure of the invention in the specification. Thus it is necessary to read the specification through the eyes of the skilled addressee to ascertain what is the invention that is disclosed. Even where patents relate to articles, the inventions disclosed in difference specifications can be different in kind. For example, the invention disclosed may relate to an article which will perform a particular function or an article which is cheaper to make that similar articles. In the latter case, it is the very essence of the invention disclosed in the specification that the article can be made more cheaply and therefore too perform the invention the person skilled in the art must be able to make the article cheaply as described in the specification. In the former case, the person skilled in the art must be able to produce the article which will perform the function, as that is the invention disclosed.

The section requires the skilled man to be able to perform the invention, but does not lay down the limits as to the time and energy that the skilled man must spend seeking to perform the invention before it is insufficient. Clearly there must be a limit. The subsection, by using the words "clearly enough and completely enough," contemplates that patent specifications need not set out every detail necessary for performance, but can leave the skilled man to use his skill to perform the invention. In so doing he must seek success. He should not be required to carry out any prolonged research, enquiry or experiment. He may need to carry out the ordinary methods of trial and error, which involve no inventive step and generally are necessary in applying the particular discovery to produce a practical result. In each case, it is a question of fact, depending on the nature of the invention, whether the steps needed to perform the invention are ordinary steps of trial and error which a skilled man would realise would be necessary and normal to produce a practical result.

The section requires the skilled man to be able to perform the invention. Such a man is the ordinary addressee of the patent. He must be assumed to be possessed of the common general knowledge in the art and the necessary skill and expertise to apply that knowledge. He is the man of average skill and intelligence, but is not expected to be able to exercise any invention. In some arts he may have a degree, in others he will be a man with practical experience only. Further, in circumstances where the art encompasses more than one technology, the notional skilled person will be possessed of those technologies which may mean that he will have the knowledge of more than one person.'

134. All the same, one must be on one's guard against formulations that gloss the statutory requirement as there is always a risk that they will end up being substituted for it. This is a particular risk where the subject of the specification is very complex and its development would anyway be expected to be accompanied by a great amount of work. What is 'prolonged' in this context? It is always necessary to keep a balance between the interests of the public and the interests of the patentee in the sense that it is necessary to guard against imposing too high a standard of disclosure merely because the subject matter is inherently complex. The general use of computers in modern technologies raises particular problems, because the writing of anything other than a trivial program requires a substantial amount of effort in writing and debugging (programming's version of trial and error), even though much programming requires no creative thought and a competent programmer will be equipped with substantial experience in his area of expertise. When such a programmer forms part of the team which is the notional addressee of a computer-based invention, it is essential to form a view of his capabilities.
135. It is largely for this reason that, as will appear, I feel uneasy about the insufficiency case based purely upon the ability of the addressee of this specification to describe the geometry of the bit and implement a kinematic model, although I accept that this work will involve a great deal of labour. Where I have no doubt the disclosure falls down is in the modelling of the interaction of the bit and the formation, and in deriving from this the forces acting on the cone. I was left with the suspicion that Professor Newland's evidence, through no fault of his own, placed the skill of the person asked to set about the geometric task somewhat too low.
136. The need to approach the specification on its own terms is particularly important here. The claim is agreed to consider a bit balanced if each cone bears between 31% and 35% of the total of the axial force on the bit when the bit is drilling into a formation. The specification must be sufficient to enable this numerical criterion to be achieved.
137. The insufficiency case as advanced has four aspects, and goes to the heart of the disclosure, since Smith say that the claims in effect require the development of a computer model to carry out the claimed method, and the amount of effort required to develop such a model is clearly undue. The four main heads, and the detailed matters on which Smith rely, are these:

(a) The skilled reader would be unable to set up the geometrical model of the bit, and in particular the transformations required for the kinematic calculations are inadequately disclosed, the volume matrix V3d0 being difficult to work out and not described;

(b) The skilled reader would be unable to calculate the forces acting on the teeth, and in particular paragraph [0040] of the specification is misleading and wrong in assuming that force and volume may be equated (equations (1) to (3)) and no method of calculating forces for the purpose of paragraph [0052] is described. The experiments, equipment and data required are not described.

(c) The skilled reader would be unable to calculate the cone-bit speed ratio, and in particular paragraph [0041](2) is obscure and may require a calculation nowhere described which is both complex and difficult; and

(d) The section of the specification entitled 'Design of a Force Balanced Roller Cone Bit' contains such inaccuracies and omissions as would prevent the skilled reader from designing a bit by following the instructions provided.

138. These allegations are not independent of each other. I shall attempt to explain the problem in my own words. Paragraph [0041] of the specification describes the model. The bit rotates at the bottom of the hole. The weight on the bit is carried by the toothed cones that are driven to rotate by the rotation of the bit and the interaction of the teeth with the rock. As the cones rotate, the teeth enter and leave the rock that is being drilled. The forces on the teeth determine the forces on the cones. When the rotation of the bit is simulated, it is initially taken to rotate at a given speed. The forces that would act on each cone under these conditions have to be calculated, using a model of the interaction with the rock of the individual teeth carried by the cone (paragraph [0040] is said to describe a particular, non-essential, way of modelling the interaction of tooth and rock). As the cone rotates, the model is supposed to analyse the penetration of each tooth into the rock at predetermined intervals, and to compute the forces acting on each tooth, the forces acting on each cone, the forces acting on each bearing supporting the cone and hence the forces acting on the bit. It also should compute a rate of penetration.
139. The patent is directed towards a computer-based invention and depends upon a mathematical analysis of the system I have attempted to describe. It is a striking fact that there is no description in clear terms of any technique which assists in the construction of the model. If the patent is to escape a finding of insufficiency, much must therefore be available as part of the common general knowledge of the collective membership of the team. I have already indicated that I do not consider that it is legitimate to consult the papers referred to in paragraphs [0020] and [0022] of the specification, but in case I am wrong on this I will indicate my conclusions on the alleged insufficiencies on both bases.
140. Halliburton seek also to supplement the disclosure of this specification by reference to the Orientation patent. I have explained above why this is not legitimate, and such are the problems with the Orientation patent that there is no point in discussing the objections to this patent on the basis that the Orientation patent is incorporated by reference.
141. The geometrical model and transformation matrices. The addressee must construct a suitable geometrical model of the bit. This is essentially an algebraic problem. Halliburton emphasised, correctly, that there is a vast amount of common general knowledge in the manipulation of digital images to give a three-dimensional appearance and so on. Any sophisticated CAD system can rotate the images it displays and many such CAD systems were available at the priority date. In these systems rotations are (or may be) described by matrices, and so the construction of a model is not beyond the skills of an ordinary computer modeller. However, the model is intended to simulate the rotation of a bit and its component cones and teeth under the constraints I have tried to describe above. The crucial problem is thus both the kinematics of the bit and its components (i.e. how they move relative to each other) and their dynamics (the forces acting on them).
142. Professor Newland gave this answer in respect of bit kinematics (transcript 844ff):

15 MR. BURKILL: I was going to since that one was just a for

16 instance. Let us move on to drill bits specifically. Leaving

17 aside your rate of penetration concern, which we will

18 obviously come to, the computer modeller would be able to

19 model a roller cone drill bit if provided sufficient geometry

20 to show the position of teeth, cones and bit relative to each

21 other and those could be combined into an assembly and

22 displayed on a computer screen, could they not?

23 A. I do not agree that it is an easy problem. If I explain how

24 I see it, perhaps that will help. The problem is one of

25 3-dimensional geometry as far as I think your question is. As

2 a concept, it is clear what is happening. One can easily

3 visualize this thing descending and the cones rotating and the

4 teeth moving and saying that I could put a spot of white paint

5 on one tooth in one position, then as the thing moves I could

6 take, for example, photographically a series of pictures and

7 I would be able to see where that point had moved in the

8 operation of the drill bit. But it has to be said that the

9 geometry is complicated. Whether you use matrix methods or

10 whether you use Euler angles -- in another reference you show

11 me Euler angles, or Bryant angles or Euler parameters, or the

12 3-dimensional trigonometry that Ma use^[8], whatever you use, the

13 result must be the same because that point has one and only

14 one trajectory, given the starting parameters. So whether

15 this calculation is done by matrices and transforms or whether

16 it is done by 3D geometry in the way that Ma did it, the

17 upshot must be the same. Otherwise either Ma is wrong or

18 whoever has done it is wrong. There is not any doubt about

19 it. It is 3D geometry. It has an answer right or wrong . If

20 the correct answer is arrived at, my position is just this,

21 that it does not make it any easier to do it by matrix

22 transforms than to do it by the method that Professor Ma

23 adopted. In the end you have to come to the equations that

24 are in Ma's book which tell you where that little spot of

25 white paint is at every instant of time. Although we can

2 discuss matrix transformations, and of course they are in the

3 engineering undergraduate curriculum, that is completely

4 different from saying here is a complicated 3-dimensional

5 geometrical problem, what is it solution?

143. Professor Newland was the only one of the witnesses with a hands-on knowledge of computer modelling. It is a difficult problem. It can be solved with known techniques. Professor Cooper considered it to be a matter of development, rather than a research problem. But it is obviously a problem. There is no discussion in the patent as to the correct techniques. It should be noted that we are not concerned with a problem where Professor Newland's lack of familiarity with drilling is a handicap: this problem relates only to the geometry of the system.
144. The irrelevance of the existence of CAD programs was emphasised more than once by Professor Newland (transcript 848):

8 A. My position is that CAD was commonplace in the industry. It

9 could model the shape of very complex mechanical engineering

10 components like a roller drill bit, so that it would produce

11 effectively a photograph of the device in three dimensions and

12 could you look at it from above, from below, the side and at

13 an angle. All that could certainly be done, but what it could

14 not do is model either the kinematics or the dynamics of how

15 the drill bit works.

16 Q. In the ground. Works in the ground is ----

17 A. The kinematics is not in the ground. The kinematics is

18 a theoretical exercise with the drill bit, if you like, in

19 suspended animation -- not cutting. That is what Ma deals

20 with in his chapter 2 and reaches the equations in chapter 2

21 that I am talking about - his kinematic equations. Then

22 another issue is the whole one of tooth to formation

23 interaction.

145. On the basis of a Smith patent that refers to Ma's publications for the kinematics, the following exchange occurred. Professor Newland had expressed the view that working the kinematics out was a suitable project for a master's degree:

13 Q. But, on the other hand, you might reward him for using

14 a little initiative in appreciating that these things are all

15 out there already, would you not?

16 A. Well, in describing the project as I have, I would certainly

17 expect the student to study the literature and to see Ma's

18 book and the papers that led to that book and possibly the SPE

19 paper, although there are difficulties mentioning that in this

20 context, but to look at the literature. Even if I took the

21 equations straight out of Ma's book, it would still be

22 a significant project because you have got to understand all

23 the aspects of them and get the correct numbers into them and

24 model this. Following all those points on every tooth, into

25 contact with the ground and out of contact with the ground, is

2 just a huge task. I know how students get things wrong and

3 projects do not work out, even though they may seem to be

4 conceptually very simple. The devil is in the detail of this

5 project, in my opinion.

6 Q. But all this could be done with techniques known in the art

7 well before 1998.

8 A. They would be using conventional techniques for 3-dimensional

9 computer modelling.

10 Q. So you would not disagree when Smith, in their own patent, say

11 that this is something that could be done using techniques

12 known in the art?

13 A. I would not disagree that it uses techniques known in the art.

14 It is just that they are complex and getting it right is

15 a difficult thing to achieve.

146. Mr Hall accepted that this was 'a lot of work'. Even if it were legitimate to look at the Ma book, which is not shown to be common general knowledge, this evidence would support a suggestion of insufficiency. Without the Ma book not enough is disclosed, and it was not suggested that the Ma paper helped in this respect. As I have indicated, I feel uneasy with the allegation of insufficiency based on geometric and kinematic considerations alone, but in the end I think that the balance of the evidence tips in favour of a conclusion of insufficiency.
147. The kinematics of the bit require a knowledge of the rotational speed of the cone. The correctness of the speed of rotation adopted for the cone is checked by considering the torques acting on the cone (paragraph [0041](2)). Professor Newland thought that this paragraph was unclear, but considered that it probably indicated that the suggested step involved calculation of all the forces acting on the cone. If the model suggests that the forces acting on the teeth combine to produce a torque which is out of balance when averaged over (say) a rotation of the cone, the model is physically unrealistic. A cone that is supposed to be rotating at a constant average speed cannot have a net torque acting on it. This means that the cone rotational speed must be adjusted and the model re-run until the torques acting on the cones are close to zero, but, as he remarks, the patent does not indicate how close to zero. This is elsewhere referred to as calculating the cone/bit speed ratio, as opposed to choosing a value and sticking with it. There was some cross-examination of Mr Hall directed to showing that a small percentage error in the cone/bit speed ratio would result in a substantial cumulative error over (say) a ten-second simulated rotation of the bit (transcript 516):

10 Q. To get a sufficiently accurate determination of the cone to

11 bit speed ratio, to make one's model worthwhile, one would

12 need to consider the forces acting on the teeth.

13 A. I feel that that would be desirable, yes. It is not

14 essential, but it is desirable to get accurate results, yes.

15 Q. If we consider together a cone to bit speed ratio, it may be

16 anything between 1 and 1.5, may it not?

17 A. Typically they would be included in that range. 1 would be an

18 abnormal one, but 1.2-1.5 I would feel to be a more reasonable

19 potential range.

20 Q. 1.2-1.5. If, for example, one has an error of, say, 1% to the

21 cone to bit speed ratio, that translates into 3.6 degrees

22 every rotation of the bit, does it not?

23 A. It would.

24 Q. And over 10 seconds, a period of simulation considered by this

25 patent, there may be 40 revolutions of the bit, may there not? 517

2 A. There may be.

3 Q. So even with a 1% error, the estimate of cone position may

4 bear no relationship to reality. Is that fair?

5 A. That is the potential problem that exists with any simulation.

6 There is the error that can result. I will accept your

7 numbers. Yes, I would agree.

8 Q. Accordingly, to determine the forces acting on the cone with

9 any reasonable degree of accuracy, may I suggest to you that

10 it is therefore necessary to actually calculate the cone to

11 bit speed ratio by taking into account the forces acting on

12 the teeth as they interact with the formation?

