Abstract: Actuator (14) drives inlet vanes (22) selectively to three positions, using high (58) and low (56) pressure fuel as the driving medium. Each of the three position is externally adjustable (94, 92, 68). An overboard leak path (86) is provided at the most often sliding seal.

Abstract: A fluid-powered rotary actuator having a body with first and second ends, and a shaft extending generally coaxially within the body. The shaft is supported for rotational movement relative to the body by bearing races formed on the shaft first and second end portions and corresponding bearing races formed on a pair of first and second end caps. First and second stop rings are disposed within the body, each adjacent to a corresponding end cap, with the shaft extending therethrough. The stop rings are each freely and longitudinally movable on the shaft within a limited axial range. The stop rings are positioned using set screws which extend through the end caps and engage the stop rings at selected longitudinal positions within their limited axial ranges. When the first and second stop rings are positioned, they engage and limit axial travel of the piston sleeve toward the end caps, and hence provide preselected and adjustable and rotational limits for the rotational travel of the shaft.

Abstract: In an hydraulic cylinder for vehicle braking elements, a clamping piston (1) moved in a housing (3) by hydraulic pressure acts relative to a brake lining carrier bearing a brake lining, e.g., in the form of a brake shoe which, during braking, is forced against the brake disk. To prevent the clamping piston (1) in rest position from being pushed back into its housing (3) by axial impact forces, the clamping piston (1) can be coupled at its interior to an hydraulic volume, which, in the neutral position of the clamping piston (1), acts as an hydraulic cushion and counteracts the impact forces.

Abstract: A fluid injection system is disclosed. The fluid injection system incorporates an injection pump comprising an adjustable restriction device that is used to control the extent of the movement of the pumping mechanism in the injection pump. An adjustable gauge and an adjustable marker are used to accurately calibrate and accurately position the adjustable restriction device. When the adjustable restriction device is accurately calibrated and correctly positioned, a precise amount of additive is injected into the pipeline.

Abstract: A rotary actuator includes a plurality of interchangeable and essentially identical modular drive units each having a pair of racks operably rotating a drive shaft such that the torque applied to the shaft is evenly divided between the drive units. The shaft has pinion-type teeth of a length to accommodate the number of drive units needed to develop the required shaft torque. End plates sandwich the drive units therebetween and rotatably support the shafts. An internal channel system routes hydraulic fluid simultaneously to the proper ends of the racks of each of the drive units to translate the racks in unison. A position sensor identifies the rotary position of the shaft and provides such information to the control mechanism. A rack biasing mechanism for each rack provides biasing pressure against an associated back of a rack directly opposite the shaft and includes a roller acting on the back of the rack. A differential pressure sensor arrangement is provided to sense rotary loading of the shaft.

Abstract: A piston drive e.g. for actuating a valve includes a piston which reciprocates in axial direction within a housing between two end positions, with one end position being defined by a worm drive including a manually actuated worm which actuates a worm wheel movable in axial direction and defining a stop for the piston. The other end position is defined by a gear which is arranged in the path of movement of the piston and is provided with an internal gear meshing with the external thread of a stationary connecting piece of the housing. The gear is turned relative to the connecting piece and thus moved in axial direction by a tool which is insertable through a bore in the housing from the outside.

Abstract: Presented is a fluid drive motor that may be attached to a conventional garden hose, for instance, to effect reciprocating motion of a drive shaft that may be connected to a utilitarian device, such as a scrub brush. The fluid drive motor is provided with a piston assembly that responds to the pressure of the fluid to translate the piston assembly from one position to another and in so doing imposes rotational reciprocation on a drive shaft that extends out of the motor block of the fluid drive motor. The reciprocating characteristics of the piston assembly are controlled by the imposition of fluid pressure, and the imposition of fluid pressure is controlled by a valve assembly cooperating with a reciprocable magnetic bar to channel fluid under pressure alternately to opposite ends of the piston assembly.

Abstract: A fluid pressure actuator having two connected pistons movable in a cylinder, and having a gear rack associated therewith to engage a pinion attached to the shaft to be rotated. Adjustable travel stops are located on each end of the cylinder to control the position of the actuator at the end of the stroke. Each stop has a pair of stop plates which have ramps on the mating faces such that rotation of one stop plate relative to the other adjusts the thickness of the pair, thereby adjusting the position of the end stop for the piston.

Abstract: A pneumatic piston/cylinder unit comprises primary and secondary pistons operable in first and second cylinder zones respectively. Each of the primary and secondary pistons divide its respective cylinder zone into two chambers, one of the chambers of the first cylinder zone being connected to one of the chambers of the second cylinder zone via a passageway which includes at least one control for the flow of hydraulic fluid therethrough. A tertiary piston is provided in the one chamber of the first cylinder zone and divides that chamber into two parts, one of which is between the primary and tertiary pistons. In use the passageway, the one chamber of the second cylinder zone and the other part of the one chamber of the first cylinder zone are filled with hydraulic fluid. Application of pneumatic pressure to the other chamber of the first cylinder zone causes the primary piston to be displaced until it abuts the tertiary piston whereupon movement of the primary piston may be arrested or controlled.

