Unilin Beheer BV v Berry Floor NV & Ors

A patent claim must be construed purposively through the eyes of the skilled person reading the specification as a whole. Language requiring a connection to be “free of play” may permit trivial movement which makes no practical difference. The possibility of difficult borderline cases does not require an absolute construction.

A patent claim receives priority only where the skilled person can derive its subject matter directly and unambiguously, using common general knowledge, from the priority application as a whole, and the disclosure enables the invention. The claims or consistory clause in the priority application are relevant but not determinative. Where several features are disclosed together, whether each is also disclosed independently depends on the substance of the technical teaching.

Unilin Beheer BV owned a European patent concerning mechanically interlocking hard-floor panels. The Patents County Court held the patent valid and infringed by flooring manufactured or imported by Berry Floor NV and Information Management Consultancy Design Ltd, and sold by B&Q plc.

The defendants appealed on three issues: the construction of “free of play” in the proposed amended claim; infringement by the principal category of accused flooring; and the claim's entitlement to the first claimed priority date. Loss of priority would expose the claim to Unilin's intervening publication and require further limitations which would exclude most of the accused products.

1. The appeal was dismissed unanimously. The judge's construction of “free of play” was varied, but his conclusions on infringement, priority and validity were upheld.

2. “Free of play” meant free of play for practical purposes, rather than the absolute absence of any possible horizontal movement. The skilled person would understand the patent as excluding gaps within the joint that mattered in practice. The claim contained no requirement that the connection remain perfect for a reasonable period. The possibility that difficult questions of fact and degree might arise at the boundary did not justify an absolute construction.

3. On that construction, all the accused products infringed. The defendants' advertising described their connections as seamless, tightly butted and without gaps. The evidence also established that the manufacturing tolerance would not produce a visible gap in a properly laid floor. It was unnecessary to decide whether infringement would also have been established under the defendants' stricter construction.

4. Under article 87(1) of the European Patent Convention, the question was whether the skilled person could derive the claim's subject matter directly and unambiguously, using common general knowledge, from the priority application as a whole. The disclosure also had to enable the claimed invention. The inquiry concerned technical disclosure and was not formulaic.

5. The claims and consistory clause in a priority application were parts of its disclosure but were not determinative. The application had to be read as a whole. This approach was consistent with article 4H of the Paris Convention, which permits relevant elements to be disclosed outside the claims.

6. The priority application independently disclosed the use of MDF or HDF to make a snap-fit connection free of play. The lip-length and minimum-thickness features supplied separate advantages and did not contribute to achieving the free-of-play connection. The proposed amended claim was therefore entitled to the first priority date and remained valid.

1. Court of Appeal (Civil Division): By judgment reported as [2004] EWCA Civ 1021, dismissed the defendants' appeals. It varied the construction adopted below but upheld the findings of infringement, priority and validity.
2. Patents County Court: His Honour Judge Fysh QC held that the patent was valid and infringed by both categories of accused flooring.