Abstract: In a pneumatic actuator for setting a control armature, a first working chamber and a second working chamber are pneumatically separated from each other by a moveable dividing wall to which the control armature is coupled in a force-transmitting manner. The dividing wall, in case of a pressure difference between the working chambers, is displaced in a first control direction. A positioner is adapted to output at least one pneumatic control signal to the first working chamber. The first and the second working chambers are pneumatically connected to each other via a pneumatic short-circuit duct with a balancing valve disposed in the short-circuit duct for at least one of closing or opening the short-circuit duct. The balancing valve is driveable by the positioner such that in case of a certain operating condition, the balancing valve pneumatically short-circuits the first and the second working chamber for achieving a pressure balance between the chambers.

Abstract: The invention relates to a double-acting pump system for use in moving a fluid. The pump system includes a means for inputting power at a location remote from the double-acting pump. The system allows for manual power input, such as through a local pumping unit. The double-acting pump may define an interior volume and include a first end chamber in fluid communication with the local pumping unit, a second end chamber in fluid communication with the local pumping unit, a central chamber having a separating section, and a driving element (e.g., a double-ended piston) slidably located within the interior volume of the double-acting pump. The separating section may include an inlet valve section (e.g., two inlet valves) and an outlet valve section (e.g., two outlet valves).

Abstract: A tool coupler assembly for a machine is disclosed. The tool coupler assembly may have a coupler frame, a first latch, a second latch, and a hydraulic actuator connected to move the second latch relative to the first latch and the coupler frame. The hydraulic actuator may have a first chamber, a second chamber, and a pressure valve with a check element movable to allow a flow of fluid into the first chamber based on a pressure of fluid in the first chamber, and a pressure regulating element movable to allow a flow of fluid out of the first chamber based on a pressure of fluid in the second chamber. The tool coupler assembly may additionally have a first pilot passage configured to communicate fluid from the second chamber with the pressure-regulating element, and a second pilot passage configured to communicate fluid from the first chamber with the pressure-regulating element.

Abstract: A hydraulic apparatus has a cam body rotatable about an axis and with at least two mirror image involute cam surfaces on opposing sides of the axis. Hydraulic actuators on opposing sides of the axis have a linearly extendable ram and a hydraulic cylinder. A fluid supply line is provided for delivering a pressurized fluid equally to each of the cylinders. A pressure relief or flow control valve is associated with each of the hydraulic cylinders and is operable to selectively assume a closed position to retain fluid or assume an open position to release fluid from the hydraulic cylinders. A control can operate the pressure relief valves between at least the closed and open positions, to move the rams out of and in to the cylinders to rotate the cam body about the axis with controlled torque. A robotic, prosthetic or orthotic and a method for applying torque to a body are also disclosed.

Abstract: A hydraulic actuator for pump control is disclosed. The hydraulic actuator includes two hydraulically isolated chambers for actuation in one direction and two hydraulically isolated chambers for actuation in an opposite direction. Each of the four chambers is connected to a source of high pressure fluid by an electronically controlled pressure reducing valve.

Abstract: The invention relates to a hydraulic pump or hydraulic motor having an orbiting cardan shaft. The hydraulic pump or motor includes a housing having an end cover and a port plate. The cardan shaft is mounted in the housing and extends through the port plate. A rotation speed sensor is fixed to the port plate and includes a sensor probe obtaining its signal from the orbiting cardan shaft. A piston may be in contact with the cardan shaft and moving forward and back due to the orbital motion of the cardan shaft. The sensor probe then obtains its signal from the movement of the piston.

Abstract: A reciprocating linear motor powered by one directional fluid flow is provided, having small external diameter, optimized for length, with few moving parts and effective seals, low mass and thus low inertia in direction changes. The motor provides reciprocating linear powered motion for use by attached equipment such as a pump, chisel, hammer, valve, or other machine requiring such power.

Abstract: A method for actuating a shift cylinder (1) of an electro-pneumatic control unit for the gearbox of a motor vehicle. The gearbox comprising a main gearbox, a group gearbox or other shifting elements with detents in at least one of a neutral position and/or a final position(s). The shift cylinder (1) is prefilled with a pressure below the detent actuating force, prior to a gearshift phase of the control unit, such that the gearshift time is reduced.

