Abstract: A housing structure for a hydrostatic machine comprising two shells of part-cylindrical form. The shells are connectable together at their junction surfaces on a parting-plane. A drive-shaft is supported in the housing structure and its axis of rotation lies on the parting-plane, this being the axis of symmetry of the shells. The shells are identical in cast shape, and have symmetrically arranged recesses and surface features to either side of said axis of symmetry. In the interior chamber between the shells, working component elements of the machine are located and driven by the drive-shaft to convert mechanical power into hydraulic power passing through openings or fluid-passageways provided in the housing structure.

Abstract: A radial piston hydrostatic machine having an outer housing structure and defining an internal chamber, a drive-shaft supported in the housing and operatively connected to the cylinder-barrel, the cylinder-barrel having a number of radial cylinders, each cylinder containing a piston such that the pistons bear on the track-ring, the track-ring eccentrically position within the internal chamber by means of fixed abutment means in the housing, the abutment means disposed radially adjacent the track-ring for resisting the action of the pistons on the track-ring and thereby suppressing vibration emanating from the track-ring.

Abstract: Rotary actuator (1) including a housing (2), which defines a working chamber (3) with at least partially circular section for actuation with a pressure fluid, a pivoting piston (5) which is sealingly arranged against the inner wall of and pivotable between two end positions in said working chamber, said housing being divided through the working chamber perpendicular to its symmetry axis.

Abstract: In a rotary hydraulic actuator wherein a hermetic casing has the inside divided into a first hydraulic chamber and a second hydraulic chamber by a vane slidably rotatable on an inner curved wall of the casing, the vane is rotatable by an oil pressure supplied to the respective chambers, and the movement of the vane is taken out from an output shaft, the inner wall of the casing which is in sliding contact with the vane is formed with a polytetrafluoroethylene sliding member.

Abstract: A hydraulic actuator is provided with a housing with an oil compartment formed therein; a power output shaft rotatably supported on the housing and extending out from an interior of the oil compartment to an exterior of the housing; a vane radially extending out from the power output shaft and maintained in contact with an inner wall of the oil compartment, whereby the vane divides the oil compartment into a first oil compartment and a second oil compartment; a first hydraulic pressure passage communicating the first oil compartment and a hydraulic pressure source with each other; a second hydraulic pressure passage communicating the second oil compartment and the hydraulic pressure source with each other; and an oil control valve regulating at least one of a first hydraulic pressure to be supplied to the first oil compartment through the first hydraulic pressure passage and a second hydraulic pressure to be supplied to the second oil compartment through the second hydraulic pressure passage.

Abstract: A fluid operated rotary drive, which possesses a drive means having an output drive shaft able to be driven for oscillating motion. On one axial side of the drive means a position detection means is arranged, which possesses an actuating member connected with the output drive shaft and which on rotary motion of the output drive shaft performs an oscillating movement about a pivot axis. The actuating member cooperates with sensors, which may be set on holders. Each holder is arranged on its own setting ring, such setting rings being arranged coaxially in relation to each other with the holders extending away from the drive means. The setting rings are able to be turned in relation to one another and furthermore in relation to the housing for setting the positions to be detected and may be fixed in the settings made.

Abstract: A rotary actuator (1) comprising a housing (2), which defines a working chamber (3) for actuation with a pressure fluid and having at least partially circular section, a pivoting piston (5) which is arranged sealingly against the inner wall (4) of and rotatable between two end positions in the working chamber, is featured in that the pivoting piston (5) itself is pivotally supported in bearings (16) which are arranged in the housing (2) axially at each side of the working chamber (3), and wherein it comprises means for cooperation with an external rotary shaft, whereby the housing (2) on at least one of its end walls is adapted so as to be contacted against and be fixedly fastened to a corresponding end wall portions of a second rotary actuator housing (2), and whereby these housings are fixable to one another in such a way that the axes (X) of the pivoting pistons of the respective housings are coaxial and that the pivoting pistons thereby are capable of affecting one common outgoing shaft.

