To establish infringement all elements of a claim must be present in the accused device. See e.g., Parmelee Pharmaceutical Co. v. Zink, 285 F.2d 465, 469 (8th Cir. 1961); Robertson v. Holt Motor Co., 28 F. Supp. 452, 453 (D.Minn. 1939). Claim one describes a pacer with a heat energy source and a heat to electrical energy converter.