13 A. I would agree that that should give you the most accurate

14 results. In fact, a varying cone to bit speed ratio would

15 enhance the accuracy of the results.

16 Q. And, indeed, that is what you need to get a worthwhile model.

17 A. The term "worthwhile" would be a controversial term. You can

18 get a simulation without total accuracy. The better the

19 accuracy, the more reasonable the simulation. Professor Ma

20 thought that he was doing meaningful stuff, and I do not

21 believe that he had an accurate determination. My point is

22 that the more accurate the result, the input, the more

23 accurate the output. That is true of any simulation.

148. If Mr Hall's evidence is accepted at face value, this is a problem that will confront any person designing a simulation of this type. You cannot get the kinematics right without an accurate cone/bit speed ratio. It seems to me that the disclosure should be sufficient to enable the skilled reader to achieve balance in the specification's own terms, which necessarily involves balance within 31% and 35% of the total axial force on the bit. No other criterion is supplied by the specification. If such accuracy can be achieved without adjusting the cone rotational speed in accordance with paragraph [0042](2), it is plainly the duty of the patentee to say so, and to indicate how the required accuracy can be achieved. The reader must be told what is important and what is just refinement, particularly where the refinement introduces computational difficulties of the kind described by Professor Newland. This is an insufficiency, without considering the question whether it is possible to calculate the cone/bit speed ratio.
149. The question of the volume matrix V3d0 is straightforward. It cannot be calculated without a working simulation, as Mr Hall accepted and as the specification makes clear in paragraph [0047] itself. On the other hand, a working simulation cannot be constructed without it. If, therefore, the specification teaches using the volume matrix for any relevant purpose, it is insufficient. Since it says (paragraph [0046]) that the force acting on an element (as described in paragraph [0040]) is proportional to the volume removed by that element, and the principle applies to any tooth, and that this is the second stage in the optimization procedure, it seems to me to be important to the disclosure. I find that insufficiency is established in this respect.
150. Calculation of the forces acting on a tooth. The specification seems to describe two methods of achieving force balancing (see paragraph 57(d) above). The first is to achieve volume balance. This takes up the whole of the description of the preferred embodiment, paragraph [0052] apart. The patent does not describe direct calculation of the forces at all except in the context of the calculation of the force on a single tooth (paragraph [0040]) and paragraph [0041](4):

'The element forces are integrated into tooth forces, the tooth forces are integrated into cone forces, the cone forces are transferred into bearing forces and the bearing forces are integrated into bit forces.'

151. Professor Newland criticises the difficulties, obscurities and errors in the proposed method of calculating the forces on the teeth in paragraphs 200 ff of his report. This passage covers a number of objections. Professor Newland observed that a straight penetration was quite unrealistic: a tooth is in fact rolled into the formation at the bottom of the hole and rolled out again, and the model needs to reflect this. It was established that penetration tests in the laboratory might be used to obtain raw data about the interaction of a tooth and formation. Of course, such data is obtained for teeth, but the patent calls for the results to be translated into data for an element which may be integrated over different shapes of tooth, thus avoiding a different set of penetration tests every time a new tooth shape is used. I have absolutely no doubt that as a matter of language equations (1), (2) and (3) are disclosed as part of the structure of the force model for the tooth that will be integrated in accordance with paragraph [0041](4)^[9]: see also paragraph [0046] which relies on equation (1) as showing that the volume removed by an element is proportional to the force acting on that element, a principle that is said to apply to any tooth. But Mr Hall was pressed about their inadequacy having regard to the rolling movement of the tooth, and said this about these equations (transcript 544):

'5 A. It does not. I construe figures 1, 2 and 3 as not being your

6 modelling at all. This is the data acquisition guidance where

7 you will feed information into your model. This I do not

8 believe by any means as being the patentee's method of telling

9 you how to model. This is telling you how to determine data

10 that will be used when you do your modelling. This is just

11 describing indentation tests by which your interaction between

12 teeth and formation properties will be determined. I cannot

13 conceive of anybody believing that this would be guidance as

14 to your actual simulation. This is just guidance as to

15 determining the properties of the formation and the nature of

16 the forces that will exist when a tooth interacts with that

17 formation both in an axial and a lateral fashion.

18 Q. May I respectfully suggest that that is simply not consistent

19 with the description at paragraph 40, which is discussing the

20 use of an element force model, and it is saying that the force

21 on an element in the normal direction may be determined by the

22 application of equation 1.

23 A. I still disagree. If you will read the first sentence, "The

24 present invention uses a single element force-cutting

25 relationship in order to develop the total force-cutting

2 relationship of a cone [with the bit]". But the effort here

3 is coming up with the force-cutting relationship. It is not

4 actually performing the simulation yet. It is rather

5 determining the nature of the forces that will result from

6 either axial or lateral motion of a tooth when engaged in

7 a given formation. That is why the specific formation

8 properties are being determined here by these equations.

9 Again, my understanding is unquestionable, that it has nothing

10 to do with the simulation itself per se. It is only providing

11 me with the cutting relationship between axial and lateral

12 motions that will be ascertained during my simulation. By

13 these equations I can calculate the forces when I know what

14 the axial and lateral motions are at a given point in time of

15 analysis.

152. If Mr Hall is right in this passage, the specification does not describe the forces on the element that will be integrated over the tooth forces, and this will have to be provided by the skilled man. On the balance of the evidence, Mr Hall is probably wrong. He gave other answers that were inconsistent with what he said here, particularly at transcript 548 line 19. The passage reflects, however, a tacit acceptance that equations (1), (2) and (3) are of little use in constructing a model, a contention that was vigorously contested in the cross-examination of Professor Newland who from transcript 902 onwards was cross-examined on the basis that what Mr Hall said in the extract quoted above was wrong:

'16 Q. Yes. You break it down into vertical matchsticks. As far as

17 those concerned, if they are in contact with the rock, then

18 you use those to calculate the forces from equations 1, 2 and

19 3, do you not?

20 A. Well, as I understand what this model does, and beginning

21 initially with equation 1, it takes a matchstick of elemental

22 size Sc. It does not give any information as to what

23 that area is. It says it is a cross-section on the XY plane.

24 I understand that. It does not tell you how big it is,

25 whether large, small or infinitesimal. It does not appear to

2 come into the resulting calculation, nor does the length LE,

3 along the Z axis. This force formulation seems to say that

4 the vertical force is in proportion to the depth of

5 penetration SE to the rock parameter s, which

6 is defined as the compressive strength of the rock, and

7 a parameter ke associated with the formation

8 properties.

9 I think it must be true, must it not, that on any

10 analysis ke must depend on the area Sc and will not be

11 a property of the rock per se but the property would be

12 something to do with the size of the matchstick. At any rate,

13 the formulation says that the vertical upforce on the

14 matchstick is in proportion to its depth of penetration and

15 that you can assemble a bundle of matchsticks into a complete

16 tooth and you will then have an accurate model or

17 a satisfactory model of the upthrust on the tooth. I have not

18 seen any evidence that that is a correct realistic

19 formulation.'

153. The model is undoubtedly inconsistent. This was neatly shown by a suggestion made in the course of cross-examination to Professor Newland to the effect that the assumption that force on tooth is proportional to depth of penetration was reasonable having regard to a 1962 paper, 'The perfect-cleaning theory of rotary drilling' by Maurer. This paper suggests that depth of penetration was proportional to force for a chisel-shaped bit, that is, a tooth which, if modelled with matchsticks, would involve the penetration of additional matchsticks as the tooth entered the rock. If modelled in accordance with equation (1) of the patent, the force on a 90º chisel-shaped tooth would be proportional to the square of the penetration depth, quite different from what Maurer suggests (transcript 911-914, and X3 for the professor's sketch). In fact, everybody seems to be in broad agreement that for a tooth, force is more or less proportional to penetration, and the patent is in error in suggesting that the same relationship should hold for an element of the tooth. Equation (1) is just wrong. It was not established that the skilled man would appreciate that this error existed, let alone that it was obvious.
154. This is particularly important, given that the specification is mainly concerned with volume balancing, from which force balancing is said to follow. Equations (1), (2) and (3) are really the only direction as to how to start to approach the problem of calculating the force on the tooth. If, as Mr Hall says in the passage I have quoted above from his evidence, it is inconceivable that anybody could believe that these three equations were guidance for the simulation, the inevitable conclusion is that the specification is insufficient because it cannot be shown that the steps of [0041] can be performed from the common general knowledge at all. If, as I consider a fair reading of the specification indicates, these equations are intended to provide a guide for the construction of the model, the model is wrong and cannot give useful results.
155. I should add that if I am wrong when I say that it is not legitimate to use the Ma paper to supplement the disclosure of the patent, the force model disclosed by Ma is correct, but is a whole tooth model. To employ Ma's model, therefore, involves an abandonment of paragraphs [0040] and [0041]. Professor Newland explains why Ma's whole-tooth model is superior in a series of magisterial answers at transcript 914 to 917. None of this depends on his lack of experience of drill bits: it shows that the patent and the document said to supplement its disclosure are inconsistent in their approach to the basic problem of modelling the force on the tooth. This is not acceptable.
156. I hope I do not summarise Halliburton's approach unfairly if I say that it consisted of a contention that the skilled man would, if confronted with problems associated with the calculation of the force on a tooth described in the patent, merely abandon that analytical technique and approach the problem in another way, employing what Mr Burkill QC called an 'alternative force model'. He observed (rightly) that the single element force model is not a requirement of the claims, and the reader can use an alternative model if preferred. Mr Hall gave the following answers at 513-5:

6 A. Possibly I did not make my answer clear. I will attempt

7 again. The simulation will give me a geometric interaction of

8 teeth with formation. I can determine from that interaction

9 an axial penetration of the tooth. This equation will give me

10 the force in an axial direction that results from that.

1 I will know from my simulation the direction of motion

12 sideways of that tooth and equations 2 and 3 give me my method

13 of assigning a force value to that motion.

14 Q. I am sorry, Mr. Hall, I think I am failing to make myself

15 clear. The forces actually bearing on a tooth, as it goes

16 through the formation, may well be, and indeed are likely to

17 be, very different to the forces necessary to produce your

18 threshold mu that you have described is the practical result

19 of carrying out the tests of two and three. That must be

20 right, must it not?

21 A. I would disagree. You would recall my example of a plough and

22 the land. Once motion occurs, regardless of how far or

23 theoretically how fast you would do that, that force will

24 remain the same. Work will increase, as you go further, but

25 the force will remain the same.

2 Q. There is no explanation here as to how to take into account or

3 determine the forces acting on a tooth which is moving at an

4 angle to the surface of the formation other than axially or

5 horizontally.

6 A. It is an angle of motion not composed of axial and sideways

7 combined.

8 Q. I suggest to you, Mr. Hall, that a skilled person would

9 appreciate that the forces acting on the tooth, as it is

10 moving axially or scraping through the formation, cannot be

11 resolved by a simple application of what you have described,

12 the result of experiments 1, 2 and 3 to be.

13 A. I would submit that in my opinion, sir, it can. If I am

14 moving at an angle into formation, I am, by so doing,

15 increasing my depth of penetration and moving sideways.

16 I have equations to give me both of the forces that result

17 from those components of motion. That is what these tell me.

18 That is what they teach me.

19 Q. They only give you the threshold, do they not, as you have

20 described your mule analogy? What equation 2 on your analysis

21 gives you is the force which would be necessary to get that

22 element moving, and that is all.

23 A. That is correct, because once it begins to move, it can move

24 indefinitely at that force level.

25 Q. May I ask you a slightly different question. To determine any

2 forces, one would have to test a tooth. Is that correct?

3 A. You would have to conduct at least one test on some tooth,

4 that is correct.

5 Q. One would then have to try and work backwards and determine

6 the forces acting on each element which you have chosen to

7 use.

8 A. To utilize this preferred embodiment of breaking it into

9 elements, that would be correct. This is only a preferred

10 embodiment and, therefore, if you so chose, you could conduct

11 multiple tests on actual teeth and actual formation and just

12 use your element as one relative to that tooth; but, yes, you

13 would have to work backwards to use this preferred embodiment

14 elemental model. That is correct.

15 Q. All one can derive from that is information for an average

16 element in a tested tooth. Is that not so?

17 A. I disagree, again, an "average" element. I do not understand

18 your term there, but you would break your tooth up

19 analytically where you fix the number of elements, the

20 location of the elements, the sideways exposure of the

21 elements, and it would be up to the modeller to determine the

22 exact nature of the elemental analysis that he was performing.

157. This is a hopeless answer to the insufficiency alleged. There was no convincing demonstration of any common general knowledge in relation to modelling the force on a tooth, and, had there been, it would have had a substantial impact on the allegation that the patent was obvious. It is not up to the modeller to decide what is the exact nature of the elemental analysis he is performing. It is his job to follow the directions in the specification to construct the model, using such description as there is of the model. If no model is fully described, the specification is insufficient unless the deficiency can be made good from the common general knowledge. In this case, it was not.
158. Smith rely also upon the lack of any proper directions as to the nature of the experimental work necessary to establish a working force model. It was clearly established that there were a number of outside testing houses that would carry out penetration tests, but it was accepted by Mr Hall that special equipment would be needed to measure forces as teeth are dragged sideways through formation (this needs to be done to obtain the µ's in equations (2) and (3)) and that such equipment was only available 'in places'. Rather oddly Mr Burkill suggested to Professor Newland that the construction of such machines would be 'something of a research project' if they did not exist. Ma had found it necessary to build them at Schlumberger. On the whole, I think the patent is insufficient in this respect.
159. Calculation of the cone/bit speed ratio. The cone/bit speed ratio is of importance to the model, because the position of every tooth at every moment during the simulation is determined by it. The ratio may be different for each cone, and may be affected by any changes made to cone configuration during the iterated design process.
160. The principal disclosure is paragraph [0041](2):

'The cone kinematics is described by cone rotational speed. Each cone may have its own speed The initial value is calculated from the bit geometric parameters or just estimated from experiment. In the calculation the cone speed may be changed based on the torque acting on the cone. '

161. Two methods of producing an initial value are thus described. When the paragraphs says that the cone speed may be changed based on the torque acting on the cone, as I have indicated I understand the word 'may' to relate to the manner in which the speed is recalculated, not to the fact of the recalculation, which I find on the evidence to be essential. Mr Hall gave evidence at the trial of the parallel proceedings in the US District Court to that effect, which he confirmed before me.

