Pfaff v. Wells Electronics, Inc.

Background

An individual inventor developed a new computer-chip socket and prepared detailed engineering drawings. He showed the idea to a large electronics company and accepted a written purchase order for 30,100 units before building a working prototype. He filed a patent application on April 19, 1982. A competitor later sold similar sockets and litigation followed over whether the inventor’s patent was valid because a sale or offer had occurred more than one year before his filing.

Reasoning

The Court addressed whether a commercial offer for sale can start the one-year deadline even if the inventor had not yet reduced the idea to a physical prototype. The Justices said the one-year rule applies when two things are true before the critical date: (1) there was a commercial offer for sale, and (2) the invention was ready for patenting. An invention is ready if it had already been reduced to practice or if the inventor had prepared drawings or descriptions so specific that a skilled person could make the product. Because the inventor had accepted the large purchase order and had provided detailed drawings, the Court concluded the deadline had begun and the patent was not timely.

Real world impact

The decision makes clear that taking commercial orders or otherwise marketing a new product can start the patent clock even without a prototype if the invention is sufficiently described. Inventors and companies must file earlier or keep plans confidential until they file. The ruling preserves room for genuine experimental testing but warns that routine commercial marketing can cost patent rights.