Patents by Inventor Harry J. Hamilton

Harry J. Hamilton 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).

  • Pressure-release valve and conduit for preventing damage to seal of hydraulic power drive unit
    Patent number: 4903579
    Abstract: A hydraulic power drive unit for connection to the hydraulic system of an agricultural tractor is provided with a pressure release valve to protect the unit seal from damage if connected the wrong way round, and a bleed pipe which bursts to relieve pressure if the pressure release valve fails to operate.
    Type: Grant
    Filed: August 24, 1988
    Date of Patent: February 27, 1990
    Inventor: Harry J. Hamilton
  • Block for supporting the poles of equestrian fences
    Patent number: 4414920
    Abstract: A block (1) for use in supporting one end of an equestrian fence pole. Each face (2a,2a';2b,2b';2c,2c') of the block has a groove (3a,3a';3b,3b';3c,3c') for receiving one end of a pole. The three dimensions of the block (1) are all different so that a pole can be supported at three different heights.
    Type: Grant
    Filed: October 29, 1981
    Date of Patent: November 15, 1983
    Inventors: Peter K. Richards, Harry J. Hamilton
  • Block for use in supporting the pole of an equestrian fence
    Patent number: D270426
    Type: Grant
    Filed: June 3, 1981
    Date of Patent: September 6, 1983
    Inventors: Harry J. Hamilton, Peter Richards