the proper construction of the claims
12 The claims define the invention, which is the subject of the patent, and outline the ambit of the patentee's monopoly; it is the specification which describes the invention: Electric & Musical Industries Ltd v Lissen Ltd (1939) 56 RPC 23 at 41; Ludlow Jute Co Ltd v Low (1953) 70 RPC 69 at 76; AMP Incorporated v Utilux Pty Ltd (1971) 45 ALJR 123 at 128; Decor Corporation Pty Ltd v Dart Industries Inc (1988) 13 IPR 385 at 400; Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd [2001] HCA 8 at [14]. What is not claimed is disclaimed: Electric & Musical Industries Ltd v Lissen Ltd at 39.
13 There are no special rules for the interpretation of patent claims or specifications. They are to be interpreted in the same way as any other written document upon ordinary principles of interpretation: Welch Perrin & Co Pty Ltd v Worrel (1961) 106 CLR 588 at 610-611; Decor Corporation Pty Ltd v Dart Industries Inc at 391, 400. Thus, any purely verbal or grammatical question that can be answered according to the ordinary rules of construction are to be resolved in that way: Welch Perrin & Co Pty Ltd v Worrel at 611.
14 Although the specification and the claims must be read as a whole, it is not permissible to vary or qualify the plain and unambiguous meaning of a claim by reference to the body of the specification: Electric & Musical Industries Ltd v Lissen Ltd at 39; Welch Perrin & Co v Worrel at 610; Decor Corporation Pty Ltd v Dart Industries Inc at 391, 400, 419; Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd at [15]. However, if an expression in a claim is not clear, then it is permissible to resort to the body of the specification to define or clarify the meaning of the words used in the claim: Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd at [15]; Interlego A.G. v Toltoys Pty Ltd (1973) 130 CLR 461 at 479.
15 The claims and specification are not to be read in the abstract. The words used are to be given the meaning which a normal person, having a knowledge of the art and the manufacture at the relevant time and in light of the then common general knowledge, would give to such words: Sunbeam Corporation v Murphy-Richards (Aust) Pty Ltd (1961) 180 CLR 98 at 102; Rhone-Poulenc Agrochimie SA v UIM Chemical Services Pty Ltd (1986) 12 FCR 477 at 496; Kimberly-Clark Australia Pty Ltd v Arico Trading International Pty Ltd at [24].
16 It is not legitimate, in the absence of an express reference in the claim itself, to import into a claim features of the preferred embodiment. The preferred embodiment cannot properly be used to introduce into the definite words of a claim an additional definition or qualification of the patentee's invention: Re Erickson's Patent (1923) 40 RPC 477 at 491; Rehm Pty Ltd v Websters Security Systems (International) Pty Ltd (1988) 81 ALR 79 at 89; Decor Corporation Pty Ltd v Dart Industries Inc at 397. Nor does the body of the specification, insofar as it describes "the method of performing the invention" delimit an area in which the patentee has a monopoly: AMP Incorporated v Utilux Pty Ltd at 130; Decor Corporation Pty Ltd v Dart Industries Inc at 400; Old Diggers Pty Ltd v Azuko Pty Ltd (2000) AIPC 91-571 at 37,565.
17 Having regard to the construction of the claims pressed by the respondent, the words of Gummow J in Rehm Pty Ltd v Websters Security Systems (International) Pty Ltd repay repetition (at p 95):
"... The circumstance that something is a requirement for the best method of performing an invention does not make it necessarily a requirement for all claims; likewise, the circumstance that material is part of the description of the invention does not mean that it must be included as an integer of each claim. ..."
18 I turn to the specification of AP 664820 to determine what exactly is the invention which it describes and for which a monopoly is claimed: Welch Perrin & Co Pty Ltd v Worrel (1961) 106 CLR 588 at 609.
