CONCLUSIONS ON THE APPEAL IN RESPECT OF AP 664820, AS 692882 AND AS 698806
81 It will first be necessary to explain further how issue on this aspect was joined in the argument on the appeal.
82 As we followed the parties' respective arguments, there was little, if any, disagreement about the general principles to be applied by us.
83 In particular, it appears to be common ground that a purposive construction of a claim may be adopted (see, e.g. Azuko Pty Ltd v Old Digger Pty Ltd, above, at [31] - [36], [66] - [67], [100] - [101], [163] - [165] and the cases there cited (SLR by High Court on the ground of insufficient prospects of success on appeal (2002) 6 Leg Rep SL 3); see also Grove Hill Pty Ltd v Great Western Corporation Pty Ltd [2002] FCAFC 183 per Gyles J at [300] - [302]).
84 At the same time, as we followed their arguments, the parties would accept, as a correct statement of general principle, the observations of Dixon J in Walker v Alemite Corporation (1933) 49 CLR 643 at 657 as follows:
"The thing claimed is not the mechanical embodiment of a new principle. It is not a particular application of some inventive idea which may be applied to produce the same new result in other ways. It describes and claims an appliance of definite construction exhibiting specified features in combination. The claim to protection ex facie appears to be based upon the association of these features so as to produce the useful result. The question is not whether the differences of construction in the respondent's nipple and in that of the appellant are material to the utility of the appliance or to the manner of performing its function or whether ingenuity is involved in the changes. The question is: How wide is the monopoly? Once it is determined that the discarded features are essential to the claim, the substitution of other means of performing the like function cannot amount to infringement by colourable variation, or by the use of a mere mechanical equivalent. The changes are not insubstantial variations in detail under colour of which the thing claimed is taken. They are not other mechanical embodiments of the inventive idea for which protection has been obtained. The claim itself makes them cardinal. The intention of the appellant to take advantage of the narrowness of the monopoly is, of course, immaterial."
85 It seems also to be common ground that expert evidence can be admitted on the construction of the claims, so as to place the Court in the same position as the skilled addressee. However, as Gyles J noted in Grove Hill, above (at [306]), the use of such evidence upon an issue of infringement, at least in the case of a mechanical device (as here) does not go very much further, as it is primarily admitted to explain the features of the alleged infringing article, and how it works.
86 It further appears to be common ground that, in ascertaining the width of a particular claim, whilst it is not permissible to vary or qualify the plain and unambiguous meaning of the claim by reference to the body of the specification, yet if an expression in a claim is not clear, it is permissible to resort to the body of the specification to define or clarify the meaning of the words used in the claim (see Interlego, above, at 478 - 479; Rehm Pty Ltd v Webster's Security Systems (International) Pty Ltd (1988) 81 ALR 79 per Gummow J at 91).
87 Another area of apparent common ground is the advantage enjoyed by a trial judge in this kind of litigation (see, e.g. S W Hart & Co Pty Ltd v Edwards Hot Water Systems (1985) 159 CLR 467 at 478, 491). As Gyles J observed in Azuko, above (at [152]), apart from seeing the witnesses, including the expert witnesses, the trial judge is educated in the issues, including the technical issues, in a comprehensive and orderly fashion which is difficult, if not impossible, to recreate on appeal, even where, as here, the question is, to a large extent, one of construction of the specification and the claims.
88 Moreover, as Lord Hoffman has observed, the need for appellate caution in reversing a judge's evaluation of the facts arises because specific findings of fact, even by the most meticulous judge, "are inherently an incomplete statement of the impression which was made upon [the judge] by the primary evidence"; and the judge's expressed findings "are always surrounded by a penumbra of imprecision as to emphasis, relative weight, minor qualification and nuance", of which "time and language do not permit exact expression, but which may play an important part in the judge's overall evaluation" (Biogen Inc. v Medeva plc (1997) RPC 1 at 45).
89 It is also common ground that the task of the Full Court on an appeal by way of re-hearing (as here) is the correction of error (see the comprehensive review of the authorities by Allsop J in Branir Pty Ltd v Owston Nominees (No. 2) Pty Ltd [2001] FCA 1833 at [22] (Drummond and Mansfield JJ concurring); see also Sydneywide Distributors Pty Ltd v Red Bull Australia Pty Ltd [2002] FCAFC 157 at [50] - [54]).
