Unipat Ag

Hydro-thoma Limited

Other

Christian Helmut Thoma

George Duncan McRae Arnold

An apparatus for heating a liquid comprising a housing having an internal chamber and a rotor disposed in said chamber. A drive shaft rotatably supported in the housing and extending into said chamber for imparting mechanical energy to the rotor. The rotor having a generally hemi-spherically shaped form and provided with a series of openings. A fluid intake passage in said housing preferably arranged to be nearer the rotational axis of the rotor and a fluid exit passage preferably positioned radially outwardly of said rotor.

Apparatus and method for heating fluids

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.

Hydrostatic transaxles

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.

Hydrostatic transmission with internal fluid expansion chamber

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. This construction allows for improved cooling of the power transmitting fluid flowing between the pump and motor and simplifies manufacture of the transaxle such that the bulk or all the machining operations can be carried out in only one of the three housing elements, this housing member being the smallest of the three which can be completed using a comparatively smaller sized CNC machining-center than would otherwise be the case. The two remaining housing elements may be used in an as cast or supplied condition.

Hydrostatic transaxle

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. This construction allows for improved cooling of the power transmitting fluid flowing between the pump and motor which, in the prior art, is difficult because the equivalent center section member carrying such passages is located within the axle assembly and is not exposed to an exterior surface over which cooling air from a fan driven input drive-shaft can pass.

Hydrostatic Transaxle

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. The pump is superimposed on the motor for compactness and the respective operational advantages that each type has is optimised for overall improved performance of the hydrostatic transmission.

Growing community of inventors

Jersey, Virgin Islands, British

Christian Helmut Thoma