Abstract: This industrial apparatus (2) comprises a pneumatic system (4), a first mechanical device (36) and a second mechanical device (38). The pneumatic system (4) includes: a first pneumatic actuator (6) for commanding the first mechanical device (36), a second pneumatic actuator (8) for commanding the second mechanical device (38), a pneumatic control valve (10) switchable between several states to command of the first and second actuators (6, 8). The control valve (10) comprises an actuation portion (56), movable in translation between: a resting position, corresponding to a first state (S1), a first pushed position, corresponding to a second state (S2), and a second pushed position, corresponding to a third state (S3). The first pushed position corresponds to an intermediary position between the resting position and the second pushed position.

Abstract: A cylinder acceleration mechanism includes a buffer tank that supplies and discharges oil to and from a bottom-side line that is connected to a bottom-side chamber of an actuating cylinder, and an inversion lever having an intermediate fulcrum as a rotation axis. The buffer tank includes a buffer chamber with a variable capacity achieved by a seal lid moving back and forth inside of a case, and extends and reduces a length of a coupling rod provided to the seal lid and projects from the case. A bottom-side branching line branched from the bottom-side line is connected to the buffer chamber. The actuating rod of the actuating cylinder and the coupling rod of the buffer tank are coupled to respective ends of the inversion lever. The actuating rod and the coupling rod extend and retract alternately with respect to each other as the inversion lever turns.

Abstract: A stepper motor including: a plurality of actuators, each having an actuation rod movable between retracted and expended positions, the actuation rod having an actuation pin movable along with the actuation rod; and a shuttle rotatable about a shaft, the shuttle having a plurality of pockets corresponding to the actuation pin of the plurality of actuators, the plurality of pockets being partially offset from the plurality of pins such that actuation of one or more of the plurality of actuators moves the actuation rod and corresponding actuation pin into a corresponding one of the plurality of pockets to rotate the shuttle about the shaft.

Abstract: The invention relates to a hydraulic manifold apparatus and system, connectable to a dual stage motor, for use in the topdrive of drilling operations. The hydraulic manifold is switchable between a low speed, high torque configuration and a high speed, low torque configuration. Valves within the manifold control the flow of working fluid through the manifold and into and out of the motor. Switching means are further provided to control the opening and closing of the valves. In the low speed, high torque configuration, working fluid enters each stage of the dual motor simultaneously, in parallel. In the high speed, low torque configuration, working fluid enters a first stage of the motor, returns to the hydraulic manifold, then enters a second stage of the motor, before returning again to the hydraulic manifold. Thus during high speed, low torque operation, working fluid enters each stage of the dual motor in series.

Abstract: A linear actuator includes a guide block constituting a guide mechanism. In the guide block, a pair of installation grooves are formed in a lower surface facing toward a cylinder main body. Ball circulation members having therein ball circulation holes are installed respectively in the installation grooves. Additionally, ball circulation passages through which balls circulate are provided. The ball circulation passages are made up from roll-reversing sections disposed on opposite ends of the ball circulation members, the ball circulation holes, second ball guide grooves formed in both side surfaces of the guide block, and first ball guide grooves of the slide table.

Abstract: An output system (100) for the extraction and/or output of plural masses (220), comprising a cylinder unit (300) made up of at least two double-acting cylinders (301, 304) each having a piston (303), displaceable by means of a piston rod (302, 305), for extraction and/or output of one of the masses (220) in each case, the piston rods (302, 305) being arranged parallel to one another and being connected to one another via at least one connecting element (307) in such a way that the connected piston rods (302, 305) are displaceable as a unit; and comprising a control unit (200) made up of at least two valves (201, 204) for controlling the entry and return of the masses (220) to the cylinders (301, 304).

Abstract: The invention relates to a liquid piston arrangement for compressing and expanding gases. The liquid piston arrangement includes a liquid piston which is embodied by a liquid level formed by a liquid in a high-pressure space and a stack of sheets with mutually spaced apart sheet metal plates which is supported in the high-pressure space dipping in the liquid and is sequentially flowed around by the liquid.

