'All-Limitations Rule' Applies Strictly To Doctrine of Equivalents Infringement

The U.S. Court of

Appeals for the Federal Circuit recently reiterated the rule of Warner-Jenkinson,

that the doctrine of equivalents will not be applied so broadly as to wholly

eliminate a limitation recited in a claim. Cooper Cameron Corp. v. Kvaerner

Oilfield Products Corp., Nos. D1-1383, -1408 (Fed. Cir. May 14, 2002).

Cooper owns patents

related to subsea wellheads that protect the well during maintenance and

repair. The claim at issue recites, "[a] wellhead comprising Ö a workover

port extending laterally through the wall of the spool tree from between the

two plugs" (emphasis added). The accused device had a workover port

placed above the two plugs. Cooper claimed infringement of its patent

under the doctrine of equivalents.

The Federal Circuit

affirmed the district court's grant of summary judgment, holding that the

defendant's workover port enters the wellhead assembly "above" the

two plugs, which "cannot be equivalent to a connection 'between the two

plugs.'" The Court rejected Cooper's argument that the location of the

workover port was irrelevant to its operation and thus was not an essential

element to the claim, reasoning that to ignore Cooper's decision to include

"between" as a limitation in...