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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

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.

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1. A hydrostatic device mounted in a housing, the device comprising:a rotatable pump including a plurality of pistons;a swash plate engaged to the pump pistons and pivotable about a first axis, the swash plate having a neutral position and a plurality of stroked positions;a return plate engaging the

1. A hydrostatic device mounted in a housing, the device comprising:a rotatable pump including a plurality of pistons;a swash plate engaged to the pump pistons and pivotable about a first axis, the swash plate having a neutral position and a plurality of stroked positions;a return plate engaging the swash plate and having a set position, the return plate being rotatable from the set position about a second axis that is perpendicular to the first axis;a bias arm engaged to the return plate to force the plate to return to the set position, the bias arm comprising a pair of legs extending generally perpendicular to the second axis and a cross member connecting the two legs; anda spring mounted on each leg.2. A hydrostatic device as set forth in claim 1, further comprising an adjustment mechanism to adjust the set position of the return plate.3. A hydrostatic device as set forth in claim 2, wherein the adjustment mechanism is accessible from outside the housing.4. A hydrostatic device as set forth in claim 2, further comprising a lock mechanism for locking the adjustment mechanism in place.5. A hydrostatic device as set forth in claim 1, wherein the housing comprises a plurality of mating features formed therein to locate the legs of the bias arm.6. A hydrostatic device as set forth in claim 1, wherein the swash plate is a cradle mounted swash plate.7. A hydrostatic device as set forth in claim 1, further comprising a center section on which the rotatable pump is mounted and a hydraulic motor mounted on the center section, wherein the center section comprises hydraulic porting formed therein to connect the pump to the motor.8. A hydrostatic device as set forth in claim 7, wherein the pump is mounted at a right angle to the motor.9. A hydrostatic device mounted in a housing, the device comprising:a rotatable pump including a plurality of pistons;a swash plate engaged to the pump pistons and pivotable about a first axis, the swash plate having a neutral position and a plurality of stroked positions:a return plate engaging the swash plate and having a set position, the return plate being rotatable from the set position about a second axis that is different from the first axis;a bias arm engaged to the return plate to force the plate to return to the set position, the bias arm comprising a pair of legs extending generally perpendicular to the second axis and a cross member connecting the two legs; anda spring mounted on each leg, wherein the housing comprises a main housing element and a cover secured thereto on a plane parallel to the second axis.10. A hydrostatic device as set forth in claim 9, wherein the cover comprises a plurality of recesses to locate the springs.11. A hydrostatic device mounted in a housing, the device comprisinga rotatable pump for transferring hydraulic fluid and having a plurality of pump pistons;an input shaft engaged to the pump;a movable swash plate engaged to the pump pistons for modifying the quantity of hydraulic fluid transferred by the pump, the swash plate being pivotable about a first axis;a return plate having a first end engaged to the swash plate by at least two contact points, the return plate being pivotable at a second end thereof about a second axis that is perpendicular to the first axis, the return plate having a set position; anda bias arm engaged to the return plate to force the return plate to the set position, wherein the bias arm comprises a pair of generally parallel legs connected by a cross member.12. A hydrostatic device as set forth in claim 11, wherein the set position corresponds to the neutral position of the swash plate.13. A hydrostatic device, mounted in a housing, the device comprising:a notatable pump including a plurality of pistons:a swash plate engaged to the pump pistons and pivotable about a first axis, the swash plate having a neutral position and a plurality of stroked positions;a return plate engaging the swash plate and having a set position, the return plate being rotatable from the set position about a second axis that is different from the first axis, wherein the return plate comprises a pair of engagement structures formed at a first end to engage the swash plate and the second axis of rotation is located at a second end of the return plate opposite to the first end;a bias arm engaged to the return plate to force the plate to return to the set position, the bias arm comprising a pair of legs extending generally perpendicular to the second axis and a cross member connecting the two legs; anda spring mounted on each leg.14. A hydrostatic device as set forth in claim 13, wherein the bias arm engages the return plate at a location between the first end and second end of the return plate.15. A hydrostatic device mounted in a housing, the device comprising:a rotatable pump for transferring hydraulic fluid and having a plurality of ump pistons;an input shaft engaged to the pump;a movable swash plate engaged to the pump pistons for modifying the quantity of hydraulic fluid transferred by the pump, the swash plate being pivotable about a first axis;a return plate having a first end engaged to the swash plate by at least two contact points, the return plate being pivotable at a second end thereof about a second axis that is perpendicular to the first axis, the return plate having a set position;a bias arm engaged to the return plate to force the return plate to the set positions wherein the bias arm comprises a pair of generally parallel legs connected by a cross member; anda rotatable motor and a center section mounted in the housing, wherein the rotatable pump and the rotatable motor are mounted on the center section at right angles to one another and the center section comprises hydraulic porting formed therein to connect the rotatable pump to the rotatable motor.16. A hydrostatic device comprisinga first hydrostatic transmission having a first rotatable pump and first rotatable motor mounted in a housing and a second hydrostatic transmission having a second rotatable pump and second motor mounted in the housing;a first movable swash plate engaged to the first pump for modifying the quantity of hydraulic fluid transferred thereby, the first swash plate being pivotable about a first axis;a second movable swash plate engaged to the second pump for modifying the quantity of hydraulic fluid transferred thereby, the second swash plate being pivotable about a second axis;a first return plate engaged to the first swash plate by at least two contact points, the first return plate being pivotable about a third axis that is different from the first axis and having a set position corresponding to the neutral position of the first swash plate; anda second return plate engaged to the second swash plate by at least two contact points, the second return plate being pivotable about a fourth axis that is different from the third axis and having a set position corresponding to the neutral position of the second swash plate.17. A hydrostatic device as set forth in claim 16, further comprising a first bias arm engaged to the first return plate to force the first return plate to return to its set position, the first bias arm comprising a first pair of legs extending generally perpendicular to the first axis and a first cross member connecting the two legs.18. A hydrostatic device as set forth in claim 17, further comprising a second bias arm engaged to the second return plate to force the second return plate to return to its set position, the second bias arm comprising a second pair of legs extending generally perpendicular to the second axis and a second cross member connecting the second pair of legs.19. A hydrostatic device as set forth in claim 18, wherein the third axis is perpendicular to the first axis.20. A hydrostatic device as set forth in claim 19, wherein the fourth axis is perpendicular to the second axis.21. A hydrostatic transmission as set forth in claim 16, further comprising a first adjustment mechanism to adjust the set position of the first return plate.22. A hydrostatic transmission as set forth in claim 21, further comprising a second adjustment mechanism to adjust the set position of the second return plate.23. A hydrostatic transmission as set forth in claim 16, wherein the first and second axes are collinear.24. A hydrostatic transmission as set forth in claim 23, where the third axis is parallel to the fourth axis.25. A hydrostatic device mounted in a housing, the device comprisinga rotatable pump for transferring hydraulic fluid and having a plurality of pump pistons;an input shaft engaged to the pump;a movable swash plate engaged to the pump pistons for modifying the quantity of hydraulic fluid transferred by the pump, the swash plate being pivotable about a first axis;a return plate having a first end engaged to the swash plate by at least two contact points, the return plate being pivotable at a second end thereof about a second axis that is different from the first axis, the return plate having a set position;a bias arm engaged to the return plate to force the return plate to the set position, wherein the bias arm comprises a pair of generally parallel legs connected by a cross member;a spring mounted on each of the legs; andan adjustment mechanism to adjust the set position of the return plate and a means for locking the adjustment mechanism in a single position.