LB Europe Ltd v Smurfit Bag In Box SA

This appeal involves no question of general importance and is unlikely to be of interest to anyone but the parties. The principles of the construction of patent claims are settled and quoted by the Deputy Judge at [51] of his judgment [2007] EWHC 510 (Pat). Neither side suggests he got these wrong.

In these circumstances I do not propose to set out much of the background -- it may be found in the judgment below. And I shall, where possible, cross-reference to it rather than set the material out here again. The issue is whether Du Pont’s Liqui-Save (“LS”) product falls within the scope of the claims of Smurfit’s European Patent (UK) 432,070.

The judge held the patent valid but not infringed. The appeal is confined to the single issue upon which he found non-infringement. This issue is whether the LS falls within elements (a)-(p) of Claim 1, set out by the judge at [7] The respondents contend that, if the judge is wrong about that, he wrongly held that other parts of the claim were satisfied. In the event it has not been necessary to get as far as those contentions. The respondents do not challenge the finding of validity.

Both parts of the claim upon which the judge found non-infringement are concerned with the “engagement means for fixation in the plug of the container”. The general purpose is simple and self-evident: you want to be able to push the tap into the plug and be unable to pull it out once it is in.

First some terminology: the tap has what might be called the barrel. This fits into what the patent calls a plug. The language is a bit topsy-turvy -- ordinary people normally speak of a plug fitting into a plug hole. Here, the so-called “plug” is the plug hole. The plug is glued by its large flange to the box of wine. When the tap is inserted you cannot separate anything and the result is the box is secure.

Fig. 1 of the patent shows the specific embodiment contemplated by the patentee. The tap has a wide groove 7. The plug is hardly shown at all but we do know there is meant to be an annual projection on the inside of it. One can see some dotted lines dropping into the wide groove 7. It angles from the tap side into the bottom of the groove. The idea is the barrel is pushed past the projection, the projection elastically drops into the wide groove and is locked there, and cannot be pulled out because the projection has a barb-like shape. The language describing this is short and not particularly well-drafted. It spans pp.5 to 6 of the translation of the patent.

Although Mr Silverleaf took us through the passage, in the end I do not think one gets much assistance one way or the other. He suggested that Mr Alexander, in his skeleton argument, has misread the teaching there but I do not think he did at all.

The engagement means of the LS works in the way illustrated at paragraph 65 of the judgment. The inner end of the plug has a cut-away wider portion. The whole of the plug is ever so slightly tapered. Mr Silverleaf told us the difference was 0.1 mm between one end and the other. The barrel of the tap has a series of ribs. When you push the barrel in you can feel it getting tighter the further you push it in. Elastic deformation takes place. When the last rib portion passes into the cut-away portion the plastic material springs back and the barrel is held in.

Does this fall within the words of the claim? The judge said no. The key part of his judgment was where he said that there was no projection on the inside surface of the plug. That is what is called for by integer (m) of the patent.

Mr Silverleaf says that is wrong. He submits that, technically speaking, the ever-so-slightly conical inside of the plug amounts to a projection running from one end to the other. He says that, mechanically, it does exactly the same job as is contemplated by the patentee: that is to say as you push in, the conical projection is deformed and then snaps out into the wide groove, which he says is to be found on the barrel of the tap.

The point is extremely short: can one really, strictly and fairly regard the mere fact that there is a conical inside to the plug, as enough to constitute a projection? To my mind the answer is clearly no. It is not suggested that the word has any technical meaning; it is a matter for construction for the court. Mr Silverleaf ingeniously says: “Well, start off with what is shown in the drawing of the patent, and imagine that, instead of having a short bit as is shown, the dotted line, instead it was gradually lengthened out. When would it stop being a projection?”. That is always a clever way of putting the point: “how many grains of sand make a pile, how many make a desert?” One does not have to answer such a question. Here there comes a point when there is no projection. The inside surface of the plug of this device has not got one.

For that simple reason, the device does not fall within the claim and I will dismiss this appeal.

I agree.

So do I.