## Facts

- Metallizing Engineering Co., Inc. sued Kenyon Bearing & Auto Parts Co., Inc. for infringement of a reissue process patent covering a method for preparing a metal surface to improve bonding of subsequently sprayed molten metal in rebuilding worn machine parts.
- The claimed method used an electric-arc device to deposit a preliminary metal layer onto the base, creating a rough, cratered surface, followed by conventional spray-metal application.
- Metallizing used the process in its business of reconditioning customers’ parts for profit, returning rebuilt parts to customers as a service rather than selling the apparatus or openly disclosing the method.
- Metallizing intentionally kept the process secret; customers could not determine the method from the rebuilt parts.
- The patent application was filed on August 6, 1942; evidence showed Metallizing had commercially used the process more than one year before that filing date.
- The district court held the reissue patent valid and infringed and rejected defenses including prior use, abandonment, and lack of invention.
- Defendants appealed.

## Issues

1. Whether an inventor’s secret, profit-driven commercial use of a process more than one year before filing triggers the statutory bar associated with “public use”/commercial exploitation, rendering the patent invalid even though the use did not disclose the process to the public.
2. Whether the inventor’s activities qualified as experimental use sufficient to avoid the statutory bar.

## Decision

- The Second Circuit reversed the judgment of validity and infringement and directed dismissal of the complaint.
- The court held the patent invalid because the inventor (through Metallizing) commercially exploited the process more than one year before filing.
- The court found the use was not experimental; it was primarily for profit and competitive advantage while withholding disclosure.

## Legal Principles

- An inventor who commercially exploits an invention after it is ready for patenting for more than the statutory period before filing forfeits the right to a patent, even if the exploitation is secret and the public cannot learn the invention from the product.
- “Public use” for purposes of the statutory bar can include the inventor’s non-informing commercial practice of a process as part of a business, where the inventor gains competitive benefit while delaying patent disclosure.
- The policy of the statutory bar prevents extending effective exclusivity by combining trade-secret exploitation with a later patent term.
- Secret commercial use by the inventor is treated differently from secret use by third parties; the forfeiture doctrine targets the inventor’s own choice to profit while postponing filing.

## Conclusion

The court invalidated the process patent because the inventor’s assignee had used the process commercially and secretly for more than one year before filing, a forfeiture that bars later patenting even though the public could not ascertain the process from the serviced parts.


Metallizing Eng'g Co. v. Kenyon Bearing & Auto Parts Co., 153 F.2d 516 (2d Cir. 1946)