Obviousness
68 The issue of obviousness which arises in this case is whether a hypothetical person skilled in the relevant art in light of the common general knowledge as at 6 November 1995 would have regarded it as obvious, in the production of an improved wear assembly, to utilise a screw as a means of eliminating looseness in the wear assembly and thereby arrive at the claimed invention in Jones III: see s 7(2) of the Act; Lockwood Security Products Pty Limited v Doric Products Pty Limited (No. 2) (2007) 235 ALR 202 at 231. When addressing this question, the Court must be careful not to substitute its own deduction or perception for that of the hypothetical person. Furthermore, as the High Court has stated on several occasions, "[a] scintilla of invention remains sufficient in Australian law to support the validity of a patent": see Lockwood 235 ALR at 217 and cases cited therein.
69 The applicants contend that the person skilled in the relevant art in this case is someone who works in the earthmoving industries who would be involved in the design and manufacture of wear assemblies and therefore would be familiar with factors relevant to their design and development. It is said by the applicants that Professor Wightley is not a person skilled in the relevant art because he had no experience in the design, operation or manufacture of wear assemblies attached specifically to excavators.
70 The respondents' contention is that only Professor Wightley and Messrs Meyers, Ashworth and McClanahan are persons skilled in the relevant art. It is said that Professor Wightley is a mechanical engineer with extensive experience in design and manufacture of replacement wear parts for use in the mining industry generally; Mr Meyers is a mechanical engineer with experience in the design, manufacture, sale and maintenance of replaceable wear parts for excavators; and Messrs Ashworth and McClanahan are relevantly skilled mechanical engineers. On the other hand, say the respondents, Mr Alden, the expert called by the applicants, is a structural engineer, which means he is not skilled in the relevant art. In addition, the respondents argue that the only witness called by the applicants on the issue of obviousness was Mr McClanahan (the co-inventor of the patents), and that the evidence called by the respondents in relation to this point was therefore not directly challenged by any qualified expert.
71 In my opinion, Professor Wightley and the other mechanical engineers whose evidence was adduced by the respondents have sufficient expertise to express the opinions as persons skilled in the art. However, for reasons given below, I do not accept Professor Wightley's evidence and the respondents' submission that the solution provided by the invention in Jones II and Jones III was obvious.
72 The applicants say that the invention in this case is an improved wear assembly which is constituted by the combination of elements set out in claims 1 and 51 of Jones II and claim 1 of Jones III. Each of these claims in suit, it is said, involves a combination of elements in a way that constitutes a new inventive thing, despite the fact that each of the elements (other than the lock adjustment assembly) was contained in the Toplok shroud, which the applicants' properly acknowledged formed part of the common general knowledge. In simpler terms, the new combination achieved by the patents in this case provided a new benefit beyond what had previously been provided, and was therefore inventive.
73 The applicants submit that the invention the subject of Jones II and Jones III was based on perceptions that:
· the Toplok shroud provided a good foundation upon which to develop an improved wear assembly that could serve not only as a shroud but also as an adapter;
· the forces to which an adapter may be exposed could produce looseness in mounting of the wear assembly to a Toplok style of mounting; and
· this looseness could be overcome by an adjustment assembly that moved the relative positions of the bearing surfaces of the Toplok style lock so as to pull the wear assembly over the mount.
74 The applicants' argument is that the use of this type of adapter with a Toplok style of mounting was not part of the common general knowledge at the relevant date. Furthermore, the applicants say that, since there were at the relevant date many wear assemblies available to be used as the starting point to develop an improved assembly which overcame looseness between the wear member and the boss, the use of Toplok as the starting point was not required by any design principle, and was therefore not obvious. Indeed, as Professor Wightley acknowledged in cross-examination, even if an inventor were confined to the Toplok shroud as a starting point, there were several other locking methods known which may have been used instead of the method ultimately used in the invention. One such alternative method was the use of two piece pins, wedges and spools to take up any looseness in the wear assembly.
75 The applicants argue that the common general knowledge as at the priority date included not only a significant number of wear assemblies and wear parts used in the mining industries, but also a specific awareness of the use of the Toplok shroud and its locking mechanism. This awareness, it is said, extended to the way in which the Toplok shroud had a tendency to looseness and slippage, which was a consequence of its usage of cast parts, general wear and tear and the absence of any tightening mechanism. The applicants submit that the evidence of Professor Wightley on this point should not be accepted because (i) he was presented at the outset with both the details of the problem encountered by the Toplok design as well as the specifications for the patents in suit which solved the problem, meaning that his evidence is weakened by hindsight reasoning; and (ii) his conclusion that Toplok suffered from a "design flaw" referable to inherent looseness is erroneous. The applicants also argue that the alleged problems in relation to looseness, while known to a limited extent, were not part of the common general knowledge, a conclusion which is supported by the evidence of Messrs Ashworth and Meyers who said that they were unable to confirm whether they were aware of this problem at the relevant date. In addition, the applicants say that the weight of the evidence demonstrates that there is no reason to suppose that a hypothetical addressee, confronted with this problem of looseness, would come up with the invention the subject of Jones II and Jones III.