Abstract: A device controls the movement of a ring gate of a hydraulic machine between an open position and a blockage position. The device includes at least four cylinders, the rods of which are suitable for being connected to the ring gate at locations located on a perimeter of the ring gate. The device also includes at least two hydraulic members for synchronizing pistons, the hydraulic synchronization members being connected to the cylinders such as to form at least two groups. Each group encompasses at least two cylinders connected by at least one hydraulic synchronization member, two cylinders belonging to two separate groups not being connected by a hydraulic synchronization member.

Abstract: An output system (100) for the extraction and/or output of plural masses (220), comprising a cylinder unit (300) made up of at least two double-acting cylinders (301, 304) each having a piston (303), displaceable by means of a piston rod (302, 305), for extraction and/or output of one of the masses (220) in each case, the piston rods (302, 305) being arranged parallel to one another and being connected to one another via at least one connecting element (307) in such a way that the connected piston rods (302, 305) are displaceable as a unit; and comprising a control unit (200) made up of at least two valves (201, 204) for controlling the entry and return of the masses (220) to the cylinders (301, 304).

Abstract: A crank device and an adjusting device of a combustion engine. The system adjusts the cylinder pressure of the motor in accordance with the required power. Adjustment of the cylinder pressure takes place by changing the compression ration by means of the adjusting device (19). The adjusting device (19) changes an eccentric wheel (3) through an adjusting wheel (4) to a such position that a connecting rod (2) lifts a piston (1) to a desired distance from the combustion chamber head. The adjusting device measures the volume of the air entering the cylinder and adjust the compression ratio to be appropriate. The adjusting device also takes into account the speed of rotation so that the compression pressure increases or decreases to be appropriate.

Abstract: In various embodiments, cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the cylinder assemblies during expansion or compression of a gas.

Abstract: The mixed gas engine in accordance with the invention is used to obtain a power that is transmitted to a shaft to turn it, and it is made up of an oilbath body subassembly A containing a crankshaft-connecting rods-piston subassembly B, and over which is a cylinder unit subassembly C, a recuperator distributor body subassembly D containing a rocker shaft subassembly E, a camshaft subassembly F1 and another recuperator distributor subassembly G that also contains a rocker shaft subassembly H and a camshaft subassembly I, all connected to a pressurized circuit consisting of pressure pipes 164, a valve 165, a manometer 166, a bottle 167, and a compressor 168, known and not marked.

Abstract: A floating piston actuator for use with multiple hydraulic systems includes a housing and a piston assembly. The piston assembly includes an elongate shaft or ram, at least one secured piston coupled to the ram, and a set of moveable pistons moveably disposed within the housing chamber on the ram such that the set of moveable pistons are translatable relative to a longitudinal axis of the ram. The set of moveable pistons form at least three hydraulically separate actuator cylinders where each of the three hydraulically separate actuator cylinders are disposed in fluid communication with a corresponding pressurized fluid source. The floating piston actuator allows hydraulic redundancy while maintaining a similar length compared to existing multi-system actuators. The floating pistons can be arranged in multiple configurations to allow operation with a hydraulic system failure without force fight or binding and with a higher output force than conventional multi-system actuators.

Abstract: In various embodiments, pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the pneumatic cylinder assemblies during expansion or compression of a gas.

Abstract: Actuators, and corresponding methods and systems for controlling such actuators, provide independent valve control with a large initial or opening force.

Abstract: In various embodiments, pneumatic cylinder assemblies are coupled in series pneumatically, thereby reducing a range of force produced by or acting on the pneumatic cylinder assemblies during expansion or compression of a gas.

Abstract: A double-acting piston compressor (1) includes at least one cylinder (3) in which a double-acting piston (4) moves, the cylinder (3) and the piston (4) jointly defining an upper chamber (5) and a lower chamber (6) each provided with at least one intake duct (7) and at least one delivery duct (8), and each duct including at least one valve (90, 91), and a linking rod (10) connecting the double-acting piston (4) to a transmission member (11) collaborating, on the one hand, with a guide roller (12) and, on the other hand, with a pinion (15), at least one anchoring member (22) collaborating with the pinion (15), a connecting rod (25) to which the pinion (15) is articulated by a pivot pin (26), the connecting rod (25) being connected to the crank (28) of a crankshaft (27) housed in bearings formed in the compressor casing (2).

