Chemcast Corporation v. Arco Industries Corporation
913 F.2d 923, 16 U.S.P.Q.2d 1033 (1990)
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Rule of Law:
An inventor's failure to disclose the specific supplier and trade name of the only material they contemplated for practicing their invention violates the best mode requirement of 35 U.S.C. § 112, as this information is necessary for one skilled in the art to practice the inventor's preferred embodiment.
Facts:
- Phillip L. Rubright, an employee of Chemcast Corporation, invented a dual durometer grommet designed to seal openings in sheet metal panels.
- The grommet consisted of a soft base portion and a harder, more rigid locking portion.
- For the locking portion, Rubright selected a specific rigid polyvinyl chloride (PVC) plastisol composition developed for Chemcast by Reynosol Corporation.
- Reynosol spent 750 man-hours developing this compound, which Chemcast purchased under the trade name R-4467.
- Rubright knew the preferred hardness of this material was 75 +/- 5 on the Shore D scale.
- At the time he filed his patent application, the grommet made with Reynosol's R-4467 compound was the only embodiment of the invention Rubright had ever contemplated or used.
- Rubright's patent application generically described the locking portion material as a 'rigid castable material... having a durometer hardness reading of 70 Shore A or harder,' without mentioning the specific PVC composition, its 75 Shore D hardness, Reynosol, or the R-4467 trade name.
- Arco Industries Corporation, a competitor, began manufacturing and selling a similar grommet.
Procedural Posture:
- Chemcast Corporation sued Arco Industries Corporation in the U.S. District Court for the Eastern District of Michigan for infringement of its '879 patent.
- Arco filed a counterclaim arguing the patent was invalid for, among other reasons, failure to disclose the best mode under 35 U.S.C. § 112.
- The district court (the court of first instance) held the patent was invalid on best mode grounds.
- Chemcast appealed to the U.S. Court of Appeals for the Federal Circuit (the intermediate appellate court for patent cases).
- The Federal Circuit vacated the district court's judgment, holding that the court had applied an incorrect legal standard for the best mode analysis, and remanded the case.
- On remand, the district court again held the patent invalid for failure to comply with the best mode requirement.
- Chemcast appealed the district court's decision on remand to the U.S. Court of Appeals for the Federal Circuit.
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Issue:
Does a patent's specification violate the best mode requirement of 35 U.S.C. § 112 when it fails to disclose the precise hardness, specific type, supplier, and trade name of a material that the inventor knew was the best, and only, mode of practicing the claimed invention?
Opinions:
Majority - Mayer, Circuit Judge
Yes. A patent's specification violates the best mode requirement when it fails to disclose information necessary for one skilled in the art to practice the inventor's preferred embodiment. The court established a two-part test for best mode analysis. The first part is subjective: did the inventor, at the time of filing, know of a mode of practicing the invention that he considered better than any other? Here, Rubright knew the R-4467 compound with a 75 Shore D hardness was not only the best mode but the only mode he had contemplated. The second part is objective: was the disclosure adequate to enable one skilled in the art to practice that best mode? Here, the disclosure was inadequate. The specification's reference to '70 Shore A or harder' was misleading and concealed the preferred 75 Shore D material, which is measured on a different hardness scale. Because Rubright did not know the formula for R-4467, he was obligated to disclose the supplier (Reynosol) and trade name to allow others to practice his best mode. An inventor cannot conceal the preferred embodiment under the guise of broad claim language or a supplier's trade secret.
Analysis:
This decision solidifies the two-component framework for the best mode inquiry, separating the subjective knowledge of the inventor from the objective adequacy of the disclosure. It establishes a significant precedent that an inventor's disclosure obligation extends beyond the literal scope of the claims to include non-claimed elements or specific commercial details, such as a supplier's trade name, if that information is necessary to practice the best mode. The ruling serves as a warning to patent applicants that they cannot conceal their preferred commercial embodiment, even if it relies on a third party's trade secret, thereby preventing inventors from obtaining patent protection while keeping the best version of their invention hidden from the public.
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