Abstract: In a hydraulic transaxle, a radial ball piston pump and motor combination receive input torque and translate it into output torque, the direction of which is determined by the position of a cam ring located in the transaxle housing. This cam ring is movable by means of a control shaft which is manually operated. The invention provides an extended control pin linking the control shaft to the cam ring and a channel formed in the transaxle housing. When the control shaft nears a neutral center position, the channel and its rounded edges provide a detented ramp into which the length of a portion of the control pin may be seated. A spring acting on the control shaft urges the control pin into the detented position.

Abstract: In a pressure medium operable cylinder/piston unit for the provision of at least one rotary movement, comprising a cylinder bore (8) having inside it a radially internally projecting partition wall (4) and a vane piston (5) which projects radially outwardly from a piston rod (3) extending through the cylinder housing (2) and forms two alternately pressurisable radial pressure chambers (26 and 27), the radial partition wall (4) and the radial vane piston (5) are arranged on the piston rod (3) adjacent an axial piston (6) which, together with the cylinder bore (8), forms outer pressure chamber (14), and the radial partition wall (4) is arranged in the cylinder (2) so that, by way of a projection (18), it is secured against rotation.

Abstract: An adjustable rotor and/or a radial piston machine which may utilize an adjustable rotor. The rotor has a primary eccentric rotatable around an axis and a secondary eccentric adjustable in position relative to the primary eccentric. The radial piston machine includes a plurality of piston cartridges arranged radially around the axis and both high pressure and low pressure fluid distribution systems. Multiple units may be axially coupled. A single unit may handle a variety of fluids in various combinations.

Abstract: A hydrostatic radial piston engine with two rotors that are supported on an axle so that they can rotate easily thereon. The rotors have a plurality of radial bores with displacement elements (pistons with slide ring) therein, sliding on the inside of a piston ring. The bores are connected via control slits with transport channels (high-pressure/low-pressure) that open on a side on the rotors for the purpose of controlling the transport of the pressure medium. The two rotors can be rotated easily on the axle which mounted on an intermediate bottom. The intermediate bottom is disposed between the rotors. Check plates are disposed on the ends of the axle which take up the axial forces produced by the pressure medium in the control slits of the rotors. The piston rings are supported in the intermediate bottom by a common connecting shaft.

Abstract: An adjustable rotor and/or a radial piston machine which may utilize an adjustable rotor. The rotor has a primary eccentric rotatable with a shaft and a secondary eccentric adjustable in position relative to the primary eccentric. The radial piston machine includes a plurality of piston cartridges arranged radially around the shaft and both high pressure and low pressure fluid distribution systems. Multiple units may be axially coupled. A single unit may handle a variety of fluids in various combinations.

Abstract: Rotary actuator, including a cylinder and motor shaft, as well as end caps which define a work chamber, whereby a number of ribs on the inside surface of the cylinder and the same number of vanes on the motor shaft divide the working area into work chambers which are alternately supplied with hydraulic medium, and seal units inside grooves in the ribs and vanes which hydraulically separate the work chambers from one another, characterized by the fact that there is a space between the seals and the side walls of the grooves which is offset by an additional volume.

Abstract: A hydromechanical transmission which includes a swash-plate type hydrostatic axial piston motor with a rotary cylindrical drum having work cylinders and a driven shaft. A planetary gear is located adjacent to and coaxial with the piston motor and includes a rotary hub surrounding both the planetary gear and the axial piston motor, A ring gear is located at the inner surface of the rotary hub and a stationary hub support having an open ended cavity to hold the axial piston motor is mounted within and coaxial with the rotary hub. The end wall of the cavity is a control surface for the axial piston motor and pressure medium channels which open on the control surface for periodic connection with the work cylinders in the cylindrical drum are formed in the stationary hub support.