'Q Could Professor Ma accurately calculate the forces on a cone per revolution of the drill bit. A No he could not.

Q Why not, sir? A He's never come up with a method of determining the true cones speed ratio to bit speed ration to be able too do that. Even though that sounds like a simple thing, it really is very important in really determining the true forces that act on a bit.

…

So the force and the penetration rate and all that sort of thing all depend on being able to accurately determine really what speed this cone is going to turn relative to the speed of the bit. And it's a very complex thing to do, because like I say, it's constantly changing. And it depends on the combination of inputs of all these teeth.

Q Now sir, is it also complicated because some of the teeth don't just actually cut through the ground, but they actually slide or skip along the ground? A. No question about it, that's correct, yes.

Q Could Professor Ma accurately calculate the cone speed too bit speed ratio? A No, he could not, and he stated that he could not on several of his publications.'

162. Mr Hall had had experience with a failed attempt to simulate a drill bit at his former employer, Hughes Christensen (formerly Hughes Tool):

'12 Q. And the patent gives you no help along that road.

13 A. It is mute along that line. I was trying, I do not know if

14 you desire it, but like I say, Hughes actually undertook to

15 attempt to develop such a program. We did work on it for

16 several years and finally abandoned it because it never

17 accurately forecast what the bit would do. That was one of

18 the reasons why we never could come up with an accurate cone

19 speed to bit speed ratio. Our indentations were not in the

20 right location, and all that sort of thing.

163. An accurate cone/bit speed ratio is essential. It is difficult to obtain. Ma does not provide an accurate cone/bit speed ratio. Nothing is provided by the patent as a method of adjusting the ratio as the simulation proceeds other than the instruction to balance the torques on the cone, but the patent does not give a proper indication of how those torques are to be calculated. The specification is insufficient in this respect. A reference to the Orientation patent does not help for the reasons I shall discuss further below. This was not part of the common general knowledge, and there can be no expectation that the skilled addressee would be able to devise the necessary calculation on the basis of the common general knowledge.
164. The adequacy of paragraphs [0042]-[0052] of the patent. The point on V3d0 aside, I do not understand that Smith find it necessary to pursue the detailed allegations set out in paragraphs 221-5 of Professor Newland's principal report, except that it is said that this section of the patent proceeds upon the assumption that a volume-balanced bit is a force-balanced bit, an assumption that in fact underpins the use of equations (1) to (3). It is false, as Mr Hall accepted. I think the proper assessment of the teaching here is that volume balancing will normally produce a force balanced bit, but that does not absolve the skilled person from comparing the forces (see Figure 6 for the design sequence) to ensure force balancing. It is not necessary to pursue this further in consequence of the adequacy of the disclosure in relation to force balancing.
165. The relevance of Smith's patents. It would not be right to leave this discussion without mentioning Smith's own US patents numbers 6,786,288 Singh ('Cutting structure for roller cone drill bits'), 6,516,293 Huang & al. ('Method for simulating drilling of roller cone bits and its application to roller cone bit design and performance'), 6,612,384 Singh & al ('Cutting structures for roller cone drill bits') and 6,619,411 Singh & al ('Design of wear compensated roller cone drill bits'). The first and last of these were not discussed with any witness^[10] and do not call for further consideration. '293, filed in March 2000, and '384 (June 2000) are relevant.
166. '293 is relied on both in respect of insufficiency and to counter any suggestion of obviousness. It is, in essence, directed towards a simulation. '384 is directed towards balancing the axial forces acting on the cones with the WOB. Two passages from '293 were put to Professor Newland. The first (col 4 lines 41-53) is merely about the design variables or parameters that will be available from a CAD system. Column 5 lines 29-65 was also put to Professor Newland, who accepted that there were no new mathematics but that the kinematic problem was a difficult one: it was in this context that he suggested sufficient for a master's degree. On the dynamics of the problem, for which the patent gives a clear direction to use the Ma paper, the position is different, because the Ma paper is expressly referred to for the method and because it is common ground that its disclosure is sufficient in this respect.

Conclusions on insufficiency

167. The last objection that Halliburton make to this formidable case on insufficiency depends upon the contrast they draw between the wide experience of Mr Hall on the one hand and Professor Newland's lack of specific experience in the industry on the other. It was submitted that Professor Newland's lack of experience deprives his evidence of much weight when it is set against that of Mr Hall. I reject this submission. I have already indicated that in a number of respects Mr Hall's evidence was not consistent. No aspect of the insufficiencies that I find established depends upon a close knowledge of the drilling industry or of the manufacture of drills. They are, on the contrary, really objections based upon the difficulty of constructing a model given the data and other information made available by the specification. The objections of insufficiency that I have set out in paragraph 136 above are all established. This patent is, indeed, grossly insufficient in relation to force balancing. So far as volume balancing is concerned, I conclude that the patent is also insufficient because at the lowest a volume balance according to paragraphs [0046]-[0048] also requires a disclosure of an adequate technique for the calculation of the cone/bit speed ratio so that the 'swept out volume' for each cone can be calculated. The patent is invalid on this ground.

PRIOR USE

168. Smith rely upon two prior manufactured bits. When the CAD files of these bits are used in an IDEAS simulation, the bits turn out to be balanced within the numerical limits of claim 6. It is accordingly contended that the claim was anticipated.
169. The difficulty is that it is not shown that immediately before the priority date it would have been possible to analyse the bits to see that they were balanced. Smith's contention is that these were enabling uses because it would have been possible to copy the bit and so make another, equally within the claim. Halliburton submit that Merrell Dow v Norton [1996] RPC 76 establishes (1) that an invention is a piece of information and (2) the use of a product makes the invention part of the state of the art only so far as that use makes available the necessary information (see [1996] RPC 86 lines 32-6). Dumb anticipations are not enough: they must speak sufficiently to tell what the invention is. But no information is conveyed by the bit: nobody knows, when they copy it, what they are copying or what distinguishes it from any other bit, although no doubt the impulse to copy may be provoked by the bit's qualities in use.
170. The contrary argument is that patents are not available for discovering a mere property of an old article. I have found Laddie J's analysis in Evans Medical Ltd's Patent [1998] RPC 517 at 573 helpful. In contrast to Merrell Dow and Evans Medical, the present case is a mechanical case in which for present purposes it must be accepted that the claim covers an infinity of different drill bits united by a single quality, balance. Nonetheless, the law has always been that clear and unmistakable directions to do or make something within the claim will, if they form part of the state of the art, anticipate the claim. It is not necessary that the prior art contain a description of something within the claim (see General Tire v Firestone [1972] RPC 457). The essential difference between the present case and Merrell Dow is that in general in a chemical case it is not possible, without analysis of the prior product, to reproduce it, and accordingly if the product is not analysable there is no relevant information. It is different when there is relevant information, even if that information does not extend to an explanation of what in fact the prior art product is. This explains Lord Hoffmann's cinchona bark example in the part of his speech in Merrell Dow concerned with anticipation by prior disclosure, which demonstrates that 'there are descriptions under which something may in a relevant sense be known without anyone being aware of its chemical composition or even that it has an identifiable molecular structure.'
171. What then if a dumb anticipation conveys sufficient information to enable it to be dumbly reproduced? The case is, it seems to me, covered by Merrell Dow the effect of which is to require a finding of anticipation. I am glad of this, because I consider that the proposition advanced by Smith, that no patent is to be granted for discovering a mere property of an old article which forms part of the state of the art in the sense that it is open to anyone to copy it, is sound in principle.
172. I have considered the right construction of the product claims above. They relate to the actual behaviour of the bit in real-life conditions, of which the simulation may be the best evidence. But evidence throwing doubt on the adequacy of the simulation must be taken into account. The evidence of Professor Cooper in respect of these two bits was that no conclusions could be drawn from the simulations because of the disparities between the historic behaviour of the bits and the simulation: it follows that prior use is not demonstrated because we do not know if they were balanced in use or not. If they had been, their sale would have been an enabling prior use, but for the foregoing reasons I reject the allegations of anticipation by prior use.

OBVIOUSNESS

173. There are five citations against this patent, and unsurprisingly Halliburton say that 'too many shots at the target make for subject-matter', for which they cite Jacob J's recollection in Honeywell v Appliance Controls (unrep 22 February 1996) of a dictum of Mr Trevor Watson QC. They overlook Jacob J's insistence in that case on taking each citation in turn for what it was worth. In the final assessment of a finely balanced argument on obviousness, it is possible that the balance will be tilted in favour of the patent if it is established that many were trying and failing: but this sort of consideration is secondary, and will draw attention away from the main question, which is what is obvious to the skilled person in the light of each cited document, taken separately and interpreted through the eyes of the skilled person. In the usual case, I think, the fact that some investigators tried and failed to solve the problem allegedly solved by the patent is irrelevant to the question with which I am confronted, unless it can be shown that those who failed were aware of the publication under consideration, and the fact of failure will therefore have the strongest effect when the common general knowledge alone is relied on, although even then it must be shown that those who tried and failed were possessed of the common general knowledge and were not the victims of idiosyncratic prejudice or ignorance.
174. I do not wish to burden this over-long judgment with a general discussion of the principles underlying the objection of obviousness. My approach will be that of the Windsurfing^[11] case. Before I start, I must construe the patent through the eyes of the skilled addressee who is equipped with the common general knowledge, and identify the inventive concept of the patent in suit. Then, in respect of each cited document, I must identify the differences between the inventive concept and the teaching of the document, and decide whether those differences amount to steps obvious to the skilled man, or whether they require invention.
175. This is a case in which the scope of the claim is important. A claim will be invalid if it covers anything that is old or obvious. The EPC expresses the test as a negative, 'An invention shall be considered as involving an inventive step if, having regard to the state of the art, it is not obvious to a person skilled in the art.'
176. The inventive concept referred to in the Windsurfing judgment is, in effect, the subject matter of the claim under consideration, shorn of immaterial verbiage. In this case, I have construed the claim to cover a process of design which involves an adjustment of the geometric parameter repeated until substantially the same axial force acts on the cone even if axial force balancing is not the final criterion: all that matters is that it is taken into account and that the resulting bit satisfies the balance criterion, even if iteration stopped when some other criterion was satisfied. If this is the right approach to the claim for infringement, so also must it be the right approach for obviousness. I will first look at claim 1 for the inventive concept. Mr Hall said it was a method of improving roller cone bit cutting structure and bits so designed by ensuring that the axial force (that is, the downforce or WOB) acting on each of the cones is substantially equal, or the volume removed by the three cones is substantially equal. This formulation does not suggest that axial force balance is the sole or final criterion, nor does it refer to the use of iterative methods, nor to the use of computer modelling, nor to any particular method of computing anything. In opening, Mr Watson QC occasionally used the word 'iterate' to refer to two aspects of the claim: (1) the computation of the force acting on the cone by starting with the tooth, and (2) the process design–simulate–alter design–simulate… until either the displaced volumes or the axial forces are the same for each cone. I will only use the word in sense (2).
177. It is to be noted also that it is suggested that certain of the prior publications are not addressed to the same 'team' as the patent, and, in particular, that it is not clear that certain of the documents are addressed to a bit designer, surely the leading member of the team, and do not suggest the use of computer modelling, or the use of an iterative technique. This point cannot be dealt with generally, and I shall consider its relevance when I consider each document.
178. Before turning to the individual citations, I wish to deal with one matter which I consider to be a matter of general engineering. This is the matter of axial force balancing. For this purpose, it is helpful to visualise a real bit. It may be as large as 15" diameter, it may be subject to a load of up to 100000 lb (45 tons) and it will be rotating at speeds between 70-240 rpm at the bottom of a hole some thousands of feet deep. It has three legs carrying cones on stub spindles, and all the load is transmitted through the bearings (journal bearings and thrust bearings) on which the cones rotate. For maximum life, it is obvious that bearing wear should be equal between the cones and the experts all agreed that one of the purposes of dull bit analysis was to even up wear between the cones. Because the cones are set at the journal angle with respect to the base of the hole, the force acting on a cone has substantial components along the cone axis and normal to it.
179. As I have indicated, Mr Hall had great experience of dull bit analysis, which is a systematic study. He accepted (transcript 379) that the bit designer would know that a major component of the load on bearings was provided by the WOB. He was not willing to accept that a designer working from a dull bit analysis would think in terms of loads, but he accepted that such a designer would understand from his ordinary knowledge that unevenness in wear was a consequence of unequal loading (transcript 382):

20 Q. And he would be aiming to ensure that the wear did not occur

21 unevenly between those bearings.

22 A. That would be one aspect that he would consider.

23 Q. And, consequently, he would be aiming, would he not, to try

24 and ensure that the loads, for example, on the thrust

25 bearings, if we take those to start with, the loads on the

2 thrust bearings, were the same as between each of the cones.

3 A. With all respect, I would have to state he would not actually

4 even think about loads per se but, rather, he would observe

5 wear and his intent would indeed be to try and even wear; but

6 loads per se, not having any method of determining,

7 calculating, those, all he really observes is wear.

8 Q. But he would understand that wear is caused by load?

9 A. That he would understand, yes.

…

16 Q. And he would appreciate that if there was an imbalance in the

17 wear on the thrust bearings, for example, that would be as

18 a result of an imbalance in the load on the thrust bearings.

19 A. He would have that intuitive knowledge, yes.

20 Q. Similarly, if he saw an imbalance in the wear on the journal

21 bearings, he would appreciate that that was because there was

22 an imbalance in the load of the journal bearings.

23 A. Possibly. There are other reasons for wear.

180. This exchange led to a prolonged sequence of questions and answers extending to page 390, in which Mr Hall first did not accept that the designer would make any connection between uneven wear and uneven loading but when shown his own witness statement containing a reference to overloading accepted that the skilled designer engaged in dull bit analysis would aim to balance loads by taking steps to equalize wear, but only to the threshold at which the wear was equal. Thereafter, he said, force imbalance could not matter because the skilled man could not observe it.
181. Rabia, which had been produced by Professor Cooper as exemplifying the common general knowledge has a chapter called Rotary Drilling Bits in which the following passage appears:

Design factors

The design of the various bit parts is largely dictated by the formation properties and size of hole. The three legs and journals are identical, but the shape and the distribution of cutters on the three cones differ. The design should also ensure that the three legs are equally loaded, to avoid the excessive loading of one leg only. The following factors are normally considered when designing and manufacturing of soft and hard three-cone bits: (a) journal angle; (b) amount of offset; (c) teeth; (d) bearings; and (e) interrelationship between (c) and (d).

