Abstract: A regeneration valve includes a housing defining a first port, a second port, a third port, and a chamber fluidly communicating with the first, second, and third ports. The chamber has a valve element movable between a first position, in which the second port fluidly communicates with the first port, and a second position, in which the second port fluidly communicates with the third port. A resilient member biases the valve element towards the first position. In operation, a flow restrictor element moves between the first port and the second port for restricting fluid flow from the second port to the first port. At a predetermined flow rate between the second port and the first port, if a supply pressure of fluid at the actuation chamber exceeds the bias of the resilient member, the valve element moves to the second position for fluidly communicating the second and third ports.

Abstract: A valve of a piston pump for a vehicle brake system having a closing body which is resiliently preloaded against a sealing seat. The closing body is formed in two parts with a damping piston and a closing element inserted therein. The damping piston is axially displaceably guided in a cylindrical piston guide. At least one flow channel is provided between the damping piston and the piston guide. The at least one flow channel is configured such that fluid can flow around the damping piston in the longitudinal direction thereof through the at least one flow channel.

Abstract: Valves are associated and integrated inside a body C. A steering valve includes two cylinders A and B, concentric with the steering shaft D. The cylinder A rolls conjointly with the shaft. The valve controls the direction of the fluid circulation in the cylinders which effect the steering. The safety valve includes two pistons P1, P2 and a spring S, and makes the control easier of the steering, in an occasional lack of fluid pressure (pump damage, fluid leak, cut of the shaft strap, engine stop). A progression valve includes a cylinder and the piston PV. It operates by means of the vacuum effect TV, produced in the engine air admission of the vehicle, controlling the return of the piston P1 in a progressive way, from a certain speed of the said vehicle.

Abstract: An arrangement for hydraulic actuation of a movable component on vehicles, particularly a vehicle top, trunk lid, a cover or the like, includes at least one double-action working cylinder (1) whose working chambers are connected to a pressure source (5) via a pressure line (4) or whose working chambers are at least temporarily connectable thereto through a switching valve (11).

Abstract: This power steering cylinder assembly consists of a hydraulic cylinder which is closed at each end. A piston rod travels through the center of each end has a piston assembly fastened on it. The cylinder has holes in each end for fluid to enter and move the piston or be discharged from the cylinder. The piston has holes completely through it and a flat ring valve is supported on each side and slides in the piston. These valves are urged away from the piston by spring pressure. When power steering is used these valves close by the fluid pressure to seal the piston. When the fluid pressure drops low enough so manual steering must be used the valves open and the fluid travels through the piston as it is pushed back and forth.

Abstract: A power steering cylinder assembly including a cylinder divided by a piston into opposite chambers and a valve controlling flow between a pump, a tank and the chambers. Bypass passages selectively connects the opposite chambers when there is no flow from the pump. The bypass passages includes first and second sets of axial passageways in the wall of the cylinder. Each passageway of the first set of axial passageways having an inlet in the first operating chamber and a first outlet in the exterior of the cylinder. Each passageway of the second set of axial passageways having an inlet in the second operating chamber and a second outlet in the exterior surface of the cylinder. The first and second outlets being in two respective circumferential lines on the exterior surface of the cylinder.

Abstract: The invention relates to a low-vulnerability device for the operation of a lifting and propulsing helicopter rotor by means of a cyclic plate mechanism, in which the non-rotating plate (5) is coupled at four points (1, 2, 3, 4) to four hydraulic actioning servocontrols each comprising a power jack (9), an anchoring system (10) and a servocontrol-distributor (41, 42), three servocontrols being used when normally working, the fourth being used in back-up in the event of a failure of one of the other three. Each power jack (9) is supplied by an independent hydraulic circuit which comprises the servocontrol-distributor (41, 42) operated by a mechanical input, connected to the cockpit by linkage (13), and a disengageable anchoring system.

Abstract: A power steering trim control system for use with steering mechanisms provided in automotive vehicles. The trim system includes a flow distribution valve (38) which selectively directs fluid pressure to segregated groups (34, 36) of valve lands (32) of a rotary valve (24) in proportion to the deflection of a torsion bar (22). The valve lands (32) are angularly off-set from those found in the prior art in order to produce a desired biasing, or torque compensation. The torque which is manually transmitted is progressively supplemented by fluid pressure delivered to the pressure movable part (14) of a steering linkage (16). The invention also includes a process control circuit (60) which is provided with a vehicle speed sensor (60) for generating an electrical signal representative of vehicle speed.

