Disk brakes, hockey sticks and added matter

Author: Paul England (Taylor Wessing LLP)

AP Racing Ltd v Alcon Components [2014] EWCA Civ 40, Court of Appeal, England and Wales, 28 January 2014

Journal of Intellectual Property Law & Practice (2014) doi: 10.1093/jiplp/jpu052, first published online: April 25, 2014

The Court of Appeal has overturned the first instance decision to hold that a disk brake caliper patent does not disclose added matter.

Legal context

The rule on added matter, as summarized by the Court of Appeal in AP Racing Ltd v Alcon Components, is ‘the rule that a patent application or patent may not be amended in such a way that it contains subject matter which extends beyond the content of the application as filed. If it has been so amended, and the added matter is not or cannot be removed, the patent will be invalid.’ A particular issue when assessing whether there has been added matter in a granted patent specification, is the relationship between the breadth of the granted claim, and what is disclosed in both the specification of the granted patent and its corresponding application.


In AP Racing, the patent application and granted patent in question are for disk brake calipers used in motor vehicles, and particularly the asymmetrical peripheral stiffening bands (PSBs) associated with the caliper body embodied in the application as having a ‘J’ or hockey stick shape. The granted patent contains materially the same disclosure as the application, but the following feature of claim 1 of the granted patent is not disclosed in the application ‘in which each of the stiffening bands has a profile that is asymmetric about a lateral axis of the body when viewed in plan’.

This feature of the claim gave rise to two points of dispute:

* Is there a clear and ambiguous disclosure in the application of PSBs asymmetric about the lateral axis of the caliper body?

* Nonetheless, if only a class of generally hockey stick shaped PSBs is disclosed in the application, does the claimed feature contain added matter?


On issue 1, the Court of Appeal has held that, although not expressly stated in the application, it would be abundantly clear to the skilled reader that the PSBs were, individually, asymmetric about a lateral axis of the caliper body, and the presence of the PSBs had the effect of giving the overall shape of the caliper body an asymmetric appearance.

Answering issue 2, the Court of Appeal says, depends on whether it is legitimate to add to a claim features that describe the invention in more general terms than a specific embodiment. Summarizing authorities from the English courts and the European Patent Office's Technical Boards of Appeal, the Court of Appeal concludes that it is clear that the law ‘does not prohibit the addition of claim features which state in more general terms that which is described in the specification’.

In this case, the application would be understood by the skilled person as disclosing that the asymmetrical design of the PSBs is significant in imparting stiffness to the caliper, and that the hockey-stick shaped PSBs are ‘necessarily asymmetrical’. It must then be asked whether any disclosure has been added to this in the granted specification. The description of the PSBs in claim 1 as ‘asymmetric’ has to be read as part of that disclosure. From this, the skilled person would understand that the claim covers asymmetric PSBs generally. The skilled person would also understand that the PSBs are exemplified by the hockey-stick shapes described in the specific embodiments. The skilled person would not, therefore, learn any new information about the invention from the granted patent.

Practical significance

The Court of Appeal appears to say in A P Racing that the skilled person would understand the breadth of the claim in question to be supported by a coextensively broad disclosure in the application. Although the Court of Appeal does not say so, the case invites comparison with sufficiency cases in which the principle of an inventive concept derived from the specification can have a general application across a claim.

No comments:

Post a Comment