(a) The absence of references in the specification to the anchor member moving
19 The Appellant accepts that the anchor member depicted in Figures 2 and 3 does not move by more than a de minimis amount when struck by the falling drill rod section. However, it submits that this is not so in the case of the invention depicted in Figure 4. All of the references relied upon by the trial judge to conclude that the anchor member could not move by more than a de minimis amount were concerned with the invention depicted in Figures 2 and 3 and, so the argument went, her Honour had failed to attend to the fact that the anchor member in the invention in Figure 4 could, in fact, travel down the bore hole. That fact was said to teach powerfully that the anchor member could move by more than a de minimis amount.
20 To grasp the Appellant's point about this it is necessary to detour through the differences between the embodiment depicted in Figures 2 and 3 and the embodiment depicted in Figure 4. The first embodiment is depicted in two different positions, one with the anchor member located outside the bore but with the impact reduction member within the bore (Figure 2) and the other with the anchor member fully inserted into the bore hole (Figure 3). The second embodiment is depicted only with the impact reduction member fully inserted into the bore hole and the anchor member outside the bore (Figure 4). The notational references for all three figures are largely the same. Figures 2, 3 and 4 are as follows:
21 For present purposes it is to be noted that the detailed description of the embodiments in the specification explains that:
(a) the impact reduction member is numbered '5';
(b) the anchor member is numbered '2';
(c) the anchor member consists of a 'split' tube formed from a round steel tube or pipe which is numbered '3';
(d) the split in the tube is a gap which extends longitudinally along the tube and is only illustrated at 'G' in Figure 3;
(e) the diameter of the split tube ('Do') is larger than the diameter of the bore hole ('Di');
(f) however, the diameter of the split tube at the front end of the anchor member ('Dr') is smaller than that of the bore hole ('Di') which permits it to be inserted into the bore hole;
(g) when the part of the split tube which is wider than the diameter of the bore hole reaches the bore hole it is able to contract as it is forced in (because of the presence of the gap or slit at 'G'), thus enabling it to maintain a friction fit inside the bore;
(h) the difference between Figures 2 and 3 demonstrates how the predominantly wider split tube is forced into place in the narrower bore hole; and
(i) in each figure the impact reduction member has a taper of α° although it will be seen that the nature of what is tapered is quite different as between the two embodiments.
22 In the case of the embodiment in Figures 2 and 3, the central idea is that when the falling drill rod section hits the impact reduction member (in both figures travelling from the right) it drives the impact reduction member into the anchor member. The deeper into the anchor member the tapered impact reduction member travels the greater its girth becomes and the more outward pressure it exerts on the steel tube of the anchor member. This, at first, retards and, then, ultimately stops the movement of the impact reduction member.
23 It is not in dispute that on and shortly after impact, the anchor member in the embodiments depicted in Figures 2 and 3 would move by no more than a few millimetres. In these embodiments, there is significant movement of the impact reduction member relative to the anchor member so as to achieve a 'gradual or extended transfer of impact loading' to the anchor member: 556 Patent at p 10 line 27 to p 11 line 12.
24 By contrast, the embodiment in Figure 4 works in a different way. In this embodiment, it will be seen that the impact reduction member is different to the impact reduction member in the embodiment in Figures 2 and 3. Whilst both impact reduction members may be said to be tapered, their retardant action differs. In Figure 4, the retardant action of the tapered impact reduction member derives from its interaction with the falling drill rod section which is forced into contact with the bore wall the further down the tapered impact reduction member it travels. In this embodiment, the anchor and impact reduction members do not move relative to each other. In the embodiment in Figures 2 and 3, by contrast, the retardant action of the impact reduction member derives from its movement relative to, and consequent interaction with, the anchor member.
25 The debate between the parties about the Figure 4 embodiment is whether the anchor member in Claim 1 provides braking action by itself travelling down the bore hole. A proposition which sounds as though it answers this question but which does not is that the anchor member, in the event that it did travel down the bore, would provide braking action in the course of doing so. The debate between the parties concerns how the anchor member in Claim 1, properly construed, in fact operates. This deceptively similar proposition is, by contrast, a theoretical statement about what would happen if the anchor member in Claim 1 did in fact travel down the bore hole. It takes as its point of departure an assumption that the anchor member in Claim 1 does, in fact, travel down the bore and, hence, assumes the answer to the question under consideration. Here the important point is that proof that an anchor member driven down a bore hole provides braking action through frictional force is not proof that this is, in fact, what the anchor member in Claim 1, properly construed, is intended to do. A sofa tied to the back of a car will operate to retard its forward progress but this tells one nothing about the sofa's intended purpose.
