Impro Ltd v Nesbit Evans Group Australia Ltd
[1996] FCA 1127
•23 Dec 1996
LIMITED DISTRIBUTION
CATCHWORDS
PATENT - claim for infringement - cross-claim for revocation - construction of Specification - application of established principles.
IMPRO LIMITED AND ARJO LIMITED v. NESBIT EVANS GROUP AUSTRALIA LIMITED
No. NG454 of 1994
No. NG365 of 1996
BEAUMONT J.
SYDNEY
23 DECEMBER 1996
IN THE FEDERAL COURT OF AUSTRALIA )
)
NEW SOUTH WALES DISTRICT REGISTRY ) No. NG454 of 1994
) No. NG365 of 1996
GENERAL DIVISION )
BETWEEN:IMPRO LIMITED
First applicant
ARJO LIMITED
Second applicant
ANDNESBIT EVANS GROUP
AUSTRALIA LIMITED
Respondent
AND BETWEEN: NESBIT EVANS GROUP
AUSTRALIA LIMITED
Cross-claimant
AND IMPRO LIMITED
First cross-respondent
ARJO LIMITED
Second cross-respondent
CORAM: BEAUMONT J.
DATE: 23 DECEMBER 1996
MINUTES OF ORDER
THE COURT ORDERS:
Direct the applicants to bring in draft short minutes of the orders to be made in accordance with the reasons for judgment.
Reserve costs.
Note:Settlement and entry of orders is dealt with in Order 36 of the Federal Court Rules.
IN THE FEDERAL COURT OF AUSTRALIA )
)
NEW SOUTH WALES DISTRICT REGISTRY ) No. NG454 of 1994
) No. NG365 of 1996
GENERAL DIVISION )
BETWEEN:IMPRO LIMITED
First applicant
ARJO LIMITED
Second applicant
ANDNESBIT EVANS GROUP
AUSTRALIA LIMITED
Respondent
AND BETWEEN: NESBIT EVANS GROUP
AUSTRALIA LIMITED
Cross-claimant
AND IMPRO LIMITED
First cross-respondent
ARJO LIMITED
Second cross-respondent
CORAM: BEAUMONT J.
DATE: 23 DECEMBER 1996
INDEX TO REASONS FOR JUDGMENT
INTRODUCTION 1
THE DESCRIPTION OF THE INVENTION IN THE SPECIFICATION 3
THE CLAIMS MADE IN THE SPECIFICATION 9
THE CASE SOUGHT TO BE MADE BY IMPRO AND ARJO IN CHIEF 14
(a) The evidence of Ms G.M. Brown 15
(b) The evidence of Mr R.A. Rigby 17
(c) The evidence of Dr H.L. Stark 22
- 2 -
THE CASE SOUGHT TO BE MADE BY NESBIT IN CHIEF 25
(a) The evidence of Dr T.R. Ackland 25
(b) The evidence of Professor N.L. Svensson 29
(c) The evidence of Dr K.Y. Cheng 36
(d) The evidence of Mr E.R. Scull 42
THE EVIDENCE OF IMPRO AND ARJO IN THEIR CASE IN REPLY 47
(a) The evidence of Mr R.A. Rigby 47
(b) The evidence of Dr H.L. Stark 56
THE EVIDENCE OF NESBIT IN ITS CASE IN REPLY 60
(a) The evidence of Professor Svensson 60
(b) The evidence of Mr E.R. Scull 69
(c) The evidence of Dr T.R. Ackland 88
(d) The evidence of Dr K.Y. Cheng 90
THE ORAL EVIDENCE GIVEN BY THE EXPERTS CALLED BY IMPRO
AND ARJO 96
(a) Ms G.M. Brown 96
(b) Mr R.A. Rigby 96
(c) Dr H.L. Stark 98
THE FURTHER EVIDENCE INCLUDING ORAL EVIDENCE, OF THE
EXPERTS CALLED BY NESBIT 102
(a)Professor Svensson (including his supplemental statement (Exhibit 3) and the evidence of Mr Hewett given in the course of the Court demonstration of the "Easi-Stand" 102
(b)Mr E.R. Scull 111
(c) Dr T.R. Ackland 114
(d) Dr K.Y. Cheng 115
CONCLUSIONS ON THE ISSUE OF LIABILITY IN THE CLAIM OF
INFRINGEMENT 117
(a)The construction of the Specification - what is,
relevantly, the invention claimed? 118
(b) Did Nesbit’s apparatus infringe? 145
NESBIT’S CROSS-CLAIM FOR REVOCATION 154
(a)Fair basing 155
(b) Ambiguity 157
(c) Inutility 158
(d) False suggestion and misrepresentation 161
(e) Obviousness 163
(f) Sufficiency 165
IN THE FEDERAL COURT OF AUSTRALIA )
)
NEW SOUTH WALES DISTRICT REGISTRY ) No. NG454 of 1994
) No. NG365 of 1996
GENERAL DIVISION )
BETWEEN:IMPRO LIMITED
First applicant
ARJO LIMITED
Second applicant
ANDNESBIT EVANS GROUP
AUSTRALIA LIMITED
Respondent
AND BETWEEN: NESBIT EVANS GROUP
AUSTRALIA LIMITED
Cross-claimant
AND IMPRO LIMITED
First cross-respondent
ARJO LIMITED
Second cross-respondent
CORAM: BEAUMONT J.
DATE: 23 DECEMBER 1996
REASONS FOR JUDGMENT
INTRODUCTION
Impro Limited ("Impro"), the first applicant and first cross-respondent, is the registered proprietor, by assignment, of Letters Patent for an invention (“the Invention”) being an invalid lifting hoist ("the Patent") for a term of 16 years commencing on 1 June 1984. The Patent is a convention patent.
Its priority date is 2 June 1983, the basic application having been filed on that date. Impro has granted Arjo Limited ("Arjo"), the second applicant and second cross-respondent, an exclusive licence under the Patent.
In these proceedings, Impro and Arjo claim that Nesbit Evans Group Australia Limited ("Nesbit"), the respondent and cross-claimant, has infringed the Patent by the sale of two versions of an invalid lifting hoist described in the proceedings as "Easi-Stand (Mark I)" (the 1994 proceedings) and "Easi-Stand (Mark II)" (the 1996 proceedings). Both the 1994 and the 1996 proceedings have been heard together by consent.
It is common ground that, for present purposes, there is no difference of any substantial kind between the two versions of Nesbit's hoist.
The applicants now seek injunctive and other relief.
Nesbit admits the sales of the "Easi-Stand", but says that it did not infringe the Patent.
Nesbit, as cross-claimant, claims (1) a declaration that the Patent is, and always has been, invalid, and (2) an order expunging it from the register. The grounds for revocation alleged by Nesbit are (1) inutility; (2) lack of fair basing; (3) ambiguity; (4) obviousness; (5) insufficient description; and (6) false suggestion and misrepresentation in obtaining the Patent.
Although there is no dispute about the primary facts, the parties are at issue as to the meaning of the Specification.
There is a substantial conflict in the expert opinion evidence called by each side, with the exception of the evidence of one expert witness, Ms G M Brown, an occupational therapist.
There is no real dispute between the parties as to the applicable legal principles. It is furt.her agreed that by virtue of the operation of s.233(1) of that Act, the Patents Act 1990 applies.
THE DESCRIPTION OF THE INVENTION IN THE SPECIFICATION
The complete Specification describes the invention as follows:
"The invention relates to the lifting of invalid patients, which term includes infirm. and disabled persons generally. It is particularly concerned with raising such patients from a sitting to a generally standing position, especially but not exclusively as part of a toileting procedure and with hoists adapted for so raising patients."
Its principal object is described thus:
"Even though mechanical aids have been available for some years to assist in the toileting task they have not been widely accepted and the task is normally still performed manually.... The lack of acceptance of the aids available stems from a number of disadvantages. A first disadvantage is. that most such aids are excessively complex to operate, so that busy nurses will not take the trouble to use them. A second disadvantage is that most aids do little or nothing to solve the problem of holding up a patient in such manner that the nurse can readily deal with clothing removal and cleaning of the patient; in fact such aids assume that the patient will not be wearing underclothing. A further disadvantage is that in addition to obstructing clothing removal the hoist aids which have been used or proposed in general tend to be uncomfortable for the patient if suitably held in the raised position for the requisite length of time.
Thus the principal object of the invention is to provide a method of lifting a patient from a sitting to a generally standing position, and hoists for so raising a patient, which largely overcome the disadvantages of prior methods and hoists. A specific object is to provide such a hoist which is relatively cheap to manufacture, which is of conveniently light and compact form, and which is simple to operate."
Another object is described as follows:
"Another object of the invention is to lift the patient in an almost identical manner to that employed in the usual manual lift but using simple mechanics to take all the strain out of the task, and to provide a hoist which will enable a single nurse to carry out the toileting task and thus, by its use, perform the work of three nurses at present and without risk of personal injury."
One aspect of the invention is described thus:
"According to one aspect of the invention the patient is lifted employing a hoist with a lifting arm arrangement presenting laterally spaced sling attachment points which are rigidly located laterally of the arm arrangement, the method of lifting comprising a procedure wherein the feet of the patient are positioned on a footplate or footrests with the legs below the knees substantially vertical, a sling is passed around the back of the patient underneath the arms thereof and, with said sling attached to said attachment points, said attachment points are moved
upwardly along a generally arcuate path relative to the position of the feet which arc has an effective radius comparable to the length of the thigh bones of the patient whereby to raise the latter to a generally standing position on said footplate or footrests whilst otherwise supported and laterally located by the sling, and said arc is centred about a lateral horizontal axis parallel to an imaginary line joining said attachment points and to imaginary lines respectively joining the centres of pivotal movement of the knee and hip joints of the patient, which axis remains fixed relative to said footplate or footrests and is disposed substantially directly above the heel position of the patient with the latter facing said axis.
Preferably the footplate or footrests remain stationary during the lifting movement with the lifting arm arrangement pivoting about a horizontal fixed axis. The knees of the patient may initially be located against knee abutment means of the hoist.
In the method of the invention the sling is passed around the back of the patient in the same manner as would be the arms of two nurses and it is preferably padded so that it simulates the muscular padding of the nurses' arms. As the radius of said arc is of comparable length to the thigh bones the lifting arm arrangement corresponds to the upper limb of a parallelogram the lower limb of which is provided by the thigh bone itself. The result is that the lifting is performed with no horizontal force tending to displace the knees. Preferably knee abutment means are mounted on the support structure so that the knees are not displaced but can remain at rest against the knee abutment means, the lower legs remain vertical thus ensuring that their own weight and half the thigh weight is supported by the feet on the footplate or footrests and there is no transference of this weight to be taken by the sling. This is an important feature contributing to patient comfort as it minimises the pressure on the body of the sling in lifting the balance, which may be approximately 60%, of the body weight." (Emphasis added).
