Confusion about generally elliptical cone shapes

The IPKat thought he knew all there was worth knowing about what would be classified as being of a "generally elliptical cone shape", when he read the judgment of Mr Justice Patten in Ancon Ltd v ACS Stainless Steel Fixings Ltd back in October 2008 (IPKat commentary here). How wrong he was. After Patten J decided that Ancon's patent, although valid, was not infringed because ACS's product did not include a head having a generally elliptical cone shape, Ancon decided to appeal. They now have the result they originally wanted, thanks to a judgment delivered by Lord Justice Jacob yesterday.

The judgment, although unusual, could have been very unusual indeed had the other judge involved, Lord Justice Waller, not agreed with Jacob LJ, because the usual third member of the Court of Appeal was not present due to illness. The parties were willing to accept the risks of having a hung decision, which appears to have paid off for Ancon at least.

What puzzles and troubles the IPKat, however, is the highly unusual, not to say bizarre, way in which Jacob LJ decided to interpret the wording of claim 1 of the patent in question, which reads:
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. [IPKat emphasis applied]
One of the embodiments in the patent (see illustration, above right) showed what this would mean in practice. The head, shaped to fit a matching channel, was of an elliptical shape to allow it to lock into the channel when turned, and was cone-shaped to allow it to more closely fit the channel. This combination had the effect of improving engagement between the two parts, which together served as a secure mounting assembly for hanging heavy things from.

As all European patent attorneys will immediately recognise, the positioning of the characterising clause in the claim clearly indicates that the generally elliptical cone shape of the head was also what persuaded the EPO that the claimed invention was distinguished over the closest prior art document, which was identified during opposition proceedings as GB782428. This characterising feature should be reasonably clear from the selection of figures from this document shown on the left.

What the IPKat fails to understand is how, given all this, the term "generally elliptically cone shape" could be applied to the alleged infringing article (pictured below right). The IPKat's own conclusion would most definitely be that it would be stretching the bounds of credulity quite a bit to imagine that such a shape could be described as being in any way a generally elliptical cone. He wonders therefore whether Jacob LJ has indulged a bit too much in the "meticulous verbal analysis" that, quoting Lord Diplock in Catnic, he specifically warns against (paragraph 19). If the alleged infringement could be described as being generally elliptically cone-shaped, then why would the corresponding component in the closest prior art document not be described as such? Is the IPKat missing something obvious here, or is this a judgment that is just plain wrong?

Merpel simply wonders what it is about building products that makes such contentious legal decisions.
Confusion about generally elliptical cone shapes Confusion about generally elliptical cone shapes Reviewed by David Pearce on Wednesday, June 17, 2009 Rating: 5


  1. As to "generally cylindrical" v "conical", see Conoco Specialty Products (Inc.) v. Merpro Montassa Ltd. [FN1] [1994] F.S.R. 99 (which gave a pretty narrow construction) - but I suppose a Scottish decision is not binding on the Patents Court.

    Ancon is not the last word on the matter - in Corevalve Inc v. Edwards Lifesciences AG, Edwards Lifesciences Pvt, [2009] EWHC 6 (Pat) Ch D the claim required "cylindrical" and was held to mean "generally cylindrical". Westlaw brings up some 29 decisions on "generally cylindrical", in fact. Amazing.

  2. I wonder why the defendant didn't appeal on validity. Given the apparent similarity of the alleged infringement to the prior art, a squeeze argument seems to suggest itself.

    What doesn't seem to have featured is the fact that the prior art document states that the chamfered bits 10 in Fig. 2 could be rounded off. If that were done, isn't the nut 7 exactly the same shape as the one in the picture? They both seem to have a rectangular top surface, a smaller rectangular bottom surface and inclined surfaces joining top and bottom at the shorter ends, with the corners at the ends of one diagonal rounded off.

    Doesn't this fall within "any rounded non-circular cross-section" as approved in para 28 of the judgement?

    I also question all the emphasis on camming. Claim 1 is not limited to camming. I don't know if the alleged infringement does exhibit camming, but if it does, perhaps we have got what should have been the right result.

