Abstract: A valve device has a valve housing (10), in which fluid ports (P, A, T) are provided and in which at least one valve piston (12, 14) can be moved longitudinally. The valve piston either separates at least two of the fluid ports (P, A, T) from one another or interconnects them as a function of its travel position. At least one latching device (16, 18) is provided for each valve piston (12, 14) for the detachable fastening of the respective valve pistons (12, 14) in one of its travel positions. Each latching device has at least one latching means (20), which can be brought into a latching position (22).

Abstract: A gas-powered drive system has a drive which includes a first chamber and a second chamber which are separated from one another by a piston. One of the chambers is connected to a gas source to drive the work element and the other chamber is connected via an exhaust air throttle to a gas sink by means of a reversing valve to movement of the piston. A control valve is assigned to the driving chamber through which the driving chamber can be filled with gas from the gas source. The opening cross-section of the control valve is set as a function of a control pressure.

Abstract: A diverter/mixing valve is provided that includes a main outer housing and a barrel assembly disposed inside the main outer housing. When actuated, an actuator rotates the barrel assembly between an open end inlet position where a first fluid stream flows into a first inlet port and a second fluid stream is blocked from flowing into a second inlet port, and an open side inlet position where the second fluid stream flows into the second inlet port and the first fluid stream is blocked from flowing into the first inlet port.

Abstract: A telescopic hydraulic cylinder is disclosed which has automatic air bleeding and fluid flushing features. A method of removing air from a hydraulic cylinder is also disclosed. A hydraulic circuit with for removing air from a hydraulic cylinder is further disclosed.

Abstract: A valve system for use with a cylinder having an extensible rod, includes a first valve assembly including a first inlet/outlet port, a check valve biased toward a closed state, the check valve having a check valve body at least partially receivable within a first port of the cylinder, a flow control valve positioned in series between the first inlet/outlet port and the check valve, and a first pilot port selectively communicable with a pressurized gas for opening the check valve. The valve system further includes a second valve assembly including a second inlet/outlet port, a second pilot port through which the pressurized gas must flow before being introduced to the first pilot port, and a valve body at least partially receivable within a second port of the cylinder, wherein the second inlet/outlet port and the second pilot port are integrally formed as a portion of the valve body.

Abstract: A method for operating a biopsy apparatus includes providing a cannula having a lumen, a proximal portion, a closed distal end, and an orifice located on a circumferential surface of the cannula, the orifice being configured to receive a tissue sample into the lumen of the cannula; providing a cutting sheath coaxially disposed with the cannula, the cutting sheath being configured to be movable relative to the cannula to selectively cover the orifice; providing a pressure chamber coupled to the proximal portion of the cannula, the pressure chamber configured to contain a pressure; providing a bifurcated valve assembly interposed between the cannula and the pressure chamber, the bifurcated valve assembly having a first valve and a second valve; operating the first valve to release the pressure into the lumen of the cannula; and operating the second valve to facilitate an inflow of air into the pressure chamber.

Abstract: An implement system for a machine having a stick member with a nose end and a mounting bracket is disclosed. The implement system includes a thumb pivotally connected to the nose end of the stick member, and a thumb actuator operatively connected between the mounting bracket of the stick member and the thumb to move the thumb between a fully retracted position and a fully extended position. The implement system has one or more of an RTK Factor, a TP Ratio and an ITO Ratio having values within ranges that allow installation of the implement system with the thumb actuator connected the thumb either directly or by a linkage assembly without changing the position of the mounting bracket on the stick member.

Abstract: A hydraulic system includes a first hydraulic circuit and a second hydraulic circuit. The first hydraulic circuit includes a hydraulic cylinder assembly, a pressurized fluid source, a fluid tank, and a metering control valve. The hydraulic cylinder assembly includes a cylinder, a rod, a head end including a head pressure, and a rod end including a rod pressure. The metering control valve includes a rod extension position, and a rod retraction position, and is fluidly connected to the head end, the rod end, the fluid source, and the fluid tank. The second hydraulic circuit includes a second circuit valve assembly selectively fluidly connected to the head end, the rod end, and the fluid tank.