90 In Branir, Allsop J went on to observe (at [24]) that demonstration of error "may not be straight-forward" where the conclusions can be seen as being made with the advantage of hearing the evidence in its entirety, presented as it unfolded at the hearing with the opportunity over the course of the hearing and adjournments for reflection and mature contemporaneous consideration and assessment, in particular (as here) in a long and complex hearing.
91 Allsop J said (at [25]):
"This is not to elevate ordinary factual findings to the protected position of those based on credit, but it is to make clear, first, the advantages of the trial judge and, secondly, the need for demonstration of error. The inability to identify error may arise in part from the unwillingness of the appeal court to be persuaded that it is in as good a position as the trial judge to deal with the issues, because of the kinds of considerations referred to in [24] above. Or, it may be that the nature of the issue is one such that (though not a discretion) there cannot be said to be truly one correct answer. In such cases the availability of a different view, indeed even perhaps the preference of the appeal court for a different view, may not be alone sufficient: see Zuvela v Cosmarnan Concrete Pty Ltd (1996) 140 ALR 227 at 229-30. In circumstances where, by the nature of the fact or conclusion, only one view is (at least legally) possible (for example, the proper construction of a statute or a clause in a document, where, although, as often said, minds might differ about such matters of construction, there can be but one correct meaning: see generally Corporation of the City of Enfield v Development Assessment Commission (2000) 199 CLR 135, 151-56) the preference of the appeal court for one view would carry with it the conclusion of error. However, other findings and conclusions may be far more easily open to legitimate differences of opinion eg valuation questions, see Fenton Nominees Pty Ltd v Valuer-General (1981) 47 LGRA 71, 73-76."
92 The issue of the proper construction of these patents was considerably refined in the course of argument. As mentioned, there was little controversy about the relevant principles and the real dispute before us rested in their application in the present circumstances.
93 It will be recalled that the trial Judge found, relevantly for present purposes (at [30], [32]), that the essential integers in issue in claim 1 of AP 664820 were these "characterising integers":
(i) the gear case includes fixed end walls at the opposite ends thereof which enclose the sun gears and planetary gears within the housing;
(ii) the sun gear nearest the wheel hub is drivingly connected to that wheel hub by a tubular portion, which passes rotatably through the fixed end wall interposed between the wheel hub and the sun gear nearest the wheel hub; (Emphasis added)
(iii) the transverse axle passes rotatably through the other end wall of the gear case and rotatably through the tubular portion. [Emphasis added]
94 Bartlem, as mentioned, does not contest this characterisation.
95 His Honour, as we have noted, focussed attention on (ii) in rejecting Bartlem's claim of infringement. (Cox, in its notice of contention, as has been seen, further contends that its product also does not include (i) and (iii).) Accordingly, for its part, Bartlem addressed only (ii) in its challenge to the judgment. It will be convenient, in the first instance at least, to consider this challenge on its own.
96 It will be recalled that Bartlem's primary argument is that his Honour misconstrued (ii), above, by reading into claim 1 a requirement that the "tubular portion" be a "discrete and separate" item, when, to the contrary, upon assembly so as to be operational the three components (sun gear, tubular portion and wheel hub) must be connected, indeed drivingly so, in order that the sun gear can drive the wheel hub; and when also the specification provides that the tubular stub axle is formed integrally with the sun gear.
97 Cox seeks to meet Bartlem's argument by submitting (Outline [4]) that the infringement issue was not simply whether the patent, when properly construed, requires the tubular portion to be a discrete and separate item or not. His Honour did not find, as Bartlem's argument suggests, that there was a "tubular portion", which otherwise answered the patent's prescriptions, but that it was not "discrete and separate". Rather, Cox submits, his Honour found (at [72]) that there is simply no tubular portion in its product which could be characterised in the manner claimed in the patent.
98 Cox further submits (Outline [5]) that his Honour has found (at [73]) that in its product, the sun gear is fastened directly to the wheel hub, by bolts which pass through each; so that, Cox argues, its design departs from the patent by dispensing with the need for (1) a member to connect the sun gear to the wheel hub (whether or not of tubular shape); (2) a member to impart drive from the sun gear to the wheel hub; and (3) a member to pass through the fixed end wall of the gear case housing in the course of connecting the sun gear to the wheel hub.
99 In Cox's submission (Outline [6]) Bartlem is, in truth, contending that a conjunction of the rear (collar) of Cox's sun gear with the inside of the wheel hub satisfies the patent's "tubular portion" characteristic, in that, when bolted together (a) they have a tubular shape; and (b) they impart torque from the sun gear to the wheel hub; in other words, according to Cox, Bartlem really asks the Court "to notionally marry up" the back of the sun gear with the inside of the wheel hub in order to find that Cox's product possessed such a portion.