The Specification further describes the invention by accompanying drawings illustrating two hoist embodiments and the
method of lifting. They include Figure 1, a rear perspective view of one embodiment, as follows:
Figure 6 illustrates three stages in the method of lifting as follows:
The Specification explains Figure 6 thus:
"Figure 6 diagrammatically illustrates the lifting method of the invention as applied with the illustrated hoists. The hoist is brought up to the seated patient as shown in Figure 6(a) so that the knee abutment means KA locates against the knees of the patient. With the hoist correctly located relatively to the seated patient P, the feet of the latter are placed on the footplate or footrest means F; and the support sling S is passed around the body of the patient P below the armpits and attached to the lifting arm LA of the hoist. Raising of the lifting arm LA, typically through an angle of about 60o, so that the sling attachment points AP move through an arc A about a centre C located relatively to and positioned above the means F, raises the patient P to the standing position shown in Figure 6(c). An intermediate position of the patient P, at the halfway point in the raising movement, is shown in Figure 6(b).
As Figure 6 clearly shows, a parallelogram lifting action occurs with a substantial part of the patient's body weight is at all times supported through the feet. The four pivot points of the parallelogram are respectively provided by the centre C, the sling attachment points AP, the knees and the hip joint of the patient P. To achieve such an approximately parallelogram movement, the length of the lifting arm LA when not adjustable is made approximately equal to the thigh length of an average person. Any necessary adjustment to suit short or tall patients can be achieved by using an appropriate effective length of sling S. (Emphasis added).
The lifting of an infirm or severely disabled person is illustrated in full lines in Figure 6, as shown the knee region engaging the abutment means KA at all times even when in the final standing, and slightly backwardly-inclined, position. However, patients with sufficient muscular strength will involuntarily straighten their legs during lifting so that, in the final position the body is completely straight between the footrests or footplate F and the sling S. Thus for these patients the abutment means KA merely provide location at the initial stage of the lift." (Emphasis added).
THE CLAIMS MADE IN THE SPECIFICATION
Some 31 claims are made in the Specification. Seven (1‑5, 28 and 31) are method claims. Claims 1-5, 7 and 28-31 are not relied on by the applicants in claiming infringement, but are relied on by the applicants in answer to the cross-claim for revocation. In support of their infringement action, Impro and Arjo place particular reliance on claims 6 and 11, which will be set out below.
Claims 1-5 should first be mentioned as follows:
"1.A method of lifting a patient from a seated to a substantially standing position employing a hoist with a lifting arm arrangement presenting laterally spaced sling attachment points which are rigidly located laterally of the arm arrangement, comprising a procedure wherein the feet of the patient are positioned on a footplate or footrests with the legs below the knees substantially vertical, a sling is passed around the back of the patient underneath the arms thereof and, with said sling attached to said attachment points, said attachment points are moved upwardly along a generally arcuate path relative to the position of the feet which arc has an effective radius comparable to the length of the thigh bones of the patient whereby to raise the latter to a generally standing position on said footplate or footrests whilst otherwise supported and laterally located by the sling, and said arc is centred about a lateral horizontal axis parallel to an imaginary line joining said attachment points and to imaginary lines respectively joining the centres of pivotal movement of the knee and hip joints of the patient, which axis remains fixed relative to said footplate or footrests and is disposed substantially directly above the heel position of the patient with the latter facing said axis.
A method according to claim 1, wherein said lateral axis is disposed at a fixed height and said lateral axis is maintained stationary relatively to said footplate or footrests during lifting movement.
A method according to claim 1 or claim 2, wherein said sling is of padded form and the width thereof is such that when the patient is raised to the standing position a lower portion of the trunk of the patient is accessible for clothing removal and/or treatment, toileting and the like.
A method according to any one of the preceding claims, wherein the hoist is initially positioned with the knees of the seated patient located against knee abutment means of the hoist.
A method according to claim 3, wherein the weight of the patient is supported solely by said sling and by the footplate or footrests whilst the patient is being lifted from the seated to the standing position."
Claims 6-27 are made in respect of a patient hoist in these terms:
"6.A patient hoist comprising an upstanding support structure, a lifting arm arrangement projecting from the support structure and providing laterally spaced attachment points for the attachment of a body support sling positioned around the back of a seated patient below the arms thereof, said attachment points being rigidly located laterally of the arm arrangement which is pivoted about a horizontal axis with the attachment points disposed at a radius comparable to the average length of a human thigh bone, a footplate or footrests on or fixed relatively to the support structure, and a lifting mechanism operative to raise the lifting arm arrangement in such manner that the attachment points thereof move along a generally arcuate path centred on a lateral axis parallel to an imaginary line joining said attachment points, such movement of the lifting arm arrangement being sufficient to raise the patient to a standing position with the feet of the latter supporting a substantial part of the total body weight of the patient while the latter is also supported and laterally located in the standing position by said sling. (Emphasis added).
A hoist according to claim 6, wherein said lifting arm arrangement is mounted on said support structure for solely pivotal movement about said horizontal axis by said lifting mechanism, and said support structure with said horizontal axis disposed substantially directly above the footplate or footrests.
A hoist according to claim 7, wherein said lifting mechanism comprises an operating lever pivotally mounted about a horizontal axis on said support structure on the side thereof remote from said lifting arm arrangement, and a mechanical coupling between said operating lever and said arm arrangement provides a mechanical advantage.
A hoist according to any one of claims 6 to 8, wherein said support structure is mounted on a mobile chassis comprising spaced chassis side members, said chassis being open at the front between said side members, and said support structure is mounted adjacent the rear of the chassis and comprises a central upper column portion on which said arm arrangement and said lifting mechanism are mounted, and a lower portion of inverted U-shape with side limbs respectively mounted on the chassis side members and an intermediate limb on which said column portion is mounted.
10.A hoist according to any one of claims 6 to 9, wherein knee abutment means are mounted on said support structure for location of the knees of the patient.
11.A patient hoist comprising an upstanding support structure for example a column, a pivotal lifting arm arrangement projecting from one side of the column and providing laterally spaced attachment points for the attachment of a padded body support sling passed around the back of a patient below the arms thereof with the attachment points rigidly located laterally of an arm arrangement which is pivotal about a fixed horizontal axis parallel to an imaginary line joining the attachment points which are disposed at a radius comparable to the average length of a human thigh bone, knee location abutment means on the support structure, a footplate or footrests on or attached to the support structure and a lifting
mechanism operative to raise the lifting arm arrangement about said horizontal pivot axis through an angle sufficient to raise the patient, with the knees of the latter located against said abutment means, to a standing position on the footplate or footrests with the feet of the patient supporting a substantial part of the total body weight of the latter whilst supported from behind and laterally located by the sling. (Emphasis added.)
12.A hoist according to claim 11, wherein the support structure is mounted on a mobile chassis over which the lifting arm arrangement projects, said chassis being of U-shaped form open at the front with the support structure mounted adjacent the rear of the chassis which has side members of adjustable spacing.
13.A hoist according to claim 12, wherein the support structure comprises an upstanding column mounted on the chassis which has a cross member on which the column is centrally mounted, said footrests being mounted on the cross member on either side of the column.
14.A hoist according to claim 11 or 12, wherein the support structure comprises an upper central column portion and a lower portion of inverted U-shape which is mounted on the chassis.
15.A hoist according to claim 14, wherein said lower portion of the support structure has spaced upright members respectively mounted on the chassis side members and said footplate extends between the chassis side members.
16.A hoist according to claim 15, wherein the chassis side members are pivotally adjustable about the axis of said upright members of said lower portion of the support structure.
17.A hoist according to any one of claims 12 to 16, wherein the arm arrangement incorporates hand grips for the patient.
18.A hoist according to any one of claims 12 to 17, wherein said lifting mechanism is mechanical and manually operated with an operating lever pivotally mounted at the side of the support structure opposite to the lifting arrangement.
19.A hoist according to claim 18, wherein a mechanical linkage between the operating lever and the lifting arm arrangement provides a mechanical advantage.
20.A hoist according to claim 19, wherein the operating lever moves downwardly through approximately 180o to effect the arm lifting movement.
21.A hoist according to claim 20, wherein the arm lifting movement is in the range of 60-65o.
22.A hoist according to any one of claims 19 to 21, wherein said mechanical linkage includes an over-centre device such that the lifting mechanism is self-locking in the arm raised position.
23.A hoist according to any one of claims 18 to 22, wherein a clip or catch is provided on the support structure to retain the operating lever against accidental displacement when in a patient raised position.
24.A hoist according to any one of claims 12 to 23, wherein the lifting arm arrangement comprises an inner end central portion directly coupled to the lifting mechanism and two laterally spaced outer end portions provided with end sling attachment means and which are spaced apart by a distance which approximates to the shoulder width of a typical patient.
25.A hoist according to claim 24, wherein said inner and outer arm portions are articulated for arm height adjustment, said adjustment employing an eccentric rotary cam.
26.A hoist according to any one of claims 12 to 25, wherein the lifting arm arrangement is of telescopically adjustable length.
27.A hoist according to any one of claims 18 to 26, wherein damping means are provided operative to lower the patient gently if the operating lever is inadvertently released during raising or lowering of the patient."
Claim 28 is as follows:
"28.A method of lifting a patient from a seated to a substantially standing position, substantially as herein described with reference to Figure 6 of the accompanying drawings."
Claims 29 and 30 are made in respect of a hoist for lifting a patient from a seated to a substantially standing position as indicated in Figures 1 to 5 depicted in the accompanying drawings.
Finally, claim 31 is for a method substantially as earlier described with reference to any one of the embodiments as shown in the accompanying drawings.
It is common ground that the Patent is a combination patent, in that the utility of the invention is said to arise from the combination of various integers.
THE CASE SOUGHT TO BE MADE BY IMPRO AND ARJO IN CHIEF
In order to understand the issues that ultimately arise for resolution, it will be necessary to describe the expert opinion evidence called by each side. There was a substantial body of evidence tendered in the course of the trial, some of it in affidavit form, some of it in the form of oral testimony. I was considerably assisted in my understanding of the case by this evidence, which has not proved easy to state in a compendious fashion. In the circumstances, I have set out the substance of the views of the experts quite fully as it well demonstrates the apparent depth and complexity of the main issues, especially in the approach taken to the interpretation of the meaning of several contentious aspects of the Specification.
Impro and Arjo called, in their case in chief, several experts whose evidence was, so far as is presently material, to the following effect:
(a) The evidence of Ms G.M. Brown
The affidavit of Genifer Mary Brown, occupational therapist, sworn 21 December 1995, was relevantly to the following effect.