Abstract: An hydraulically powered rotary actuator for rotating a first portion of a work machine relative to a second portion of the work machine has inner and outer rings enclosed by first and second cover plates. The inner and outer rings are spaced apart to define an hydraulic power chamber to which pressurized fluid is supplied to rotate one of the inner or outer rings. The first portion of the work machine is connected to the rotatable ring and rotates with it. A large diameter bearing assembly rotatably supports the rotatable ring and the first portion of the work machine. Most prior work machines with rotatable car or upper structure require large expensive components including gear reduction assemblies, an hydraulic motor, and large diameter swing gear. The subject actuator simplifies the construction by eliminating many of the prior components.

Abstract: An hydraulically powered rotary actuator for rotating a first portion of a work machine relative to a second portion of the work machine has inner and outer rings enclosed by first and second cover plates. The inner and outer rings are spaced apart to define an hydraulic power chamber to which pressurized fluid is supplied to rotate one of the inner or outer rings. The first portion of the work machine is connected to the rotatable ring and rotates with it. A large diameter bearing assembly rotatably supports the rotatable ring and the first portion of the work machine. Most prior work machines with rotatable car or upper structure require large expensive components including gear reduction assemblies, an hydraulic motor, and large diameter swing gear. The subject actuator simplifies the construction by eliminating many of the prior components.

Abstract: A slipper guide for use in radial piston type hydraulic pumps and motors, especially those utilized in hydrostatic transmissions. The slipper guide provides an annular path for the slippers, guiding and maintaining the slippers engaged with the inner circumferential surface of the track ring as the slippers are rotated within the track ring by the cylinder. The slipper guide consists of two plates axially attached to the track ring and fixed relative thereto. Each plate includes an annular, axially inwardly extending projection forming an annular surface upon which an under surface of an outer portion of the slippers rests. The annular projection positions and maintains the top surface of the slippers against the inner circumferential surface of the track ring.

Abstract: A hydrostatic displacement machine has in a revolving cylinder block several displacement elements movable in a guideway and having a radial position during the rotation of the cylinder block determined by a nonrotating displacement ring. The displacement elements, viewed axially, are retained on the displacement ring by two retaining rings. The retaining rings feature relative to the displacement ring a radial seal. The axial seal of the retaining rings is effected in standstill, relative to the housing or housing lid, by way of spring elements, and during the pumping operation, by a contact force which is indirectly dependent on the operating pressure.

Abstract: A variable-stroke crank mechanism has a crankshaft rotatably supported in a casing for relative rotation about an axis with a crankpin displaced out of alignment with the axis. An eccentric collar is rotatably mounted on the crankpin for revolving around the axis in response to the relative rotation of the crankshaft with respect to the casing to reciprocally move an actuator relative to the casing. A stroke adjusting mechanism for adjusting angular displacement of the eccentric collar on the crankpin comprises an internal ring gear integral with the eccentric collar concentrically with the crankpin, a planetary pinion rotatably mounted on the crankshaft and meshing with the internal ring gear, a sun gear meshing with the planetary pinion, and a stroke adjusting shaft rotatably disposed axially in a portion of the crankshaft and coupled to the sun gear, whereby the stroke adjusting shaft is adjustable in angular displacement to adjust a stroke of reciprocating movement of the actuator.

Abstract: The present invention is directed to a hydro-mechanical or electro-hydro-mechanical control system utilized for positioning a mechanical device. The control system incorporates a control valve for selectively controlling the flow of hydraulic fluid to input ports of a power output transducer in response to a mechanically applied input signal. The power output transducer is then utilized to position a mechanical device. The control system is a closed loop circuit adapted to supply hydraulic fluid at a desired supply pressure to the control valve. The supply pressure is varied in relation to the absolute value of the pressure differential or load pressure exerted across the input ports of the power output transducer. A pressure regulating apparatus is provided for selectively regulating the supply pressure to a value that is nominally equal to the absolute value of the load pressure summed with a preselected supplemental pressure value across the regulating apparatus.

Abstract: A piston pump is constructed so that the displacer or piston working strokes occur in sequence with varying phase differences which have a non-integral ratio to one another. Thereby, the risk of excitation of noise or resonance vibrations is greatly reduced.

