Supreme Court of the United States February 17, 1947, 70 and 71 (Edward Katzinger Co. v. Chicago Metallic Manufacturing Co.)

MR. Justice Black

delivered the opinion of the Court.

The question here is whether the defendant, in a suit to recover royalties only under a terminated patent license agreement containing price-fixing provisions, can challenge the validity of the patent despite a covenant in the license contract that he would not do so.