Abstract: Method and apparatus for isolating hydraulic devices in a stacked hydraulic circuit of modular design employing an isolator valve module which enables partial and/or complete isolation of components in a hydraulic system to be isolated for inspection, testing, maintenance or replacement, by selective operation of the isolator valves in the isolator valve module. The isolator valve module may be a sub-plate module supporting other modules or a plurality of stacks of modules or may be a “sandwich” type module sandwiched between a sub-plate and another module or between two sandwich-type modules.

Abstract: A multi-channel valve having a valve seat, a valve seal, and valve seal housing. The assembly of the apparatus creates a plurality of inlet, exit, and cross channels enclosed by elastomeric portions of a valve seal. The elastomeric portions of the valve seal create bounded distensible chambers. Pressure exerted by a fluid in excess of the cracking pressure of the seal tends to distend portions of the elastomeric seal and allow flow through and into the chambers. When inflow pressure falls, the elastic rebound of the elastomeric portions of the seal tends to expel fluid from the valve without backflow. Cross channel capacity allows mixing of the fluids. The plurality of, and differentials between, chambers allows one fluid to completely purge the valve of other fluids. The valve may be configured with additional backflow prevention capacities, such as channel variations, secondary elastomeric members, and variations in primary membrane properties.

Abstract: A multiport valve having a valve body and a controllable opening in a surface is provided. An activation element is also disclosed which is controllably attached to a sealing element in communication with the surface. An elastomer membrane is provided about the activation element and in contact with the sealing element. The activation element selectively elevates the sealing element from a valve seat. Additional multiport valve embodiments are also disclosed including a toggle to regulate multiple valve seats.

Abstract: A directional control valve includes a pressure regulator piston configured as a hollow slide with a radial passage positioned in such a way that a connection from the internal chamber of the pressure regulator piston to a pump pressure annular channel (P) can be regulated by the radial passage and a second radial passage of a directional control valve piston. The second radial passage constitutes a control edge, which is used to regulate the connection from the internal chamber to a load sensing annular channel (LS). An annular groove, which in the neutral position forms a connection from the internal chamber to the load sensing annular channel (LS), is joined to the second radial passage. The pressure regulator is impervious to different flow forces caused by different mass fluxes and ensures that the hydraulic consumer is prevented from moving in the neutral position.

Abstract: An electro-hydraulic valve is provided for use in a system to control flow and/or pressure within the system. An electro-hydraulic valve arrangement includes a housing and a valving mechanism disposed in the housing. The electro-hydraulic valve arrangement has a hold coil assembly connected to the housing adjacent to the valving mechanism. A force control member having a clapper face is positioned adjacent to the hold coil assembly and the clapper face thereof is maintained at a predetermined distance from a coil face of the hold coil assembly. A double precision adjustment mechanism is operative associated with the force control member and is operative to precisely control the distance between the coil face and the clapper face.

Abstract: A braking system control requires that a first or service braking system be actuated before a second or parking braking system can be released to prevent unexpected movements. A sensor senses that the service brakes are engaged and controls a device to release the parking brakes. A latch ensures that the parking brakes remain released. For example, a piston and check valve form the sensor and latch. Service brake pressure works against the piston. Above a threshold level, service brake pressure drives the piston to open a valve that provides pressurized air to a parking brake release system. Once released, the check valve directs parking brake release pressure to the piston to keep the valve open.

Abstract: A switching device for a machine, especially a digger, has at least one supply connection and one useful connection in addition to at least one hydraulic accumulator. An on-off valve is arranged between the supply connection and the useful connection, and separates the supply connection at least partially from the useful connection in one of its switching positions, in addition to ensuring that the hydraulic accumulator is charged on the fluid side via the supply connection. In another switching position, the supply connection is connected to the useful connection. A substantial improvement relative to conventional switching devices is attained by being able to guarantee an emergency function before the machine is used to perform work.

