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England and Wales Court of Appeal (Civil Division) Decisions |
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You are here: BAILII >> Databases >> England and Wales Court of Appeal (Civil Division) Decisions >> Taylor v Ishida (Europe) Ltd & Anor [2001] EWCA Civ 1092 (12 July 2001) URL: http://www.bailii.org/ew/cases/EWCA/Civ/2001/1092.html Cite as: [2001] EWCA Civ 1092, (2001) 24(11) IPD 24070 |
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COURT OF APPEAL (CIVIL DIVISION)
ON APPEAL FROM CHANCERY DIVISION
MR JUSTICE PUMFREY
Strand, London, WC2A 2LL Thursday 12th July 2001 |
||
B e f o r e :
LADY JUSTICE HALE
and
LORD JUSTICE JONATHAN PARKER
____________________
Alfred Alexander Taylor | ||
and | ||
(1) Ishida (Europe) Ltd | ||
(2) Ishida Co. Limited |
____________________
Smith Bernal Reporting Limited, 190 Fleet Street
London EC4A 2AG
Tel No: 020 7421 4040, Fax No: 020 7831 8838
Official Shorthand Writers to the Court)
____________________
Crown Copyright ©
ALDOUS LJ:
"Background to the invention.
7. The invention is concerned with a machine for continuously packaging food products. A familiar example of the kind of package with which the patent is particularly concerned is the ubiquitous potato crisp packet. The package consists of a generally tubular bag which is heat sealed at each end. The tube is itself formed from a flat web of material, and the edges of the flat web are joined together with a continuous longitudinal seal. The machine that forms the bag, fills it and seals it is called a form, feed and seal or FFS machine. There are two classes of machines, horizontal (HFFS) and vertical (VFFS). The former are used for regularly shaped solid products, such as chocolate bars and the like. For loose confectionery and snack products, on the other hand, VFFS machines are used. In a VFFS machine the weighed product passes down the centre of a tubular former round which the web which will make the bag is wrapped. At this stage, the longitudinal seal is made in the web to form a cylinder. The product drops into the bottom of the web, which is sealed, and the upper seal is formed above the product, so forming the bag.
8. In the case of dense products (sweets, dried fruit, nuts and so on) there is no problem in getting the product into the tube and into the bag. With light products, such as potato crisps and other snackfoods, there is a problem getting the product into the bag in a reliable manner. Where the product is not dense, and has a propensity to float, the manufacturer must allow sufficient time, or take deliberate steps, to ensure that all the weighed product is in the bag before the top is sealed. It is most important to avoid what is called the "crisp in seal" problem. The main classes of product which exhibit this difficulty are potato crisps, tortilla-like products and various extruded products such as Hula Hoops and cheese puffs. I shall call these snackfood products.
9. By the priority date, it was known to use a technique called "stripping". Stripping is essential in VFFS machines used for snackfood products. Stripping in its simplest form consists of mechanically pinching the walls of the cylinder above the point at which the upper seal will be formed, and so to speak running the pinch down the cylinder to pick up any laggard items and push them into the region below the point at which the seal will be formed. Other methods (including devices like rammers in the filling and forming tube) have been proposed.
10. In a continuous VFFS machine, it will be understood that stripping and sealing are two essential operations. Sealing must be carried out by heated jaws of some description (nearly all bags are made without adhesive) which must remain in contact with the moving web for long enough for a reliable seal to be made. At the same time the bag must be stripped before it is sealed, and thus some method of moving a pinch faster than the bag is moving must be found, which will be capable of moving through the region where the jaws will close to form the seal, all this being done as the bag is in continuous motion. The evidence shows that a great deal of ingenuity has been expended by many manufacturers in seeking to come up with a solution to this far from straightforward mechanical problem, and it is the problem with which the patent in suit is concerned.
11. The evidence was that there were a large number of manufacturers of VFFS machines in the world in the early 1980's. The industry is competitive, and Mr Poley (Ishida's expert) and Mr James (Mr Taylor's expert) both gave evidence that so far as possible the competing manufacturers not only kept an eye on the state of the market but tried to find out as much as they could about the way in which their rivals' machines operated.
….
