In another narrow application of the doctrine of claim element vitiation, the U.S. Court of Appeals for the Federal Circuit held that an accused product having a "rotatably mounted" movable end did not infringe patent claims reciting a "slidably mounted" element under the doctrine of equivalents. Freedman Seating Co. v. American Seating Co., Case Nos. 04-1216, -1248 (Fed. Cir. Aug. 11, 2005) (Schall, J.).
In a patent infringement case involving a cantilevered stowable seat for public transportation vehicles (the seat can be folded away to create more interior space for accommodating passengers with wheelchairs), the district court granted summary judgment finding the accused infringer, American Seating, infringed Freedman’s patent under the doctrine of equivalents. In its infringement analysis, the district court found the rotatably mounted movable end of the accused seats was equivalent to the "slidably mounted" movable end of the claimed seats and thus infringed under the doctrine of equivalents.
The Federal Circuit reversed, finding the district court’s decision violated the Warner-Jenkinson "all limitations" rule, which requires that "an element of an accused product or process is not . . . equivalent to a limitation of the claimed invention if such a finding would entirely vitiate the limitation." Acknowledging there is no "set formula" for determining when a finding of equivalence would vitiate a claim limitation, the Court instructed that, to make the determination, "courts must consider the totality of the circumstances of each case and determine whether the alleged equivalent can be fairly characterized as an insubstantial change from the claimed subject matter without rendering the pertinent limitation meaningless."
The Court took the opportunity to present a useful survey of its prior "all elements rule" cases. After noting the movable end of the accused product can only rotate but cannot slide or move along the base of the seat, the Federal Circuit concluded that this structural difference was not an "insubstantial change" and held that allowing the slidably mounted limitation to cover the accused product would read the limitation completely out of the claims and vitiate the limitation. Thus, the Court found the accused product’s rotatably mounted movable end was not equivalent to the slidably mounted limitation, and there was no infringement under the doctrine of equivalents.
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