Abstract: The invention relates to a variable displacement pump supplying fluid to a number of consumers. The pump control for adjusting the delivery rate is actuated by a signal which is produced by the respective highest loaded consumer. The signal is provided by a valve, in particular a pressure compensating valve which is associated with the consumer, and which valve opens a spool land when the valve becomes positioned at its control end range. A pressure signal from any pressure fluid source is delivered through the land to the pump controller. The control, according to the invention, offers a broad variety of possibilities for arranging the pressure compensation valve at various locations, engaging the valve by a variety of pressure differences, and using a number of pressure fluid sources of provide for the signal pressure to actuate the pump controller.

Abstract: Disclosed is an arrangement that includes a piston cylinder unit having pressure chamber in which fluid acts in opposition to a spring piston combination, a pressure generator and a fluid conduit extending between a tank and the tank. A first and a second valve are connected in series between the pressure generator and tank with the pressure chamber being in fluid communication with the connection between the valves. In known arrangements of the above type there is dead play wherein not every control signal corresponds to a defined position of the piston in the cylinder. However as disclosed herein the setting accuracy is improved by a throttle in parallel with valve that is fluidly connected between the pressure chamber and the piston cylinder unit. Also third and fourth valves may be connected in series between the pressure generator and tank and have a fluid connection between the third and fourth valves to the unit pressure chamber that is opposite the first chamber to provide a bridging circuit.

Abstract: An actuator device for mechanisms located within a pressurized environment including a double acting piston and cylinder combination operating in the same environment. The motive power for the piston is provided by pressurized gas from the pressurized environment or from a substitute source, whereby complex and elaborate sealing systems are eliminated.

Abstract: An apparatus for supplying a pressure oil to a plurality of hydraulic cylinders of a working machine such as power shovels provided with working equipment such as shovels, wherein the cylinders are contracted at the same speed to move down or lower the working equipments at the same speed, so that the working equipment are prevented from suddenly dropping off in operation even if pressure oil passages (a, b) supplying the pressure oil to the cylinders are damaged during operation. The apparatus comprises: a lock valve assembly (B) provided with a valve housing (70) mounted on a cylinder tube of each of the hydraulic cylinders, in which valve housing (70) a check valve (77), a poppet valve (78) and a pilot valve (79) are mounted; and a directional control valve assembly (C) for selectively supplying the pressure oil to a lifting-movement pressure chamber (9a) and a lowering-movement pressure chamber (9b) of each of the hydraulic cylinders through the pressure oil passages (a, b), respectively.

Abstract: A hydraulically operated device including a single-acting cylinder having a piston for operating a working tool, a pressure chamber for applying a hydraulic pressure to the piston from an original position to an operated position, and a return spring for biasing the piston toward the original position. The device includes a hydraulic pump for delivering a pressurized fluid to be fed into the pressure chamber of the cylinder, and an automatic drain valve for inhibiting the pressurized fluid from being discharged from the pressure chamber while a difference by which a delivery pressure of the pump is higher than a pressure in the pressure chamber exceeds a predetermined value. When the difference becomes smaller than the predetermined value, the automatic drain valve is operated to allow the pressurized fluid to be discharged from the pressure chamber. Thus, the automatic drain valve automatically drains the pressure chamber when the pump is turned off.

Abstract: A method and apparatus for changing dies on a moving bolster for a press including a control circuit in combination with a cam-actuated deceleration valve. A ramp is located at a predetermined location along a path for the moving bolster. Upon reaching the ramp location when the bolster is moving toward the press, the deceleration valve is actuated to inhibit and shut off a flow of air to air-operated motors on the bolster. Thereupon, the moves to a stop at a predetermined location relative to the press.

Abstract: An industrial truck has a hydraulic fluid supply and at least one double-acting hydraulic cylinder assembly for moving a movable element of the vehicle. The cylinder assembly includes a cylinder having a fluid chamber therein, and a piston movable axially in the cylinder. An actuator rod extends from the piston for connection to the movable element. The piston divides the fluid chamber into a rod end chamber and a piston end chamber each having hydraulic fluid therein. A pair of two-way two-position poppet valves are selectively actuatable between a first joint state in which both of the valves are in a normally closed position in which the piston does not move; a second joint state in which a first one of the valves is closed and a second one of the valves is open to move the piston in a first direction; and a third joint state in which the first one of the valves is open and the second one of the valves is closed to move the piston in a second direction opposite to the first direction.