Abstract: A linear actuator includes a cylinder main body. With respect to the cylinder main body, a slide table is disposed for reciprocal displacement through a guide mechanism, which is disposed on the cylinder main body. A stopper mechanism having a stopper bolt is disposed on one end of the slide table centrally in a widthwise direction perpendicular to the longitudinal direction of the slide table. In addition, when the slide table is displaced along the cylinder main body, an end of the stopper bolt comes into abutment with an end of a cover of the guide mechanism, whereupon the slide table becomes engaged therewith and movement of the slide table is stopped.

Abstract: A linear actuator includes a guide block constituting a guide mechanism. In the guide block, a pair of installation grooves are formed in a lower surface facing toward a cylinder main body. Ball circulation members having therein ball circulation holes are installed respectively in the installation grooves. Additionally, ball circulation passages through which balls circulate are provided. The ball circulation passages are made up from roll-reversing sections disposed on opposite ends of the ball circulation members, the ball circulation holes, second ball guide grooves formed in both side surfaces of the guide block, and first ball guide grooves of the slide table.

Abstract: In an acceleration and deceleration device which includes at least one energy storage device and a cylinder with at least one piston movably disposed in the cylinder and moved therein by a carrier element and a sliding door including a slidable door panel provided with an acceleration and deceleration device, a second carrier element is provided guiding either the first piston or the second piston for movement in the cylinder so as to control the movement of pistons and of the sliding door neat its end positions.

Abstract: An actuator control system has a dual concentric servo valve having a spool and at least one motor adapted to selectively displace the spool.

Abstract: Actuator arrangement, serving in particular to effect a deformation of an optical element, with a first, specifically fluidic-based actuator device (110.3), which is designed to exert on a body (108, 109.1) associated with the first actuator device (110.3) a first actuator force in an amount up a first maximum force value, wherein the arrangement includes a second, specifically fluidic-based actuator device (110.4), wherein the second actuator device (110.4) is designed to exert on the body (108, 109.1) associated with the first actuator device (110.3) a second actuator force in an amount up a second maximum force value, wherein further the second actuator device (110.4) is arranged in such a way in relation to the first actuator device (110.3) that the respective lines of action of the first actuator force and the second actuator force have at most a small distance from each other in the area of the their respective points of application on the body (108, 109.

Abstract: The present invention relates to a rotary motor, preferably a pivot drive for construction machinery, hoisting gear, trucks and the like, comprising an elongate, approximately tubular housing, at least one piston which is axially displaceably received in the housing and which can be axially driven by the charging of a pressure medium in a pressure chamber as well as at least one shaft which is received axially fixedly in the housing and rotatably around an axis of rotation, with the piston having a shaft passage cut-out by which the piston is axially displaceably seated on the shaft. In accordance with the invention, the shaft forms a crankshaft whose axis of rotation is offset with respect to the shaft passage cut-out.

Abstract: A compressed fluid motor has a plurality of cylinders with a piston and a piston rod. A main bearing is concentric with a crankpin and coupled to a shaft. Compressed fluid on the piston pushes on the main bearing via its corresponding piston rod. Bearing guide plates hold the one or more piston rod in place on the main bearing. A timing and control mechanism controls flow of compressible fluid to press on the piston and turn the shaft to perform work.

Abstract: A swivel motor has a plurality of work chambers and a join system between the work chambers that joins the work chambers at least by pairs. The arrangement of the joined work chambers is carried out in such a way that the work chambers which are connected to the first pressure medium connection alternate with those which are connected to the second pressure medium connection. At least two work chambers associated with different pressure medium connections are connected to a pressure compensation element, and the pressure compensation element is formed by a compensation space that is divided by a movable dividing element. A partial compensation space is connected in each instance to at least one work chamber of a pressure medium connection, and the dividing element is held in an initial position by oppositely acting springs. The spring force characteristic is formed by a spring arrangement which comprises a plurality of springs and has at least one coil spring and one elastomer spring.

