Abstract: A fluid pressure system includes a source of water pressure 12, a first fluid motor 27 actuated by the pressurized water, a variable displacement hydraulic pump 11, and a second fluid motor 14 actuated by hydraulic fluid from the pump. The pump includes a control device 20 having a control chamber for changing the displacement of the pump. A proportional valve 17 is hydraulically connected to the control chamber for changing the pressure in the control chamber. The proportional valve includes a housing 34, 35 and a diaphragm 36 dividing the housing into first and second chambers 39 and 41. The first chamber is connected to the first fluid motor, and the second chamber is connected to the pump inlet. The pump control chamber is hydraulically connected to the second chamber through a variable orifice, and the size of the orifice is changed in response to the pressure in the first chamber and first fluid motor.

Abstract: A positive displacement pump, especially a high-pressure piston pump, has a piston which is mounted for reciprocation within a pumping chamber. The piston is reciprocated by a drive including a crank, a first connecting link eccentrically mounted on the crank, a second connecting link articulated to the first connecting link and to the piston, and a control link connected to said first and second connecting links for pivoting about a common axis therewith and having a free end portion supporting a roller movable along and in contact with a curved cam surface. The roller is held in contact with the cam surface by a pivotally mounted support link.

Abstract: A displacement control system for a variable displacement pump comprising a charge pump; a cut-off control valve connected to the charge pump, the cut-off control valve including a valve body having a first and a second pump ports and an outlet port formed therein, the first pump port being connected to the charge pump and the second pump port being connected to the variable displacement pump, a sleeve mounted within the valve body, a pin slidably mounted within the sleeve, a spool slidably mounted within the sleeve, a cylindrical cap member fixedly secured to the valve body defining a spring chamber therein, and a spring disposed within the spring chamber for urging the spool toward connecting the first pump port with the outlet port; and a servo booster connected to the outlet port for controlling the displacement of the variable displacement pump.

Abstract: A displacement control system for a variable displacement pump comprising a charge pump; a first and a second actuators connected in parallel to the variable displacement pump; a cut-off control valve connected to the charge pump, the cut-off control valve including a valve body having a first and a second pump ports, a pressure port and an outlet port formed therein, the first pump port being connected to the charge pump, the second pump port being connected to the variable displacement pump and the pressure port being connected to the first actuator, a sleeve mounted within the valve body, a first and a second pins slidably mounted within the sleeve, a spool slidably mounted within the sleeve, a cylindrical cap member fixedly secured to the valve body defining a spring chamber therein, and a spring disposed within the spring chamber for urging the spool toward connecting the first pump port with the outlet port; and a servo booster connected to the outlet port for controlling the displacement of the variabl

Abstract: A hydraulic control device to vary the displacement of a hydraulic piston unit, such as pump or motor, in function of the operating pressure, is provided with a pilot-operated servo piston. The pilot system comprises a sensing piston responsive to the operating pressure actuating a pilot piston and a force exerting member acting at an angle to the direction of movement of the sensing piston, the sensing piston and force exerting member acting on a movable bearing. The pilot piston is hydraulically and the movable bearing mechanically, e.g. by a coupling lever, connected to the main piston.

Abstract: A fuel injection pump, especially for internal combustion engines, which includes a pump piston axially displaceable in a cylinder of a pump housing and operable by a cam of a camshaft through the intervention of a rocker. For controlling the quantity of the fuel to be injected, the circumference of the piston is provided with an oblique control groove for cooperation with a control bore in the cylinder. The rocker is pivotally connected to the pump piston and in spaced relationship to the piston is under the load of a spring determining the maximum injection pressure. Between the area where the spring acts upon the rocker and where the rocker is pivotally connected to the pump piston, the rocker is provided with a roller adapted to roll on the cam while the spring presses the rocker in fuel feeding direction against an abutment.

Abstract: A variable delivery pump has a pump control mechanism in a housing secured thereto for governing directional flow of fluid through the pump, the pump being adapted to be connected through a closed loop to a motor. A pressure compensating valve is provided in the housing for governing pressure output of the pump, and a pump control cylinder is provided for positioning a flow control cam of the pump in accordance with flow of fluid through the direction control valve and the pressure compensating valve. A cam plate is coaxially connected to a directional control rotatable valve spool of the direction control valve, the cam plate having an outer periphery that is continuously radially variable from a maximum radial point to a minimum radial point for either direction of rotation of the cam from the maximum radial point as the control spool is rotated in either direction from a normal position. The cam plate actuates a cam follower, which in turn actuates a slideable sleeve in the pressure compensating valve.

