J.L. Clark, Inc.

Weatherchem Corporation sued J.L. Clark, Inc. for infringement of U.S. Patent 4,936,494 and U.S. Patent 4,693,399. The district court held the '494 patent invalid for obviousness and alternatively not infringed, and held the '399 patent invalid under the on-sale bar but infringed. On appeal, the Federal Circuit affirmed in part, modified in part, and vacated the '399 on-sale-bar determination for reconsideration under Pfaff v. Wells Electronics.