## Facts

- An engineer, Harry L. Johnson, sought a patent relating to outboard-motor features intended to reduce propeller cavitation.
- Johnson filed a patent application in August 1926, but it did not disclose the combination later asserted in the infringement suit.
- Johnson commercially used and sold outboard motors embodying the later-claimed combination in early 1926.
- In December 1928, Johnson amended the application to add claims (including claims 11–14) incorporating key anti-cavitation features.
- The patent issued in 1929 and was owned by Johnson Brothers Engineering Corp. and exclusively licensed to Outboard, Marine & Manufacturing Co.
- Johnson Brothers and the exclusive licensee sued Muncie Gear Works, Inc. (manufacturer) and Bruns & Collins, Inc. (seller) for infringement.
- Evidence of the early public use and sale was uncontradicted in the record.

## Issues

1. Whether claims 11–14 were invalid under R.S. § 4886 because devices embodying the claimed invention were in public use or on sale more than two years before the invention was first disclosed to the Patent Office.
2. Whether the Supreme Court could decide the statutory-bar issue even though it was not squarely addressed in the decisions below.
3. Whether late-added claims may capture subject matter not disclosed in the original filing when that subject matter had already been commercially exploited beyond the statutory period.

## Decision

- The Supreme Court reversed the judgment sustaining validity and infringement.
- Claims 11–14 were held invalid under R.S. § 4886 due to public use or sale more than two years before the first disclosure of the claimed invention to the Patent Office.
- The Court held it was not barred from reaching the statutory-bar issue despite its incomplete treatment in the lower courts.

## Legal Principles

- A patent claim is barred if the invention, as claimed, was in public use or on sale in the United States more than the statutory period before the invention was first disclosed in the application to the Patent Office.
- When a later amendment first introduces the disclosure that supports the asserted claims, the relevant timing for the public-use/on-sale bar is measured from that first supporting disclosure, not from an earlier filing that did not describe the invention later claimed.
- Amendments may refine or limit claims within the original disclosure, but they cannot validly be used to obtain claims to a new combination not originally disclosed when the subject matter has already entered public use or commercial sale beyond the statutory period.

## Conclusion

The Court invalidated the asserted claims because the invention they covered was first disclosed to the Patent Office only after it had already been publicly used and sold beyond the statutory window, and it addressed the statutory-bar question notwithstanding the lower courts’ limited treatment of that issue.


Muncie Gear Works, Inc. v. Outboard, Marine & Mfg. Co., 315 U.S. 759 (1942)