Patents by Inventor Donald Frederic Bishofberger

Donald Frederic Bishofberger has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6053391
    Abstract: A stir weld tool of the present invention is used to weld two pieces of metal together through frictional heating, plasticizing, mixing, and forging of the plasticized metal into a uniform weldment. The stir weld is accomplished by rotating the stir weld tool with a pin having at least one boss on its surface to create the mechanical friction in the metal in contact with the rapidly rotating pin. As the rotating pin travels along the weld joint, the plasticized metal of the work pieces is extruded to the back face of the pin while undergoing a mechanical stirring and forging from action imparted by the at least one boss on the surface of the pin, and while confined from above by the pressure exerted on the metal by a shoulder on the stir weld tool.
    Type: Grant
    Filed: May 14, 1998
    Date of Patent: April 25, 2000
    Assignee: Tower Automotive, Inc.
    Inventors: Robert James Heideman, Jason Winton Thomas Scott, Christopher Brian Smith, Thomas Michael Thessin, Brahmanpalli Narasimhamurthy Ranganathan, Donald Frederic Bishofberger