In the course of her career, since 1974, Ms Brown has become familiar with the different mechanical devices available for lifting disabled patients.
The choice of method used to lift a disabled person depends on the extent of his or her disability, the nature of the lifting problem, the environment and the operator.
In the early 1980s, there was resistance from patients, nursing staff and home carers to the introduction of mechanical lifting hoists. Such hoists were perceived to be time consuming, difficult to use and, for the patients, sometimes frightening.
The general categories of hoists available are (1) fixed to floor hoists; (2) fixed overhead hoists; and (3) mobile hoists.
Mobile hoists are used for several different lifts, in different rooms of a house, or for different patients in a nursing home. Mobile hoists are mechanical, hydraulic or electrical in operation; slings, fixed seats or support bars are used to support the person being lifted.
The mobile hoists known to her in 1983 consisted of a base on casters, a mast and a boom and spreader bar system from which the patient was suspended in a sling or set of slings. The patient was cradled in a reclined position and suspended under the spreader bar.
By 1985, mobile hoists with fixed seats were available in Australia. Their operation involved lifting the whole of the patient’s body, either by use of slings or stretchers, or, in the case of Arjo’s “lift ride chair”, by raising the seat on which the patient was seated by hydraulic means. The Arjo-Mechanaids “Stella” hoist, available in this country from 1985, was designed for the specific lifting problem of toileting. It was unusual because, instead of a boom or spreader bar system, it had a foot platform and a back support or sling, which supported
the patient whilst he or she was being lifted into a semi-standing, or standing, position. No other hoist then used this method of lifting and, in the semi-standing position an attendant could readily adjust clothing. The “Stella” hoist could only be used by clients able to co-operate with the lifter and take some weight through the legs. Prior to the introduction of the “Stella” to this country in 1985, there was no other mechanical hoist which lifted the patient to a standing position.As has been mentioned, none of this evidence was seriously challenged.
(b)The evidence of Mr R.A. Rigby
Ralph Anthony Rigby, an industrial design engineer, swore several affidavits in each proceeding, some in chief, others in reply.
In his affidavit sworn 28 March 1995, Mr Rigby said that on inspection of the “Easi-Stand Mark I”, he observed the following: (1) an upstanding support structure; (2) a lifting arm arrangement with grips, projecting from the support structure; (3) laterally spaced attachment points on each of the lifting arms; (4) (on operation) the arm arrangement pivoted about a horizontal axis; (5) the attachment points were disposed at a radius which, in Mr Rigby’s opinion, was “comparable to the average length of a human thigh bone”; (6) a foot plate or foot rest fixed to the support structure; (7) an inner end central portion directly coupled to a lifting mechanism; (8) knee abutment means mounted on the support structure; and (9) a mobile chassis of u-shaped form open at the front with side members of adjustable spacing.
Photographs showing the “Easi-Stand” in operation were tendered (part of Exhibit D) as follows:
In Mr Rigby’s opinion, the attachment points on the lifting arms of the “Easi-Stand” would, when the device was in use, move along “an arcuate path centred on a lateral axis parallel to an imaginary line joining the attachment points”. Further, in his opinion, the lifting arm arrangement of the “Easi-Stand” lifts the patient to a “substantially standing position”.
The phrase used in the Patent Specification “comparable to the average length of a human thigh bone” does not, in his view, signify a precise measurement or a precise range of measurements. In his opinion, the purpose of using a lifting arm of comparable length to the thigh bone of the average patient is to produce “an approximately” parallelogram lift; and this ensures that the sling is moved forward by an appropriate amount as the patient is lifted from a seated position. From an examination of photographs of the “Easi-Stand” in use, Mr Rigby could “see a very clear parallelogram”.
The Patent Specification indicates to Mr Rigby that the parallelogram “need only be approximate”. He noted, in this connection, that different sized slings can be used to accommodate different sized patients. He further noted, in this regard, that according to the Patent Specification, the lower resting position of the arm portions is adjustable over a large range of angles.
Mr Rigby went on (in para. 16.2 of this affidavit) to express the opinion that the phrase in the Specification “comparable to the average length of a human thigh bone” did not “signify any particular narrow range. All that is required is that an approximately parallelogram lift is achieved which [may be] observed ...[in] the “Easi-Stand”.”
In his affidavit sworn 28 May 1996, Mr Rigby said that he inspected an “Easi-Stand Mark II”.
He measured the length of its lifting arm, from the pivot point to a point bisecting an imaginary line drawn between the sling attachment points on the two arms to be approximately 660mm.
Observing the equipment in operation, Mr Rigby noted only a few differences in comparing it with the “Mark I” version. They included the length of the lifting arm (about 80mm longer than “Mark I”) and the consequent placement of the pivot point of the lifting arm in relation to the patient. The upstanding support structure was angled backwards to accommodate the slightly longer lifting arm.
Mr Rigby observed that the movement of the lifting arm of “Mark II” followed an arcuate path centred on a lateral axis parallel to an imaginary line joining the attachment points. The patient “was lifted to a substantially standing position by the forward, lifting movement which approximates to a more or less parallelogram lift”.
Notwithstanding the longer lifting arm on “Mark II”, Mr Rigby “could see no appreciable change” in the configuration of the lift. He saw “no mechanical or biomechanical reason” for any difference between “Mark I” and “Mark II”.
Referring to the opinion, mentioned above, expressed in para. 16.2 of his affidavit sworn on 28 March 1995, Mr Rigby went on to express the view, in his affidavit sworn on 28 May 1996, that the length of the lifting arm of the “Easi-Stand Mark II” is “comparable to the average length of the human thigh bone”.
(c)The evidence of Dr H.L. Stark
Dr Hugh Lithgow Stark, a consulting engineer and Senior Lecturer (part-time) in the School of Mechanical Engineering, University of New South Wales, swore several affidavits in each proceeding, some in chief, others in reply.
In his affidavit sworn 27 May 1996, Dr Stark, upon observation of the “Easi-Stand Mark II” identified the following features: (i) an upstanding support stand; (ii) a raiseable lifting arm projecting from the support stand; (iii) attachment points on the lifting arm on which to attach a body sling to fit around the patient’s body; (iv) a foot plate attached to the upright stand; and (v) a knee pad above the foot plate.
Dr Stark viewed the operation of “Easi-Stand Mark II” as involving a lifting movement which “approximates a parallelogram lift of the patient”. In his opinion, “the essence of this ‘more or less’ parallelogram movement” is “to move the patient’s torso both upwards and forwards such that with no foot movement, the torso moves from a seated position, forwards and upwards to a near standing position without moving the feet”. In his view, the hips move up and forward by a similar distance to the sling attachment points.
Dr Stark went on to refer to an earlier affidavit, sworn by him on 7 December 1995, in which he expressed opinions as to the meaning of the Patent Specification and as to the operation of the “Easi-Stand Mark I”.
In paragraph 10 of the earlier affidavit, Dr Stark said:
“Given the descriptions in the specification and the embodiment of the invention disclosed in Figure 6, I am of the view that the parallelogram movement referred to in the specification is intended to be very much an approximation of a parallelogram and there is no requirement that the opposites sides of the so called parallelogram be of equal length or precisely parallel. It can be seen from Figures 6(a) and 6(b) of the specification that the lifting arm in those figures is not parallel to the thighs of the patient and no two sides of the notional parallelogram drawn on Figures 6(a) and 6(b) according to the description in the specification are equal in length. In my view the specification teaches that the aim of the approximate parallelogram lifting movement is to lift the patient’s body and move it forward on top of the feet. To this end the length of the lifting arm is comparable to the length of the thigh of the patient in that it is not, say, three times as long as the patient’s thigh. It appears to me that a lifting arm of the order of twenty percent longer than the thigh bone could well be described as comparable to the length of the thigh bone, given its required function of moving the body forward as well as raising it. In contrast, if the lifting arm, being approximately parallel to the thigh bone were three or four times the length of the thigh bone the body of the patient would not be pulled forward on top of the feet, or not significantly so, so that the raised body would not reach the desired near vertical position.”
In his affidavit sworn on 27 May 1996, Dr Stark went on to say that the opinions expressed in his earlier affidavit concerning the “Easi-Stand Mark I” applied also to the “Mark II” version. He then said:
“The specification of the Patent tells me that the purpose of the approximate parallelogram lifting movement is to lift the patient’s body and move it forward on top of the feet. This is the movement I witnessed in the operation of the Easi-Stand Mark II.
In my opinion the length of the lifting arm of the lifting hoist described in the Patent will be ‘comparable to the average length of the human thighbone’ according to the invention described in the Patent if it achieves an approximate parallelogram lifting movement and thus moves the patient forward and up. If the lifting arm were not at least comparable to the average length of the human thighbone the forward component of the lifting movement would not be achieved.”
THE CASE SOUGHT TO BE MADE BY NESBIT IN CHIEF
Nesbit also called, in its case in chief, several experts whose evidence, so far as is presently relevant, is to the following effect:
(a) The evidence of Dr T.R. Ackland
Dr Timothy Robert Ackland, Senior Lecturer, Department of Human Movement, University of Western Australia, swore several affidavits in each proceedings, some in chief, others in reply.
In his affidavit sworn on 13 June 1995, Dr Ackland expressed the opinion that the references in the Patent
Specification to the length of “thigh bone” signify “a precise measurement or a precise range of measurements of the ‘human thigh bone’ in relation to the area of use of the potential product as contemplated by [the] ...Patent.”
Dr Ackland was further of the opinion that a number of methods may be used to determine the relationship between a person’s height and the length of his or her thigh bones. He criticised the use of regression equations on the ground that they could only be applied for subjects with morphological characteristics, including body size, which are similar to those from whom the equation was derived.
In his view, a more logical and valid approach lies in the consideration of recent population census and survey data. One method is to undertake a survey of a randomly selected group of individuals. Their femur length and height should be measured. The measurements can then be compared across the whole survey group to identify the existence, extent and nature of any relationship between the two measurements. Dr Ackland knows of at least two surveys that were so conducted: (1) A survey reported in Pheasant (1988), derived in relation to two British surveys, conducted in 1981 and 1984; (2) An American survey by NASA of Japanese adults (1978), also reported in Pheasant (1988). Dr Ackland extracted the following representative femur lengths from Pheasant (1988): In the
case of British adults (19-25 years) the representative lengths were, in the case of the male, 490mm (50th percentile) and 525mm (95th percentile); and in the case of the female 415mm (50th percentile) and 440mm (95th percentile). In his opinion, this provided representative femur lengths for both males and females for the 50th percentile which, assuming a normal distribution, is the sub population average, and the 95th percentile, below which 95 per cent of the population fall.