Abstract: An air spring apparatus has quick pressure release, and rapid air exhaust, capability by means of a relatively large diameter exhaust port in a larger, primary air spring which is controlled by the action of a smaller, secondary air spring. The secondary air spring is equipped with a check valve which controls the flow of air into the primary air spring. The rapid exhaust of the primary air spring is effected by triggering the removal of air pressure from the secondary air spring through a plurality of orifices in a centrally disposed guide tube which permits the collapse of the smaller air spring and the accompanying removal of a valve plate from a relatively large diameter exhaust port of the primary air spring.

Abstract: A pneumatic actuator comprising a housing asembly (1, 2) and a diaphragm (7) defining a diaphragm chamber (6) which is in communication with the exterior through an exhaust and a suction conduit (1c, 1d). Solenoid valves (8, 9a, 9b) for opening and closing the conduit (1c, 1d) are mounted to the housing (1) and are covered by an outer cover (10) attached to the housing (1). The housing (1) has a raised outer surface (1e) which is brought into contact with the cover (10) for substantially preventing ingress of moisture. The raised outer surface (1e) of the housing (1) also has a groove (13) for collecting and exhausting moisture passed through the clearance under the outer cover (1) by the capillary action.

Abstract: A metering valve adapted to operate a seat on a side of an actuator port by means of a poppet section of a main poppet arranged in a valve casing to selectively communicate the actuator port to a tank passage. The main poppet is formed with a pressure chamber on a side thereof opposite to the poppet section. The pressure chamber has a pressure receiving area substantially equal to that of the seat. Also, the main poppet is formed with a through-hole constantly communicated to the actuator port and a pilot chamber to which pilot pressure for moving the main poppet in a direction of opening the seat is applied. Thus, the metering valve is capable of stably accomplishing its control irrespective of a variation of pressure on the side of the actuator port.

Abstract: A drive for a steam servo valve (2), including a control valve arrangement for regulating the actuating pressure of a servo drive (1), whereby the drive can always be actuated reliably and quickly even with comparatively high oil pressure. This is achieved by the control valve arrangement having at least two regulatable control valves (17, 21) which are pressure-actuated via at least one pilot regulating valve (proportional pressure valve 29, 34).

Abstract: The flow of hydraulic fluid to and from an hydraulic elevator piston is controlled by a motor-actuated spool valve operated by a microprocessor. To lower the elevator, a main check valve is opened by a down piston using hydraulic fluid from the system. Pressure is equalized on both sides of the main check valve just before the latter is opened thereby allowing the use of a smaller down piston which uses less hydraulic fluid. This results in smoother car motion during descent of the car. The addition of a valve bleed passage to equalize pressure on both sides of the check valve also prevents rapid descent of the elevator car in the event that the spool valve were to be open at the time descent commences.

Abstract: A control system for a fluid operated jack reduces the speed of retraction of a piston rod of the jack to an acceptable rate during a preselected range of operation by adding pressurized fluid flow to the fluid being exhausted from the jack through a restrictor valve to the reservoir. This reduction in speed reduces the potential for damage to the jack and associated componentry without sacrificing efficiency of operation. An implement controller causes fluid flow from a fluid source to be combined with the flow of fluid being exhausted from the jack in response to receiving a position signal from a implement position sensor and subsequent to the implement controller commanding the shifting of a control valve to a position at which fluid flow is passed from the fluid operated jack to the reservoir. The control system is particularly suitable for use on an automatic guided vehicle.

Abstract: An actuator which is used, for example, to operate an internal combustion engine poppet valve is configured to open the poppet valve by means of a high pressure hydraulic fluid. This fluid powers the actuator piston and, at the same time, compresses air to accomplish both damping of the piston and conversion of the kinetic energy of piston translation into potential (pneumatic) energy. The actuator is held or captured in the second or valve-open position by a hydraulic latch and when released, is returned by the stored pneumatic energy to its initial position. Damping of the returning actuator piston is accomplished by a separate adjustable pneumatic orifice arrangement to assure gentle seating of the poppet valve.