19 The specification acknowledges that the invention "relates to improvements to ride-on mowers incorporating reversible belt drive mechanisms". It identifies the features ordinarily found in a ride-on motor mower incorporating reversible belt drive mechanisms. These are described as:
"Ride-on mowers often utilize reversible belt driven assemblies which transfer drive in the forward and reverse direction through a step down chain drive to the mower's rear transverse drive axle. The drive is actuated by a rocking type pedal in which heel pressure is used to engage reverse drive and toe pressure is used to engage forward drive. For simplicity, light weight and ease of construction, ride-on mowers mostly utilise a transverse drive axle having respective wheel hubs fixed thereto at opposite ends thereof and intermediate spaced chassis mountings which are normally in the form of flangette bearings supporting the transverse axle for rotation. The transverse axle is directly chain driven to a sprocket mounted rigidly on the axle for rotating the driving wheels in unison.
As the width of such mowers is increased for added stability and better traction through wider wheels, the disadvantages of poor steering control inherent in such drive systems becomes more noticeable. Such disadvantages can be overcome to a large extent by the provision of a differential in the drive train to the rear wheels. Unfortunately the differentials available to date have not suited the simple drive trains which utilise a common driving axle as used in most mowers and additionally the available differentials have not had the ability to be selectively utilised or locked in a convenient manner."
20 The specification refers to the prior art base with respect to provision of differentials and differential locks, and identifies the alleged deficiencies in their use and operation. Relevantly, for the invention claimed in this patent, the specification concludes:
"... Accordingly they are not suited for location outwardly of the chassis supports for coupling to the correspondingly located drive sprocket of the final chain drive.
Furthermore the housings for this type of differential have to be made exceedingly robust if they are to cope with the high loadings applied through such drives without misalignment of the respective drive shafts being induced through the applied loads and leading to premature failure.
The locking mechanisms proposed in the abovementioned patent specifications and conventional differential locking mechanisms are not satisfactory for use with ride-on mowers."
21 The specification deals with a turf aerating machine manufactured by OMC in the United States of America and described as the "OMC Greensaire Mk II" as part of the prior art base. The machine had a chain driven differential supported outwardly of simple axle bearing blocks at opposite sides of the vehicle chassis, which support a continuous exposed transverse axle. The arrangement was described in the specification as "much in the manner as described above in relation to ride-on mowers".
22 The differential housing of the OMC machine is open at one end in order to transmit drive from the rear one of a pair of differentially driven sun gears to the adjacent wheel hub. A resilient peripheral seal is used to close the gap between the adjacent wheel hub and the open end of the differential housing. The purpose of the seal is to retain lubricant in the geared differentials and to keep out water, dust or other particulate material. After stating the perceived deficiencies of the OMC arrangement, the specification concludes:
"While it may be possible to make all the components of such a differentially driven transverse axle sufficiently robust to accommodate these wear factors the resultant assembly would be very heavy and expensive to produce. Such a differential would have a large flywheel effect and would place extreme loads on the rest of the drive train during rapid change from forward to reverse drive."
23 The specification then identifies the advantages, which the invention seeks to achieve over the present art base as disclosed in the specification:
"The present invention aims to provide a ride-on mower including a reversible chain drive to a differentially driven rear drive axle assembly which is operable in harsh operating environments safely, reliable and efficiently and which may also be operated without leaking of lubricant from the differential and consequent damage to the differential and or grassed surfaces onto which lubricant may leak.
In a further aspect this invention aims to provide a ride-on mower including a reversible chain drive to a differentially driven rear drive axle assembly which can be selectively locked and unlocked in a convenient and safe manner remote from the differential assembly and/or chain and belt drive assemblies incorporated in the ride-on mower as well as the cutting blades."
24 The balance of the consistory clause sets out that which appears in claim 1 of the claims defining the invention.
25 In the preferred embodiment there is provided:
"... selectively operable differential locking means operable and disposed externally of the gear case and at the side of said one wheel hub which is remote from the gear case for effecting locking of the gear case assembly for rotation with said transverse axle and with said one wheel hub, whereby the respective wheel hubs are locked for rotation in unison with both said transverse axle and said gear case."
26 Save for the substitution of the word "operable" in the first line quoted for "engageable", this formulation is carried over into claim 2 of the claims.
27 The specification goes on to describe, by reference to the accompanying drawings, a typical embodiment of the invention.