Dr Ackland expressed the opinion that, for Australian purposes, the survey results in relation to British adults are the most appropriate reference data, since the majority of the Australian population is Caucasian and of European descent, and no comparable norms exist specifically for Australian adults; and “significant” differences and variations in data occur in different racial groups. In his opinion, that the possibility that an Australian adult may possess a femur length of 580mm (being the length of the distance between the point at which the sling attaches to the lifting arm of the “Easi-Stand Mark I” and the axis point of that arm) is “extremely rare.”
Dr Ackland went on to describe an alternative method of identifying the relationship between height and femur length, known as the “Phantom Stratagem,” by which a series of calculations is undertaken, each providing for a
different proportionality factor with regard to the relationship between the person’s femur length and his or her height. By using this method, Dr Ackland calculates that a femur length of 580mm would correspond to a subject height of 238.6cm or 7 feet 10 inches, a height exceeding the range of “clinically normal” and exceedingly rare.
Using what he described as a “conservative approach (that is, in attempting to achieve the lowest possible stature for a given femur length)”, Dr Ackland selected a “proportionality factor” so as to make any allowance for a subject having an abnormally large femur. By this calculation, a subject with a femur length of 580mm would have a height of 202.2cm or 6 feet 7½ inches. According to Pheasant, such a height is significantly greater than the 95 percentile of stature among both Caucasian and Asian adults. In Dr Ackland’s opinion, in considering what could be reasonably regarded as the average length of the human thigh bone, regard must be had to a range of measurements because of height differences within the population and the variation in the relationship between femur length and height. Dr Ackland went on to express this conclusion:
“However, even after having regard to these factors, and assessing the ‘average length of the human thigh bone’ in terms of a range of measurements generally found in the population (so as to exclude those who are extraordinarily tall or short), I regard the measurement of 580mm as not falling within the range of measurements which could be reasonably described as
being comparable to the average length of the human thigh bone.”
(b) The evidence of Professor N.L. Svensson
Professor Noel Levin Svensson, Visiting Professor in the Department of Safety Science and in the Centre for Biomedical Engineering, University of New South Wales, swore several affidavits both in chief and in reply.
By his affidavit sworn 21 June 1995, Professor Svensson expressed the opinion that the following features of the invention were not embodied in “Easi-Stand Mark I”: (1) In claim 1: (a) the feature described as “...which arc has an effective radius comparable to the length of the thigh bone of the patient...”; and (b) the feature described as “...which axis... is disposed substantially directly above the heel position of the patient with the latter facing said axis...” (2) In claim 6: the feature described as “...a lifting arm arrangement... with the attachment points disposed at a radius comparable to the average length of the human thigh bone...” (3) In claim 11: the feature described as “...a pivotal lifting arm... providing laterally spaced attachment points... which are disposed at a radius comparable to the average length of the human thigh bone...”
Professor Svensson measured the length of the distance between the point at which the sling attaches to the lifting arm of the “Easi-Stand Mark I” and the axis point of that arm, as 580mm.
Professor Svensson observed that, when the “Easi-Stand Mark I” is in use, the heel position of the patient is displaced at a significant distance posteriorly from a position directly below the axis of the lifting arm.
Professor Svensson was of the opinion that some flexibility should be accorded to the words in the Patent Specification “comparable to the average length of the human thigh bone” and to the words “comparable to the length of the thigh bone of the patient;” and that these words suggest a range of measurements, based on the length of thigh bones of patients likely to use the equipment, rather than, say, of an “average” patient. The words indicate that the lifting arm... is to have a length “which is within a range of lengths of thigh bones commonly found in the population for which the... hoist is designed”.
Using Dr Ackland’s figures of 95th percentile lengths of 440mm (female) and 525mm (male), Professor Svensson calculated that the distance of 580mm exceeded 525mm by 10% and 440mm by 32%. The middle point of this range (482.5mm) was exceeded by 580mm by 20%.
Professor Svensson does not regard a measurement of 580mm as reasonably falling within the range of measurements suggested by the terms “comparable to the length of the thigh bone to the patient” or “comparable to the average length of the human thigh bone”.
Professor Svensson regards the following features: (1) the length of the distance between the axis of the lifting arm, and the sling attachment points; and (2) the location of the feet of the patient - as important for the operation of the patented invention.
Professor Svensson regards the parallelogram mechanism as the essence of the patented invention. That mechanism is supplied by the following features: (a) a line between the hips and knees of the patient; (b) a line between the patient’s knees and the pivot point of the lifting arm; (c) a line between the pivot point of the lifting arm and the sling attachment near the patient’s armpits; and (d) a line between the sling attachment hooks and the patient’s hips.
In Professor Svensson’s opinion, the axes of the parallelogram mechanism are provided by: (1) the patient’s hips; (2) the patient’s knees; (3) the pivot point of the
lifting arm; and (4) the sling attachment points/patient’s armpits.
In order for the parallelogram mechanism to operate, several features must, in his opinion, operate correctly and in accordance with the Patent Specification. These features each combine to ensure that the lifting force of the hoist is directed vertically, and passes through the centre of gravity of the patient’s torso, head and upper extremities, taking into account a portion of the weight of the thighs which is supported directly at the hip joints.
Professor Svensson is of the opinion that the proper operation of the “parallelogram motion” requires that: (1) the torso be as vertical as possible, achieved through the use of the shortest possible sling, so that the torso is kept as close as possible to the sling attachment points; (2) the length of the lifting arm is approximately equal to the length of the thighs; and (3) the patient’s arms are raised to a more or less horizontal position, in order to bring the patient’s centre of gravity forward of a line joining the hip and shoulder joints.
In Professor Svensson’s opinion, when the above conditions are fulfilled, there will be: (i) no tendency for the patient’s knees to be displaced in a horizontal direction; (ii) no need to provide for a knee support to
prevent such displacement; and (iii) no need for the patient to stiffen his or her knees and rely on a friction force of the footplate to counteract a horizontal movement of the patient’s lower legs.
Professor Svensson is of the opinion that, since the provision of a knee support in the Patent Specification is suggested only for assistance to, and safety of, the patient, “the provision of a knee support to prevent forward displacement of the knees cannot be regarded as important to the operation of the invention and does not add materially to the working of the invention”.
Professor Svensson acknowledges that the three aspects of the invention described in the Patent Specification being claims 1, 6 and 11 respectively, “do not specifically refer to the parallelogram mechanism referred to [elsewhere] in the Specification. However, the features referred to in my analysis of the [requirements for the proper operation] of the parallelogram mechanism... are incorporated in the description of the three aspects of the invention in claims 1, 6 and 11 respectively.” This provides the basis for his view that the Specification requires that the length of the lifting arm of the hoist be of a length comparable to the length of the thigh bone of the patient and the basis of his views (i) that this feature is of special importance in the operation of the
invention; and (ii) that the location of the pivot point of the lifting arm as being disposed substantially directly above the heel position of the patient is also an important feature of the invention.
Having observed the “Easi-Stand Mark I” device in operation, Professor Svensson is of the opinion that it provides for a lifting mechanism which “is different in substance from the lifting mechanism described in claims 1, 6 and 11 of the Patent.” In his view, whereas claims 1 and 6 do not require knee support to prevent lateral (anterior/posterior) displacement of the patent’s knees, the lifting motion of the “Easi-Stand” requires a significant force (of the order of one-third of body weight) between the patient’s knees and the knee support. His opinion is that the “Easi-Stand” is unable to operate effectively without either (i) the provision of a significant restraint of the patient’s knees; or (ii) the ability of the patient to stiffen his or her knees and rely on a friction force between the footplate and the patient’s feet to counteract the horizontal component of the lifting force required.
Professor Svensson is further of the opinion that the lifting mechanism of the “Easi-Stand” has five lines: (1) a line between the patient’s hips and knees; (2) a line between the knees and the pivot point of the lifting arm;
(3) a line between that pivot point and the sling attachment hooks; (4) a line between those hooks and the armpits; and (5) a line between the armpits and the hips.
In his opinion, this cannot be described as a parallelogram type lifting motion: whereas such a motion requires that the opposite sides of the parallelogram are of the same length, and remain parallel throughout the lifting motion, the “Easi-Stand” motion is made up of sides of unequal length, none of which are, or remain, parallel to each other.
In Professor Svensson’s opinion, the following features of the “Easi-Stand” contribute to this significant difference in the lifting mechanism:
“(1)the provision of the sling, which suspends the patient at a distance from the sling attachment hooks which is significant when compared with the length of the other sides...;
(2)the location of the patient’s knees and feet, which are substantially displaced laterally from a point directly below the pivot point of the lifting arm. This results in the line between the patient’s knees and the pivot point of the lifting arms being not parallel to any other side of the lifting mechanism...;
(3)the length of the lifting arm of the Easi-Stand, which bears no relationship to the length of the thigh bones of a patient, and in fact is substantially longer than the thigh bones of patient for whom this equipment is designed.”
(c) The evidence of Dr K.Y. Cheng
Dr Kam Yuk Cheng, Lecturer in the Department of Mechanical & Materials Engineering, University of Western Australia, sworn several affidavits in chief and in reply.
In his affidavit sworn on 20 June 1995, Dr Cheng expressed the opinion that a distance of 580mm (being his measurement of the distance between the points of attachment of the sling to the lifting arm of the “Easi-Stand Mark I” and the arm’s pivot point) does not reasonably fall within a range of measurements suggested by the terms “comparable to the length of the thigh bone of the patient” or “comparable to the average length of the human thigh bone.”
Dr Cheng also measured the distance between the position of the patient’s heels on the “Easi-Stand Mark I” and the point placed directly beneath the axis of the lifting arm, yet being directly lateral to and forward of the patient’s heels, as being 360mm. In his opinion, the axis of that lifting arm is not “disposed substantially directly above the heel position of the patient with the latter facing said axis” as described in claim 1 of the Patent Specification.
In Dr Cheng’s view, these two features of the “Easi-Stand (Marks I and II)” make the lifting mechanism embodied
in [them] different as a matter of substance to the lifting mechanism described in the claims of the Patent.”
In his opinion, the Patent Specification describes the “importance and essentiality” of the length of the lifting arm of the invention as being comparable to the length of the thigh bone of a patient in producing an “approximately parallelogram lift” or a “more or less parallelogram motion.” In his experience of engineering specifications, a “parallelogram motion” is understood to comprise a four sided lifting motion wherein the opposite sides of the configuration are of equal length and remain parallel to each other during the whole extent of the lifting motion; and, in his opinion, to achieve an “approximately parallelogram lift” consistently with the Patent Specification claims, it is a necessary condition that the length of the lifting arm be approximately equal to the length of the thigh bone. In his view, the horizontal component of the lifting force is less in the “Easi-Stand” than in the invention described in the Patent Specification, and the “Easi-Stand” vertical component is greater.
