Goodman

This is an action for infringement of the broad claims 6 and 8 of patent No. 1,-917,261 for a method of retreading worn tire casings, issued to P. E. Hawkinson July 11, 1933 upon application filed May 14, 1931. The trial court held that claim 6 was invalid but that claim 8 was valid and infringed by the defendant. Both sides appeal.

This patent was considered by the Circuit Court of Appeals for the Eighth Circuit in Gamble Skogmo v. Hawkinson Co., 98 F.2d 37 , wherein it was held that claim 6, if valid, should be narrowly construed and, so construed, was not infringed.

At the time Hawkinson applied for his patent the method of retreading or repairing worn automobile tire casings was to cover the worn surface of the tire with a composition of rubber and sulphur suitable for vulcanization and then to vulcanize the composition by the application of pressure and heat in a suitable machine. The method of vulcanizing rubber was well known and the obvious point for the application of the new rubber composition was in the place where the rubber had been worn away.

Many patents had been issued prior to the application of Hawkinson on June 11, 1933 for appliances for vulcanizing the…