Emmett

The judgment appealed from enjoined infringement of a patent by appellant, and was entered in an action brought by appellees, who sought to restrain appellant from infringing letters patent No. 1,947,-493 issued on February 20, 1934, on an application filed July 17, 1931 by one Rose and one Engle as joint inventors. The applicants assigned their rights to appellee Rose-Engle Company, a California corporation, by assignment recorded in the patent office on April 17, 1933. Appellee Metals Processing Corporation, a Nevada corporation, is the exclusive licensee of RoseEngle Company under the patent.

The patent covers a process of coating machine elements with spring-steel or the like, in order to impart a hard smooth surface to such elements. The specification described the process for covering a piston. The piston is centered in a lathe, and a lathe tool is used at a setting which will cut v-shaped grooves in the surface of the piston and which will break the metal slightly and leave the pores of the metal open and rpugh to give an adhering surface upon which to spray the metal. The edges of the first and last grooves are undercut. After the grooves have been cut, the piston is…