Important bit nomenclature is presented in Figures 4.3 and 4.4.

Journal angle

The bit journal is the bearing load-carrying surface, as shown in Figures 4.5 and 4.6. The journal angle is defined as the angle formed by a line perpendicular to the axis of the journal and the axis of the bit. Figure 4.6 is a section through one leg of a three-cone bit. Angle θ in Figure 4.6 is the journal angle.

The magnitude of the journal angle directly affects the size of the cone. An increase in journal angle will result in a decrease in the basic angle of the cone and, in turn, cone size. Figure 4.7 shows how the cone size decreases as the journal angle increases from 0º to 45º. At a journal angle of 45° the cutters can theoretically become truly rolling.

The smaller the journal angle the greater the gouging and scraping action by the three cones….

182. This elementary text certainly suggests balancing the forces in the legs. This, of course, necessarily involves balancing the (bit) axial component of force on each cone (Hall transcript 396-8). Nonetheless, it is important not to read too much into it with the benefit of hindsight, since it does not explicitly distinguish the downforce from the other force components acting, as Professor Cooper acknowledged (transcript 1101):

10 Q. There is no dissection of the various forces and discussion as

11 to downforce as a pure force on its own?

12 A. That is true and therefore when I read that, I would say it

13 means that if we take the phrase "the three legs are equally

14 loaded" and that means that all the loads are essentially the

15 same as taken between cones, it is not restrictive into

16 bearings. It is not restrictive into forces on legs. It is

17 not restrictive as regards the direction of any of the forces

18 which may be on the bearings or the legs or the cones or

19 anything. It is a general statement that to the extent that

20 it is possible, my Lord, things should be balanced up.

183. It was common ground that if one equalizes the downforce on each cone one does not necessarily equalize the cone axial force, and vice versa. What Professor Cooper maintained was that you balanced what you could, and that it was standard engineering practice to do so.
184. Mr Hall's answer at 382 (above paragraph 178) was put to Professor Cooper

(transcript 1096) who took the view that it confused two questions, viz. would the designer consider that load imbalance caused wear, and what could he do about it, given that load could not be measured. He regarded the proposition that it was necessary to balance the downforce (WOB) between the cones as being (variously) so evident that it did not need to be mentioned and blindingly obvious (transcript 1122), providing the forces could be measured.

185. What is lacking here is any suggestion that it is part of the common general knowledge to set out to balance downforce in distinction from the other forces acting. The force on the cones, whatever it is, will conventionally be resolved into components along the cone axis and normal to it, but there is no suggestion that in equalizing forces on the thrust and roller bearings of the cones one is equalising downforce. The cones are not equal structures.
186. Professor Cooper also relied on the Reed lecture notes which are pleaded expressly against the patent. These include the rather bald statement that 'the designer tries to balance, or equalize the loads on each of the 3 cutters'. I am doubtful about the usefulness of this as a general statement, because again there is no clear explanation of how this result was achieved for downforce in the absence of any way of measuring it. I accept that balancing axial and transverse cone loads was common general knowledge, because everybody would understand that uneven dull bit wear was the result of unequal loading in these directions.
187. I think that the common general knowledge did extend to (1) an appreciation that WOB was a major component of the force acting on a bit (2) a general understanding that uneven wear was the consequence of out of balance forces (3) an understanding that the equalisation of wear involved the reduction of out of balance forces caused by imperfections in a particular cone and out of balance forces between each cone (4) a desire to balance bits overall, and this includes balancing the obvious forces, so far as possible, using the secondary indications that were provided by dull bits. I have changed my view on a number of occasions whether Professor Cooper's basic contention, that vertical load balancing is so obvious it does not need to be stated, is sufficient, the more so because if my personal knowledge had anything to do with it I would be disposed to agree with him. I do not think, however, the evidence really supports him taken as a whole. The effect of what I do consider to be common general knowledge on the skilled person's appreciation of the disclosures of the cited documents must be dealt with as each citation is considered.

The Ma Paper.

188. This is the paper referred to in the specification and which is relied on by Halliburton to patch up the disclosure so as to render it sufficient. Dr Huang, who is Director of R&D for Smith Bits and who is primarily responsible for the IDEAS software attended the trial. He gave unchallenged evidence that he wrote the first version of IDEAS from about mid-1996, before the priority date, basing it on the Ma Paper. Professor Ma was employed as a consultant by Smith and Dr Huang has access to the BRIAS software that is referred to in the paper. But that is by the way. The question is what Ma discloses.
189. Ma is concerned with simulating the interaction of a roller bit and rock, as its name suggests. The opening paragraph of the abstract summarises the disclosure:

'In this paper, the surface of each tooth of roller bits is represented by scores of points, whose 3-D compound coordinates are used to reflect the shape and size of the tooth. Thus the cutting structure of the bit together with their movement is represented by the time-sequence of the coordinates of the several thousand points. Hence, the computer simulates the roller bit.'

Ma's teaching is not straightforward, and the language gives difficulty from time to time, but what he provides is a scheme for simulating the action of the bit on the rock, and so the penetration of the bit into the rock. He describes the deficiencies of existing models in this way:

'Up to, now, however, all the bit's motion models, the interacting force models, the ROP and torque models of roller bits are obtained by simplifying the interaction between the bit and bottom hole. The major simplifications and suppositions are: (1) without any regard to the shape and size of the tooth by using a point or a line of the tooth; (2)'. Mistaking the compound motion of the tooth as vertical motion and . . regarding the force as proportional to the inserted depth; (3) Neglecting the bumps and craters and taking the bottom hole as a plane or smooth cones; (4) Regardless of the shape and size of craters and modelling only by a relation model. of the crater volume with the inserted depth; (5) Neglecting the differences among the contacting teeth and thinking that each has the same interacting force with the bottom hole and breaks the same volume of rock.

Although these models revised by fitting the field data or the experiment data and have some values of applications after being, yet their scopes of application are very limited. In particular, they can not reflect the effect of subtle changes of bit structures such as the shape and size of the tooth, the cone offset, the shape of cones and the arrangement of teeth on cones, on the bit motion, the interacting force and the ROP.'

190. Ma starts by constructing a geometric model of bit and bottom. He is interested in three variables z, the penetration of the bit into the hole, the rotation angle of the cone f and the rotation of the bit θ. For the purpose of the analysis of the dynamics of the system, he divides the tooth surface into a mesh of points defining the structure of the tooth, and the bottom of the hole is similarly divided into a mesh of points. He defines successive bottom holes as being the results of the disintegration of the previous bottom hole effected in a time .t. Each such bottom hole is expressed as a mesh of points from which the shape of the next will be computed.
191. In his discussion of the interaction of the tooth with the rock, Ma sets out his two equations (8) which are similar to equation (1) of the patent, though expressed in terms of a single tooth, not an element of a tooth, and making no assumption as to whether the forces are linear with vertical and lateral penetration: F_v = k_vS_vh_v ^q1 and the corresponding equation for lateral force show that Ma contemplates a general relationship, with the values of the key constants k and q being properties of the rock and thus obtained by experiment. There was some attempt to show that this data is something that would be obtained from a bit designer, but these are obviously experimentally derived data, as Professor Newland made clear (transcript 874-5). He describes the different modes of breaking the rock in detail and describes a model for the crater produced by the insertion of the tooth into the rock. When he comes to consider the interaction of the bit and the rock he starts with 'the part of the WOB suffered by each contacting tooth'.
192. Ignoring a small term representing the acceleration of the bit body in the hole axial direction (Ma calls this the Z axis) he points out that the WOB is given by the sum of the forces in contact with the rock summed over each cone, and expresses it in his equation (15) WOB WOB(t) = " : this is a sum of the force acting on each tooth
(index k) in contact over each row (j) over each cone (i). Fv is the vertical component of the force on each tooth (tooth k in row j on cone i) and thus he can define his model: the correct distance for the bit to move into the formation in each incremental rotation or time interval (there is no difference since it is assumed that the bit RPM is constant) is that for which all the forces acting on all the teeth in contact with the rock are equal to the weight on the bit.
193. Finally, Ma shows how cone and bit speed are related in his equations 16 and 17, which again depend on an experimental determination of the frictional torque on a cone. He does not compute the torque from his model of the interaction of the tooth and the rock. He puts the various models together into a simulation that he describes on page 6 to give the following information about the bit:

'(1)The position of the bit cutting structure and the relative position of the teeth in space.

(2)The shape and size of the bottom hole and the well bore.

(3)The interacting factors such as the contacting teeth of the bit, the number of the contacting teeth, the inserted depth of each tooth, the shape and size of the inserted part of each tooth.

(4 )The size and direction of each interacting force.

(5)The shape and size of a crater by any contacting tooth.

(6)The torque of the bit and the size and direction of the resultant lateral force.

(7)The deviation and the lateral displacement of the bit.'

194. As Ma puts it, the interaction between rock and bit is a stable random process, and he shows that it is possible to average the variables he has identified over time. The purpose of the model is to examine the effect of the bit structure, rock properties and WOB on the ROP. In his conclusion, he observes that the model as implemented in a program called BRIAS provides information that can be used to evaluate the bit structured designed and to guide the bit design. As he puts it:

'Compared with the conventional methods (design, manufacture, test and repeating the circle), to develop a new type of roller bit, this software can save a lot of expenses and time.'

195. The disclosure is thus of a model, admitted by Halliburton to be capable of being made by the skilled person, providing this capability. Although it is a force-based model, what the article does not disclose is any particular force-related criterion or criteria by which the designer should be guided, other than ROP. Neither claims 1 nor 3 can be invalidated for obviousness unless it can be shown that the common general knowledge of the skilled team would enable them gladly to take the simulation and use it to observe two parameters of the bit in particular: volume removal and axial load balance. There is nothing about volume removal, and there is a clear disclosure of a simulation in which all relevant forces can be observed, and averaged.
196. So the question is whether it is obvious to use this model to balance the vertical forces on each cone. The crucial part of the evidence for this purpose is in the crossexamination of Mr Hall at transcript 637 line 23 to 646 line 8. The case put is clear enough: to balance the vertical load on the legs, which is largely WOB, using Ma's model to help, is obvious. Mr Hall's principal answer is that it was not obvious to set out to balance the vertical forces on the legs. I have to say that Mr Hall's objections to the adequacy of the force balancing patent compared to Ma, particularly on the matter of bit/cone speed ratio, where he seized on Mr Kitchin's use of the word 'bearing' in connection with the reference in Ma to friction, were very unconvincing reasons for not using Ma to provide the model. The problem is the obviousness of the criterion. Mr Hall rejected it (638 line 8).
197. Professor Cooper took a rather more general engineering approach. Anything out of balance should be balanced, but he accepted (rightly, I think) that there was no teaching of equalizing downforces on the cones to be found in Ma.
198. In this state of things, unless I am satisfied that it was obvious to the notional team from the common general knowledge that equalizing downforces should be one of the criteria for a successful design, and hence to be aimed at (with other things) in a design the allegation of obviousness in the light of this document must fail. I think it does fail. I am very sensitive to the contention that no engineer will willingly design anything that is out of balance, and also that designers were very conscious of drillstring oscillation, which would neceessarily be sensitive to out of balance conditions at the bit. But drill bits are not symmetrical structures, and I am not satisfied on the evidence that to use equality of downforces as a design criterion was obvious.

Sandvik

199. This is a paper appearing in the South African Mining and Engineering Journal in 1979. It discloses the existence of a computer program used by Sandvik in an iterative design process. It is in the nature of 'advertorial', but its disclosure matters. The important parts of the disclosure are (a) the desirability of making the three cones carry an equal share of the 'feed force', i.e. the WOB (page 2 column 1 fourth paragraph) and (b) the use of a computer model to model the forces on the cones and so equalize the load on the bearings (page 2 column 3):

'In view of bearing loads it would therefore be desirable to have a bit with the same button pattern on all rollers. Each roller would then absorb the same amount of the feed force and all three rollers would be subjected to the same bearing toad But the demand for the largest possible rollers can be better met by provision of different button patterns. '

200. Mr Hall accepted that this implicitly explained to the reader that it was desirable that the same feed force is applied to each of the cones. This gives point to the second significant part of the disclosure:

'In redesigns and new designs of roller bits it has proved necessary already on the drawing board to get some idea of the force balance on the bit, both that among the three rollers and that between individual bearings in anyone roller. This is done in a miniature computer of type PDP 11 by means of two simulation programmes specially prepared for roller bits. The FORTRAN programming language is used for this purpose. There is naturally an effort to achieve as good an agreement as possible between the simulation models and the bearing force measurements on the rig. The most difficult thing with the models is to describe as correctly as possible the play of forces between the cemented carbide button and the rock, how great the force is, in which direction it works, etc.

In order to get an idea of the magnitude of the bearing forces and their variation during rotation of the rollers, the bearing forces were previously projected on the drawing board geometrically for each 15º which the roller was turned. This was a time-consuming method and it took several weeks to draw one's way through the three rollers on a bit.

The corresponding work can now be performed in a few minutes with the aid of a computer. Today, it takes five minutes to calculate interval moves of 5º on the three rollers of a 250mm bit,. In this way a large number of alternative solutions can be calculated in order to arrive at the alternative which best satisfies the stipulated requirements.'

201. Mr Hall suggested that the only purpose of the simulation, as described, was to provide information relating to per-cone bearing forces, and that it did not suggest that the downforce on each bearing was simulated, notwithstanding the reference in the first quotation that I have set out above. He did not accept that to equalize bearing forces was the same thing as equalizing downforce on each cone, and that it followed that there was disclosure of a design criterion (if I may summarise) relevant to the claims. So far as Mr Hall was concerned, the disclosure was insufficiently definite.
202. There are two objections to Sandvik. The first is that it is merely suggestive as to the equalization of downforces, rather than clear, and disclosures of this sort are likely to take on a disproportionate significance when read with the benefit of 20/20 hindsight. The second is that it is not an enabling disclosure, in the sense that the skilled man would be confronted with serious, and possibly impossible, difficulties if called on to employ its teaching at the priority date (the relevant date for obviousness). Once the irrelevant and repetitive aspects of the disclosure of the patent are shorn away, it discloses little more than Sandvik, but in my judgment one thing it does clearly disclose is the use of downforce on cones as an equalization objective. I do accept that Sandvik, like the patent, is not enabling. However, I agree with Smith that Sandvik does teach the desirability of equalizing downforces on the individual cones, as well as equalizing cone axial force. This does not render the patent obvious, since the method of creating a computer program at the priority date would be just as difficult as I consider implementing the invention of the patent would have been. So this allegation fails.

