Exhausted combination doctrine

The exhausted combination doctrine, also referred to as the doctrine of the Lincoln Engineering case, is the doctrine of U.S. patent law that when an inventor invents a new, unobvious device and seeks to patent not merely the new device but also the combination of the new device with a known, conventional device with which the new device cooperates in the conventional and predictable way in which devices of those types have previously cooperated, the combination is unpatentable as an "exhausted combination" or "old combination". The doctrine is also termed the doctrine of the Lincoln Engineering case because the United States Supreme Court explained the doctrine in its decision in Lincoln Engineering Co. v. Stewart-Warner Corp.