England and Wales High Court (Patents Court) Decisions

B E T W E E N

- and -

Defendant

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B E T W E E N

- and -

Defendant

1. Hearing dates: 9 & 10 December, 1997

2. Judgment Date: 10th December 1997

DATED: 10/12/97

3. Corrected from Transcript: 27/2/98

1. This is an action for infringement of a patent number 0 007 699 which relates to devices for stripping the plastic coating from electric cables. The device illustrated in the patent looks rather like a pair of scissors. However there are two sets of jaws, one nested within the other. On squeezing the handles together, the two sets of jaws clamp on a piece of wire located between them. When the outer jaws have firmly gripped the piece of wire, the inner jaws, which also have gripped the wire and will have cut into the plastic sheathing around it, move away from the outer jaws in an axial direction, so as to strip the plastic coating from the wire. This relative movement in an axial direction between the inner and outer jaws involves the use of a lost motion device, various cams and cam followers to which I will refer hereafter. The resulting device is extremely effective rendering wire stripping easy. Within fairly wide limits it self-compensates for different thicknesses of wire.

2. As the expert witnesses agreed, the way in which the patented device works is quite complex. However, before dealing with the details of construction and operation, it is necessary to put this device in its proper context. As the patent in suit makes clear, the use of wire strippers having two sets of jaws, one nested within the other, the inner set being cutting and stripping jaws, and in which a lost motion device is used for moving the inner jaws axially relative to the outer jaws, is known. There are a number of prior art patents which teach how to make and operate just such devices. These are described in general terms in columns 1 and 2 of the patent and certain claimed disadvantages of those prior art devices are set out.

3. Against that background, the patentee, at column 2, line 22, says:

4. It is important to have this context in mind when construing this patent and in particular its claims, because what the patentee is not entitled to seek a monopoly for is any device which, by use of two pairs of jaws and relative movement between the inner and the outer set of jaws, can achieve stripping of a plastic coating from a wire. The patentee did not suggest otherwise. What he claims to have done is develop a particular type of mechanical arrangement which achieves what other devices have achieved in the past, but perhaps more simply, more reliably, or more flexibly.

5. With this in mind, I turn to consider the precise mechanism described and illustrated in the patent in suit. For this purpose I will refer to figures 1 to 4 in the patent and the numbering on them. They have been partially coloured to assist in understanding them.

6. Fig 1 shows a device which has two handles which are indicated by the numerals 18 and 12. Lower handle 12 is connected to the upper outer jaw 10. The upper handle 18 is pivoted to the upper jaw around a pivot pin 20. The lower outer jaw is indicated by figure 14 and it is pivoted to the lower handle at a pivot point 16. Between the upper and lower handles there is a component indicated by numeral 50, which is called an actuator. It is illustrated in Fig 5. At the front end of the actuator there is a triangular slot in which a pin 32 is located, that pin being connected to the two inner jaws 30 and 28 (the latter jaws are shown particularly clearly in figure 4 where they are in a retracted position holding the plastic sheath of a piece of stripped wire). That slot is the lost motion part of the actuator. The actuator also has an open mouthed slot 58 in it towards its middle. The upper surface of that slot in the actuator is a cam surface, the operation of which I will describe in a moment. The actuator is connected indirectly to the upper handle 18 by means of an elongated strip of material indicated by numeral 54 in Fig 1. That component is pivoted at its top end to the upper handle and at its bottom end to the actuator. The bottom outer jaw 14 carries at its rearward extension a roller, 62, which fits in the open mouthed slot in the actuator. This roller functions as a cam follower, as I will explain in a moment.

7. As shown in Fig 1, the wire stripper is in its open, unused state. If a piece of wire is now introduced into the space between the jaws shown at the left-hand side of the figure, and the handles are squeezed together, the following happens. The movement of the handle 18 towards handle 12 will transmit a force along the component 54. That components is described in the specification as "a link". Thus, handle 18 pivots around its pivot point 20 and exerts a force along the link 54. As shown in Fig 1, that force will be in a direction of about five o'clock. That force can be resolved into components both vertically downwards and horizontally, to the right, as shown by the letters A and B in Fig 1.