Abstract: Provided is a hydraulic drive including a double-acting work cylinder with a piston having a first working surface effective in a retracting direction and a second working surface effective in an extending direction, wherein the first working surface delimits a first pressure chamber and the second working surface delimits a second pressure chamber, at least two different pressures being applicable to at least one of the first working surface and the second working surface for retracting or extending the piston into and out of the work cylinder, an actuator unit which optionally enables a throttled return flow of a hydraulic medium from the first pressure chamber delimited by the first working surface, and control means for triggering the actuator unit in such a way prior to a sudden acceleration of the piston due to a sudden force release.

Abstract: A device (100, 200, 200bis, 300, 300bis) for controlling a pilot pressure signal of hydraulic valves (3), for controlling the handling of gravitational loads (M), operating between two pilot lines (108, 109, 208, 209, 308, 309) between the valve (3) and a cylinder (1) adapted to sustain the load (M). The device (100, 200, 200bis, 300, 300bis) is a two-way and two-position valve for the communication between the cylinder stem-side pilot line (5) and the valve-side line (3) and is a valve which can take an open position and a partialized position, or anyway it never takes a closed position. The device (100, 200, 200bis, 300, 300bis) can take a position so that the fluid passage between the pilot lines (108, 109, 208, 209, 308, 309) is never completely closed.

Abstract: A railway brake cylinder includes a body (11?); a piston (13?) mobile relative to the body (11?) to act on a brake linkage and delimiting with the body (11?) a pressure chamber (10?) adapted to be supplied by a pneumatic pressure agent source; an auxiliary actuating member (26?) mobile relative to the body (11?) and the piston (13?), mechanically connected to manual operating elements to cause it to occupy either a rest position in which it is away from the piston (13?) or a pushing position in which it is in contact with the piston (13?); two orifices (73?, 51?) in fluid communication with the chamber (10?) and the atmosphere, respectively; and selective connecting elements (28?) between the two orifices (73?, 51?), the elements (28?) being mechanically connected to the auxiliary actuating member.

Abstract: An apparatus and method for providing enhanced vacuum to a brake booster of a braking system under certain operational conditions. Vacuum is stored in a reservoir and is controllably released to the brake booster to provide a brake booster vacuum level of at least a predetermined vacuum level threshold in order to avoid brake pedal performance issues being perceived by the driver of motor vehicles utilizing engines utilizing a supplemental brake assist system under conditions where the brake booster vacuum level is less than the predetermined vacuum level threshold.

Abstract: An axle locking cylinder structure is capable of enabling an operator of heavy construction equipment to stably carry out an axle locking operation since a sudden variation of the flow rate is prevented in the axle locking cylinder by draining a highly-pressurized flow rate slowly at the release of axle locking and supplying a flow rate quickly at the drive of axle locking. A highly-pressurized hydraulic fluid can be steadily drained from a cylinder chamber since an opening region between a poppet valve and a pilot flow path is enlarged so as to open the pilot flow path connected to the cylinder chamber during a relatively long time. A cylinder rod can be quickly expanded according to the manipulation of an axle locking switch by compensating a flow rate supplied to a cylinder chamber when the cylinder rod is expanded.

Abstract: A hydraulic circuit is disclosed that can include a flow control element, a pressure compensator connected via a pair of load sense lines to an inlet line and an outlet line, respectively, of a flow control element to provide a constant pressure drop across the flow control element, and a load sense line control valve installed in a load sense line to provide controllable resistance in a flow passage in opposite flow directions, the resistance in each flow direction being different. The load sense line control valve can include a restrictive orifice followed by a spring-loaded check valve in a first flow direction and at least one other restrictive orifice and a check valve in a second flow direction, the second flow direction opposing the first flow direction.

Abstract: A hydraulic circuit and method for operating a hydraulic device according to which fluid is passed from a source to the device while some of the fluid is passed to a valve that is adjustable to control the amount of fluid passed to it and therefore the amount of fluid passed to the device.

