General Electric Co. v. Wabash Appliance Corp.

Background

General Electric, a company making lamp filaments, sued for infringement based on Pacz Patent No. 1,410,499, issued March 21, 1922, from an application filed February 20, 1917. The patent described a tungsten filament said to reduce “offsetting” and “sagging” by having comparatively large grains. The District Court found the claimed filaments valid and infringed, but the Second Circuit reversed as anticipated by an earlier Coolidge patent; a Ninth Circuit conflict led the Court to review the case.

Reasoning

The Court addressed whether the product claims (typified by claim 25) met the patent statute’s requirement to describe clearly what is new. The Court assumed the specification taught how to make and use the filament, but held the claims themselves were legally defective. Claim language described the filament by its effect (preventing sagging and offsetting) and said only that it had “comparatively large grains” without defining their shape, size, or contour. The opinion explains that a patentee cannot claim a product solely by what it does or by vague functional terms, and that the specification and process description here did not supply definite structural limits to save the product claims. The Court therefore found claims 25, 26, and 27 invalid.

Real world impact

Because the product claims were invalid, the patent owner cannot enforce those claims or maintain the injunction and accounting awarded by the District Court. The decision emphasizes that patent claims must clearly define the structural limits of a claimed product so others know what is off-limits during the patent’s life. The ruling resolves the conflict in the circuits by affirming the judgment that these specific product claims are invalid.