Patents by Inventor George Duncan McRae Arnold
George Duncan McRae Arnold 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).
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Patent number: 6884195Abstract: 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: GrantFiled: June 18, 2003Date of Patent: April 26, 2005Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6875147Abstract: An axle assembly has an internally disposed hydrostatic transmission and speed reducing gearing. An input shaft supported in the housing drives a variable-displacement hydraulic pump, the pump fluidly coupled to a fixed-displacement hydraulic motor, and the motor drivingly connected through the speed reducing gearing to an output axle shaft. The housing being formed by three housing members and joined together along a substantially planar and horizontally peripheral seam formed therebetween such that two of the housing members are to one side of the seam and join with the third housing element. Two internal chambers formed by the three housing elements where one chamber contains the hydrostatic transmission and the other chamber contains the speed reducing gearing. A connecting shaft spanning between the chambers to provide the power transmission link between the hydrostatic transmission and the speed reducing gearing.Type: GrantFiled: June 6, 2003Date of Patent: April 5, 2005Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6796121Abstract: A hydrostatic transaxle axle assembly for a vehicle has the housing 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 is provided with an opening to allow a portion of one of the other housing members to extend through, and 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: GrantFiled: July 25, 2002Date of Patent: September 28, 2004Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6782699Abstract: A hydrostatic transaxle axle assembly for a vehicle has 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: GrantFiled: April 30, 2002Date of Patent: August 31, 2004Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6779421Abstract: A hydrostatic transmission and gear transmission located in the same or separate housings structures, and mechanically drivingly connected together by a power transmission shaft. That housing structure surrounding the hydrostatic transmission defining a first internal volume containing the hydrostatic transmission components and providing a receptacle for the hydrostatic fluid. That housing structure surrounding the gear transmission defining a gear compartment sump. As one example, the housing structure surrounding the hydrostatic transmission may further define a second internal volume to operate as an overflow receiver for fluid transferred from the first internal volume. A duct operating in accordance with the siphon principle connects the internal volumes and where a pressure restriction valves ensures an above ambient pressure level in the volumes when the hydrostatic and gear transmission is operating. Alternatively, the gear compartment sump may act as the second internal volume.Type: GrantFiled: May 29, 2003Date of Patent: August 24, 2004Assignee: Hydro-Thoma LimitedInventors: George Duncan McRae Arnold, Christian Helmut Thoma
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Publication number: 20030216208Abstract: 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: ApplicationFiled: June 18, 2003Publication date: November 20, 2003Applicant: HYDRO-THOMA LIMITEDInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20030199354Abstract: 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 therebetween such that two of said housing members are to one side of said seam and join with the third housing element.Type: ApplicationFiled: June 6, 2003Publication date: October 23, 2003Applicant: HYDRO-THOMA LIMITEDInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20030192402Abstract: A hydrostatic transmission and gear transmission located in the same or separate housings structures, and mechanically drivingly connected together by a power transmission shaft. That housing structure surrounding the hydrostatic transmission defining a first internal volume containing the hydrostatic transmission components and providing a receptacle for the hydrostatic fluid. That housing structure surrounding the gear transmission defining a gear compartment sump. As one example, the housing structure surrounding the hydrostatic transmission may further define a second internal volume to operate as an overflow receiver for fluid transferred from the first internal volume. A duct operating in accordance with the siphon principle connects the internal volumes and where a pressure restriction valves ensures an above ambient pressure level in the volumes when the hydrostatic and gear transmission is operating. Alternatively, the gear compartment sump may act as the second internal volume.Type: ApplicationFiled: May 29, 2003Publication date: October 16, 2003Applicant: HYDRO-THOMA LIMITEDInventors: George Duncan McRae Arnold, Christian Helmut Thoma
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Patent number: 6626065Abstract: A hydrostatic transmission and gear transmission located in the same or separate housings structures, and mechanically drivingly connected together by a power transmission shaft. That housing structure surrounding the hydrostatic transmission defining a first internal volume containing the hydrostatic transmission components and providing a receptacle for the hydrostatic fluid. That housing structure surrounding the gear transmission defining a gear compartment sump. As one example, the housing structure surrounding the hydrostatic transmission may further define a second internal volume to operate as an overflow receiver for fluid transferred from the first internal volume. A duct operating in accordance with the siphon principle connects the internal volumes and where a pressure restriction valves ensures an above ambient pressure level in the volumes when the hydrostatic and gear transmission is operating. Alternatively, the gear compartment sump may act as the second internal volume.Type: GrantFiled: May 15, 2001Date of Patent: September 30, 2003Assignee: Hydro-Thoma LimitedInventors: George Duncan McRae Arnold, Christian Helmut Thoma
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Patent number: 6607462Abstract: 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 therebetween such that two of said housing members are to one side of said seam and join with the third housing element.Type: GrantFiled: February 11, 2002Date of Patent: August 19, 2003Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6564550Abstract: A hydrostatic transaxle axle assembly for a vehicle has 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: GrantFiled: April 30, 2002Date of Patent: May 20, 2003Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20020189251Abstract: 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: ApplicationFiled: July 25, 2002Publication date: December 19, 2002Applicant: HYDRO-THOMA LIMITEDInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20020173398Abstract: A hydrostatic transmission connected by means of a power transmission shaft to a speed reducing transmission, the housing structure surrounding said transmissions defining a first and second internal volumes. The first internal volume providing a receptacle for the hydrostatic fluid and for containing the hydrostatic transmission components. The second internal volume, which may or may not contain the gear train components, operates as an overflow receiver for fluid transferred from the first internal volume. A duct disposed in the housing provides the only flow path between the volumes and any fluid volume change in the first internal volume due to temperature variation is translated in a change in depth in the overflow receiver. Preferably, the duct operates in accordance to the siphon principle and catering for fluid volume change internally is a significant improvement over current practice where reliance is placed on external paraphernalia to achieve this end.Type: ApplicationFiled: May 15, 2001Publication date: November 21, 2002Applicant: Hydro-Thoma LimitedInventors: George Duncan McRae Arnold, Christaian Helmut Thoma
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Publication number: 20020116923Abstract: 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: ApplicationFiled: April 30, 2002Publication date: August 29, 2002Applicant: HYDRO-THOMA LIMITEDInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20020115519Abstract: 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 therebetween such that two of said housing members are to one side of said seam and join with the third housing element.Type: ApplicationFiled: February 11, 2002Publication date: August 22, 2002Applicant: HYDRO-THOMA LIMITEDInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6427442Abstract: 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: GrantFiled: March 23, 2001Date of Patent: August 6, 2002Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6346059Abstract: 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: GrantFiled: April 17, 2000Date of Patent: February 12, 2002Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6343471Abstract: 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: GrantFiled: April 3, 2000Date of Patent: February 5, 2002Assignee: Hydro-Thoma LimitedInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Publication number: 20010010154Abstract: 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: ApplicationFiled: March 23, 2001Publication date: August 2, 2001Applicant: Unipat AGInventors: Christian Helmut Thoma, George Duncan McRae Arnold
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Patent number: 6237332Abstract: 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: GrantFiled: October 4, 1999Date of Patent: May 29, 2001Assignee: Unipat AGInventors: Christian Helmut Thoma, George Duncan McRae Arnold