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US 7,111,545 B1Granted
Return to neutral device for a hydraulic apparatus
AssigneeHydro-Gear Limited Partnership
InventorThomas J. Langenfeld
Life of this patent
Estimating the term…
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.
Claims25
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 having a first side and a second side, wherein the swash plate is pivotable about a first axis located generally between the first and second sides, the swash plate further having a neutral position and a plurality of stroked positions;
- a return mechanism having a set position and being capable of engaging the swash plate;
- a bias arm having a first end adjacent to the first side of the swash plate and a second end adjacent the second side of the swash plate, the bias arm engaged to the return mechanism to force the return mechanism to return to the set position;
- a first spring engaged to the first end of the bias arm;
- and
- a second spring engaged to the second end of the bias arm and extending generally parallel to the first spring.
4 more elements
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 having a first side and a second side, the swash plate further having a neutral position and being pivotable about a first axis between the neutral position, a plurality of forward stroked positions when the swash plate is rotated toward the first side thereof and a plurality of reverse stroked positions when the swash plate is rotated toward the second side thereof;
- a return mechanism engaging the swash plate, wherein the return mechanism is in a set position when the swash plate is in its neutral position, and a first portion of the return mechanism contacts the swash plate when the swash plate is rotated to one of its plurality of forward stroked positions and a second portion of the return mechanism contacts the swash plate when the swash plate is rotated to one of its plurality of reverse stroked positions;
- a bias arm engaged to the return mechanism to force the return mechanism to return to the set position;
- a first spring engaged to the bias arm at one end thereof and extending generally perpendicular thereto;
- and
- a second spring engaged to the bias arm at a second end thereof, where the second spring extends generally parallel to the first spring and is not coaxial thereto.
4 more elements
A hydrostatic device mounted in a housing, the device comprising
- a rotatable pump for transferring hydraulic fluid and having a plurality of pump pistons;
- an input shaft engaged to the pump, the input shaft having a longitudinal axis;
- 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 between a neutral position and a plurality of stroked positions;
- a return mechanism having a set position corresponding to the neutral position of the swash plate;
- a bias arm engaged to the return mechanism to force the return mechanism to the set position, wherein the bias arm comprises a cross member;
- and
- a first spring mounted on one end of the cross member and a second spring mounted on the second end of the cross member, where the ends of the cross member are on opposite sides of a plane that is parallel to both the longitudinal axis of the input shaft and the first axis.
4 more elements
A hydrostatic device mounted in a housing, the device comprising:
- a rotatable pump having a plurality of pistons;
- a swash plate adjacent to the pistons and adjustable between a neutral position and a plurality of stroked positions;
- and
- a return mechanism positioned to bias the swash plate into the neutral position, the return mechanism comprising:
- a first member engaged to the swash plate;
- a spring support engaged to the first member, the spring support having a first portion extending generally parallel to an edge of the swash plate when the swash plate is in the neutral position;
- a first end of a first spring supported at a first location on the spring support;
- and
- a first end of a second spring supported at a second location on the spring support, wherein the second spring is generally parallel to and offset from the first spring and the second location is separated a distance from the first location along the first portion of the spring support.
6 more elements
A return to neutral mechanism for a swash plate, comprising:
- a swash plate bias portion contacting the swash plate in two locations when the swash plate is in neutral;
- and
- a spring assembly contacting the swash plate bias portion and comprising a first spring, a second spring parallel to and laterally offset from the first spring, and a spring support extending from the first spring to the second spring and having a first portion extending into the first spring and a separate second portion extending into the second spring.
A hydrostatic device mounted in a housing, the device comprising:
- a rotatable pump including a plurality of pistons;
- an input shaft driving the rotatable pump, the input shaft having a longitudinal axis;
- a swash plate engaged to the pump pistons and rotatable about an axis between a neutral position and a plurality of stroked positions;
- and
- a return mechanism for forcing the swash plate to return to the neutral position, the return mechanism comprising a first member engaged to the swash plate, a second member engaged to the first member, a first spring located on the second member on one side of a plane that is parallel to the swash plate axis of rotation and the longitudinal axis of the input shaft, and a second spring located on the second member on the other side of said plane.
2 more elements
Dependencies are inferred from the claim text.