Abstract: A geared air actuator comprising a piston mounted for movement within a housing. The piston has a front wall and a hollow body portion which extends rearwardly from the front wall. A spring is mounted within the hollow body portion of said piston. When pneumatic fluid is introduced into the housing and against the front of the piston, it moves the piston back against the action of the spring. When the introduction of pneumatic fluid is terminated the spring will move the piston back to its original position. The front wall of the piston is substantially thinner than the length of the body portion.

Abstract: An enclosed adjustable servo-actuator is provided. This servo-actuator includes an elongated hollow cylinder; a first closed end member; a second closed end member; a through passageway is provided in each closed end member; an enclosed housing attached exterior of the hollow cylinder at or near the center of the cylinder, said housing adapted to comunicate with the interior of the hollow cylinder; an elongated piston assembly is slidably carries interior of said hollow cylinder; A torque arm is arrayed to engage said piston assembly by means of a closed-end transverse groove provided in said piston assembly; an output shaft is journaled in said enclosed housing, said output shaft engages said torque arm for converting the linear displacement of the piston to an arcuate rotation of said output shaft; and an adjustment means is provided to selectively limit the arcuate rotation of the output shaft.

Abstract: A brake actuator has a body containing a pair of brake-applying members which may be actuated hydraulically to separate the friction elements of a brake into engagement with a rotatable braking surface. The members are interconnected by a mechanism in the form of a shaft of which respective end portions are provided with reversible threaded portions of opposite hand which engage corresponding threads within the members, the shaft being constrained against axial movement between bearings. Any excess movement of one of the members relative to the other is transmitted to that other member such as to cause an opposite and proportional force on the other member to substantially equalize the wear rates on the friction elements.

Abstract: The coupling between a sub-sea pipeline valve and its actuator is brought about by the adoption of a device (4) associated rigidly with the housing of the valve and provided with a hollow shaft (6) into which the valve shaft is keyed. The top of the hollow shaft affords a ring of dogs (7) designed to engage matching dogs (8) carried by a sleeve (9) driven by the pistons of the hydraulic actuator through a mechanical linkage, so that the movement which opens and closes the valve is transmitted through an easily coupled and decoupled dog-clutch; the stationary part of the device (4) is provided with torque reaction lugs (20, 21) which occupy sockets (22) formed in the casing of the actuator.

Abstract: A steering angle limiter is built into an auxiliary power steering mechanism wherein the limits of steering can be variably preset to any predetermined degree within limits in a continuous manner. The limiter is a device built into the power cylinder. Such device comprises a mechanism having threaded telescopic members. One member is axially fixed and manually rotatable by a tool exteriorally of the cylinder to axially shift the other member to a predetermined distance from a respective end of the power piston. The other member may be non-rotative and threaded to the first member or it may be rotative but threaded to the housing. In either event, it is guided for axial movement. The axial setting of the other member effects a limit stop or abutment for the moving piston for such distance of movement as desired to limit the steering angle of the vehicle wheels in a particular direction of steering. For a double acting cylinder a steering limiter as described is provided for each end of the cylinder.

Abstract: An improved fluid supplying and exhausting arrangement for fluid-powered rotary motion actuating devices of the dual piston rack-and-pinion type. A first conduit arrangement includes a central opening through an axial end wall of the actuator housing and a fluid transfer tube fitted in such opening and extending axially through the adjacent piston into the intermediate fluid chamber between the two pistons for delivering fluid and exhausting fluid from the intermediate chamber, with the adjacent piston being slidable on the transfer tube in sealing contact therewith. A second conduit arrangement includes another axial opening in the end wall into the adjacent outward chamber of the housing and another transfer tube fixed to and extending axially through one piston and extending axially through the other piston to open at the opposite ends of the tube into the two outward fluid chambers of the device, with the other piston being in axially slidably sealing contact with the second tube.

Abstract: The invention relates to an actuator, comprising:a cylinder,one or two pistons reciprocally movable in that cylinderone or two racks, each carried by a piston,a pinion coupled to the rack(s),an output connecting part coupled to that pinion for connecting to a device for driving, such as a butterfly valve,means for connecting to a line for medium under pressure for causing the pistons simultaneously to move towards or move away from one another, thereby causing the execution of a corresponding pivoting movement of the output connecting part, andresetting spring means for forcing the pistons into a terminal rest position.The invention provides an actuator with the feature that the resetting spring means comprise at least one gas spring which is connected between the cylinder and a piston.