Abstract: A spacer type pressure reducing valve for adjusting a fluid pressure is mounted between a solenoid valve, which switches a flowing direction of pressurized fluid, and a base, which supplies pressurized fluid to the solenoid valve. First and second pressure-reducing portions are integrally accommodated in a valve body of the spacer type pressure reducing valve. The spacer type pressure reducing valve is compact and is capable of adjusting pressure in two output ports.

Abstract: A reversing valve for a high pressure spring gun, comprising: a pump connection; a connecting duct; a first section of the connecting duct connected to the pump connection; a second section of the connecting duct leading to a high pressure discharge; a block valve, being a transition between the first and second sections, that can be isolated by switching off the high pressure gun; a throttle, linked with the first section of the connecting duct to let fluid through; an exhaust duct linked to the throttle and leading to a drain; and a discharge valve operated by an electric switch to isolate the exhaust duct when the high pressure spray gun is switched on.

Abstract: A hydraulic distributor that has a regulating balance including a housing hollowed in the distributor body and containing coaxially a fixed central core. A tubular plunger is interposed sliding freely, coaxially, between the core and the housing and co-operates with a lateral orifice connected to a working orifice. The core and the plunger define between them an annular chamber. The plunger has a first radial annular surface subjected to the highest charge pressure (LS) and a second annular surface subjected to the pressure of the intake fluid. A central passage in the core constitutes a first orifice emerging at one end of the housing exposed to the highest charge pressure (LS). A second orifice emerges in the annular chamber and a third orifice is located opposite the other end of the housing and remains closed by the plunger as long as the charge pressure of the distributor is below the highest charge pressure (LS).

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: A snap pilot used to pneumatically energize and de-energize a control device, such as a valve. The pilot has two valves—one to admit pilot pressure, and one to exhaust pressure. The pilot incorporates valves having an elastomeric seal but maintaining the precision of metal to metal contact. In the preferred embodiment, the elastomeric seal is an O-ring placed in a groove, without adhesive, having only a small amount of deflection when the seat is closed, whereby simultaneous metal-to-metal and elastomer-to-metal contact is achieved.

Abstract: The present invention relates to automatic transmissions of land motor vehicles. In particular the present invention refers to the field of automatic transmission torque converter clutch regulator valves. The present invention comprises of a first spool valve, a second spool valve that attaches to the first spool valve, a sleeve valve that attaches to the second spool valve and an end plug that is placed on the sleeve valve. The valve assembly controls the volume supplied to the apply circuit. The present invention limits both apply and release pressure circuit. The valves of the present invention fit into existing bores and control both circuits. The switch valve prevents main line drop during apply circuit regulation.

Abstract: A hydraulic pilot control system having two control outputs to which a control pressure can be applied and having a hydraulic pilot controller, which has a handle which can be pivoted from a neutral position in a first direction and in a second direction, and a pressure valve that can be displaced from the neutral position by the deflection of the handle. During pivoting of the handle in the first direction and during pivoting of the handle in the second direction, the pressure valve can be adjusted with the same effect, and wherein there is a directional control valve which, depending on the pivoting direction of the handle, connects a control output of the pressure valve to the first control output or to the second control output, whereby a behavior of the pilot control pressure which is symmetrical with respect to the deflection of the control lever in the two directions is adjustable in a simple way.

Abstract: A dual-spool hydraulic directional valve for controlling the motion of a hydraulic cylinder or similar device. The dual-spool hydraulic directional valve of the present invention is less costly to manufacture, may be more easily repaired, and is more resistant to contamination than current hydraulic directional valves. The dual-spool hydraulic directional valve of the present invention is particularly suited to applications where the valve is not required to hold a load. The valve of the present invention uses two valve spools, with each valve spool controlling flow of hydraulic fluid through a particular port or ports. The valve spools work independently from one another, therefore, the slight leakage of hydraulic fluid from one valve spool to the other will not markedly affect the operation of the valve. In a preferred embodiment of the valve, a lever is utilized to shift the positions of the respective valve spools, although other means, such as electronic solenoids may also be used.