Abstract: A fluid-powered cylinder for displacing an object with respect to a support surface is disclosed. The fluid-power cylinder includes a fabric enclosure having ends fastened to two end caps and forming an expandable and contractible chamber therein. The chamber has a port for selectively disposing an incompressible fluid in the chamber. The chamber is adapted to displace the object to a first position with respect to the support surface and to displace the object to a second position with respect to the support surface.

Abstract: A pneumatic motor includes a cylinder, a rotor and a drive shaft. The cylinder includes a cylinder body having two ends, a first cover and a second cover. The first cover is mounted on one of the ends of the cylinder body and has a first bearing housing, a first bearing and a first blocking ring. The first bearing is mounted in the first bearing housing and has an annular clearance. The first blocking ring is mounted between the first bearing housing and the first bearing and covers the annular clearance of the first bearing. The rotor is mounted rotatably in the cylinder body. The drive shaft is mounted securely through the rotor. When compressed air is expelled from the cylinder body, the compressed air does not blow lubricants out of the first bearing because the first blocking ring closes the annular clearance.

Abstract: An anchor structure of a rotation directing valve is used on a housing made from a composite material for pneumatic tools. A valve bushing in the housing is set under a cylinder. The rotation directing valve held by the valve bushing is to control a pneumatic motor in clockwise or counterclockwise rotation by moving it back and forth to alter the flow direction of compressed air. The anchor structure formed on the valve bushing anchors the rotation directing valve while the pneumatic motor rotates clockwise or counterclockwise.

Abstract: An actuator having two or more interconnected movement components, wherein the movement components are designed as linear actuators with substantially coaxial longitudinal axes or longitudinal axes that are parallel to each other and that are interconnected in longitudinal direction such that their linear movements are superimposed on one another, and such that at least one of the linear actuators can be stopped at one or several predetermined positions.

Abstract: A tank 16 and a main hydraulic pump 17 are connected to head side actuator chambers 13 and rod side actuator chambers 14 of hydraulic actuators 12 via conduits 21, 22. A direction control valve 18 and a quick drop valve 36 are connected to the conduits 21, 22. A hydraulic circuit is provided with an electromagnetic switch valve 42, which switches the quick drop valve 36 from a non-quick drop position 37 to a quick drop position 38. When switching the direction control valve 18 from a neutral position 23 to a lowering operation position 25, if the manipulation speed of a manipulation lever 33 exceeds a criteria speed, an excitation signal is output from a control device 32 to an electromagnetic switch valve 42 to quickly drop a blade 11, and the quick drop valve 36 is switched from the non-quick drop position 37 to the quick drop position 38.

Abstract: The invention provides a method and a system for moving an element, e.g. a rudder of a ship or a wheel of a vehicle. The element is moved by a hydraulic fluid. According to the invention, an operator indicates a desired movement, and in accordance with the desired movement, at fluid is provided from at least three fluid providers each providing a share of the fluid in parallel streams and only considering the desired movement not the shares provided by the other fluid providers. The invention allows continuation of a steering task even if one fluid provider is disabled, and the invention allows the continuation even without having to notice that one provider is disabled. Accordingly, the invention provides an improvement and simplification relative to the known hydraulic steering systems.

Abstract: An antagonistic fluid control system, wherein the system may comprise multiple antagonistic pressure control valves operable with a single actuator, or multiple pressure control valves operable with respective antagonistic actuators. The pressure control valves are configured to provide functional and efficiency advantages, and operate together to provide several operating or valving states. A first valving state comprises an active valving state configured to actively control the movement of the load. A second valving state comprises an inactive actuation state, wherein either the return and pressure ports of one pressure control valve are closed, or only the return ports of one pressure control valve are opened, to allow the other pressure control valve to operate in an active valving state. A third valving state comprises a passive valving state, wherein the pressure control valves are operated in a slosh mode configured to allow the load to freely move or dangle.

Abstract: A fluid control or actuation system providing selective recruiting of actuators antagonistic to one another to provide variable output power, such as that used to drive a load. The actuators are intended to comprise different sizes, and to be operable with one or more pressure control valves capable of providing displacement of a non-recruited actuator without requiring active input to cause such displacement. Being able to selectively recruit different sized actuators to drive the load, and being able to displace non-recruited without active input, effectively incorporates a gearing function into the fluid control system.

