Ancon Ltd v ACS Stainless Steel Fixings Ltd

The Claimant, Ancon Limited (“Ancon”), is the registered proprietor of European Patent (UK) No. 0882164 entitled “Channel Assembly” (“the Patent”). It claims that the Patent has been infringed by a channel assembly produced and supplied by the Defendant, ACS Stainless Steel Fixings Limited (“ACS”), known as the ACS 31/21 channel assembly. This is made up of a channel and T-head bolt assembly which is used to provide heavy duty fixings for use in the construction industry.

Infringement is alleged of claims 1-12 of the Patent, of which claims 1, 3, 6, 9 and 12 are said to be independently valid. But there seems to be a measure of agreement that the issue of infringement can be determined by reference to the construction of claims 1, 3 and 6, although claim 6 may add little or nothing to claim 3.

The priority date is 9^th December 1995.

ACS denies that it has infringed the Patent but, in its counterclaim, it also asserts that the Patent is invalid over three pieces of prior art:

There is also a counterclaim by ACS for unjustified threats based on allegations that in August 2006 representatives of Ancon suggested to some of ACS’s customers that the channel sections supplied to them infringed the Patent and were illegal. Since this counterclaim is dependent on the issues of infringement and validity, the parties agreed that I should adjourn it until after giving judgment on the principal issues.

Channel assemblies have been in use in the construction industry for some time. Typically they are made up of a metal channel with lugs or restraining anchors which is cast into the concrete structure of a building. The channel has shaped sides with an open aperture on its face into which the head of the bolt can be inserted. The bolt is moved along the channel to its required position and then turned 90º so as to lock against the internal walls of the channel. The assembly can then be used to fix on to the structure of the building components such as brackets to support masonry or some other form of external cladding.

These fixings must therefore be able to support extremely heavy loads and the evidence is that they can carry weights of up to ¾ tonne which is the weight of a small car.

The Patent describes the invention as relating to “a channel assembly which is adapted to be cast into or otherwise attached to a building structure”. It explains by reference to the assemblies shown in Figures 1-4 that channel assemblies have been used for many years for fixing ancillary components to a building structure. The channels are either surface mounted or cast into a concrete face and “generally have a rectangular-shaped cross-section with an open slot 5 between two lips 7 which are turned inwards from generally parallel side walls 8”.

The Patent then goes on to explain at [0003-0004] the problems with the existing systems:

“[0003]The channel 1 is used in conjunction with a bolt 10 with a generally T-shaped head having two wings 12. The bolt head fits into the open slot 5 in the channel 1 and is turned through 90º in a clockwise direction which locks the bolt 10 in position (the tips 12a of the wings 12 abut against the side walls 8 to prevent further rotation of the head). Conventionally, the fit of the head in the channel 1 is fairly loose. This can allow significant movement of the bolt 10 in the channel 1 under shear loads. Under tensile load the lips 7 of the channel 1 can deflect outwards and the wings 12 of the bolt 10 bend because the load is transferred from the head of the bolt 10 to the lips 7 of the channel 1 at a location remote from the sides 8 of the channel 1.

[0004]Under tensile load, the channel 1 behaves as a beam between the bolts securing the channel 1 to the structure or between anchorage lugs 15 which secure the channel 1 in the concrete.”

These features are illustrated in Figures 1-4 below:

In paragraphs [0006-0011] the Patent describes the invention as follows:

“[0006] According to the present invention there is provided a channel assembly in accordance with claim 1.

[0007] The sides of the head (or a portion thereof) are preferably inclined at substantially the same angle as the side walls of the channel.

[0008] The fixing and channel preferably co-operate (preferably by a cam action) to force the fixing against the means for restraining it upon rotation of the fixing in the channel.

[0009] Thus the invention also provides a method of securing a fixing in a channel assembly as defined above, the method comprising providing a channel assembly as defined above, locating the fixing in the channel, and rotating the fixing in the channel to engage the sides of the head and the side walls of the channel such that a camming action forces the head of the fixing against the lips of the channel.

[0010] The invention also provides a fixing for use in the channel assembly as defined above.

[0011] The head of the fixing is of an elliptical cone. In the embodiment comprising an elliptical cone, the rotation of the head in the channel optionally forces the sides of the head at its largest radius against the side walls of the channel, and can also force the head against the lips of the channel. This can reduce the extent of play of the fixing in the channel, and allow a stronger fixing than if the bolt is movable in the channel.”

The two key features used to achieve the effect described in [0011] are therefore (1) the shape of the channel which has sides which “incline inwardly towards a spine” compared with the examples in the prior art which are rectangular in shape and (2) the head of the bolt which is described in [0016] as having a generally frusto-conical shape in side view with tapered sides. These are references to Figures 5 and 6 in the Patent which illustrate the first embodiment of the design and is a more detailed description of the head of the fixing which in [0011] is simply referred to as “of an elliptical cone”.

In [0017-0018] the Patent explains the relationship between the shape of the head and that of the channel:

“[0017] The angle of the tapered sides of the head 33 at its widest point approximately equals the angle of inclination of the sides 28 of the channel 21. At the base 33a of the head 33 there is a plate which is similar in plan view to the head of the prior art bolt 10. The head 33 has two flattened areas 33c on opposing sides to enable the head 33 to be inserted into the slot 25. Once in the slot 25, the head 33 can be turned clockwise through 90º but the plate prevents further rotation in the channel as described for the prior art.

[0018] Rotation of the head 33 in the channel 21 induces a camming effect between the head 33 and the channel 21 which forces the base 33a of the head 33 against the inner surfaces of the lips 27. This not only ensures that the rotated bolt 30 is restricted in its axial movement by the lips 27, but also transfers any axial load from the bolt to the channel 21 at the corners between the lips 27 and the side walls 28.”

There are two further embodiments. Paragraph [0019] teaches a modified form of the head “in the form of a truncated elliptical cone” in which the base plate (33a in Figure 6) is removed. This is illustrated in Figures 10 and 11 below:

Paragraph [0019] says that:

“…The cross-section through the head 34 is generally elliptical as shown in Fig. 11. The head 34 has flattened areas 34c as previously described for the head 33 which allows the head 34 to fit into the slot 25 of the channel 21. Upon rotation of the head 34 in the channel 21, the head 34 is forced upwards in the channel towards the slot 25 by the camming action of the inclined sides of the head 34 and channel 21 respectively, and the base 34a of the head 34 is firmly locked against the inner surface of the lips 27.”