Soviet patent 1691497 'Tricone drill bit'

203. Again this document stresses equalisation of the bearing load in a three-cone roller bit. The teaching may be taken from the abstract on the first page: 'drill bit operation provides an equal distribution of the load on all bearings by means of the rows breaking up circular bottomhole areas that are identical in area.'
204. The way this is achieved in the design described is to establish critical ratios which are derived using an analysis involving the equalization of volume removed by the rows on each cone. I think that Mr Hall accepted that such a bit could be made (Transcript 743). Such a bit must fall within claim 7, since the volumes removed by the bit would be balanced.
205. Rather oddly, it is said that in the patent's own terms this means claim 6 is also invalid, having regard to the unchallenged teaching that volume balance involves load balance. I have construed claims 6 and 7 prima facie to permit the evidence of a simulation to demonstrate infringement. Since this bit cannot be simulated, and since there is no information about its behaviour in different formations, in some of which it may be balanced, in others not, it is not possible to decide whether the claim is obvious or not.
206. I am unimpressed by the other arguments erected on the basis of this disclosure. While some form of iterative design may necessarily be involved, the properties of the formation are not taken into account in the described method. While it may be obvious to do this in principle, no way of doing it is disclosed.

The Composite Catalog and the Reed lecture

207. These documents can be dealt with quickly. The only disclosure in the Composite Catalog relied on is a statement that two designs of bits disclosed 'utilize cone points on each of their cones. This feature balances the weight distribution between the three cutters and provides maximum total bit-bearing life.' My impression was that Professor Cooper was really employing this citation to corroborate his contention that it was common general knowledge that weight on the cones should be balanced. I am not persuaded. In other words, it adds nothing to an allegation that the patent is obvious in the light of the common general knowledge. The Reed lecture is in the same category for the reasons I have give in considering the common general knowledge above (paragraph 185 above).

'NOT AN INVENTION'

208. To be patentable, any invention must satisfy what appear to be two requirements: it must be capable of industrial application (section 1(1)(c)) and it must not consist of subject matter excluded by subsections (2) and (3) of section 1 of the 1977 Act. Subsection (3), which is concerned with inventions contrary to public policy or morality (these are the words current at the application date: they have now changed) need not be considered.
209. The words 'capable of industrial application' are explained, without being defined, in section 4:

'4.—(1) Subject to subsection (2) below, an invention shall be taken to be capable of industrial application if it can be made or used in any kind of industry, including agriculture.

(2) an invention of a method of treatment of the human or animal body by surgery or therapy or of diagnosis practised on the human or animal body shall not be taken to be capable of industrial application.

(3) Subsection (2) above shall not prevent a product consisting of a substance or composition being treated as capable of industrial application merely because it is invented for use in any such method.'

210. So far, so good: the invention of claims 1 and 3 is clearly capable of industrial application, since it can be used in the production of drill bits. But it is said that it falls within the specifically enumerated heads of exclusion in subsection 1(2). These are—

'(a) a discovery, scientific theory or mathematical method;

(b) a literary, dramatic, musical or artistic work or any other aesthetic creation whatsoever;

(c) a scheme, rule or method for performing a mental act, playing a game or doing business, or a program for a computer;

(d) the presentation of information;

but the foregoing provision shall prevent anything from being treated as an invention for the purposes of this Act only to the extent that a patent or application for a patent relates to that thing as such.'

211. Subsection 130(7) declares that these provisions (among others) 'are so framed as to have, so nearly as practicable, the same effects in the United Kingdom as the corresponding provisions of the European Patent Convention…have…'. This being so, it is a pity that the draftsman did not follow the same scheme as that contained in the EPC, which rather associates the specific exclusions with industrial applicability, but redrafted it and announced his version meant the same thing:

Article 52

Patentable inventions

...1) European patents shall be granted for any inventions which are susceptible of industrial application, which are new and which involve an inventive step.

(2) The following in particular shall not be regarded as inventions within the meaning of paragraph 1:

(a) discoveries, scientific theories and mathematical methods;

(b) aesthetic creations;

(c) schemes, rules and methods for performing mental acts, playing games or doing business, and programs for computers;

(d) presentations of information

…

(3) The provisions of paragraph 2 shall exclude patentability of the subject-matter or activities referred to in that provision only to the extent to which a European patent application or European patent relates to such subject-matter or activities as such.

212. The importance of the programmed computer in modern industry, and more recently the frequent attempts to push the envelope in the area of business methods, has ensured that there is a substantial body of cases in the Technical Boards of Appeal of the EPO relating to these two exclusions in particular. Discoveries and scientific theories have never given any difficulty, I suppose because it is difficult to work out how to draft a claim to either, but the scope and meaning of the other provisions is difficult.
213. It is idle to pretend that it is easy to reconcile the different cases on these questions, but part of the difficulty, I think, is caused by an unspoken belief that the various excluded matters have something in common. In my view, they do not. They are a heterogeneous collection, some of which (aesthetic creations) have their own form of protection, others of which (discoveries, mathematical methods and scientific theories) have never been accepted as suitable subjects of monopolies on obvious, but different, policy grounds. The problems are really caused by (c) and (d), which, by reason of their exclusion 'only to the extent that the patent relates to such subjectmatter… as such' are remarkably difficult to assess in cases lying near the boundary, particularly as it is difficult to discern an underlying policy. For example, do we only exclude computer programs as such because computer programs as such are protected by copyright, like aesthetic creations which can likewise be used industrially? Or is there some other reason? Whatever the reason, surely it is not the same as the reason for excluding methods of doing business?
214. In the United States, the problem has been solved by allowing just about everything to be patentable subject matter. While this solves the problem, it cannot be an answer, as anyone who has looked at some of the results will agree. The majority of the English decisions (in particular, Merrill Lynch [1989] RPC 561 (CA), Fujitsu [1996] RPC 511 (Jacob J) and [1997] RPC 608 (CA), Gale [1991] RPC 305), along with EPO decisions such as T 208/84 VICOM/Computer related invention [1987] EPOR 74 support a 'contribution' approach. What has the inventor contributed to the art as a matter of substance? Does it lie in excluded matter, or does it amount to a 'technical' contribution or effect? The contribution is considered as a matter of substance so as to avoid patents for novel programs on compact discs, for example, although this is an area in which the EPO appear to have wobbled: see T 0935/97 IBM/Computer Program Product II where a technical effect was found in the computer into which the program would be loaded from the claimed carrier.
215. In Fujitsu, as in many other cases, the claims were directed both to a method of using a piece of hardware, in the form of a programmed computer, and to the piece of hardware programmed to carry out the method. The purpose of the invention was to display crystalline structure of compounds in a novel way. Jacob J considered that the claims did not relate to a computer program as such, but, having regard to the method itself, were claims to a method of performing a mental act. The Court of Appeal held that they did not escape objection on the ground that they related as a matter of substance to a computer program as such, but were also objectionable on the second ground.
216. I am very reluctant to examine a large number of decided cases on this question, since for my purposes I think the law is, as I have indicated, clear, albeit difficult to apply: the contribution the inventor makes must lie in a technical effect, and not merely in excluded subject matter. But it is suggested that this case is on all fours with T 0453/91 IBM/Method for physical VLSI-chip design. In this case, the Technical Board of Appeal considered the VICOM case (above) and evidently felt unease with its distinction between a method of processing resulting in an image transformed in a defined way (not allowable) with a method of processing physical data corresponding to a physical entity (allowable). The case was concerned with a claim to a method that delivered 'a mere "design" in form of an image of something which does not exist in the real world and which may or may not become a real object'. The object in question was a Very Large Scale Integrated circuit, so there was no doubt that the claim was to a stage in manufacturing the chip, but the Board considered the claim rightly rejected. They allowed a claim to a method of making a chip in which the only features were the excluded method and the words 'and materially producing the chip so designed'.
217. I have great sympathy with this approach. An untethered method claim may well cover activities which have nothing to do with any industrial activity, but, if the claim is tied down to the industrial activity it becomes a valuable invention restricted to its proper sphere. What cannot be plausibly suggested is that the method is not freighted with the technical effect that is needed for patentability: but the scope of the claim should be restricted to its technical field.
218. In the present case, claims 1 and 3 are directed purely to the intellectual content of a design process, and the criteria according to which decisions on the way to a design are made. They are not limited in terms to a computer program, although no doubt are so limited as a matter of reality. They are thus firmly within the forbidden region as schemes for performing a mental act. So I think that these claims are bad because they are too broad, but an amendment of the type described in T 0453/91 should dispose of the problem.
219. It might be supposed that such amendment does not affect the position 'as a matter of substance', but I think this is quite wrong. The objection, in my view, is to width of claim alone when the method has potential industrial utility, that is, a potential technical effect. The objection to the claims in this case are to the form of the claim, not to the substance of the invention.

THE ORIENTATION PATENT

220. European Patent (UK) 1 117 894 B1 claims priority from 31 August 1998 and was granted on 3 December 2003. Its title is "Roller-cone bits, Drilling methods, and design methods with optimization of tooth orientation". It has only three claims, again claims to a method of designing a roller-cone bit, and claim 1 only is said to possess inventive subject matter. It is as follows (I have labelled the steps for ease of reference):

'1. A method of designing a roller cone bit, comprising the steps of:

(a) adjusting the orientation of at least one tooth on a cone, in dependence on an expected trajectory of said tooth through formation material at the cutting face, in dependence on an estimated ratio of cone rotation to bit rotation;

(b) recalculating said ratio, if the location of any row of teeth on said cone changes during optimization;

(c) recalculating the trajectory of said tooth in accordance with a recalculated value of said cone speed; and

(d) adjusting the orientation of said tooth again in accordance with a recalculated value of said tooth trajectory.'

221. We are again concerned with a method of designing a roller cone bit, employing the result of a simulation to fix the orientation of a tooth which is chisel-shaped or otherwise asymmetric with respect to the cone on which it resides. Of the seven 'Background' sections of the specification, five appear in the Force Balancing patent (Rotary Drilling, Drill String Oscillation, Roller Cone Bit Design, Tooth Design and Rock Mechanics and Formation, the last under the title Optimal Drilling with Various Formation Types) and I have already discussed them.
222. In the section entitled 'Background: Bit Design' paragraphs [0021] and [0022] (acknowledged to be common general knowledge) deal in general terms with the problem of tracking (that is rows, particularly the gauge row following in the footsteps of another row which may well cause fluctuations in the cone rotational speed).
223. At paragraph [0023], the specification develops the general statements in the preceding section somewhat and deals with the shortcomings of existing bit designs. This paragraph was accepted by Mr Hall as representing the common general knowledge of a bit designer, who would thus be aware of the orientation of the teeth in some designs with a view to increasing bottom hole coverage. The emphasis is again tracking. The acknowledgment of existing computer models for the hole bottom is dismissive.
224. Paragraphs [0021] – [0023] provide the only real description at this stage in the specification of the problem which the invention is intended to solve.
225. The trajectories which are referred to are the paths of the teeth across the bottom of the hole. These paths are not planar, because the bit is constantly advancing, and they are not circular, because the cone axis may be offset with respect to the axis of the bit so that it either leads or lags. Paragraph [0024] explains that software which graphically displays the 'linearized' trajectory of each tooth row (i.e. its planar projection in a plane approximating the hole bottom) and the translation of that trajectory onto the surface of the cone is desireable, but that approximations are nonetheless useful in the design process. It is said (paragraph [0029]) that the described methods provide a number of advantages:

(a) A very convenient way for designers to take full advantage of a computerimplemented calculation of geometries. (The motion over hole bottom of roller cone bit teeth is so complex that only a complex mathematical model and associated computer program can provide accurate design support.)

(b) Convenient calculation of tooth trajectory over the hole bottom during the period when the tooth engages into and disengages from the formation.

(c) The disclosed methods permit the orientation angle of teeth in all rows to be accurately determined based on the tooth trajectory.

(d) The disclosed methods permit the influence of tooth orientation changes on bit coverage ratio over the hole bottom to be accurately estimated and compensated.

(e) The disclosed methods also permit designers to optimally select different types of teeth for different rows, based on the tooth trajectory.

226. Paragraph [0030] contains a passage relied on as a cross-reference to the Force- Balancing patent application. Like the corresponding passage in that patent, it suggests that the Force Balancing patent application discloses 'methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application'. Again, I cannot see that this incorporates the disclosure of the Force Balancing patent application by reference. Additionally, for the reasons set out in Annex A the reference is insufficient to make the document identifiable at the relevant date.
227. The detailed description of the preferred embodiments follows. This part of the specification provides the detailed disclosure that has to be examined in deciding whether the specification is, as Smith allege, insufficient. A number of preliminary points should be made. First, paragraphs [0052] to [0063] can be ignored. Although they start in a promising way, they have nothing to do with tooth orientation and trajectory as such, and it was not suggested that they formed a material part of the disclosure. Mr Watson and Mr Hall agreed that they 'had nothing to do with the methodology of the patent as a whole or in the purported invention claimed.' They are, as the defendants submitted, a complete distraction.
228. Second, in considering the disclosure of this part of the patent, it is helpful to consider that the defendants' basic contention is that the disclosure is vacuous, in that it discusses the problem at so high a level of abstraction that it provides no assistance to the skilled man in actually constructing the 'complex mathematical model' (paragraph 224(a) above) that is needed before the claimed technique can be employed in the design of a bit. Where the disclosure is not free of useful content, the defendants say it is erroneous and wrong.
229. The disclosure is of a sample embodiment in which figure 1A shows an overview of the design process, while figures 1B and 1C expand on specific parts of that process. These figures are in the form of flow diagrams, and among other things they show (1) links to flows (A) and (B) in the 'overview' diagram A, (2) three different stop places (3) obvious entries from flow (B) in figure 1C and from flow (A) in figure 1B, although 1A is supposed to be an overview. The diagrams are difficult to interpret, and their interpretation is not assisted by paragraphs [0035] and [0036] which are obscure. The three obvious loops over teeth, rows and cones are not explained at all being merely described as counting. Remarkably, it was suggested to Professor Newland in cross-examination that the correct interpretation of figures 1A, 1B and 1C was not what the specification said (transcript 998):

15 MR. BURKILL: Professor, I think the outcome of all this, and this

16 may be a slightly shocking proposal, is that actually pages 13

17 and 14 are the wrong way round and that the way to make sense

18 of it is that if the calculation proceeds with the full

19 simulation on page 14 first and then uses page 13 in order to

20 generate the figures ----

230. After an intervention from me, and a development of the question, Professor Newland gave this answer at page 1000:

6 A. I agree that from an engineering point of view the procedure

7 by which you, first of all, run the full simulation for such

8 a length of time as is required to establish steady cutting.