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 control system of an industrial truck includes a first switch, a second switch and a hydraulic circuit. The first switch detects whether an operator sits down on a seat, and carries out a first operation based on the detecting result. The second switch detects whether a device for operating an actuator is operated, and carries out a second operation based on the detecting result. The hydraulic circuit is used for operating of the actuator. The hydraulic circuit includes: a control valve, a first circulating line, a hydraulic line and a drive lock valve. The control valve includes a spool that position is changed by the device. The first circulating line includes the control valve, through which the hydraulic fluid circulates. The hydraulic line connects the spool with the actuator, through which the hydraulic fluid passes. The drive lock valve is provided for the hydraulic line, and blocks the hydraulic line, based on the first operation and/or the second operation.

Abstract: There is provided a flow divider system in a hydraulic circuit for a work machine including a boom cylinder and a bucket cylinder. The flow divider system divides a pressured oil drained from a one-boom cylinder into an other-bucket cylinder and a tank via a first orifice, a second orifice and a flow dividing valve, maintaining a specified pressure difference between pressures downstream the first and second orifices. The first and second orifice are configured of a variable orifice respectively, and in the event that the oil flow from the one-boom chamber decreases, respective opening degrees of the first and second orifices are controlled so as to be reduced. Accordingly, changing of a divisional ratio of oil flow can be suppressed properly regardless of a small oil flow drained from the boom cylinder.

Abstract: A drive for a movable part, such as a mold closure platen, includes two hydraulic cylinder-and-piston units defining first and third pressure chambers in a first of the hydraulic units and defining fourth and fifth pressure chambers in a second of the hydraulic units, and wherein the piston of one of the hydraulic units is a stepped piston defining a second pressure chamber, thereby providing five pressure chambers. An arrangement of valves provides for selective coupling of hydraulic fluid among the pressure chambers whereby pressure medium is forced from one of the hydraulic units, during an advance of its piton, to the other of the hydraulic units.

Abstract: The invention concerns a driving device, particularly a lifting device for a working vehicle, with a hydraulic drive, in the form of a motor with a first connection and a second connection, a pump, a control valve arrangement between the pump and the drive, and an operating device with at least one operating element with a setting area, with which at least one parameter of the drive can be set. It is endeavoured to provide a simple manner of extending the functionality of the lifting device. For this purpose, it is ensured that the control valve arrangement is optionally controlling the drive to be single-acting or double-acting and the setting area has a first section, in which the drive is controlled to be single-acting and a second section, in which the drive is controlled to be double-acting.

Abstract: A joystick controller is provided in a hydraulic circuit having a pair of hydraulic actuators and oriented with respect to the operator so that movement of a control lever of the joystick controller relative to a reference axis oriented perpendicular to the operator results in control signals being generated and delivered to the first and second main control valves so that the respective cylinders are moved in a direction that is intuitive to the operator. For example, forward movement of the control lever results in both hydraulic actuators moving in the same forward or downward direction and movement of the control lever rearwardly results in both actuators moving in the rearward or upward direction. Likewise, movement of the control lever along an axis that is oriented forty five degrees from the reference axis results in control of one of the actuators independent of the other one.

Abstract: Hydrophilic polymer actuators for an implantable device and methods of forming such actuators are provided, wherein the hydrophilic polymer actuators are actuated by the hydration and dehydration of a hydrophilic polymer material.

Abstract: A control system for controlling a tiltable wheel truck of a main landing gear includes an auxiliary strut, a ground mode system operably connected with the aircraft for detecting and providing signals indicative of when the aircraft is on the ground; a takeoff mode system operably connected with the aircraft for detecting and providing signals indicative of when the aircraft is operating in a throttled-up mode; and an auxiliary strut control unit operably connected with the ground mode sensor, takeoff mode sensor, and auxiliary strut. The auxiliary strut control unit is operable to issue a lock-up command signal to the auxiliary strut upon detecting signals from the sensors indicating that the aircraft is on the ground and that the aircraft is operating in a throttled-up mode, whereby the auxiliary strut is caused to lock up during a takeoff roll but is unlocked during other operating modes of the aircraft.

Abstract: A system for remotely controlling an undersea device. The system employs a gas-pressurized liquid reservoir that can be recharged from at least one replaceable gas bottle. A pressure-regulating valve is employed to control the pressure of the liquid leaving the reservoir. A number of one-shot units, each in the form of a squib-actuated valve coupled with a piston accumulator, are employed to create a hydraulic pilot for a hydraulic direction control valve. The control valve functions to direct pressurized liquid from the reservoir to a hydraulic actuator or other type of hydraulic device.