Abstract: In a pilot operated control valve system provided with a plurality of valves for controlling a plurality of hydraulic devices such as hydraulic cylinders, there is employed a plurality of valves each of which does not interfere with each other in operation and requires a minimum mounting space in the system to enable the system to be a small system having a construction easily adapted to control a plurality of hydraulic devices and also adapted to simultaneously supply the pressure oil to the hydraulic devices from a pair of hydraulic pumps through the same hydraulic circuit as needs require.

Abstract: The invention concerns a method and apparatus for improving the performance of a motor-controlled hydraulic elevator, in which oil is pumped using an hydraulic pump controlled by an electric motor from a container via a main supply duct into a lifting cylinder to move the elevator upwards, and returned in a controlled manner through the pump into the container to move the elevator downwards. In order to improve the loading conditions of the motor during down-travel, the oil pressure in the main duct is reduced to a substantially predetermined constant level by means of a check valve or lowering valve which, to provide compensation for the pressure in the pump, has a feedback connection to the main duct via a pressure compensation valve which controls the volume of flow through the check valve or lowering valve.

Abstract: In a pilot operated control valve system provided with a plurality of valves for controlling hydraulic equipment such as hydraulic cylinders, there are employed a plurality of valves each of which does not interfere with each other in operation and requires a minimum mounting space in said system to enable said system to be a small-sized system having a construction easily adapted to control a plurality of hydraulic equipments.

Abstract: An energy saving vacuum/pressure regulator is installed between a pump and a load for the pump, such as a storage tank, and relieves the load on the pump when the fluid in the load has reached a desired pressure state. The pressure state can be either negative pressure, or positive pressure relative to the environment. The regulator relieves the pump automatically, so that the energy consumed during variable usage of the fluid is reduced.

Abstract: The invention concerns an apparatus for improving the performance of a motor-controlled hydraulic elevator, in which oil is pumped using an hydraulic pump controlled by an electric motor from a container via a main supply duct into a lifting cylinder to move the elevator upwards, and returned in a controlled manner through the pump into the container to move the elevator downwards. In order to improve the loading conditions of the motor during down-travel, the oil pressure in the main duct is reduced to a substantially predetermined constant level by means of a check valve or lowering valve which, to provide compensation for the pressure in the pump, has a feedback connection to the main duct via a pressure compensation valve which controls the volume of flow through the check valve or lowering valve.

Abstract: The flow of hydraulic fluid to and from an hydraulic elevator piston is controlled by a motor-actuated spool valve operated by a microprocessor. To lower the elevator, a main check valve is opened by a down piston using hydraulic fluid from the system. Pressure is equalized on both sides of the main check valve just before the latter is opened thereby allowing the use of a smaller down piston using less hydraulic fluid. This results in smoother car motion during descent of the car. The addition of a solenoid valve bleed passage to equalize pressure on both sides of the check valve also prevents rapid descent of the elevator car in the event that the spool valve were to be open at the time descent commences.

Abstract: In accordance with an illustrative embodiment of the present invention, an expansible chamber device includes a piston movable within a cylinder, a head on the cylinder having intake and exhaust ports, a normally-open intake valve for closing the intake port automatically when the flow rate or velocity of a working medium entering the cylinder reaches a predetermined value, variable restraining means for inhibiting closing of the intake valve in response to flow, an exhaust valve for preventing escape of working medium from the cylinder until cylinder pressure is reduced to a set level, spring means for opening the exhaust valve at that level, and means operable near the top-dead-center position of the piston for automatically opening the intake valve and for closing the exhaust valve to enable the cycle to repeat. A unique system for controlling the variable restraining means, as well as methods for regulating the flow or working medium through said valves, also is disclosed.