100 Cox then submits (Outline [7]) that Bartlem's argument fails to understand Cox's product, which, according to Cox, is constructed so that the sun gear directly abuts the wheel hub, thereby doing away with the need for any interposed connecting member, of whatever shape, and whether or not "tubular". According to Cox, in its product the sun gear transmits drive to the wheel hub directly, not through any intermediate member; and it was in this connection that Cooper J noted (at [78]) that Cox's product uses only two components to transmit drive (i.e. sun gear and wheel hub), whereas the patent specifies three (i.e. sun gear, wheel hub and tubular portion); so that, Cox submits, its product departs completely from the patent's claims.
101 Cox argues (Outline [8]) that an important foundation for this conclusion was his Honour's findings (at [75]) (based upon his preference for Dr Gilmore's opinion on the point) that the rear or collar of Cox's sun gear is "an integral part" of the sun gear and is "functionally necessary" for its performance as a sun gear. It is, Cox submits, implicit in his Honour's reasons (at [77]) that he likewise accepted that the inside of the wheel hub forms an integral part of the wheel hub, and is necessary for the proper function of the wheel hub. Since Bartlem does not challenge these findings, Cox says, it should be taken, for present purposes, that in Cox's drive mechanism there is a sun gear and a wheel hub; and that there is not interposed any connecting member, whether tubular in shape or otherwise.
102 Cox seeks (Outline [9]) to characterise Bartlem's argument as "artificial", as inviting the Court to create a "tubular portion" out of an undivided part of the sun gear and an undivided part of the wheel hub. According to Cox, Bartlem's argument attempts to attribute a function to each undivided part which, as his Honour held, it does not in truth perform; and, as Cooper J observed (at [77]), the "tubular" shape may be discerned only by an "arbitrary" choice of points on the sun gear and the wheel hub.
103 Cox points out (Outline [10]) that it was only in the context of addressing Bartlem's argument (that a "tubular portion" does exist in the undivided parts of the sun gear and of the wheel hub) that his Honour observed (at [77]) that the wording of claim 1 requires, as a separate item, a tubular portion, characterised in terms of the claim. Cox submits that this conclusion was correct: the words of claim 1 speak of a sun gear, a wheel hub, and a tubular portion in a way that informs the reader that each is to have its own place, and its own function, in the drive mechanism. Contrary to Bartlem's argument, his Honour's reasoning does not merely address the question whether the tubular portion must be "physically separated" from the other components. In truth, the primary Judge was addressing the more fundamental question whether Cox's product incorporates a tubular portion (having the characteristics described in the patent) at all.
104 From his Honour's findings - (1) that the back or collar of the sun gear is an integral part of the sun gear, and functions as part of the sun gear; and (2) that the inside face of the wheel hub is an integral part of the wheel hub - it must follow, Cox says, that in (this part of) Cox's drive mechanism, there is only a sun gear and a wheel hub. Yet the patent requires that there also be an interconnecting tubular portion (Outline [10]).
105 So far as concerns the "tubular stub axle" (AP 698806) the position, Cox submits, is relevantly the same, in principle, as for the "tubular portion" in the other patents.
106 With respect to Bartlem's alternative arguments, Cox contends that they fail for the same reasons as Bartlem's primary argument. These are combination patents, so that to establish infringement, each of the essential features, or integers, must be taken and the departure from an essential integer which his Honour found, namely, the absence of a "tubular portion" having the characteristics described in AP 664820 and AP 692882, cannot, Cox says, be described as an "immaterial" or "trifling" departure within the meaning of the "purposive" rule of patent construction.
107 In reply, Bartlem argues that Cox (Outline [4], above) has misinterpreted his Honour's conclusions at [72] and [76] of his Reasons.
108 It will be convenient to set out here [71], [72] and [76] of those Reasons as follows:
"[71] The substantial idea disclosed by claim 1 is the use of a tubular portion rotating around a transverse axle as the means by which drive is transmitted from the sun gears, enclosed within the gear case housing, to the wheel hub closest to the sun gears. This wheel hub itself rotates around the transverse axle. The means by which this is achieved is characterised by a tubular portion, which passes [rotatably] through the fixed end wall of the gear case interposed between the sun gear nearest the wheel hub and the wheel hub itself. The tubular portion is drivingly connected to the sun gear within the gear case housing; the sun gear is enclosed within the housing by the body of it, which extends co-axially along the transverse axle, and, the two fixed end walls. The tubular portion is drivingly connected to the wheel hub externally of the fixed end wall interposed between the wheel hub and the sun gear.