Abstract: A vertically oriented hydraulic power unit for an elevator drive includes an outer tank for drive fluid and an inner tank for fluid used to submerge and cool a motor, the fluids being exchangeable to maintain temperature in the inner tank at or below a specified maximum temperature. Oil returning from an elevator piston is fed into said inner tank to keep the inner tank sufficiently cool.

Abstract: A control system is provided for use in a hydraulic system to provide a simple arrangement with a limited number of elements that bypasses the system flow in the event of an electrical malfunction in the system and further allows other hydraulic circuits to operate even if one or more of the hydraulic circuits have experienced an electrical malfunction. The subject arrangement uses an electro-hydraulic fluid flow control valve mechanism in conjunction with directional valve mechanisms that have at least three functional positions and are controlled by associated electrically controlled displacement control mechanisms in response to receipt of electrical signals from an electrical controller.

Abstract: A method for controlling a hydraulic motor with a hydraulic valve comprising an inlet section which includes a pump and tank connection and a maneuvering section having a slide (B1) and a load signal system (L1, L2, L3). The hydraulic valve also includes two regulating constrictions (S3, S4) which can be connected to and from a motor (C), such as a hydraulic piston-cylinder device. The maneuvering slide (B1) also includes a load level detecting constriction (S2) and a load signal drain (S5), and the pump generates an idling pressure. When maneuvering the maneuver slide (B1), the load signal Ps of the load signal system is increased by a further constriction (S1) located between the pump connection and that side of the load detecting constriction (S2) that has the higher pressure during the maneuvering process.

Abstract: A method of manufacturing a tandem brake booster by selectively choosing a front shell having a first cylindrical body with first effective diameter, a transition shell having a second cylindrical body with a second effective diameter and a rear shell having a third cylindrical body with a third effective diameter. The cylindrical body of the transition shell is an integral component of an end wall which separates the interior the resulting tandem brake booster. The end wall has a peripheral ledge with a flange extending therefrom and a groove located on the flange connected to the second cylindrical body. An annular surface on the first cylindrical body is crimped into the groove on the flange while a corresponding annular surface on the second cylindrical body is crimped onto the third cylindrical to join the transition shell with the rear shell to form an integral unit.

Abstract: An improved fluid controller (15) is provided having both rotary valving (47) actuated by the steering wheel (17), and axial valving (49) controlled by an electro-hydraulic valve (113) in response to a correction signal (31). In one embodiment, both the rotary valving and the axial valving are achieved by a primary valve member (63) and a follow-up valve member (65), and both the rotary and axial valving can be actuated simultaneously. Also disclosed is a logic control system for closed-loop control of the electro-hydraulic valve, whereby performance problems such as self-steering, wander, drift, and others are substantially eliminated.

Abstract: In a process for controlling an actuator which can be adjusted by means of a proportional valve, the proportional valve is controllable by means of two control magnets with control pulses acting in opposite directions. A phase angle between the control pulses is varied as a function of at least one control variable (command variable, correction variable or difference between the amplitudes or pulse durations of the control pulses), i.e. it is reduced as the control variable increases. This measure prevents undesired vibrations of the actuator and resulting noises.

Abstract: A safety valve which prevents the discharge chute from rapidly falling due to a sudden loss of hydraulic fluid pressure. The valve is located between the chute lift cylinder port and hydraulic system hose. The valve is actuated when the flow leaving the chute lift cylinder exceeds a predetermined flow. The valve immediately stops the hydraulic fluid from leaving the chute lift cylinder maintaining the position of the discharge chute.

Abstract: A setting method for minimizing the closure travel of a central valve in a master cylinder is proposed, wherein, after the assembly of all internal parts except the stop (10), the internal parts having a position which corresponds to the inoperative position, the distance (y) between that end of the axial extension (12) which is on the actuating side and a fixed point is measured and wherein then, in dependence upon the measured distance (y) a stop (10) is chosen such that the desired closure travel (x) between the closing body (13) and the valve seat (14) of the central valve is established. By means of said method the closure travel of the central valve (x) is exactly adjustable irrespective of the tolerances of other component parts or a preceding power booster.