Abstract: A choke valve of the clutch release cylinder wherein the actuating oil is slowly discharged when the clutch pedal is released, and when the clutch pedal is depressed, resistance to the actuating oil is minimized for the actuating oil to be swiftly and smoothly supplied to the clutch release cylinder, thereby improving the responsiveness of the clutch and preventing occurrences of noise and vibration when the clutch is in operation.

Abstract: A flow control apparatus for a fluid cylinder for a workpiece holder includes a flow restricting member and a flexible sealing member. The flow restricting member defines a first passageway and a sealing surface. The flexible sealing member is positioned around the sealing surface. A second passageway is defined between the sealing member and a sealing surface of the flow restricting member when the sealing member is pushed away from the sealing surface in response to fluid flow in a first direction. When fluid flow is applied in the opposite direction, the sealing member moves to engage the sealing surface to substantially limit or preclude fluid flow between the sealing member and the sealing surface in the second direction. The fluid flow in the second direction is thus restricted to flow through the first passageway, thereby slowing or controlling the flow in the second direction.

Abstract: A method of individually adjusting auxiliary hydraulic valves for work vehicles is provided such that they provide different maximum flow rates for opposite flow directions through the valve. The valve is controlled by a flow rate control for setting a maximum flow rate and is also controlled by a proportional control input device having one range of positions for providing a corresponding first range of flow rates in the one direction, a central position for providing substantially no flow, and another range of positions for providing a corresponding second range of flow rates in the other direction.

Abstract: The present invention relates to a flow regulation device for mitigating over travel of a piston in a fluid operated tool. The flow regulation device includes a flow channel through which flows an operating fluid to be supplied to operate the piston within the tool and a movable flow restrictor within the flow channel. The flow restrictor has an internal fluid passageway for regulating the flow rate of the operating fluid being supplied to the tool to operate the piston. The flow restrictor also has a frustoconical portion which mates or seats against a portion of the flow channel as fluid is being supplied to operate the piston. A spring is provided to insure that the frustoconical portion seats against the mating portion of the flow channel. When the piston is retracted and operating fluid is being returned to a supply, the force applied by the spring is overcome and the flow restrictor is moved so that the frustoconical portion is unseated from the mating portion.

Abstract: A damper valve (70) located between a control valve (18) and a power steering motor (22) in a hydraulic power-assisted steering system (10). The damper valve (70) comprises a housing (72) having axially opposite first and second end portions (76 and 78) and an intermediate portion (80) interposed between the first and second end portions (76 and 78). The first end portion (76) is for fluid communication with the control valve (18) and the second end portion (78) is for fluid communication with the power steering motor (22). A flow restricting element (114) is located within the housing (72) and is movable through portions of the housing (72) including the intermediate portion (80) by fluid flow through the housing (72). The damper valve (70) further includes a biasing element (106) for restraining movement of the flow restricting element (114) toward the first end portion (76) of the housing (72).

Abstract: A balance of force acting on a pool 21 of a control valve 20 is expressed by (P1−P3)·A=F+f When it is assumed that a pressure difference P1−P2 before and after a throttle 42 is &Dgr;P12 to modify the above expression, an expression &Dgr;P12·A+(P2−P3)·A=f+F is obtained. According to the present invention, the force &Dgr;P12·A corresponding to the pressure difference &Dgr;P12 before and after the second throttle 42 of the first term of the left-hand side is applied to the control valve 20 as a force capable of canceling the flow force f at the first term of the right-hand side.

