Lockwood

This is an action for patent infringement in which the defendants counter *84 claimed for declaratory relief. Both sides appeal and consequently we will refer to them as plaintiffs and defendants, rather than as appellants and appellees. Plaintiff Lockwood is a patentee of, and plaintiff Mid-West Metallic Products, Inc. is the licensee under, patent No. 2,-931,535 (hereafter referred to as ’535) issued April 5,1960, and also reissue patent No. Re. 24731. The latter is a reissue of patent No. 2,782,936 (hereafter referred to as ’936); the original patent ’936 was issued on February 26, 1957 and the reissue on November 3, 1959.

In the complaint the plaintiffs charged that the defendant Langendorf United Bakeries, Inc, was infringing patent ’535. Thereafter the defendant Banner Metals, Inc., the manufacturer of the device that was claimed to infringe, was permitted to intervene and was named as a defendant in the complaint. In their counterclaim for declaratory relief defendants asserted that plaintiffs claimed that they were also infringing Re. 24731 and asked for declaratory relief, both as to its validity and the validity of ’535, and as to infringement of both patents.

In a…