Abstract: In the booster are mounted movably a hollow booster piston (20) and a control rod (30) carrying a plunger (28) seated in the piston (20), the rear end of the plunger (28) forming a first annular valve seat (28a) concentric with a second annular valve seat (20a) carried by the booster piston (20), the first valve seat (28a) and second valve seat (20a) interacting with an annular shutter (34) carried by the booster piston (20), and a reaction disk (48) being interposed between an annular front face (20b) of the booster piston (20) and a rear face of a push rod (46). The process for adjusting the value of the pump of the booster comprises the following steps:applying to the push rod (46) a force equal to the boost force corresponding to the desired jump of the booster,moving the seat (20a) of the booster piston (20) away from the shutter (34),putting the front face of the plunger (28) and the rear face of the reaction disk (48) into contact and maintaining this contact during the next step.

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

Abstract: A dual servo actuation system is automatically equalized or rigged by electronic control circuits. A static auto rigging bias is applied to one or the other, or both, of a pair of electro hydraulic servo valves that respectively control two hydraulic actuators driving a common member, such as an aircraft control surface. An auto rigging bias, which substantially eliminates force fight, is automatically generated and stored as a fixed quantity prior to use of the system for control of the common member. With a zero commanded output of the two actuators, a difference of differential pressures at the actuators is obtained and caused to change the number in a counter as long as the difference exceeds a threshold. The counter number, while it is above the threshold, is continuously applied as a bias signal to decrease the force fight, and the number in the counter is stored as a fixed bias signal when the force fight indicated by the difference of differential pressures drops below the threshold.

Abstract: The process is for adjusting the value of the jump of a brake booster, in which are movably mounted a hollow boosting piston, a control rod carrying a plunger seated in the piston and a push rod, boosting means being controlled as a result of a forward movement of the plunger and their effect being to move the piston forwards, a reaction disc being interposed between an annular front face of the piston and a rear face of the push rod, the booster being intended for actuating a master cylinder.

Abstract: A hydraulic control method which includes a step of changing the time rate of introduction per a predetermined unit time of pressurized oil into an oil passage connected to a hydraulically-operated load device, such as a clutch of an automatic transmission, from a first time rate to a second time rate, thereby changing the time-based average oil pressure inside the oil passage from a first oil pressure value to a second oil pressure value. The time rate of introduction of the pressurized oil into the oil passage is changed from the first time rate to the second time rate via a third pressurized oil introduction time rate corresponding to a third oil pressure value different from the first and second oil pressure values. If the second oil pressure value is greater than the first oil pressure value, the third pressurized oil introduction time rate is substantially 100%. If the second pressure value is smaller than the first, the third time rate is substantially 0%.

Abstract: The setting of the dead travel of a servo-motor for assistance during braking is carried out in the factory during its assembly. For this purpose, a subassembly (68) comprising the piston (20), the operating pushrod (30) and its plunger (28), the valve head (34), the springs (38, 40) and the fixed (44) and tilting (50) keys, is placed in a setting sleeve (70). A load (F1) is exerted on the front face of the piston (20) sufficient to maintain a bearing surface (20b) permanently against a reference surface (70a) formed on the sleeve, and the pushrod (30) is freed from the action of the spring (40) by means of a fork (70a) formed on the sleeve, and the pushrod (30) is freed from the action of the spring (40) by means of a fork (72), after having pushed the plunger (28) up against the valve head (34) by applying a load (F3), the movement (.DELTA.) made by the mobile key (50) is measured between the reference surface (170a) and a shoulder formed on the plunger (28).

Abstract: A method and apparatus for reducing the intensity of the sound that accompanies a rapid decompression in a pressurized hydraulic system such as that of an injection molding machine. The apparatus includes a reduced area valve that interconnects the high pressure system with a low pressure system, with the valve connected with a tubular muffler so that high pressure fluid is initially released through the valve and into the muffler. The muffler includes a plurality of spaced apertures that face a rigid structural surface so that the high pressure fluid passing through the muffler issues from the several apertures and impinges on the rigid structure to dissipate the pressure shock accompanying decompression, and thereby modulate the intensity of the sound of decompression.

Abstract: A system for positioning equipment quickly and accurately over a plurality of desired positions by employing a "long move" mode of operation and a "short move" mode of operation to adapt the operation of the positioning system to variable and changing conditions. The system generally includes a microprocessor as the controlling means, a controlled valving means, a pressure source coupled to the valving means, an encoder sensing means and a positioning means defined by a pneumatic cylinder.

Abstract: A system which provides a vent reservoir to maintain a fluid level above the vent of the solenoid-actuated valves which ensures that the fluid passages are filled with fluid to provide rapid hydraulic response of the fluid system while allowing trapped air to automatically escape or vent.