28 When the specification is read as a whole, it appears that the invention consists of a differentially driven rear axle assembly, capable of being selectively locked and unlocked from a convenient location remote from the differential assembly, adapted for use in a typical ride-on mower which utilises a reversible chain drive.
29 The components of the combination claimed in claim 1 are a ride-on mower, including a chain driven reversible rear drive axle assembly of a type wherein:
(i) a differential gear case mounted rotatably on and supported by a transverse axle, which supports wheel hubs at opposite ends and which is supported for rotation by spaced chassis mountings intermediate the wheel hubs and through which spaced chassis mountings the transverse axle is attached to the mower's chassis;
(ii) the gear case is mounted on the transverse axle between one wheel hub and the adjacent chassis mounting and that wheel hub is rotatable about the transverse axle;
(iii) a driven sprocket for the chain drive is attached to the gear case for driving the reversible rear drive axle assembly;
(iv) the gear case includes a housing, which extends co-axially of the transverse axle and which housing carries a pair of opposed planetary gears therein for orbital motion about the transverse axle;
(v) opposed sun gears are supported in axially spaced relationship on the transverse axle adjacent to the wheel hub and are differentially driven by the opposed planetary gears;
(vi) the sun gear nearest the wheel hub is rotatable about the transverse axle and is drivingly connected to the said wheel hub, and the other sun gear and the other wheel hub are locked for rotation with the transverse axle.
30 The decisive characteristics of the combination claimed in claim 1 are:
(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;
(iii) the transverse axle passes rotatably through the other end wall of the gear case and rotatably through the tubular portion.
31 The components of the combination in claim 2 are the same as for claim 1 as characterised with the following additional characteristics:
(i) there is provided a selectively operable differential locking means, operable and disposed externally of the gear case and at the side of the wheel hub which is remote from the gear case; and
(ii) the locking means is for effecting locking of the gear case for rotation with the transverse axle and with the wheel hub, whereby the respective wheel hubs are locked for rotation in unison with both the transverse axle and the gear case.
32 For the purposes of claims 1 and 2 of AP 664820, the essential integers in terms of the issues raised between the parties are the characterising integers (i), (ii) and (iii) in respect of claim 1 with the additional integers (i) and (ii) in respect of claim 2.
33 Claim 1 in AS 692882 is identical with claim 1 in AP 664820, save for the immaterial substitution of the word "mounting" for "support" in line 11 of claim 1 of AP 664820. Claim 1 and claim 6 of AS 692882 are identical save for the description of the gear set carried by the gear case housing. In claim 6 the words are "...which housing carries a differential gear set having opposed differentially driven sun gears supported in axially spaced relationship on the transverse axle". In claim 1 the words "...which housing carries a pair of opposed planetary gears therein for orbital motion about the transverse axle; opposed sun gears are supported in axially spaced relationship on the transverse axle adjacent said one wheel hub and are differentially driven by the opposed planetary gears." Each of claim 1 and claim 6 are characterised by the three essential characteristics which limit the claim made.
34 Claims 7, 8 and 9 of AS 692882 each require as a component of the claimed combination a ride-on motor mower as claimed in claims 1 or 6 together with further characterising elements. These elements all relate to the differential locking means.
35 The claims in AS 698806 relate to specific combinations of integers for differential locking of chain driven reversible rear drive axle assemblies. The need sought to be satisfied by the claimed invention is identified in the specification as follows:
"Many domestic and ride-on mowers have driven rear wheels utilising a simple drive train to transmit power from the motor to the rear wheels. Typically the drive is transmitted by belts or chains to a transverse rear axle which supports the rear wheels. This system is generally satisfactory. However as the width of mowers increase the disadvantages inherent in such drive systems becomes more noticeable. Such disadvantages can be overcome to a large extent by the provision of a differential in the drive train to the rear wheels. The differentials available to date have not suited the simple drive trains which are utilised in most mowers and additionally such differentials have not had the ability to be selectively utilised or locked. Furthermore, the locking mechanisms for such differentials have been difficult and inefficient in use and/or increased the risk of damaging the drive mechanism and/or wheel mountings.
