Triumph Actuation Systems LLC v Aeroquip-Vickers Ltd & Anor

In a patent amendment application, added matter under section 76(3)(a) of the Patents Act 1977 is assessed by comparing the proposed amendment with the application as filed. Matter deliberately removed during prosecution may therefore be reintroduced if it was disclosed in the application as filed, although the claimed combination must itself be directly and unambiguously disclosed. Patent validity must be assessed by considering the inventive concept as a whole. It is impermissible to dissect a mechanical invention into old or obvious components and infer obviousness from that analysis alone. A claim may nevertheless be obvious where the prior art and common general knowledge make the claimed combination an obvious implementation.

The claimant sought to amend a granted patent for a reversible hydraulic power transfer unit used between two aircraft hydraulic systems. The defendants opposed the amendment under section 76 of the Patents Act 1977 and challenged the proposed claim for lack of novelty and obviousness. The claimant also alleged infringement of the proposed amended claim.

The court considered whether the amended combination was disclosed in the application as filed, whether the alleged devices infringed the proposed claims, and whether the proposed claim was invalid for obviousness in light of a Vickers lecture and common general knowledge.

1. Infringement. The alleged device fell within proposed amended claim 1. The claim did not require springs associated with the variable-volume chambers to centre the swashplate. The pressure-responsive means could be arranged non-coaxially, and the alleged device satisfied that requirement through a long plunger, hydraulic connection and seals. Claim 2 was not infringed because “rest position” meant the position determined by the actuator springs when no pressure was applied, not a range of positions produced by positional feedback.
2. Allowability of amendment. Section 76(3)(a) required comparison with the application as filed, rather than merely with the specification immediately before amendment. The combination sought to be introduced, however, was not distinctly disclosed in the application as filed. The features of old claim 6 were described in conjunction with the disclosed spring-biased jack and were not disclosed as a free-standing control arrangement applicable to a different actuator using positional feedback. The amendment was therefore refused.
3. Validity. The proposed amended claim would also have been invalid for obviousness if allowed. The proper approach was the four-stage analysis in Windsurfing International v Tabur Marine [1985] RPC 59: identify the inventive concept, identify the skilled person and common general knowledge, identify the differences from the prior art, and ask whether those differences required invention. The court warned against hindsight and dissecting a single machine into component parts merely because each component was known. On the evidence, the proposed claim was nevertheless obvious in the light of the Vickers lecture and common general knowledge.
4. The patent was invalid because the patentee did not defend the existing claims and the proposed amendment was refused. If made, the proposed claim would also have been invalid for obviousness.