Patents by Inventor Steven E. Spence

Steven E. Spence 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).

  • Safety air plug and extrusion apparatus using same
    Patent number: 4867669
    Abstract: A safety plug for an extrusion apparatus for extruding pipe is provided with a valve opening when its tether to the extrusion die breaks. The valve can be formed by a disk on a rod which is axially displaceable in a tubular body having a flange forming a valve seat for the disk of the rod. The rod is connected to the chain.
    Type: Grant
    Filed: October 24, 1988
    Date of Patent: September 19, 1989
    Assignee: American Maplan Corporation
    Inventors: Flavio R. Da Silva, Steven E. Spence, Robert F. Shamet
  • Triple-wall foam coextrusion apparatus
    Patent number: 4846648
    Abstract: A triple-wall foam coextrusion apparatus in which inner and outer layers of one synthetic resin material are coextruded with an intermediate layer of another synthetic resin material, and wherein the passages for the first material are inclined to the axis along which the second material is extruded around a spider to ensure uniform flow.
    Type: Grant
    Filed: December 31, 1987
    Date of Patent: July 11, 1989
    Assignee: American Maplan Corporation
    Inventors: Steven E. Spence, Robert F. Shamet, Flavio Da Silva, Horst Eigruber
  • Triple-wall foam coextrusion apparatus
    Patent number: 4731002
    Abstract: A triple-wall foam coextrusion apparatus in which inner and outer layers of one synthetic resin material are coextruded with an intermediate layer of another synthetic resin material, and wherein the passages for the first material are inclined to the axis along which the second material is extruded around a spider to ensure uniform flow.
    Type: Grant
    Filed: November 19, 1986
    Date of Patent: March 15, 1988
    Assignee: American Maplan Corporation
    Inventors: Steven E. Spence, Robert F. Shamet, Flavio Da Silva, Horst Eigruber