Wilden Pump & Engineering Co., a Corporation v. Pressed & Welded Products Co., a Corporation

This case involves a device patented by the appellee, Wilden Pump and Engineering Company, and known as the “Wilden Pump.” The district court entered judgment against the corporate defendants, Pressed and Welded Products Company and other interrelated corporations, individual officers, and an employee Walcott, finding all liable for increased damages as willful infringers. We affirm the findings of validity and infringement of the patent but reverse the rulings that increased damages should be imposed and that Walcott should be held personally liable for the infringement.

The Wilden pump is an air actuated, diaphragm pump which is manufactured and sold by the appellee. It is typically used in dirty, sticky environments such as mines and oil refineries to pump a wide variety of materials. This litigation centers not upon the entire pump, but upon the pump’s actuator valve: a piston device providing the driving force for operation of the pump itself. Because of the adverse conditions under which these types of pumps are employed, stalling of the actuator valve has been a problem. The improvement in question, comprised in claim 13 of the patent, can be simply described as the…