Fry, A. L. (1993). U.S. Patent No. 5,194,299. Washington, DC: U.S. Patent and Trademark Office.
(Fry, 1993)
Most patent APA citations have four basic elements:
Fry, A. L.
(1993).
U.S. Patent No. 5,194,299.
Washington, DC: U.S. Patent and Trademark Office.
See The University of Akron's Bluebook Quick Reference: Abbreviations and How-tos for help with abbreviations​.
See Publication Manual, 11.8