This invention aims to alleviate the abovementioned disadvantages and to provide a chain driven reversible rear drive axle assembly for a ride-on mower which will be reliable and efficient in use."
36 The components which make up the chain driven reversible rear axle assembly for a ride-on mower as claimed are:
(i) a transverse axle supporting respective wheel hubs at opposite ends thereof one hub being freely rotatable about said transverse axle and the other hub being fixed to said transverse axle;
(ii) a differential gear case mounted rotatably on and supported by said transverse axle and forming a housing extending along the transverse axle;
(iii) a driven sprocket for the chain drive attached to the gear case;
(iv) a pair of opposed planetary gears supported by said housing for orbital motion about the transverse axle;
(v) opposed sun gears supported in axially spaced relationship along and co-axially about the transverse axle and within said housing and meshed with said opposed planetary gears for differential rotation thereby;
(vi) a tubular stub axle rotatable about said transverse axle and drivingly connected to said one hub and the sun gear which is nearest said one hub, the other sun gear being locked for rotation with said transverse axle, and
(vii) an externally accessible locking member associated with said one hub and manually moveable to a locking position at which it locks said one hub for rotation with said gear case and said transverse axle.
37 The combination claim is for a substantially new thing, wherein the inventive step lies in the choice and management of the integers and therefore each of the integers claimed is an essential integer: May v Higgins (1916) 21 CLR 119 at 121; Sami S Svendsen Inc v Independent Products Canada Ltd (1968) 119 CLR 156 at 164 - 165; Wellcome Foundation Ltd v VR Laboratories (Aust) Pty Ltd (1981) 148 CLR 262 at 281; Winner v Ammar Holdings Pty Ltd (1993) 41 FCR 205 at 226.
38 Claims 5, 6, 7 and 8 of AS 698806 all include as an integer a chain driven reversible rear drive axle assembly as claimed in claim 1, with additional specific integers relating to the locking means (claims 5 and 8) or the gear case and housing (claims 6 and 7).
39 AP 723748 like AS 698806 is a claim for a combination, wherein it is claimed that the inventive step lies in the choice and management of the integers comprised in the rear axle assembly for a ride-on mower as claimed in claim 1, with a locking means as claimed in claim 2.
40 The essential integers of claim 1 of AP 723748 are:
(i) a transverse axle;
(ii) a fixed wheel mount at one end of the transverse axle;
(iii) a further wheel mount supported rotatably about the opposite end of the transverse axle;
(iv) a sun gear fixed on the transverse axle adjacent the further wheel mount;
(v) a gear case assembly having planetary gears therein which engage with said fixed sun gear;
(vi) a mounting means for mounting the gear case rotatably about the transverse axle;
(vii) a chain drive for rotating the gear case about the transverse axle;
(viii) a further sun gear rotatable about said transverse axle and meshed with said planetary gears to form a differential drive;
(ix) a connector means for connecting the further wheel mount to the further sun gear; and
(x) a selectively operable locking means for locking the transverse axle to the further wheel mount.
41 The additional integers required by claim 2 are:
(i) the locking means includes a manually operable lock member supported on the further wheel hub;
(ii) which is accessible at the outside thereof.
42 I turn to claim 1 of AP 664820. The only area of controversy as to the proper construction of the claim lies in the clauses which characterise the combination claimed. The respondents submit that there are ambiguities of meaning in the words and phrases "fixed end walls", "enclose" and "within" in the first characterising paragraph; by the phrases "tubular portion" and "passes rotatably through the fixed end wall" in the second characterising paragraph; and finally "drivingly connected ... by a tubular portion which passes rotatably through the fixed end wall".
43 The respondents rely upon the evidence of Dr Duncan Gilmore, a mechanical engineer, to submit that there is ambiguity sufficient to entitle limitations which appear in the drawings forming part of the body of the specification and in the preferred embodiment to be imported into the language of the claim. The applicant submits that such a course is impermissible and that the meaning of the words is clear in the context and that no words of limitation should be imported.
