Great A. & P. Tea Co. v. Supermarket Equipment Corp.

Supermarket (plaintiff), assignee of a patent for a widely used device that separated customers' grocery orders on a checkout counter, sued Great A&P (defendant) for infringement; both lower courts upheld the patent's validity, relying on the invention's commercial success and the long-felt need it addressed, even though every individual component of the device (apart from a counter extension) was already well known in the art.