8. The effect of this is as follows. First of all, the force in direction A (that is the downward force) will tend to push the actuator down on to the roller 62. That, therefore, is pushing on the right end of the component 14, which is pivoted about point 16. This causes the left end of that component, that is to say the left end of the bottom outer jaw, to move upwards towards the upper outer jaw 10. Furthermore, any movement in the direction B (i.e. to the right) will cause the roller to move on the cam surface 68 of the slot in the actuator (see Fig. 5). The actuator, therefore, will move to the right somewhat. Because this will cause the roller to move along the cam surface 68, it will also push that roller downwards thereby reinforcing the pivoting motion about 16. In fact, the actuator can only move to a limited extent in the direction A because it will come to a stop against another roller which is indicated at 70 on Fig 1. I should point out, and it was agreed by all parties, that Fig 1 is inaccurate in that it appears to show the actuator already at its final position, jammed against roller 70. If it were accurate it would show a little gap between 70 and the bottom face of the actuator.

9. In any event, when the actuator has reached the lowermost position it can adopt, all further force applied through link 54 must be translated into movement axially in the direction B. This has the result that the actuator now mainly moves in a rightward direction. The outer jaws 10 and 14 will be closed, as will the inner jaws 28 and 30. As the actuator moves to the right, the pin 32, in the lost motion part of the actuator, will come up against the forward wall of the slot and from that point onwards, further movement of the actuator to the right will cause the inner jaws 30 and 28 to move in a rightwards direction, that is in direction B. In fact, as the handles come together, the link 54 will adopt a position which gets ever closer to the horizontal. This can be seen, for example, by comparing Fig 1 to Fig 3. The result of this is likely to be that the component of the force transmitted along link 54, which is in the axial direction B, will increase as the handles come closer together, whereas the component in the vertical direction will reduce. Eventually, at the end of operation, when handles 18 and 12 are closest together, the cam follower roller 62 enters a part of the actuator slot where the cam causes the cam follower roller to move in an upward direction. This pivots the lower outer jaw 14 in an anticlockwise direction round the pivot 16 and opens the outer jaws.

10. As I have said, and as I think the parties and experts agreed, this is a neat, sophisticated and effective device for stripping the plastic from a piece of wire.

11. The defendant's product is made in accordance with its own patent which is to be found at Bundle 3, tab 11 of the trial documents. For the sake of this judgment, I will describe the operation of the defendant's device by reference to one of the drawings annexed to the latter patent. To avoid confusion, I have called it Fig. 6. It is as follows:

12. Insofar as the defendant's device can be likened to the plaintiffs' device, the disposition in Fig 6 is the other way up to the disposition of the device in Fig 1 of the plaintiffs' patent. The top handle 12 is connected to the lower outer jaw 11. The bottom handle 30 is pivoted around a pivot point 29 located on the upper part of the top handle 12. The upper outer jaw, that is to say the part equivalent to the lower outer jaw 14 on the plaintiffs' device, is pivoted about a point 13 and it has at its rearward end, a roller 43 which acts as a cam follower. The bottom handle component is in the shape of a leg. In its bottom left-hand corner, that is to say where the heel is, there is a pivot 33. To that pivot is attached, in a rotational manner, an actuator 36. The actuator has a cam surface 37 on which the roller 43 can travel. Furthermore, it has attached to its bottom surface one end of a spring 44 the other end of which is attached to the upper surface of the bottom leg. This spring urges the free end of the actuator into contact with the roller.

13. The defendant’s device operates as follows. As handle 30 is pulled towards handle 12, the actuator 36 is kept in contact with the roller 43 at the right-hand end of the component which carries the upper outer jaw. The result is that the operation of the lower handle pushes that roller 43 in an anticlockwise direction around its pivot point 33. This has the effect of urging the upper outer jaw down towards the lower outer jaw below. At the same time the downward movement of handle 12 causes the lower outer jaw to rotate in a clockwise direction towards the upper outer jaw. Once again, between the outer jaws there are inner jaws 17 and 18which are used for cutting and stripping. They are connected with a slider bar through a pivot point 19. The slider bar has at its rearward end a pin sticking out of it, which is indicated at 39.

14. Once the handles 12 and 30 have been operated sufficiently to bring the outer jaws together, so as to touch any wire put between them, further movement of the handles has the following effect. First of all, because the lower handle is pivoted at 29 on the upper handle component, its bottom leg and its heel will move in a generally rightwards direction. Since the heel carries on it the pivot point for the actuator, this will move the actuator towards the right. At the same time, the actuator will be rotated anticlockwise. However, when the upper component can move no further, because it has reached its maximum position of travel in an anticlockwise direction, further movement of the actuator to the right, caused by the leg-shaped configuration of the bottom handle component, will force the cam follower 43 to run on the cam surface 37, on the right-hand end of the actuator, thereby pushing the actuator in an anticlockwise direction. At the far left hand end of the actuator is an upstanding finger, having an internal circular surface. It is designed to catch the pin 39 on the slider for the internal jaws. As the left hand end of the actuator moves to the right, that pin will be contacted by the finger and will, itself, be pulled to the right. That rightward motion is accentuated by the fact that the finger will also be travelling in a clockwise direction because the actuator itself is now moving in a clockwise rotation as a result of the cam follower running on the cam surface 37. The result of this, once again, is to pull the inner jaws, 18 and 17, to the right, helping to strip off the plastic sheathing of the wire clamped firmly between them. Eventually, the cam follower 43 rides over a hump marked 38 on the actuator 36 and this results in the jaws opening up to release the wire.