44 Dr Gilmore expressed the opinion that the word "fixed" can have either of two meanings, being fixed as in stationary, or fixed as in fixed and able to be detached. Dr Gilmore favours the second meaning because the preferred embodiment shows end walls fixed in place by bolts which enables the end walls to be detached by releasing the bolts holding them in place.
45 In my view, there is no ambiguity present in the wording of claims 1 and 2 of AP 664820, which permits or requires features that appear in the preferred embodiment to be incorporated into the language of the claims.
46 The integers of the combination for present purposes commence with a differential gear case mounted rotatably on and supported by a transverse axle. The gear case "... includes a housing which extends co-axially of the transverse axle and which housing carries a pair of opposed planetary gears therein for orbital motion about the transverse axle". The planetary gears are within the housing and by some means supported within the housing; the housing co-axially rotates around the transverse axle with the orbital motion of the planetary gears. The planetary gears differentially drive opposed sun gears which are supported in axially spaced relationship on the transverse axle adjacent to one wheel hub. Because the gear case housing extends co-axially of the transverse axle, the housing will of necessity have two opposed ends through which the transverse axle passes. The claim specifically provides for the integers present at each end of the housing by way of "fixed end walls".
47 The phrase "the gear case includes fixed end walls" means in this context that the fixed end walls are added and form part of the gear case at the opposite ends of the housing. So much flows from the use of the word "includes" in its ordinary meaning in this context, namely "to add as part of something else": Collins English Dictionary; Australian Edition (1979) at p 740. So understood, "fixed" means fixed as part of the gear case. Save for the transverse axle and a tubular portion, which pass rotatably through the end walls, as provided in the language of the claim, the end walls are to perform the function of enclosing the sun and planetary gears within the housing. That is, the end walls are used to enclose all the gears within the housing of the gear case.
48 The words "enclose" and "within" bear their ordinary meaning in the claim. That is, the end walls which are fixed to the housing close off the ends of the housing to contain or hold the gears within the housing. The word "within" means "in; inside; enclosed or enclosed by": Collins English Dictionary at 1165.
49 The words of the claim mean that the gears are wholly encased by the housing and the fixed end walls at the opposite ends of the housing. Such a construction is confirmed by reference to the body of the specification wherein the claimed invention is distinguished from the OMC turf aerator.
50 The feature identified in the OMC turf aerator which is regarded as a disadvantage, and which the claimed invention seeks to overcome, is the use of a resilient peripheral seal to close the peripheral gap between the adjacent wheel hub and the open end of the differential housing. The use of such a seal to prevent lubrication loss or the entry of water, dust and other particulate material, is claimed to be ineffective and liable to fail wholly or partially, over time. The invention in suit seeks to overcome such problems by the provision of a fixed end wall to the otherwise open end of the differential housing.
51 The claim is silent as to how the end wall is to be fixed to the casing. Dr Gilmore introduces the requirement that the end walls be attachable and detachable because the drawings in the body of the specification show the end walls in the preferred embodiment being held in position by four bolts passing through the end walls and clamping the end walls to the housing when tightened. To import such a limitation into the claim is neither necessary nor permissible for the reasons I have outlined earlier.
52 The sun gear nearest to the wheel hub is drivingly connected to that hub "by a tubular portion which passes rotatably through the fixed end wall interposed between" the wheel hub and the sun gear.
53 Mr Arthur William Chaseling, an engineer, gave evidence on behalf of the applicant. He expressed the opinion that in engineering terms and in ordinary speech "tubular" meant "of or pertaining to a tube", and that tube meant "a hollow usually cylindrical body of metal, glass or rubber, or other material used for conveying or containing fluids and for other purposes". In this regard, he adopted the primary definition contained in The Macquarie Dictionary 3rd Ed (1977) at 2271. In his view the only essential features were that there should be a body which was hollow and that there was no requirement of a length to diameter ration.
54 Dr Gilmore on the other hand expressed the opinion that, in engineering terminology "tubular" required that the object have an elongated shape, where the elongation has a ratio of length, the inner diameter of which greatly exceeds unity. The distinction which Dr Gilmore draws is between a ring or washer, which is hollow and cylindrical in shape, and a tube. A ring or washer would never in engineering terminology be regarded as meaning a tubular section.