Abstract: In a pneumatic actuator wherein air pressure in a diaphragm compartment (38) is changed by controlling solenoid valves (39, 39 and 41) thereby to output a displacement; an intake solenoid valve (39) has a spring (30h) which penetrates a center part of a fixed iron core (39e) and urges a movable iron core (39f), and the solenoid valves (39, 39 and 41) are mounted on a housing (31) in a triangular disposition with terminal side thereof faced to the housing (31), and besides, one of terminals of each solenoid valve (39 or 41) is secured with each other at a center part of the triangular disposition, and the other terminals are disposed outward of the triangular disposition.

Abstract: A control system for a two way acting hydraulic servomotor wherein the servomotor is connected in the diagonal of a bridge circuit that includes four magnetic valves with a pair of the valves being normally open in a non-energized condition being connected to the one end of the servomotor and to the container and a second pair of the valves being normally closed in a deenergized condition being connected to the opposite end of the servomotor and to a pressure source. Circuitry provides pulse trains that are modulatable to control the operation of the magnetic valves and thereby the application of pressurized fluid to the opposite ends of the servomotor.

Abstract: A pneumatic constant-velocity running apparatus employing a diaphragm type actuator in which a portion or the whole of a control circuit for the actuator is made of a hybrid IC and the hybrid IC portion with a protector is fixedly mounted onto the outer surface of an housing of the actuator. The apparatus is made compact and further be remarkably improved in an operation accuracy and in noise-proof property as well as in heat radiating property.

Abstract: A vacuum operated actuator has a spring biased diaphragm that is exposed on one side to atmosphere and on the other side to a vacuum chamber. An output means is connected to move with the diaphragm and carries a valve means which together with a tube a manually controlled tube operates to connect the vacuum chamber with either atmosphere or with a vacuum source so that the diaphragm and thereby the output moves with the movement and in the direction of the tube so as to provide an output force so as to move the output with a force substantially greater than the input force applied to the tube.

Abstract: The invention relates to an examination apparatus with a mass balancing device. The balancing device comprises a compressed air cylinder which operates as a gas pressure operated spring. The internal pressure of the cylinder can be controlled, by a pressure control circuit in dependence of the sine of the pivot angle. A pressure control circuit is a control signal supplied by a sine generator. The sine generator generates a signal which is dependent on the sine of the pivot angle.

Abstract: In a steam generating plant having a main steam line and a pivotally actuated valve movable between open and closed positions for controlling the flow of steam in the main steam line, a system for operating the main steam line valve comprising a spring assembly for biasing the valve pivotally into the closed position, fluid actuated means for urging the valve pivotally into the open position against the biasing action of the spring assembly and means for supplying fluid under pressure for the fluid actuated means, the fluid supply means including a pump operatively connected to the fluid actuated means and at least one exhaust valve operatively connected to the pressure end of the pump.

Abstract: In hydraulic control devices comprising a two-way flow regulator in a resoir return passage, in which the flow regulator comprises a metering restriction and a pressure equalizer including a control piston with the piston ends disposed in control chambers and subjected to the action of control pressures, the actuation of a single-acting hydraulic motor under load often results in an unavoidable switching shock, because the displacement of the control piston involves the consumption of a certain volume of the pressure fluid. In order to eliminate the switching shock with a simple construction, the end of the control piston subjected to the action of the load pressure is formed as a closure element cooperating with a valve seat in the manner of a poppet valve for holding the load pressure.

Abstract: Disclosed is a pressure actuator such as a vacuum actuator comprising a valve unit including a plurality of solenoid valves and a diaphragm unit including a diaphragm defining a pressure chamber, air pressure within the pressure chamber being adjusted by selective activation of the solenoid valves which communicate the pressure chamber with pressure sources of different pressure levels, in which a casing of the actuator defines an accommodating chamber for accommodating the solenoid valve unit and a wall surface of the chamber is provided with ribs for guiding and positioning the solenoid valve unit inside the chamber. The ribs may be adapted to make a sliding contact with a side surface of the yokes of the solenoid valves and a smooth surface a printed circuit board which is attached to the solenoid valve unit. Alternatively or additionally, the ribs may be adapted to be fitted into a gap between a pair of adjacent yokes of the solenoid valves.