In Dr Cheng’s opinion, the effect of the substantial displacement of the position of the patient’s heels from a point directly beneath the lifting arm is that it also significantly alters the “Easi-Stand” lifting mechanism
from that described in the claims in the Patent Specification; and the effect of this displacement, in conjunction with the provision of a knee abutment means at a point substantially directly above the position of the patient’s heels, is to cause the knee abutment means to operate as a fulcrum. In his view, throughout the "Easi-Stand’s" lifting motion, there is significant horizontal force from the patient’s knees onto the knee pad; whereas in the parallelogram motion described in the claims in the Patent Specification, there is no tendency to displace the knees laterally; and in any event, the Specification makes it clear that the use of a knee support is optional only. In his view, this is a difference of substance between the "Easi-Stand" and the claims of the Patent.
In Dr Cheng’s opinion, Mr Rigby’s descriptions of his understanding of what comprises a “parallelogram lifting motion” are so broad that they cover all forms of lifting motion of an object which progresses through an arcuate path. Dr Cheng is of the view that a necessary result of lifting an object through an arcuate path is that there will be lateral displacement of the object as it is being lifted; and the configuration of the lifting device, particularly the lengths of the lifting arm and of the arc, will determine the extent of the displacement.
Dr Cheng is of the opinion that Dr Ackland’s evidence does not indicate the average lengths of British male and female thigh bones; what Dr Ackland presents is the 50th percentile value of these two groups; if the distributions were not skewed or multi-nodal, then the 50th percentile and the average would be the same.
With reference to Mr Rigby’s view that a radius length of 580mm is “comparable” to a femur length which lies between 415mm and 490mm, Dr Cheng, assuming an average of approximately 450mm is of the opinion that this is not “comparable” with 580mm.
In Dr Cheng’s opinion, the meaning of “parallelogram motion” as described in the Patent Specification may be depicted as follows:
Dr Cheng is of the view that the “parallelogram motion”, as described by the claims in the Patent Specification, is provided by the following features:
(1) the lifting arm of the invention; and
(2) the patient’s thigh bone,
being “comparable” in length, and at all times remaining parallel throughout the lifting process when in operation; and
(3)a line between the patient’s knees and the pivot point of the lifting arm; and
(4)a line between the sling attachment hooks and the patient’s hips,
as being of “comparable” length, and at all times remaining parallel throughout the lifting motion.
Dr Cheng is of the opinion that it is impossible to find a precise description of the invention in the Patent Specification because no finite range of measurements can be there identified to enable a skilled addressee to determine what is “comparable” to the length of the
patient’s thigh bone or to the average length of a thigh bone.
In his affidavit sworn on 7 September 1995, Dr Cheng described the results of tests carried out by using the "Easi-Stand Mark I". He is of the opinion that if a patient had a femur length approximately equal to the length of the lifting arm of the "Easi-Stand" (i.e. 580mm) and that patient was lifted by use of that device, the lift would not be achieved by use of a parallelogram as described in the Patent Specification; and that there would be a considerable lateral force displaced by the patient’s knees against the knee pad throughout the lifting phase; and that the lift could not be safely achieved without the use of a knee abutment means, to meet and counteract that force.
(d) The evidence of Mr E.R. Scull
Mr Edward Royston Scull, bioengineer, Department of Medical Physics, Royal Perth Hospital, swore several affidavits, both in chief and in reply.
By his affidavit sworn on 21 September 1995, Mr Scull expressed the opinion that the Patent Specification teaches, in respect of its parallelogram lifting mechanism, that the respective sides of that mechanism must be of
equal length and parallel. He is further of the opinion that the Specification teaches that the lift is achieved with no lateral force, or no force of abutment between the knees and the abutment pad; and that the abutment pad acts as a positioning device only to ensure that the knees are aligned above the feet (i.e. the ankle joints).
Mr Scull interprets the Specification to teach the need for adjustability of the device to accommodate variation in the patient’s stature, so that it is a critical parameter of the patented mechanism that the length of the lifting arm be adjustable so as to: (i) accommodate variations in patient height (i.e. length of thigh); and (ii) maintain a parallelogram lifting mechanism for each patient.
In Mr Scull’s experience, design for 95 per cent of the overall population (i.e. 2.5 percentile females and 97.5 percentile males) is common practice for this type of equipment, giving a range of lengths of thigh bone from 350.5mm (2.5 percentile females) up to 515.6mm (97.5 percentile males); that is, the lifting arm would need to be adjustable by 165.1mm (i.e. the difference between 515.6mm and 350.5mm). Moreover, in Mr Scull’s experience, the following is usually indicated: (i) incremental adjustments in the order of 25mm in the case of this type of equipment (i.e. patient hoists, wheelchairs, commodes);
and (ii) some degree of inaccuracy in measuring the length of a femur, indicating a maximum error of 39mm.
Mr Scull interprets the Patent Specification to teach that the arm length be adjustable to be within 12.5mm of the measured length of the thigh. But, in his opinion, it is more likely that the accuracy of measurement would be within a range determined by the overall standard deviation of the data collated by a number of operators of varying training and skill, in which case the skilled addressee would expect the arm length to be within 42.8mm (i.e. 30.32mm +/- 12.5mm) of the actual length of the thigh bone.
In Mr Scull’s opinion, the Patent Specification described a device and method which provides for the parallelogram lifting mechanism to be relatively precise when used with patients of differing heights, such to be achieved by providing a high degree of adjustment of the dimensions of the parallelogram to meet the specific dimensions of the patient; and the degree of inaccuracy of the parallelogram mechanism would be in the order of 30.32mm of the length of the thigh bone of the patient being lifted.
In Mr Scull’s opinion, there are a number of significant differences between the features of the "Easi-
Stand" and the invention described in Patent Specification, as follows:
(1) The length of the "Easi-Stand" lifting arm, 580mm, is significantly greater than the range of measurements of femur lengths previously mentioned and exceeds the upper limit (516.6mm) by 64.4mm, a measurement in excess of the expected accuracy of the parallelogram.
(2) The pivot point of the lifting arm is substantially offset from the vertical plane described by the axis of the ankle joint and the axis of the knee joint.
(3) The "Easi-Stand" embodies a sling which is of significant length when compared to the lengths of the other components of its lifting mechanism. This sling plays an important part in the lifting motion by either (i) comprising part of one side of a four sided lifting mechanism, by providing the lifting arm component of the lifting mechanism as a flexible element, articulated at the point of attachment of the sling; or by (ii) introducing a fifth element to the lifting mechanism, being the sling, located between the lifting arm and the patient’s upper torso.
(4) Each of the elements, or sides, of the lifting mechanism of the "Easi-Stand" are of substantially unequal length, and are not parallel.
(5) Whilst the Patent Specification does not provide a specific definition of the sling to be employed in the invention, the Specification identifies a number of characteristics of the sling, including its nature, its general provision and the ability to adjust its length to achieve a parallelogram, given that the lifting arm may be of fixed length. However, the Specification indicates that the sling should provide for attachment to the lifting arm with the attachment points located as close to the patient’s body as possible, consistently with the body being maintained in an upright position as the centre of mass falls below the lifting point.
(6) The Patent Specification indicates that the knee abutment means is optional, and is provided for positioning only and is not required to provide a reactive force during the lifting phase. However, the knee abutment means on the "Easi-Stand" is a necessary active element in the lifting mechanism, and is required to provide a reactive force opposing the lateral (i.e. posterior/anterior) force imparted by
the lifting arm as it is raised and the sling tension is applied to the upper torso.In Mr Scull’s opinion, each of these differences is very significant in relation to the working of the "Easi-Stand", in that they result in a substantially altered lifting mechanism when compared with that described in the Patent Specification, since: (1) the "Easi-Stand" does not embody a parallelogram lifting mechanism of the kind described in the Specification; and (2) the lifting action of the "Easi-Stand" creates a substantial lateral force on the patient’s knees.
In his view, the features of the "Easi-Stand" are not within any of the claims of the Patent Specification.
THE EVIDENCE OF IMPRO AND ARJO IN THEIR CASE IN REPLY
Affidavit evidence from Mr Rigby and Dr Stark was relied on by Impro and Arjo in their case in reply.
(a) The evidence of Mr R.A. Rigby
In his affidavit sworn on 8 December 1995, Mr Rigby joined issue with the opinion expressed by Professor Svensson that the location of the pivot point of the lifting arm as being disposed directly above the heel
position of the patient is “an important feature” of the Patent. In Mr Rigby’s opinion, the Patent does not, at least in claims 6 and 11, teach that this is an essential feature, since the position of the pivot point is only mentioned in claims 1 and 7 and in the corresponding description in the Specification concerning one aspect of the invention; and the two descriptions of hoists contained in the Specification and claims 6 and 11 are silent on the position of the pivot point.
Mr Rigby accepts that one of the significant features of the invention described in the Specification is the approximate parallelogram mechanism. The fact that the patient’s knees and feet are “substantially displaced laterally from a point directly below the pivot point of the lifting arm”, as in the case of the "Easi-Stand" hoist, does not, in Mr Rigby’s view, necessarily mean that an imaginary line joining that pivot point and the patient’s knees cannot be “more or less” or “approximately” parallel to an imaginary line joining the sling attachment points and the patient’s hips.
Referring to Profession Svensson’s description of one of the axes of the parallelogram mechanism as “the sling attachment point/patient’s armpits”, Mr Rigby could find no reference in the Patent Specification to the patient’s armpits as an axis.
With reference to Professor Svensson’s opinion that the object of the Patent’s parallelogram mechanism is to “ensure that the lifting force of the hoist is directed vertically, and passes through the centre of gravity of the patient’s torso, head and upper extremities....”, Mr Rigby could find no reference to this in the Specification since the lifting points of the mechanism, according to all aspects of the invention, follow an arcuate path. In Mr Rigby’s opinion, this describes a combined upward and forward movement, not a vertically directed force. Moreover, he says that, according to one aspect of the invention, “the hoist can be wheeled to a seated patient... [can] transport the patient to a different location, for example to a toilet or from a bed to a chair.” This suggests to Mr Rigby a lifting mechanism which, using variable sling lengths, can lift a patient, from many positions, reclined or slumped, where more often than not the line of force would be laterally angled, not vertical. According to Mr Rigby, the lifting mechanism has nothing to do with the centre of gravity of the patient. In his opinion, the only force exerted on the patient by the lifting arm is the force that acts through the sling which, according to Figures 1 and 6 of the Specification, does not act vertically.
Mr Rigby does not, as an interpretation of the Specification, accept the view expressed by Professor Svensson that the proper operation of the invention’s parallelogram’s motion requires that the patient’s torso be as vertical as possible, achieved through the use of the shortest possible sling, so that the patient’s torso is kept as close as possible to the sling attachment points.