Abstract: A variable displacement radial ball pump (11) is disclosed of the type in which the balls (59) are restrained by a cam ring (25), which is pivotable about a cam pivot pin (27) to vary the displacement of the pump. In accordance with the invention, in order to return the pump to absolute zero displacement, the pump is provided with a detent mechanism (65;83). The cam ring 25 has a neutral region (73) and a ramp surface (77), and a detent member (69;89) is biased into engagement with the neutral region when the cam ring is in neutral (FIGS. 2 and 3). When the cam ring is displaced from neutral, the detent member engages the ramp surface, against the bias force of a spring (71;91), which exerts a force tending to return the cam ring to neutral in the absence of an input to the control assembly (33).

Abstract: A control system for a variable displacement hydraulic pump with a two-lever type of feedback lever mechanism. The control system comprises a pressure responding ram for causing, upon receiving pump output pressure or outside pilot pressure, a servo spool of a servo valve to be displaced, the servo valve for causing a larger chamber of a servo cylinder to be selectively supplied with the pump output pressure, the servo cylinder for controlling angle of inclination of a swash plate of the pump in order to control the pump output flow rate, a two-lever type of feedback lever mechanism for linking the pressure responding ram, the servo spool of the servo valve and the servo piston of the servo cylinder to each other.

Abstract: An articulated mechanism for use as an articulated arm of an industrial robot, for example, includes a plurality of arms interconnecting articulations having respective fluid pressure angular displacement motors for angularly displacing the arms relatively to each other. The motors have sidewalls forming working chambers, where an inner surface of the sidewall is exposed to working fluid pressure tending to bow the sidewall outward, and an outer surface of the sidewall has a plurality of counteracting pressure chambers which apply a counteracting pressure force against the sidewall to oppose the outward bowing force, the counteracting pressure force increasing in pressure surface area as the piston is displaced within the motor chamber.

Abstract: An integrated drive arrangement for a vehicle propulsion system for transmitting vehicle drive torque and for independently driving external implements. The drive arrangement includes a power input shaft having a number of axially spaced drive gears and being driven by a prime mover. The pump shaft of a variable displacement pump is drivingly connected with one of the drive gears of the power input shaft. A fixed displacement motor is connected in closed circuit to the variable displacement pump. A number of drive pinions are spaced axially along an intermediate shaft which is spaced from the power input shaft and are connected to the intermediate shaft and the power input shaft by an electromagnetic clutch. First and second power take-off shafts are drivingly connected with the intermediate shaft such that the power input shaft imparts independent rotation to the power take-off shafts and the pump shaft.

Abstract: A hydraulic power system having first and second hydraulic power converters in which the speed of the second power converter is proportional to the speed of the first power converter. The first hydraulic power converter includes a plurality of hydraulic power producing elements. At least one of the power producing elements provides power for power driving, and at least one of the power producing elements pumps hydraulic fluid. The hydraulic fluid is connected to and drives the second hydraulic power converter at a speed proportional to the speed of the first power converter.

Abstract: A neutral centering spring mechanism (71) is provided for a variable displacement hydrostatic pump (25) of the type of which control of the displacement occurs in response to rotation of a control shaft (101;101'). Disposed about the control shaft is a pair of preferably identical actuator members (111,113), each of which is in engagement with a pin (115) such that clockwise rotation of the control shaft rotates one actuator member (111) while counter-clockwise rotation of the control shaft rotates the other actuator member (113). Each actuator member defines a movable stop surface (131,137), which are in engagement with fixed stop surfaces (133,139). A single torsion spring member (121) surrounds the actuator members, biasing both actuator members toward the neutral position.

Abstract: The improved hydrodynamic variator of velocity comprises a pump (3) having radial pistons and a hydromotor (4) also having radial pistons. At least the pump is arranged with a variable eccentricity and there is provided a central body (56) the latter having frontal distributors (30 and 31) which are placed in communication with the radial cylindrical cavities respectively of the pump and the hydromotor by means of the openings of the conduits (32 and 33). By varying the eccentricity of the pump, the rate of flow of the liquid in the pump is varied, thus causing a variation in the number of turns of the hydromotor.