Abstract: Each of two members to be fastened has a connecting surface, a communication groove opening on the connecting surface, and an engagement groove communicating with the communication groove and having an engagement surface parallel to the connecting surface. A fastening assembly has a connecting portion and two engaging pieces, each engaging piece having a fastening surface. The two members are placed with the connecting surfaces opposed, so that the engagement grooves are in communication each with the other through the communication grooves. The fastening assembly is inserted into the engagement grooves and the communication grooves, and the connecting portion is operated to draw together the two engaging pieces, causing the fastening surfaces of the engaging pieces to press upon the engagement surfaces of the engagement grooves, thereby clamping the two members together through their opposed connecting surfaces.

Abstract: A linear hydraulic motor (12) includes an elongate cylinder (26) and at least one piston (34) slidingly located inside the cylinder. The piston (34) has a longitudinally extending portion which fits with clearance in the cylinder and which describes a path in use which penetrates an interior zone of the cylinder which extends radially inwardly from an aperture in the cylinder wall. An internal reinforcing member (300) is slidingly located inside the cylinder to travel with the piston. The reinforcing member describes a path in use which also penetrates said interior zone of the cylinder which extends radially inwardly from the aperture in the cylinder wall and the reinforcing member has portions which are concentric and radially aligned with circumferentially spaced portions of the cylinder wall that are on opposite sides of said aperture in the cylinder wall.

Abstract: When different implements are attached to an agricultural tractor, various hydraulic actuators on the implement are operated by connection to the hydraulic system on the tractor. A single hydraulic fluid connector on the tractor has first and second ports with a separate valve assembly provided to control fluid of fluid to and from each port. This enables one doubling-acting hydraulic actuator to be connected to both connector ports so that the fluid flow to and from the actuator is controlled. For a different implement, one single-acting hydraulic actuator can be connected to one connector port and another single-acting hydraulic actuator can be connected to the other port of the same connector. Individual operation of the valve assembly for each port in this case allows independent control of the two single-acting hydraulic actuators.

Abstract: The invention relates to a valve 120, especially a check valve, for hydraulic plungers (3) of shield-type support frames in underground mining with a valve housing 121 and a switchable valve insert received therein, connections 126-129 for high pressure lines connected to the cylinder chamber and/or the annular space of the hydraulic cylinder 3, and at least one connection 30 for an additional unit such as a pressure relief valve, a pressure sensor, and/or a pressure display. The valve housing 121 can be mounted to the hydraulic cylinder 3, and in the mounting stage, the connections 125-129 on the valve housing 121 extend axially parallel to the axis of the hydraulic plunger 3. According to an advantageous further embodiment, the valve housing can be provided with at least one fastening means for an extension housing 40 that can be mounted in a releasable manner to at least one side wall 22B thereof for additional hydraulic functions of the shield-type support frame (see FIG. 2).

Abstract: A brake apply master cylinder includes a body and a piston assembly. The body includes a bore. The bore has a longitudinal axis, a closed front end, a primary fluid outlet fluidly connectable to a primary brake circuit, and a secondary fluid outlet fluidly connectable to a secondary brake circuit. The piston assembly includes a single brake apply piston positioned in the bore. The piston assembly fluidly divides the bore into a primary fluid chamber in fluid communication with the primary fluid outlet and a secondary fluid chamber in fluid communication with the secondary fluid outlet. Another brake apply master cylinder includes a body, a piston assembly, and a return spring assembly. The return spring assembly is positioned in the bore of the body and extends from the closed front end of the bore to a return-spring seat of a single brake apply piston of the piston assembly.

Abstract: A hydraulic system is provided. The hydraulic system includes a source of pressurized fluid, a first control valve, a first actuator, a second control valve, a second actuator, and a relief. The first control valve is coupled to the source of pressurized fluid. The first actuator is coupled to the first control valve and has a first end and a second end. The second control valve is coupled to the source of pressurized fluid. The second actuator is coupled to the second control valve and has a first end and a second end. The relief has an input and an output, with the input coupled to the first end of the second actuator and the output coupled to the second end of the second actuator and the second end of the first actuator.

