Patents by Inventor David A. Ehrhardt

David A. Ehrhardt 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).

  • Refractory furnace covers and methods of constructing same
    Patent number: 8016259
    Abstract: Refractory furnace covers and methods for their construction are provided. A method includes providing a molding form base having a molding surface, providing an outer molding frame on the molding form base, and providing at least one inner molding member disposed across and dividing the molding surface into a first molding section and a second molding section. The inner molding member has a first molding surface and a second molding surface located adjacent to and facing the first and second molding sections, respectively, the inner molding member having a protrusion located along the length of the first molding surface. A first molded section of the furnace cover is cast between the outer molding frame and the first molding surface of the inner molding member, the inner molding member is removed, and a second molded section of the furnace cover is cast between the outer molding frame and the first molded section of the furnace cover.
    Type: Grant
    Filed: November 9, 2005
    Date of Patent: September 13, 2011
    Assignee: Specialty Minerals (Michigan) Inc.
    Inventors: Robert A. Schneider, David A. Ehrhardt