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Claim Term “Substantially Constant” Is Not So Indefinite as to Invalidate

November 14, 2002

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Last Month at the Federal Circuit - January 2003

Judges: Newman (author), Lourie, and Clevenger

In Verve, LLC v. Crane Cams, Inc., No. 01- 1417 (Fed. Cir. Nov. 14, 2002), the Federal Circuit vacated a district court’s SJ of indefiniteness under 35 U.S.C. § 112, ¶ 2, reversed a judgment of invalidity for anticipation under 35 U.S.C. § 102, and remanded.

The patent-in-suit, U.S. Patent No. 4,850,315 (“the ’315 patent”), relates to stronger push rods for internal-combustion engines used, for example, in automobiles. Push rods are part of the mechanism that open and close air intake and exhaust valves within the cylinders of engines. Specifically, the ’315 patent claims a hollow push rod made from a single piece of metal with a diameter that is larger at the middle portion than at either end.

The claims recite a hollow push rod having a “substantially constant wall thickness” throughout the length of the tube. Because the intrinsic evidence did not define “substantially constant,” the district court held the claims invalid as indefinite. The Federal Circuit concluded that the district court employed the wrong standard, ruling that the district court should have focused on whether a person of ordinary skill in the art would understand the term rather than on whether the intrinsic evidence alone provided a clear definition. The Court observed that “substantially” often serves a valid purpose in patent claims. In fact, the very nature of the invention may necessitate its usage, so that the patentee can claim the true scope of the invention. Accordingly, the Court vacated the indefiniteness decision and remanded.

The Federal Circuit also reversed the district court’s judgment of anticipation by two Japanese patents. Notably, the asserted references merely disclosed hollow push rods having a uniform, cylindrical diameter with slightly narrower spherical-shaped ends. The Court essentially determined that the claims, when properly construed, did not cover such a configuration. Accordingly, the ’315 patent was not invalid for anticipation.