Abstract: Stopcock actuator casing, comprising a base (1) having an underside and formed with a hole (2), the underside of the base being subdivided into at least three compartments (4,8,10), the first (4) of which surrounds the hole (2) and the second (8) and third (10) of which are each formed with two orifices (12,13,14,15) passing through the base (1).

Abstract: This invention concerns a gas assist mold dump valve positioned between a gas controller and a mold cavity. Preferably, the valve includes a pressure regulator having a body with a gas inlet and a gas outlet. A vent is formed in the body between the gas inlet and the gas outlet. The inlet is in fluid communication with the gas controller and the outlet is in fluid communication with the mold cavity. A piston is mounted for reciprocal motion within the body and is movable between a first position to close and a second position to open the vent. Finally, a check valve communicates with the inlet and the outlet and has an open position that allows gas to flow from the inlet to the outlet and a closed position to close off the flow of gas from the outlet to the inlet. In operation, gas entering the inlet urges the piston toward its first position, passes through the check valve into the outlet and then enters said mold cavity.

Abstract: The valves are associated and integrated inside a body C comprising:

Abstract: A control valve for operating a fluid-actuated device includes a fluid inlet, a fluid outlet and a passage in fluid communication between the fluid inlet and the fluid outlet, the passage defining a longitudinal axis. A valve seat is disposed in the passage and includes an upstream diameter and a downstream diameter, the downstream diameter smaller than the upstream diameter. A ball poppet is positionable in a seated line contact position with the valve seat. The valve seat has a valve seat angle relative to a centerline of the longitudinal axis that is greater than an angle formed by the centerline and a line tangent to the ball poppet at the seated line contact position.

Abstract: A valve system for the pre-engagement unit of a vehicle braking pressure modulator contains solenoid valves, which are controlled by an electronic braking system. Pneumatic pressure is fed into a brake cylinder on the vehicle wheels via a pressure regulating channel of the pre-engagement unit. The solenoid valves are configured as cartridge solenoid valves, so that assembly is simplified, and utilization of elastic tolerance compensating elements is unnecessary. A preferred embodiment includes three cylinder bodies connected end-to-end with no increase in cylinder diameter. This embodiment enables the use of identical armatures and identical magnet coils for different valve types, such as 3/2-way solenoid valves or 2/2-way solenoid valves. Also, these valves may be configured as normally open or normally closed, with identical outside dimensions. As such, three cartridge solenoid valves can be combined into a compact triple valve cartridge unit that further simplifies the assembly process.

Abstract: An improved hydraulic valve for a camera dolly includes a valve pin having an extension within a valve housing to reduce vibration and noise and to reduce hydraulic closing forces. The valve pin is resiliently supported by e.g., rubber o-rings at both ends. Valve performance is improved as reducing hydraulic forces on the valve pin results in smooth valve operation, especially when opening the valve under heavy loading.

Abstract: A fluid control system incorporates an orificing device between each of a plurality of pilot operated control valves in connection with a control device and a resolver. The pilot operated control valves are actuated by the control device to control different functions of a work machine. The actuation of the pilot operated control valves produces a pressure signal that is sent to the resolver. The orificing device includes a plurality of steps that may be varied in size and shape to dampen the pressure signal to the resolver so that independent control for the pilot operated control valves is achieved. Additionally, a precision edge is defined within the orificing device to control the flow of pressurized hydraulic fluid through the orificing device and maintain a consistent viscous drag therethrough independent of temperature and oil-viscosity variations.

Abstract: The present invention relates to a device for simulating static load of a connection to a ventilated rack of animal cages when at least one of the racks are not connected to a central ventilation system. Accordingly, the device assures that the ventilation system is balanced when one or more of the ventilated racks are removed from their respective air supply or exhaust drops of the central ventilation system. The device includes a pair of spring biased legs which automatically close when a rack is removed from the central air system. The legs have an outwardly curved shape at one end forming an opening between the first and second leg. In the closed position, ends of the legs are adjacent to one another such that the distance between the legs is reduced, thereby creating a partial obstruction to air flow in the connection which is identical to the static load created by the ventilated rack.