Abstract: A four way directional control valve comprises a valve body having a sleeve formed therein, a spool slidable in the sleeve, two output ports, a pump port and two tank ports formed in the valve body so that the output ports can be a pressure side and an exhaust side by operation of the spool. The four way directional valve further comprises a communicating passage formed in the valve body to provide communication of the output ports with each other, a fixed orifice disposed in the communicating passage, a control passage, formed in parallel with the communicating passage, a control spool disposed in the control passage movable in response to a differential pressure between the output ports to block the communicating passage.

Abstract: A four way directional control valve comprises a valve body having a sleeve formed therein, a spool slidable in the sleeve, two output ports, two pump ports and a tank port formed in the valve body so that the output ports can be a pressure side and an exhaust side by operation of the spool. The four way directional valve further comprises a communicating passage formed in the valve body to provide communication of the output ports with each other, a fixed orifice disposed in the communicating passage, a control passage, formed in parallel with the communicating passage, a control spool disposed in the control passage movable in response to a differential pressure between the output ports to block the communicating passage.

Abstract: A device for the hydraulic boosting of steering force comprises a cylinder having a working piston which is coupled with a steering rod assembly. The cylinder includes working chambers into which hydraulic pressure can be introduced by way of multi-directional control valves. The steering aid is designed as an accessory unit for a brake system with an auxiliary hydraulic energy supply and will be put into function only during vehicle standstill or at low vehicle speeds.

Abstract: Check device for a redundant flight control apparatus comprising at least two servo drive devices. Failure in supplying fluid and wedging of a control valve (20) can be simulated. Failure of the bypass valve (35) can be checked by reading and comparing the volume flows of the respective pumps as well as by evaluating the travelling rate of the servo drives (1, 2) by the pilot.

Abstract: An electrohydraulic servovalve which includes as an integral part thereof a monitor valve which senses the absence or lack of system pressure in the first or second stages of the valve and translates in the absence thereof to deactivate load control. The torque motor of the electrohydraulic servovalve is biased, electrically or magnetically, to provide a failure indication in the first stage of the valve in the absence of or excess of applied electrical signals to the torque motor.

Abstract: A power servo booster in which the diaphragms are freely pivotable from the power piston so as to prevent folding and collapse of the diaphragms in the non-powered state. A shell of the booster is divided into two volumes with a power piston and diaphragm in each volume dividing the corresponding volume into chambers at a negative pressure and at atmospheric pressure. The inner peripheral ends of the two diaphragms are fitted into grooves formed on the sides of the pistons in such a manner as to be freely rotatable or pivotable thereby preventing folding of the diaphragms.

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 pair of meter-in valves are provided to which the fluid from the pump is supplied and a pilot controller alternately supplies fluid at pilot pressure to a meter-in valve for controlling the displacement of movement of the meter-in valve and the direction and velocity of the actuator. Alternately pilot pressure from the pilot controller is applied simultaneously to both of the meter-in valves in conjunction with the venting of one of two load drop check valves to provide a regenerative mode.

Abstract: Fluid introduced into an actuator moves the piston, against the force of a return spring, to extend the actuator. After the actuator has extended a sufficient amount to perform its intended function, the piston contacts and moves a sleeve type closure for an outlet port. The additional extension of the actuator moves the sleeve to open the outlet port. This allows fluid from the source to flow through the actuator and out through the outlet port to an expansible chamber in a second actuator. In a preferred system, the second actuator is also a single acting linear motor and it includes a return spring. At the conclusion of the function of both actuators, a bypass valve in a return line is opened to allow fluid to flow out from the expansible chambers of both actuators back to a reservoir. The fluid from the second actuator flows back to the outlet port of the first actuator and from such port through a passageway which connects such port with the inlet-outlet port of the first actuator.

Abstract: An electrically driven oil pressured power steering apparatus is disclosed herein. The apparatus comprises an oil pump driven by an electric motor for supplying a working oil to a power cylinder, a control valve for controlling the supply of the working oil and a manipulating apparatus and an electronically operated on-off means which, in common, control a power supply to the electric motor. In the apparatus, a state of power steering is shifted to a state of manual steering in accordance with a stop of the electric motor effected by the electronically operated on-off means.

Abstract: Fluid in the relatively long lines (22, 24) between a control valve (16) and a fluid actuator (14) can become overly viscous in cold weather. Herein, fluid is circulated through such lines (22, 24), at least during cold weather, even when the fluid actuator (14) is not being used. This flowing is discontinued in response to shifting of the control valve (16) to a position where it motivates the actuator (14) and in response to pressure in the circulating path (20) exceeding a selected level.

