In a case on remand from the U.S. Supreme Court, a three-judge panel of the U.S. Court of Appeals for the Federal Court struck its earlier decisions Insituform I, II and III, ruling the patent owner (Insituform) had successfully rebutted the Festo presumption barring use of the doctrine of equivalents. The panel held that while a narrowing amendment had been made, it bore “‘only a tangential relation,’ if that, ‘to the equivalent in question.’” Insituform Technologies, Inc. v. CAT Contracting, Inc. et al., Case Nos. 99-1584, 00-1005 (Fed. Cir. 10/4/04) (Shall, J.).
This case has now been to the Federal Circuit four times.
In Insituform I and II (1996 and 1968 respectively), the Federal Circuit ruled Insituform was not barred by prosecution history estoppel from asserting infringement under the doctrine of equivalents between the recited single cup for drawing a vacuum along a pipe liner and the accused process that used several cups or needles for the same purpose.
In Insituform III, (2001) the Federal Circuit, relying on its initial en banc Festo holding, Festo I, (2002) i.e., a narrowing amendment made for a reason related to patentability completely bars application of the doctrine of equivalents as to that limitation, reversed itself and held that based on a narrowing amendment that recited a single vacuum cup, Insituform was not entitled to assert any range of equivalents as to that limitation. After the Supreme Court overruled the complete bar rule of Festo I, holding the so-called “Festo presumption” against application of the doctrine of equivalents was subject to rebuttal, it vacated the decision in Insituform III and remanded the case to the Federal Circuit. Now, in Insituform IV, the Federal Circuit has held that Insituform has successfully rebutted the Festo presumption; i.e., that a narrowing amendment made for a reason of patentability surrenders the entire territory between the original claim limitation and the amended claim limitation.
The technology in issue relates to a method for rehabilitating a damaged underground pipe without digging it up. The claim in issue resulted from the applicant combining original independent claim 1 (which did not specify the number of suction cups or locations of the vacuum source) with dependent claims 2, 3 and 4, to define over a prior art reference applied to all four claims by the U.S. Patent and Trademark Office (USPTO). Claim 4 recited the application of vacuum to the pipe liner from a single, movable cup. The prior art reference in question used a continuous vacuum created by a single vacuum source. The accused process used by CAT Contracting employed multiple suction cups placed along a tube. In Insituform IV, the Federal Circuit held that the amendment, narrowing the scope of literal coverage from multiple suction cups to a single suction cup, bore “no more than a tangential relation to the equivalent in question” and was, therefore, not barred by the Festo presumption.
This decision addresses one of the three Festo bar presumption “rebuttal” possibilities discussed by the en banc Federal Circuit in Festo III (2003): (i) the patentee may demonstrate that “the alleged equivalent would have been unforeseeable at the time of the narrowing amendment;” (ii) the patentee may demonstrate that “the rationale underlying the narrowing amendment bore no more than a tangential relation to the equivalent in question;” or (iii) the patentee may demonstrate “‘some other reason’ suggesting that the patentee could not reasonably have been expected to have described the alleged equivalent.”
The Federal Circuit, citing Festo III, noted that “[w]hether the patentee has established a merely tangential reason for a narrowing amendment is for the court to determine from the prosecution history record without the introduction of additional evidence, except, when necessary, testimony from those skilled in the art as to the interpretation of that record.” After considering the matter, the Federal Circuit found that the basis articulated in the prosecution history for distinguishing the claim over the prior art applied was not the number of suction cups but the placing of the vacuum source closer to the cup, thereby permitting use of a smaller compressor. Thus, the Federal Circuit held that Insituform has successfully met the “tangential relationship” rebuttal test articulated in Festo III.
In terms of analyzing when use of the doctrine of equivalents is barred and when it is available (and if available to what extent) Insituform IV takes us back closer to the pre-Festo days than many might have thought the Federal Circuit was likely to go. In light of this decision, and to preserve possible application of the “tangential relationship” rebuttal test of Festo III, patent prosecutors are well advised to precisely articulate to the USPTO the narrowest possible reason why a particular amendment distinguishes over the prior art. Although equivalents (under doctrine of equivalents ) will be lost for any structure or method to which the reason applies, it may at least be preserved for other structures (to which the stated reason does not apply). Opinion writers beware, the doctrine of equivalents is back!