14. There were three basic classes of VFFS machines in use in the snack industry: reciprocating jaw types, reciprocating frame (or former) types and belt advance machines. In all three types, the web which will form the bag is run to a former round which it is shaped to form a tube, and the longitudinal seal is formed. The product is supplied through the former to come to a rest above the last seal formed. In the first type (reciprocating jaws) the former is fixed, and the seal is formed by a pair of reciprocating jaws which move in an essentially rectangular path. The jaws move towards each other, clamp the web and then move with the web for the period of time needed to form the seal. They unclamp, move away from each other and back towards their initial position. In the second class of machines, the web on the former is drawn along the former by two belts which grip the web. The belts move a suitable length of web through the jaws, and stop the movement. The jaws move in and seal, and move out. The belts move again. In the third class of machines the jaws close: the whole former with its tube moves upwards, pulling a further bag length, and permitting it to be filled; the jaws open and the whole descends to feed the new bag length through the jaws.
15. In each of these types of machine, a stripping mechanism could be combined with the reciprocating motion of the jaws or belts. Of these types of machines, the evidence was from Mr James that the most important were the reciprocating jaw types (he calls them draw-bar machines) and the intermittent belt drive with horizontal jaws (he calls them pull-belt machines).
16. Outside the snack food industry, with its requirement for verticality and stripping, there were a number of other machines. HFFS machines were very common. These commonly used a rotary movement of the jaws, as did VFFS machines for use without stripping for products other than snackfoods. These machines, of which the pleaded Rose Forgrove RF98 appears to have been an example, used jaws which rotated continuously. In a rotary jaw machine, the jaws rotate about parallel axes so that the face of each of the jaws describes a cylindrical locus. The web passes through the tangent line or lines of intersection of the cylinders and are thus sealed at regular intervals."
"In the packaging of many products, bag material is delivered to a sealing head, in tubular form. The product to be packaged is delivered to the sealing head and is located within the bag material. The bag material is sealed transverse of its longitudinal direction of extension, and then the material is located within the bag material. Thereafter, the tube is closed, a stripping apparatus condenses the volume occupied by the product to be packaged, and the bag material again sealed, so that the packaged material is located within a discrete bag. The bag is then severed from the tubular bag material. This packaging operation is generally intermittent, that is not continuous.
It is a disadvantage of known apparatus that the sealing, closing, stripping and severing of the bag is achieved by relatively complex apparatus which increases the cost of the machine as well as rendering the machine unreliable. Additionally these known apparatus operate intermittently, and accordingly are slow."
The specification then goes on to acknowledge and distinguish between 5 prior art patents. I do not need to deal with the first as it is irrelevant to the issues in this appeal. The second, called Crawford, discloses a rotary HFFS machine with no stripping means. It therefore provides no guidance as to how to produce a VFFS machine with stripping.
"27. ….
Figure A: Figure 1 of the patent
This figure shows the simplest schematic embodiment of the invention. The strippers are mounted in an assembly which slides over the sealing heads and are urged outwardly by the springs. The specification says (column 4 line 29) that the heads are moved towards each other and are moved in the direction of movement of the material 12 at a velocity greater than that of the material 12. Accordingly the heads will cause stripping of the bag material 12 to thereby reduce the volume occupied by the product 11. Upon the heads 14 reaching a predetermined position, the bag material 12 is sealed.
28. It should be noted that in order to achieve the movement described, the rotational speed (angular velocity) of the shafts will have to vary: the heads must travel faster than the web before sealing, and slower than the web after sealing. This problem forms the basis for one of Ishida's allegations of insufficiency.
29. The second embodiment (Figure 2 of the patent) looks like this:
Figure B: Figure 2 of the patent
30. The basic scheme of things is still the same, but now the stripper heads are constrained to move by cam tracks. The stripper bars are at 22 and it may be seen that again they are telescopically mounted with respect to the sealing heads. Again the specification makes it clear that the strippers must move faster than the web until the sealing heads engage.
31. The nature of the sealing heads themselves gave rise to a great deal of controversy at the trial. It will be observed that nothing is said about them at all in the specification. The reason they are so important is this. The only real question on construction of the claim is what the words "spaced parallel fixed axes" mean in the claim. The problem arises since it is not in dispute that in Ishida's machines the axes of rotation of both the heads move during a cycle in equal and opposite amounts towards and away from the web. They move under the control of the software, to provide that the heads moves in generally D-shaped paths in a way which I shall discuss in detail below. This enables the strippers, which are attached to the heads, to contact the web at a suitable point for stripping and enables the heads, which have a fixed radius of rotation, thereafter both to contact the web at a suitable point after stripping and remain in contact with the web for a suitable period of time to effect the seal. Ishida's first argument is that the words of the claim mean what they say, and that the axes are spaced apart from each other and fixed in position with reference to each other. To this contention, the reply is that such a contention is manifestly wrong. Sealing is not possible otherwise than by exerting a pressure between the faces of the sealing jaws. Such a pressure cannot be exerted otherwise than permitting a degree of movement and a conventional mechanical device for this purpose is shown (although not provided with an index number and not described) in Fig 3.