Abstract: An arrangement for a compressor with oscillating piston wings has a series of mutually angularly displaced discharge slots arranged in a radially extending end wall between a working chamber of the machine and an oppositely disposed discharge chamber. The discharge slots are covered over by valve members of resilient nature. The valve members may be inserted in the end wall with an end groove in a recessed manner to engage a valve seat about each slot.

Abstract: A drive comprising a first group of cylinders of a radial hydraulic pump, rotating in relation to the drive frame about a first axis, and torsionally integral with the input shaft of the drive and with a housing inside which the first group of cylinders rotates; a second group of cylinders of a radial hydraulic motor, rotating in relation to the frame about a second axis; an output shaft, the axis of which is located between the aforementioned axes, and which is integral with a gear meshing with a gear integral with the housing in which the first group of cylinders rotates, and with another gear integral with the second group of cylinders; a mechanism for varying displacement of the first and second group of cylinders; and a distributing mechanism for alternately connecting the cylinders in the first group with those of the second group.

Abstract: An internal combustion engine (20) which includes an oscillating piston (52) and rotary valves (34) and (36) is shown. Oscillating movement of piston shaft (50) is transmitted to oscillating idler shaft (66). Outer and inner coaxial shafts (82) and (84) are connected by direction reversing gears (88) for counterrotation of the shafts. Outer shaft (82) is connected to oscillating shaft 66 through gear sets (102) and (104), and inner shaft (84) is connected thereto through gear sets (106) and (108). Gear sets (102) and (106) include one-way overrunning clutches (110) and (112), and gear sets (104) and (108) include electromagnetically controlled friction clutches. (See FIG. 1) In FIG. 13, mechanically operated clutches (200A) and (200B) are used in place of the electromagnetically controlled friction clutches shown in FIG. 1, and in FIG. 17, sector gear sets (244) and (246) connect oscillating shaft 66 to respective coaxial shafts (82) and (84).

Abstract: A rotary-type fluid energy convertor comprises a pair of cylindrical body members, a pintle inserted into the cylindrical body members and having a cylindrical central portion between the body members, a cylinder barrel mounted on an outer periphery surface of the central portion of the pintle, the cylinder barrel being provided with a plurality of spaces isometrically arranged in radial directions thereof, a plurality of bushings fitted into the spaces, a rotary body mounted to the body members to be rotatable and having an inner periphery sectioned into a plurality of flat surface portions against which the top flat portions of the bushings closely abut, respectively, so as to form pressure chambers therebetween, and high and low pressure side fluid passages formed between the cylinder barrel and the cylindrical portion of the pintle.

Abstract: The present invention relates to a fluid operated device having a stator and a rotating vane mounted on a shaft enclosed in a cylindrical body with head members at each end of the housing. The pressure of the fluid is different on each side of the vane for such devices, and an elastomeric seal is provided on the vane to prevent leakage of fluid from one side of the vane to the other. The present invention provides for a metal to metal seal between the cylindrical body and the head members such that the elastomeric seal on the vane will seal against metal surfaces as it sweeps along the union of these two members.

Abstract: A fluid-operated actuator (2) is connected to a pumping unit (12) through a control unit (10) in which are mounted control valves (30,32) for regulating the movements of the actuator. The control valves communicate with the actuator and the pumping unit through conduits in replaceable adaptor plates (60a,60b,60c). By changing the adaptor plates, different operating modes of the actuator can be selected. The pumping unit is carried on the control unit through a rotationally adjustable connection to permit it to be mounted upright although the orientation of the actuator and control unit may vary.

Abstract: A rotor assembly includes a shaft and a planar vane extending in a radial direction from the shaft and having a peripheral groove receiving a resilient sealing gasket. The vane includes a tongue portion which depends into a radial cavity in the shaft and is sealably cemented thereto. Radially extending ribs on the ends of the tongue are accurately fitted against the ends of the cavity which are aligned with the adjacent ends of the bottom walls of the peripheral groove.

