Abstract: Between an air source and a first pressure chamber of a double-acting main cylinder having a length measurement sensor for measuring an acting position of a piston, a supply solenoid valve is connected; between the first pressure chamber and the atmosphere, an exhaust solenoid valve is connected; and between a second pressure chamber and the air source, a stop solenoid valve is connected. When a target acting position of the piston is inputted into a controller, the controller moves the piston to the target acting position so that a position measured by the length measurement sensor agrees with the target position by on-off controlling the solenoid valves. Upon reaching the target position, the piston is stopped and held in the stopped state by confining air within the pressure chambers.

Abstract: A valve arrangement includes a valve member, which rotates continuously in one sense. The generally cylindrical head of the valve member, within the housing, is formed to co-operate with various ports to create reciprocation in the actuator. It is preferred to provide some vibration of the valve member, to assist in overcoming the effects of friction.

Abstract: A position control system is used for controlling a fluid operated cylinder having at least one fluid chamber defined by a piston located within a housing for movement between first and second end limits of travel. The system includes at least two electrically actuated proportional flow control valves connected to each port of the cylinder for selectively and proportionally controlling fluid flow into and out of the at least one chamber. At least one pressure sensor is provided for measuring fluid pressure with respect to each chamber. At least one discrete position sensor is located adjacent a midpoint of the cylinder for sensing a discrete centered position of the piston. A controller includes a program and is operably connected for controlling actuation of the at least two valves in response to pressure measured by the at least one pressure sensor and location measured by the at least one position sensor.

Abstract: A precision servo control system for a pneumatic actuator has a piston positionable over a stroke of the pneumatic actuator using a supply of pressurized gas. A brake and a sensor system are connected to the actuator and to the servo control system. The servo control system operates to initiate the forward thrust from the pressurized gas to move the piston along the stroke. When a braking point along the stroke is determined, the servo control system initiates a reverse thrust from the pressurized gas while maintaining the forward thrust and simultaneously begins to selectively apply the brake to stop the piston within a predetermined tolerance of a desired stopping position.

Abstract: A precision servo control system for a pneumatic actuator has a piston positionable over a stroke of the pneumatic actuator using a supply of pressurized gas. A brake and a sensor system are connected to the actuator and to the servo control system. The servo control system operates to initiate the forward thrust from the pressurized gas to move the piston along the stroke. When a braking point along the stroke is determined, the servo control system initiates a reverse thrust from the pressurized gas while maintaining the forward thrust and simultaneously begins to selectively apply the brake to stop the piston within a predetermined tolerance of a desired stopping position. The precision servo control system is easily programmable in a manner similar to that of a control system for electrical actuators. The precision servo control system can maintain the predetermined tolerance even under changing loads, long stroke lengths or vertically oriented stroke directions.

Abstract: A method and an apparatus for controlling the function of all kinds of reciprocable power machines which are actuated by pneumatic, hydraulic of any other pressure fluid, irrespective if the machines are of rotary or axially operating type, in which the active power stroke is accomplished using full power of pressure fluid against a reciprocatable piston (2) in the active air pressure chamber (10, 12), and in which the reversing of the direction of operation is made by alternatingly supplying pressure fluid to the opposite air pressure chamber (12, 10) of the machine. A valve poppet (6) having several channels alternately places one of the pressure chambers (10, 12) of the reciprocatable fluid actuated machine (1, 2) under full pressure, builds up a certain counter pressure in a pressure chamber which is, at the actual moment, inactive, and evacuates the pressure from an inactive pressure chamber of the fluid actuated machine.

Abstract: A fluid controlled switching unit includes a valve block; a guide bore provided in the valve block; first and second work chambers provided in the valve block and spaced from one another; first and second cylinder bores provided in the valve body; and a plunger rod guided in the guide bore for reciprocating motion therein along a displacement path. The plunger rod has first and second piston faces situated in the first and second work chambers, respectively, and exposed to fluid pressure prevailing therein. The first and second piston faces move in the first and second cylinder bores, respectively. A valve body is attached to the plunger rod for forming a unitary structure therewith. The valve body has opposite pressure faces as well as first and second opposite end positions determining opposite ends of the displacement path. The valve body, when situated in one of the end positions, is exposed solely unilaterally to fluid pressure at one of the pressure faces thereof.