Figure C: Fig 3 of the patent—the linear guidance mechanisms
Moreover, it is pointed out that any designer of sealing machines would know that a rolling contact between two cylindrical jaws, as shown in the specification, can only apply pressure and heat to any one region of the web momentarily, certainly not long enough to form a seal. This is so even if the face of the jaws are as they always are, that is, serrated and complementary, so as to provide a wavy path for the web between them and stretch and compress it so as to assist the seal. Finally, it is said that there is no suggestion that only cylindrically faced jaws should be used: if flat faces are used, then the skilled man would realise that he must provide some means of providing a period of time during which the web is sandwiched between the flat jaw faces and the jaw faces are applying a pressure and moving at the same speed as the web. This, it is said, can only conveniently be done by permitting the axis to move laterally so as to accommodate the movements of the jaws necessary to conform with the movement of the web while providing a seal."
"A stripping and sealing assembly, for packaging apparatus,
(1) said apparatus including a product delivery head and a drive assembly
to pass tubular bag material (12) past said delivery head so that product delivered from said head is located within said tubular bag material (12),
(2) said stripping and sealing assembly including a pair of opposing sealing
and stripping means (14, 40, 41, 42) located on opposite sides of said bag material (12) at a position downstream from said delivery head relative to the direction of movement of said bag material (12) through said apparatus,
(3) said sealing and stripping means (14, 40, 41, 42) being adapted to
cooperate to sealingly close portions of said bag material (12) and strip same,
(4) a first arm means (15, 45) supporting one of said sealing and stripping
means (14, 40.41, 42) and a second arm means (15,45) supporting the other sealing and stripping means (14, 40, 41, 42),
(5) a pair of generally parallel rotatably driven shafts (16.43.44) from each of
which there extends radially outwardly therefrom one of the arm means (15, 45),
(6) cutting means (27, 46) mounted so as to be adjacent the extremities of the
arm means (15, 45) and adapted to cooperate to sever said sealed portions from said bag material (12) to thereby form discrete bags of said product and wherein
(7) each sealing and stripping means (14, 40,41, 42) includes co-operating
stripper bars (22, 49, 50) which strip the bag material (12); wherein the arm means (15, 45) via said shafts are rotatably driven continuously through complete revolutions in synchronism in opposite directions about spaced parallel fixed axes generally transverse of the direction of movement of the bag material (12)
(8) so that prior to sealing said bag material (12) the sealing and stripping
means (14, 40, 41, 42), are moved along said bag material (12) to cause the stripper bars (22,49, 50), to strip same,
and wherein
(9) each arm means (45) is provided with one of the stripper bars (22, 49, 50),
and the assembly further includes pivotable supports (19, 20, 53. 55, 47, 48, 57) for each stripper bar (49, 50) pivotally mounting the stripper bars (49 50) relative to said arm means (15,45) so as to provide for relative movement therebetween."
"43. In general terms the Ishida machines are VFFS machines in which the seal is effected by rotating sealing jaws. The jaws have flat faces and the faces are constrained to remain vertical and facing each other through an entire rotation by a planetary gear system. Strippers are fixed below the heads so that they engage with the film before the heads do. The film passes between the jaws at (for any particular mode of operation of the machine) a predetermined speed which is not necessarily constant. Each jaw rotates on a shaft and each shaft is mounted in a frame. The shafts may be moved together and apart under the control of a servo motor, the so-called turnbuckle motor. The shafts are geared together (their mutual movement being accommodated by couplings called Schmidt couplings clearly visible in the model) and are driven by a servo motor. The shafts rotate at a speed which varies through a rotation: they must both rotate so that the head follows the film during stripping but and so that the strippers move faster than the film during stripping. The turnbuckle motor moves the shafts so that the heads and their associate strippers move during the cycle to appropriate positions with respect to the film, and also drive the heads together during sealing (the so-called torque mode of the motor). The machine may be considered to have three servos (film drive, arm drive and turnbuckle drive) which are controlled by software."