26 There was evidence of this theoretical kind that an anchor member, if driven down the bore hole, would provide frictional braking force. At trial the Appellant called Mr Davison, an expert in mining engineering, and he gave evidence to this effect at [109] of his affidavit ('…it remains the case that any movement of the safety system will have the effect of absorbing the kinetic energy from the falling drill rod'). The Respondents called Dr Fuller, a geotechnical engineer who is also an expert in mining engineering. He accepted that if the anchor member in Claim 1 was not required to keep the Safety System in place when struck by a falling drill rod section, the effect of its movement down the bore hole would be to brake the motion of the falling drill rod section (I discuss this evidence in more detail below). However, neither Mr Davison's nor Dr Fuller's evidence to this effect is evidence that the anchor member in Claim 1 is intended to retard the motion of the falling drill bit by travelling down the bore hole.
27 On the actual question between the parties of whether the anchor member in Claim 1 could, when struck by the falling drill rod section, travel down the bore hole and thereby provide braking action, there was also evidence. The Appellant submits that this evidence showed that the anchor member in Claim 1 could travel down the bore hole once struck by a falling drill rod section and thereby contribute to slowing the falling drill bit by the generation of frictional force between the anchor member and the bore wall. For the following reasons, I do not accept that the evidence established this proposition. It comprised two different portions of testimonial evidence.
28 The first portion consisted of evidence from Mr Davison at [42] of his affidavit that the anchor member performed 'the role of locating and holding the safety system in position in the bore until such time as it may be struck by a falling drill rod section'. If accepted, this evidence left open the possibility that after the Safety System was struck by a falling drill rod section the anchor member ceased to hold the Safety System in place. If read that way, one might extract from it that from that point on (i.e. during the impact event) the anchor member might travel down the bore hole and thereby generate frictional force. It is not entirely clear to me that Mr Davison really did go so far as to say this but, in any event, it is not necessary to determine whether he did so because Mr Davison himself abandoned any such contention.
29 This he did in the Joint Expert Report at p 2 where he indicated for the purposes of clarity that he did not mean in [42] of his affidavit that the holding function of the anchor member was performed 'only until such time as it may be struck by a falling drill rod section'; that is to say, the holding function of the anchor member continued after the Safety System was struck by the falling drill rod section. As such, Mr Davison's evidence did not establish that the anchor member in Claim 1 slowed the falling drill rod section by travelling down the bore and generating frictional force.
30 The second portion of testimonial evidence relied upon by the Appellant came from Dr Fuller. Dr Fuller's evidence was that the anchor member in Claim 1 did not travel down the bore hole. In his third affidavit at [8], Dr Fuller said, in response to Mr Davison's statement at [42] to which I have just referred, that 'To the contrary, the specifications of each of the Patents disclose to me that the purpose of the anchor member is to hold the safety system in place both before and during the impact from a falling drill rod section.'
31 However, Dr Fuller was cross-examined about this and the Appellant submits that in his cross-examination he conceded the anchor member in Claim 1 could retard the motion of the falling drill rod section by moving down the bore hole during the impact event.
32 The cross-examination took this course: first, the cross-examiner, Mr Smith, endeavoured to have Dr Fuller agree that a feasible mode of operation for the Figure 4 embodiment was one which involved the anchor member in a degree of 'downhole movement' which Dr Fuller rejected ('No, I don't agree'): T214.24-214.28.
33 Secondly, Mr Smith then embarked on a series of questions about the alleged infringing product, the SafetySpear. Here it is useful to know that the SafetySpear has three plastic rings which do indeed retard the movement of the falling drill bit by travelling down the bore. The nub of the debate between counsel and Dr Fuller concerned Mr Smith's suggestion that since the SafetySpear had the same purpose as the Figure 4 embodiment it was logical that the anchor member in Figure 4 could also travel down the bore. Cutting out some unnecessary detail, Dr Fuller declined to go down this path with Mr Smith on the basis that it wrongly assumed that the three rings in the SafetySpear were anchor members within the meaning of Claim 1 which, in his view, they could not be since they moved when the anchor member in Claim 1 could not: T215.10-215.23.
34 Thirdly, Mr Smith then suggested that Dr Fuller was basing his understanding of the Figure 4 embodiment on his interpretation of the word 'anchor', a proposition with which Dr Fuller agreed at T215.31.