Abstract: A hydraulic control system for adjusting the displacement of a variable displacement pump or pumps as dictated by pump output pressure and input speed. Driven by the same prime mover as the pump or pumps is a charging pump which communicates with a restrictor adapted to create a differential in the output fluid pressure therefrom, which pressure differential is sensed by a sensing valve for providing a corresponding output fluid pressure. Servo control means provided to the variable displacement pump or pumps communicates with both the restrictor and the sensing valve for adjusting the pump displacement in response to the fluid pressures delivered therefrom. A flow metering valve assembly is connected in a bypass around the restrictor to permit the passage therethrough of the charging pump output fluid at a rate metered in accordance with the variable displacement pump output pressure.

Abstract: This automatic hydraulic cushioning device for cam plate positioning actuators on variable displacement, axial piston pumps eliminates the noise, vibration, and wear caused by hammering of the positioning actuator on the back plate when the actuator is close to full retraction. A supply of fluid under pressure, which is available at the back plate, is channeled to the cam plate positioning actuator. A valve in the actuator blocks off drainage of the fluid whenever the actuator is close to its fully retracted position. This retained fluid becomes a hydraulic stop and cushion for the actuator thus eliminating the hammering as well as the noise, vibration, and wear which results from the hammering.

Abstract: An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a discharge rate which corresponds to the speed of rotation of the drive. A throttle valve is located in a discharge conduit of the auxiliary pump, and the pressure of the control fluid upstream of the throttle valve controls the displacement of a slide valve between two positions thereof in one of which the control slide controls the variable-output pump toward increasing the output thereof, while in the other of such positions the pump is controlled toward a reduced output thereof. In addition to the pressurized fluid, which acts on the control slide with a first force, a spring is provided which acts on the control slide with a second force opposing the first force.

Abstract: A variable delivery hydraulic pump having at least one pilot plunger, an operating plunger for adjusting the displacement of variable control element, and a first and a second spool for controlling travels of the plungers towards the variable control element side so that a single pumping element may precisely, stably carry out the two pressure-two volume control of the pump.

Abstract: A hydraulic system has a pump whose outlet is connected to a load and which has a pilot port whose pressurization is proportional to the pressure at the outlet. A restriction is provided between the outlet of the pump and the load. A differential valve is provided connected to the conduit between the pump and the load to both sides of the restriction and serves to compare the difference between pressure upstream and downstream of this restriction with a set point so as to depressurize the pilot port of the pump when this difference exceeds the set point. Furthermore, another valve is provided which compares the pressure in the feed conduit downstream of the restriction through yet another set point and also serves to depressurize the pilot port when this downstream pressure exceeds the second set point.

Abstract: A pump control assembly for a variable displacement pump has a means connected to a spring for selectively adjusting the preload on the spring for selectively adjusting the minimum pump discharge pressure. An adjustable stop device is provided for selectively adjusting the maximum force exerted on the spring by a piston device which increases the load on the spring for increasing the pump discharge pressure in response to a load pressure signal exceeding a preselected pressure level.

Abstract: A multi-range pressure compensated fluid delivery system gives output flow over at least two pressure ranges. The system comprises a prime mover driven variable displacement pump having an inlet from a source of hydraulic fluid and a delivery outlet. A delivery circuit from the output has at least two work circuits selectively connected thereto. A first of the circuits is operable up to a first pressure and a second of the circuits is operable only up to a second lower pressure. An actuator system controls pump displacement responsive to a pressure applied thereto. A system selectively applies a first signal determined by the first pressure to the actuator system to adjust the operating pressure of the pump. A device reduces the first pressure to the second pressure responsive to connection of the second circuit to the delivery circuit to thereby decrease the maximum compensated pressure setting of the pump.

Abstract: A control arrangement for preventing overloading of a prime mover which drives a pump comprises a pair of hydraulically operating adjusting units operative for adjusting the volume of fluid discharged by the pump. The arrangement further comprises a negative-feedback stabilizing circuit connected to the adjusting units and to a multi-setting regulating valve. The stabilizing circuit is operative for causing the valve to regulate the operation of the pump by controlling the operation of the adjusting units in dependence upon the output pressure of the pump. In order to protect the prime mover when the loading thereof has reached a predetermined value, an overload signal is generated which actuates an over-ride device. The override device is operative in response to the overload signal to cause the valve to assume a setting such that the adjusting units decrease the quantity of fluid discharged by the pump so as to unload the prime mover.