Figures 12 and 13, which are reproduced below, illustrate the third embodiment which is a further variant of the truncated elliptical cone described in Figures 10 and 11.

This version of the head (which, like the other two, is designed to fit into the channel illustrated in Figure 5) also has flattened areas on two sides and a flattened top. But it differs from the one shown in Figure 10 (34). Paragraphs [0020-0021] state that:

“[0020] ….whereas the head 34 is generally symmetrical about a line B-B joining the mid points of its flattened areas 34c so that the vertices between the curved and flat portions are generally rounded, the head 35 has two diametrically opposed rounded corners 35r and two diametrically opposed right angled corners 35L at its base 35a. The head 35 is shaped such that the sides incline smoothly from the base 35a to the tip 35b. As previously described, the head 35 has flattened areas 35c on opposing sides.

[0021] When fitted to the shank of a bolt, the head 35 can fit into the slot 25 of the channel 21 as previously described. Upon clockwise rotation of the head 35 in the slot 25, the sides 28 of the channel 21 contact diametrically opposed sides of the head 35, such that the head 35 can be turned when the rounded sides 35r are in contact with the sides 28 of the channel 21, but once the corners 35L of the head 35-are in contact with the sides 28 of the channel 21, further rotation is resisted by the generally flat sides 35F adjacent the respective corners 35L. The surface area of the head 35 available to abut against the side walls 28 of the channel 21 is increased as compared to the surface area available on the bolt 30; this improves resistance to further rotation, and increases the camming force which drives the base 35a against the lips 27 when the head 35 is rotated in the channel 21.”

The advantages claimed for the invention in the Patent are a higher load capacity within a given deflection limit and a lower metal volume for any given overall performance. Although containing less metal, the fit of the bolt head into the channel transfers load to the channel at a location very close to the side walls which can reduce the deflection caused by the bending of the lips of the channel under tensile load. In turn, the shape of the channel with its inclined sides is said to transfer the load more directly to the anchorages than would be the case with the traditional triangular shaped channel thereby further reducing the possibility of deflection. There is also a corresponding reduction in the amount of metal required to form the channel.

There are 13 claims as follows:

“1.

A channel assembly (21) adapted to be attached to a building structure, said channel comprising a spine (29), two side walls (28) and lips (27) defining a slot (25) in the channel and adapted to restrain a fixing in the channel, said spine (29) being provided with anchors (31) for casting into concrete, said side walls (28) being inclined inwardly towards the spine (29) and further including a fixing (30) having a head (33) with inclined sides characterised in that the head (33) has a generally elliptical cone shape.”

2.

A channel assembly as claimed in Claim 1, wherein at least a portion of the sides of the head (33) are inclined at substantially the same angle as the side walls (28) of the channel.

3.

A channel assembly as claimed in Claim 1 or 2, wherein the head (33) of the fixing is shaped such that the head (33) is forced against the lips (27) of the channel upon rotation of the fixing (30) in the channel.

4.

A channel assembly as claimed in Claims 2 or 3 wherein the head (33) has flattened portions (33C) on its sides to allow access of the head through the channel slot (25).

5.

A channel assembly as claimed in any one of Claims 2 to 4, wherein the head (33) of the fixing has flattened areas (35F) thereon to resist further rotation in the channel.

6.

A method of securing a fixing in a channel assembly according to Claim 1, the method comprising providing a channel assembly according to any one of Claims 1 to 5, locating the fixing (30) in the channel (21), and rotating the fixing in the channel to engage the sides of the head (33) and the side walls (28) of the channel such that a camming action forces the head (33) of the fixing against the lips (27) of the channel.

7.

A fixing for use in the assembly of Claim 1, wherein the fixing (30) has a head (33) which has a generally elliptical cone-shape.

8.

A fixing as claimed in Claim 7, wherein the cone shape is a truncated cone-shape.

9.

A fixing as claimed in Claim 7 or 8, wherein the angle of inclination of the sides of the head (33) varies at different points on the radius of the head.

10.

A fixing as claimed in any one of Claims 7 to 9, wherein the head (33) has flattened portions (33C) on its sides to allow access of the head through a channel slot (25).

11.

A fixing as claimed in any one of Claims 7 to 10, wherein the head (33) of the fixing has flattened areas (35F) thereon to resist further rotation in the channel (21).

12.

A fixing as claimed in any one of claims 7 to 11, wherein the head (33) has two diametrically opposed rounded corners (35r) and two diametrically opposed right angled corners (35L) at its base (35a).

13.

A fixing as claimed in any one of Claims 7 to 12, wherein the sides of the head incline smoothly from the base to the tip.”

As already explained, the issues of infringement and validity can probably be determined simply by reference to claims 1, 3 and 6. Claim 1 encapsulates the channel and its shape together with the bolt head with inclined sides and a “generally elliptical cone shape”. Claims 3 and 6 cover the effect of the shape of the head which, when rotated, creates the camming action which forces the head against the lips of the channel.

Claims 7-13 embody the basic technology of claim 1 but cover the two variants in the shape of the bolt head illustrated in Figures 10-13.

The principal issue on infringement turns on the references in the Patent and claims to the bolt head having a “generally elliptical cone shape”: see claims 1 and 7. This, says ACS, is a (perhaps the) defining feature of the channel assembly taught by the Patent and applies even when the cone shape at the head is truncated or reduced by the creation of flattened areas and sides as in the two variants illustrated by Figures 10 and 12.

The top of the bolt head shown in Figure 10 remains generally elliptical despite its truncation and flattened sides and the bolt as a whole takes on a generally elliptical shape. In the case of the variant in Figures 12 and 13, the two right-angled corners at the base do not interfere with the ellipse at the top and each embodiment retains an identifiable elliptical shape and is generally conical.

ACS says that, by contrast, the bolt head in their 31/21 channel assembly is neither elliptical nor cone shaped and does not therefore infringe the claims in the Patent. If, on the other hand, the claims in the Patent are not to be construed as restricted to generally elliptical cone shaped heads (properly so-called) then they submit that the teaching is covered by the bolt and channel assemblies of the prior art and is, in any event, both lacking in invention and insufficient.

Not surprisingly, both sides are in agreement about the general approach to the construction of the claims in the Patent. As Lord Hoffmann made clear in Kirin-Amgen Inc. v Hoechst Marion Roussel Ltd [2005] RPC 9 (at para 34),

“The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean.”

