Small differences do not preclude design patent infringement

Infringement was recently affirmed in an interesting design patent case where the defendant offered no prior art, nor proffered any jury instructions.  In Hafco Foundry and Machine Co., Inc. v. GMS Mine Repair and Maintenance, Inc., defendant GMS argued “the jury should have been instructed that ‘small differences between the accused and the claimed design’ will avoid infringement.” Such argument carried little weight as the Federal Circuit affirmed “the patented and accused designs need not be identical in order for design patent infringement to be found…. The controlling inquiry is how the ordinary observer would perceive the article.”  Not a revolutionary holding, but a good reminder of the value of design patents (and the importance of thorough lawyering).