In Mr Rigby’s opinion, using a short sling will not necessarily mean that the body of the patient is kept vertical. The position of the body will depend upon a number of factors including the position of the patient and the position of the sling around the patient at the beginning of the lift, which would be affected by such factors as the inclination of the chair on which the patient is seated and the position of the chair relative to the hoist.
Mr Rigby is of the view that the Specification teaches that the hoist and method are intended to be suitable when patients are other than vertically disposed during the lifting operation. Figure 6 shows, in his opinion, that the patient’s body is not vertical during the lifting process and the Specification speaks, in this context, of the patient being in a “slightly backwardly inclined position”. In his view, it is possible to achieve a parallelogram lift with any length of sling, provided that
the lifting column (an “upstanding support structure”) is of an appropriate height. If a long lifting column is used, a correspondingly long sling must be used.
Referring to the opinion evidence of Dr Cheng, Professor Svensson and Mr Scull in this context, Mr Rigby is of the view that there is nothing in the Specification which suggest that the opposite sides of the notional parallelogram must be equal in length or at all times remain parallel, since the Specification refers to “a more-or-less parallelogram motion” and “an approximately parallelogram movement”.
Referring to the view expressed by Professor Svensson that a requirement for the proper operation of the parallelogram motion is that “the arms [of the patient] are raised to a more or less horizontal position, in order to bring the patient’s centre of gravity forward of a line joining the hip and shoulder joints”, Mr Rigby could find no reference to such a requirement in the Specification. In Mr Rigby’s opinion, the invention can work where the patient has not sufficient strength in the arms to grip the hands of the hoist and the arms will then remain by the patient’s sides.
Mr Rigby is of the opinion that the “proper operation” of the “parallelogram motion” described by Professor
Svensson could be considered an “ideal” or “theoretical” operation of the lifting movement which would achieve an exact parallelogram movement, with the notional parallelogram having vertical sides, in which event there may be very little horizontal force exerted on the patient’s knees. In his view, bearing in mind the number of variables involved in lifting a patient including the position of the sling under the arms, the degree of muscular control of the patient, the way the patient is sitting (including the angles of the torso and thighs), the height of the chair and the length of the sling, it would only be in “very rare” circumstances that this “ideal” situation could be achieved.
Mr Rigby does not interpret the statement in the Specification “lifting is performed with no horizontal force tending to displace the knees” as teaching that there is no horizontal force whatsoever: the use of the phrase “knee abutment means” indicates to him that some horizontal force will be exerted; and Figure 6 envisages that, for severely disabled persons, the knee region would engage the abutment means at all times, and in the final standing position the patient will be slightly backwardly inclined.
Observing the "Easi-Stand" hoist in operation, Mr Rigby is of the view that the only two horizontal forces are those provided by the knee abutment and the sling;
and, according to the scientific laws, these two forces must balance, i.e. must be equal and opposite. In his opinion, the horizontal force exerted by the sling is T cos q, where T is the tension in the sling and q is the angle which the sling makes with the horizontal. Given that some horizontal force on the knees must be exerted in most cases, the words “the lifting is performed with no horizontal force tending to displace the knees” may, according to Mr Rigby, refer to the fact that there will be no negative horizontal force moving the knees away from the abutment means.
With respect to Professor Svensson’s view that the provision of a knee support is not to be regarded as important to the working of the Patent, Mr Rigby draws attention to the inclusion of a knee abutment means as an element of the hoist defined in claim 11.
On the question whether, as Professor Svensson and Mr Scull say, the sling, in the case of both the Patent and the "Easi-Stand", constitutes the introduction of a “fifth element” to the lifting mechanism, Mr Rigby notes that one of the various embodiments of the lifting hoist and the methods of lifting described in the Specification require the use of a sling; but he further notes that other than to say that the length of the sling may vary, the
Specification and the claims are silent on the nature of the sling.
In Mr Rigby’s opinion, the Specification teaches that the parallelogram movement there described is a “notional” parallelogram formed by four “imaginary” lines joining the corners of the parallelogram; and that although the Specification envisages a sling of varying lengths, it takes no account of the sling when the approximate parallelogram is described and the sling does not form part of the notional parallelogram. Moreover, Mr Rigby is of the view, previously noted, that a parallelogram lift, even a perfect one, can be achieved with any length of sling. In his view, both the lifting arrangements described in the Specification and exemplified in the "Easi-Stand" hoist include a sling which can be regarded as a fifth side, but this does not preclude the existence of a parallelogram as described in the Specification, because the parallelogram is “independent” of the sling.
By his affidavit sworn on 13 June 1996, Mr Rigby refers to the opinion of Dr Cheng that each of the integers of claim 1 is present in "Easi-Stand Mark II", except the following: (1) the “generally arcuate path” of the sling attachment points having an effective radius comparable to the length of the thigh bones of the patient; (2) the lateral horizontal axis of the arc being disposed
substantially directly above the heel position of the patient. With reference to the requirement in claims 1 to 6 that, during the lift, the sling attachment move along a “generally arcuate path”, Mr Rigby is of the opinion that the sling attachment points need not follow a precise arc of a circle in order to “mimic” the manual lifting technique of nurses. This, in his view, reinforces his interpretation of the phrase “comparable to the average length of [a] human thigh bone” in claim 6, and of the phrases “comparable to the length of the thigh bones of the patient” in claim 1, since the effective radius of the arc “need merely be of the same order” as the length of the thigh bone: the length of the thigh bone will vary from patient to patient and, in his view, these phrases therefore cannot mean anything approaching exact correspondence, since the Patent contemplates that most patients can be accommodated by the same hoist, but with a variable sling length.
Mr Rigby is also of the view that the use of the word “substantially” in the phrase “substantially directly above the heel position of the patient...” in claim 1, teaches that the lateral horizontal axis need not be directly above the heel position.
Mr Rigby also refers to Dr Cheng’s opinion that each element of claims 6 and 11 is present in "Easi-Stand Mark
II" with two exceptions: (1) the disposition of the attachment points at a radius comparable to the average length of the human thigh bone form the pivot; and (2) a lifting mechanism operative to raise the patient to a standing position. In Mr Rigby’s opinion, the invention described in the Patent is a lifting hoist to aid toileting of invalids, and the Specification describes the hoist as raising the patient “to a generally standing position”, and few of the patients would have the ability to stand upright. In his view, the use of the phrase “standing position” in claims 6 and 11 indicate a position which enables the patient to be toiletted and does not mean a completely upright position.
(b) The evidence of Dr H.L. Stark
In his affidavit sworn on 13 June 1996, Dr Stark expresses the opinion that the words “standing position” used in claims 6 and 11 are not meant to indicate that the patient must be upright on his or her feet, with the centre of gravity directly above the feet and the body weight supported by the feet. In his view, given the object of the invention, these words suggest a “generally” or “substantially” standing position; and the final position of the patient would depend to a large extent on the length of the sling and the height of the patient.
In Dr Stark’s opinion, claim 1 does not require the lateral horizontal axis to be positioned precisely above the patient’s heel position: the words used are “generally arcuate path” and “effective radius”; and claim 1 does not actually specify a lifting arm - no particular mechanism is required, and all that matters is the movement of the sling attachment points. In his view, it would be pointless to require that the attachment points follow a precise arc of a circle; and in terms of “practical reality”, it is sufficient to move the attachment points up and forward in a reasonably smooth fashion approximating an arc; nor would nurses using a manual technique lift in a geometrically perfect arc.
In Dr Stark’s opinion, the axis of the lifting arm need not be exactly above the patient’s heels, hence the use of the words “substantially directly above” in claim 1; and precise positioning is not critical when dealing with variable and flexible human beings. In his view, even on a strict geometric approach, the axis of the “ideal” arc ought to be displaced in front of the vertical plane containing the heels and knee joints, so as to allow for the thickness of the sling and its positioning on the body. His interpretation of Figure 1 is that the pivot point for the lifting arm cannot be vertically above the patient’s heels and knee joints, but is forward of that position, because of the thickness of the knee pad and the position
of the knee joint within the knee itself; this compensates to some extent for the fact that the sling passes around the front of the shoulders, so that the patient is “suspended” at a point forward of the spine; and the wider the band of the sling, the further forward the axis should be.
Dr Stark is of the opinion that the use of the term “effective radius” is again consistent with requiring only a path of movement which approximates to the “ideal” arc, so the path may not have a precisely defined radius; from a practical point of view, the starting and ending points are the most important; and if the path between them were flatter, or more curved, than the “ideal” arc, it would merely mean that the angle of the patient’s spine would vary during lifting. In his view, if the lifting arm is longer, then provided the pivot point is moved forwards or backwards to compensate, then the approximate desired arcuate movement can be achieved.
Dr Stark notes the statement in the Specification (p.5) that - “Preferably, the footplate... is ...fixed in a position relative to the support structure and the lifting arm is pivotally mounted on the support structure for movement about a fixed horizontal axis”; he further notes that claim 7 adds further features to claim 6, viz. (1) the lifting arm is mounted on the support structure for
“solely pivotal movement” and (2) the horizontal axis about which the lifting arm arrangement is pivoted is “disposed substantially directly above the footplate or footrests”. In his view, this indicates that the Patent contemplated that claim 6 would include rather more complicated arrangements than those shown in the specific embodiments of Figures 3 to 5.
With respect to Dr Cheng’s opinion on the point, Dr Stark does not accept that the words “disposed at a radius comparable to the average length of a human thigh bone...” are limited to a simple pivoted arm mounted on the support column. This is consistent with the description “generally arcuate path”; and if claim 6 were concerned purely with a simple pivoted arm, the attachment points would necessarily move through an exact arc; accordingly, the words “comparable to the average length of a human thigh bone” do not appear to have been intended to have any strict meaning.
Dr Stark believes that the language of the claims, as well as of the Specification, indicates that the Patent was deliberately seeking not to limit this invention to any particular mechanical contrivance for moving the lifting arm arrangement. The words “comparable to” are not very apt if there is a strict limitation on the length of the lifting arm; and the essential requirement is the ultimate
movement of the sling attachment points, which must approximate to the “arcuate” movement. But, in his view, neither the language of the claim, nor that of the Specification, indicates a strict limitation on the distance between the sling attachment points and a horizontal axis about which the lifting arm arrangement is pivoted.
THE EVIDENCE OF NESBIT IN ITS CASE IN REPLY
Nesbit relied, in its case in reply, on affidavit evidence from Professor Svensson, Mr Scull, Dr Ackland and Dr Cheng.