That decision has imported into the law of patents the now well-established principles of construction (or, at least, the explanation of them) set out in Lord Hoffmann’s earlier speeches in Mannai Investment Co Ltd v Eagle Star Life Assurance Co Ltd [1997] AC 749 and Investors Compensation Scheme Ltd v West Bromwich Building Society [1998] 1 WLR 896. These are conveniently summarised by Lord Hoffmann in paragraph 32 of his speech in Kirin-Amgen where he says that:

“32.

Construction, whether of a patent or any other document, is of course not directly concerned with what the author meant to say. There is no window into the mind of the patentee or the author of any other document. Construction is objective in the sense that it is concerned with what a reasonable person to whom the utterance was addressed would have understood the author to be using the words to mean. Notice, however, that it is not, as is sometimes said, "the meaning of the words the author used", but rather what the notional addressee would have understood the author to mean by using those words. The meaning of words is a matter of convention, governed by rules, which can be found in dictionaries and grammars. What the author would have been understood to mean by using those words is not simply a matter of rules. It is highly sensitive to the context of, and background to, the particular utterance. It depends not only upon the words the author has chosen but also upon the identity of the audience he is taken to have been addressing and the knowledge and assumptions which one attributes to that audience. I have discussed these questions at some length in Mannai Investment Co Ltd v Eagle Star Life Assurance Co Ltd [1997] AC 749 and Investors Compensation Scheme Ltd v West Bromwich Building Society [1998] 1 WLR 896.”

But, as he himself recognised, patent specifications are usually the product of skilled advice and drafting and the starting point will normally be to assume that the patentee has chosen his language with care. In most cases, the correct meaning of the words used will not therefore depend on attempting to make sense of the kind of literal mistake which featured in ICS and in the examples of malapropism given in Mannai. It will be a matter of deciding whether the patentee has, by the use of a particular word or phrase, chosen to describe his invention (and so limit his monopoly) according to the strict technical meaning of the term or has used it in a more descriptive and therefore less exact way.

This has long been a problem in relation to the construction of patents and in Catnic Components Ltd v Hill & Smith Ltd [1982] RPC 183 the House of Lords had to consider a patent relating to steel lintels for use over apertures in cavity walls which incorporated as part of the design “a second rigid support member extending vertically from or from near the rear edge of the first horizontal plate or post to join with the second plate or post”. Although the infringing design was essentially the same, its second support member stood some 6º to 8º from the vertical. The House of Lords held that the claims had to be given a purposive rather than a literal interpretation and upheld the claim to infringement.

Lord Diplock (at page 236) said that:

“My Lords, a patent specification is a unilateral statement by the patentee, in words of his own choosing, addressed to those likely to have a practical interest in the subject matter of his invention (ie “skilled in the art”), by which he informs them what he claims to be the essential features of the new product or process for which the letters patent grant him a monopoly. It is those novel features only that he claims to be essential that constitute the so-called “pith and marrow” of the claim. A patent specification should be given a purposive construction rather than a purely literal one derived from applying to it the kind of meticulous verbal analysis in which lawyers are too often tempted by their training to indulge. The question in each case is: whether persons with practical knowledge and experience of the kind of work in which the invention was intended to be used, would understand that strict compliance with a particular descriptive word or phrase appearing in a claim was intended by the patentee to be an essential requirement of the invention so that any variant would fall outside the monopoly claimed, even though it could have no material effect upon the way the invention worked.

…..

The essential features of the invention that is the subject of Claim 1 of the patent in suit in the instant appeal are much easier to understand than those of any of the three patents to which I have just referred; and this makes the question of its construction simpler. Put in a nutshell the question to be answered is: Would the specification make it obvious to a builder familiar with ordinary building operations that the description of a lintel in the form of a weight-bearing box girder of which the back plate was referred to as “extending vertically” from one of the two horizontal plates to join the other, could not have been intended to exclude lintels in which the back plate although not positioned at precisely 90º to both horizontal plates was close enough to 90º to make no material difference to the way the lintel worked when used in building operations? No plausible reason has been advanced why any rational patentee should want to place so narrow a limitation on his invention. On the contrary, to do so would render his monopoly for practical purposes worthless, since any imitator could avoid it and take all the benefit of the invention by the simple expedient of positioning the back plate a degree or two from the exact vertical.

It may be that when used by a geometer addressing himself to fellow geometers, such expressions descriptive of relative position as “horizontal”, “parallel”, “vertical” and “vertically” are to be understood as words of precision only; but when used in a description of a manufactured product intended to perform the practical function of a weight-bearing box girder in supporting courses of brickwork over window and door spaces in buildings, it seems to me that the expression “extending vertically” as descriptive of the position of what in use will be the upright member of a trapezoid-shaped box girder, is perfectly capable of meaning positioned near enough to the exact geometrical vertical to enable it in actual use to perform satisfactorily all the functions that it could perform if it were precisely vertical; and having regard to those considerations to which I have just referred that is the sense in which my opinion “extending vertically” would be understood by a builder familiar with ordinary building operation. Or, putting the same thing in another way, it would be obvious to him that the patentee did not intend to make exact verticality in the positioning of the back-plate an essential feature of the invention claimed.”

This approach has been treated by Lord Hoffmann in Kirin-Amgen as an early example of a departure from literalism and its replacement by a concentration on what the patentee can reasonably be assumed to be communicating to the skilled person in relation to the teaching of the invention and the claims based upon it. In paragraph 33 of Kirin-Amgen it is put in this way:

“33.

In the case of a patent specification, the notional addressee is the person skilled in the art. He (or, I say once and for all, she) comes to a reading of the specification with common general knowledge of the art. And he reads the specification on the assumption that its purpose is to both to describe and to demarcate an invention - a practical idea which the patentee has had for a new product or process - and not to be a textbook in mathematics or chemistry or a shopping list of chemicals or hardware. It is this insight which lies at the heart of "purposive construction". If Lord Diplock did not invent the expression, he certainly gave it wide currency in the law. But there is, I think, a tendency to regard it as a vague description of some kind of divination which mysteriously penetrates beneath the language of the specification. Lord Diplock was in my opinion being much more specific and his intention was to point out that a person may be taken to mean something different when he uses words for one purpose from what he would be taken to mean if he was using them for another. The example in the Catnic case was the difference between what a person would reasonably be taken to mean by using the word "vertical" in a mathematical theorem and by using it in a claimed definition of a lintel for use in the building trade. The only point on which I would question the otherwise admirable summary of the law on infringement in the judgment of Jacob LJ in Rockwater Ltd v Technip France SA (unreported) [2004] EWCA Civ 381, at paragraph 41, is when he says in sub-paragraph (e) that to be "fair to the patentee" one must use "the widest purpose consistent with his teaching". This, as it seems to me, is to confuse the purpose of the utterance with what it would be understood to mean. The purpose of a patent specification, as I have said, is no more nor less than to communicate the idea of an invention. An appreciation of that purpose is part of the material which one uses to ascertain the meaning. But purpose and meaning are different. If, when speaking of the widest purpose, Jacob LJ meant the widest meaning, I would respectfully disagree. There is no presumption about the width of the claims. A patent may, for one reason or another, claim less than it teaches or enables.”