9 From that simulation, you withdraw information on cone to bit

10 speed ratios and rate of penetration, probably averaged, and

11 that is not I think mentioned, but it would seem to me to be

12 sensible to average them, and then separately put that

13 information on cone to bit speed ratios into a kinematical

14 calculation which generates an initial bottom hole plot like

15 that in figures 3A, B, C and D from which the tooth

16 orientation could be decided. That I think is indeed

17 a logical explanation, but of course it is different from what

18 the flow diagrams show.

19 Q. Yes, I accept it requires cutting and pasting to transpose

20 pages 13 and 14, but from an engineering point of view, that

21 would actually be the way of achieving the figures at 3A, 3B,

22 3C and 3D. Is that right?

23 A. That would be one way of sorting out the position. There may

24 be others.

231. I cannot take this as what the document discloses to the skilled man. It had occurred to nobody until this question was put, and Professor Newland had been critical of the diagrams. He said he understood what the patent was aiming at (page 973):

14 A. Well, my Lord, what I think is this. If we were starting from

15 scratch, we would have to read in the bit parameters, the

16 geometrical parameters, and the positions and details of the

17 teeth. We would then have to feed in the known angular rate

18 of bit rotation and details about the formation properties,

19 then start the kinematical calculation, which would tell the

20 computer which teeth are above and immediately adjacent to the

21 formation at the starting position so they would have to

22 establish the start position.

23 Then the time[s] stepping process would begin. As I tried

24 to describe this morning, each time set would be made.

25 A balance would be sought between upforces and downforces and

2 cone to bit speed ratios would be subjected to updating

3 according to the torsional statement of Newton's laws. This

4 process would be established to get dynamical equilibrium in

5 what is happening so that the drill is now in actual .... Of

6 course the weight on bit would have been specified. The drill

7 is now in the simulation, drilling steadily down into the

8 formation.

9 At that point, the cone to bit speed ratios would be

10 drawn out and averaged over the period of 10 seconds, or

11 however much is agreed, and then the bottomhole plane would be

12 constructed for the average trajectories with the average

13 properties for that motion; so it would then be a bottomhole

14 plane picture from which the teeth could be oriented whenever

15 required. The optimization would have to be built into this,

16 so it would then look at the results that have been achieved,

17 whether they be forces or volumes, or some other parameter,

18 and compare them with an objective requirement and would say,

19 "If not met, change one or more parameters, go back to the

20 beginning and run the whole simulation again."

232. Moving on, the specification turns in five successive sections to the specifics of the geometrical description of the bit. It points to the use of four sets of coordinates, fixed with respect to each tooth, each cone, the bit and the hole. It is helpful to read this from Professor Newland's cross-examination between pages 1002 and 1051 of the transcript. In what follows, I have drawn heavily on the professor's answers, which were not challenged effectively.
233. A small, but not unimportant, point arises in relation to paragraph [0040] and its corresponding figure 14. While the coordinates shown (Hc, Rc, θc and .c) are sufficient to describe the position of a tooth on the surface of the cone and the orientation of the tooth axis with respect of the axis of the cone, if the tooth is itself capable of orientation (that is, it has a chisel end) a further quantity, an angle, is required fully to specify the position and orientation of the tooth. The professor called it a and drew a picture of it (X6). I found this entirely convincing. The challenge to the professor's view was ill-conceived and it follows that figure 14 of the patent, which is described in paragraph [0039] and employed in paragraph [0045] is erroneous. The matrix referred to in paragraph [0045] in fact must depend also upon the tooth orientation angle, which I shall again call a for convenience. It may be (it is not entirely clear) that the author of the specification has in fact proposed an approximation in paragraph [0044] that enables him to ignore the angle a for this purpose, at least, but I do not understand how this could work for the reverse transformation of paragraph [0051].
234. If we take the coordinate system for an individual tooth, we see that while the tooth will be described by a fixed set of points in this system and in the cone coordinate system^[12], those points are moving in the bit coordinate system, in a manner broadly determined by the cone/bit speed ratio and in the hole coordinate system in a manner broadly determined by the cone/bit speed ratio and the rotation of the bit. In order to construct a simulation, it is necessary to be able to move between these systems of coordinates. Two of them depend on time (cone to bit and bit to hole) and one is fixed (tooth to cone). The process of moving between systems of coordinates is called a coordinate transformation, and the specification describes coordinate transformations in paragraphs [0043] to [0048].
235. Rtc, the tooth to cone coordinate transformation is a fixed rotation and translation for each tooth. The expression as given is incomplete because the transformation between tooth and cone involves a rotation, so it should look like the expressions for Rcone and Rbh with a per-tooth translation element in the transform as at column 12 line 9.
236. Of course, the cone is rotating with respect to the bit, and so its transformation will contain an angle (it is called λ in the text) which is changing with time, and this rotation will be about an axis which may be represented by a vector in the bit coordinate system. It is called Nc. The transformation into the cone coordinate system is complex, and is represented by what is called the rotation tensor, which is set out at [0046] and called Rcone accompanied by a translation (column 12 line 9). This is a general expression: the actual terms of the transformation, which are hidden in the Nc and Mc, are not stated and must be worked out. This is not easy.
237. What the modeller will ultimately wish to see is a simulation of the pattern caused by the teeth on the hole bottom. So there is a third transformation, bit to hole. This again involves the rotation tensor, called Rbh, but also a term which depends upon the penetration of the bit. This transformation depends (among other things) on the constantly increasing angle ß. Again, the actual transformation is not given. Moreover, the scheme set out in the patent is oversimplified, because the orientation of the tooth in space must still be ascertainable in bit coordinates, and that means that Mb and Mc in the expressions for Rcone and Rbh cannot be 3×3 matrices but must have a higher order. Professor Newland volunteered that he had worked the correct expressions out. He said that working out the whole was 'a good master's degree project'.
238. It is clear, I think, that the transformations involve two angles. λ, the angle through which a cone has rotated, is the sum of all the steps through which it has rotated in the intervals of time Δt. ß, the angle through which the bit has rotated, is equally the sum of all the steps through which the bit has rotated in those time intervals. ß and λ are, of course, linked by the cone/bit speed ratio. If the model is to be useful, the angle through which the cone has rotated in time has to be determined by the angle through which the bit as a whole has rotated, and unless the ratio can be calculated (or assumed) the model will not be any use.
239. The specification then turns to the calculation of the trajectories of the teeth in the bottomhole plane. What is described in paragraphs [0049] and [0050] is purely the kinematic construction involved in determining what path in space (the trajectory) the tooth will leave in the plane of the hole bottom, for a given cone/bit speed ratio. It is not very explicit, but the solution to this problem involves knowing when the teeth enter and leave the formation, which is not properly dealt with at all in the Force Balancing patent, or here. Paragraph [0051] describes a projection of the trajectory seen in the hole coordinate system (the coordinate system in which it is sensible to visualise the trajectory) back onto the cone. This enables the designer to orientate the long edge of the tooth normal to the trajectory (soft formation) or collinear with the trajectory (harder formation) in the cone coordinate system and can thus be seen directly as a rotation of the tooth in its socket in the cone. For reasons that I shall discuss when considering the allegations of insufficiency raised against this specification, the information provided in paragraph [0051] is on one reading actually wrong.
240. The availability of the cone/bit speed ratio is essential to enabling the visualisation of tooth trajectory to which the specification relates. There is a brief passage in the specification that it is convenient to set out in its entirety:

Calculation of Cone/Bit Rotation Ratio [0069]

The present application also teaches that the ratio between the rotational speeds of cone and bit can be easily checked in the context of the detailed force calculations described above simply by calculating the torques about the cone axis If these torques sum to zero (at a given ratio of cone and bit speed) then the given ratio is correct if not an iterative calculation can be per- formed to find the value of this ratio.

[0070] However it should be noted that the exact calculation of the torque on the cones is dependent on use of a solid body tooth model as described above rather than a mere point approximation.

[0071] Previous simulations of roller cone bits have assumed that the gage row is the 'driving" row which has no tangential slippage against the cutting face However this is a simplification which is not completely accurate. Accurate calculation of the ratio of cone speed to bit speed shows that it is almost never correct if mul- tiple rows of teeth are present to assume that the gage row is the driver.

[0072] Changes in the tooth orientation angle will not themselves have a large immediate effect on the cone speed ratio However the tooth orientation affects the width of uncut rings and excessive uncut ring width can require the spacing of tooth rows to be changed Any changes in the spacing of tooth rows will probably affect the cone speed ratio.

241. The question is what 'detailed force calculations' have been 'described above'. I have described all the relevant passages in the specification, and no such calculations are described, although the purely kinematic calculations for depicting the movement of the tooth in space are all at least referred to, even if they are not referred to accurately and not set out explicitly.
242. Everything is lacking: there is no description of the interaction between the bit and the rock: there is no description of how to construct a model of the rotating bit in formation that will provide a cone/bit speed ratio. Even what I have found to be the insufficient description of the Force Balancing patent is nowhere to be found. This raises the immediate question of what the invention is actually for.
243. Reverting for a moment to the passage quoted above, the same goes for the 'solid body tooth model'. No 'solid body tooth model' is described, although one of the figures, figure 13, does show a tooth tip, unaccompanied by any description.
244. In my judgment, what is disclosed in this patent is a technique intended to be ancillary to a system for simulating a bit rotating in formation. This explains, among other things, the reference to graphical display of the hole-bottom pattern. It also explains why the core of the simulation in Figure 1C is described like this:

'Calculating cutting depth, area, volume and forces for each [tooth] in cutting, Updating the hole bottom matrices based on the crater model for rocking being [drilled]. [Counting] the number of teeth […] cutting for cones and bit [in] any time step. Projecting the teeth force into cone and bit coordinates and getting the total cone and bit forces and moments. Calculating the specific energy for the bit.'

245. As a description of how an undoubtedly complex model works, this is useless. But as a description of what a model will actually be doing, it is at least explicable. Column 10 lines 1 to 8 merely repeat this passage without enlarging on it in any way and no method of actually constructing the model is cross-referenced. I conclude that this patent is really concerned with a sort of bolt-on accessory, or additional feature, for a simulation system that is not described. This box was indeed referred to in the crossexamination of Professor Newland as calling for a 'Ma kind of simulation', a proposition with which he agreed. It is to be noted, however, that this patent contains no cross-reference to the Ma Paper, and the Ma document that is referred to was not relied on as a relevant cross-reference.

Construction of the claim.

246. I set the claim out again for convenience:

'A method of designing a roller-cone bit, comprising the steps of:

(a) adjusting the orientation of at least one tooth on a cone, in dependence on an expected trajectory of said tooth through formation material at the cutting face, in dependence of an estimated ratio of cone rotation to bit rotation;

(b) recalculating said ratio, if the location of any row of teeth on said cone changes during optimization;

(c) recalculating the trajectory of said tooth in accordance with a recalculated value of said cone speed; and

(d) adjusting the orientation of said tooth again, in accordance with a recalculated value of said tooth trajectory.'

247. The problem that has worried me is whether steps (b), (c) and (d) have to be performed if the location of no row of teeth changes during optimization. I think the answer ought to be yes, and the reason lies in the word 'optimization'. It is clear, I think, from the specification read as a whole that the adjustment of tooth orientation is to be carried out with other adjustments during the bit design process. Those referred to include width of uncut rings (paragraph [0064]) and interference between cones (paragraph [0065]) but these are really geometrical problems. Paragraph [0066] is much more general. What orientation is intended to do is to affect the interaction of the tooth with the rock, and so the dynamics of the system. Absent any other considerations I would have concluded that the invention only relates to, and the claim can only be infringed by, systems in which the cone/bit speed ratio can be recalculated, not re-estimated,^[13] and accurate calculation of this quantity (i.e. capable of showing the tooth in approximately the right place after however many rotations are simulated) is essential. It was also accepted by Mr Hall that cone/bit speed ratio was affected by rate of penetration, ROP. Accordingly, a dynamic model would have to be constructed in which changes in design variables that affected ROP, which is after all what they are primarily directed to, would involve a recalculation of the kinematics of the system, including the cone/bit speed ratio.
248. Of course, this simple view is disrupted by claim 2. There is a presumption, not a particularly strong one, that claims form a hierarchy having ever-decreasing scope, and the natural inference one would draw from claim 2 is that claim 1 covers cases in which there is no recalculation, a view which derives considerable support from paragraph [0072] (quoted above paragraph 239). Faced with these two factors, I think my preferred view of this document is untenable, and I accept that if during an optimisation the row position does not change, the claim does not require further calculation. The claim reduces to covering, in this case, a way of visualizing the tooth orientation with respect to its simulated trajectory on the hole bottom, the designer being able to set the orientation with respect to this simulated trajectory.
249. In opening Halliburton's view was different both from the above interpretation and from that I prefer, but in reply they express a preference for the construction that I would prefer were it not for claim 2 and paragraph [0072]. That is, steps (b), (c) and (d) are never optional, moving a row is merely an example of the sort of thing that can be done during optimisation, and should be glossed to mean 'any optimisation at all'. I have given my reasons for reluctantly rejecting this contention. I say no more about Halliburton's original construction.