Abstract: A damping device, in particular for operating members within motor vehicles comprises a housing including a chamber, a liquid phase medium within the chamber, a shaft extending through the chamber, at least one radial vane attached to the shaft in such a manner that when pivoting the vane in the direction of one of two circumferentially spaced radial stops, the medium displaced out of one chamber portion will flow into the other chamber portion through means of a flow constriction, either the housing or the shaft being stationary and the housing or the shaft being connected with the actuating member, whereby at least one throughbore is defined within the vane and serves as the flow constriction.

Abstract: A one moving part, bi-directional rotary displacement mechanism for conveying rotational movement about an axis to movable members in flight vehicles. In consists of an enclosure having bi-directional rotation capability, encapsulating a vane with bi-directional ducts venting from its load bearing surfaces. The vane is affixed to a bi-directionally ducted shaft, having bi-direcitonal rotation capability, extending through the center and outside of the enclosure. A conically shaped, sealed, positive stop, with load bearing surfaces, eminating from the inside radius of the housing, points toward the horizontal axis, supports the shaft and facilitates axial rotation. The vane has a radius concentric with the inside radius of the enclosure and allows sealed bi-directional rotary movement between the two surfaces. Two sealed cavities exist between the load bearing surfaces of the vane and the positive stop. Pressure to and from the cavities flows through the joined vane and shaft ducting.

Abstract: Each of the head assemblies of a rotary actuator includes a tapered roller bearing in which the shaft of the actuator is journaled and an end plate against the inner face of which the stator and movable vanes of the actuator are sealed by a resilient jacket. A pressure equalizing passageway extends through each end plate from the cavity in which the associated roller bearing is mounted to the gasket which seals the stator to the end plate, thereby to equalize the pressure across the end plate and reduce the torque required to initially rotate the actuator shaft.

Abstract: A rotary actuator having a housing defining an opening, an output shaft extending through the opening, a stator vane and rotor vane associated with the output shaft and opening to define a plurality of actuation chambers and an inner surface of the housing extending inwardly past a shoulder portion of the output shaft to seal directly against the shaft.

Abstract: A piston machine, particularly a radial piston machine which includes a pintle supporting a rotor which has a plurality of radially extending bores in which radial pistons are guided. These bores are in communication with control chambers formed in the pintle. One of the chambers is a high-pressure chamber and the other is a low-pressure chamber. Pre-control grooves and additional passages are provided at the control chambers to prevent, during the operation of the radial piston machine the occurrence of pressure shocks at the inner and outer dead centers.

Abstract: This invention relates to a radial piston device with a rotatable casing useful as a pump or a motor. The device is highly efficient with an overall efficiency of 0.95 and a mechanical efficiency of 0.97, a wide rotational speed range of over 1000 rpm, and can be made with continuously variable or fixed displacement. The device is compact in size, light in weight and simple in structure making it easy to manufacture. Moreover, the device can be constructed from a variety of materials without restrictive material requirements, can operate with both filtered and non-filtered oil, and is not sensitive to environmental effects. When the device is mounted on a wheel to form a hydrostatic transmission system, the layout and performance of the vehicle are significantly improved. The displacement control means provided by the present invention is also applicable to other motors or pumps with eccentric shafts. This invention also provides a simple and reliable flat oil seal.

Abstract: The hydraulic actuator (35) utilizes the centrifugal head developed in its pressure chambers (52,54) when the housing (44) rotates as a source of pressure. As actuator (35) rotates fluid exits outlet port (56) and passs through a servovalve (64) into chamber (54) to move vane (49) relative to the actuator (35). To move vane (49) in the other direction, fluid exits outlet port (58) and passes through the valve into chamber (52). This self-powered actuator has utility in systems requiring relative angular positioning between a pair of rotating elements such as a pair of voltage regulator rotors in a dual permanent magnet generator.