Abstract: An end dampened working cylinder for a fluid which serves as a fluid power medium for transmission of energy, the working cylinder comprising a main piston; control plungers carrying ring magnets and mounted on both sides of the main piston; springs form-locking the control plungers with the main piston and piston rod; sensors incorporated in a topside end and a bottom end and reacting to a contactless magnetic field, so that on approaching the ring magnet but at least on reaching a sealing rest position of the control plunger at each of the end stops a signal of a respective one of the sensors is generated and serves for controlling the fluid power, the control plungers sliding along the piston rod so as to provide adjustable and guaranteed sealing, outlet channels and a throttled flow-off channel, the control plungers serving as a shut-off component and valve for the outlet channels, so that when the control plungers rest on the topside end and the bottom end a dampening space is formed, from which a dampen

Abstract: A circuit is provided for the circulation of solvent to and from a valve having a movable component and a housing for movably housing the movable component. The movable component has a first orientation with respect to the housing in which it permits the flow of a valved fluid from the valve through a first port provided on the valve and a second orientation with respect to the housing in which it permits the flow of the valved fluid from the valve through a second port provided on the valve. The circuit includes a first passageway provided between the movable component and the housing. A third port is provided on the housing for the introduction of the solvent into the housing and a fourth port is provided on the housing for removal of the solvent from the housing. The first passageway couples the fourth port to the third port. The solvent is a solvent for the valved fluid. A reservoir is provided for the solvent, along with conduits for coupling the third and fourth ports to the reservoir.

Abstract: A pile driver arrangement including a reciprocal impact member connected to a piston rod which is also connected to a reciprocal piston located in a hydraulic cylinder having a lower rod end and an upper blind end. A hydraulic fluid tank and a pump for supplying hydraulic fluid from the tank to the lower rod end of the hydraulic cylinder to lift the piston and the impact member. A first hydraulic fluid conduit connecting the upper blind end of the hydraulic cylinder and the lower end of the hydraulic cylinder and a check valve to prevent the flow of hydraulic fluid from the lower end to the upper end of the hydraulic cylinder. A second hydraulic fluid conduit connecting the pump and the lower end of the hydraulic cylinder and a control valve in the second conduit for controlling the flow of hydraulic fluid from the pump to the lower end of the hydraulic cylinder.

Abstract: An automatic cushioning control apparatus for a cylinder of a working machine provides a quiet cylinder cushioning effect, causing little shaking of a vehicle body, without using a mechanical cylinder cushion.

Abstract: A pile driver arrangement including a reciprocal impact member connected to a piston rod which is also connected to a reciprocal piston located in a hydraulic cylinder having a lower rod end and an upper blind end. A hydraulic fluid tank and a pump for supplying hydraulic fluid from the tank to the lower rod end of the hydraulic cylinder to lift the piston and the impact member. A first hydraulic fluid conduit connecting the upper blind end of the hydraulic cylinder and the lower end of the hydraulic cylinder and a check valve to prevent the flow of hydraulic fluid from the lower end to the upper end of the hydraulic cylinder. A second hydraulic fluid conduit connecting the pump and the lower end of the hydraulic cylinder and a control valve in the second conduit for controlling the flow of hydraulic fluid from the pump to the lower end of the hydraulic cylinder.

Abstract: A linear drive device has a linear motor which consists of a piston, an output rod and a control rod. The two rods extend through the two end plates of the motor housing. The working or output rod is designed for the transmission of power to some structure. The control rod cooperates a sensor for positioning. The sensor and also a valve arrangement is integrated in the housing end plate associated with the control rod. The valve arrangement controls flow through pressure fluid duct provided in the housing end plate at the control end for actuating the linear motor.

Abstract: A modular digital actuator is formed by interconnecting a plurality of modules. Each of the modules includes a housing having a pair of different sized axially extending cylinder sections in which is received a T-shaped piston with the top of the T mating with the larger cylinder and the leg of the T forming a piston in the smaller cylinder. The leg of the T is hollow and forms a cylinder to receive an axially extending piston forming shaft to thereby provide three preferably different sized cooperating piston and cylinder areas, one formed in the cavity or hollows of the leg of the T, a second formed between the top of the T surrounding the leg of the T and the junction between the larger cylinder section and smaller cylinder section and the third formed in the smaller cylinder section between a closed free end of the smaller cylinder section and the leg of the T surrounding the piston forming shaft. The top of the T forms a piston wall in a fourth hydraulic cavity.