Abstract: Improved actuators and valve control systems, and methods for controlling actuators and/or engine valves, are disclosed. In addition to the inherent capability of timing control, the ability to provide continuous valve lift or stroke control greatly improves engine achieve fuel economy, emission and performance. The power-off state of the actuator is at the minimum stroke, from which an easy start-up can be directly executed. The minimum stroke is also very beneficial to achieve efficient low load operation. Even with continuous lift variation, the present invention is able to keep the spring force neutral or zero point in the center of a stroke, thus maintaining an efficient scheme of energy conversion and recovery through the pendulum action. When in compression braking or other high engine cylinder air pressure working mode, the invention is able to supply necessary force to open the engine valve.

Abstract: A hydraulic system is provided. The hydraulic system includes a source of pressurized fluid, a first control valve, a first actuator, a second control valve, a second actuator, and a relief. The first control valve is coupled to the source of pressurized fluid. The first actuator is coupled to the first control valve and has a first end and a second end. The second control valve is coupled to the source of pressurized fluid. The second actuator is coupled to the second control valve and has a first end and a second end. The relief has an input and an output, with the input coupled to the first end of the second actuator and the output coupled to the second end of the second actuator and the second end of the first actuator.

Abstract: Improved actuators and valve control systems, and methods for controlling actuators and/or engine valves, are disclosed. In addition to the inherent capability of timing control, the ability to provide continuous valve lift or stroke control greatly improves engine achieve fuel economy, emission and performance. The power-off state of the actuator is at the minimum stroke, from which an easy start-up can be directly executed. The minimum stroke is also very beneficial to achieve efficient low load operation. Even with continuous lift variation, the present invention is able to keep the spring force neutral or zero point in the center of a stroke, thus maintaining an efficient scheme of energy conversion and recovery through the pendulum action. When in compression braking or other high engine cylinder air pressure working mode, the invention is able to supply necessary force to open the engine valve.

Abstract: A blade holder for cutting machines includes a blade head held on a raising and lowering device and an adjustment mechanism for a circular blade that is held on the blade head. The adjustment mechanism, for the movement of the circular blade between a cutting position and a ready position, is provided with an adjustment piston rod having an adjustment piston that is guided in a chamber of the blade head housing and can be moved by compressed air. The adjustment piston rod is biased by a compression spring into the ready position of the circular blade. The piston surface of the adjustment piston has a cross-sectional area that is configured such that as the path of the adjustment piston in the direction of adjustment increases, the piston surface that is acted upon by compressed air increases.

Abstract: Improved actuators and valve control systems, and methods for controlling actuators and/or engine valves, are disclosed. In addition to the inherent capability of timing control, the ability to provide continuous valve lift or stroke control greatly improves engine achieve fuel economy, emission and performance. The power-off state of the actuator is at the minimum stroke, from which an easy start-up can be directly executed. The minimum stroke is also very beneficial to achieve efficient low load operation. Even with continuous lift variation, the present invention is able to keep the spring force neutral or zero point in the center of a stroke, thus maintaining an efficient scheme of energy conversion and recovery through the pendulum action. When in compression braking or other high engine cylinder air pressure working mode, the invention is able to supply necessary force to open the engine valve.

Abstract: A load handling machine includes a body, a lifting arm pivotally mounted to the body about a first pivot axis, and a load handling implement pivotally mounted to the lifting arm about a second pivot axis. A first actuator provides movement about the first axis, and a second actuator provides movement about the second axis. A displacement device is mounted on the body and the lifting and includes a pair of cylinders. The second actuator and the displacement device are interconnected such that as the lifting arm is lowered, fluid ejected from one of the pair of cylinders of the displacement device is fed to an annulus side of the second actuator, and as the lifting arm is raised, fluid is ejected from annulus sides of both of the cylinders of the displacement device and is fed to a non-annulus side of the second actuator.

Abstract: A two-cycle hot-gas engine comprising an expansion piston in a heatable cylinder member and a compression piston in a coolable cylinder member. The expansion piston and the compression piston are disposed along a common axis.