INFRINGEMENT

250. I have considered the general matters ('directly obtained by') above. No special point arises in respect of this patent.
251. There are two bit designs only alleged to infringe this patent. These are the McDonough bit and the Singh/Twist bit (paragraph 118 above).
252. IDEAS contains a so-called crater display or bottom hole plot (PPD figure 33, which looks astonishingly like the image in the Ma book figure 3-11). It does not display a 'trajectory' output. Oddly, Mr Hall did not accept that this plot could be used to orientate the teeth based on trajectory, but Smith maintain the contrary, as they must if they are to be consistent with the Ma book. There is also an animation of the bottom hole plot. It is therefore necessary to demonstrate, as a minimum, that the designers (1) twisted the teeth and (2) did so in reliance on the bottom hole plot, or its animation.
253. So far as Mr McDonough is concerned, there is no real evidence that he used the crater plot during his design. The claimants rely heavily upon an answer that he gave to an ambiguous question at transcript 1232, which was asked immediately after I had considered it necessary to stop Mr Watson to break the questions up. 4 MR. WATSON: Yes. (To the witness) Throughout the design 5 process, when you were changing the orientation of teeth, you 13 The distinction between estimation and calculation is clearly drawn by the claim.

6 looked at the various outputs that are referred to in 10 and

7 11. Is that correct?

8 A. I most likely would have, yes.

254. The 'various outputs referred to in 10 and 11' is a reference to the witness's statement:

'10. I cannot remember exactly what 1 looked at in lDEAS when I designed this cutting structure. However, I would have looked at the "insert" output for each row of each cone in the analysis phase of IDEAS because the teeth on my design were oriented. Although I cannot remember doing so, I would have probably attempted to ensure that the red areas (indicating contact with the formation) were not concentrated in one small area on the output, by rotating the tooth to ensure that contact with the formation was distributed across as much of the tooth as possible.

11. I may also have viewed the 'bottom hole plot' and the 'animation' design tools within IDEAS. The animation tool shows the cutting structure design in rotation, and can assist in detecting gross design issues and errors in the design process. For example, if I had made a mistake in translating my design from Pro/E to IDEAS that mistake could be quickly detected by looking at the animation. Predominantly, this would be my reason for pulling up the animation window. This window also allows the user to visualize occurrences of tracking. However, it would require the user to watch the simulation with a close eye throughout the entirety of the simulation in order to understand whether a tooth is tracking often enough to warrant alteration, so I did not think it was the best means for detecting tracking and altering tooth orientation. I would not have used the animation window to alter tooth orientation on my design. The bottom hole plot can also be used to detect tracking but is not very useful for determining tooth orientation. If tracking were to occur on one or more of the rows, then a pitch break may have been added to prevent this from happening. I would have relied upon the "insert" output as means for altering tooth orientation. I say this because the "insert" output is more or less a summary of all the occurrences of contact with the simulated formation of all the teeth for a given row.

12. During the design process I would also have looked at the Fz_Aver information for each of the rows and cones as I changed the crest length, orientation, location and/or crest width of the milled teeth, so that I could see how my changes were affecting the ratio of cone load to bit load. This is a difficult task as, more often than not, a design yielding a faster ROP would also yield more unbalanced cones. It is a general assumption by bit designers that if you distribute the forces acting on each cone disproportionately, then one of the bearings of the bit may fail sooner than if they all took the same load. Therefore, I always like to try to get the milled tooth bits that I design to be as close to being balanced as I can manage, while still taking into account the need for as fast an ROP as possible. '

255. Mr McDonough undoubtedly varied the twist of the teeth in a row during the design process, which may have lasted between 10 and 50 iterations. His evidence is that he primarily used the 'insert' output for tooth orientation. This evidence, and the evidence he gave in cross-examination, fails, in my view, to establish what the claim requires, which is to adjust the orientation in dependence upon trajectory. I reject the submission that Mr McDonough looked at all the outputs at every adjustment, which is how the claimants wish me to view his answer.
256. Mr Singh based his adjustments on ROP and scraping distance. Since scraping distance must, so Halliburton submit, depend upon trajectory, then Mr Singh must have adjusted his tooth orientation in reliance upon trajectory. This is hopeless. A trajectory is not a distance, it is a direction and a distance. The need for the direction is so that you can set your tooth across the direction or at an angle to it. If you do not do this, you do not infringe. It never began to be shown that in fact the scraping distance was in some way derived from a trajectory, although Dr Huang, who was intimately acquainted with the software, gave evidence and could have been asked.
257. This patent is not infringed.

VALIDITY—INSUFFICIENCY

258. Although the claim covers the simple system I have described in paragraph 247 above, the specification must be sufficient in respect of alternatives that the claim explicitly covers. It is no good being sufficient in respect of part (a) of the claim, if there is no guidance about how to put the invention into effect if a row has to be moved in consequence of the optimization process. The evidence on the issue of modelling came only from Professor Newland. Although Halliburton had nominated an expert to deal with modelling issues, they did not call him.
259. The pleaded case is as follows:

'The Patent provides no or no sufficient disclosure as to how to perform the recited adjustments: how to determine or recalculate the expected trajectory or the relative positions of the bit and formation that would be required; how to estimate or recalculated the recited ratio of cone rotation to bit rotation; how to determine the cone speed; or how to account for the physical aspects of drilling into a formation in particular how to determine and apply the physical properties of the formation and/or the bit.'

260. Smith rely upon the following matters:

(a) the errors and difficulties in Figs 1A-1C;

(b) the need to calculate the transformation matrices required for the kinematic calculations, including ascertaining that the equations given contain errors and correcting them;

(c) the lack of a force model, which must be created from scratch; if a crossreference to the Force Balancing Patent is permissible as Halliburton suggests, the skilled person must also deal with the incorrect description of the force model as a single element model, and the other inadequacies of the Force Balancing patent, including the need to develop experiments to obtain data from real life; this would involve designing and building the specialist equipment needed and thereafter carrying out all the required experiments;

(d) the calculation of the cone to bit speed ratio;

(e) the failure to take account of the shape of the tooth on the P1 – P2 line in cone coordinates and its effect on the calculated line of trajectory;

(f) alternatively to (e): the failure to mention or describe the different transformation of the trajectory from hole coordinates to cone coordinates.

261. In my judgment, each of the above objections, with the possible exception of the point about the transformations, is well founded, for the reasons that I have given in discussing the disclosure of the document above. I should, however, explain my reasons in more detail.
262. Figures 1A-C. The first insufficiency arises in the description of the preferred embodiment, but it is the only disclosure of a manner of implementing the invention. It is plainly wrong, and it was not, I think, suggested that the skilled person would both appreciate the error and know how to correct it: indeed, when Mr Burkill QC suggested his possible approach during the cross-examination of Professor Newland, it was a novelty. This militates against the error in these figures being anything other than the sort of error which gives the addressee of the specification an unfair burden.
263. The Transformations. I have already discussed these in the context of the Force Balancing patent. I remain uneasy about the insufficiency of the actual transforms, notwithstanding the errors in them. I accept Professor Newland's assessment that the implementation of the kinematics would be a good project for a master's degree, but, as he said, this is an implementation problem, and not research. I have already indicated that in computer-implemented graphics a high level of understanding of coordinate transforms is really a prerequisite, and I am not satisfied that the addressee of this specification would not have the requisite skills. On the other hand there is great force in the contention that the basic description of the problem is incorrect, in that the angle that I have called a is omitted, and that if the patent is to avoid a finding of insufficiency I should be satisfied that the description, such as it is, would not mislead. The defendants have a point when they observe that although it is clear that this angle needs to be defined, the cross-examination directed to showing the contrary rather indicates that its absence may not be obvious to the skilled person.
264. I am also very sympathetic to the contention that the algebra of the transformations could have been shown and has not been. It is certainly set out in the Ma Book and the Ma paper.
265. I am of the view that the real problem here is, again, with the cone/bit speed ratio and with the absence of an adequate force model. Halliburton appear to submit that the disclosure of paragraph [0069] is sufficient even if there is no cross-reference to the Force Balancing patent. I find nothing to support this. There is no disclosure of any 'detailed force calculations' and there are no hints in the specification as to how these calculations might be carried out. Every passage in evidence upon which the claimants rely either relates to technique (such as the torque balancing technique) or to references that are not legitimate in the context of this disclosure (the Ma Paper, the Force Balancing patent). Nowhere is it explained how the forces acting may be quantified. I regard this disclosure as plainly insufficient in this regard. My observations about the sufficiency of the rock-bit computer model in the context of the Force Balancing patent apply here with additional force, the disclosure being effectively non-existent.
266. If the Force Balancing patent is incorporated by reference, there is still no sufficient disclosure. The disclosure of the Ma paper at least is required for a proper force model, albeit one inconsistent in certain respects with the model referred to in the Force Balancing patent.
267. Halliburton submitted in closing that it was possible to arrive at a cone/bit speed ratio by balancing torques as follows (paragraph 145 of their closing skeleton on insufficiency):

'Mr Hall's evidence on torque balance was at Hall I para 34, and Hall II paras 70, 75 and 77. He was XX'd on Day 3 at 439 et seq., more especially from 451. The thrust of his evidence was that:

Rate of penetration and cone speed are interrelated.

You solve for them by an iterative process.

You would initially assume an advance for the bit, and iterate on that to find the rate of penetration.

Thereafter, having that, you iterate on torque balancing to check the cone speed. o If necessary, you then go back and iterate penetration again.

As to this, see passages starting at 456/15, 457/12, and at 460:'

268. I quote this merely because although I am not confident that I entirely understand it I do not believe that the quoted passages in the evidence can support it. Mr Hall's evidence was clear that it was necessary to calculate forces to find the torque. At page 457, he said this:

12 Q. We have assumed an ROP and a cone to bit speed ratio.

13 A. We determine an ROP or a penetration. You would assume an

14 advance for the bit. You would have to then calculate what

15 forces that would produce, balance those off against the

16 weight on bit to determine if they were correct, and you would

17 have to iterate first on the degree of advance.

18 Q. The ROP cannot be determined entirely by a static test

19 involving simply omitting the bit to rest on top of the rock.

20 A. That is correct.

21 Q. One is inevitably making an assumption about the ROP and the

22 cone to bit speed ratio when one does this exercise of

23 determining the forces on movement and thereafter assessing

24 whether it talks about the cone axes amount to 0 or not.

25 A. Yes.

269. This issue comes back to the difficulties which I have felt on the proper approach to this claim. But it does not matter, because I think that the apparent significance of the failure to take account of ROP was accepted by Halliburton, who attempted to show, by reference to X8, a 1969 paper, that cone speed (ie cone angular velocity) did not much affect rate of penetration. This was, in my view, a misreading of the paper, which is concerned with the velocity of the tooth on contact with the formation. Force on the cone will be affected by the rate at which teeth are entering and leaving the formation and the path that the teeth follow in the formation, including the rate at which they are gouging through it, which of course does depend upon cone angular velocity. This suggestion was convincingly rejected by Professor Newland, and had never been suggested by Mr Hall in his evidence.
270. It should again be noted in this connection that it was failure to come up with a model giving a satisfactory cone/bit speed ratio after some years' work that induced Hughes Christensen to abandon their simulation. This is one indication from the real world of the difficulty that constructing an adequate force model actually causes.
271. For the reason I have attempted to give there is an insufficient disclosure of any method of calculating forces.
272. The engagement and disengagement points. This point arises on "back projection" referred to in paragraph [0051] of the specification (paragraph 238). Professor Newland said he took weeks to see it. It is a problem of coordinate systems. As the patent says, the designer wants to visualize the entry and leaving points of the tooth in a fixed coordinate system, the hole bottom. If the designer orientates his tooth having regard to the trajectory of the tooth between these points, he wants to be able to translate the tooth orientation that he has selected back into cone coordinates. The suggestion the patent gives is to back project the hole bottom trajectory onto the surface of the cone, and rotate the tooth with respect to that line, but the mathematics given is wrong. The line identified by the patent is not the projection of the trajectory onto the surface of the cone. This must be what the specification is talking about but, as described, it is not. Professor Newland explained this and I attempted to summarise it:

5 MR. JUSTICE PUMFREY: Yes, of course. Do I understand you to be

6 saying therefore that if I sit there fondly imagining that

7 what I have been doing is looking at the trajectory as

8 projected on to the bottomhole plot, and if I thought that

9 what the patent was talking about was orientating the tooth so

10 as -- let us be normal -- to get maximum scraping effect to

11 the trajectory on the bottomhole plot, I would have got it

12 seriously wrong, because, as I understand your evidence, what

13 in fact you feel the author is telling you to do is to look at

14 that line as it appears in cone coordinates effectively on the

15 surface of the cone therefore and projected on to the surface

16 of the cone so that I will find notionally on my cone a nice

17 line drawn through the tooth, and when I find that line drawn

18 through the tooth, I twist my tooth until it is normal to that

19 line projected on to the surface of the cone. Have I

20 understood your evidence correctly?

21 A. Yes, my Lord, you have. That I understand to be the

22 invention.

23 Q. And the line that is projected on to the surface of the cone

24 is the projection of a straight line in space joining the

25 entry and exit points in cone coordinates. Is that also

2 correct?

3 A. It is a straight line on the surface of the cone. P1 may

4 not ----

5 Q. Straight line on the surface of the cone?

6 A. That is the way in which it is expressed. It is a line in

7 3-dimensional space. You are absolutely correct, my Lord; it

8 is curved, but it is approximated in the calculation I gave in

9 my appendix as a straight line.

10 Q. It is the point joining the entry and exit points in cone

11 space in a space on the surface of the cone.

12 A. Yes. To be precise, it has to pass through the cone surface

13 in order to join P1 and P2.