76 In relation to the criticism of the hindsight reasoning involved in Professor Wightley's evidence, the applicants say that a person skilled in the art would have attempted to understand the nature of the problem before attempting to formulate a solution. To do otherwise would risk confusing the exact nature of the problem to which the solution is sought. By engaging in hindsight reasoning, it is said, one cannot conclusively determine whether the solution is a response to a so-called "design flaw" in the existing art or as a response to, say, the excessively large forces which arise specifically in the case of large excavator buckets. In short, the applicants say, all other problems which may have given rise to the difficulty encountered by the Jones I design would need to be explored before ascertaining the cause of that difficulty and positing a solution. Professor Wightley, it is said, did not identify the precise cause and nature of the problem; rather, he was asked to assume that it existed, and as a consequence he did not consider solutions alternative to the one used by the inventors of Jones II and Jones III (such as the possibility that looseness could be overcome by adjusting tolerances or using shins or rails as temporary fixes). Accordingly, the applicants conclude, Professor Wightley's evidence is affected by hindsight reasoning and should not be accepted.
77 In answer, the respondents contend that detailed knowledge of Toplok, including knowledge of how it was assembled in the field and the problems of looseness from which it suffered, was common general knowledge as at the priority date. They directly dispute the perceptions on which the applicants say the invention in Jones II and Jones III was based. The respondents say that each of claims 1 and 51 of Jones II and claim 1 of Jones III was an obvious solution to a recognised problem in Toplok, and that if a person skilled in the art wished to provide a means for tightening the Toplok assembly, then such a person would be led directly as a matter of course to try a screw adjustment mechanism. The screw adjustment is said to have been a basic and practical measure which was well known to mechanical engineers as a way to tighten assemblies that needed to be made rigid. It was also, the respondents say, clear that the only practical way of introducing such an adjustment to Toplok was by providing a threaded aperture through the rigid lock, with a gap in the rear wall of the opening provided to allow the adjusting screw to pass through the wear member, thereby protecting it from abrasive material while still making it reasonably accessible.
78 The respondents rely largely on the opinion of Professor Wightley in relation to the issue of obviousness. His opinion was that, as at the priority date, it was common general knowledge amongst mechanical engineers that the Toplok shrouds experienced problems of looseness in the assembly due to problems arising from the design and dimensions of the assembly and abrasive wear. Professor Wightley also stated that the common general knowledge included knowledge of basic mechanical engineering principles and techniques relevant to the reduction of looseness in wear assemblies (by, for example, the use of take-up mechanisms such as a screw adjustment). Professor Wightley also described the inability to tighten the wear assembly in Toplok as a "design flaw", an opinion which (among others) the respondents deny is affected by any hindsight reasoning. Professor Wightley suggested that a mechanical engineer who wanted to overcome the looseness problem in Jones I, would readily appreciate that some mechanism to tighten the assembly was required and that one measure which would immediately come to mind would be the use of a screw adjustment to remove the looseness. He said that this was a simple and practical measure, routinely used by mechanical engineers to eliminate looseness where rigid assemblies are required, which was beneficial because it could be located towards the rear of the wear member away from abrasive material, was self locking, would not rattle loose, was inexpensive and was adjustable over its effective length.
79 Finally, the respondents also contend that, having regard to the dates of application and filing for United States Patent number 5,713,125 ("Hensley") and Jones II, which were in close proximity, the fact that Hensley independently arrived at the same invention at around the same time supports the respondents' argument on obviousness. This, it is said, is because such circumstances suggest that the very similar designs which are the subject of these two patents were not beyond the ordinary skills of the art at the relevant time.
80 It is also important in this case to note that when deciding whether there has been an inventive step the courts have attached considerable weight to the evidence of the inventor: see Terrell, The Law of Patents (3rd ed., 1994) at [5.92]. In this respect I give weight to the evidence of Mr McClanahan, who was one of the named inventors of Jones II and Jones III, that the solution of the adjustment assembly was not perceived by the inventors for some time until after about mid-1995. Mr McClanahan said that the skilled person would be unlikely to use a bolt and nut assembly because of expected problems such as rusting and deformation of the thread. He also stated that the looseness in Toplok was not a "design flaw" because that wear assembly was expressly designed to permit looseness, a design characteristic which could be tolerated in a shroud and which carried the advantage of being relatively cheap and simple to manufacture. In Mr McClanahan's view, the problems which arose in relation to Toplok were related chiefly to large buckets, and were often cured by a variety of methods which did not involve an adjustment mechanism such as the one which is included in Jones II and Jones III. This, says Mr McClanahan, along with the commercial success of the Toplok shroud, runs contrary to the suggestion that Jones I suffered from a design flaw. The fact that there were some problems does not necessarily indicate that there was a design flaw in the Toplok wear assembly.
