Muncie Gear Works, Inc. v. Outboard, Marine & Manufacturing Co.

Harry Johnson sought to patent a water-propulsion device. The original application, filed in 1926, was rejected, as were amendments to the application made in 1927. In December 1928, Johnson added new claims to the application. By this point, the invention no longer resembled the device originally claimed. The latest version included plates to guard against cavitation—i.e., a propeller’s drawing of air from the surface of the water, which reduces propulsive power—and smooth-walled housings. The patent was granted in 1929 and assigned to Johnson Brothers Engineering Corporation (Johnson) (plaintiff) and licensed to Outboard, Marine & Manufacturing Company (Outboard) (plaintiff). Johnson and Outboard brought an infringement action against Muncie Gear Works, Inc. (Muncie) (defendant), which manufactured outboard motors similar to Johnson’s claimed invention, and Bruns & Collins, Inc. (Bruns) (defendant), which sold Muncie’s motors. Muncie and Bruns cited prior commercial use of the motors by Johnson in early 1926—more than two years before the version of the patent application that was ultimately accepted—and argued that this triggered a bar against patent validity. The evidence of public use and sale was not contradicted. The federal district court and the court of appeals did not directly address the issue of prior public use, but the latter court held that the patent’s claims were valid and infringed. Muncie and Bruns appealed. The United States Supreme Court granted certiorari.