[72] The drive assembly and gear case used on the Cox "Stockman" range of ride-on motor mowers does not infringe claim 1 of AP 664820 because it does not include a tubular portion which can be characterised in the manner claimed in claim 1 of AP 664820.
…
[76] The applicant submits that when the Cox gear box and drive is assembled the wheel hub and sun gear constitute one item of equipment wherein four functional parts may be identified by reference to the language of claim 1 of AP 664820. In particular, ignoring the housing for the locking mechanism on the Cox wheel hub, the witnesses called by the applicant contend that the metal section between the inner face of the wheel hub and the back of the teeth of the sun gear is cylindrical in shape and functionally drivingly connects the sun gear to the wheel hub and does so by passing through the fixed end wall of the gear case housing. As the cylindrical metal section of the single component when bolted together is generally tubular in shape, the applicant contends that it falls within the description of a tubular portion of the type characterised in claim 1."
109 Bartlem submits the process of reasoning of his Honour here should be interpreted as follows. At [72], his Honour stated his conclusion on the absence of the tubular portion as an essential integer. His reasons then follow. But, Bartlem says, the primary Judge does not conclude that the composite "cylindrical metal section of the single component when bolted together" (at [76]) was not tubular; he held that it was not the tubular portion claimed.
110 In answer to Cox's Outline [5], Bartlem contends that Cox has departed from the words of the claim by insisting upon a separate "member", notwithstanding that the claim refers to a tubular "portion", and that the body of the specification describes a "tubular stub axle" "formed integrally" with the sun gear.
111 It follows, Bartlem says, that the crux of the issue is whether a tubular portion exists in the Cox device by the combination of "undivided parts" (Cox Outline [9]) of the sun gear, and of the wheel hub, or whether a "discrete and separate item" (Reasons at [77], [81]) or "member" is required (Cox Outline [5]). There is no dispute about how Cox's product works. As Cox's Outline [10] describes it - (1) the back or collar of the sun gear is an integral part of the sun gear and functions as part of the gear; and (2) the inside face of the wheel hub is an integral part of the wheel hub, and functions as part of the hub. However, Bartlem submits, the "back or collar of the sun gear" and the "inside face of the wheel hub" are bolted together to form a tubular composite whole, and, as his Honour held, these parts "functionally perform the same task" as the "tubular portion" integer, in addition to the functions (1) and (2) mentioned immediately above.
112 Putting its reply another way, Bartlem submits that the question is whether the claim requires a separate and discrete "monofunction" item, or whether parts of other items can combine to provide the tubular portion. The claim and the description support, Bartlem says, the latter construction, in the absence of any suggestion that the same element, or parts of it, cannot perform two functions. Rather, Bartlem contends, what Cox seeks, impermissibly to do, is to add an "unexpressed proviso" to the patent, a step which Hely J refused to take in construing the patent in Doric Products Pty Ltd v Lockwood Security Products Pty Ltd [2001] FCA 1877 (at [39], [61]).
113 As has been seen, Bartlem's argument that his Honour erred in this connection is put in several ways. But, upon analysis, we think that Bartlem's argument may fairly be reduced to one proposition: that the primary Judge erred in characterising the patents' "tubular portion" and "tubular stub axle" as "separate and discrete".
114 It is true that those words ("separate" and "discrete") do not appear in the language of the patent. But, in our view, it does not follow that his Honour erred in employing that language in the course of his process of reasoning towards his conclusion that there was no infringement here.
115 In this connection, it is important to recall how this question arose in the course of the proceedings. (It will be convenient to proceed upon the footing, for present purposes that the "tubular stub axle" raises, relevantly, the same questions as the "tubular portion".)
116 In its particulars of infringement, Bartlem alleged that Cox's sun gear nearest the wheel hub has "a tubular outward extension to which the wheel hub is secured by bolts" (emphasis added).
117 In his first report, Mr Chaseling expressed the opinion that "the sun gear and the wheel hub effectively become a single component comprising a gear at its inner end and a wheel-mounting flange at its outer end joined by a 'tubular portion which passes rotatably through the fixed end wall'. This tubular portion is formed partially by the rear portion of the sun gear and partially by the inner end of the wheel hub …" (emphasis added).