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: A hydraulic control circuit for controlling the operation of an attachment or tool associated with a particular work machine wherein such circuit includes an actuator for controlling the operation of the attachment or tool, a control valve operable to control fluid flow to the actuator, a fluid path communicating the control valve with the actuator, and a pilot signal control device positioned in communication with both the control valve and a pilot pressure source and having a signal port in communication with the actuator for sensing the pressure associated therewith, the control device being responsive to the pressure associated with the actuator and being operable for sending a control signal to the control valve when a pressure condition in the actuator reaches a predetermined value, the control signal actuating the control valve so as to at least partially close such valve and maintain an operative pressure on the attachment actuator while, at the same time, decreasing the fluid flow through the control

Abstract: A manually controlled lifting device is provided including a pneumatic lifting drive, a lifting member, a load carrying means, a pressure source, a pressure line, a flow control device, a pneumatic pressure switch and a vent drive. The lifting member is arranged on the pneumatic lifting drive and is a load transmitting component of at least two parts. The load carrying means is attached to the lifting member for carrying a load. The pressure line has a first end and a second end where the first end is in communication with the pressure source and the second end is in communication with the pneumatic lifting drive. The flow control device is in communication with the pressure line and integrated between the two parts of the load transfer component and the pressure source. The flow control device automatically varies a cross section of flow in the pressure line in relation to a load acting on the load carrying means.

Abstract: A lifting cylinder unit (1) has a plunger design, and includes a stationary rod tube (2) having a longitudinal axis (3), two axial end regions, and an outer surface (26). A rod head (4) is arranged in one of the axial end regions of the rod tube (2), the rod head (4) being fixedly connected to the rod tube (2) and including a connecting bore (7). A cylinder tube (14) having two axial end regions and an outer surface (22) is arranged outside the rod tube (2). The cylinder tube (14) is designed and arranged to be movable with respect to the rod tube (2) in the direction of the longitudinal axis (3) of the rod tube (2). A cylinder bottom (15) is arranged in one of the axial end regions of the cylinder tube (14), and is fixedly connected to the cylinder tube (14). A guide bush (18) having an inner surface (23) and including a surface (30) for the application of a force is fixedly connected to the outer surface (26) of the cylinder tube (2).

Abstract: A speed controller has a pilot check valve having a first body which has a first fluid inlet/outlet port defined in an end thereof and a pilot port defined in an opposite end thereof. A flow control valve has a second body integral with the first body. A pipe joint has a third body which has a second fluid inlet/outlet port defined in an end thereof and, the third body being integral with the second body. A flow adjustment screw is disposed in the flow control valve and extends into a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port, for adjusting a rate of flow of a fluid under pressure in the fluid passage. A valve body is disposed in the pilot check valve for opening a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port in response to a pilot fluid pressure supplied from the pilot port.

Abstract: A speed controller has a pilot check valve having a first body which has a first fluid inlet/outlet port defined in an end thereof and a pilot port defined in an opposite end thereof. A flow control valve has a second body integral with the first body. A pipe joint has a third body which has a second fluid inlet/outlet port defined in an end thereof and, the third body being integral with the second body. A flow adjustment screw is disposed in the flow control valve and extends into a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port, for adjusting a rate of flow of a fluid under pressure in the fluid passage. A valve body is disposed in the pilot check valve for opening a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port in response to a pilot fluid pressure supplied from the pilot port.

Abstract: A small-sized and inexpensive air cylinder with a cushion mechanism having a simple structure is provided. Therefore, discharge outlets for discharging cushioning air are disposed in positions closer to ends of the stroke than the openings of the ports in the cylinder tube, respectively, and check valves and throttling mechanisms are arranged in parallel between discharge outlets and ports, respectively. On the outer peripheral surface of the piston, one of the piston packing rings is disposed in one position which does not pass through the opening of the port while another of the piston packing rings is disposed in another position which passes through the opening but does not pass through discharge outlet, when the piston reaches the terminal ends of the stroke.

Abstract: A construction machine, e.g., a backhoe, has a chassis and a digging tool mounted for movement, e.g., swinging movement, with respect to such chassis. A machine hydraulic circuit includes a pump, a hydraulic actuator coupled to the tool for tool movement, and a directional valve between the pump and the actuator. In several specific embodiments, the circuit includes first and second flow restrictors coupled between the pump and the actuator. There is also a valve device for selectively disabling the second flow restrictor, thereby configuring the circuit to provide either of two maximum rates of tool movement. In other embodiments, the circuit uses a variable delivery, fluid-pumping power source and a load-sensing line coupled between the pump and the actuator. The valve device is in series with the load-sensing line and includes a restriction-free path and a flow-restricted path therethrough, thereby configuring the circuit to provide either of two maximum rates of tool movement.