Abstract: A fuel injection pump including a charge pump for delivering discrete pulses of high pressure liquid fuel sequentially to the several cylinders of an associated engine is provided with an angularly adjustable cam ring to control the timing of the pumping strokes. The position of the cam ring is controlled by an advance piston, the position of which is controlled by a hydraulic pressure correlated with engine speed. A load sensing piston, engageable with one end of the advance piston above a fixed amount of timing advance, is subjected to the pressure of the metered fuel down-stream of the metering valve which controls the quantity of fuel delivered by the pump to urge the advance piston in a direction to retard the timing of the pumping strokes to result in a timing control system in which the timing is more advanced at high speeds and light load than it is at high speeds and full load.

Abstract: A pump is provided with a regulating device which includes a valve and a motor. The motor operates on the pump to vary the capacity thereof. Movement of the motor is controlled by the valve which has a spool and a body. A feedback link is provided between the motor and the body so that movement of the motor due to a displacement of the spool moves the body to return the valve to neutral. Hunting of the transmission is thus reduced.

Abstract: A horsepower limiter control for an axial piston pump provides a simple adjustment for setting the maximum horsepower the pump can provide and automatically adjusts the product of working pressure and maximum pump displacement to maintain the set horsepower. The horsepower limiter control operates to reduce the displacement of the pump when working fluid pressure exceeds the setting of the sequence valve.

Abstract: An arrangement for pumping fluids includes at least one variable-output pump and a drive therefor. An auxiliary pump is also driven by the drive and discharges control fluid at a rate corresponding to the speed of rotation of the drive into a discharge conduit in which a variable flow-through cross-sectional area throttle valve is located. The pressure in the discharge conduit upstream of the throttle valve controls the displacement of a control slide between the two end positions thereof in one of which the control slide controls the variable-output pump so as to increase the output thereof, while in the other of such positions of the control slide the pump is controlled so as to reduce the output thereof. The throttle valve is responsive to the pressure in the discharge conduit, but can be arrested in any position thereof when the drive is overloaded so that the flow-through cross-sectional area thereof is fixed, which results in a decrease of output of the variable-output pump when the drive is overloaded.

Abstract: A variable delivery hydraulic pump having at least one pilot plunger, an operating plunger for adjusting the displacement of variable control element, and a first and a second spool for controlling travels of the plungers towards the variable control element side so that a single pumping element may precisely, stably carry out the two pressure-two volume control of the pump.

Abstract: A control valve arrangement for regulating a servo pressure which in turn controls the stroke of a variable displacement pump has a control element positioned by means of an operating pressure derived from the pressure at the pump outlet. A solenoid valve is operable to reduce the operating pressure and thereby to position the control element so as to cause the pump stroke to be reduced. Movement of the control element beyond a predetermined position in a pump stroke reducing direction opens a bypass connection which maintains a small cooling flow through the pump.

Abstract: The pump has a regulating element whose position is controlled by means of a first and second piston. The first piston is kept under pressure by the output pressure of the pump. The output side of the pump is also connected to a throttle valve which has a cross-section allowing fluid flow which varies as a function of pressure. The pressure difference created at the throttle valve output relative to the throttle valve input acts on a three-position three-port control valve which control the pressure on the second piston accordingly. The second piston has a larger diameter than the first piston.

Abstract: A piston pump having a housing and an angularly adjustable swash plate for controlling piston displacement and the flow of fluid discharged from the pump has improved control means for controllably positioning the swash plate in response to a modified load pressure signal.

Abstract: A hydraulic control device for protecting a drive from excess loading conditions includes at least one pump having adjustable members for controlling the quantity of fluid transported by the pump. A pressure-responsive control slide is mounted for movement relative to a housing and is moved towards respective positions, each of which corresponds to a normally loaded condition of the drive by a control pump which generates a pressure force which is indicative of the rpm of the drive at normally loaded conditions. The device further includes an arrangement for securing the control slide when the drive is subjected to loads in excess of the respective normally loaded conditions so that a valve member is permitted to move in response to excess loads relative to the control slide after the latter has been secured in said respective positions by the securing arrangement between switching positions in which the adjustable members are operative to adjust the quantity of fluid being transported by the pump.

Abstract: A piston pump having a housing and an angularly adjustable swash plate for controlling piston displacement and the flow of fluid discharged from the pump has control means for controllably positioning the swash plate in response to a load pressure.

Abstract: A servomechanism for pump capacity control includes an adjustable throttle of the "nozzle-gate" type formed with two operating slots communicating through two fixed throttles with duct, a source of supply feeding the duct, an input signal converter whose movable element is connected to the gate of the nozzle-gate throttle and a four-slot, five-line distributor whose control spaces are in communication through two fixed throttles with the duct of the source of supply, two operating slots being formed in the adjustable throttle, whereas its operating spaces communicate with the corresponding spaces of an actuating hydraulic cylinder. The latter is connected to the control element and, by a mechanical position feedback, to the gate. The mechanical position feedback is constituted by a bar which is linked to the movable element of the hydraulic cylinder and has a slanted surface. The slanted surface interacts with a spring-loaded pusher, whose springs act on the gate.

