Engel Industries, Inc. v. Lockformer Co.

946 F.2d 1528, 20 U.S.P.Q.2d 1300 (1991)

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Engel Industries, Inc. v. Lockformer Co.

United States Court of Appeals for the Federal Circuit
946 F.2d 1528, 20 U.S.P.Q.2d 1300 (1991)

Facts

Robert Heilman and Howard McElroy invented a means of connecting air ducts before or after installation with corner connectors, without the need for rivets or spot welds. A patent (the ‘641 patent) on the invention was issued to Met-Coil Systems Corporation (Met-Coil) (defendant), the parent company of Heilman’s and McElroy’s respective employers, the Lockformer Company (defendant) and Iowa Precision Industries (Iowa Precision) (defendant). Engel Industries (Engel) (plaintiff), a licensee under the ‘641 patent, sought a declaratory judgment of patent invalidity and noninfringement. The federal district court found the patent invalid under § 112 of the patent statute, which required a patent to specify the best mode of practicing the claimed invention. The decision was based on evidence that crimping the corner connectors after snapping them into place was a better mode of practicing the invention than simply snapping the corners into place without additional steps. The ‘641 patent did not mention crimping. However, several months later, Lockformer added a crimping step to the instructions included with the product in response to complaints from customers. Lockformer, Iowa Precision, and Met-Coil appealed to the United States Court of Appeals for the Federal Circuit.

Rule of Law

Issue

Holding and Reasoning (Newman, J.)

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