Summary: CAFC rules that foreseeability of an equivalent at the time of application does not bar infringement under the doctrine of equivalents.

Case: Ring & Pinion Service Inc. v. Arb Corp., No. 2013-1238 (Fed. Cir. Feb. 19, 2014) (precedential). On appeal from W.D. Wash. Before Moore, Clevenger, and Reyna.

Procedural Posture: Declaratory Judgment Defendant, patentee, appealed summary judgment of non-infringement. Judgment reversed and remanded.

  • Infringement (doctrine of equivalents): The sole issue before the district court was whether finding an equivalent to an element in a means-plus-function claim under the doctrine of equivalents is barred if the alleged equivalent was foreseeable at the time of the patent application. The parties had stipulated “that there were ‘no issues of material fact regarding infringement under the doctrine of equivalents’” because Declaratory Judgment Plaintiff’s product literally met all but one claim limitation and that an equivalent existed for such limitation. They further stipulated that the equivalent would have been foreseeable at the time of the application. The district court correctly determined that foreseeability of an equivalent at the time of application does not bar infringement under the doctrine of equivalents but incorrectly held that claim vitiation prevented a finding of infringement. The CAFC held that the district court erred when it failed to follow the parties’ stipulation and added that vitiation is not an exception to the doctrine of equivalents because it is a legal determination that no reasonable jury could determine two elements to be equivalent, which the stipulation precluded.