View source for Case 15: Metallizing Engineering Co., Inc. v. Kenyon Bearing & Auto Parts Co., Inc. (1946)

The patents covers a process in which metal is treated so as to bond more effectively with a spray metal (metal in a molten form) designed to build up the surface of worn machine parts. The previous method involved increasing surface roughness by machining methods; the new method builds upon a process from a previous patent in which an electric current heated an electrode and melted it into cavities in the metal. The surface was then smoothed by a peening hammer to restore the surface to its original finish. The new process employs the electrode process without smoothing the metal, thus creating a rough surface to which the spray metal bonds more easily. 

The district judge determined that the process was developed  for commercial, not experimental, purposes; as such, the use of the invention before the application was filed is not exempt from the "prior and public use" clause of USC 35-102. However, the use was determined to be secret; thus, the patent was valid under the code. This fell under the ruling of a previous case which the Appellate Court decided earlier; the court now determined that the prior ruling was wrong.

The initial law said that the patent was invalid if it was "before known or used." The second patent law revised this statement to say that inventions "in public use or sale" with the inventor's "consent or allowance" were unpatentable. Later laws required that an invention had not been in public use or sale for more than two years prior to the patent application. The current law is that the invention had not been in public sale or use in the U.S. and for longer than one year. This prior use clause prevents the "retardation" of science by minimizing the exclusivity of a patent; in an earlier case, a hose had been marketed for seven years before the patent was filed. This would, in effect, create a 14-year stagnation period in which that science could not proceed any further. In short, "the inventor who designedly, and with the view of applying it indefinitely and exclusively for his own profit, withholds his invention for the public, comes not within the policy or objects of the Constitution or acts of Congress." This applies even to a process by which a product is made; even if the product itself is sold, but the process is not revealed, the process still cannot be patented if in use before the application was filed.

In the previous ruling, the court had held that though the product of the machine was sold, the machine itself had not been revealed, and thus the patent was upheld. The ruling confused two principles: the inventor's right to profit from an invention and the contribution another person makes to the art in prior use. While an inventor may not have expressly abandoned his invention, he does forfeit his right to patent it if he allows too much time to pass during which it is open to the public.