(a) The evidence of Professor N.L. Svensson
In his affidavit sworn on 14 February 1996, Professor Svensson expresses his opinion (1) that the invention involves a parallelogram mechanism used to assist the raising of a patient from a seated, to a standing position, the patient perhaps being so disabled as to provide no assistance in the lifting process, all of this being in accordance with the known laws of mechanics; (2) that the parallelogram mechanism comprises (a) the lifting arm; (b) the thigh; (c) the trunk; and (d) the support column (from knee joint to lifting arm pivot); (3) that lifting occurs without any horizontal force being applied to the
knees and without muscular effort at the knee and hip to provide movements at the knee and hip joints.
In his opinion, the laws of mechanics inevitably lead to the conclusions that the lifting force must be vertical and the centre of gravity of the (sling supported) upper part of the body lies vertically below the point of attachment of the sling.
Professor Svensson accepts that, in the case of the "Easi-Stand", the lines joining the pivot point and the knees, on the one hand, and joining the sling attachment points and the hips, on the other, may be “more or less” parallel at some time during the lifting process, but is of the opinion that they will not be so at all times.
The Macquarie definition of the adjective “average” is similar, including:
"6. Of or pertaining to an average; estimated by average; forming an average. 7. Intermediate, medial or typical in amount, rate, quality etc."
Its definitions of the noun include:
"1. An arithmetical mean. 2. A quantity intermediate to a set of quantities. 3. The ordinary, normal or typical amount, rate, quality, kind etc.; the common run..."
The Macquarie defines the noun “arithmetic mean” as:
"Maths.The mean obtained by adding several quantities together and dividing the sum by the number of quantities. For example, the arithmetic mean of 1, 5, 2, 8 is 4."
It follows that it may be said that, ordinarily, there are three possible meanings of the term “average”: (1) the arithmetical mean; (2) a medial estimate; or (3) the ruling or typical case or the common run.
In my view, it is highly unlikely that, in the present context, the precise mathematical calculation of the kind required by (1) was intended here. It is also not likely that, in this connection, (2), that is, the exercise being the ascertainment of the intermediate quantity, could have been thought to be feasible, given the volume of the data to be collected and analysed, even if due allowance be made for the potential application of the “team” concept discussed in Tetra Molectric Limited v. Japan Imports Limited (1976) RPC 541 at 583.
On the other hand, in my opinion, there is much to be said for the application of the third meaning in the present context, that is, the typical length of a human thigh bone. This would call for a “by and large”, rather than a mathematical, approach. A “by and large” approach
would fit easily with the notion of “comparable” that I favour here, that is, capable of being represented as similar or analogous, or likened, to another thing. I propose to adopt this third meaning of “average” in the interpretation of the Patent.
(b) Did Nesbit’s apparatus infringe?
It is common ground between the parties that the Patent is a combination patent and that, to establish infringement, the “Easi-Stand” Marks I and II must embody all of the essential features, or integers, of the patentee’s claims. However, the Court will avoid a too technical or narrow construction of the claims when assessing infringement of combination patents: See Populin v. HB Nominees Pty Ltd (1982) 41 ALR 471, per Bowen CJ, Deane and Ellicott JJ at 475. The fundamental issue to be resolved on a question of infringement is “whether the substantial idea disclosed by the Specification and made the subject of a definite claim has been taken and embodied in the infringing thing.”: Radiation v. Galliers and Klaerr Pty Ltd (1938) 60 CLR 36 per Dixon J. (as he then was) at 51.
On behalf of Nesbit, it is submitted that its units differ, as a matter of substance, from the essential features of the invention in several respects. It will
be convenient to consider these submissions in turn, whilst recognising that Impro and Arjo, of course, bear the onus of proving infringement:(1)It is first submitted for Nesbit that, in the lifting action, neither of its units utilises a parallelogram, or even an approximate parallelogram, which action is required to be present, the argument runs, in order for there to be no force, or no substantial horizontal force tending to displace the knees of the patient.
I have difficulty accepting the submission.
In the first place, I have already rejected Nesbit’s precise geometric approach to the interpretation of the Patent, favouring instead a more practical, “by and large” approach to conclude, as I do, that merely an approximation of a parallelogram is intended, with a view, in my opinion, to emphasising the essential feature of the Patent that there is a requirement of a sympathetic motion between the lifting arm and the patient’s thighs.
Secondly, in my opinion, it is clear that the lifting action of the invention on the one hand and
Nesbit’s apparatus on the other, may each be characterised, on observation, as an approximate, or “more-or-less” parallelogram movement in the sense previously discussed. It is not to the point, for the reasons already given, that there is no precise or geometric parallelogram here.
Thirdly, Nesbit’s argument proceeds on the assumption that a perfect parallelogram will result in no horizontal force at the knees, but this assumption is not valid, unless it be further assumed, as was discussed in the expert evidence, that the pivot of the lifting arm and the patient’s knees and heels are all in the same vertical plane. That is to say, as soon as the pivot point is moved away from the patient, then, even if the relevant radius and the patient’s thighs are both equal in length and perfectly parallel, the lift will, in my view, produce a resultant horizontal force at the knees; and although claims 1 to 5 may be differently framed in this respect, claims 6 and 11 are silent on the location of the pivot point. Moreover, as has been said, the provision for knee abutment means in the invention recognises that, in some at least of its embodiments, there will be a resultant force at the knees. Further, in considering the complex of forces, the angle of the sling to its attachment should also be taken into account since it will provide a horizontal component to the lifting force which will be resultant to the knees.
(2)It is secondly submitted for Nesbit that the pivot of the lifting arm arrangement in its apparatus is not disposed substantially directly above the heel position of the patient with the latter facing the subject axis, which arrangement, the submission goes, is necessary to be present so as to enable the parallelogram or approximate parallelogram to exist, and thereby result in there being no or no substantial horizontal force tending to displace the knees.
I have already considered this contention in (1) above. For those reasons, I cannot accept the argument.
(3)Next it is submitted for Nesbit that the lifting process of its units does not result, as the Specification requires, in the attachment points on the lifting arms for the sling moving upwardly or along “a generally arcuate path” wherein the arc has an effective “radius comparable to the average length of a human thigh bone”.
In the construction of the Patent in this respect, the notion of, or exercise in, “comparability” required by the Specification is not, in my view, an abstract one where the addressee of the Patent is merely called upon to ascertain whether or not the length of the relevant radius falls within a notional range of measurement. Rather, as counsel for Impro and Arjo submitted, a common sense approach to construction should be adopted which has regard to the facts that what is claimed to be a feature is a radius identified by reference to a lifting hoist designed to lift a patient from a seated to a substantially standing position by means of a sling attachment to a lifting arm arrangement; and that, in the operation of the invention, as the lifting arm pivots and moves from a rather horizontal disposition to a more vertical one, so also the patient’s thighs pivot at the knee and at the hip, and also move from a rather horizontal disposition to a more vertical one, and at all times the thighs move in co-operation, or in sympathy with, the lifting arm. Further, as was submitted by counsel for Impro and Arjo, in this connection, the issue of “comparability”, which necessarily involves an element of judgment, is to
be tested by reference to this functional characteristic.
It follows that I cannot accept the approach to construction of the Patent adopted by Nesbit’s experts to the effect that “comparable” here means “equivalent” or “as close as possible to equivalent” or the same length “within certain tolerances”. Rather, as I have held, the Patent should be construed so as to refer to a length similar to the typical length of a thigh bone; and, in my view, in the case of each of the “Easi-Stand” hoists, the radius of the arc through which the attachment points of the lifting arm move, calculated by reference to the imaginary line drawn between the pivot point of the lifting arm and the attachment points, is “comparable” (in the above sense) to “the average” (in the above sense) length of a human thigh bone.
The difficulties encountered upon an application of the strict approach to construction suggested by Nesbit’s expert evidence were illustrated by counsel for Impro and Arjo in the following examples of the consequences of and attempt to assign to the length of the relevant radius a precise range of measurements based on
anthropometric data not referred to in the claims or the body of the Specification.
As has been noted, Mr Scull, in his affidavit sworn on 21 September 1995, adopted the Dreyfus data, choosing, as an upper limit of the range, a measurement of 515.6mm. However, Dr Ackland, in his affidavit sworn on 13 June 1995, relied on the Pheasant data, indicating an upper range of 525mm. Yet Mr Scull accepted that, although clearly not “equivalent”, there was no reason why the Dreyfus data should be preferred. (Transcript p.292).
Moreover, if the upper limit of the Pheasant data for the 95th percentile is taken (i.e. a notional thigh length of 525mm) and if the tolerances suggested by Mr Scull in his evidence (see below) are applied, then the difference between the radius of the Mark I version of the “Easi-Stand” is only 3.5mm. It is difficult to accept that this should not be regarded as a “comparable” length. It is true that the length of the Mark II is greater. Here the comparison is between a radius of 650mm with a thigh length of (say) 525mm. If, as Mr Scull suggests in his affidavit sworn on 21 September 1995 there is an allowable tolerance of 51.5mm, a difference of 73.5mm results. As has been noted, Dr Ackland said (Transcript p.329) that the length of the radius of 580mm was “certainly close” to the measurement of 525mm; and, in the context of the lengths of the sling, Professor Svensson described a difference of about 50mm as “only small”. (Transcript p.147).
In my view, the strict approach suggested by Nesbit’s expert evidence depends to a significant extent upon a range of lengths upon which the Specification is silent, and no convincing reason for their importation into the Specification has been made out. Taking a practical and purposive approach to ascertain the meaning of the Patent, I cannot accept this strict approach, which can lead to fine and artificial, and in some cases, arbitrary, distinctions being drawn. Given that this is a lifting rather than a measuring, invention, the strict approach advocated by Nesbit is, I think, inconsistent with the whole tenor of the Patent.
Finally, it should be noted in this connection that Nesbit did not lead any evidence to explain why, if there is a significant reason, there is a difference between the lengths of the lifting arms of the two versions of its apparatus. As has been
seen, Nesbit’s evidence accepts that there is no significant difference in function between the two, or between its apparatus and the invention. There is nothing in Nesbit’s evidence to suggest that the “Easi-Stand” hoists provide any advantage or improvement vis-à-vis the invention.
(4)It is next contended for Nesbit that, as a result of the positioning of the pivot point of the lifting arm of its apparatus deviating substantially from the same vertical place as the patient’s heels, the lifting actin of its apparatus results in there being substantial horizontal force tending to displace the knees.
For the reasons given in (1) above, I cannot accept that any substantial difference between the "Easi-Stand" and the invention is indicated here. The circumstance that the "Easi-Stand" usually requires knee abutment does not signify any substantial difference in function, which remains that of raising invalid patients from a seated to a basically standing position.
