Patents by Inventor Heinz Otto Dorst

Heinz Otto Dorst 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).

  • Warp resistant fire door
    Patent number: 3981102
    Abstract: A warp resistant fire door structure is disclosed, which includes a frame and a pair of front and back panels mounted thereon. The panels are secured permanently to the frame only at points adjacent their lateral edges. At other points, the panels are heat releasably bonded to the frame to be able to expand and contract relative to the frame in the presence of ambient temperature extremes.
    Type: Grant
    Filed: July 22, 1974
    Date of Patent: September 21, 1976
    Assignee: Dover Corporation
    Inventors: Frank Stuart Harwood, Heinz Otto Dorst