## Facts

- The dispute involved U.S. Patent No. 4,009,735, directed to removable, rewettable thermal insulation for vessels and piping in nuclear power plants.
- The patent issued from a Rule 60 continuation filed Oct. 2, 1974, claiming priority to a parent application filed Oct. 24, 1973; the continuation added no new matter.
- Transco sought a declaratory judgment of invalidity, noninfringement, and unenforceability after Performance accused Transco of infringement.
- On summary judgment, the district court held claims 1–4 invalid for three alleged best mode violations under 35 U.S.C. § 112:
  - Two based on a supposed obligation to update best mode upon filing the continuation.
  - One based on failure to disclose supplier/trade-name information for a material described in the patent.
- Performance appealed, challenging the continuation-best-mode legal rule and the summary-judgment resolution of the supplier/trade-name issue.

## Issues

1. Whether 35 U.S.C. § 112 requires an inventor to update the best mode disclosure when filing a continuation application that adds no new matter and claims priority under 35 U.S.C. § 120.
2. Whether summary judgment was improper because factual disputes existed as to whether omission of supplier/trade-name information constituted concealment of the inventor’s best mode.

## Decision

- The Federal Circuit reversed the summary judgment invalidity determination insofar as it rested on an asserted duty to update best mode when filing a no-new-matter continuation.
- The court held the district court erred as a matter of law in treating the continuation filing as triggering a new best mode obligation for common subject matter.
- The court vacated the district court’s third best-mode finding (supplier/trade-name omission) because the district court resolved genuine issues of material fact on summary judgment.
- The case was remanded for further proceedings on the supplier/trade-name issue.

## Legal Principles

- For a continuation application that adds no new matter and properly claims priority under § 120, best mode for the common subject matter is evaluated as of the parent application’s filing date, not the continuation filing date.
- There is no per se statutory duty to update best mode solely because a continuation is filed without new matter.
- Best mode disputes commonly turn on fact questions, including the inventor’s subjective preference and whether the disclosure enables a skilled artisan to practice the preferred mode without concealed information.
- Summary judgment is improper where evidence permits competing findings on whether an omission (including supplier/trade-name information) amounts to concealment or renders the disclosure inadequate.

## Conclusion

The Federal Circuit rejected a continuation-based “best mode updating” requirement for no-new-matter continuations, reversed the corresponding invalidity rulings, and vacated the supplier/trade-name best-mode determination because it depended on disputed facts requiring further proceedings.


Transco Prods., Inc. v. Performance Contracting, Inc., 38 F.3d 551 (Fed. Cir. 1994)