SEB v De'Longhi Appeal

Originally published July 2003

This was an appeal made by the appellant/patentee SEB against the finding of the judge that the patent, which concerned so called "cool - wall" fryers, was obvious over common general knowledge. Peter Gibson LJ, giving the unanimous decision of the Court of Appeal, upheld the decision of Pumfrey J.

De'Longhi, the defendants/respondents, cross-appealed [1] the findings on infringement and insufficiency, which Pumfrey J had made in favour of SEB. On these issues as well, Pumfrey J was upheld.

Infringement and Insufficiency

As is commonly the case, infringement was tied up with construction. The main issue for the Court had been what the word "closed" meant in context of the claims. Once the Court had decided "closed" did not require a hermetic seal, the fact that the defendants' fryers had tiny gaps between the two components concerned did not mean they did not fall within the claims. The consequent finding of infringement was upheld, without the need for a "Protocol question" type analysis concerning material variants.

Insufficiency was run as a squeeze with infringement by De'Longhi , but as the judge had no difficulty in deciding what "closed" meant, it followed that the insufficiency argument could not succeed. The Court of Appeal agreed.

Obviousness

Findings of obviousness over common general knowledge, ("cgk"), alone are less common than over citations of particular pieces of prior art, which usually take the form of earlier publications. In the latter case, cgk is the starting point from which the skilled man considers the particular publication. In the former, as in this litigation, it is both starting point and particular prior art simultaneously.

Here, both experts gave evidence on what they considered to be the common general knowledge. There were differences of opinion, one of the main ones being the extent to which the skilled man at the priority date would "compartmentalise" his knowledge of differing household appliances, which might typically be made by the same company.

That was not the only factor in resolving this issue though. De'Longhi's expert had been found by the judge to be of an inventive turn of mind - to what extent had the judge borne this in mind when weighing up his evidence?

In the appeal, both parties relied on the familiar cases [2], which warn against step by step ex post facto analysis - a particular danger where a finding of obviousness arises from combining elements within...