15. The main issue with which I am faced here is one of infringement. Arguments of obviousness and insufficiency are also run, although only as a long stop in case the arguments of non-infringement advanced by the defendant failed. Claim 1 of the patent is in the following terms:

16. The patentee has stated in column 2 what he believes to be the essence of his invention in the following terms:

17. That floating cam is part of the internal surface of the actuator 50 illustrated in the figures to the patent specification. It can be seen that, subject to constraints placed upon it, for example by roller 70, and the the upper handle, the actuator itself can move generally in an up and down direction and in a left to right direction during operation, so that the cam associated with it can also move in a generally upward and downward direction and in a left to right direction. In that sense it can be said that the cam has the ability to float in the apparatus.

18. Perhaps the most important point on non-infringement, although by no means the only point, was as to the meaning of the word "link" in claim 1. It is clear from the wording of Claim 1 itself that what is being referred to as the "link" is the item 54 shown in the drawings. Item 54 is the elongated component with a pivot at either end. Mr. Miller QC, who appears on behalf of the defendant, and has argued its case with great economy, says that "a link" must be an elongated member with pivots at either end and what it certainly is not is a single pivot. It is not in dispute between the parties that if there is a link in the defendant's apparatus, it is constituted by the pivot point 33 around which the actuator can rotate.

19. The patent specification is directed to technical people, particularly those interested in the manufacture of wire stripping apparatus. The word "link" is perhaps one of those unfortunate words which can be seen as having somewhat different meanings in common usage and in the technical field. In particular, in common usage, the word "link" when used as a verb can mean, amongst other things, to connect or join things together. Therefore, it is possible to say that things are "linked" together when they are "joined" together. However, in technical parlance, "link" has a more precise meaning. The evidence given before me by Mr. Samuel Molian, an expert called on behalf of the defendants, was as follows:

20. In support of that view, various technical books were exhibited and in particular a Dictionary of Mechanical Engineering was relied on which defined "a link", at least so far as relevant for the purpose of this case, in the following words:

21. The defendant says that is what is shown in the patent in suit and that when the claim relates to "a link (54)", it means precisely the type of component referred to by Mr. Molian and in the dictionary quotation I have set out above.

22. In the end, I am not sure that there was really much dispute as to the meaning of the word "link" in a technical field such as this. The expert called on behalf of the plaintiff, Mr. Undin, is a very experienced technician. Although English is not his mother tongue, he is, to all intents and purposes, bilingual and he is put forward by the plaintiffs as being competent to discuss the use of technical words in the mechanical field in the English language. At the end, I do not think Mr. Miller disputed his ability to explain what technical words mean in this field in the English language.

23. What Mr. Undin said was this. He was asked in one part of his cross-examination whether he could think of any occasion where the word "link" is used otherwise than to denote a connecting piece which is pivoted, or at least constrained, at both ends. His answer was as follows:

24. His cross examination included the following:

25. The description in the Dictionary of Mechanical Engineering was then put to him and he was asked:

27. Mr. Miller, rightly in my view, did not need to take the matter further, by putting further dictionary definitions to Mr. Undin. In my view, it is clear that the word

"link" in claim 1 is used in its proper technical sense. It is the ability for there to be relative vertical and lateral movement between the actuator and the upper handle, which is one of the essential features, as I read it, of the patent in suit. That ability to move in both directions and, importantly, to transmitted forces in different ways in different parts of the operation of the cycle is dependent on the elongated link member 54, which is pivoted at both ends.