Abstract: The linear actuator comprises two variable-volume chambers (5) containing an operative liquid, each of the chambers (5) being delimited on one side by one of two mobile elements (4), which mobile elements (4) are solidly constrained one to another. One of the mobile elements (4) is connectable to an external user, for example a gearwheel of a gear coupling. A geared rotary positive displacement pump (10) reversibly transfers the operating liquid from one chamber (5) to the other chamber (5) through an infeed conduit (6), to move the mobile elements (5) selectively in one direction or another. A recycling conduit (7), narrower than the infeed conduit (6), places the two chambers (5) in communication and realizes a closed circuit, in a situation where the mobile elements 4) are stationary and the pump (10) is active.

Abstract: The invention is a bi-fluid actuator for precise bi-directional movement and positioning of a mechanical object or load. The bi-fluid actuator includes a pneumatic fluid container defining opposed first and second pneumatic fluid chambers, and having a first mechanical object secured between the chambers; a hydraulic fluid container defining opposed first and second hydraulic fluid chambers, and having a second mechanical object secured between the first and second hydraulic chambers; a pneumatic fluid controller; and, a hydraulic fluid controller. Directing pneumatic fluid into either the first or second pneumatic chambers, while controlling flow of hydraulic fluid between the first and second hydraulic chambers, controls movement and positioning of the mechanical objects which may be secured to a load.

Abstract: A hydraulic actuating unit for integration into a preassembled folding roof unit of a motor vehicle is adapted for mounting as a single unit in a motor vehicle with the hydraulic actuating unit integrated therein. The preassembled folding roof unit has a folding roof with a foldable cover and a framework for the cover. A main bow is pivoted by a hydraulic main bow actuator and a rear bow is pivoted by a hydraulic rear bow actuator, each actuator being of the double-acting type. The hydraulic actuating unit also has an actuable two-position control valve, which control valve has an outlet port, an inlet port and a reservoir port, the outlet port being connected to a working chamber of the main bow actuator and/or a working chamber of the rear bow actuator. The control valve, in a first position, connects the associated outlet port to the reservoir port and, in a second position, connects the associated outlet port to the inlet port of the control valve.

Abstract: In an apparatus and method for actuating arms used on a borehole data-logging tool to deploy measuring instruments against a borehole wall, a mandrel is provided. At least one arm carried by the mandrel is mounted to the mandrel to move between an expanded position, in which a part of the arm projects from the mandrel, and a retracted position. A resilient biassing compression spring provides a resilient biassing force on each arm for biassing the arm towards its expanded position. A hydraulic piston and cylinder assembly associated with each arm restrains the arm against movement towards its expanded position. A drive piston and cylinder assembly acts upon the resilient biassing compression springs for adjusting the resilient biassing force acting upon each arm.

Abstract: A fluid power interlock system and method for providing same including a circuit having a first valve shiftable between a first and second state having an input and a pair of selectively operable first outputs. One of the first outputs is operatively connectable to a first actuator and the other of the first outputs is operatively connected to a second valve shiftable between a first and second state. The second valve has a pair of selectively operable outputs, one of the second valve outputs is operatively connectable to a second actuator, and the other of the second valve outputs is operatively connected to the first valve and provides a pilot signal thereto for permitting the first valve to shift from a first state to a second state. Shifting state of either of the first and second valves interrupts the pilot signal thereby preventing the non actuated valve from being actuated and shifting state. The system may also include a manifold, wherein the first and second valves are secured to the manifold.

Abstract: A pressurized-fluid-operated actuator has two piston surfaces for providing increased output force. The actuator includes a hollow piston that is divided into two inner chambers by a stationary inner dividing wall that is rigidly connected with a cylinder end wall. The piston has an outer diameter that is smaller than the inner diameter of the cylinder, and the piston carries three axially spaced sealing rings that define two axially-spaced annular chambers between the piston and the cylinder. Each of the annular chambers is in fluid communication with a respective port provided in the cylinder wall. Introduction of pressurized fluid into one port causes the fluid pressure to act on a single piston surface to retract the piston and rod, and introduction of pressurized fluid into the other port causes the fluid pressure to act on two axially-spaced piston surfaces to provide an increased output force without increasing the diameter of the cylinder and piston and without increasing the pressure of the fluid.