"44. The arms rotate in a generally D-like locus. ….. When stripping is switched on, the movement is very D-like. This is the most general case (Figure D).
Figure D – Stripping on
In this Figure, the movement of one jaw only is shown by the heavy line (including the dotted portions CA and BD.) The jaw shown rotates anticlockwise. If one starts from point D: the arm, driven by the arm servo, rotates from D to C, and the axis remains stationary where XCD intersects the horizontal axis. From C to A the axis moves from XCD to XA [and accelerates]. The jaws move from A-F as the axis moves away from the film, from XA to XF. Then the jaws move together to seal, and between G and B the axes again move to keep the jaws in clamping relationship with the film. Then from B to D the jaws move towards the web [and the movement of axes decelerates]. During the whole of the cycle, the rotational speed of the jaws varies. In the parts of the cycle denoted by a thick line they move essentially at constant angular velocity, but CA and BD are regions of the cycle where there is [normally] angular acceleration [of the arm]."
"35. All rotary machines, on the evidence, permit one or both shafts a degree of movement to accommodate the fact that the surfaces of the jaws must touch through the web. The web is thin and high precision is not attainable, and so a degree of "give" must anyway be incorporated. But to apply pressure, the pitch circles of the jaws must be deliberately arranged to intersect, so that on contact one or both jaws recoils slightly. It is important not to exaggerate this effect, as the radii of curvature are comparatively large. A great deal of confusion was caused in the evidence by the suggestion that if the pitch circles marked out by the jaws intersect there will be a so-called D-shaped movement, so that the web is continuously pressed by the sealing jaws. Mr Taylor makes this suggestion in Appendix 5 to his report, where a contrast is made between a "point contact" arrangement and a spring loaded shaft. But there is no distinction as X3, put to Mr Taylor, makes clear. In fact what happens geometrically is that if the pitch circles of the jaws overlap, the jaws touch and remain just touching at the leading edge until horizontal dead centre is reached, when they roll past each other. The contact remains a rolling contact, but under higher pressure. Practically, the position is not so simple because at the leading edge the jaws are nipping the web, and beginning to form a seal, and the same happens at the trailing edge. In fact, the contact time of the web with the jaws is largely influenced by the profile of the surface of the jaws. But this is obvious, and all jaws for rotary machines appear on the evidence to have a generally wavy profile cut in them. To this extent paragraph 10.2 of Mr Taylor's report is not correct as a matter of geometrical fact. I should observe that Mr Taylor has conducted or is conducting litigation against Ishida in a number of jurisdictions. From time to time, particularly when giving evidence in relation to the disclosure of the patent, he stepped over the line and became an advocate. On the other hand, particularly when he was giving evidence in relation to the history of his development, and as to how, based on his observations, the Ishida machines operated, he was a satisfactory and reliable witness."
"36. It is convenient to deal with the question of flat-faced jaws at this stage. Flat-faced jaws (of the kind for example used in Zwight and Crawford) cannot be used in a purely rotary machine unless they are arranged to pivot, so that the faces of the jaws are parallel and move into positive engagement with the film as their support rotates. Such a movement is difficult to achieve mechanically (Crawford gets over it with his cam track for the heads and his barrel cam for varying the speed of rotation). With flat faced jaws, sealing time is directly measured. The position is different with jaws with a cylindrical surface. In the latter case, the relevant time is the time during which the softened, or molten, web material is in the nip between the jaws. Although the times are not directly comparable, Mr Taylor gave evidence that in fact the times were comparable, and he supported this contention by reference to his sketch X4.
37. Mr Taylor said that a machine with a "kissing" contact between the jaws would not work. He was adamant, under repeated cross-examination, that as a practical matter some give was absolutely necessary, and that it would be obvious to the skilled man that he could (within limits) increase the time during which the film was subjected to a sealing pressure by increasing the overlap of the pitch circles of cylindrical-faced jaws. So far as flat jaws are concerned, obviously they required substantial overlap of the pitch circles and (equally obviously) flat jaws were used to increase sealing time. On this question I accept Mr Taylor's evidence. The arguments to the contrary seem to me to turn excessively on a purely geometrical analysis of the problem (see for example X3) in which insufficient attention has been directed to the real dimensions of the components concerned and the realities of machinery rotating rapidly."
