Deere + Company

Vickers, Inc.

Douglas M Durant

Larry M Delfs

Derek Malcolm Eagles

William E Crookes

Cristian J Felix

Ronald Lee Pratt

Uwe H Kugler

Bennie Joe Vaughn

Douglas W Nordquist

Peter William Backes

A two stage brake valve communicates fluid pressure to a brake mechanism. The brake valve has an inlet for receiving pressurized brake fluid from a pump, a reservoir port, a stepped bore and a stepped piston member comprising a larger diameter prefill piston and a smaller diameter high pressure piston. The stepped bore and the stepped piston form a high volume prefill chamber and a high pressure chamber. The high pressure piston has a metering groove which controls communication between the inlet and the brake mechanism. A bleed orifice is formed in the high pressure piston and communicates the high pressure chamber to an outer surface of the high pressure piston. The bleed orifice includes an annular bleed groove formed in an outer surface of the high pressure piston and a radial passage extending from the bleed groove to an interior of the high pressure piston. The bleed groove is positioned so that the bleed orifice is open to the reservoir port via the prefill chamber during initial piston movement, and closed upon movement of the high pressure piston a predetermined distance beyond the position wherein the metering groove is first communicated with the inlet.

Brake valve

Left and right two stage brake valves communicate fluid pressure to left and right brake mechanisms. Each brake valve has an inlet for receiving pressurized brake fluid from a pump, a reservoir port, a stepped bore and a stepped piston member comprising a larger diameter prefill piston and a smaller diameter high pressure piston. The stepped piston is movable away from a rest position to transfer fluid to the brake mechanism. The stepped bore and the stepped piston form a high volume prefill chamber and a high pressure chamber. The high pressure piston has a groove communicated with the brake mechanism, and the groove communicates with the inlet when the high pressure piston has moved a certain distance to transfer fluid from the high pressure chamber to the brake mechanism. The prefill piston has a sealing land and a second land on either side of a sealing ring which is slidable in the stepped bore. The sealing land sealingly engages the sealing ring when the prefill piston moves to transfer fluid from the prefill chamber to the brake mechanism. The sealing land is spaced apart from the sealing ring by a distance which is greater than the distance between the groove and the inlet when the stepped piston is in its rest position.

Brake valve with prefill chamber unloading

Left and right two stage brake valves communicate fluid pressure to left and right brake mechanisms, each brake valve having an inlet for receiving pressurized brake fluid, a reservoir, a stepped bore and a stepped piston. The stepped bore and the stepped piston forming a high volume prefill chamber and a high pressure chamber. A prefill drain valve communicates the prefill chambers to the reservoir only when pump pressure is available at the inlet and blocks communication between the left and right prefill chambers and between the prefill chambers and a reservoir when pump pressure is not available at the inlet.

Brake valve with prefill chamber unloading valve

A hydraulic system includes a hydraulic pump which provides pressurized fluid at an output port as a function of pressure in a load sensing port, a hydraulic reservoir, and a load pressure sensing line connected to the load sensing port. A solenoid operated implement control valve controls fluid communication to and from a hydraulic function such as a cylinder. A supply control valve has a first position wherein the reservoir is communicated with the load sensing port and a second position wherein the pump output port is communicated with the load sensing port. A spring urges the valve member to its first position, and a solenoid is energizable to move the valve member to its second position. The solenoid is energized when the implement control valve is activated so that the supply control valve communicates pump pressure to the load sensing port and the pump will operate at full capacity whenever the second hydraulic function is operated.

Supply valve arrangement for closed center hydraulic system

Selective control valve used to operate implements attached to a tractor

A female coupler can operate in both a push-pull and a lever-actuated connect/disconnect fashion. Double lock ball controlling ramp surfaces are provided around the receiving bore of the coupler to allow the lock balls of the coupler to withdraw from the receiving bore when the receptacle is moved either into or out of the housing. The coupler can be moved into or out of the housing by pushing the male coupler into or pulling it out of the female coupler, or by use of a lever-actuated cam. A piston-type flow-check valve is provided to open the male check ball and hold it open despite transient surges. This flow-check valve is hydraulically actuated. A bleed valve for the hydraulically actuated flow-check valve is activated to release the flow-check valve when the lever is actuated or when the receptacle is pushed into the housing, thereby reducing the force needed for coupling. The lever can bleed and activate a plurality of couplers simultaneously, whereby multiple couplers can be connected or disconnected simultaneously.

Growing community of inventors

Waterloo, IA, United States of America

Douglas M Durant