Abstract: A throttle device for use with a hydraulic adjustment devices that have an input cylinder and an output cylinder and a hydraulic line filled with fluid connecting the output cylinder and the input cylinder, is arranged in the hydraulic line for establishing various throttle resistances to the flow of the fluid in both flow directions through the hydraulic line. The throttle device includes a disk with at least one boring and/or at least one passage channel. The disk moves back and forth, as the fluid flows, in both flow directions, and thereby strikes against a first stop in one direction and against a second stop in the other direction. The throttle device in the form of a disk in the movement space which is a transition from the hydraulic line to the supply line of the cylinder in its diameter, with a stop disk secured in the hydraulic line forming the second stop is economically advantageous. The disk that acts as the valve is distinguished by its low cost.

Abstract: An automatic depth control system is disclosed. The system includes a Console and remote Controller mounted in the tractor cab, power beyond Valving, and Depth Sensors, either ground contact or non-ground contact, mounted on the frame of the implement. The depth sensing system is provided to sense the actual penetration of an implement tool by determining the height of the implement frame above the ground. A circuit system is provided to receive the depth signal and to signal power beyond valving that will effect hydraulic corrections in order to maintain the select depth penetration. The Console includes an instrument panel having a toggle switch with AUTO, LOCK and MANUAL positions, an LED showing depth of tool penetration and a bargraph depicting variations from a desired depth and flashing lights on the bargraph to show depth corrections in process. The Console also includes a depth window in which no hydraulic correction would be made, a sensitivity switch, depth sensor switches and an UP/REPHASE switch.

Abstract: A speed controller has a pilot check valve having a first body which has a first fluid inlet/outlet port defined in an end thereof and a pilot port defined in an opposite end thereof. A flow control valve has a second body integral with the first body. A pipe joint has a third body which has a second fluid inlet/outlet port defined in an end thereof and, the third body being integral with the second body. A flow adjustment screw is disposed in the flow control valve and extends into a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port, for adjusting a rate of flow of a fluid under pressure in the fluid passage. A valve body is disposed in the pilot check valve for opening a fluid passage which interconnects the first fluid inlet/outlet port and the second fluid inlet/outlet port in response to a pilot fluid pressure supplied from the pilot port.

Abstract: A pneumatic cylinder for actuating fume extraction valves in fume and heat extraction plants has a piston (2) that may be actuated from both sides with at least one working surface and that can be made to slide by pressurised air in a cylinder (1) with at least one working chamber (4), as well as an energy accumulator with regulating means. The regulating means can be controlled by control means to open or keep open the fume extraction valves. In order to obtain a compact pneumatic cylinder for a fume and heat extraction plant which is easy to install, a storage chamber in which air or pressurised air is stored as compressible pressure medium is provided as energy accumulator. The storage chamber is in communication with a compression surface (7) of the piston (2), at its side opposite to the working surface (7), so that pressure medium may flow between the storage chamber and the compression surface (7).

Abstract: A fluid flow control for controlling the speed of a piston in a fluid power cylinder is disclosed in which the flow control is located within the confines of the cylinder and includes a rotatable disk having tearshaped slots for communication of the exhaust fluid through the disk and out of the cylinder through discharge ports. Rotation of the disk to selectively position greater or lesser width portions of the tearshaped slot relative to an exhaust discharge opening in the cylinder permits selective, variable adjustment and throttling of the exhaust fluid to control the speed of movement of the piston in the cylinder.

Abstract: A support element for supporting or holding a work piece on a mounting surface, for example in a machine tool, has a support or pin movably mounted in a housing. The pin is moved into contact with a work piece by an airstream, held in work piece contact by a hydraulic piston, and reset into a starting position by at least one spring, whereby the work piece is contacted gently under a manual throttle control of the airstream, but firmly held in place by hydraulic pressure.

