The tragedy unfolding in Fukushima is no laughing matter, but some could not hide a chuckle when it was announced that giant concrete pumps known under their brand name "Putzmeister" were sent to Japan to pour water on the damaged reactors, or, as some have re-phrased it, squirt liquid over the hot core.
In Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 234 F.3d 558 (Fed. Cir. 2000) (en banc), this court held that prosecution history estoppel acts as a complete bar to the doctrine of equivalents, so that a claim limitation that has been narrowed by amendment must be limited to its strict literal terms. Shortly before oral argument in this case, the Supreme Court vacated our decision in that case. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 122 S. Ct. 1831 (2002). The Supreme Court rejected the “complete bar” approach and required instead an examination of the subject matter surrendered by the narrowing amendment. Id. at 1840. In so doing, the Court adopted a rebuttable presumption that the narrowing amendment surrendered the particular equivalent in question, and discussed several ways in which the patentee could overcome that presumption. Id. at 1842. The patentee can overcome the presumption that prosecution history estoppel bars a finding of equivalence, the Court explained, if the patentee can show that the asserted equivalent was unforeseeable, that the rationale underlying the amendment bears only a tangential relation to the equivalent in question, or that there is some other reason that the patentee could not reasonably be expected to have described the substitute in question. Id. at 1841-42.At oral argument, Schwing contended that if we conclude that the amendment narrowed the annular extension limitations, we should remand the case to the district court to determine, in light of the Supreme Court’s Festo opinion, whether Schwing can successfully rebut that presumption. We agree with Schwing that, at least as to the modified Bastardring II device, the case should be remanded to the district court to determine, in the first instance, whether Schwing can rebut the Festo presumption. A remand is not necessary with respect to the Bastardring II device, however, because in light of the written description of the ’657 patent the embedded metal ring in the Bastardring II cannot be deemed equivalent to the annular extension on the shutter mechanism recited in claim 1.