Abstract: A filled hydraulic piston assembly includes a piston body having first and second ends and a compartment in the piston body extending inwardly from the second end toward the first end. The piston is filled with an insert element which is inserted into the compartment of the piston and then held therein by pushing an annular lip on the second end of the body inwardly and against the adjacent end of the insert element. The insert element is comprised of a material that is less dense than the material of the body but has a higher bulk modulus than hydraulic oil. Oil channels can be formed in a variety of shapes on or around the insert so that oil may flow through the filled piston. The piston insert element can be formed from a variety of materials, such as plastic, magnesium, aluminum or other nonferrous metals. The body is generally comprised of steel.

Abstract: A hydrostatic transmission having a hydraulic pump and motor for use in a vehicle, including a center section for mounting and operatively connecting the pump and motor, a rotatable output drive shaft engaged to the hydraulic motor, and a running surface and support members integrally formed with the center section to fully support the output drive shaft, and further including a thrust bearing mounted in a housing for the transmission to engage said hydraulic motor, where the thrust bearing is supported by the upper and lower casing sections of the housing.

Abstract: An integrated hydrostatic transmission has a housing comprised of two separable elements detachably joined together along a substantially horizontal parting plane. A hydrostatic transmission including a hydrostatic pump, a hydrostatic motor, and a center section is separately mounted within the housing. The center section comprises a generally L-shaped member having a hydrostatic pump and motor mounting surfaces thereon disposed at right angles to each other. A pair of fluid ports is on each of the mounting surfaces, and internal passageways are in the L-shaped member connecting each of the fluid ports on one of the mounting surfaces with one of said fluid ports being on the other of the mounting surfaces. The L-shaped member comprises first and second legs integrally joined and extending at right angles to each other, with the first leg normally extending in a horizontal direction, and the second leg normally extending in a vertical direction.

Abstract: An integrated hydrostatic transmission has a housing comprised of two separable elements detachably joined together along a substantially horizontal parting plane. A hydrostatic transmission including a hydrostatic pump, a hydrostatic motor, and a center section is separately mounted within the housing. The center section comprises a generally L-shaped member having a hydrostatic pump and motor mounting surfaces thereon disposed at right angles to each other. A pair of fluid ports is on each of the mounting surfaces, and internal passageways are in the L-shaped member connecting each of the fluid ports on one of the mounting surfaces with one of said fluid ports being on the other of the mounting surfaces. The L-shaped member comprises first and second legs integrally joined and extending at right angles to each other, with the first leg normally extending in a horizontal direction, and the second leg normally extending in a vertical direction.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: A hydrostatic transmission including a fluid pump and fluid motor mounted within a transmission housing, and a brake connected to the motor shaft. The housing includes upper and lower sections. The brake includes rotor and stator plates, and a pin for urging the rotor and stator plates into frictional engagement. The upper and lower sections are joined along a split line and each has a mating half-round section, for positioning the pin.

Abstract: A center section for a hydrostatic transaxle has a generally L-shaped member having a hydrostatic pump and motor mounting surfaces thereon disposed at right angle to each other. The L-shaped member has first and second legs at right angles to each other with the pump and motor mounting surfaces thereon.

Abstract: A hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles has an L-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, and is mounted within the housing. The center section has passages and ports which are interconnected by certain passages and which are located whereby the center section may be cast. The center section has hydraulic pump and motor mounting surfaces on legs extending at right angles to each other.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: A hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles has an L-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, and is mounted within the housing. The center section has passages and ports which are interconnected by certain passages and which are located whereby the center section may be cast. The center section has hydraulic pump and motor mounting surfaces on legs extending at right angles to each other. The pump has a vertical input shaft extending through the housing and an axis of rotation at right angles to a housing parting plane.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel apparatus for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient apparatus for braking the transaxle, an improved apparatus for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission. Also, an apparatus is provided for diverting the hydraulic fluid to a sump by lifting a cylinder block from a running surface of the hydrostatic transmission to quickly drain the fluid.

Abstract: An improved hydrostatic transmission for use in a transaxle comprising a means for mechanically diverting hydraulic fluid from the hydraulic transmission to a sump to enable the vehicle to be moved with minimal resistance from the hydraulic fluid by unseating at least one of the hydraulic displacement units from its running surface to allow the fluid to drain quickly from the transmission to the sump, and an improved check valve mechanism on the center section of the transmission.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: An improved hydrostatic transmission which is compact, reliable and economical to manufacture, including a novel means for reducing the speed of the input to the transaxle using both hydraulics and mechanical gearing; an improved differential which is stronger and less complicated than prior art designs; a more effective and efficient means for braking the transaxle, an improved means for hydraulically bypassing the hydrostatic transmission and a unique check valve arrangement for maintaining oil pressure within the hydrostatic transmission.

Abstract: An integrated hydrostatic transaxle having a common housing for a hydrostatic transmission and a pair of oppositely-extending differentially-connected axles to have the common housing provide a common sump therefor and with a specifically-shaped center section interconnecting the pair of hydraulic displacement units constituting the hydrostatic transmission. The center section is a unitary member separate from the common housing, with the exterior thereof exposed to the common sump. The center section has passages and arcuate ports which are interconnected by certain of said passages and which are located whereby the center section may be cast to minimize any machining required to finish the center section. Such casting can result in a porous center section with possible leakage from a passage having high pressure fluid.