What Kirin-Amgen also establishes is that the approach in Catnic is in conformity with Article 69 of the EPC which provides that:

“The extent of the protection conferred by a European patent or a European patent application shall be determined by the claims. Nevertheless, the description and drawings shall be used to interpret the claims.”

As Lord Hoffmann explains in Kirin-Amgen, this represents a compromise between the UK principle of using the claims in a patent to determine the scope of the monopoly and the unwillingness of other Contracting States to accept an over-literal approach to the construction of those claims. The balance (or compromise) is explained in the “Protocol on the Interpretation of Article 69” (which, like Article 69, is part of English law: see Patents Act 1977 sections 60 and 125) as follows:

"Article 69 should not be interpreted in the sense that the extent of the protection conferred by a European patent is to be understood as that defined by the strict, literal meaning of the wording used in the claims, the description and drawings being employed only for the purpose of resolving an ambiguity found in the claims. Neither should it be interpreted in the sense that the claims serve only as a guideline and that the actual protection conferred may extend to what, from a consideration of the description and drawings by a person skilled in the art, the patentee has contemplated. On the contrary, it is to be interpreted as defining a position between these extremes which combines a fair protection for the patentee with a reasonable degree of certainty for third parties."

It might be said that the Protocol raises more questions than it answers but some guidance as to how to achieve the balance referred to is contained in paragraphs 47-48 of Lord Hoffmann’s speech:

“47 ……The claims must be construed in a way which attempts, so far as is possible in an imperfect world, not to disappoint the reasonable expectations of either side. What principle of interpretation would give fair protection to the patentee? Surely, a principle which would give him the full extent of the monopoly which the person skilled in the art would think he was intending to claim. And what principle would provide a reasonable degree of protection for third parties? Surely again, a principle which would not give the patentee more than the full extent of the monopoly which the person skilled in the art would think that he was intending to claim. Indeed, any other principle would also be unfair to the patentee, because it would unreasonably expose the patent to claims of invalidity on grounds of anticipation or insufficiency.

48.

The Catnic principle of construction is therefore in my opinion precisely in accordance with the Protocol. It is intended to give the patentee the full extent, but not more than the full extent, of the monopoly which a reasonable person skilled in the art, reading the claims in context, would think he was intending to claim…..”

In this particular case the issues of construction are relatively narrow. They turn on the meaning of the phrases “generally elliptical cone shape” and “forced against the lips of the channel”. The first raises the question considered in Catnic of how literal or exact the language used was intended to be.

The construction of the claims is, of course, a matter for me but the relevance of the factual matrix and the need to identify what the person skilled in the art would have understood the patent to be teaching has led inevitably to evidence from the expert witnesses designed to assist on this question. Ancon has called as an expert Mr Peter Harrison. He has considerable experience as a designer of fixings for stone and other cladding materials including the type of cast-in channels which feature in this litigation. He has worked in the industry since 1967 and has lectured and published material on stone and concrete cladding including fixing designs. ACS relies on the expert evidence of Professor Norman Fleck FRS. He is Head of Mechanics, Materials and Design at Cambridge University and has, since 1990, also been the Director of the Cambridge Centre for Micro Mechanics. He is a Chartered Engineer and has (apart from his research papers) acted as a consultant to a number of engineering companies.

Both experts are, I think, in substantial agreement about the identity of the skilled person to whom the Patent is directed. It would be someone interested in fixings for building structures (Professor Fleck) or professionals who design and develop fixing systems for the exterior façades of buildings (Mr Harrison). Professor Fleck considers that such a person is likely to have an engineering degree or other professional qualifications. Mr Harrison suggests a slightly lower level of skilled person. But the addressee is, in my judgment, likely to be someone familiar with basic engineering principles and will inevitably include a class of professionals or semi-professionals, some of whom at least will have the qualifications referred to by Professor Fleck.

ACS’s case on the meaning of “generally elliptical cone shape” is that the phrase comprehends modifications to the basic elliptical and conical shape of the bolt head such as the truncation of the cone and the flattening of its sides but not to a degree which obliterates its basic shape. They say that the Patent teaches the advantages of using a fixing whose head is an elliptical cone in order to achieve the camming action with the side walls of the channel and the contact between the head of the bolt and the lips of the channel. Although the shape of the bolt head is modified in the two variants described in paragraphs [0019 and 0020] by truncating the cone, flattening the sides and (in the second variant) by including the diametrically opposed right-angled corners, the head illustrated in Figures 12 and 13 remains the “truncated elliptical cone” shown in Figures 10 and 11.

This approach is supported by Professor Fleck who says in his report that terms such as “elliptical cone” and “truncated cone shape” have a fixed and obvious meaning. An ellipse has a precise technical meaning: i.e. a smooth oval shape with two principal radii of curvature. Similarly, the definition of a cone is also precise. Where the language used in the Patent becomes more ambiguous is when it qualifies the phrase “elliptical cone shape” with the word “generally”. This creates a phrase which Professor Fleck describes as a vague term not commonly used in technical literature. He considers that the use of the word “generally” in the Patent conveys what he calls “the notion of slight modification from the rigorous shape of an elliptical cone”. A skilled person would treat it as referring to a cone of elliptical cross section with a slight modification in shape.

Mr Harrison takes a broader view. In his reports he says that a fixings designer would have understood the term to refer to the range of shapes with curved surfaces capable of achieving the camming effect described in the Patent. “Generally elliptical” would have been understood to indicate that an exact geometric shape was not being identified and that the author of the Patent was suggesting a range of shapes which, when rotated, varied in radius. The description “cone shaped” would have been understood as requiring sloping sides to enable the bolt to cam in the channel and to achieve an efficient fixing by applying the load at the junction of the inclined side walls and the lips. In his report, he disagrees with Professor Fleck’s view that the word “generally” suggests only slight modifications from a precise geometric shape. He says that it connotes a range of shapes, provided that they achieve the same curved sloping surface and the varying radius described.

