Patents by Inventor Dennis A. Rigstad

Dennis A. Rigstad 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).

  • Battery enveloping with foam
    Patent number: 4092386
    Abstract: A battery separator envelope is provided having two walls of battery separator connected together by a foam member. In a method, two walls of battery separator are secured on a mandrel by sandwiching the mandrel and the walls of battery separator in a jig. A foam bead is then extruded between the walls and the bead is tamped and squeezed to complete the final formation of the foam member. The apparatus includes the mandrel, jig, extruder and support for guiding the jig assembly past the extruder.
    Type: Grant
    Filed: July 9, 1975
    Date of Patent: May 30, 1978
    Assignee: W. R. Grace & Co.
    Inventor: Dennis A. Rigstad