Abstract: The present invention relates to a turning device for providing a rotational movement in a work machine so as to turn the work machine (8) quickly and smoothly. The turning device comprises a frame (1) in which is arranged at least one control rim (4) turning about the axis of rotation (6). To the control rim is arranged a swiveling axle (5) that projects substantially perpendicularly from the control rim, two pressure-medium-operated actuators (9, 10) at an angle with respect to one another are in turn arranged in the swiveling axle for turning the control rim about the axis of rotation. The actuators are double-acting actuators, whereby independent shuttle valves (28, 29) in the pressure line pairs (24, 25, 26, 27) applied to the actuator are arranged to regulate the pressure medium flow controlling the operation of the actuators.

Abstract: A valve system is provided for the hydraulic work system of a work vehicle, in particular of an industrial truck, with a elevating drive system for raising and lowering a load and a tilting drive system, each of which can be actuated by a control valve, in particular by an electrically actuated control valve, the opening width of which determines the speed of movement of the user. The elevating drive system is realized in the form of a single-action hydraulic cylinder and a check valve in the form of a seat valve that can be opened toward the hydraulic cylinder is located in a hydraulic line leading from the control valve to the hydraulic cylinder. The tilting drive system is realized in the form of a double-action hydraulic cylinder. The valve system has an improved function with low energy losses. The check valve has a control surface that acts in the direction of the opening position and can be pressurized by the load pressure of the elevating drive system.

Abstract: A hydraulic actuator comprised of a toroidal piston within a toroidal enclosure, with differential fluid pressure alternatively applied to upper and lower surfaces of the piston to cause a reciprocating motion, and with plural double ended piston rods extending in parallel above and below the piston, and slidably extending in fluid sealed relation through end caps of the toroidal enclosure to distribute the vibrational force produced by the reciprocating piston over plural points of a surface area of the mass to be vibrated, thereby reducing the likelihood of stress, strain, or harmonics in the mass.

Abstract: A removable side shifter attachment attachable to the carriage bar of a lift truck has a frame shiftable with respect to the truck. The frame includes a shifter carriage bar for receiving a lift fork. A hydraulic cylinder attached to the truck carriage bar having rods contacting the frame at its sides is positioned horizontally forwardly of the truck carriage bar and between the truck carriage bar and the shifter carriage bar. The cylinder is positioned generally within a J-shaped portion of the shifter carriage bar so that the cylinder does not extend substantially above or below the carriage bar and does not appreciable add to the overall thickness of the apparatus. The cylinder further includes two axially aligned chambers separated by a central partition, each chamber containing a piston in contact with a respective rod, each piston dividing its respective chamber into interior and exterior portions.

Abstract: A method and apparatus for providing control of multiple actuators with a single control lever is provided. The method and apparatus is adapted for use in an electro-hydraulic system having a microprocessor, multiple actuators, respective electro-hydraulic directional control valves for each actuator, and individual control levers operatively associated with the microprocessor for controlling movement of the respective electro-hydraulic directional control valves. The method and apparatus is accomplished by providing a switch on each of the control levers that is operational to condition the microprocessor to direct simultaneous signals to the respective electro-hydraulic directional control valves to control each of the multiple actuators in proportion to the degree of movement of the one actuator when the switch thereon is depressed.

Abstract: A multi-stage hydraulic ram assembly for the accumulator drive system of an elevator assembly includes a plurality of piston-cylinder arrangements connected hydraulically in parallel and mechanically in series. The piston-cylinder arrangements are disposed in substantial side-by-side relationship, constituting adjacent or successive stages of the ram assembly. A bracket is fixed to one of the cylinders and is slidably connected to the adjacent cylinder, for interconnecting adjacent cylinders of the piston-cylinder arrangements, and a drive system is provided for operating the ram assembly. Steps are taken to control the direction and speed of movement of adjacent stages of the assembly, and to ensure that all of the stages of the assembly move at substantially the same speed.