Patents by Inventor George D. M. Arnold
George D. M. 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: 5503535Abstract: A hydrostatic piston machine having a housing comprising two shells of a part-cylindrical form, the shells connectable together along a parting-plane in which the central axes of the drive-shaft and cylinder-barrel lie. Each housing element is provided with a number of semi-circular formations and recesses which form pockets or apertures when the housing shells are connected together to provide support surfaces for the working elements of the machine. A cylinder-barrel mounted within a chamber formed between the shells and is provided with a number of cylinders each containing a piston. Fluid-passageways are provided in the housing to receive and supply fluid to the pistons of the machine.Type: GrantFiled: November 28, 1994Date of Patent: April 2, 1996Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold, Arthur A. Blair
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Patent number: 5279185Abstract: A radial piston hydrostatic machine disposed in a housing, a drive shaft supported in the housing and connecting through bevel pinion and gear to transmit rotation of the shaft to a cylinder barrel. The cylinder barrel provided with generally radial cylinder bores supporting pistons and mounted to rotate on a stationary ported pintle valve fixed to said housing. The cylinder barrel having an axially extending projection to support the bevel gear in spaced relationship with the end of said cylinder barrel, the bevel gear rotating with said cylinder barrel and drivingly connected to said bevel pinion. Fluid bearing means provided on the outer cylindrical surface of said pintle valve to provide a pressure field under said axially extending projection in order to counter any deflection of said bevel gear.Type: GrantFiled: September 9, 1992Date of Patent: January 18, 1994Assignee: Unipat AGInventors: George D. M. Arnold, Christian H. Thoma
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Patent number: 5228366Abstract: A transaxle driving apparatus for a self-propelled vehicle such as a grass-mowing lawn tractor, the transaxle comprising a two-piece housing structure forming an internal chamber for encapsulation of a hydrostatic machine and associated reduction gearing. The hydrostatic machine may comprise in one form a single hydrostatic pump driven by an input shaft rotatably supported in the housing, and fluidly coupled to two hydrostatic motors. In a modified form, the hydrostatic machine may comprise two hydrostatic motors fluidly coupled to a pumping source remotely mounted outside the transaxle.Type: GrantFiled: November 26, 1991Date of Patent: July 20, 1993Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold, Arthur A. Blair
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Patent number: 5195933Abstract: A friction drive unit for use within a transaxle driving assembly in self-propelled vehicles such as grass-mowing lawn tractors, the transaxle comprising a two-piece housing structure forming a number of internal chambers for the encapsulation of the friction drive unit, associated reduction gearing and a mechanical differential. The friction drive may comprise as input members, a pair of driver wheels operatable against a larger driven disc wheel acting as the output member, such that only one driver wheel can be engaged to the driven wheel at any one time, and where the direction of vehicle motion depends on which one of the two driver wheels is in contact with the driven wheel. Each of the driver wheels is subjected to continuous rotation from an input drive shaft and are operatively displaced along the shaft by means of respective sliding yoke means. The output from the driven wheel is connected to the transaxle output shafts by means of high ratio gear reduction means.Type: GrantFiled: December 9, 1991Date of Patent: March 23, 1993Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 5090949Abstract: A transaxle housing is provided for a small-sized vehicle such as a grass-mowing lawn tractor and encloses an internally located hydrostatic transmission in association with speed reducing gearing and mechanical differential for reasons of compactness and simplicity of manufacture. The axle housing comprises two members connected together alone a parting plane to define a number of internal chambers, at least one chamber used to enclose the hydrostatic transmission and remaining chambers enclosing speed reducing gearing and differential. One housing element is provided with a vertical input shaft which is operatively connected through bevel gearing to a hydraulic pump, the pump mounted perpendicular and fluidly coupled to a hydraulic motor, the rotary axis of the hydraulic motor being coincident with the parting plane of the housing and parallel to the rotating axes of the half shafts of the transaxle.Type: GrantFiled: December 10, 1990Date of Patent: February 25, 1992Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 4979583Abstract: A rotary hydraulic piston transmission located within an axle housing is provided that includes reduction gearing and a mechanical differential for the purpose of compactness and simplicity of manufacture. The axle housing comprises two main elements which, when attached together, form internal cavities, one cavity expressly used for the hydraulic transmission which comprises a hydraulic pump and a hydraulic motor mounted on either side of a partition member, and where the partition member divides the cavity into an upper and lower chamber for location of the hydraulic pump and hydraulic motor, respectively. The remaining cavities contain the reduction gearing and mechanical differential, and where the cavity containing the hydraulic transmission is purposely segregated from the remaining cavities in order to prevent material worn from the gears from entering the oil chambers of the hydraulic transmission.Type: GrantFiled: July 1, 1988Date of Patent: December 25, 1990Inventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 4843818Abstract: A hydrostatic machine including a casing 1 containing a rotary member 12 having radial cylinders 20 each with a piston 21 engaging a track ring 23. Both input 6 and output shafts 7 are connected either hydraulically through the transmission rotary members 12 or mechanically through a bypass shaft 10 and clutch 50 for reducing machine heat losses. Hydraulic ram 106,110 assistance for cushioning out pressure transients when transmission power returns from mechanical to hydraulic. Internal oil ducts 72,80.90 included for providing further temperature control for the main internal transmission component parts 14.24 said ducts 72,80,90 feed from a auxiliary fluid pump 8,9.Type: GrantFiled: August 20, 1987Date of Patent: July 4, 1989Inventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 4686829Abstract: A rotary radial piston pump or motor has a cylinder barrel rotating on a fixed pintle with a fluid exit at the fixed end of the pintle and an inlet at the opposite free end. A fluid impeller boosts the pressure entering the inlet and a filter prevents dirt entering. When applied to a hydrostatic transmission with pump and motor on a common pintle a pair of opposed non-return valves admit make-up fluid at one end of the pintle and a pressure relief valve provides overload relief at the other end of the pintle.Type: GrantFiled: May 21, 1986Date of Patent: August 18, 1987Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 4635535Abstract: A hydraulic radial piston pump or motor comprises a rotary cylinder unit (20) mounted to rotate on a fixed pintle (25), the unit (20) having radial cylinder bores formed by cylinder sleeves (23) each housing a piston (40) connected by a ball joint (44) to a slipper (45) engaging a surrounding annular track ring (47). The unit (20) also includes a separately formed central sleeve (21) having ports (26) cooperating with ports (31,32) in the pintle, the pintle ports (31,32) and the sleeve ports (26) being elongated in a circumferential direction. The pintle has three parallel flow passages, two (28') of smaller diameter than the third (27'). The slippers (45) are held resiliently against the track ring (47) by a band (66) having windows (68) which fit the slippers, the band being of resilient material and split at one point. The cylinder unit (20) has a rounded external surface and is free to float in an axial direction which provides a self-centering effect.Type: GrantFiled: September 6, 1983Date of Patent: January 13, 1987Assignee: Unipat AGInventors: Christian H. Thoma, George D. M. Arnold
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Patent number: 4526064Abstract: A motion transmitting device incorporates a toothed wheel wherein each recess between any two consecutive teeth is a portion of an ovoid profile.The ovoid profiles of such toothed wheel interengaging with a series of ovoid holes formed on a datum plate indirectly through interconnecting meshing elements, thus providing motion-transmitting devices which may have multitooth engagement and thereby multitooth transmission of loads.Type: GrantFiled: January 26, 1984Date of Patent: July 2, 1985Assignee: Quadrant Drive B.V.Inventors: John C. Carden, Panayotis C. Dimitracopoulos, George D. M. Arnold