In Tokyo Keiso Company, v. SMC Corporation, 2009 WL 59769 (Fed. Cir. 2009)the Federal Circuit has again relied on the Supreme Court’s decision in KSR in invalidating a patent for obviousness.
The plaintiff, Tokyo Keiso, is the owner of a patent that covers a volume flow meter that measures the volume of a fluid flowing through a pipe or measuring line. The patent describes the prior art devices as having two measuring heads, one on each end of the measuring line, and using an acoustic signal transmitted through the metal measuring line. The problem with the prior art devices was that the sound travelled faster through the metal than through the fluid, resulting in inaccurate measurements. The invention in Tokyo Keiso’s patent used a measuring line made of plastic, instead of metal, which caused the acoustic signal to travel more slowly through the plastic than the fluid and made the flow meter more accurate.