Abstract: An on demand oil dispensing system for motor vehicles including an electric motor driving a gear pump having flow paths including an intake line connected to an oil reservoir and a discharge line having a manual shut-off valve at the end thereof and a pressure sensing switch positioned in the discharge line which cuts off power to the motor and pump when the pressure in the discharge line rises above a set level and a reverse flow check valve in the discharge line upstream of the pressure sensing switch.

Abstract: An automatic, hydraulically actuated, sequencing valve for use with a pair of hydraulic acutators (e.g. double acting hydraulic cylinders) includes a valve body having a cylindrical bore therein. Cam members at either end of the bore are engaged by pins on the ends of a cylindrical spool, thereby rotating the spool 30.degree. each time it engages one of the cam members. A third cam member incorporated into the spool alternately locks open one of a pair of check valves as said spool is pressure shifted between the two bore cam members. The third cam member operates a locking system which permits only one of the two hydraulic cylinders to operate at a time and in sequence.

Abstract: The present invention provides a proportional-flow electrohydraulic control which includes both an electrohydraulic valve (36) and an electronic control (382). The electronic control includes an offsetting circuit (622) and is effective to produce an effective driving voltage, for an electrical force-motor (52) of the electrohydraulic valve, that is pulse-width modulated and that is greater than a fixed proportionality to an input signal (410) by a manually adjustable offset voltage. The offset voltage may be adjusted to provide a null force that exactly balances a spring (129) which presses a valve spool (54) to an overlapped position; so that fluid flow is proportional to an input signal irrespective of the initial load of the spring. Or, the offset voltage may be adjusted to provide a basic flow voltage; and then the rate of fluid flow that is delivered by the valve is greater than a given proportionality to the input signal by a substantially constant rate of fluid flow.

Abstract: An automatic horsepower control system on a working vehicle which varies the vehicle drive speed so as to maintain a maximum torque output on the working function of the vehicle. The prime mover of the vehicle drives the work function and also a pump which in turn supplies motordriven wheels for moving the vehicle. A stroker control cylinder controlled by a solenoid operated valve varies the pump flow rate to the motor to change vehicle speeds, said solenoid operated valve being signaled by an electronic controller which compares the prime mover's RPM with a standard to determine the torque load from the work function, and accordingly signals the valve to increase or decrease the flow to the motor to adjust vehicle speed and maintain a constant work load on the prime mover.

Abstract: The present invention provides an electrohydraulic control, which includes both an electrohydraulic valve (36) and an electronic control (382). The electronic control includes an offsetting circuit (622) and is effective to produce an effective driving voltage, for an electrical force-motor (52) of the electrohydraulic valve, that is pulse-width-modulated and that is greater than a fixed proportionality to an input signal (410) by a manually adjustable offset voltage. The offset voltage may be adjusted to produce a null force that exactly balances a spring (129) which presses the valve spool (54) to an overlapped position; so that fluid flow is proportional to an input signal irrespective of the initial load of the spring.

Abstract: A fluid control system for actuating a conventional power steering unit including a priority valve. The priority valve includes an inlet chamber connected to a pressure source, a priority outlet chamber connected to the steering unit, and a secondary outlet chamber connected to a secondary motor. The priority valve includes a valve spool slidable in a bore. One end of the bore with the spool forms a servo chamber which has a compression spring which urges the spool in one direction, and the other end of the bore and spool forms a servo chamber which acts in opposition to the first servo chamber. Each servo chamber is connected to the inlet pressure through an orifice in the valve spool which results in a rapid response time for moving the valve spool since the fluid travels only a short distance and since the fluid circulates it remains hot. There is a small logic control circuit flow across the priority valve and the steering valve for the steering unit.

Abstract: A load responsive system employing a fixed displacement pump and a variable displacement pump in a parallel circuit as a source of fluid in an open-center load sensing system. The load response control valve includes an unloading spool which is flow responsive in the operative positions of the control valve and maintains a constant .DELTA..rho. across the control valve by dumping the pump flow to reservoir; the control valve .DELTA..rho. being greater than the .DELTA..rho. of the pump compensator means so that the variable displacement pump will remain destroked until the system utilizes the full flow of the fixed displacement pump at which time the variable displacement pump strokes-out upon demand.

Abstract: An automatic horsepower control system on a working vehicle which varies the vehicle drive speed so as to maintain a maximum torque output on the working function of the vehicle. The prime mover of the vehicle drives the work function and also a pump which in turn supplies motor-driven wheels for moving the vehicle. A servo-control valve varies the pump flow to the motor to change vehicle speeds, said valve being signaled by an electronic controller which compares the prime mover's RPM with a standard to determine the torque load from the work function, and accordingly signals the valve to increase or decrease the flow to the motor to adjust vehicle speed and maintain a constant work load on the prime mover.

Abstract: A hydraulic auxiliary drive system for the normally non-driven wheels of a vehicle to assist the main wheels. The auxiliary drive comprises at least one variable displacement motor having a swash plate for driving at least one of the non-driven wheels, a variable displacement pressure compensated pump supplying the motor with a constant pressure regardless of vehicle speed, a spring for biasing each motor swash plate toward zero displacement, a servo connected to the motor swash plate for varying the displacement of the motor, and a pressure source for supplying the servo. A manually operated pressure control includes a solenoid-controlled variable orifice for controlling the pressure level supplied to the servo to vary the torque output of the normally non-driven wheels. A control valve is positioned between the pump and motor for disengaging and reversing the auxiliary drive. Another embodiment includes a second servo connected to the motor swash plate for decreasing the motor displacement.

Abstract: An electro-hydraulic auxiliary drive system providing power to the non-driven steerable wheels of an agricultural tractor utilizing hydraulic power in a parallel circuit from a pressure compensated pump which varies torque supplied to the auxiliary system by sensing the relative speed between the front and rear wheels and increases the torque to the auxiliary system when a set percentage of slip is determined between the front and rear wheels. The steerable wheels are driven by hydraulic motors connected in parallel through a flow divider valve and supplied by a variable displacement pressure compensated pump. When the electronic control receives an indication of slip from the main drive wheels it energizes a solenoid causing the pressure compensation level of the variable displacement pump to increase the torque output of the auxiliary drive system, with the percentage of slip being proportional to the increased torque.

Abstract: A hydrostatic parallel circuit drive system on a vehicle which drives a pair of hydraulic wheel motors which are supplied by a single pump source through a divider valve which senses the flow rate to each of the motors, and when the flow rates to the two motors vary sufficiently, the divider valve restricts the excess flow so that one wheel cannot spin and consume the entire flow to the system.