Abstract: A pneumatic sequential control valve for successive aeration and deaeration of two consumers, wherein for purposes of aeration compressed air is initially applied to the first consumer and only subsequently to the second consumer, and for deaeration the compressed air is initially let off from the second consumer and only subsequently from the first consumer, comprises a valve body with connections for a compressed air line and a first consumer and second consumer, wherein a cavity is provided in the valve body, bore holes extend from the connections for the consumers and for the compressed air line to this cavity.

Abstract: According to principles of this invention, an override controller is structured for being placed in pressurized fluid lines between a valve position transducer and a valve position actuator of an automatic position-controlled valve assembly, with the override controller receiving uncontrolled supply pressurized fluid and having an exhaust. The override controller receives pressurized fluid at first and second inlet ports from the valve position transducer and furnishes this pressurized fluid to the valve position actuator through first and second outlet ports for controlling the position of the valve during normal operation. However, valve mechanisms of the override controller can also be placed in positions for stopping flow of pressurized fluid through the first and second inlet ports and providing fluid flow from the uncontrolled pressurized fluid to the first and second outlet ports for controlling the position of an industrial valve during override operation.

Abstract: The invention concerns a hydraulic steering arrangement (1), having a steering valve (2), which connects a steering motor with a pump, and which has a slide (3) with two front sides (8), the slide being adjustable by means of a pressure fluid both through a hydraulic steering unit (4) with a steering hand wheel (5) and through an electro hydraulic steering unit (6) with a control pressure generator, the two steering units having working connections (7) and the front sides (8) of the slide (3) being connected with shuttle valves (9), each of which being connected with the hydraulic steering unit (4) on the one side and with the electro hydraulic steering unit (6) on the other side.

Abstract: A hydraulic directional control valve with a regulating balance comprising a plunger which can be displaced in a housing (13) under the action of a differential pressure (&Dgr;p) between the intake pressure (P) and the highest load pressure (LS), and which is designed to open, in proportion to this differential (&Dgr;p), a lateral orifice of the housing linked to a working orifice (A, B) of the directional control valve; the wall of the housing and/or the plunger is provided with a calibrated passage linking the intake of fluid at pressure (P) and the lateral orifice when the plunger is pushed back into an end position by the pressure (LS) exceeding the intake pressure (P); consequently, in spite of the excess value of the pressure (LS) intended to inhibit operation of the directional control valve, hydraulic fluid is delivered to the lateral orifice at a low rate and allows the hydraulic receiver controlled by the hydraulic directional control valve to be displaced at a low rate.

Abstract: A band controlled valve apparatus for controlling fluid flow from a source to a sink, including a base (12) having an upper surface and an aperture (16) extending from the upper surface through the base (12) allowing the flow of fluid from the source through the base (12) to the sink when the aperture (16) is not covered, an elongate flexible band (8) with a first portion (8a) in contact with the upper surface of the base (12) and a second portion (8b) extending forwardly of the first portion (8a) then upwardly and rearwardly above at least a part of the first portion (8a), the second portion (8b) being actuated to selectively move the second portion (8b) of the band (8) forwardly or rearwardly to cover or uncover, respectively, the aperture (16) with the first portion (8a) of the band (8) to thereby prevent or allow, respectively, fluid flow through the aperture (16).

Abstract: A valve arrangement using at least two piston slide valves flanged in series with their valve housings. The number of required line holes are reduced as are the number of sealing sites.

Abstract: In an electrohydraulic clamping module for a clamping element of a tooling machine comprising a pressure regulating valve in a flow line towards said clamping element is provided for regulating the clamping pressure. A pressure surveying sensor is integrated into said pressure regulating valve surveying said clamping pressure. Said pressure regulating valve is a leakage-free seat valve having a closure member which can be moved in relation to a stationary valve seat and can be adjusted by means of a control piston which is displaceable by the regulated pressure downstream of said valve seat and in closing direction of said closure member counter to a regulating force. Said pressure surveying sensor can be actuated by said control piston.