35 Fourthly, Mr Smith then sought to elicit what Dr Fuller's understanding of the Figure 4 embodiment would be if the word 'anchor' were omitted from the 556 Patent. This elicited an objection from Mr Cordiner who appeared for the Respondents at trial. The debate occupies a page or so of the transcript. The primary judge expressed the view that Mr Smith's question did not appear to be particularly relevant but permitted it anyway: T217.11-217.12. The question was then asked again. There was a further objection which, after some back and forth, was withdrawn and the final form of the question was put at T218.22-218.26 in these terms:
MR SMITH: And what I'm suggesting to you is, putting the word "anchor" to one side and just considering how that might work in practice, that a sensible mode of operation for [the Figure 4 embodiment] is that it might resist that falling drill rod by slowing it down to a stop, including by the lower section moving down through the bore with frictional resistance.
36 Before committing himself to answering this question Dr Fuller indicated a desire to know where the anchor member was located in the bore; in particular, whether it was flush with the rock face or whether it was further up the bore hole. His concern was that if it was installed at the rock face then any downward movement would reduce its 'capacity' (T218.33-218.35) by which it may be assumed he meant that the anchor member would, to some extent, no longer be in the bore and hence would have reduced frictional resistance (or, one imagines, if it went far enough, none apart from that afforded by the air through which it would then be falling). Mr Smith adjusted his question to overcome this point by inviting Dr Fuller to assume that the anchor member was located two metres within the bore.
37 Dr Fuller then accepted that in this case the anchor member would act to slow down the falling drill rod section. Dr Fuller's full answer was at T219.5-219.6 and included a caveat:
DR FULLER: Yes, it would slow it down. But whether it would slow it down sufficiently to stop it, I don't know.
38 Thus Mr Smith was successful in winning from Dr Fuller the concession that if the patent did not contain the word 'anchor' and if the not-the-anchor member were inserted two metres into the bore, it was possible that the not-the-anchor member would slow down the falling drill rod section by travelling down the bore although whether it would slow the drill rod section sufficiently so as to stop it was not known. As I have observed above, this evidence demonstrated that if the anchor member did travel down the bore after it had been struck it would generate frictional force with the bore wall and retard the downward motion of the descending drill rod section. But, as I have also indicated above, that was not the question to which the case gave rise which was instead whether the anchor member in Claim 1 was intended to travel down the bore hole or remain fixed in place.
39 Thus, I do not accept that there was any evidence from Mr Davison or Dr Fuller on that question. Necessarily, I reject the Appellant's allied contention that the trial judge had overlooked this non-existent evidence. The primary judge referred to this debate, such as it was, at J [113]-[114]:
113 Second, Jusand criticised Dr Fuller's reasoning which it said was based on the particular embodiment shown in Figure 2. According to Jusand, Dr Fuller read down the disclosure in the Patents to fit with his assumed meaning of the word "anchor". Jusand submitted that Dr Fuller read the Patents with an assumption that the patentee intended to exclude from the scope of its monopoly embodiments that Dr Fuller recognised in cross-examination would feasibly work so as to achieve the object of the Patents.
114 In cross-examination Dr Fuller agreed that down-hole movement of an anchor member would absorb energy. When Dr Fuller was asked to consider the embodiment shown in Figure 4, he understood that it did not rely on the same principle shown in the Figure 2 embodiment, and that it relied solely on its frictional engagement with the bore walls. It would therefore have a more constant capacity to resist downward movement.
40 It is true her Honour did not refer to the detail of the cross-examination set out above but the reasons show that her Honour was perfectly aware that the Appellant was putting a case on the Figure 4 embodiment. Whilst it is true that her Honour did not refer to the concession that Mr Smith had won from Dr Fuller this is because that concession did not relate to what the anchor member in Claim 1 meant but to the theoretical (and, as the Respondents correctly submitted, irrelevant) question of whether an anchor member driven down a bore hole generates frictional force with the bore wall and hence retards the falling drill rod section.
41 Another way of seeing why this is so is to observe that what Dr Fuller accepted, with a caveat, was that if the word 'anchor' did not appear in Claim 1 then he would accept that the anchor member in Figure 4 could operate to break the falling drill rod section by travelling down the bore hole. For this evidence to be of any use, it was necessary for the hypothesis on which the evidence rested to be made good. That hypothesis was that Claim 1 did not use the word 'anchor'. That hypothesis could never have been made good. Whilst I well understand on pragmatic grounds why the primary judge permitted this line of questioning to proceed, there was never any possibility that it was relevant since there was never any possibility that Claim 1 did not have the word 'anchor' in it. Her Honour's presentment that this evidence was probably not relevant at T217.11 was therefore correct.