Abstract: A bi-directional snub valve provides two parallel fluid paths therethrough and means for restricting the fluid flow through each of the parallel paths to one preferred direction. A movable piston is provided with two land portions which selectively are movable into blocking association with two openings in a fluid chamber. Blockage of either of the two openings in the fluid chamber and the corresponding fluid flow path does not effect the ability of the alternate path to conduct a fluid therethrough. The bi-directional snub valve therefore is able to slow the flow of fluid therethrough as a movable object approaches its end-of-travel position. However, because of the nature of the two parallel flow paths, the movable object can be moved away from its end-of-travel position at full speed. A cam arrangement is used to move the piston of the snub valve in response to movement of the movable object.

Abstract: Small-sized engine operated by an expanding gaseous fluid, which comprises a cylinder (18), a piston (20) and an inlet valve (38), the upper parts of the cylinder (18) and the piston (20) cooperating momentarily with a perforated (29) resilient membrane (28) circumferentially secured to the cylinder (18) and performing the functions of a pneumatic seal temporarily.

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

Abstract: A pump jack of the type comprising a rocker arm pivotably mounted intermediate its ends on a support member, said rocker arm being divided by said pivot mounting into a sucker-rod limb and a drive limb wherein the improvement comprises a pneumatic motor pivotably attached to the drive support member and further pivotably attached to the mounting base of the pump jack to provide the power to reciprocate the pump jack. The working fluid of said pneumatic motor being natural gas which is available from the well casing of the well without any interference with the flow of the oil in the oil tube of the well thereby making use of an energy source available at any oil well without having to provide gasoline to drive a rotating type gasoline engine or electricity to drive an electric motor usually of the rotating variety.

Abstract: Control apparatus includes means defining a housing having a hollow and a piston device mounted for reciprocating movement in said hollow under the influence of pressure fluid applied alternately to each of opposite portions of its surface, characterized by means for transmitting a signal of a predetermined travel of said piston in one direction, said signal transmitting means being constructed and arranged to utilize applied pressure fluid in its signalling function.

Abstract: A fluid pressure servo detent mechanism for controlling movement of a piston within a cylinder including one-way inlet and outlet valves for controlling the fluid pressure within the cylinder with linkage means interconnecting the inlet and outlet valves and the moveable piston for simultaneously actuation thereof. A control or sensing rod is carried by the piston for movement therewith to provide a control element for articles to be controlled or to sense the position of the piston and the flow of fluid or receipt of pressure to the outlet may be utilized to determine the position of the piston and as a signal to additional equipment.

Abstract: A linear fluid-operated actuator includes a casing having a piston assembly slidingly movable in a main cylinder within the casing and provided with force transmitting means adapted to transmit the motion of the piston to the outside. A linear flow control assembly is provided including two valves which are each slidable within a valve cylinder positioned on either side of the main cylinder in coaxial relation and merging therewith. The valves are connected to each other for simultaneous movement and the size of the valve member, the extent of its movement and the position of an inlet and outlet port provided in each valve cylinder is such that the inlet in one cylinder is closed while its outlet is open, and the inlet of the other cylinder is open while its outlet is closed and communication between them is prevented. A retainer is provided for the valve assembly in either of its end positions and a spring is positioned between the piston and each valve.

Abstract: A pneumatically buffered drive system is provided which quickly moves a movable member, such as a press safety curtain or press bolster, a predetermined length in three sequential speed stages to prevent maximum acceleration from occurring at the end of the predetermined length. The movable member is coupled to a differential pressure piston which is initially pressurized on only one side of the piston to initiate movement. After traversing approximately half the predetermined length both sides of the piston are pressurized to decelerate the piston during the member movement for approximately the next third of the predetermined length. The remaining length is traversed with the decelerating pressure being vented to positively finish the motion along the predetermined path. In vertical moving members having significant mass such as press safety curtains, a higher pressure is used to decelerate the piston than the pressure used to drive the piston.