This is the latest installment in a string of cases from the Federal Circuit attempting to curb what it sees as an abuse of the vitiation doctrine when considering equivalency. For vitiation to apply and bar equivalency, the element at issue must really be the antithesis of the claimed structure.
Background / Facts: The patent here is directed to a two-pipe drill for boring underground holes in the horizontal direction. An inner pipe rotates the drill bit while an outer pipe, which includes a body and casing, is used for steering. On this structure, the patent provides a “deflection shoe” that is “mounted on” the body or casing as a steering mechanism. The deflection shoe is included on one side to create an asymmetry about the casing’s centerline axis, causing the drill to deflect away from a straight path if the casing does not rotate. The accused device does not literally infringe as it does not use a deflection shoe, but alternatively employs a “bent sub” arrangement where an elbow is provided in the pipe body to similarly steer the drill bit by reacting with the side of the bore hole.
Issue(s): Whether a finding of equivalence for the “bent sub” arrangement in the accused device would read the “deflection shoe” and “mounted on” limitations out of the claims, and thus be barred by the doctrine of claim vitiation.
Holding(s): No. The court began by emphasizing that the proper inquiry under the doctrine of equivalents is simply the classic function-way-result test, i.e., “whether the substitute element matches the function, way, and result of the claimed element.” Quoting recent decisions on the topic, the court reiterated its current position that vitiation is no more than “a legal determination that ‘the evidence is such that no reasonable jury could determine two elements to be equivalent.’” That is, “saying that a claim element would be vitiated is akin to saying that there is no equivalent to the claim element in the accused device based on the well-established ‘function-way-result’ or ‘insubstantial differences’ tests.” Under this framework, the court quickly dismissed the vitiation assertions. “We … conclude that the doctrine of claim vitiation does not bar CMW’s application of the doctrine of equivalents.”