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

Abstract: Electrically controlled combined valve/cylinder apparatus. The apparatus includes a housing having a cylindrical body and spaced first and second end walls closing the body. A cylinder is positioned inside the body and a piston is positioned inside the cylinder for reciprocal movement. A control ram connected to the piston extends through an aperture in the first end wall so that the piston is movable between a first position adjacent the first end wall in which the ram is extended and a second postion in which the piston is located adjacent the second end wall so that the ram is retracted. The apparatus further includes a cylindrical control sleeve positioned between and spaced from both the body and the cylinder. An inlet port tube is provided for supplying an electro-rheological fluid to the body while an outlet port tube is provided for discharging the fluid from the body.

Abstract: An apparatus for locking an wheeled table into a fixed location is disclosed. The base of the table is provided with both an electric motor coupled to a hydraulic pump and a manually operated hydraulic pump either of which may provide a source of pressurized hydraulic fluid. Extendable and retractable legs are provided on the base of the surgical table. Hydraulic cylinders disposed adjacent to each of the legs are provided with upper link members pivotally attached to the table's base and lower link members which are pivotally attached to the deployable legs. When pressurized hydraulic fluid is provided by the electrically driven or manually powered hydraulic pumps, the hydraulic cylinders disposed adjacent to the deployable legs are extended. Such extension is translated by means of the respective upper and lower link members into a vertical movement which lowers the supporting legs to fix the table in a specified location.

Abstract: A control system for airships and the like that incorporates optically encoded control signals and a compressed fluid power source to power a remote control station to decrease the susceptibility of the control system to uninterruption or disablement due to electromagnetic interference. The compressed fluid power source provides means of driving an electrical generator at a remote location to power the electrical portion of the control system at the remote location in addition to providing primary power for movement of the controlled devices.

Abstract: The invention relates to a method for the simultaneous actuation of a plurality of hydraulic consumers by means of intrinsically-safe electro-hydraulic valves. The consumers are connected by hydraulic directional control valves to a pressure line and/or a return line. These hydraulic directional control valves can be connected in a predetermined manner, via pre-control valves to a control line. The pre-control valves are pressureless, and possess electro-magnets with a current consumption of less than 50 milliamps. By connection of a series-connected electro-hydraulic directional control valve means, the pre-control valves are connected to the control line, and at the same time are hydraulically locked.

Abstract: A cushioning mechanism in a pneumatic cylinder utilizing a supplied air pressure, and a method of cushioning a piston in the pneumatic cylinder. Cushioning chambers are provided at opposite ends of a cylinder body of the pneumatic cylinder. Respective differential pressure valves and relief valves are provided between each of the cushioning chambers and an air supply. A cushioning member is disposed between each cushioning chamber and a cylinder bore. Air supplied under pressure from the air supply is stored in one of the cushioning chambers. When the piston is displaced to push the cushioning member, the air in the cushioning chamber is compressed to cushion the piston. As the cushioning member is moved a prescribed interval, the cushioning chamber is vented to atmosphere.

Abstract: The drive system for cells for fused salt electrolytic production of aluminum is supplied with compressed air via a compressed air network with compressor and compressed air reservoir. It comprises at least one working cylinder with piston and piston rod, a slide valve situated after the junction from the compressed air network, compressed air pipes and a microprocessor. During the thrust movement in the normal work cycle, the working cylinder forms a circuit together with a 5/2 channeling valve, a 3/2 channeling valve and the related compressed air pipelines; the said circuit is fed compressed air via a pressure reducing valve and the compressed air pipeline running from it. By briefly switching over the 5/2 channeling valve normal pressure can be employed and the positive chamber of the working cylinder evacuated, as a result of which the thrusting force supplied by the system can be greatly increased.

Abstract: A piston for a striker is displaceable in a cylinder and forms compartments on opposite sides which can selectively be connected by hydraulically controlled valve elements to a pump and to an accumulator. A hydraulic controller for the valve elements initially connects a compartment on one side of the piston to contribute the pressure from a respective compartment to the accumulator during a lifting operation, cuts off the valve element affording this pressure accumulation to brake the piston, and other such valve elements enable the accumulator to be charged with the piston in its raised position so that, upon triggering by the controller of the valve elements, the pressure which drives the ram is equal to the total pressure delivered by the accumulator and the pump to the piston.