Mr Harrison was cross-examined about these passages in his written report. It was put to him (and he accepted) that in Figures 10 to 13 the head of the fixing (at least, in its upper portion around the truncated top) remains elliptical and that this would have been apparent to the skilled addressee. He was asked to confirm that the right-angled corners in the third embodiment (Figures 12 to 13) are introduced to prevent the head turning more than 90º but that the elliptical top is retained. Mr Harrison accepted that in the drawings in all embodiments there is an elliptical shape all the way round the top of the bolt and that the addressee would have assumed that this was something of importance for the patentee.

ACS therefore contend that the construction of the Patent contended for by Mr Harrison in his first report is far too broad and ignores the language of the claims completely. It would amount to saying that any geometry which works in the manner described in the Patent falls within the scope of the claims. Their argument, in linguistic terms, is that a head which has a generally elliptical cone shape cannot include examples which are not elliptical at all.

Although the views of the two experts on this issue of construction are helpful in identifying the parameters of the dispute, they inevitably contain elements of advocacy. It seems to me that, in attempting to ascertain what the Patent would have been understood by the skilled addressee to be describing, it is important to begin with what was common knowledge to those skilled in the art at the time in 1995. There is a considerable measure of agreement about this.

As mentioned earlier, channel assemblies pre-date December 1995. The best evidence of this is contained in the Patent itself which describes and illustrates in Figures 1 to 4 (above) typical examples of the prior art. These show channels which are essentially rectangular in shape and T-headed bolts with right-angled flat sides and a single curved edge to assist in rotation in the channel. The evidence is that channels and T bolts were illustrated in various trade manuals and brochures at the time as a means of providing supports for cladding systems. Both experts have exhibited examples of these. Professor Fleck has produced an Ancon design service document from February 1989 and a Frimeda brochure from July 1985, both of which depict channel and bolt assemblies in which the channel is essentially rectangular in shape although, in some cases, with lips which are angled upwards towards the spine of the channel section. Some of the bolt heads incorporate the rounded edge shown in Figure 2 of the Patent but they all have uniformly square sides at right-angles to the flat surface of their heads. The HEMAX channel sections exhibited by Mr Harrison from the 1993 Harris & Edgar brochure has similar designs, although in one example the channel section is slightly dovetailed in shape with the spine being wider than the distance between the lips at the aperture so as to create a more secure fixing. The bolt heads all have square or rectangular flat sides at right angles to an upper flat surface. None is remotely conical in shape nor are any of the channel sections sloped (as in the Patent) with sides which slope outwards from the spine.

It is clear from this material that it was also common knowledge at the time that the channel assembly provided an efficient and flexible means of creating fixings to support cladding compared to fixed position expansion anchors which had been on the market in the 1990s; that the easy insertion of the bolt head into the pre-cast channel required the head to be T-shaped rather than square in design; and that its rotation in the channel to a locked position was enhanced by rounding off one of the right-angled corners. Camming was also, of course, a well known and commonly taught engineering technique, although not one which appears to have achieved any particular significance in relation to channel assemblies in the literature which has been produced. I accept, however, that it would have been readily understood by the addressee of the Patent.

Against this background, what would the skilled person have taken the references to “generally elliptical cone shape” to mean? The first thing to note is that this phrase (although the basis of claim 1 and the other dependent claims) does not appear in the specification until one gets to the discussion of the first of the two variants in paragraph [0019]. Up to then, the Patent concentrates on the defects in the existing designs of channel assemblies and the tendency of the bolt to shift and the lips to deflect under sheer and tensile loads: see paragraph [0003]. This type of fixing and the problems inherent in its design would have been familiar to the addressee and common knowledge at the time.

The invented solution begins at paragraph [0005]. After referring to the shape of the channel described in Dennis, the Patent explains how, by the use of a bolt head shaped so as to incline at substantially the same angle as the side walls of the channel, both parts of the assembly cam together so as to force the head of the fixing against the lips of the channel thereby reducing play and creating a stronger fixing. In this general part of the Patent, its specification and in the first embodiment (see paragraph [0011]) the head of the fixing is an elliptical cone. But paragraph [0013] teaches that the head can be T-shaped and in the subsequent two embodiments the shape of the head is modified, first by the removal of the plate; the truncation of the cone and the flattening of portions at the sides and, secondly, by the creation of the two right-angled corners at the base of the head to limit the rotation of the fixing.

Both experts, I think, accept that the addressee would have appreciated that the important characteristic of the elliptical shape referred to in paragraph [0011] was that, as the fixing rotated around its axis, the distance between its surface and the axis changed smoothly. The importance of the cone shape was that its surface was angled so that it was in contact with the inclined walls of the channel in order to achieve the desired camming effect on rotation. Something which Mr Harrison referred to as a snug fit. This is set out in paragraph 61 of Mr Harrison’s first report and was assented to by Professor Fleck in cross-examination.

Whilst maintaining that the same functionality might be produced by a different design of bolt head, Professor Fleck accepted that the benefits taught by the Patent were delivered by the generally elliptical cone shape described. He was then cross-examined at some length by Mr Alexander as to what changes could be made in the elliptical cone before these benefits were lost. What, I think, emerged from this was a disagreement as to how far the terms of the Patent extend beyond the elliptical shape (in embodiment 1) which it is common ground does achieve the advantages which the Patent teaches. Mr Alexander sought to obtain from Professor Fleck an acceptance that what the Patent is seeking to identify in its various embodiments are the characteristics of the bolt head and the channel which are necessary to achieve the benefits set out in paragraphs [0022-0024]. He put to him that in relation to Figure 12 the rounded corners which are also angled towards an apex embody the two defining characteristics of a cone. Professor Fleck thought that this would be too broad a definition of a cone but accepted that the features of the chosen shape illustrated were useful features in allowing for the necessary camming action. His fallback position remained that, because other shapes would function in the same way, he could not accept that the Patent should be read as extending to a wider range of shapes than those specified in the claims. This can be illustrated from the following short exchange:

“Q. If camming takes place in any of those designs, it does not take place round the curved inclined surface which is characteristic of an elliptical cone, that is right, is it not?

A. They in each case will cam along a curved inclined surface. Many objects can contain curved inclined surfaces but in none of these cases would I describe them as being a generally elliptical cone. Mr. Harrison's definition as I understand it in his reports is that the definition if you will of a generally elliptical cone is something which is curved and inclined. I would state -- my view is that that is too broad a definition of an elliptical cone.”

