Abstract: In a hydrostatic device using an axial piston pump, a return plate is mounted so that it contacts the movable swash plate of the hydrostatic transmission. The plate is biased by a spring-type mechanism to force the swash plate to return to neutral, and the set position of the plate may be externally adjusted. A bias arm comprising a generally U-shaped member having spring mounted on either leg thereof may be engaged to the return plate.

Abstract: A hydraulic transmission having a hydraulic pump, a hydraulic motor and a center section having a pump running surface on which the hydraulic pump rotates and a motor running surface of which the hydraulic motor rotates. The center section has porting by which the hydraulic pump and the hydraulic motor are in fluid communication wherein the porting terminates in a pair of equidistantly spaced, generally arcuate shaped openings. The pump running surface includes a plurality of generally v-shaped grooves extending from each of the ends of the generally arcuate shaped openings.

Abstract: A transaxle comprised of a hydrostatic transmission mounted in a transmission housing and having a pair of hydraulic pumps and hydraulic motors operatively connected together through a center section mounted in the housing. First and second axle housings are mounted on opposite ends of the transmission housing, with output axles mounted in the axle housings and connected to the respective hydraulic motors.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block. Pressure relief valves or neutral valves may be located in the motor port block.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block. The motor assembly may also include pressure relief valves or neutral valves in the motor port block and a brake assembly mounted in the port block or on the motor housing to provide braking for the output axle.

Abstract: A hydraulic motor assembly having a motor and gear reduction set mounted in a housing. A brake assembly may be mounted in the port block to provide braking for the output axle or it may be located externally to the axle housing portion of the assembly. The housing may be formed of separate components, including the external surface of the ring gear and the hydraulic motor port block.

Abstract: A hydrostatic transmission may be placed in a free-wheeling state by rotating a bypass actuator that lifts the motor from a motor running surface whereby hydraulic fluid flows into a transmission cavity. A bypass arm connected to the bypass actuator and to a bypass rod may be used to engage and disengage the bypass actuator via operation of the rod. Further, a bypass latch may be used to lock the bypass arm in an engaged position whereby the bypass actuator is engaged and the transmission is disengaged. The bypass latch arm is preferably linked to the brake pedal whereby actuation of the brake pedal disengages the bypass actuator through operation of the latching arm. The system may be designed to provide dynamic braking through transmission resistivity prior to application of a brake force to the axles or wheels by unlatching the bypass arm prior to actuating the brake arm.

Abstract: A differential lock mechanism for use in a vehicle and having a cam mechanism that may be actuated by the vehicle user. The cam mechanism transfers rotational movement to linear movement along the axis of the vehicle axles to move an engagement mechanism into or out of engagement with an axle bevel gear. The engagement mechanism is also engaged to and rotates with a differential carrier, and thus when it is in the engaged position, it locks the vehicle axles to rotate with the differential carrier.

Abstract: In a hydrostatic device using an axial piston pump, a return plate is mounted so that it contacts the movable swash plate of the hydrostatic transmission. The plate is biased by a spring-type mechanism to force the swash plate to return to neutral, and the set position of the plate may be externally adjusted to compensate for irregularities. A second plate may be used where necessary based on the arrangement of the return plate with respect to the pump cylinder block.

Abstract: A hydraulic transmission having a hydraulic pump, a hydraulic motor and a center section having a pump running surface on which the hydraulic pump rotates and a motor running surface of which the hydraulic motor rotates. The center section has porting by which the hydraulic pump and the hydraulic motor are in fluid communication wherein the porting terminates in a pair of equidistantly spaced, generally arcuate shaped openings. The pump running surface includes a plurality of generally v-shaped grooves extending from each of the ends of the generally arcuate shaped openings.

Abstract: A transaxle having a transmission housing forming a hydraulic sump and a hydrostatic transmission mounted in the sump. The hydrostatic transmission comprises a center section having hydraulic porting mounted therein and a pair of hydraulic pumps and hydraulic motors mounted on the center section. A first axle housing is mounted on one end of the transmission housing, and has a first output axle mounted therein and connected to one of the hydraulic motors and a second axle housing is mounted on the opposite end of the transmission housing, and has a second output axle mounted therein and connected to the second hydraulic motor. A vehicle incorporating a dual hydrostatic transaxle is also disclosed.

Abstract: A mechanism for bypassing the flow of hydraulic fluid in a hydrostatic transmission comprised of a hydraulic pump and a hydraulic motor in fluid communication through a center section. The mechanism includes a bypass actuator rod that is moved from a first position to a second position to thereby move a plate into the hydraulic motor to lift the hydraulic motor off of the center section. The bypass actuator rod may has a generally flat surface and an opposite arcuate surface wherein the generally flat surface of the bypass actuator is positioned adjacent to the plate in the first position and the arcuate surface of the bypass actuator engages the plate in the second position. When the bypass actuator rod is in the first position the hydraulic motor is in substantial sealed engagement with the center section.

Abstract: A hydrostatic transmission may be placed in a free-wheeling state by rotating a bypass actuator that lifts the motor from a motor running surface whereby hydraulic fluid flows into a transmission cavity. A bypass arm connected to the bypass actuator and to a bypass rod may be used to engage and disengage the bypass actuator via operation of the rod. Further, a bypass latch may be used to lock the bypass arm in an engaged position whereby the bypass actuator is engaged and the transmission is disengaged. The bypass latch arm is preferably linked to the brake pedal whereby actuation of the brake pedal disengages the bypass actuator through operation of the latching arm. The system may be designed to provide dynamic braking through transmission resistivity prior to application of a brake force to the axles or wheels by unlatching the bypass arm prior to actuating the brake arm.

Abstract: A mechanism for bypassing the flow of hydraulic fluid in a hydrostatic transmission comprised of a hydraulic pump and a hydraulic motor in fluid communication through a center section. The mechanism includes a bypass actuator rod that is moved from a first position to a second position to thereby move a plate into the hydraulic motor to lift the hydraulic motor off of the center section. The bypass actuator rod may has a generally flat surface and an opposite arcuate surface wherein the generally flat surface of the bypass actuator is positioned adjacent to the plate in the first position and the arcuate surface of the bypass actuator engages the plate in the second position. When the bypass actuator rod is in the first position the hydraulic motor is in substantial sealed engagement with the center section.

Abstract: A control device for hydrostatic apparatus is disclosed. One embodiment in the control device is optimized for use with a hydrostatic transmission having a casing. The control arm is movably mounted to the casing and frictional structure engages the control arm to resist rotational movement of the control arm. A spring may be used to bias a wedge into frictional relation with the control arm to resist rotation of the control arm. The wedge may also be secured with removable attachments.