55 The dictionary definitions in the Collins Dictionary and Oxford Short Dictionary support the position taken by Dr Gilmore. The Collins Dictionary defines a tube as "a long hollow and typically cylindrical object used for the passage of fluids or as a container". The Oxford Short Dictionary defines the primary measuring of a tube as "a hollow body, usu. Cylindrical, and long in proportion to its diameter, of wood metal glass etc used to convey or contain a liquid, or for other purposes; a pipe 1658". The Oxford also defines "tubular" as "tube shaped; constituting or consisting of a tube; cylindrical, hollow and open at one or both ends."
56 In my view, in the context of claim 1, "tubular" has the meaning to be found in the Collins and Oxford Dictionaries, as explained by Dr Gilmore in its application in engineering terminology. The extent of the elongation necessary is always a question of judgment and degree. However, there must be, in my view, more than the existence of a hollow in an object before that object can be described as being a "tubular portion" within the meaning of claim 1.
57 The other area of contention between the applicants and the respondents' witnesses relates to the meaning to be given to the term "tubular stub axle" in claim 1 of AS 698806. Dr Gilmore expressed the opinion that a "tubular stub axle" would be interpreted by a person skilled in the art as a short hollow axle which occupies the centre line of rotation. He continued:
"To a reader of the specification, the term 'stub axle' has a particular meaning in my opinion ie. a stationary but relatively short axle which might have a length to diameter ratio between approximately 1.0 and 5.0."
58 Dr Gilmore was cross-examined on this part of his report and gave the following evidence:
"I think in, as it were, general engineering, you're saying, is this right, in the first paragraph, no, a tubular stub axle is a short hollow axle which occupies the centre line of rotation and this doesn't do that because the transverse axle does that?---That's correct.
But in our area of discourse here, where we have a transverse axle and we're told in the specification that the tubular stub axle or tubular portion is outside that and bearing on it, I think you go into the next paragraph to say, well, we have a different area of discourse here where we're not occupying the centre. Have I got that right?---Yes, it's not - it doesn't occupy the centre line, therefore the terminology is probably inappropriate.
But doing the best we can to give the patent a sensible meaning, I think is what you've done, with respect, in that paragraph. You say:
To a reader of the specification the term, stub axle, has a particular meaning, namely -
is that right -
namely, one that does not -
so far -
does not occupy the centre of rotation?---Well, I come back to the fact that and I suggest an alternative description there. I think that it should be called a tubular sleeve really rather than tubular stub axle. Tubular stub axle does give the wrong impression.
But given the fact that I'm stuck with a tubular stub axle in one of the cases?---Well, I can't help that.
But you say there - you did try there to help it and you gave it a particular meaning, ie:
... a stationary but relatively short axle which might have length to the diameter ratio between approximately one and five -
Now the tubular part, that you and I have been describing where bolted together, is that, isn't it?---Well, that's to the reader of the specification because the specification includes drawings.
Yes?---And the drawings do show you which - forgetting the English, the meaning of the English language - the drawings and the specification do show you what the person who drew up the patent was meaning when they referred to a tubular stub axle. They say, well, this part is a tubular stub axle; forget what - forget what else it might mean, this is what I define as a tubular stub axle. And if you read the specification and the drawings they will point you to what the patents refer to as a tubular stub axle.
And, in that case, the portion that we're talking about is a tubular stub axle - part, sorry - joined up together part - is a tubular stub axle?---As shown in the specifications and drawings and as we discussed between - yes, between gears and flange, not - yes. Including the hobs and collars and - - -
Binding it all together?---Well, yes, throwing away the meaning of some of the other collars and hubs that are elsewhere described; dismissing those and lumping them all together, then you would come to that conclusion.
...
I just wanted to show you Exhibit 3. I think that's the one that talks about the tubular stub axle on page 9. Take your time to read it but this is what I want you to think about. I just want to suggest that it's clear on the face of claim 1, without resort to the specification, that the tubular stub axle does not occupy the centre line of rotation?---Yes, I agree with you there. It does say 'a tubular stub axle rotatable about said transverse axle.'