An important part of Ancon’s case is the submission that the claims of the Patent have to be construed having regard to the purpose of the relevant requirement. Using the facts of Catnic as an example, the reference to a “vertical” support falls to be construed by reference to the function which the support performs. The support used in the infringing product was not strictly vertical but was vertical enough to work in the way taught by the Patent.

One needs to be careful about purpose having regard to Lord Hoffmann’s references to the use of the term in Rockwater. But I do not take his criticism to mean that the purpose or function of the invention is irrelevant; all he is saying is that it is not determinative.

The technical purpose of the invention was a topic raised in a cross-examination of both experts. Mr Harrison was asked about paragraph [0019] of the Patent which refers to the camming action of the inclined sides and the locking of the head against the inner surface of the lips. He said that this passage (and further references to it in claims 3 and 6) was the benefit of the invention and would have been seen as such by the addressee. The advantage of the third embodiment (see paragraph [0021]) was the increased surface area available to abut against the side walls.

He was also asked about the camming abilities of other shapes when used in conjunction with a V-shaped channel. Specifically it was put to him that even the prior art bolts with conventional diametrically opposed curved corners would cam up such channel when rotated. His evidence was that any camming action that occurred would not allow the bolt to cam up into the corners. On this he is in disagreement with Professor Fleck but the issue really turns on how close the fit will be:

“MR. LYKIARDOPOULOS: All I am putting, and I think I have your answer, is that you have seen that Prof. Fleck says that any non-circular bolt, particularly one with curved corners that we have seen in the prior art, will cam up a V-shaped channel? That is correct, is it not?

A. It moves up the channel but it is not a snug fit at the end which is what the other part of the patent tells me.

Q. In a V-shaped channel, you are going to have a more snug fit because of the shape of the V-shaped channel? It will no longer be C-shaped?

A. Because the bolt which is designed to go with the channel has sides that are sloped the same as the sides of the channel, it allows the bolt to locate at the junction between the sides and the lip. The prior art bolts, which have perfectly flat sides, either have to be narrower in order to locate in the channel .... You are right; when you rotate them, they move up the channel because the shape of the channel allows that to happen, but they do not go up, snug up smoothly and lock into the same place.

Q. OK, I understand. So you agree with me that they will cam up the sides of the channel, and your point is that the conical elliptical cone-shape taught in the patent, where you have effectively more bolt coming down, means that it will contact ---

A. It means that when it moves up the channel, it will go up and fit snugly into the profile of the channel. If the bolt has vertical sides, then it is narrower.

Q. I understand. So effectively what you are saying is that what we have here is a bolt that has a complimentary shape to the channel?

A. Yes, it does, absolutely right. I think I described it as a "snug fit".

A little later in his cross-examination Mr Harrison was asked about his understanding of the word “conical” and how this aspect of the teaching contributed to the purpose of the invention:

“Q. Could you have the claimant's skeleton argument, please. I do not know if it is up there with the bundle. I can read out the bit I need, paragraph 47. They say what "elliptical cone" means. What they say it means is that the shape may have flattened sloping areas in the diametrically opposed corners. Do I understand that that is what we are coming down to, that what you say is what is enough is flattened sloping areas in the corners?

A. I think what I understand is that when this bolt is rotated into position, the conical shape or the slopes on the side and the curve are such that you have intimate contact, a snug fit, within the channel profile into the corners because, in researching this and considering it further, it is fairly clear that whatever shape the cone is as you rotate it, angle will change as it goes round because it is T-shaped. It is not until the bolt is in its final position that you have got that snug fit, that intimate contact, between the sides of the head and the sides of the channel.

Q. When you say "researching" it, what do you mean?

A. I have been thinking about my second .... I have been looking more at the samples and looking at how the thing worked and considering what the patent says. It is fairly clear from looking at all the performance data that you have to have that line contact at the point when everything is assembled for it to work.

Q. If we look at Fig. 2 of the patent -- do you agree with me -- that we can read this as a skilled person would as equally having a second rounded corner diametrically opposed?

A. The shape of the head has to be such that you can put it through the mouth of the channel and rotate it to 90 degrees, so whether it has rounded corners or shaped edges, but it has to have something to allow it to rotate to 90 degrees.

Q. Therefore, on this assumption could you assume that it has a second rounded corner?

A. It would be likely to have a second rounded corner, yes.

Q. What this patent is really telling you is that you can simply angle the sides of those corners?

A. Not on the flat. On what is effectively the flat sides there they have to be sloping so that when it is at 90 degrees across the channel they snugly fit so they would be a curved corner that is sloping as it is curved in order that it can rotate.

Q. That is your understanding of the word "conical"?

A. Yes.”

Mr Alexander put to Professor Fleck the main thrust of Ancon’s argument which is that the technical purpose and effect described in the Patent is not lost if the generally elliptical cone shape illustrated in Figures 10 to 13 is truncated at a lower point so as to eliminate the elliptical shape at the top which Mr Harrison accepted is present in the illustrations of all three embodiments of the Patent. Mr Alexander put the point more succinctly in opening when he said that, in their 31/21 assembly, ACS had taken the design shown in Figures 12 and 13 and cut off more of the top.

At page 204 of the transcript there was the following exchange:-

Q. I am just concerned at the moment with purpose. Perhaps I can take one step back from this. If you look at Fig. 11, does that product have a generally elliptical base?

A. By "base" you mean 34a?

Q. Yes.

A. That is not an ellipse, no.

Q. Why is it not a truncated ellipse in that it is just an ellipse with the sides cut off?

A. It could be. It could be an ellipse with the sides cut off. It could be an ellipse with the sides cut off.

Q. The patent directs you to take something that is generally elliptical and cut the sides off, does it not?

A. Yes. It directs you to consider an elliptical cone, a generally elliptical cone, with its sides cut off.

Q. What I want to put to you is that it would be an unreasonable reading of the patent to suppose that if one were to slice the top off in the way that I have put to you in Fig. 10, that would make all the difference between infringement and non-infringement of this patent? It would be a very odd approach, would it not?

A. If I was to cut a lot of Fig. 10 all the way down to the bottom, one could argue it was either an ellipse with sides cut off or it looks like a T-headed bolt in the prior art.

There then followed a long and not terribly conclusive period of cross-examination about the properties of an elliptical cone. This included the exchange (at pages 226-227) quoted above. But it ended with one important measure of agreement which is that in the shapes illustrated in Figures 10 to 13 of the Patent the rounded corner of these was cone shaped and not cylindrical as (for example) in the Dennis patent and in some of the examples of the prior art:

“Q. We are all there the patent in contrast, if you can have that in front of you, taking up figures 10, 11, 12 and 13 does not have a generally cylindrical rounded portion, does it?

