## Facts

- Dunlop owned a patent claiming a golf ball cover made from certain synthetic ionomer resins (including Surlyn) that provided exceptional cut resistance.
- Ram manufactured and sold Surlyn-covered golf balls that would infringe if the patent were valid.
- In 1964, “Butch” Wagner experimented with Surlyn as a golf ball cover, producing sample balls and testing their durability.
- Wagner refined the composition to obtain acceptable weight, color, and mold-release characteristics and, by November 5, 1964, had a formula he deemed suitable for commercial production, corroborated by a contemporaneous handwritten memorandum.
- Wagner distributed Surlyn-covered golf balls to friends and potential customers during fall 1964 and moved toward commercial sales in early 1965.
- Dunlop’s earliest provable invention date was February 10, 1965.
- Dunlop sued Ram for infringement; Ram asserted invalidity based on Wagner’s prior invention and public use under 35 U.S.C. § 102(g).

## Issues

1. Whether the district court clearly erred in finding that Wagner conceived and reduced the invention to practice before Dunlop’s February 10, 1965 invention date.
2. Whether Wagner “suppressed or concealed” the invention under 35 U.S.C. § 102(g) by not disclosing the formula and not seeking patent protection, despite distributing the golf balls for public use.

## Decision

- The Seventh Circuit affirmed judgment for Ram and held Dunlop’s patent invalid.
- The court upheld the district court’s finding that Wagner was the prior inventor and that his work and public activity predated Dunlop’s invention date.
- The court held that Wagner’s public use and distribution of the golf balls foreclosed a finding of “suppression or concealment” under § 102(g), even though he did not disclose the underlying formula or pursue a patent.

## Legal Principles

- Under pre-AIA 35 U.S.C. § 102(g), a patent is barred if, before the applicant’s invention, the invention was made by another in the United States who had not abandoned, suppressed, or concealed it.
- Appellate review of district-court findings on prior invention is for clear error; documentary corroboration and credited testimony can sustain a finding of earlier conception and reduction to practice.
- Public use and distribution of an article embodying the invention generally defeats a claim of “suppression or concealment” under § 102(g).
- Failure to disclose manufacturing details (such as a formula) or failure to file for patent protection does not, by itself, constitute suppression or concealment when the invention is made available to the public through use or distribution.
- “Suppression or concealment” analysis may differ where the invention is kept secret (e.g., a secret machine or process whose benefits are not made available beyond the inventor), but that rationale does not apply when the product itself is in public use.

## Conclusion

The court invalidated Dunlop’s patent because Wagner had already invented and publicly used the Surlyn-covered golf ball before Dunlop’s provable invention date, and Wagner’s public distribution of the product prevented Dunlop from avoiding § 102(g) on a theory of suppression or concealment.


Dunlop Holdings Ltd. v. Ram Golf Corp., 524 F.2d 33 (7th Cir. 1975)