Abstract: A fluid control system for controlling a fluid motor (12) wherein a pressure regulating pilot valve (10) controls a directional control valve (11) by manipulation of handle (21) associated with the pilot valve (10). The directional control valve (11) includes a make-up valve (84). The pilot valve (10) includes a spool (26) having a recess (98) providing selective communication between the backside of the movable valve member (86) of the make-up valve and an exhaust recess (100) communicating with the reservoir tank (36). A direct mechanical connection is provided from the handle (21) to the spool (26) as the result of an abutment of an upper end portion (102) of the spool (26) with a surface (49) on the plunger (28) engaged by the control handle in effecting the positive movement of the spool (26) to effect the desired communication between the recess (98) and recess (100). The spool normally is resiliently movable to effect a desired pressure regulation fluid flow through the pilot valve (10).

Abstract: The safety system employs a shut-off valve, a control valve and a selector. The selector is formed of two non-return valves which are connected to the two chambers of the servomotor and has an output connected to one chamber of the control valve. Another chamber of the control valve is connected to the low pressure chamber of the servomotor while the intermediate chamber is connected to the shut-off valve in order to influence the movements of the piston of the shut-off valve. A solenoid actuates the control valve to deliver either high pressure fluid from the high pressure servomotor chamber or low pressure fluid from the low pressure servomotor chamber to the shut-off valve.

Abstract: A hydraulic system (9) includes a hydraulic motor (10), a main control valve (17) for controlling said motor (10), a make-up valve (78,79) operatively associated with said main control valve (17) and a vent line (93,94,95,99) for selectively venting said make-up valve (78,79). In such hydraulic systems, and in particular, in prior art hydraulic systems used to raise and lower a load, there is always the possibility that should hydraulic pressure not be maintained in the vent line the make-up valve could come open and the load could unexpectedly move. Such a situation could occur with, for example, air trapped in said vent line and the simultaneous failure of a pump of the system. The present invention solves this problem by providing pressure maintaining arrangement (200) in fluid communication with said vent line (93,94,95,99).

Abstract: In combination with a double-acting cylinder having pressure and exhaust ports, a cylinder control valve having a spool having a pair of control positions with pressure, cylinder and exhaust ports, and conduits between the valve cylinder ports and cylinder ports, and a source of compressed air connected to the valve pressure port, a safety control system which comprises a pilot-operated valve housing having a pressure port connected to the source of compressed air, a pilot port and a pair of cylinder ports connected to the cylinder conduits. A valve spool within said housing has first and second control positions with an operative device on the housing which normally biases the safety valve spool to a first control position pressurizing opposite ends of the cylinder and with the pilot port connected to the source of compressed air. A build up of pressure to the pilot port moves the safety valve spool to its second control position, blocking communication between the safety valve and the cylinder ports.

Abstract: The hydraulic brake booster power piston has a rectangular cross section seal groove containing a rectangular cross section lathe cut seal having a greater inner diameter than the groove as well as a greater outer diameter. Radial clearance is provided between the piston and the cylinder wall. The groove has one or more holes at its inner diameter opening axially into the booster power pressure chamber. The seal is also axially thinner than the groove. Power pressure holds the seal in sealing relation with the cylinder wall and the piston. When fluid must flow from the exhaust chamber side of the piston to the power chamber side (e.g. during manual no-power operation) the seal moves to the other groove side, allowing flow radially inward in the groove and past the seal inner periphery through the hole or holes to the power chamber.

Abstract: A hydraulic control system has two fluid supply circuits which control fluid pressure supplied to respective chambers of a fluid-controlled actuator, each chamber having an individual piston mounted on a common actuator rod. In normal operation, a major part of the pressure is supplied to the actuator by the first circuit in accordance with control signals derived from an external source. The second circuit supplies pressure to its respective chamber at a lower level in accordance with control signals derived from the differential pressure across the piston in that chamber, the pressure supplied by the second circuit acting to reduce the differential pressure across the piston. The system also includes a control unit that responds to malfunction of the first circuit or error in the control signals supplied to the first circuit, by disconnecting the first control circuit from control of the actuator, such as by equalizing pressure across the piston in the first chamber.

Abstract: A control valve adapted for use in working machines for hydraulically controlling the lifting movements of the working machine such as a rotary blade or plow connected to a power machine, said control valve comprising essentially a change-over valve for connecting or shutting off a cylinder port to or from a pump port or tank port by a spool operation, and a compensator for guiding cylinder port pressure into an oil chamber of a plunger on the spring loaded side for bypassing the pump discharge oil opposedly to the pump pressure, and characterized by provision of a passage for connecting the oil chamber of the compensator on said spring loaded side into the tank port or cylinder port through said change-over valve, whereby when said change-over valve is at its neutral or dropping position, said oil chamber is communicated with the tank port, and when said valve is at its elevating position, said oil chamber is communicated with the cylinder port.