A. No, it is not cylindrical.

Q. It is a generally cone-shaped rounded portion?

A. Yes.

Q. That distinguishes it from the example that we have just been considering, does it not?

A. Yes, that is true.

Q. The advantage of the patent that is provided, is that the camming takes place at least inter alia on that surface which is both rounded and inclined towards the top of the bolt. That is right, is it not?

A. I do not believe that it is clear from the patent that the camming surface is always on the curved inclined surface. It could be at the bottom of the bolt head where it is elliptical.

Q. But the purpose of the surface being oriented in that way is at least in some orientations it can cam along that surface?

A. That is right. My understanding is that as it rotates into 90 degrees one goes to a well matched line contact in figure 10 I guess it is best seen on figure 11 when you rotate through 90 degrees the bolt head makes a line contact with the V-channel and that gives it structural stiffness and structural strength.

Q. If you go back and look at the bolt in issue in this case that we were just looking at?

A. I do not have it.

MR. ALEXANDER: Perhaps his Lordship would be good enough to hand it back to the witness.

A. Thank you.

Q. If you look at the curved end, it has a surface that is both curved and inclined toward the axis of the bolt, is it not?

A. Yes, it does.

Q. We have already established that there is camming along that surface, at least to a portion of travel?

A. Yes.

Q. And that is not the same as a cylindrical surface which would have the curve going round upright. That is correct, is it not?

A. If you had a bevelled edge meeting a circular radius you would still have a curved inclined surface and the camming trajectory might be the same as you see on this.

Q. You do not know that. The whole purpose of this is that you can reliably round that surface?

A.

The purpose of -- I do not know what the purpose of this is. The function of it is that as you rotate it, it cams first of all on the inclined surface and then picks up the base plate. That is how it cams.”

It is clear and not, I think, in dispute that the key elements of both the third embodiment of the Patent and the ACS 31/21 product is the ability of the two rounded corners to cam up the V-channel during rotation. No monopoly is claimed in respect of the V-channel as such. The invention is the creation of a shape of bolt head which, when used in conjunction with the V-channel, produces the degree of contact and camming necessary to force the head up securely against the lips and so create the benefit in terms of load capacity and lower metal volume described in paragraph [0022].

Two further matters are, I think, also common ground. The first is that the generally elliptical cone shaped head described in the Patent (in all three embodiments) does operate in this way to achieve these benefits. The second is that the ACS 31/21 bolt head (although itself not obviously elliptical in shape) achieves substantially the same benefits when deployed in a similar V channel also by a camming effect. It does so because it has two non right-angled corners which are not only rounded but also curve upwards at the corners in a way which Professor Fleck accepted was not the same as a rounded but cylindrically shaped object.

The essential question is whether the skilled addressee would have regarded the description and depiction of the bolt head as a modified version of an elliptical cone as requiring that shape to be retained and so limiting the scope of the claims accordingly. The Patent in paragraphs [0020-0021] emphasises how in the third embodiment rotation is facilitated by the rounded corners and camming is increased by the additional surface area and contact with the sides of the channel. Mr Lykiardopoulos emphasised that the Article 69 approach enables the claims to be construed by reference to the specification and drawings. Approached in this way, the question of construction, he submits, becomes easier rather than more difficult because all three embodiments described in the specification include the oval elliptical top as a feature of the bolt head and so achieve the snug fit which Mr Harrison said was the aim of the adopted shape. The elliptical cone best achieves these results. It is not, as he put it, some strange redundant feature.

In response to Mr Alexander’s suggestion that ACS has attempted to avoid infringement by simply further truncating the cone shape so as to obliterate the oval form, he says that there is no teaching in the Patent to suggest further truncation or the omission of the oval shape. In fact it is retained throughout the three embodiments of the Patent.

Against this, Mr Alexander stresses the need to avoid an unduly mathematical or perhaps geometrical approach to the wording of the Patent. He relies on the requirement in the Patent for there to be a curved sloping surface (a cone) in contrast to the curved but vertical surface of a cylinder. Perfect ellipses (as Professor Fleck accepted) are rare in engineering and the Patent should be regarded as stipulating for a bolt head shaped to have two conical corners in balance with each other to provide the optimum camming effect within the V-shaped channel. As he put to Professor Fleck, it would be odd, he submits, for the patentee to be denied protection in respect of a design which utilises that teaching in respect of the shape of two of its quarters but avoids an ellipse by truncating the head to below the point at which the elliptical shape at the top can be maintained.

In relation to Mr Lykiardopoulos’s point that to construe the Patent without reference to an elliptical shape would produce uncertainty for third parties in terms of what protection the Patent affords, Mr Alexander says that there is a clear distinction between a curved straight surface disclosed in some of the prior art and a generally elliptical cone shape. It would not be fair protection for Ancon to be deprived of the benefit of its patent by a product which takes the substantial benefits of the invention.

The phrase “generally elliptical cone shape” is used by the patentee as a description for all three embodiments of the Patent and applies to each of the relevant claims. The head illustrated in Figure 6 (33) is described in claim 1 as a generally elliptical cone shape and it is this head which features in claims 1, 3, 6 and 7. Claims 8 to 13, which include the second and third embodiments, are variants of “the cone shape” which has to be read as a reference back to its description in claim 7. It is apparent from those claims (and, indeed, from paragraphs [0020-0021] of the specification) that much of the emphasis is on the ability of the rounded sides 35r to contact with the walls of the V-channel to rotate the fixing head and produce the camming necessary to force the head against the lips of the channel. But this is written and has to be read against an acceptance that the elliptical cone shape of the head achieves these results. Ancon’s case is that these features attract the description of “generally elliptical cone shaped” almost regardless of what shape the bolt head takes and even where (as in this case) the degree of truncation is such as to obliterate the ellipse entirely provided that the essentially conical shape of the corners is maintained. Mr Alexander in closing said that this was what the Patent is primarily concerned with when it talks of a generally elliptical cone shape. Its recognition that the elliptical cone of the first embodiment will still function according to the teaching if it has flattened sides and a truncating top merely go to emphasise that the oval or elliptical top is not the critical factor in engineering terms. He submitted that there is nothing in the teaching of the Patent that regards the precise shape of the top surface as of any technical importance for the purpose of the invention. The relevant surfaces are those against which camming takes place: i.e. 35r on Figures 12 and 13; and it is these surfaces which need to embody the “generally elliptical cone shape” to have this effect.

