Patents by Inventor David John Drake Hawkins

David John Drake Hawkins 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).

  • Manhole cover frames
    Patent number: 5769564
    Abstract: A spacer arrangement is provided for use in raising the height of a manhole cover frame, including one or more base spacer elements and one or more upper side extension elements; said one or more base spacer elements are adapted to be located within said manhole cover frame with said one or more side extension elements extending upwardly relative thereto; the spacer arrangement is adapted to receive a manhole cover; at least an underside surface of said one or more base spacer elements includes downwardly directed projections for stabilizing at least said one or more base spacer elements.
    Type: Grant
    Filed: May 8, 1996
    Date of Patent: June 23, 1998
    Assignee: CSR Limited
    Inventor: David John Drake Hawkins
  • Manhole cover frames
    Patent number: 5702200
    Abstract: A spacer arrangement is provided for use in raising the height of a manhole cover frame, including one or more base spacer elements and one or more upper side extension elements; said one or more base spacer elements are adapted to be located within said manhole cover frame with said one or more side extension elements extending upwardly relative thereto; the spacer arrangement is adapted to receive a manhole cover; at least an underside surface of said one or more base spacer elements includes downwardly directed projections for stabilising at least said one or more base spacer elements.
    Type: Grant
    Filed: May 8, 1996
    Date of Patent: December 30, 1997
    Assignee: CSR Limited
    Inventor: David John Drake Hawkins