Doctrine of Equivalents Must Be Applied on Element-By-Element Basis

A Federal Circuit panel, in Miken Composites v. Wilson Sporting Goods Co. (No. 2006-1628; February 6, 2008), affirms a district court’s summary judgment determination that certain softball and baseball bats did not infringe a patent related to an improved bat design. The panel reviews and affirms the district court's claim construction as well as the determination of non-infringement.

In the patented bat design, a tubular insert is suspended within the impact portion of the tubular frame of the bat, yielding leaf-spring characteristics. One of the disputed claim terms was "insert", which had previously been construed to have its plain meaning of "something inserted or intended for insertion." The patentee (Wilson) argued that the district court erred in its construction because, it contended, the district court was importing a process limitation into claims for a product. The panel disagreed, finding that even though the meaning of the claim term has functional attributes, it nonetheless recites a structural component.

The panel affirms a finding of no literal infringement with respect to both Miken's carbon and non-carbon bats. Next, the panel reviews the district court's finding that the carbon bats do not infringe under the doctrine of equivalents. The panel concludes that Wilson had shown, at most, “the equivalency of the accused products as a whole.” In order to infringe under the doctrine of equivalents, however, the panel states that an objective inquiry must be made on an element-by-element basis. Therefore, non-infringement under the doctrine of equivalents is affirmed.