Patents by Inventor Duncan McRae

Duncan McRae 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).

  • Patent number: 6010311
    Abstract: A hydraulic reciprocating piston machine having a housing, a rotatable cylinder-barrel having a series of cylinders and each cylinder containing a piston which is operatively connected to a reaction member. The reaction member being urged by the forces created from those pistons subject to the pressure phase of the working cycle toward and against an abutment-member. The reaction member is purposefully provided with a limited freedom for movement with the housing, and the action of the pistons forces in urging the reaction member towards the abutment-member provides for a substantial reduction in the normal vibration of the reaction member without binding between the adjacent bearing surfaces.
    Type: Grant
    Filed: December 5, 1996
    Date of Patent: January 4, 2000
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold, Arthur Atholl Blair
  • Patent number: 5979270
    Abstract: A hydrostatic transaxle axle assembly for a vehicle such as a grass mowing lawn or garden tractor comprising a housing for an internally disposed hydrostatic transmission having a variable-displacement hydraulic pump fluidly connected to a fixed-displacement hydraulic motor, the hydraulic motor being connected by differential gearing to axle shafts supported in the housing. The housing is formed by three housing members, two of which are preferably separable on a parting plane coincident with the longitudinal axes of the axle shafts. One of the housing members being provided with an opening to allow a portion of one of the other housing members to extend through, and where the extending housing member contains within its interior a number of internal fluid passages for fluidly connecting the hydraulic pump to the hydraulic motor.
    Type: Grant
    Filed: July 9, 1998
    Date of Patent: November 9, 1999
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 5651301
    Abstract: A radial piston hydrostatic machine having an outer housing structure comprising at least two housing elements connectable together along a parting-plane arranged perpendicular to the rotational axis of said drive-shaft to define an internal chamber, a drive-shaft supported in the housing to drive the cylinder-barrel, the cylinder-barrel having a number of radial cylinders, each cylinder containing a piston such that the pistons can bear on the track-ring, fixed abutment means in the housing and disposed radially adjacent the track-ring for resisting the action of the pistons on the track-ring and suppressing vibration emanating from the track-ring.
    Type: Grant
    Filed: November 29, 1995
    Date of Patent: July 29, 1997
    Assignee: Unipat Aktiengessellschaft
    Inventors: Christian Helmut Thoma, Arthur Atholl Blair, George Duncan McRae Arnold