273. What is contended is that the patent actually fails to describe the mathematics of this correctly because it does so in terms of 'the engage and disengage points in the cone coordinate system'. The projection of the trajectory of the tooth onto the cone is not related to 'the engage and disengage points in the cone coordinate system' because in the cone coordinate system these are not going to be spaced apart by more than the width of a tooth. This can be seen immediately by considering a sharp-pointed tooth (a mathematical construct, not a real tooth) whose entry and exit points in cone coordinates are identically the same, even if it is scraping. An observer sitting on the cone will see the hole bottom rotating round the cone and periodically dropping on to a tooth, being scraped, and lifting off again. While it may tilt a bit, the entry and exit points in cone coordinates will not depend on the length of the scrape and not on the direction of the scrape either.
274. This raises a short point on construction. In paragraph [0051], are P1 and P2 the endpoints of the trajectory projected onto the cone and expressed in cone coordinates, or are they literally the engage and disengage points in the cone coordinate system of a tooth? In the latter case Rs is pretty small, and λs likely to be poorly defined. The better view, I think, is that the passage is not to be read literally, which is certainly unusual in a purely mathematical discussion. The problem then becomes how one carries out the necessary projection. This is undefined. It is not a reverse transformation because that will transform the trajectory back into a line lying within the compass of the single tooth.
275. Halliburton say that none of this matters, because what paragraph [0051] is talking about is the tooth crest, and the engagement and disengagement of the tooth crest point. If this is right, of course, Professor Newland's point is made for him, provided that the crucial words relate to the engagement and disengagement points expressed in cone coordinates. Mr Hall did not refer to the relevance of the tooth crest, agreed that Professor Newland's diagram at bundle 10.2[10] was a possible result of reading the patent, and accepted that the shape of the tooth would affect the position of P1 and P2. Incidentally, Mr Hall's evidence in respect of Professor Newland's paragraphs 249 to 255 was remarkably slow, and his apparent failure to understand figure B2 after study I thought was unimpressive.
276. Halliburton rely heavily on an answer given by Mr Hall at page 481, which I quote with its context:

15 Q. Mr. Burkill suggested, as I understood him during the course

16 of his submissions to my Lord, that this point was simply

17 addressed by having a single crest point.

18 A. Yes.

19 Q. But that is not an answer, is it, Mr. Hall, because if P1

20 equals P2, then there is no pair of points between which

21 a line can be drawn to determine the trajectory?

22 A. Not so. It is not at all so. In fact, actually using one

23 single point is what I would probably guide my modeller to do.

24 The reason for that is, as I stated first, P1 and P2 are

25 two points on the hole bottom initially, not on a cone. So if

2 you have a tooth with a point, it will begin contact with

3 a hole bottom in a location, but due to the scraping and

4 gouging and traversing, it will leave contact at a different

5 location. If I now take a snapshot of that entry and exit

6 point and project it on to my cone coordinates system, it is

7 not a single point. It is a path. It is not one single

8 point. It was caused by one single point on the cone, but it

9 is not a result of one single point in the formation. In

10 fact, tracking one single point would seem to be a totally

11 reasonable modelling approach, which is what I would likely

12 guide my modeller to do to remove this sort of possibility.

13 Q. With great respect, this is simply inconsistent. What you are

14 suggesting, Mr. Hall, is inconsistent with what is described

15 in paragraph 51 because P1 and P2 are different points in cone

16 coordinates.

17 A. Once they have been transposed into the cone coordinates.

18 They initiated as an entry point and exit point, however, in

19 the formation. They are then transposed to cone coordinates.

277. In other words, Mr Hall's approach does require some form of projection of the notional trajectory onto the cone. He accepted that a simple reverse transformation could not be performed (transcript 486) and hypothesised a reverse transformation that was not time dependent (transcript 487), thereby recognising the problem to which I have referred in paragraph 273 above. No such transformation is hinted at or described.
278. So paragraph [0051] may be right when it talks about projections, but unclear when it says what the endpoints of the projected trajectory are and entirely unclear about how to perform the projection. Where is the cone to be when the projection is performed? One assumes that it has to be positioned so that the projected trajectory lies over the tooth in question even though the simulated tooth will have rolled past. This is entirely avoidable ambiguity. It deceived Professor Newland. In other words, paragraph [0051] is faulty and obscure, and for that reason insufficient.
279. In summary, insufficiency of the disclosure of this specification is established. While I have expressed some doubt as to the matter of the transforms, the rest of the enumerated problems would be enough taken singly to establish insufficiency. Cumulatively they render this specification seriously unclear and incomplete in its disclosure of the invention. I do not believe that the skilled person could perform this invention with the information this document provides.

VALIDITY—OBVIOUSNESS

280. My findings on sufficiency mean that it is open to the defendants to show that the concept of the invention is obvious and enabled by a single publication. But because the patent is insufficient, it is to the highest degree unlikely that a prior publication, not enabling in itself, can render the patent obvious when considered with the common general knowledge. It is important that a logical gap does not open between the objections of anticipation and obviousness.
281. The inventive concept of the Orientation patent was identified in opening in this way by Halliburton:

'156. As already stated above, the invention is based on an underlying realisation that the motion of the bit can and should be modelled mathematically. If the cone/bit rotation speed can be found, then the motion of the cones and teeth can be established. From that, the actual trajectory of the tooth through the formation can be determined.

157. The invention provides that the tooth orientation may then be adjusted by reference to its trajectory. If [when] the location of a row changes during the design process, a new trajectory is established, which is in dependence on a recalculated estimate of the cone/bit speed ratio and this new trajectory is used as the basis for a further orientation of the tooth.

282. This was effectively accepted by Mr Hall (main report paragraph 36). I shall approach the allegation on this basis, because it does not affect the obviousness case, which does not depend upon the wider construction, at least so far as I am concerned.

The Ma Book

283. The Ma Book is a very comprehensive work. Chapter 3, which describes Ma's kinematic model of a bit, and chapter 6, which descries his 'New Methodology for the Rock Bit Design' are of particular importance. The book itself describes 10 years' work. The evidence is that it provides a bit designer with a possible approach to designing drill bits.
284. Section 3.5 is concerned with 'the track of teeth on the bottom-hole and the lateral scraping of bit'.^[14] Ma presents an algorithm (figure 3-12) for calculating the track of teeth on the bottom hole (illustrated in figure 3-11). Lines 12-13 of this algorithm show the calculation of the rotation of each cone (φi) by multiplying the bit rotation (θi) by the cone/bit speed ratio, which, as stated, is a constant and is not recalculated.
285. On page 231 in section 6.1.2.1, Ma devotes a passage to the determination of the cone/bit speed ratio (the 'ratio of roller and bit speed'). His preferred method is plainly to measure them, but, if not, to use the simulation program. In Section 6.1.2.2 he describes the preliminary design, observing that 'the diagram of the tooth track and the comprehensive block diagram of the bottomhole coverage assist the designer to arrange the cutting structure more reasonably'. He continues:

'the patented program for optimizing the tooth (or insert) crest direction has great interest for the bit designer, manufacturer and user. If the tooth or insert is not symmetrical about its own center line, its crest is in a certain direction. This direction has considerable effect on the scraping area and the rock breaking effectiveness of the bit. This direction, however, was formerly always along the generatrix [i.e. parallel to the axis] of the roller cone, until the new type of bit was designed by the author's research group. The ROP of these bits with the optimised tooth deflection angle are much improved in the field tests.'

286. Section 6.1.2.3 discusses an iterative design process using the simulation. After the qualities of the formation are measured,

'our computer simulation program combines all the necessary data runs all the teeth of bit step by step and predicts the ROB, the sidecutting ability and wearability for specific bit-formation set. If the results are not fully satisfactory, the related factors will be adjusted and the optimum design will be approached step by step.'

287. There were some things Ma's model could not do. It could not predict the change of cone/bit speed ratio with cone offset, from which I infer that cone offset was not a design parameter which could be varied in his simulation. But taking the document as a whole it is remarkably coy about the calculation of cone/bit speed ratio.
288. Halliburton sensibly accepted that Ma includes the following disclosures:

(a) Calculating the tooth trajectory based on a cone/bit speed ratio.

(b) Using the trajectory so calculated to orientate the teeth.

They insist, however, that there is no disclosure of an iterative recalculation of the cone/bit speed ratio. In this they are right. I should say, however, that I consider a recalculation of the cone/bit speed ratio every time the design changes as an obvious thing to do, if the change to the design might change it.

289. It seems to me that feature (a) of the claim is accordingly obvious. So far as features (b), (c) and (d) are concerned, the patent and Ma share the difficulty that if they know how to calculate cone/bit speed ratio, which foxed Hughes Christensen, they are not telling. Ma simply tells the reader to use his program: but the program he discloses does not calculate cone/bit speed ratio, but takes it as a constant. It may be that Ma is also talking about interpolating experimental results, but this is not calculation for the purposes of the claim. This calculation is an obvious desideratum, but evidently difficult to realise. Ma reinforces my views of the insufficiency of the patent so far as the calculation of cone/bit speed ratio is concerned. Ma could not do it either.

US 5,197,555 (Estes)

290. The patent called Estes does not call for separate consideration. It too says nothing about how to do the necessary calculations, although it clearly teaches that teeth should be orientated with respect to their trajectory. The idea is obvious, but the skilled reader is left in the dark about how to perform the calculation. If the Orientation patent were sufficient, this patent would not affect its validity, because none of the calculations required forms part of the common general knowledge. In this respect, it is not enabling.

VALIDITY—NOT A PATENTABLE INVENTION

291. I repeat my observations in respect of the Force Balancing patent. There is no material distinction between the two for this purpose.

SUMMARY OF CONCLUSIONS

292. Both patents are invalid in their entirety for insufficiency. If they had not been insufficient, both patents would probably have survived the attack of obviousness made upon them. At present, both patents cover unpatentable subject matter, but I envisage that this defect could be cured by amendment, were it not for the insufficiency of the disclosure, which I do not believe can be cured in this way. The Force Balancing patent would, if valid, have been infringed to the extent I have indicated. The Orientation patent would not have been infringed. The action must be dismissed. The counterclaim succeeds. I will hear submissions on the form of the order.

Annex A—cross references

293. The passages in the patent applications said to amount to cross references are as follows (Orientation patent first):

"[0030] The following patent application describes roller-cone drill bit design methods and optimizations which can be used separately from or in synergistic combination with the methods disclosed in the present application. That application which has common ownership inventorship and effective filing date with the present application is Application no._____ filed 31 August 1999 entitled "Force Balanced Roller Cone Bits Systems Drilling Methods and Design Methods" (atty. docket no. SC-9825), claiming priority from U.S. provisional application no 60/098 466 filed 31 August 1998. That nonprovisional application, and its provisional priority application, are both hereby incorporated by reference."

"[0037] U.S. Patent Application____, filed 31 August 1999 (issued as US patent 6,095,262), entitled "Roller-Cone Bits, Systems, Drilling Methods, and Design Methods with Optimisation of Tooth Orientation" (Atty. Docket No. SC-98-26), and claiming priority from U.S. Provisional Application 60/098442 filed 31 August 1998, describes roller cone drill bit design methods and optimizations which can be used separately from or synergistic combination with the methods disclosed in the present application. That application has common ownership, inventorship, and effective filing date with the present application. and its provisional priority application, are both incorporated herein by reference."

294. I express the view above that the words used in the published patents are insufficient to incorporate the disclosure of the cross-referred documents. Smith go further, and say that the words do not sufficiently identify any document and even had the words been otherwise adequate to their purpose would not have been effective.
295. There is no doubt that in domestic law the date for assessing sufficiency is the date of application (Biogen v Medeva [1997] RPC 1). The office (be it the EPO or the UK office) has the duty to examine the sufficiency of the disclosure, and it could not be otherwise. Alternatively, it is conceivable that there may be two relevant dates: the cross-referred material must be (a) accessible to the examining office at the date of application and (b) accessible to the public at the date of publication. This is the EPO's view, as expressed in the Guidelines for Examination (part C, Chapter II, paragraph 4.18):

(ii) if the reference document was not available to the public on the date of filing of the application, it can only be considered if (see T 737/90, not published in OJ):

(a) a copy of the document was available to the EPO on or before the date of filing of the application; and

(b) the document was made available to the public no later than on the date of publication of the application under Art. 93 (e.g. by being present in the application dossier and therefore made public under Art. 128(4)).

296. The applications on which these patents were granted were PCT applications and therefore have a deemed date of publication by virtue of Article 158(1) of the EPC, which is the date of publication by WIPO.

(1) Publication under Article 21 of the Cooperation Treaty of an international application for which the European Patent Office is a designated Office shall … take the place of the publication of a European patent application and shall be mentioned in the European Patent Bulletin…

297. If, therefore, the cross-referenced documents were not available to the public on the date of publication of the PCT applications, then on a view of the law most favourable to the claimants they were not successfully incorporated by reference. Both PCT applications were applied for on 31 August 1999 and published on 9 March 2000.
298. The cross-referenced documents can, with the benefit of hindsight, now be identified, but the identification is ambiguous. In respect of the Orientation patent, the reference may be to the PCT application for the Force Balancing patent, or it may be to another application, the domestic US application filed under the same attorney docket number on the same day. The US application was not published until the corresponding US patent was granted (10 April 2001 for 6,213,225, the Force Balancing patent). The USPTO does not publish applications before grant, when the public side of the file is opened, and accordingly some publication of the cross-referred documents must be found elsewhere.
299. The cross-reference in the Force Balancing patent is less ambiguous. It is to a US application, which was not published until the corresponding patent was published. Halliburton say that the right answer is the corresponding PCT application, which does not bear the docket number under the heading 'Applicant's or agent's file reference'. I cannot accept this, even if the PCT application designated the US. A PCT application designating the US is not a US patent application. It merely has the same effect.
300. It seems to me to follow that these documents do not satisfy the EPO's requirements. In any event, they do not satisfy the requirements of Biogen, which is binding upon me. If the terms of the cross-references had otherwise been adequate, the documents were not available and the cross-references would have been ineffective.

Note 1   See for example the Smith advertising flyers at 24.2[22], [23], [25], [26] and [27].    [Back]

Note 2   Not Pleaded: exhibited by Professor Newland at 10.2[11].    [Back]

Note 3   Pleaded against this patent: ‘the Ma Paper’.    [Back]

Note 4   Transcript 384.    [Back]

Note 5    F is a vector, having both magnitude and direction and denoted by a bold capital. This is not the place for a discussion of vectors generally and a good explanation is given in the experts’ reports.    [Back]

Note 6   The whole of the number above the required precision is rounded off.    [Back]

Note 7   This is the one aspect of IDEAS not discussed in the PPD, but it does not seem to me that it matters    [Back]

Note 8   This is a reference to the Ma Book [Chapter 2]    [Back]

Note 9   Quoted above, paragraph 149    [Back]

Note 10   Save to ask Mr Singh whether he had written the acknowledgment of prior art in ’288 at col 4 line 9, which he hadn’t.    [Back]

Note 11   Windsurfing International v Tabur Marine [1985] RPC 59.    [Back]

Note 12   The tooth is fixed to the cone.    [Back]

Note 13   The distinction between estimation and calculation is clearly drawn by the claim.    [Back]

Note 14   Ma Dekun’s sometimes idiosyncratic English appears to be preserved in the book but causes little difficulty. The mathematics is clear.    [Back]