Abstract: A valve having a piston which, by the admission of pressure, is displaceable is a bore of a valve housing for blocking and clearing lines leading through the valve housing, wherein at least one piston (5) is displaceable in an outer piston (3), which inner piston (5) projects beyond the outer piston (3), with a valve seat (6, 7) in each case being allocated to both pistons for blocking and clearing a line.

Abstract: A pneumatic drive mechanism for use with positioning apparatus or the like, having a drive housing, a drive element such as diaphragm disk, piston or the like, movably seated therein and rigidly connected to a drive rod or similar device. The drive element is responsive to compressed air on one side thereof and to forces from at least one spring operating in opposed action to the compressed air. The spring is arranged within the drive housing. The drive mechanism also has a signal processing device such as a position controller, position encoder, limit signal generator, solenoid valve or i/p converter or similar devices. The signal processing device or devices are integrated within the drive housing in an accomodation space which is free of the spring or springs, of the drive rod and of the drive element.

Abstract: A fluid-pressure-operated, three position working cylinder includes a cylindrical housing having a graduated bore formed therein and a movable primary piston dividing the bore into first and second pressure chambers. A movable secondary piston surrounds a portion of the primary piston and moves relative to the primary piston within the limits of a piston stop arrangement formed on opposing surfaces of the pistons. The piston stop arrangement includes an elastic stop on the primary piston which interacts with a sloped stop formed on the secondary piston so that upon initial insertion of the secondary piston onto the primary piston, the sloped stop compresses the elastic stop. The sloped stop includes a lip portion that can contact the elastic stop so as to restrain the secondary piston from further movement in one direction relative to the primary piston. A vent passage formed in the housing allows venting of the space between the two pistons.

Abstract: A speed control actuator includes a diaphragm forming a movable wall of a variable pressure chamber. An output member is fixed to the diaphragm to impart diaphragm movement to a throttle valve of the automotive vehicle. Three solenoid valves are mounted on a common bracket and are disposed in the variable pressure chamber for controlling vacuum and atmospheric pressure into the chamber. Two of the three solenoid valves are normally biased open to assure disengagement of the actuator.

Abstract: Disclosed is an air filter unit for a pressure actuator such as a vacuum actuator for a speed control of an automobile comprising a solenoid valve unit including a plurality of solenoid valves and a diaphragm unit including a diaphragm defining a pressure chamber, air pressure within the pressure chamber being adjusted by selective activation of the solenoid valves which communicate the pressure chamber with pressure sources of different pressure levels. A filter element holder defining a pair of receptacles for receiving filter elements therein is attached to the solenoid valve unit so as to intercept air flow from an external air source into the vacuum chamber by way of the solenoid valves. The filter element for a vent valve which is frequently used is finer in structure than that for a safety valve which is less frequently used and is required to be capable of rapid introduction of air into the vacuum chamber.

Abstract: A hydraulic control system comprising a hydraulic actuator having opposed openings adapted to alternately function as inlets and outlets for moving the element of the actuator in opposite directions and a variable displacement pump with loading sensing control for supplying fluid to said actuator. A pilot operated spool type meter-in valve is provided to which the fluid from the pump is supplied and a pilot controller alternately supplies fluid at pilot pressure to the meter-in valve for controlling the direction and displacement of movement of the meter-in valve and the direction and velocity of the actuator. A pair of lines extends from the meter-in valve to the respective openings of the actuator and a pilot operated meter-out valve is associated with each line of the actuator for controlling the flow out of the actuator when that line to the actuator does not have pressure fluid from the pump applied thereto.

Abstract: A pilot operated directional control valve having a diaphragm held between a passage block which has a feeding port, at least one loading port and at least one discharge port, and an opposed control block which has pilot pressure passages. The ports of the passage block open into the end face of the passage block adjacent to the control block through respective fluid passages. The pilot pressure is exerted on the diaphragm by the pilot pressure passages to control the fluid connection between the ports of the passage block. The fluid passages are located in a concentric arrangement. The diaphragm has a center valve portion with an annular valve portion therearound. The two valve portions can be independently controlled by the pilot pressure acting thereon to control the fluid connection between the two adjacent fluid passages.