Abstract: A valve assembly for pressure adapted and volumetric flow adapted supply of at least one user may be supplied with hydraulic fluid or connected to a tank via two work ports of a continuously adjustable directional control valve. To the two work ports of the valve assembly a common pressure compensator is associated, the piston of which is guided in axial translation in an axial bore of the directional control valve spool, so that one of the two work ports may optionally be connected to the pump port upon suitable actuation of the directional control valve. At both end surfaces of the directional control valve spool and at the spring side of the pressure compensator piston, there acts a respective control pressure which, for example, corresponds to the highest system load pressure, the individual load pressure, or a pressure derived therefrom.

Abstract: A method and system for controlling the flow of a gaseous medium through a fluid are described. The method includes providing a rheologic fluid through which a gaseous medium can be conducted, and controlling the viscosity of the rheologic fluid to control the flow of the gaseous medium. The system has a rheologic fluid, which is located in particular in a device to be controlled, a guide guiding the gaseous medium through the fluid, and a field applier for applying a field at least partially in the area of the rheologic fluid.

Abstract: The present invention is directed to a hydraulic pressure control device which can overcome problems, such as a shock to an actuator or a pressure boost phenomenon involving a rapid increase in pump delivery pressure, conventionally encountered when a directional control valve is switched. The hydraulic pressure control device is constructed such that first and second connecting ports are connected to a tank when a directional control valve is in its neutral position, one of the first and second connecting ports is cut off from the tank and connected to an actuator and the other is cut off from the tank and closed when the directional control valve has been switched, in accordance with a position to which the directional control valve has been switched, and a maximum pilot pressure selectively taken from between a pressure compensating valve and a pair of check valves is introduced into a pilot line.

Abstract: The invention relates to a control valve for the control, independently of a load, of a hydraulic consumer with a distributing slide valve to control the direction of movement and the speed of movement of the consumer and a throttle valve associated with the distributing slide valve. The throttle valve, when there is a connection of a pump with the consumer, can be pressurized toward an open position by the pressure downstream of the throttle point of the distributing slide valve, and toward a closed position by the load pressure of the consumer and by a spring.

Abstract: Pressure compensating valves disposed at inlet sides of directional control valves are each configured with a step-shaped spool having a larger diameter portion and smaller diameter portions and pressure receiving chambers are provided to sandwich the larger diameter portion such that a pump delivery pressure and an inlet pressure of a metering throttle of the directional control valve acts in the chambers, respectively, and further pressure receiving chambers are provided at respective ends of the smaller diameter portions such that an outlet pressure of the metering throttle and a signal pressure act in the chambers, respectively. A check valve operated by the outlet pressure of the metering throttle is fitted in the smaller diameter end portion positioned on the side of the pressure receiving chamber to reduce the pump delivery pressure and produce a signal pressure.

Abstract: A valve device comprises a valve having an outlet passage (6, 7), a stationary surface, and a rotatable support member (15, 16) at a distance from the stationary surface, and a membrane (19) provided between the stationary surface and the support member. The membrane (19) is attached to the stationary surface and the support member in such a manner that when the rotatable support member is in a first rotating position in relation to the stationary surface the membrane covers an orifice (6, 7) associated with the outlet passage and located at the stationary surface and when the support member is in a second rotating position said opening is uncovered. The support member (15, 16) is provided rotatably about an axis (12) which in a plane, in which the axis (12) extend, forms an angle together with the generatrix of the stationary surface (10, 11).

Abstract: Pressure controlling valve mounted in such a manner as to be directly inserted between a change valve and a base and which has a valve body which is substantially equal to the change valve in width. In the valve body, there are provided a plurality of communication channels that communicate the corresponding ports of the change valve and base, a pressure control valve port that crosses those channels, a pressure control valve stem inserted in the port, and a controlling mechanism which are under a set pressure in cooperative action with the stem. The channels to guide pressure fluid for controlling pressure include a lead port inside the pressure controlling valve step and a lead clearance in the outer region of pressure controlling valve stem.