29. In my view, on a proper reading of claim 1 of this specification, the word "link" is used in its technical sense to denote an elongated component, pivoted at either end. Mr. Wyand QC, who appeared on behalf of the plaintiffs, draws my attention to claim 2 and says that there the word "link" is defined as being pivoted at its ends and that, therefore, this indicates that the word "link" in claim 1 must have a more general meaning which would encompass a simple pivot. I am not persuaded by this argument. What claim 2 is doing is indicating where the link is located, that is to say, to what other items in the hardware it is pivoted. It does not indicate that the word "link" has a less technical meaning in claim 1. It therefore follows that, on this point alone, there is no textual infringement of claim 1 of the patent in suit.

and 12 shown in Fig 6 above, come together, the outer jaws are closed, not by movement of the cam follower 43 along the cam 37, but by the fact that the motion of the lower handle 30 is transmitted directly to the cam follower 43 through the medium of the spring, which is indicated at 44 on the drawing. Indeed, as I understand it, this was not in dispute. The closing of the outer jaws and, in particular, the closing in the early stages is all achieved, not by the actuator and its cam at all; it is the handle 30 moving towards the handle 12, and the spring acting indirectly on the roller of the cam follower 43 which causes the outer jaws to close. Mr. Wyand said that even though that is true, once the outer jaws have closed, for example, onto a piece of wire, so that they can close no further, then at that point the cam follower 43 will be forced along the cam surface 37. That will compress the spring and add further rotational force, causing the upper jaw 14 to further compress on the lower law 17. In my view, that is not enough to come within the words of the claim. The link is for initially causing the actuator cam movement to close the jaws. The jaws are closed, it seems to me, not by that cam and certainly not in the initial phases. On this point also there is no textual infringement of the claim.

31. It also seems to me that the actual mode of operation of the defendant's item is rather different to that of the patented device. It is true that the actuator can move in a direction left and right as shown in the figure. It is moved in that direction by the pin inside pivot 33, as the leg-shaped lower handle 30 is rotated about its own pivot, 29. In other words, as the heel of the lower handle component moves towards the right, inevitably the actuator which is connected to it will move in the same direction. However, the actuator does not really move in a vertical direction. It has a rotational movement around the same pivot. The freedom of movement in all directions within a single plane, which give rise to the floating cam which is said to be the essence of the patentee's device, does not exist in the defendant's product.

32. It appears to me that a very similar overall effect is achieved in the defendant's device, but because the link has been dispensed with, the design of the actuator, its mounting and, indeed, the design of the other components, have had to be completely reworked. That they achieve the overall objective of causing the jaws of the stripper to come together at the early stage of the stripping operation, and then for the inner jaws to move relative to the outer jaws during the actual part of the procedure where it is stripping the plastic sheathing, is not in doubt. However, this is a function achieved by all the strippers I have referred to including, in particular, the strippers which the patent specification concedes to be prior art. Within that overall objective, the alleged infringement and the patented devices work in different ways. In my view it is unlikely that any engineer not involved in this litigation would look at the defendant's device and consider to it and its many working parts to be a mere variant of the device described and claimed in the patent specification. The former is a differently designed apparatus which achieves the same effect as the latter.

34. Mr. Miller reminds me that one must never forget that this is an explanation of how a court can approach the question of infringement but, in the end, the issue of infringement must be determined in accordance with the provisions of section 60 of the Patents Act 1977 and the Protocol on Interpretation.

36. The second question is, "Would this (i.e. that the variant had no material effect) have been obvious at the date of publication of the patent to a reader skilled in the art? If no, the variant is outside the claim". In view of what I have said in relation to the first question, I find it very difficult to apply this question at all in this case and I will move, instead, to the third question which is, "Would the reader skilled in the art nevertheless have understood from the language of the claim that the patentee intended that strict compliance with the primary meaning was an essential requirement of the invention? If yes, the variant is outside the claim".

37. Even if I had come to a different conclusion on the first question, I would have had very great difficulties in finding for the plaintiffs on the third question. This is not an apparatus which is the first of its kind, treading virgin territory and producing results of a type which have never been achieved before. It is a precise and carefully worked out arrangement of parts to achieve a known effect in a more convenient way. I am not persuaded that a reader skilled in the art would have understood from the language of the claim that the patentee did not intend that strict compliance with the primary meaning of the word was an essential requirement of the invention. On the contrary, I think a skilled reader would think that having a link was essential to the floating cam arrangement which the patentee says is the essence of his invention.

38. For these reasons, I have come to the conclusion that the allegation of infringement fails. Mr. Miller makes it clear that he is not advancing a case of invalidity, save in the circumstances that the court gives the claims such a wide scope as to read on to his client's product. I should say, however, that I have read the material relating to the attacks of invalidity. The claims having the meaning that I have given them above, it does not seem to me that any viable attack on validity has been made out. In these circumstances, I dismiss this action.