Wyers v. Master Lock Co.

Philip Wyers and Wyers Products Group, Inc. (collectively, Wyers) (plaintiffs) held various patents for hitch pins used to attach trailers to vehicles for towing. Two patents (the barbell patents) covered a locking barbell-shaped pin with a removable sleeve that could increase the pin’s diameter, allowing the pin to be used with various sized hitches. Wyers also held a patent (the seal patent) for a pin that had a locking mechanism with an external seal that insulated the lock from contaminants. When Wyers sued Master Lock Company (defendant) for infringing the barbell and seal patents, Master Lock argued that all three patents were invalid because their claimed inventions were obvious. Regarding the barbell patents, evidence showed that prior art, namely the Chang and Johnson patents, had previously disclosed every part of Wyers’s claimed invention except for the size-adjusting sleeve. Additionally, prior art in the form of the Down patent had disclosed an optional sleeve to adjust the diameter of a different style of towing attachment. Master Lock therefore argued that the combined prior art rendered Wyers’s claimed invention obvious. Regarding the seal patent, Master Lock argued that every element of the claimed invention was previously disclosed in the Chang patent except for the external seal. Further, evidence showed that there were various existing patents for external seals on other types of locking devices. Consequently, Master Lock argued that the combined prior art rendered the seal patent’s claimed invention obvious. In response, Wyers argued the prior art did not prove obviousness because (1) not all the prior art constituted analogous art and (2) an ordinary person would not have been motivated to combine the respective elements from the prior-art references. The district court held in Wyers’s favor, holding that the inventions were not obvious, the patents were valid, and Master Lock was liable for infringement. Master Lock appealed.