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Tangential Equivalents: Recent Case Confirms There Is Life After Festo

On Oct. 4, 2004, the Federal Circuit rendered its opinion in <i>Insituform Techs., Inc. v. Cat Contracting, Inc.</i> ("<i>Insituform IV</i>"), 385 F.3d 1360 (Fed. Cir. 2004). This opinion is the first post-<i>Festo</i> Federal Circuit opinion that finds a successful rebuttal of the <i>Festo</i> presumption (<i>eg</i>, the presumption of the surrender of infringement under the doctrine of equivalents due to prosecution history estoppel) based on the "tangential relationship" prong of <i>Festo</i>. This case seems to set a fairly low bar for the rebuttal of the presumption. This is a significant development given the Federal Circuit's apparent desire to restrict the doctrine of equivalents (as reflected in its initial <i>Festo</i> ruling that was reversed by the Supreme Court, as well as by the tenor of the post-reversal <i>Festo</i> opinion).

25 minute readNovember 30, 2004 at 01:54 PM
By
Hope Melville
Donald E. Daybell
Tangential Equivalents: Recent Case Confirms There Is Life After Festo

On Oct. 4, 2004, the Federal Circuit rendered its opinion in Insituform Techs., Inc. v. Cat Contracting, Inc. (“Insituform IV

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