Abstract: In a damper valve for use in a steering damper arrangement of a motor vehicle having a hydrostatic displacement motor for operating the vehicle steering mechanism wherein hydraulic fluid lines extending between the hydraulic motor and a servo-valve include the damper valve, the damper valve has a throttling arrangement which permits fluid flow in one direction and limits fluid flow in the opposite direction but permits essentially unlimited fluid flow in both directions as long as the pressure difference across the damper valve is below a predetermined threshold value so as to permit unrestricted normal steering movements of the vehicle steering system, but dampen shock movements thereof.

Abstract: An apparatus selectively supplies a source of pressurized fluid to a load device and selectively exhausts pressurized fluid from the load device. The apparatus includes a first housing for defining a longitudinally extending aperture communicating through first, second, and third passages with spaced first, second and third external surface portions of the first housing. A valve spool is engageable within the first aperture for longitudinal movement between a first position communicating the second passage with the third passage and a second position communicating the first passage with the second passage. The valve spool is normally biased toward the first position. Modular port members are connectable to the first, second and third spaced external surface portions for connecting the first passage to a source of pressurized fluid, the second passage to the load device, and the third passage to an exhaust port.

Abstract: A valve for a motor vehicle power steering gear including a tubular valve body having a plurality of internal lands, a valve spool rotatable inside of the valve body having a plurality of external lands, and a plurality of metering flats on the external lands which cooperate with linear edges of the internal lands in defining a pair of series connected metering orifices in a fluid flow path through the rotary valve from a pump to a reservoir. When the series connected metering orifices are fully closed, the effective circumferential overlap between the internal and external lands which prevents leakage from the pump to the reservoir is the sum of the circumferential overlaps at the individual metering orifices.

Abstract: A pneumatic cylinder, especially for a spot-welding machine, has a sleeve valve mounted on the piston rod. The sleeve valve provides a venting valve for dumping pressure from a return chamber at the end of the forward stroke, and a progressive restrictor to close off a forward chamber and provide cushioning at the end of the return stroke.

Abstract: A pneumatic circuit prolongs a pneumatic valve opening time using an accumulator with two quick exhaust type valves in series while providing a rapid valve closing time. This structure and method is self-contained and amenable to retrofit in existing installations without any external connections. Slow opening is achieved by routing inlet gas pressure simultaneously to an accumulator and the operating cylinder of the valve to be opened. A tortuous piping path and increased volume to be pressurized due to the addition of the accumulator substantially reduces the isolation valve opening time, thereby eliminating problems associated with quick opening of a pneumatic valve. When the pneumatic valve needs to be closed quickly, slight venting toward the inlet valve immediately causes the quick exhaust valves to vent their downstream pressure. The accumulator then vents through its quick exhaust valve while separately the main quick exhaust valve quickly vents the air cylinder of the pneumatic valve.

Abstract: A valve for slowly starting an actuator includes a block having an inlet port, an outlet port, and a passage providing communication between the inlet and outlet ports. A first valve body is disposed in the passage for selectively opening and closing the passage, and a second valve body is disposed downstream of the first valve body with respect to the passage for selectively opening and closing the passage. A needle valve is disposed in the block parallel to the second valve body between the passage and the outlet port for restricting the fluid under pressure discharged from the outlet port. The second valve body has a passage defined therein and communicating from one end to the other end thereof, and first and second pressure-bearing surfaces on the one and other ends, respectively, the first pressure-bearing surface is wider than the second pressure-bearing surface.

Abstract: A flow compensator valve for use in a hydraulic system which includes a cylindrical body having inlet and outlet ports, and a slidable, spring-biased hollow piston insert disposed within a center bore of the body, which insert has a plurality of ports for flow control depending on the position of the insert as it reciprocates axially within the center bore of the valve body. In a preferred embodiment, the valve is used in connection with a hydraulically actuated lift which is particularly useful for assistance of handicap persons for vans and mass transit vehicles. The axially-reciprocable, spring-biased flow rate controlling insert has a small central axial bore for slow lift movement in the loaded condition and at least one larger transverse bore, which when exposed, permits flow therethrough for faster movement of the lift in the unloaded condition.