118 In his supplementary report, (speaking of the "tubular stub axle") Mr Chaseling opined: "[w]henever a novel design, such as the [Bartlem] differential …, is put into production, the designer must develop suitable nomenclature for the components, and can, within reason, choose names arbitrarily …" (emphasis added).
119 In the course of his cross-examination, Mr Chaseling was asked: "[C]laim 1 … contemplates that the wheel hub and the sun gear are connected by something separate therefrom, namely a tubular portion, that is correct isn't it?" Mr Chaseling answered: "Yes".
120 Dr Gilmore's report proceeded to find, or not to find, in the Cox differential, as the case may be, "features" of the Bartlem patents. He opined:
"I am unable to find a 'tubular portion' interposed between the wheel hub and the sun gear nearest the wheel hub."
121 In the course of his cross-examination, Dr Gilmore was asked: "[W]hat is the function of the tubular portion in the [Bartlem patents] …?" Dr Gilmore answered: "[I]t's a discrete … portion with tubular characteristics … which connects a sun gear which contains a collar or boss or hub, and a wheel hub which also contains a collar. So it's a discrete piece which connects those two components together, and those two components are quite discretely identified in the patents … on the drawings, in particular, by numbers, and in the specification by reference to those numbers" (emphasis added).
122 Thus, in the opinion of the experts, the "tubular portion" feature of the Bartlem patent (being a feature of an integer acknowledged by Bartlem to be essential in character) was seen by one expert (Mr Chaseling) as "separate", and by the other expert (Dr Gilmore) as "discrete".
123 Although opinion evidence of that kind could never be decisive of an infringement issue, this explanation of the dynamics of the trial process not only explains the origins of his Honour's reference (at [77]) to the "tubular portion" as "a discrete and separate item", but also, given the unanimity of the experts, meant that, so far as their opinions on this question were relevant, the evidence was all one way. Clearly, to the extent at least that this Honour accepted this, there was no error in the primary Judge's reasoning.
124 Put differently, given the provision of this platform to underpin his Honour's approach to the construction of these patents' claims, the difficulty confronting Bartlem's argument, in contending that the Judge erred by reading, gratuitously, something into the claims that was not there, becomes apparent. In truth, his Honour was merely picking up the unanimous opinion of the experts in his description of the material features of Bartlem's invention. His Honour did this, plainly, as part of a process, first, of identifying those features, and secondly, of distinguishing them from those of the Cox device. Yet the error is said to lie, not so much in the latter aspect, but in the former, that is, in the construction of the claims. Given that state of the evidence, we can discern no error in the Judge's approach to the construction of the claim.
125 Nor are we persuaded that his Honour erred in his identification of the points of distinction he identified between the relevant features of the Bartlem invention and those of the Cox device. True, it was here that the experts differed. On the one hand, Mr Chaseling, as we have seen, went so far as to suggest that, in the present context, nomenclature could even be applied "arbitrarily". On the other hand, Dr Gilmore could perceive nothing "tubular" in the Cox device, and went on to point out some distinct mechanically operative features in the Bartlem invention not found in the Cox equipment.
126 Given the state of that evidence, we are not persuaded that the primary Judge erred in the reasoning towards the conclusion that, in his opinion, the "tubular" feature of the Bartlem patents was not present in Cox's mower. It was in that particular context, that is, the process of identifying, and comparing, the respective features of the Bartlem patent and the Cox device, that his Honour picked up and used the language (which was basically identical) employed by both experts in their explanations of those features. It is not suggested that either of the experts erred in doing this.
127 Nor, in our view, could it be said that the primary Judge erred in using such a formula in his independent process of reasoning towards the conclusion that, in law, there was no infringement. As has been said, it is not suggested that his Honour misstated or misunderstood the general legal principles in this area. Bartlem's complaint, rather, is that the Judge erred in his interpretation of the claims. But, upon analysis, the error is said to have occurred in areas which were essentially factual (in terms of understanding the features of the invention) and which were matters of impression for a trial Judge. In such areas, cogent reasons must be demonstrated if an appellate court is to reverse findings made in such a context. We are unable to identify any such reasons here.
128 For completeness, we would add that, in our view, Doric, above, was a case involving its own question of interpretation of the claims there in issue. It cannot illuminate the interpretation of the present claims.
129 It follows, in our view, that to this extent, the appeal must fail. That being so, we need not consider Cox's contention that there were other departures.