So the particular meaning that you give in your section on page 15 can be discerned without resort to the body of the specification?---Well, it can be, with difficulty though I must say, because it is - it does throw up confusion in the reader's mind, I believe, because it's not what you would expect to be a - reading that you wouldn't expect that sort of component to be described as a stub axle in my opinion.
But we discard the centre line of rotation by reading the claim, don't we? Sorry, let me start again?---Well, that's the - I think that is the confusion that's thrown up, I guess, in the reader's mind.
But a mechanic or an engineer interprets it in a - just asked in a pub what's a tubular stub axle, would say a short, hollow axle which occupies the centre line of rotation - I'm looking at your page 15?---Yes.
If the mechanic is then handed claim 9 and told that rather than occupying the centre line of rotation it is rotatable about an axle, a transverse axle, they'll keep the short, hollow axle part of their definition in their mind and abandon the centre line of rotation part of it?---Yes, but what you said there was that the mechanic was told that the tubular stub axle - I think you said the words were rather than occupy the centre line of rotation, it rotates about a transverse axle. Unfortunately, the claims don't tell you that. They just tell you one part of it and so you're left without that preface. So where do you go for the preface? Perhaps you go back to the specifications and drawings for the preface.
But if you're looking at line 19, you've got no doubt that the tubular stub axle which we know is short and hollow - do we know that so far? I bring that with me, don't I, as a mechanic or an engineer, that it's short and hollow?---As I say in the report, short and perhaps length to diameter ration is between 1 and 5, yes.
I carry that with me, and I know from reading line 19 and line 20 that it is rotatable about the axle - the transverse axle, which I've already just read - and drivingly connects the hub and the sun gear?---So what's the question, sorry?
Well, do you agree with what I just said: a skilled mechanic, or an engineer who carries with them the notion of a stub axle as being short and hollow, and occupies the centre of rotation, then reads claim 9 and sees that this tubular stub axle is rotatable about a transverse axle that goes from - all the way from hub to hub and is drivingly connected to one of the hubs and the sun gear, they will be able to get a stationery, using your words, but relatively short axle which might have a length to diameter ratio between approximately 1 and 5, that sits on the outside of the transverse axle?---That would be one interpretation, but I just suggest that they may come up with others and they may look further for - just to confirm their - the opinion which is gained from a short number of words."
59 Mr Chaseling, in his report, expressed the following opinion:
"4.3 Claim 1 of this patent also includes the feature:-
'A tubular stub axle'
4.4 In engineering circles, the term 'axle' is used for two types of component. It can be used to describe the structural component to which a wheel is attached for rotation thereabout, or as a torsion member which applies torque to a wheel. The use of the term 'axle' for both of these applications is shown in Appendix A, taken from the spare-parts book for a Caterpillar 769 truck. In the front wheel sub-assembly, the term 'axle' is applied to a structural member on to which the wheel is mounted through bearings and about which it rotates. In the rear-drive assembly, the term 'axle' is applied to a drive shaft which does not support the wheel, but which supplies drive torque to it. The term 'stub' is merely added where a component is relatively short compared with its other dimensions, and is used in connection with other elements such as gear teeth and screw threads.
4.5 Thus the application of the terms 'axle' or 'stub axle' to a 'tubular portion' which carries drive torque to a wheel is within normal engineering usage. In my opinion, the term is an appropriate one in terms of function, and it is irrelevant to the terminology whether this component contains internal bushings or the like to accommodate yet another shaft."
60 Under cross-examination, Mr Chaseling gave the following evidence as to the meaning and use of the phrase "tubular stub axle":
"A tubular portion is a wider description than a tubular stub axle. That is correct, isn't it?---Yes.
In other words a tubular stub axle would be sub-set of what otherwise could be regarded as a tubular portion?---Yes.
And both a tubular portion and a tubular stub axle are each narrower definitions or terms than the term 'connector means'?---Yes.
Could I take you to patent 698806, exhibit 3? If I could take you to page 9, line 19? Do you recall that in the petty patent the claim 1 refers to the wheel hub and the sun gear being connected by a tubular portion?---Yes.