42 Turning then to the principal complaint into which this debate feeds, the Appellant submits that the trial judge erred in referring to parts of the specification which were notable in their failure to refer to any movement of the anchor member and contrasting those with the frequent references to the movement of the impact reduction member. The Appellant argues that the parts of the specification referred to by the primary judge were all parts which concerned the embodiment in Figures 2 and 3.
43 However, as will shortly appear, the primary judge explicitly relied upon parts of the specification dealing with Figure 4 to reach the conclusion that the anchor member could not move. The analysis began at J [125] with the observation that 'No movement of the anchor member relative to the rock-face or the bore is described in the context of the functioning of the embodiments in Figures 3 and 4.' Her Honour then referred to a part of the specification which said:
In [the Figure 4] embodiment, however, the impact reduction member 5 is not configured for any significant movement relative to the plug member 2 upon impact by the falling broken drill rod section S. Rather, as the falling broken drill rod section S initially impacts or contacts the surface 9 of the tapered portion 8, the drill rod section S is gradually deflected towards and into contact with the opposite inner wall of the bore B. This contact generates friction which acts to brake the falling object and dissipate the impact. Again, therefore, the tapered portion 8 acts to cause gradual or extended transfer of impact loading from the drill rod section S to the anchor member 2. In particular, by extending the stopping distance for the falling drill rod section S (i.e. the distance travelled by the drill rod section S after initial impact) via the tapered portion 8, the impact force is again reduced significantly, such that the friction fit or interference fit of the anchor member 2 within the bore B can readily withstand the impact loading.
44 The trial judge referred to this passage at J [128] as part of her Honour's discussion of why the anchor member could not move. What is striking about the final sentence is its reference to the 'friction fit or interference fit' of the anchor member in the Figure 4 configuration which her Honour explicitly mentioned at J [128]. Thus, the contention that the trial judge overlooked the Figure 4 embodiment in concluding that the anchor member did not move is not correct.
45 The highest one can put the Appellant's case is its submission that the patent contains no express direction that the anchor member cannot move. However, as the trial judge was astute to observe, it just as equally lacks any suggestion that the anchor member should move: J [125]. And, in relation to the Figure 4 embodiment, the references to the 'friction fit or interference fit' of the anchor member are slim pickings indeed for a contention that the anchor member was intended to operate by travelling down the bore hole.
46 The next step in the argument was that her Honour had failed to bring to account the evidence that the embodiment in Figure 4 could travel down the bore. However, this was the evidence of Mr Davison and Dr Fuller to which I have referred and, as I have explained, was evidence of the theoretical retardant effect of the anchor member if driven down the bore hole rather than evidence that this was what the anchor member in Claim 1 was intended to do.
47 There is also the point made by the trial judge that the anchor member was to be 'fixed' when installed: J [145]. The Appellant's riposte to this is that it does not entail that the anchor member must remain fixed once struck by the falling drill rod section. However, there was no evidence for this view. As I have explained above, Dr Fuller denied it and whilst Mr Davison had initially suggested that the anchor member's fixation purpose ceased once the impact event began he retreated from this in the Joint Expert Report.
48 Next the Appellant submitted that the primary judge found at J [98] that the person skilled in the art would understand that the two components of the Safety System operate together to absorb the energy of the falling drill rod section. What her Honour said at J [98] was this:
In the context of the Patent, the person skilled in the art at the priority date would understand:
• The hazard posed by the falling broken drill rod is extreme and potentially fatal;
• The only way identified in the Patents to protect against the hazard is to stop the broken drill rod section from leaving the bore hole;
• The safety system of the Patents must stop the drill rod section falling from the bore each time;
• The impact force from a falling drill rod section, which is primarily a function of drill rod section size, weight, drop length and bore angle, is substantial, in the order of up to possibly hundreds of tonnes;
• A different safety system may be required for bores of different diameters;
• Stopping the falling drill rod section will involve absorbing the energy of and decelerating the falling drill rod section; and
• The one safety system will need to work for the all the potential forces up to the maximum possible impact force potentially experienced in a bore hole; i.e. whether the drill rod falls from a short distance or from the far end of the bore hole.
49 This is an overall description of how the Safety System works and does not descend into the detail of which component does what. In particular, it does not say that the anchor member is intended to generate frictional force by travelling down the bore. As such, it does not advance the Appellant's submission.
50 Thus there is nothing in the Appellant's submission that the person skilled in the art would understand that the anchor member described in the Figure 4 embodiment would decelerate a falling drill rod section as the anchor member moved downwardly against the frictional resistance of the bore wall. It follows that the Appellant is not correct to submit that the Figure 4 embodiment taught powerfully that the anchor member could travel down the bore. To the contrary, as the Respondents correctly submitted, this is precisely what it does not show.