    What seems to have happened here is that the case was drafted without knowledge of the prior art. The patentee presumed that inclined side walls were new and claimed that because it made the device stronger than upright walls and with less material. All the arguments about the camming contributing to the strength in tension may well be a smokescreen - I would guess that the strength is mainly to do with the lips being relatively shorter than the design with upright walls and the head relatively thicker, essentially the same geometry being shown in the citation.

    However, there could be some advantage in the vertical camming - reduced movement and better resistance to compressive loads, perhaps - and this doesn't seem to be taught by the prior art.

    So I reckon there could have been a claim reciting the head having inclined sides which are shaped so as to engage the channel side walls and cause a camming action on rotation, to urge the head towards the lips (claims 1+2+4 as granted). Such a claim might be valid and infringed.

    Sounds like a P6 answer.

    PS - of course such a functional claim would be objected to by many less experienced EPO Examiners who don't seem to have been taught that the requirement for clarity means that the reader can immediately determine whether any possible alleged infringement falls within the claim or not. The Guidelines say you can have functional claims only if the invention can't be defined by structural features. So they'll try and insist on whatever the description mentions, such as the wonderfully clear "generally elliptical cone shape"...

  3. To me the primary characteristic of an ellipse is its smooth curvature.

    The allegedly infringing article has two (near-enough) squared-off "corners" to be sure, but the other "corners", if I can call them that, are clearly smoothly curved.

    However, looking at the prior art document, what is shown there is decidedly angular.

    The allegedly infringing article is this IMO of quite a different nature in terms of ellipticity viz a viz the prior art. It posseses at some curves.

    Whether it is elliptical enough to qualify as "generally elliptical(ly cone shaped)" is another story, but I don't see a huge problem here.

    Cheers, Luke

  4. In my view, the judges simply concluded that the defendants were taking the pith (and marrow).

  5. was a Gillette defence put forward by the alleged infringer? seems rather obvious (excuse the pun) to me that such an argument should have been used.

    Will this case be referred to their Lordships??

  6. Interesting to note at para 28 "In the result I agree with the Opposition Division of the European Patent Office"
    This seems like a pragmatic decision, Jacob clearly thinks the concept was taken and was generous to the draftsman too.
    By the way, there are better ways of fixing embedments

  7. Reminds me of Edbro v Saphem on tipping trucks. Not high tech at all. To the Appeal Court fell the task of construing "slide", and the Defendant had elected not to put validity in issue. The French patent owner had spent serious money on a beautiful model truck, fun to play with, which during the appeal Hearing was on the bench in front of the Chairman. English Defendants had built a rather large and ungainly wooden model, which lay elsewhere in the courtroom, and interested their Lordships not at all. Who knows what would have happened, had there been a counter-claim for invalidity, and a better model.

  8. My take of this decision is that the infringing product looks somewhat similar to the arrangement of Fig. 13. Construing the claim to include the Fig. 13 arrangement within the scope of protection leads to the conclusion that the patent is infringed.

  9. I think Jacob LJ’s decision was entirely right. The function of the sloped sides (the “conical” part) is to engage with the sloped sides of the channel. The function of the varying radius (“elliptical”) is to operate as a cam. The sides of the infringing device are sufficiently sloped and sufficiently varying in radius to do both these things. The only think that makes it even seem non-conical is that it is truncated. But as Jacob LJ said, “The shape of the top of the bolt, which does not come into contact with the channel is immaterial to this,” so truncating the cone does not affect the function. And it is clear that the patentee intended a truncated cone to fall within the claims - all the cross-sectional drawings illustrated truncated cones. So I think it is clear that “cone-shape” is properly construed to include a truncated cone. After that, it is simply a matter of degree. The defendant truncated the cone more severely than those illustrated in the patent, but it is still a functionally a truncated cone. Perhaps it doesn’t look like “a cone,” but to me it looks very much like a severely truncated cone. The truncation clearly doesn’t take it outside the claims and I don’t think the degree of truncation should either.


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