Attractive as this argument is, I am unable to accept it. Everyone agrees that the elliptical cone in its various forms illustrated in the Patent does have the ability to cam in the way taught and to produce the advantages specified when used in conjunction with the V-shaped channel. But it does not follow from this that one can construe the claims as covering any manufactured fixing that is capable of producing the same effect regardless of whether, as a matter of ordinary language, it can be described as a “generally elliptical cone”.

The difficulty I have with Mr Alexander’s approach is that it gives no real recognition to the patentee’s reference in the claims to the bolt head being elliptical. It is clear from the specification that in the first embodiment the shape of the head is an elliptical cone without qualification (see paragraph [0011]). The word “generally” comes into use when one gets to the second and third embodiments which introduce a degree of truncation; flattened side areas; and two right-angled corners. Although these modifications do not eliminate the elliptical shaped head of the fixing, they do compromise it in geometrical terms and give rise in the text of the specification to the use of the word “generally”. It is, however, clear from this that the phrase “generally elliptical cone shape” is used to describe shapes, all of which retain the essential feature of an ellipse. In the context of the specification as a whole, it can have no other meaning. Although construction is a matter for me, it is not without significance that Mr Harrison was clear in his evidence that what the Patent was teaching the skilled addressee was that some form of elliptical head was required.

The real question, therefore, is not what this phrase means but whether its inclusion in the claims determines their scope. It seems to me that it clearly does. There is nothing in claim 1 which allows the addressee to assume that the claim is not limited to what constitutes a “generally elliptical cone shape”. Nor does Mr Alexander put his case differently. Ancon’s argument is that one should construe the phrase more widely but this carries with it the acceptance that the narrower view of construction determines the limits of the monopoly.

The argument that this leaves it open to a third party to take the benefit of the invention by using a differently shaped head is a familiar one. But the answer to it is that it is for the patentee to specify the limits to his claims. It is important to bear in mind that the patentee may have a number of reasons for limiting the scope of the claims which are not always evident to a subsequent reader. As Lord Hoffmann said in Kirin-Amgen, the patent may, for one reason or another, claim less than it teaches or enables.

I, therefore, prefer the construction of the claims advanced by ACS which, for the reasons I have given, does in my view respect Article 69 and the Protocol. I am conscious that my decision is in conflict with that of the EPO on application No. 96 942 518.0 who construed “generally elliptical” as including any rounded non-circular form. But there is nothing in their reasoning which causes me to take a different view.

It is, I believe, common ground that the ACS fixing in its 31/21 assembly is not a generally elliptical cone shape. Mr Harrison accepted as such in cross-examination and the computer modelling carried out by Ancon has not convinced me otherwise. It follows that the case on infringement is not made out. It is not, therefore, necessary for me to express any view about the arguments on the secondary issue of the meaning of “forced against the lips”.

Given my construction of the claims, I can deal with this quite shortly.

ACS does not suggest that the Patent lacks novelty and its case on insufficiency falls away on the basis of my construction of the term “generally elliptical cone”.

Dennis is relied on to support a case on anticipation and obviousness. It is a 1957 patent which Mr Alexander described as a method for fixing shelves. In fact the specification suggests a wider use than that, although not one involving heavy duty fixings of the kind described in the Patent. The specification includes a V-shaped channel (which was later incorporated into the Patent) into which a nut is placed which is then threaded on to a bolt through the space between the lips. It is said that its disclosure anticipates claim 1 because the claims of the Patent are wide enough to cover the more lightweight system used in Dennis. It is also said to anticipate the generally elliptical cone shape of claim 1 if this is to be construed as including shapes which are not elliptical. This is because Dennis teaches (on page 2) that the nut which is placed into the channel has one or two chamfered or rounded-off corners to enable it to fit.

ACS accepts that Dennis does not disclose an identifiable elliptical shape and therefore, on my construction of the Patent, that rules out any suggested anticipation. I should add that, even on Ancon’s construction of “generally elliptical cone shape”, I would have reached the same conclusion. None of the prior art, including Dennis, has anything but a cylindrically rounded section. Dennis does not teach the use of a conical face which, on Ancon’s case, is the key feature to the Patent. This was also the view of the EPO in its ruling already referred to. At paragraph 5.4.1 it said this of Dennis:-

“5.4.1

Document D2 on its own does not give a hint to the features in the characterising part of Claim 1. The head of the fixing used with the known channel assembly is in the form of a threaded nut, an angularly dimension of that nut being greater than the spacing of the inclined walls of the channel, such that the fixing is locked when the nut is rotated (see page 1, lines 58 to 74 and fig. 2). One or both corners of the nut at the ends of the opposite diagonal are chamfered or rounded off, so the nut can be positioned with respect to the channel, and the end regions of the lower face of the nut are upwardly inclined (page 2, lines 59 to 82). It is clear from D2 that a nut with flat surfaces is used, and the advantage of a conical shape of the head of the fixing is not disclosed in D2.”

The other claim of anticipation based on Dennis is in relation to claims 3 and 6 which incorporate the camming effect of the design and the head being forced against the lips of the channel. Anticipation is claimed on the basis that the nut shown in Dennis would, on rotation, cam up against the side walls and so replicate the additional element in the claims. But ACS accepts that claims 3 and 6 are for a channel assembly using the generally elliptical cone shaped head which, on my construction, is not anticipated by Dennis and the attack on claims 3 and 6 therefore fails for the same reason.

There is little to add on obviousness. As Ancon points out, it is difficult to treat Dennis as a realistic starting point for the designer of a fixing of the kind illustrated in the Patent given that it was nearly 40 years before the V-shaped channel was picked up and adapted for use as a channel assembly of the kind in issue in this case. That apart, the purpose of the channel is to provide a place for the nut to rest prior to receiving the threaded nut and there is no disclosure in Dennis of any camming effect. There is nothing in this patent to make the use of a bolt head of the kind described in the Patent as an obvious step to take in order to achieve the benefits it produces.

Kohler is no longer relied on as prior art which leaves Sandwith.

Sandwith is a patent relating to what is described as a concrete form system component comprising interlocking novel channel form beams and T bolt connections. It is a completely different system in appearance from the Patent in suit or from Dennis and does not incorporate V form channels of the same kind. Ancon’s case is that there is nothing in Sandwith to suggest the use of a generally elliptical cone shaped head. On my construction of these words, Mr Lykiardopoulos accepts that. The attack on validity, therefore, fails.