Patents by Inventor George Duncan

George Duncan 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: 6343471
    Abstract: An axle assembly for use in lawn tractors, pedestrian walk-behind mowers and snow blowers in the form of a housing having an internally disposed hydrostatic transmission and speed reducing gearing. An input shaft supported in the housing for driving a variable-displacement hydraulic pump of the hydrostatic transmission, and where the motor is drivingly connected through the speed reducing gearing to an output axle shaft or shafts. A mechanical differential disposed within said housing for applications requiring differential speeds of said axle output shafts. The housing being formed by three housing elements in which two are disposed adjacent one another on one side of a parting plane and the third one disposed on the opposite side of the parting plane. Of the two internal chambers formed by the three housing elements, one chamber contains the hydrostatic transmission and the other chamber contains the speed reducing gearing.
    Type: Grant
    Filed: April 3, 2000
    Date of Patent: February 5, 2002
    Assignee: Hydro-Thoma Limited
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Publication number: 20010010154
    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: Application
    Filed: March 23, 2001
    Publication date: August 2, 2001
    Applicant: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 6255338
    Abstract: The use of a calcium intracellular store inactivator for inhibiting cell growth is disclosed; for example, thapsigargin or a derivative may be used to inhibit intraocular lens cell growth. Formulations include an emulsion of the compound for coating an IOL, either ex vivo or in vivo.
    Type: Grant
    Filed: June 29, 1998
    Date of Patent: July 3, 2001
    Assignees: The University of East Anglia, The Norfolk & Norwich Health Care NHS Trust
    Inventors: George Duncan, Michael Wormstone, Peter Davies, Christopher Liu
  • Patent number: 6237332
    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: October 4, 1999
    Date of Patent: May 29, 2001
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 6231466
    Abstract: A hydrostatic transaxle axle assembly for a vehicle such as a grass mowing lawn or garden tractor comprising a lly disposed hydrostatic transmission having a variable-displacement hydraulic pump fluidly connected to a fixed-displacement hydraulic motor, the hhousing for an internaydraulic motor being connected by differential gearing to axle shafts supported in the housing. The housing is formed by at least three housing members, two of which are separable on a first parting-plane arranged to be perpendicular with respect to the longitudinal axes of the axle shafts. One or two of the housing members being provided with an opening to allow a portion of another housing members, called the radiator member portion to extend through, and where the extending portion contains within its internal structure a number of fluid power transmitting passages arranged for the purpose of fluidly connecting the hydraulic pump with the hydraulic motor.
    Type: Grant
    Filed: November 16, 1999
    Date of Patent: May 15, 2001
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 6226968
    Abstract: After a cutter of a tobacco harvester cuts each tobacco plant, the cut tobacco plant has its stalk penetrated by toothed elements on two chains on opposite sides of the cut tobacco plant to advance it to an elevated position. Just prior to being released by the toothed elements, the stalk of the cut tobacco plant has its butt end engage a ramp to retard its motion to tilt the cut tobacco plant. This results in the cut tobacco plant pivoting to fall by gravity as its leaves are engaged by wheels to advance the cut tobacco plant. The butt end of the stalk falls into an area of a continuously rotating disc so that the cut tobacco plant has a substantially horizontal orientation. The cut tobacco plant is then advanced by chains and cleats to a spearing mechanism where the cut tobacco plant is automatically loaded on a stick.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: May 8, 2001
    Inventor: George A. Duncan
  • Patent number: 6178746
    Abstract: An improved hydrostatic transmission useful as a speed changing device having a single output shaft or a pair of outwardly extending shafts for use, for example, in small vehicles such as lawn and garden tractors. The hydrostatic transmission output may be mechanically coupled to the wheel driving axle by a gear or chain drive, or alternatively may have such means included in the same housing package containing the hydrostatic transmission. When a differential action is needed between the drive wheels of the vehicle, the differential may then also be included in the same housing package. In whichever of such configurations, the hydrostatic transmission comprises a radial piston pump fluidly coupled to a single or twin larger displacement axial piston motor of the swash-plate type by means of a fluid coupling valve supported by the housing.
    Type: Grant
    Filed: February 23, 1999
    Date of Patent: January 30, 2001
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 6076428
    Abstract: An axle assembly for use in lawn tractors, pedestrian walk-behind mowers and snow blowers in the form of a housing having an internally disposed hydrostatic transmission and speed reducing gearing. An input shaft supported in the housing for driving a variable-displacement hydraulic pump of the hydrostatic transmission, the pump fluidly coupled to a fixed-displacement hydraulic motor of the hydrostatic transmission, and where the motor is drivingly connected through the speed reducing gearing to an output axle shaft or shafts. A mechanical differential disposed within said housing for applications requiring differential speeds of said axle output shafts. The housing being formed by three housing members and joined together along a substantially planar and horizontally peripheral seam formed there between such that two of said housing members are to one side of said seam and join with the third housing element.
    Type: Grant
    Filed: October 6, 1998
    Date of Patent: June 20, 2000
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • Patent number: 6058704
    Abstract: A hydrostatic transmission having a housing for an internally disposed variable-displacement hydraulic pump and fixed-displacement hydraulic motor, a framework for supporting the hydraulic pump and motor components within said housing in a manner whereby the loads generated by the pressure medium flowing between pump and motor are absorbed into the framework. The framework to support a pintle-valve which as the fluid coupling means between pump and motor.
    Type: Grant
    Filed: March 20, 1998
    Date of Patent: May 9, 2000
    Assignee: Unipat AG
    Inventors: Christian Helmut Thoma, George Duncan McRae Arnold
  • 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
  • Patent number: 5400577
    Abstract: A tobacco harvester includes a plurality of linearly spaced tobacco plant engaging flights attached to an endless chain at equal linear distances with the sensing of a tobacco plant at a first position resulting in a cycle of operation occurring to advance the plant from its first position to a second position just beyond the front end of a spear. The plant is centered by an upper driven belt and a lower non-driven belt between which the plant is advanced by one of the flights. A paddle wheel is rotated 180.degree. during each advancement of a tobacco plant from its first position to its second position and aids in advancing the plant between the two centering belts. When another plant is sensed at the first position, the first tobacco plant is advanced from its second position to a third position on a stick at the rear of the spear.
    Type: Grant
    Filed: August 13, 1993
    Date of Patent: March 28, 1995
    Assignee: George A. Duncan
    Inventors: George A. Duncan, Billy L. Tapp
  • Patent number: 4508482
    Abstract: A support beam is formed of two wooden members held in spaced relation to each other by spaced blocks to provide openings to receive tobacco sticks with tobacco stalks thereon. Each end of the support beam has a longitudinal slot extending therethrough to enable a cable, which is attached to a rafter in the upper end of the barn, to extend therethrough. The lower end of each cable has a loop for attachment to a drum of a hoist mechanism, which has a portion bearing against the bottom surface of the support beam. The support beam has a depending projection spaced inwardly from each end to limit the outward movement of each of the hoist mechanisms. The drum of each of the hoist mechanisms is rotated separately to enable the support beam to be raised upwardly into the barn at an angle to clear rail supports on which the support beam is supported.
    Type: Grant
    Filed: February 25, 1983
    Date of Patent: April 2, 1985
    Assignee: University of Kentucky Research Foundation
    Inventor: George A. Duncan