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Prosecution History Restricts Claim Scope

March 11, 2005

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Last Month at the Federal Circuit - April 2005

Judges: Prost (author), Lourie, and Schall

In Sentry Protection Products, Inc. v. Eagle Manufacturing Co., No. 04-1392 (Fed. Cir. Mar. 11, 2005), the Federal Circuit affirmed the district court’s construction of the claim terms at issue and its SJ ruling of invalidity with respect to claims 10 and 23 of U.S. Patent No. 6,244,781 (“the ‘781 patent”). The Federal Circuit also vacated the district court’s grant of SJ of noninfringement of U.S. Patent No. 6,102,611 (“the ‘611 patent”) and remanded for further proceedings on that patent.

The ‘781 and the ‘611 patents disclose barriers used for protecting structural columns and supports from impact damage by a moving vehicle while reducing or preventing damage to the vehicle and its driver. Such barriers may be useful in warehouses or other structures that experience vehicle traffic on a regular basis. The claimed apparatus includes a plurality of impact-protection components configured to fit beside each other in installed positions in which the components define segments of an impact-protection body. Each of the components is a single unitary part having a peripheral side wall with a rear portion configured to mate with the structural support being protected.

The first issue on appeal was whether the meaning of the term “single unitary part,” as used in the claims of the ‘781 patent, includes impactprotection components having multiple parts. The allegedly infringing Eagle Manufacturing Company (“Eagle”) device includes multiple components that are secured together and are not separable. The district court construed this term as a component comprised of only one piece.

The Federal Circuit reviewed the prosecution history of the ‘781 patent and noted that the prior art cited during the prosecution of the ‘781 patent disclosed an impact-protection component made of multiple parts. The Court found that by amending its claims to include the limitation “single unitary part” and arguing that this amendment distinguished its application from the multicomponent impact-protection assembly of the prior art, Sentry gave up coverage of multipart impact-protection components. Accordingly, the Court affirmed the district court’s interpretation of the term as meaning that the impact-protection component is a single part without any additional pieces.

The Court then moved on to determine whether claims 10 and 23 of the ‘781 patent were invalid in view of U.S. Patent No. 5,497,723 (“Chase”). Chase discloses a boat bumper that protects posts on a dock from impact by boats. The district court interpreted Chase as teaching a cushion having a single unitary part and found that the other components discussed in Chase (a post, a crosspiece, and mounting brackets) are not part of the impact-protection component. The Federal Circuit agreed and affirmed the district court’s judgment that these claims were invalid.

The Federal Circuit found that the district court had misapplied the constructive-notice rule with respect to the ‘611 patent. The Court opined that constructive notice is provided when the patentee consistently marks substantially all of its patented products. The Federal Circuit held that because Sentry produced an affidavit stating that its products were marked, together with documents showing sales in that period, the district court erred by holding that Sentry’s marking evidence did not preclude SJ.