Abstract: Automatic device for economizing compressed air comprises a means for ensuring the passage of driving fluid under pressure during most of the stroke of the moving element of a user apparatus. The device consists of a single-unit body having a first circuit connecting a fluid supply pipe to one chamber of the cylinder actuator. The first circuit is controlled by a valve moving with a piston subjected to the action of an elastic means and slidably mounted in the body. The piston is actuated by the presence or absence of a pressure signal, the body having a second circuit by-passing the first circuit and connecting a fluid exhaust pipe to the cylinder chamber.

Abstract: A contractility actuator includes a longitudinal quadrilateral mesh of relatively inelastic segments with anchor points at either end, an expandable bladder confined within the mesh and means for introducing and inflating the bladder with a liquid for generating a contractile force between the anchor points mechanically analogous to a muscle but of much greater magnitude. Two or more of the contractile actuators are arranged in a system for precisely articulating one or more arms pivotally secured at the distal ends of a structural member.

Abstract: A pressure controller for an air spring having a gas-filled, variable interior space for spring action between relatively-vibrating bodies has interconnected intake and outlet valve stems for opposite valve action and an actuating piston responsive to the gas pressure in the variable interior space and an oppositely-acting compression spring for moving the valve stems. High pressure in the variable interior space opens the outlet valve to vent the variable interior space to the atmosphere and low pressure in the variable interior space opens the inlet valve to supply compressed gas to the variable interior space from a reservoir.

Abstract: An actuation installation for use under extreme environmental conditions, such as freezing, uses a two-fluid system in which one fluid is impervious to the extreme environment, and the other fluid, such as water, is not. A two-chamber accumulator-separator has a water chamber connected to a water source via control valves and a working fluid chamber connected to a hydraulic actuator port. The other actuator port is connected to a working fluid chamber of a two-chamber accumulator having a sealed air-pressure chamber. When water is admitted to the water chamber, the actuator will move in a first direction further compressing the air in the air pressure chamber. When the water is drained from the water chamber, the accumulator air-pressure moves the actuator in the opposite direction. The actuator is positioned in the extreme environment, with the remainder of the system installed in a protected environment such as underground.

Abstract: The invention relates to a coaxial multi-function insertable hydraulic distribution cartridge valve including various inlet and outlet ports (P1,X1,R1,S1,s1,D1,B1), a first compensating slide (N1) urged towards a position of full opening by a first spring (r1), a second internal slide (J1), concentric with the first, providing the principal regulation of the oil inlet flow rate, urged by a second spring (r2), against the control pressure delivered by the inlet port (X1), towards the position of closure of the communication between the oil pressure inlet port (P1) and the outlet port (R1) delivering the actuating pressure, and isolating (C) check valve and a backfeed (G) check valve, which are urged by a third spring (r3) to return these two check valves into the position of closure of communication towards (S1) for the check valve (C) and towards (T1) for the check valve (G), a third balancing slide (E1) urged by a fourth spring (r4), against the pressure delivered by the balancing pressure port (B1) and the

Abstract: A fluid control valve apparatus comprises logic valve means including a valve housing, a first valve member defined in the valve housing, and an axially movable valve body arranged in the first valve chamber, with the valve body including opposite end portions and a conical surface portion brought into contact with the conical surface portion when the valve body is moved in a valve closing direction. First and second hydraulic fluid chambers are defined in the valve housing and communicate with each other when the conical surface portion is out of contact with the valve seat and out of communication when the conical surface portion contacts the valve seat. A first pilot chamber in the valve housing, adjacent one end portion of the valve body, biases the valve body in a closing direction by a first pilot pressure signal.

Abstract: A hydraulic control system for an elevator or other similar reciprocating user is disclosed, which comprises an adjustable throttle valve and a control or bypass valve disposed in the fluid supply line between the pump and elevator. A pressure difference balance is provided for controlling the operation of the control valve, and the pressure difference balance has one end operatively connected to the pressure provided by the pump, and the other end operatively connected to the pressure in the user or load line. The control valve is thus adapted to maintain a desired pressure difference across the throttle valve which is independent of the load on the user. In addition, the zero setting of the pressure difference balance is adjustable, so as to permit the system to be equally operable in both the upward and downward movements of the elevator.