Abstract: The invention relates to a hydropneumatic spring suspension or shock absorber device, in particular for heavy motor vehicles, which a spring element comprising a housing for a spring bellows filled with a hydraulic medium which is in flow connection with a chamber filled with hydraulic fluid and in which a pneumatic spring is disposed which is deformable under hydraulic pressure, one end of the bellows being supported in the housing and medium being admitted at the other end via an abutment connected with one of the parts. In accordance with the invention, a compact low wear-and-tear spring suspension device is obtained in that the bellows is bent into a substantially circular arc shape and the abutment is movable along the circular arc.

Abstract: This is a fluid-operated linear-rotary robot-like actuator reconstructed from a standard fluid cylinder device. The solid piston of the standard cylinder device is replaced with a self-contained vane-operated piston structure formed of spaced piston parts and an interposed vane chamber and in which a vane-operated work piston is rotated. The work piston extends through the forward cylinder head. A second piston rod extends from the rear part of the piston structure through the rear cylinder head and has passages for supplying the vane chamber of the piston with fluid under pressure. Suitable push button and microprocessor control systems, either by push button or automatically, are provided for controlling the operation of the actuator to give combined linear and rotary movement to a robot hand.

Abstract: A variable capacity radial piston pump is disclosed, in which the radially outer ends of the pistons are constrained by engagement with the radially inner surface of a cam ring assembly that includes a radially inner ring, a radially outer ring, and rollable bearings between the inner and outer rings. The cam ring is shiftably mounted in the pump housing so that its magnitude of eccentricity relative to the pump rotor can be varied in order to vary the magnitude of suction and compression forces generated in the working fluid in the rotor chambers associated with the respective pistons. Several mechanisms for affecting the cam ring/rotor eccentricity variation are shown and described.

Abstract: A hydraulic radial piston machine for stepplessly displaceable piston stroke has a plurality of pistons which are formed as roller bodies and abut linearly with their circular spherical regions against a control curve which is formed on a control ring displaceable relative to a cylinder body of the machine, wherein the control curve is formed as a symmetrical spatial curve such that the curve regions which form both the inner dead point for the pistons and the outer dead point for the pistons change in the displacement direction of the control ring.

Abstract: A variable displacement fluid pump comprises a rotor rotatably disposed within a housing, an eccentric ring movable close to and apart from the rotor to change a first eccentricity between a center of an inner periphery of the eccentric ring and a fixed center of rotation of the rotor so as to vary a displacement of the pump, and a plurality of pumping chambers each having a variable volume which changes sequentially to introduce thereinto fluid from an inlet port and to discharge therefrom fluid to a discharge port as the motor rotates. The rotor is so disposed that the fixed center of rotation of the rotor is spaced apart by a predetermined second eccentricity from a locus of the center of the inner periphery of the eccentric ring towards the discharge port.

Abstract: A hydraulic pivot drive comprising a rotary-piston hydraulic cylinder and control device for maintaining the pressure difference between pressure chambers defined by the rotary vane and at least one radial wall of the cylinder housing required for maintaining a defined relative rotary position between the vane and the housing of the rotary piston hydraulic cylinder. The control a follow-up control valve, wherein the actual condition relative to the pivot angle is fed back via a measuring spindle coupled with the rotating part of the rotary piston hydraulic cylinder and the desired value is pre-set by rotation of a spindle nut engaging the spindle, an actuating member arranged for axial displacement together with the spindle nut and for actuating pairs of seat valves for enabling alternative connection of the at least two pressure chambers of the rotary-piston hydraulic cylinder with a system to obtain the desired rotation.

Abstract: The present invention relates to a device for actuating an automatic device comprising a plurality of combined mobile members, wherein this device comprises an electric motor actuating a hydraulic master jack which in turn actuates a plurality of hydraulic slave jacks connected to said mobile members.

Abstract: A vane-type rotary actuator in which a disc like seal member made of an elastic material with a hole provided in the middle thereof is pressed in place in contact with a flange surface. With seal material thus somewhat deformed in the radial direction thereof, pressure required for sealing is generated at the inner surface of a cylinder and the outer surface of a shaft cylinder.