The word 'by' is used. If you look at page 9 of this patent, line 19:
A tubular stub axle rotatable about said transverse axle and drivingly connected to said one hub and the sun gear which is nearest the said one hub.
Which is a different form of language than in the petty patent because it's talking about connecting something to something rather than connecting by?---Yes.
The use of the word 'to' would make it even clearer, wouldn't it, that what is being connected are in effect three things, a tubular stub axle, a hub and a sun gear?---Yes.
...
The term, tubular stub axle, to a mechanic reading a patent which includes that term, it would be read as meaning a short tubular axle which bears the wheel or the wheel hub wouldn't it?---Not necessarily. An axle is often described as a component which provides torque drive rather than supports a wheel.
...
But when you add the word 'tubular' to stub axle and you have a tubular stub axle in the context of this patent, it's clearly referring to a sleeve isn't it that fits over an axle and being a sleeve that bears the wheel hub?---No, not necessarily. There is nothing in the concept to say that - say in that particular axle that there couldn't be a hole down the middle of it. In fact, there is a hole part-way down it, but there is nothing in the well to stop that from being a tubular axle which drives, but doesn't support a wheel.
Could I take you to paragraph 6.6 of your first report where you talk about tubular stub axle and you say:
This feature was most important to the invention as it allows the adjacent wheel hub to be supported on an axle which passes through the centre of the tubular portion.
?---Yes.
And the way in which you have read the specification and that description as to what is important about the tubular stub axle would be the way I assume that you would regard anyone else skilled in the art would read it?---Yes.
So it has the effect of allowing the rear axle to be supported on two bearings?---Yes.
And it allows the - more accurately the wheel hub to be supported on two bearings; it's supported by the axle and by the tubular stub axle; that's correct isn't it?---No. Well, the tubular stub axle is intended as a driving component and the support for the wheel hub comes from the axle."
61 The axle of which Mr Chaseling is speaking in this last answer is the transverse axle, which passes through the tubular stub axle and which is rotatable around the transverse axle.
62 The meaning to be given to the term tubular stub axle in claim 1 of AS 698806 is to be ascertained firstly from the context in which it is used in the claim. The tubular stub axle described in the claim is but one of a number of components making up the claimed combination of a "chain driven reversible rear drive axle assembly for a ride-on mower".
63 The first component claimed is "a transverse axle supporting respective wheel hubs at opposite ends thereof one hub being freely rotatable about the said transverse axle, and the other being fixed to the said transverse axle". What is taught is that the wheel hubs are supported at opposite ends of the axle by the axle and that one hub is supported in such a way to allow it to be freely rotatable about the transverse axle. Next there is a differential gear case mounted rotatably on and supported by the transverse axle. One of the features of the gear case is that it contains opposed sun gears supported in axially spaced relationship along and co-axially about the transverse axle.
64 The tubular stub axle specified in claim 1 has two defining features. Firstly, it is rotatable around the transverse axle. Secondly, it is drivingly connected to one wheel hub and the sun gear in the differential gear, which is nearest that wheel hub. The requirement that the other sun gear is locked for rotation with the transverse axle, indicates that the tubular stub axle is drivingly connected to the wheel hub, which is rotatable around the transverse axle. In the context of the claim, it is not an essential characteristic of the tubular stub axle that it support the wheel hub, as this is provided by the transverse axle, or that it occupy the centre line of rotation, as it is clear that the stub axle as claimed is rotated around the transverse axle. Upon analysis, I am not persuaded that there is any real difference between the understanding of Dr Gilmore and Mr Chaseling as to what is for the purposes of the patent a tubular stub axle, and what function it performs. As Dr Gilmore says in his report:
"... As defined by Bartlem Pty Ltd, the 'tubular stub axle' provides a sleeve which transfers mechanical power from the differential to the wheel. If the 'tubular stub axle' was absent, the ride-on mower could not be driven or moved under its own power."
65 My observations made earlier in these reasons to the meaning of "tubular portion" in respect of claim 1 of AP 664820 are also relevant to so much of the tubular stub axle as is constituted by a tubular portion of it.