A while back, I criticized the Federal Circuit for seemingly going out of its way to find implied, narrowing limitations in otherwise broad claims. While it’s too early to break out the champagne, the Court’s decision last week in Anheuser-Busch v. Crown Cork & Seal suggests that common sense and plain English still play some role in the dark and mysterious art of construing patent claims. In what I hope is a refreshing indication of things to come, the sober Court demonstrated it isn’t going to swallow every narrowing claim construction argument that comes along, even if brought to you by your friends at Budweiser.

The case was a declaratory judgment action wherein Anheuser-Busch sued first, hoping to establish non-infringement. The patent concerned beer cans (sorry, “beverage” cans) and in particular the end configuration where the pop-top is. The issue was claim construction. Even though the claim simply called for a “chuck wall dependent from an interior of the cover hook,” A-B argued that this requires a “flat-wall” frustoconical shape and argued that all sorts of limitations should be found in the claim, even though they don’t actually appear in the claim language.

What I like about this decision is that the Court rejected what I think are pretty ridiculous arguments on the part of A-B.

For example, A-B argued that only a “flat wall” can be form an angle with respect to the central axis of a can and that an arcuate wall would form an infinite number of angles. The Court rejected this sophistry with the observation that a flight of stairs is inclined relative to horizontal even though each individual step is horizontal in itself.

The Court similarly rejected A-B’s other arguments, finding that they are contrary to long-standing law or are simply contradicted by the plain language of the claims and prosecution history.

The Court held that the District Court erred in dismissing the case on summary judgment and sent the case back down with instructions to use the right claim construction this time around.

Again, it’s probably too early to tell whether this is simply one decision in one case, or whether it signals a return to balance on the part of the Federal Circuit. Too, it’s only an unreported decision that cannot be used as precedent. But even so, I’m happy the Court reached the decision it did. This is an encouraging development for patentees.