Metallizing Engineering Co. v. Kenyon Bearing and Auto Parts 153 F.2d 516 (2d Cir. 1946) Meduna, (who worked for Mettallizing) invented a new process for reconditioning metal parts. Mettallizing began using the process to recondition the machine parts of their customers, but kept the equipment and the process a secret. They made a deliberate effort to keep the process a trade secret. More than a year later, they applied for, and received a patent on the process. Some times after that, Kenyon began using a similar process and Mettallizing sued for copyright infringement. Kenyon argued that the patent was invalid because the process was in public use for more than a year before being patented. Patent law (now 35 U.S.C. §102(b)), says that you can't patent something that was in public use, with the consent and allowance of the inventor, for more than one year prior to his application. Mettallizing argued that the process wasn't in public use, it was a secret process and no one in the public could have figured out the process just by looking at the reconditioned parts of Mettallizing's customers. That's known as a non-informing use. The Trial Court found for Mettallizing. Kenyon appealed. The Trial Court found that Mettallizing's use was not a public use, but a secret use, and that did not invalidate the patent. The Appellate Court reversed and found the patent invalid. The Appellate Court found that just using the process commercially (as Mettallizing was doing) counted as a public use, and that invalidated the patent. "That it is a condition upon an inventor's right to a patent that he shall not exploit his discovery competitively after it is ready for patenting; he must content himself with either secrecy, or [a patent]." The Court noted that if a third-party had invented the same process, but was working in secret, then that would not invalidate an inventor's patent. §102(b) is only applicable if the inventor himself is profiting off the invention (as what happened here). Of course, the risk of just keeping it a trade secret is that some other inventor could independently come up with the idea and patent it out from under you. The Public Use Exception is important because the US has a "first to invent" patent system. If the exception didn't exist, then a person could invent something, sell it all over the place, and then only apply for a patent once a competitor started copying it. Since no competitors would copy the product knowing that the inventor could patent it at any time, the inventor's monopoly would be indefinitely extended.