Abstract: In an injection molding machine of the type comprising an injection cylinder, a feedback circuit for feeding back the oil in the rear chamber of the injection cylinder into the front chamber thereof and a booster cylinder, a pressure oil accumulator is connected to the booster cylinder through a valve for supplying pressurized oil for actuating the booster cylinder. A check valve is connected in parallel with the valve. When water hammer occurs at the end of the injection stroke the check valve opens to absorb the energy of water hammer by the accumulator.

Abstract: An installation for the servo-assist of actuating devices in motor vehicles, especially of a hydraulic brake system, in which a control member, such as the brake pedal, acts on an actuating device, such as a master cylinder of a two-circuit brake system by way of a servo-member; a hydraulically actuatable servo-unit is thereby arranged between the control member and the actuating device whose first part is supported at the control member and whose second part is connected with the actuating device; the actuation of the servo-unit is controllable from a hydraulic pressure medium source in the manner of a follower control by means of a control device connected with the control member.

Abstract: A hydraulic control assembly especially suited for operation of a fail-safe valve. An integral structure is provided having a pair of check valves disposed in passageways extending from one chamber of a piston operator to a hydraulic reservoir and the other chamber of the piston reservoir, and in a fluid line extending from a high pressure source. In a fail-safe valve, cavity pressure normally acts on the valve stem and provides the force which moves the valve to its close position. A spring is disposed in the second chamber of the piston operator and, in conjunction with any force resulting from internal cavity pressure on the valve stem, aids in closing the valve. The second chamber is equal or greater in volume than the first chamber so that all of the hydraulic fluid displaced from the first chamber during valve closing can flow into the second chamber. In this way, the hydraulic power needed to pump hydraulic fluid back to the reservoir is not effected by installed hydraulic system variations.

Abstract: A fluid pressure actuated drive for providing for the closing unit of an injection moulding machine a to and fro traversing motion of a movable part of the unit with little force and a clamping of the closed unit with a greater force. The device has at least two double acting piston and cylinder devices which act in parallel and the pistons of which each have at each side a piston rod which passes through a seal in the responsive adjacent cylinder end. The piston rod on one side of at least one piston is thicker than that on its other side and the piston rod on one side, which corresponds to the same working side as one side of the one piston, of the or each other piston is thinner than that on its other side. Traverse in one direction is provided by applying fluid pressure to both sides of the one piston, and in the other direction by providing fluid pressure to both sides of the other piston. Clamping pressure is provided by applying fluid pressure to one side only of each of the pistons.

Abstract: A construction vehicle, such as a motor grader, comprises a work tool mounted thereon and adapted to be selectively moved by at least one double-acting hydraulic cylinder. A fluid circuit comprises a pressurized fluid source adapted to communicate fluid to the cylinder via a first control valve. A normally closed second control valve is operatively connected between a storage tank of the fluid source and the rod and head ends of the cylinder for exhausting fluid therefrom to the tank directly upon actuation of an independent actuation means. Opening of the second control valve will thus place the cylinder in a "float" condition of operation.

Abstract: A pneumatic actuator having a double-acting piston separating two pressure chambers, spring means to urge the piston in one direction; and valve means adapted to admit compressed air to one of the chambers and thus to load the spring means, then to transfer some of said air into the other of the chambers at a selected phase-position of said piston, and then to open the one chamber to atmosphere so that the combined forces of the spring means and of the compressed air acting on the piston in said other chamber complete the power stroke of the actuator.

Abstract: A load supporting hydraulic system having a pilot operated main control valve is provided with pilot controlled load check valve operative to permit free flow of fluid from said control valve toward the load supporting means of the system in response to pilot pressure and to block fluid flow from the load supporting means toward the control valve. The system includes valve means operative independent of the main control valve to permit the load check valve to be opened by fluid pressure in the load supporting means to allow fluid flow therefrom to the reservoir. The system further includes safety valve means for blocking fluid flow to pilot control means.

Abstract: The steering wheel controlled valve operator in a fluid power steering system, is mechanically held in a neutral position by centering springs associated with fluid pressure controlled reaction pistons yieldably resisting movement of the control valve by the valve operator. Check valves opened in response to suction pressure, conduct fluid in by-pass relation to the control valve between a servo motor chamber and a return fluid line, the control valve connecting both servo motor chambers to the return line in the neutral position.

Abstract: In an earthmoving scraper a low volume, low pressure, pilot pump supplies fluid pressure to a pilot control valve which routes this fluid through bleed lines to a remote scraper control valve that operates the bowl jacks on the scraper from a separate source of pressurized hydraulic fluid. By manually varying the bleed rates of the output of the pilot pump with the spool of the pilot valve, proportion actuation of the control valve can be obtained through differential pressures in the bleed lines connecting it to the pilot valve. A safety valve connected in the bowl carry circuit supplies an alternate source of fluid pressure to the pilot valve if the pilot pump fails, ensuring positive fail-safe operation of the system.