Experimental Use–A Fragile Shield Against The One-Year Deadline For Filing Your Patent Application

George Jakobsche
Patent Attorney, Sunstein Kann Murphy & Timbers LLP, Boston, MA USA

Experimental use is a judicial doctrine that may be invoked to delay the start of the one-year clock for filing U.S. patent applications. A recent court ruling suggests that inventors tread cautiously in relying on the doctrine. Ordinarily, a public use or sale of an invention made more than one year before a patent application is filed bars the inventor from obtaining a patent. “Experimental use” allows an inventor to engage in activities that would otherwise bar him from obtaining a patent under the public use bar, as long as the use is necessary for experimentation. If the activity qualifies as experimental, the inventor can refute a charge that the activity rendered the invention unpatentable.

In Clock Spring, L.P. v. Wrapmaster, Inc., the Federal Circuit rejected Clock Spring’s argument that a demonstration of its technology should be considered an experimental use and affirmed a judgment invalidating its patent for failure to satisfy the one-year deadline. Clock Spring had demonstrated its gas pipe repair invention to representatives of several gas transmission companies more than one year before filing its patent application, without obligations of confidentiality. Clock Spring argued that the demonstrations were experimental uses, thus exempt from the statutory bar.


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