(5)Finally, it is submitted on behalf of Nesbit that the knee abutment means on its apparatus are not, as is the case in the invention, for the specific
purpose of “locating” the knees upon initial engagement and thereafter for the knees to “remain at rest against the knee abutment means” without being subjected to any, or any substantial horizontal force tending to displace them; but rather for the specific purpose of being subjected to, and restraining, the substantial force which is generated by the knees.For the reasons given in (1) and (4) above, I cannot accept this submission.
____________________
It follows that Impro and Arjo have established to my satisfaction that both versions of Nesbit’s hoists infringe the Patent.
I turn next to the cross-claim for revocation.
NESBIT’S CROSS-CLAIM FOR REVOCATION
It will be convenient to consider the grounds relied on by Nesbit in turn.
(a)Fair basing
Nesbit’s argument here was put in several ways.
First, it was submitted for Nesbit that it is an essential feature of the invention that there be a parallelogram lift substantially throughout the lifting procedure; but, according to some at least of their expert evidence, Impro and Arjo contend that the claims of the Patent include any quadrilateral or pentagonal lift, and are not confined to what can properly be described as substantially a parallelogram lift; and if such construction be correct, the claims are not fairly based on the invention discussed in the complete Specification.
Nesbit’s point is really one of construction. Having regard to my construction of the claims, I cannot accept Nesbit’s submission. I have found that there is implicit in the claims a requirement that there be only an “approximate” or “more-or-less” parallelogram; and that this is also the requirement, properly construed, described in the body of the Specification. It follows, in my view, that there is no inconsistency between the claims and the description of the invention in the body of the Specification, upon the true interpretation of the whole Patent.
It was then submitted for Nesbit that, with reference to Dr Stark’s evidence in paragraph 10 of his affidavit sworn on 7 December 1995 to the effect that a length several times that of the patient’s thigh bone could be regarded as “comparable”, that if such a construction be correct, then there is a lack of fair basing.
Again, the question is essentially one of the construction of the claims and of the body of the Specification. Since, as has been seen, no inconsistency arises on my construction of both, I cannot accept Nesbit’s submission.
It was next submitted for Nesbit that Impro and Arjo contend that the invention does not include, as an essential integer or feature, a requirement that the lifting be performed “with no horizontal force tending to displace the knees”; and that if such a construction be correct, the claims are not fairly based.
Once more, according to my construction, no such inconsistency arises. As has been said, on my interpretation of both the claims and the description of the invention in the body of the Specification, whilst it
is preferable, if possible, that there be no such force, in some situations that force will occur.
(b) Ambiguity
Nesbit contends that each of the following phrases in the claims is ambiguous:
"“radius comparable to the average length of the human thigh bone”: Claim 6(ii)(f);
“substantially directly above the footplate or footrests”: Claim 7(ii);
“knee abutment means for location of the knees of the patient”: Claim 10;
“knee location abutment means”: Claim 11 (iii);
“knees of the (patient) located against the said abutment means”: Claim 11(v)(b);
“effective radius comparable to the average length of a human thigh bone”: Claim 11(ii)(f);
“with the feet... supporting a substantial part of the total body weight of the patient... while also supported in the standing position by the sling”: Claim 6(9v)(d)."
In Minnesota Mining and Manufacturing Company v. Beiersdorf (Australia) Limited (1980) 144 CLR. 253, Aickin J. (Barwick C.J., Stephen, Mason and Wilson JJ. concurring) said (at 274):
"The standard is laid down as being “inextensible” when subjected to “ordinary hand pulling” in its use as a surgical tape, the backing of which is a thin nonwoven resilient
textile material, and in such circumstances it is to be, as the body of the specification says: ‘relatively inextensible’ or ‘not capable of stretching appreciably’.
This is no doubt a simple and pragmatic criterion but one likely to be readily understood by those who use surgical tape, or who would, after expiration of the patent, wish to manufacture it. Lack of precise definition in claims is not fatal to their validity so long as they provide a workable standard suitable to the intended use - see British Thomson-Houston Co. Ltd. v. Corona Lamp Works Ltd. ... and Monsanto Co. v. Commissioner of Patents... ."
In my view, the above phrases also provide simple and pragmatic criteria which are likely to be readily understood by the skilled addressee. It is true that their proper meaning was extensively debated in the expert evidence, as has been seen, and in final addresses, but it does not follow that a reference to a relative expression calling for the exercise of judgment involves the imposition of an unworkable standard. I cannot accept that this ground of objection has any real force.
(c) Inutility
On behalf of Nesbit it is contended that, although the claims may be construed so as to extend to patients without the capacity to bear weight on their feet, for instance, a quadriplegic or a person whose legs have been amputated; yet, the submission runs, the invention
requires that the patient’s feet have the capacity to support 40% or so of the patient’s body weight during the lift. It follows, Nesbit says, that the invention lacks practical utility.I have difficulty accepting the contention. It is plain from the Specification and the claims that the object of the invention is that the patient will be raised to a “generally standing position”. Implicit, if not explicit, in this statement is the recognition that, generally, the patient can take some of the weight through his or her legs, so that although as earlier discussed there may be questions of degree involved, the claims either expressly or by necessary implication are limited to this extent; the should accordingly be read down to the use of the invention where the patient, with the assistance of the hoists, is generally able to stand (see International Business Machines Corporation v. Smith (1991) 105 ALR 388 per Burchett J. at 392; Atlantis Corp. Pty. Limited v. Schindler (1995) 33 IPR. 91 per McLelland C.J. in Eq. at 979-8). It should also be noted that, as Gummow J. said in Rescare Ltd. v. Anaesthetic Supplies Pty. Ltd. (1992) 25 IPR. 119 (at 142):
"... a claim may have utility even though the promised advantage is not achieved in all cases."
Next, Nesbit submits that the invention cannot work unless the lifting arm is adjustable.
I have difficulty accepting this argument. It is true, as has been noted, that there was much discussion in the expert evidence as to the possibility of there being a discrepancy between the radius of the lifting arm and the “average” length of a human thigh bone. But there appears to be no suggestion in the evidence that the existence of any such discrepancy (whether great or small) has the consequence that the invention cannot work, that is, unless the lifting arm can be adjusted to a length “comparable” to the “average” length of a human thigh bone. It is difficult to conceive of a situation of inutility where the discrepancy is small. Beyond that, given the context of the “by and large” parameters previously discussed in considering the notions of “comparability” and “average”, the issue really becomes one of degree, for which specific evidence would be needed to justify a finding of inutility. In the absence of such evidence, that finding cannot be made.
Nesbit also contends that there is inutility because the Patent cannot be performed with no, or no substantial, horizontal force tending to displace the knees.
This aspect has, of course, been considered at some length in the context of other differences or grounds of revocation relied on by Nesbit. As I have construed the Patent, it is contemplated that, preferably or ideally, there will be no such force, but it is also contemplated that it is possible that in certain practical situations, previously mentioned, such a force may be generated. On that construction, and on the evidence before me, no finding of inutility on this suggested ground is warranted.
(d) False suggestion and misrepresentation
It is contended for Nesbit that there is a promise in the Patent that the invention can be worked with no, or no substantial horizontal force tending to displace the knees; and that, in the circumstances, the promise is illusory.
Again, on my construction of the Patent, both an “ideal” or “preferred” embodiment as well as a more “practical” embodiment are contemplated, depending upon the strength of the legs of the individual patient.
It will be recalled that the following is stated in the body of the Specification (at pp.9-10):
"The full operative movement of the lever... raises the lifting arm arrangement... through an angle of 160o during which the patient... is raised to a standing position on the footrests... comfortably supported, in a somewhat backwardly inclined and secure position, by the sling.... In this position infirm and seriously disabled patients will be supported with the knees still in engagement with the knee pad..., but patients with sufficient muscular tone will involuntarily straighten the knees and thus be supported with the body completely straight."
It will further be remembered that the following is also stated in the body of the Specification (at pp.16-17):
"The lifting of an infirm or severely disabled person is illustrated in full lines in Figure 6, as shown the knee region engaging the abutment means KA at all times even when in the final standing, and slightly backwardly-inclined, position. However, patients with sufficient muscular strength will involuntarily straighten their legs during lifting so that, in the final position the body is completely straight between the footrests or footplate F and the sling S. Thus for these patients the abutment means KA merely provide location at the initial stage of the lift."
As has been seen, each of Nesbit’s experts accepted in their evidence that the Patent teaches that there may be some force at the knees in the course of working the invention.
In my opinion, this ground of revocation has not been made out.
(e) Obviousness
It will be recalled that in his affidavit sworn on 14 February 1996, Professor Svensson expressed the opinion that in 1983 a skilled addressee “would have considered the use of a parallelogram mechanism to be an obvious solution to the problem [of overcoming the disadvantages encountered with hoists at that time]”.
In his submission, Senior Counsel for Nesbit invited the Court (Transcript p.440) to interpret this evidence as the expression of the opinion that “a parallelogram linkage was well known as a particular type of four-bar linkage [so that the supposed] inventive step [was] obvious”. Although it may be accepted that an “approximate” or “more-or-less” parallelogram is implicit in the claims, this is only one of its features. As has been noted, this is a combination patent which embraces several features, including something which approximates a parallelogram. In short, there is more to the invention than the application of a four-bar linkage system.
Moreover, as counsel for Impro and Arjo pointed out in argument, the only evidence before the Court concerning the prior art was that given by Ms Brown, who, as has been seen, described the “Stella” hoist, one of
the embodiments of the Patent, as “quite unique” in 1985; no attempt was made by Nesbit to prove what was common general knowledge at the priority date; and the opinion of Professor Svensson (along with similarly brief evidence from Mr Scull) really rested in no more than assertion and was not sought to be supported by any factual foundation or by any substantial process of reasoning.In my opinion, this ground of objection is not made out.
(f) Sufficiency
On behalf of Nesbit, complaint is made that the Patent failed to specify the relevant anthropometric data as to the “average length of a human thigh bone”. But, as I have interpreted the Specification, the invention is not defined by reference to any such data in the precise sense sought to be suggested by Nesbit’s expert evidence.
In my view, this ground of objection has not been established.
In the result, the cross-claim must be dismissed.
ORDERS
I make the following orders at this stage:
Direct the applicants to bring in draft short minutes of the order to be made in accordance with the reasons for judgment.
Reserve costs.
I certify that this and the preceding one hundred and sixty four (164) pages are a true copy of the Reasons for Judgment herein of his Honour Justice Beaumont.
Associate:
Dated: 23 December 1996
Counsel and Solicitors D M Yates with J Goddard instructed
for Applicant: by Sprusons
Counsel and Solicitors J J Garnsey QC with P McCormack
instructed by Deacons Graham & James
for Respondent:
Date of hearing: 4, 5, 6, 7, 8, 12, 13 November 1996
Date Judgment delivered: 23 December 1996
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