Abstract: A motion control system for hydraulically operated lifting devices. The system provides for the dynamic weighing of a loaded container by controllably directing hydraulic flow through a bypass chamber of a two-way valve. An analog output signal is generated by a hydraulic pressure transducer fluidly communicating with the two-way valve or by a tensiometer mounted on the arms of the lifting device. The two-way valve further provides a second bypass chamber which receives fluid under gravity from the lift circuit line of the hydraulic cylinder for controllably lowering the lifting device. The pressure transducer or tensiometer generate an analog signal proportionate to the weight being lowered and whereby the hydraulic fluid is returned to the reservoir of the hydraulic system independently and downstream of the main operating valve.

Abstract: Hydraulic control systems are useful for controlling actuation of hydraulic motors. Some such systems use spool type valves while other systems use poppet type valves, both of which have their advantages and disadvantages. The present hydraulic control system is a hybrid system utilizing a combination of both a spool type control valve and poppet type control valves in a single work circuit. Specifically, a spool type control valve has an inlet port connected to a variable displacement pump and a pair of flow amplifying poppet type valves are serially disposed between a pair of motor ports of the spool type valve and a pair of actuating chambers of a double acting hydraulic motor. The spool type control valve is operative to control pump-to-motor flow while one of the poppet type valves is operative to control motor-to-tank flow.

Abstract: A motion control system for hydraulically operated lifting devices. The system provides for the dynamic weighing of a loaded container by controllably directing hydraulic flow through a bypass chamber of a two-way valve. An analog output signal is generated by a hydraulic pressure transducer fluidly communicating with the two-way valve or by a tensiometer mounted on the arms of the lifting device. The two-way valve further provides a second bypass chamber which receives fluid under gravity from the lift circuit line of the hydraulic cylinder for controllably lowering the lifting device. The pressure transducer or tensiometer generates an analog signal proportionate to the weight being lowered and whereby the hydraulic fluid is returned to the reservoir of the hydraulic system independently and downstream of the main operating valve.

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: A speed control device for a pneumatic cylinder of the invention is characterized in that a speed control of the pneumatic cylinder can be changed from air pressure to air mass flow by a two-way valve and an airflow control valve. Therefore, an ordinary and low moving speed of a load is maintained even if the load changes its speed or stops moving, and thus any accidents caused by a change of the moving speed of the load are prevented beforehand. Additionally, since in this invention only a two-way valve and an airflow control valve are added to a conventional pneumatic cylinder and high relief type pressure reducing valve, the device of the invention is simply constructed and has a wide variety of usage. Furthermore, since the device of the invention is provided with a pressure accumulator and a checking valve, the pneumatic cylinder can be stably controlled even when the load moves at a high speed.

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 brake booster includes a housing in which a constant-pressure chamber and a variable-pressure chamber are defined by a power piston. An input rod is operatively connected to one end of the power piston and receives an input force. A valve is provided in the power piston and operatively connected to the input piston so as to open upon receipt of the input force in such a manner that the differential pressure between the chambers moves the power piston. An output rod is operatively connected to the other end of the power piston. A wall member is provided across which a first auxiliary chamber at a side of the variable-pressure chamber and a second auxiliary chamber formed at a slide of the constant pressure are formed. An orifice passage connects the variable pressure chamber and the first auxiliary chamber.

Abstract: The invention discloses a controlled connector-adjuster permitting two different speeds in the same stroke of a double-acting pneumatic pressure cylinder.In the absence of a control signal at the orifice (13) of the apparatus, the escape pressure from the cylinder (30) effecting its rod extension stroke, finds the return valve (14) closed and holds the piston (2) against the stop (9) whose adjustment defines a first flowrate between the needle valve (15) at the end of the piston and its seat (16), which flowrate corresponds to the high speed. The arrival of a pressure signal into the chamber (6) causes piston (2) to move until it abuts on a second screw (7) whose adjustment permits a second smaller flowrate than the first one and which thus determines the second speed.