Abstract: A pressure-regulating valve, which is mounted in such a way as to be directly sandwiched between a transfer valve and a base has a valve body having substantially the same breadth as the transfer valve. The valve body contains a plurality of communication passages that allow opposed through-holes in the transfer valve and base; a pressure-regulating valve hole provided so as to traverse these communication passages; a pressure-regulating valve stem inserted into the valve hole; and means for cooperating with the pressure-regulating valve stem in regulating the air pressure in an output communication passage to a set value.

Abstract: A pair of directional control valves 8 and a pair of hold check valves 9 are disposed respectively between a pair of metering notches 6, which are formed in a land 4-1 of a spool 2 and have functions of both flow rate control and direction control, and a pair of actuator ports A, B. Each hold check valve comprises a valve body 90 in the form of a hollow spool having a seat portion 12 formed on an outer periphery and being subject to a pressure developed in an outlet passage 10 communicating with one of the actuator ports to act in the valve-closing direction. Each flow distribution valve comprises a valve body 80 being slidably fitted in the valve body 90 and having a front surface positioned to face an inlet passage 7 communicating with the metering notch and a rear surface positioned to face an control pressure chamber 30 communicating with a signal detecting hydraulic line.

Abstract: A pressure regulating valve usable in combination with a hydraulic steering system has a spring mechanism axially disposed between a pair of axially aligned valve spools. Movement of the spring mechanism in a first direction resiliently moves one of the valve spools to a position for communicating an inlet port with a control port and regulating the pressure in the the control port so that the pressure is proportional to the degree of movement of the spring mechanism. Conversely, movement of the spring mechanism in a second direction resiliently moves the other valve spool to a position for communicating the inlet port with another control port and regulating the pressure in the other control port so that the pressure is proportional to the degree of movement of the spring mechanism.

Abstract: A hydraulic valve apparatus is for controlling pressurized fluid flow to at least a pair of coupled hydraulic actuators in response to operator signals. The valve apparatus comprises a main body having main ports communicating selectively with a fluid supply and fluid return, body ports to communicate with the actuators, and a scavenge port to communicate with the return. Each actuator communicates with two control valves and one scavenge valve on the valve body to control fluid flow relative to the actuators. Control devices cooperate with the control and scavenge valves of each actuator so as to actuate the respective valves simultaneously. The control devices maintain the two related control valves in the same phase with respect to each other, but in an opposite phase to the respective scavenge valve.

Abstract: A direction control valve is formed by providing a main spool for establishing and blocking communication between an inlet port, first and second actuator ports and first and second tank ports. A pressure compensation valve comprising a check valve portion and pressure reduction portion is provided for compensating the pressurized fluid with a load pressure and supplying it to the inlet port. A plurality of valve blocks are connected to each other with respective first and second tank ports and respective pump ports in fluid communication. A pump port of one of the valve blocks is connected to a main inlet port, and a tank port of one of the valve blocks is connected to a main tank port. Thus, a hydraulic circuit for distributing a pressurized fluid from a single hydraulic pump to a plurality of actuators is provided.

Abstract: A universal hydraulic stop valve has housing having check valves in a check valve bore. A needle in needle bore has spaced apart seals which may alternately seal against valve seats on adjustable knobs, with movement of the needle, which may be mechanically linked to a machine element moved by a hydraulic actuator. The universal hydraulic valve sets accurate starting and stopping positions, and also provides for gradual feathered stops.

