A Ward Attachments v Fabcon Engineering Ltd – “Buzz” test for obviousness and acquiescence based on failure to respond to defendant’s letter

Judgment 29th July 2021

This was a patent infringement case in IPEC which concerned apparatus for receiving freight containers from the bed of a truck.

A picture containing text, sky, outdoor, trailer Description automatically generated

Infringement and validity were in issue. On validity, it was claimed that the Patents were invalid for obviousness over two pieces of prior art, invalid for insufficiency and the divisional patent was invalid for added matter over the parent patent. Also, the defendant claimed that the claimant should not obtain any relief on the basis of acquiescence. Of interest, is that the judge found it helpful, when considering inventive step to ask what it was about an invention that gives an expert in the relevant field a “buzz”.

The judge also considered a defence of acquiescence based upon a failure of a patentee to reply to a letter from a defendant that its product did not infringe and that that if it had not heard from the patentee within 14 days, it would consider the matter “to be closed” The judge pointed out that in such circumstances, the defendant must show that it acted in a mistaken belief as to its rights and the patentee failed to assert its rights even though the patentee knew both of the defendant’s belief and the true position. The court dismissed the defence on the grounds that defendant had not satisfied the court that the claimant knew of its belief.  However, it illustrates the desirability of patentees responding to letters claiming non-infringement.

The court thus found the patent was infringed and that the patent was valid.

Richard Davis acted for the successful claimant.

A report of the judgment can be found here