Factual and Procedural Background
This appeal concerns the validity of a patent held by the Appellant, Company A, relating to disc brake calipers for motor vehicles, particularly racing cars. The patent was revoked by HHJ Birss QC in the Patents County Court on the ground that claim 1 contained added matter, which is impermissible under patent law. Other grounds such as insufficiency and obviousness were rejected by the trial judge. The Respondent, Company B, also challenged one of the judge's findings on obviousness by way of a respondent's notice. Permission to appeal was granted on the added matter issue. The patent relates to a caliper body comprising peripheral stiffening bands ("PSBs") that are asymmetric about a lateral axis. The dispute focuses on whether this feature was clearly and unambiguously disclosed in the original patent application or whether it constitutes impermissible added matter.
Legal Issues Presented
- Whether the granted patent contains added matter by including a feature of asymmetric peripheral stiffening bands not disclosed in the application as filed.
- Whether the claim to asymmetric PSBs represents an impermissible intermediate generalisation beyond the specific embodiments disclosed.
- Whether the patent is invalid for obviousness in light of prior art, particularly the Baba document.
Arguments of the Parties
Appellant's Arguments
- The application clearly and unambiguously discloses asymmetric peripheral stiffening bands as claimed.
- Even if the disclosure is limited to a class of hockey stick shaped PSBs, the granted patent does not add matter by generalising to all asymmetric PSBs.
Respondent's Arguments
- The judge was correct in finding that the granted patent claims an impermissible intermediate generalisation, claiming a broader class of asymmetric PSBs than disclosed.
- The PSBs were only disclosed in combination with material-saving features elsewhere in the caliper body, and claiming them independently adds new matter.
- On obviousness, the prior art Baba discloses asymmetric elements and the skilled person would have been motivated to modify it to include two cylinders, making the patent obvious.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Bonzel v Intervention (No 3) [1991] RPC 553 |
Test for added matter: strict comparison between application as filed and granted patent, requiring clear and unambiguous disclosure. |
Used to frame the threefold task of ascertaining disclosure in the application and patent and comparing for added matter. |
| Richardson Vick's Patent [1995] RPC 568 |
Whether the skilled person learns anything new from the amended specification compared to the unamended one. |
Adopted as the fundamental test for added matter. |
| Vector Corporation v Glatt Air Techniques Ltd [2007] EWCA Civ 805; [2008] RPC 10 |
Policy behind the added matter rule and examples of impermissible claim amendments adding new combinations. |
Distinguished on facts; no undisclosed combination in the present case unlike Vector v Glatt. |
| Texas Iron Works Inc's Patent [2000] RPC 207 |
Claims may generalise beyond specific embodiments without adding matter if no new technical information is disclosed. |
Applied to conclude that the claim's generalisation to asymmetric PSBs does not add new technical information. |
| A.C. Edwards Ltd v Acme Signs & Displays Ltd [1992] RPC 131 |
Generalisation in claims does not necessarily add matter if specification and claims read together disclose the invention. |
Supported the view that claims can describe features in more general terms than embodiments without adding matter. |
| Palmaz's European Patents (UK) [1999] RPC 47 |
Intermediate generalisation can add matter if a feature is taken out of context and its significance is not disclosed. |
Considered but distinguished; here the technical significance of the PSB configuration was clearly disclosed. |
| Decision T 065/03 Toyota Jidosha KK (EPO Technical Board of Appeal) |
Replacing specific claim terms with broader terms can add matter if it discloses new technical information. |
Used to illustrate that generalisation is impermissible if it introduces new information, which was not the case here. |
| Windsurfing v Tabur Marine [1985] RPC 59; Pozzoli v BDMO [2007] EWCA Civ 588; Conor v Angiotech [2008] UKHL 49 |
Framework for assessing obviousness including identification of skilled person, inventive concept, differences from prior art, and whether differences are obvious. |
Applied in the obviousness analysis regarding the prior art and inventive concept of the patent. |
Court's Reasoning and Analysis
The court began by outlining the legal framework for added matter under section 72(1)(d) of the Patents Act 1977 and the corresponding European Patent Convention provision. It emphasized the strict comparison between the application as filed and the granted patent, requiring that no new information be disclosed to the skilled person by the amendment.
The court analysed the application’s disclosure of the peripheral stiffening bands ("PSBs"), noting that the application described PSBs extending around the leading or trailing ends of the caliper limbs, necessarily resulting in asymmetry about the lateral axis. The court found this disclosure clear and unambiguous as a class of asymmetric PSBs, exemplified by "hockey stick" shaped embodiments.
The trial judge had concluded that the patent claim to asymmetric PSBs was an impermissible intermediate generalisation, claiming all asymmetric PSBs rather than just the specific embodiments. The court rejected this, holding that the claims, when read with the specification, did not disclose any new technical information beyond the application as filed.
The court drew on authorities establishing that claims may generalise features without adding matter, provided no new technical information is introduced. It distinguished the present case from cases where impermissible intermediate generalisations were found, such as Palmaz and Vector v Glatt, because here the technical significance of the PSB configuration was clearly disclosed.
Regarding obviousness, the court accepted the trial judge’s construction of "peripheral stiffening band" as a band of material appreciably beyond the limb material at the ends of cylinders, intended to stiffen the caliper. The court examined the prior art document Baba, concluding that it did not disclose PSBs as claimed. The judge’s findings that Baba’s features were not peripheral stiffening bands and that the skilled person would revert to a symmetrical design if modifying Baba were upheld.
Consequently, the court found no basis to overturn the trial judge’s conclusions on obviousness and no added matter in the patent claims.
Holding and Implications
The court ALLOWED THE APPEAL and set aside the order revoking the patent. The patent was held not to contain impermissible added matter and was not invalid for obviousness on the grounds pursued.
The direct consequence is that the patent remains valid and enforceable against the Respondent. No new legal precedent was established beyond the application of existing principles to the facts of this case.