Abstract: A multiple hydraulic distributor device, having an antisaturation function wherein flow of hydraulic fluid is divided independently of load, which includes a hydraulic distributor device having a number of distributor devices assigned to controlling respective loads, which are stacked up face to face against each other as a stack and individually arranged in such a way that the stack has a common line passing through the stack for supplying working fluid under pressure originating from a source including a pump associated with a flow/pressure control device, a common return line for returning working fluid to a tank, and a common transmission line for transmitting control fluid at a pressure of highest load towards the control device for controlling the pump; a shut-off device arranged in the transmission line between a first group of distributors for which the transmission line is connected to the flow/pressure control device for controlling the source, and at least a second group of distributors for which t

Abstract: A directional control valve assembly having a pressure compensation valve in which there are provided a directional control valve in which a main spool is slidably inserted in a spool bore that is formed with a pump port, a first and a second load pressure detecting port, a first and a second actuator port, and a first and a second tank port; The pressure compensation valve that is connected with the pump port, includes: a pressure releasing zone which is adapted to the first and second load pressure detecting ports with the first and second tank ports when the spool lies its neutral position, and to block the first or second load pressure detecting port from the first or second tank port when the main spool lies at an intermediate site between the neutral position and a pressurized fluid supply position, and a passage having a counter flow preventing function for communicating the first or second actuator port and first and second load pressure detecting port with each other when the spool lies at an interme

Abstract: Fluid control valves are combined to form a layered multi-directional valve, each having a high-pressure port connected to a high-pressure source, a tank port opened to a low-pressure region, an actuator port, a spool capable of connecting said actuator port selectively either to the high-pressure port or to the tank port, and a load check valve capable of blocking the passage of a fluid through the high-pressure port. The load check valve includes a poppet which encloses a spring chamber and is forwardly biased by a spring contained inside the spring chamber. The poppet is movable between a backward position and a forward position inside a valve-containing chamber which has an opening on a portion of the outer wall of the control valve but this opening is blocked by a portion of the outer wall of another similarly structured control valve.

Abstract: A hydraulic pilot valve has a joystick which is normally maintained in a neutral position by coil springs acting on plungers which engage corresponding first cam surfaces of a cam fixed to the joystick. The plungers are each connected to respective valve members which are stroked to open the pilot valve when the plungers are depressed. When the joystick is pivoted to depress one of the plungers by engaging the head of the plunger so as to stroke one of the valve members, that valve member is held stroked by an magnetic detent. The joystick may then be released and the valve member will remain in its stroked position. When the joystick is moved back towards a neutral position, a second cam surface on the joystick engages an outer end portion of the depressed plunger and applies an axial force to the plunger. This disengages an armature component of the magnetic detent from an electromagnetic component.

Abstract: A pressure compensation valve has a check valve portion with a check valve bore with an inlet port and an outlet port in a valve body, a valve in the check valve bore for establishing and blocking communication between the inlet port and the outlet port, a pressure reduction valve portion constructed by forming a pressure reducing valve bore having a first port, a second port and a third port and being coaxial with the check valve bore in the valve body, a spring-biased spool in the pressure reduction valve bore to define a first pressure chamber communicating with the first port and a second pressure chamber communicating with the third port at both sides, making the second port communicate with the third port by a pressure of the first pressure chamber, and blocking communication between the second port and the third port by the pressure in the second pressure chamber.

Abstract: A pressure compensation valve comprises a check valve portion having an inlet port that is connected to a discharge path of a hydraulic pump, an outlet port that is connected to an inlet side of a directional control valve, and a valve for controlling an area of opening between both ports. A pressure reduction valve portion has a spool that defines at its both sides a first pressure chamber and a second pressure chamber, respectively, and is adapted to be slidable to allow the valve to be thrusted in a first direction in which the area of opening is increased under a self-load pressure applied to the first pressure chamber and to be slidable to allow the valve to be thrusted in a second direction in which the area of opening is decreased under a pressure within the second pressure chamber.

Abstract: A direction control valve is constructed in such a manner that a spool bore having an inlet port, an actuator port and a tank port is formed in a valve block, a spool slidable between positions for establishing and blocking communication of the input port, the actuator port and the tank port, is disposed within the spool bore, the input port and the tank port open to a first mateable surface and a second mateable surface of the valve block, and a plurality of the valve blocks are stacked and connected with mating the first mateable surface and the second mateable surface for establishing communication between the input ports and between the tank ports of the valve blocks.