"38. In my view, if the axes move in a manner which is irrelevant to the basic requirements of the invention, such a movement is within the contemplation of the claim. I consider that a movement of the jaws normal to the web would be seen by the skilled man as inevitable if a seal was to be formed using cylindrical sealing faces and he would further appreciate that such a movement would be provided by the conventional spring guide arrangement shown in Figure 3 of the patent. I consider, therefore, that a movement normal to the web of the axis of rotation of one or both of the jaws the function of which is to ensure that the sealing jaws (a) follow the web as they rotate and (b) move so as to control the pressure or duration of the clamping action is within the claim. I think that this construction is really to put a sensible meaning on the word "fixed" in its context. It is certainly a variant on the acontextual meaning of the word, and it seems to me that the skilled man would both appreciate that it was a meaning which could have no effect on the way the invention worked—indeed, it is necessary for the invention to work practically—and it is certainly not excluded by the specification itself."
movement. Obvious ways of doing that were springs and servo motors. He believed that their use was undergraduate mechanics.
"64. Mr James, who worked for Hayssen at the material time and was apart from Mr Taylor the only witness who had experience of this packaging business from the inside did not consider that the solution of attaching the strippers to the jaws was obvious. He had himself experience of one arrangement (the Gausman 1 patent, US 2,950,588) in which flat-faced sealing jaws rotated. Gausman had a slightly later patent for a very elaborate stripper arrangement which passed between jaws of a reciprocating-jaw machine but the strippers were independently driven of the jaws which appear not to have rotated (US 2956383). Gausman 1 incidentally shows another method of accommodating the necessary movement of flat-faced sealing jaws: see Figure 7. So Mr James was conscious of the problem, and was aware of flat-faced rotary jaw machines and was aware of the need for stripping, but an arrangement within the patent in suit escaped him. The same goes for Bartlo, also employed by Hayssen and Mr Gausman's successor. He had invented the stripper mechanism disclosed in his patent which was pleaded, but he did not make the connection either."
"67. Of course, Mr Poley's report is an actual rather than a conjectural series of steps, and it is right also that Mr Poley did not start with any particular end in view. In the present case I think that the sum of the steps which I have outlined above in considering Mr Poley's report is, cumulatively, indicative of invention, albeit not of the flash of inspiration variety. But to go from the start to the end was in my judgment inventive, and my conclusion is that the claim is not invalid for obviousness over the common general knowledge."
"62. The approach of Mr Poley's report is rigorously systematic, but in no sense merely mechanical. He is himself an inventor with a number of patents to his name. The development was investigated in advance of the availability of weigh feeders capable of supplying 120 bags per minute from a single head. Phase 1 of the investigation, which was a design study, was the only work done by Mr Poley. He is a good engineer introduced to a new art, and he approaches the problem which he was given with none of the preconceptions of prejudices of the workers in the art themselves. He considered that it was obvious to rotate the strippers on the jaws, and Mr James disagreed.
63. Mr Poley's report proceeds by successive refinement. He sets out with a set of logical options for phase 1. He investigates how potato crisps drop in tubes. He identifies the need to avoid high accelerations and heavy components. He looks at the physics of film sealing. The report refers to brainstorming sessions for generating innovative concepts without consideration of the prior art. The results of these sessions were presented to Wright's for discussion. The report in fact contains an excellent step by step analysis of the design of a machine. Mr Poley did not come to the idea of attaching the strippers to the arms carrying the sealing heads immediately: his figure 6.15 in the first part of the report does not contain this feature, and it was after he had investigated the locus of the jaws and the locus of the stripper blade that he concluded that selection of a rotary stripping mechanism would allow elimination of a separate strip drive motor. I should record that Mr Poley's evidence taken as a whole both in his report or under cross-examination left me with the clear impression that the invention was not obvious. Mr Kitchin identified I think seven successive distinct steps in Mr Poley's design: (1) the brainstorming sessions (2) the investigation of the drop characteristics of potato crisps (3) the production of a number of different design concepts, including a design with independently driven strippers and sealing jaws (4) selecting between the different approaches (5) investigation of the different approaches to stripping through the sealing zone, and identification of reciprocating, rotary and track strippers and sealers, but without any particularly driving means (6) analysis of kinematics of the stripping and sealing mechanisms (7) the final design. Mr Kitchin points to the fact that PA considered that at the step 6 stage they had made a significant development."
HALE LJ:
JONATHAN PARKER LJ: