Douglass v. United States Appliance Corp.

HEALY, Circuit Judge.

This appeal presents the question whether the estoppel running against an assignor of a patent to assert its invalidity extends to third persons who acquire by purchase other and later patents of the assignor found to infringe the assigned patent. We think in the present state of the law the question must be answered in the negative.

Ralph M. Keele made application for patent for a hair waving device and simultaneously for a valuable consideration assigned the application to appellee. On December 18, 1934, letters patent No. 1,984,585 issued to appellee on the application.…