Abstract: A hydraulic machine is provided with a control for reducing the capacity of the machine when subjected to excessive pressure.A piston is slidable in a cylinder to define two chambers, the chambers being interconnected by a restrictive passage. One chamber is connected to the pressure line and the other chamber is connected to a relief valve so that in the steady state the pressure in each is equal. When the pressure reaches a predetermined level the relief valve opens and vents the other chamber. The passage prevents flow to the other chamber creating a pressure differential which causes the piston to move along the cylinder and operate the machine control to decrease the capacity thereof.

Abstract: Control valve assemblies are taught which can be inserted into or associated with a basic primary unit for causing such basic primary unit to perform with optimum performance characteristics as a pump or motor, and a master or slave unit, etc. The function that the basic primary unit performs depends upon the control valve assembly selected. In the preferred embodiment of the control valve assembly, there is provided a central coaxial probe which passes through a bore in the spool valve body and is reponsive to a signal which is in addition to the other signals being sensed by the control valve assembly.

Abstract: A pressure regulator for an adjustable pump has an adjustable member for regulating the amount of fluid delivered by the pump. The position of the adjustable member is adjusted by two pistons of different diameters acting from opposite sides of the adjustable member and in which pressure of the fluid delivered by the pump is directed through a passage controlled by a control valve to one of the cylinder bores in which one of the pistons is closely guided. The control valve is movable by the fluid pressure between a neutral position in which fluid from the pump is prevented from flowing into the cylinder bore of the one piston, and two working positions, in one of which fluid from the pump will flow to the cylinder bore of the one piston while part of the fluid will flow over a throttle to a space at atmospheric pressure, and in the other of which fluid will flow unthrottled from the cylinder bore of the one piston to the aforementioned space.

Abstract: A hydraulic power transmission and braking system for vehicles in which individual hydraulic wheel motors are connected through suitable control apparatus to a variable displacement hydraulic pump which is driven by an appropriate power source. The displacement of the pump varies automatically in response to hydraulic fluid pressure and flow rate requirements imposed by the vehicle operating conditions. The power transmission control apparatus automatically switches from the 4-wheel drive mode to the 2-wheel drive mode as the vehicle accelerates past a predetermined speed. The braking control system proportions the braking force applied to each of the hydraulic wheel motors in accordance with the load imposed on that wheel by the vehicle operating conditions.

Abstract: A hydraulic system including a variable-delivery pump and a pressure compensator having a spring load applied to one end of the compensator spool. Means are provided for applying a force to the other end of the compensator spool proportional to the pressure obtained from a variable pressure-dividing system connected between the pressure line and tank. This pressure dividing system may consist of a pair of restrictors at least one of which is adjustable. Alternatively, it may consist of a spring-loaded check valve between the pressure line and the compensator chamber and a restrictor from the compensator chamber to tank.

Abstract: The rotary piston pump of a hydrostatic transmission for automotive vehicles has a slide block which is shiftable by a plunger in the cylinder of a follow-up control. The plunger is biased against the slide block by pressurized fluid in a chamber of the cylinder and can be shifted under or against the fluid pressure in the chamber by a control valve wherein a reciprocable spool controls the flow of fluid to the chamber from the pressure outlet of the pump. The spool is shifted in response to changes in fluid pressure at the opposite sides of a flow restrictor installed in a conduit which is connected to the outlet of the pump whereby the spool seals the cylinder of the follow-up control from the tank and from the pressure outlet of the pump before the chamber of the cylinder receives pressurized fluid to thereby change the position of the plunger and slide block.

Abstract: A hydraulic control system includes a generating circuit for providing power to a work function. A driving apparatus operates the generating circuit. A control circuit is connected to the generating circuit and the driving apparatus for permitting delivery of power to the work function when the driving apparatus is operating up to a predetermined speed. The control circuit also stops delivery of power to the work function when the driving apparatus runs above the predetermined speed.

Abstract: A hydraulic control system includes a generating circuit for providing power to a work function. A driving apparatus operates the generating circuit. A control circuit is connected to the generating circuit and the driving apparatus for permitting delivery of power to the work function when the driving apparatus is operating up to a predetermined speed. The control circuit also stops delivery of power to the work function when the driving apparatus runs above the predetermined speed. The control circuit further includes a cut-off apparatus for stopping delivery of power to the work function when the driving apparatus is running up to the predetermined speed.