Abstract: A valve arrangement for a compressed-air operated nailing apparatus with valve pistons operating without intersection in such a manner that the one valve piston cooperates with the working cylinder and is guided by the other working piston which is controlled by an auxiliary control valve, wherein the first auxiliary piston is also controlled at the same time, and wherein upon opening the valve arrangement the second valve piston is moved first into the opening position and the first valve pistion thereafter.

Abstract: A control system (10) for supplying an operational chamber (38) in an air motor with pressurized fluid causing rotors (18 and 20) therein to move and develop an output torque in response to an input signal. Electrically operated valves (52 and 54) selectively controlling the flow of fluid from first and second bellows means (48 and 50) which are normally seated to seal distribution conduit (34 and 36) connecting the operational chamber (38) to the atmosphere. A select high disc valve (104) in the fluid pressure supply passage provides operating fluid to the distribution conduit (34 or 36) opposite the one which is vented to the atmosphere. In a two position air motor powered actuator, the electrical signals for the valves (52 and 54) may be derived as a simple function of actual rotor rotation and rotor rotational speed.

Abstract: The invention relates to a driving unit for a feed pump, particularly for a crude oil feed pump which is suitable for recovery of energy. The delivery flow of a hydraulic variable displacement pump, in particular a pump of the axial piston type is used to perform the upstroke of the pump piston. A directional valve control means is provided to deliver the liquid volume displaced under pressure in the downstroke of the pump piston through the pump in the same direction of flow as for the upstroke. The pressurized fluid may either pass to a reservoir, wherein the pump drives a motor for supplying electrical energy back to the electric supply, or, respectively, may load a hydraulic accumulator which is connected to the suction port of the pump for performing the upstroke of the pump piston for which the accumulator is discharged, wherein the remaining torque only has to be supplied by the drive motor.

Abstract: A hydraulic control apparatus has at least two meter-in and two meter-out poppet valves. In order to be compact and deal with a great flow rate, the apparatus is arranged such that a pair of meter-in poppet valves and load check valves are located in an upper horizontal plane, a pair of meter-out poppet valves and solenoid-actuated pilot valves are located in a lower horizontal plane, and a pair of a pilot valve associated with the meter-out poppet valve and a reducing valve associated with the meter-in poppet valve are located in a middle horizontal plane and are respectively disposed in opposed relationship to each other, and the load check valve is vertically located in parallel relationship with the meter-out poppet valve.

Abstract: A pressure controller for an air spring having a gas-filled, variable interior space for spring action between relatively-vibrating bodies has intake and outlet valve stems for opposite valve action and an first actuating piston responsive to the gas pressure in the variable interior space for moving at least one of the valve stems. High pressure in the variable interior space opens the outlet valve to vent the variable interior space to the atmosphere and low pressure in the variable interior space opens the inlet valve to supply compressed gas to the variable interior space from a reservoir.

Abstract: An electro-hydraulic height corrector for motor vehicles comprising a hydraulic distributor having ducts connected, one to a pressurized supply source, another to suspension cylinders and another to an exhaust circuit, and means for connecting these different ducts together, and means sensitive to the position of the suspended part of the vehicle with respect to the none suspended part thereof.

Abstract: Electrohydraulic regulating device, particularly for aircraft controls, iuding a regulating cylinder having a regulating piston therein capable of being loaded at either end thereof for the positioning of which necessary volumes of operating fluid can be supplied separately to either end space of the cylinder by means of magnetically-operable valves; a computer by which switch pulses of variable duration to be fed to the magnetically-operable valves are determined in dependence on the specified adjustment distance of the regulating piston; restrictors which determine the throughput of operating fluid through the magnetically-operable valves and sensors which after the switching of a respective magnetically-operable valve generate electrical signals which are fed back to the computer purely as a confirmation of operation. The restrictors are so arranged in an operating fluid circuit that, on movement of the piston, operating fluid flows through only one of the restrictors.