81 The dangers inherent in drawing conclusions with the benefit of hindsight have been emphasised in the authorities. As Aickin J pointed out in Meyers Taylor Pty Ltd v Vicarr Industries Ltd (1977) 137 CLR 228 at 242:
'… subsequent analysis of an invention - "the dissection of the invention" - is not often helpful in resolving the question of obviousness. It has been criticized as being a mistaken approach, see Blanco White, Patents for Inventions, 4th ed. (1974), at par.4-214. This matter was also discussed by Menzies J in Commonwealth Industrial Gases Ltd. v M.W.A. Holdings Pty. Ltd. where he commented on the undesirability of analysis by hindsight because once one sees an invention it may very often appear very simple and one may then wonder why no one previously had thought of so simple an improvement device.'
82 The danger of hindsight was also referred to by Lord Diplock in Technograph Printed Circuits Ltd v Mills-Rockley (Electronics) Ltd [1972] RPC 346 at 362 (and approved by the High Court in Aktiebolaget Hässle v Alphapharm Pty Ltd (2002) 194 ALR 485 at 491) in these terms:
'Once an invention has been made it is generally possible to postulate a combination of steps by which the inventor might have arrived at the invention that he claims in his specification if he started from something that was already known. But it is only because the invention has been made and has proved successful that it is possible to postulate from what starting point and by what particular combination of steps the inventor could have arrived at his invention. It may be that taken in isolation none of the steps which it is now possible to postulate, if taken in isolation, appears to call for any inventive ingenuity. It is improbable that this reconstruction a posteriori represents the mental process by which the inventor in fact arrived at his invention, but, even if it were, inventive ingenuity lay in perceiving that the final result which it was the object of the inventor to achieve was attainable from the particular starting point and in his selection of the particular combination of steps which would lead to that result.
83 As can be understood from these comments, a posteriori reasoning, which starts with an understanding of the solution to a given problem and then seeks to draw a conclusion as to how obvious it was to reach that solution, has been correctly criticised by the Courts. Where both the problem and the solution are put before a person from the outset, it becomes a simpler task to reason backwards from solution to problem, which may lead that person to draw an incorrect or flawed conclusion as to obviousness of the solution.
84 To a large extent it is common ground that there were problems in the operation of Toplok. As to the extent to which those problems were known at the priority date, while I accept that it was common general knowledge among mechanical engineers that problems arising as a result of looseness between the different parts of the wear assembly could be reduced by the use of adjustment assemblies (such as a screw adjustment), I cannot go further and accept Professor Wightley's evidence that it would be readily apparent to a mechanical engineer considering the problems in the Jones I design that the use of a screw adjustment would be an obvious solution. Professor Wightley's evidence must be approached with some caution because he was simultaneously informed of both the nature of the problem encountered by the Jones I design and also the solution ultimately supplied by the patentee in this case. Having been shown all of Jones I, Jones II and Jones III at the time he was instructed, Professor Wightley was aware of the solution at the time he was asked to express his opinion about its obviousness, which in my view reduces the weight of his evidence on this point.
85 The difficulty with both the problem and its solution being presented to Professor Wightley as part of his instructions was that he did not seek to identify the causes of the problem because there was no need to do so. Although Professor Wightley may have been able to go beyond his instructions and investigate this issue independently, he understandably did not do so. As a consequence of these circumstances, Professor Wightley did not consider any possible alternative solutions. His instructions were only to comment on the obviousness or otherwise of the threaded adjustment set out in the patent, which meant that he did not consider the possibility that looseness of wear members could be overcome by adjusting tolerances or using rails or shins which were adopted as temporary fixes.
86 In addition, I am not persuaded that Professor Wightley was correct in describing the problems arsing from looseness in the Toplok product as being a "design flaw". Although the evidence could be understood to establish that some recurrent difficulties plagued the usage of Toplok, it did not go so far as to establish the existence of a design flaw in Jones I. The problems regarding looseness were problems which arose from the increase in size of the buckets in specific instances, and these problems were alleviated by a variety of practical means which did not involve any adjustment mechanism. There was also evidence that considerable numbers of the Toplok shrouds had been sold and that they had some commercial success. In such a context, a conclusion that the inventive step in Jones II and Jones III was obvious cannot, in my view, be sustained.
87 On balance, I find that the evidence given on behalf of the respondents by Professor Wightley in relation to obviousness is reduced in weight by hindsight assumptions relating to the nature of the problem, the need for a new design and the solution ultimately developed. I do not accept that the problems associated with Jones I admitted of an obvious solution which would have been readily perceived as a matter of course by a person skilled in the art at the relevant time. In my view, the identification of the problem encountered by Jones I and the solutions proposed by Jones II and Jones III involved considerable inventive thought. Accordingly, I find that the respondents have not established that the move to the wear assembly locking device in Jones II and Jones III was an obvious solution to a person skilled in the art having regard to the common general knowledge at 6 November 1995.