## Facts

- Caterpillar Tractor Company filed an international patent application under the Patent Cooperation Treaty (PCT) with the U.S. Patent and Trademark Office (PTO) acting as the Receiving Office.
- The application included method (process) claims (claims 1–4) and apparatus claims (claims 5–9) intended to carry out the claimed process.
- Under PCT Rule 13.2(ii), Caterpillar sought to prosecute the process and one apparatus “specifically designed” to perform the process in a single international application.
- The PTO, applying 37 C.F.R. § 1.141(b)(2) and related guidance, determined the application lacked “unity of invention” because the apparatus could be used in another materially different process and/or the process could be practiced with another materially different apparatus.
- The PTO’s unity determination effectively required Caterpillar to proceed as if two separate inventions were claimed, requiring restriction.
- After the Assistant Commissioner for Patents reaffirmed the determination on reconsideration, Caterpillar filed a civil action challenging the PTO rule and its application as inconsistent with the PCT.
- The case was presented on cross-motions for summary judgment.

## Issues

1. Whether the PTO may condition unity of invention for a PCT application on a requirement that the apparatus “cannot be used to practice another materially different process.”
2. Whether the PTO’s unity-of-invention rule and interpretive practice impose form or content requirements “different from or additional to” those provided by the PCT and its Regulations, contrary to PCT Article 27(1).
3. Whether the PTO’s determination that Caterpillar’s method and apparatus claims lacked unity of invention was contrary to law.

## Decision

- The court granted summary judgment for Caterpillar.
- The court held the PTO’s unity-of-invention rule and its application to Caterpillar’s PCT application conflicted with PCT Rule 13 and violated PCT Article 27(1).
- The court set aside as unlawful the PTO determinations concluding Caterpillar’s method and apparatus claims lacked unity of invention.

## Legal Principles

- For PCT international applications, national implementing rules may not impose requirements relating to the form or contents of the application that are different from or additional to those in the PCT and its Regulations (PCT art. 27(1)).
- PCT Rule 13.2(ii) permits, in a single international application, an independent process claim and an independent claim to an apparatus or means “specifically designed” to carry out that process.
- The PTO may not reinterpret “specifically designed” to add a substantive limitation that unity exists only if the apparatus cannot be used for another materially different process (or if the process cannot be practiced by a materially different apparatus), where that limitation is not required by the PCT standard.
- Agency implementation of treaty-based standards must conform to the treaty’s text and regulatory scheme; an agency may not use domestic restriction practice to narrow treaty-permitted claim groupings in PCT applications.

## Conclusion

The court held that the PTO unlawfully imposed an extra “materially different process” restriction on PCT unity of invention, and it invalidated the PTO’s unity determination that forced Caterpillar’s process and apparatus claims into separate inventions for filing purposes.


Caterpillar Tractor Co. v. Comm’r of Patents & Trademarks, 231 U.S.P.Q. 590 (E.D. Va. 1986)