Abstract: The actuator comprises an actuator body including a cavity in which there are housed two pistons movable in opposite directions and including toothed portions meshing with a toothed pignon rigid with a shaft to be coupled to the spindle of the valve element to be actuated, there being moreover provided end of stroke abutment members which can be adjusted from the outside of the body and which are engaged by the pistons in order to adjust the opening and closing srokes of the valve element.

Abstract: The chuck or collet actuating apparatus for a machine tool comprises a rotating clamping cylinder, an axially slidable clamping piston rotating with the clamping cylinder and a coaxial cylindrical projecting portion in the clamping cylinder. The projecting portion carries a thread, on which a threaded ring is guided and engaged. This threaded ring is provided with a coaxial undercut annular groove in an opposing surface facing the clamping cylinder and is securable against rotation on the projecting portion. A plurality of stop pins are provided which are axially unshiftable relative to the threaded ring and which engage and slide in the annular groove. The stop pins project through an opposing wall of the clamping cylinder into an interior space of the cylinder axially slidable and sealing axially. These stop pins form a stop for the clamping piston limiting its displacement.

Abstract: The present invention relates to a reciprocating engine which has an improved reciprocating double ended piston which substantially reduces the size and weight of piston components. The double ended piston comprises a center portion between the two end portions. The center portion having at least one pair of racks located along the longitudinal axis either on the outside surface of a pair of flat surfaces or on opposed inside surfaces along a slot cut into the center portion. At least one crankless drive shaft having a gear or pair of gears mateable with the racks so that the crankless drive shaft (s) are continuously rotated.

Abstract: To reduce space requirements, vibrations and certain stresses in a motion converting mechanism, a rod is constrained to reciprocate within a housing where the rod is attached to the crankshaft by a cylindrical shaped connector that orbits around the crankpin in a direction opposite that of the crankshaft while rotating inside the rod. Through the center portion of each stroke, the connector also interfaces directly with the housing by such means as a cam cam-follower or gearing to eliminate a second degree of freedom at midstroke. The resulting motion defined for the center of the connector and the rod is sinusoidal being twice that of the motion of the crankpin in the axis of reciprocation. The resulting stroke is four times the crankpin offset.

Abstract: Device for transforming the alternating motion of a piston into a circular motion of a shaft with the possibility of predetermining the stop time of the piston at each of the two dead centers. It is comprised of an assembly of two pistons connected by two racks alternatingly in mesh with a toothed sector keyed on the shaft. On either side of said sector there is provided a cam of which the groove takes charge of the pistons, through rollers at the two dead centers.

Abstract: A sprinkler, connected to a water supply conduit, oscillates by the force of a piston moving in a cylinder and powered by water bleed in a bypass line from the water supply to the cylinder. The piston is connected to a rack which is engaged with a pinion that is attached to a sprinkler nozzle so that water is sprayed from the nozzle in an oscillating spray responsive to the reciprocation of the piston in the cylinder. A first compression spring is operative to return the piston to a home position after a power stroke. The piston has a discharge passageway covered by a valve piece on the pressure side of the piston. The valve piece is supported by a stem slidably disposed in a bore in the piston. A head is fitted to the opposite end of the stem and a tripper compression spring is aligned with the head so that as the piston expands the head compresses the tripper spring until the force of the tripper spring overcomes the water pressure holding the valve piece closed.

Abstract: A fluid motor actuator of the type in which an actuator member is moved in either one of two opposite directions from a rest position to an actuated position includes a fail-safe mechanism having compression springs coupled with the actuator member for compression of the compression springs in response to actuation of the actuator member in either of the two opposite directions for establishing a restoring force which, upon loss of motive power, will return the actuator member to the rest position and maintain the actuator member in the rest position pending restoration of motive power.

Abstract: An improved power actuator with lost motion arrester for coupled use in accomplishing remote control, set, and set hold of rotary flow control valve adjustments wherein the lost motion arrester component is comprised of a circular rack and pinion timing gear assembly that functions to allow smooth mechanical operation during displacement of the power actuator to accomplish valve adjustment, but upon any valve adjustment set stop instantaneously provides in coupled combination with the power actuator assembly a positive mechanical lock and hold function in arresting the lost motion action by which operational adjustment and set of the power actuator mechanism is made.

Abstract: A pivotation device for a centrifugal chain assembly of a motor vehicle comprises a drive, a rack longitudinally displaceable by the drive, a gear wheel forming with the rack a gearing, an output drive shaft driven by the gear wheel and a pivotation arm, connected thereto by a coupling, for the centrifugal wheel of the assembly. A guide rod of round material extends parallel to the rack, which is guided in a flying manner on the guide rod. The teeth of the rack are located at the side facing away from the guide rod and the gear wheel supporting the rack against a lateral pivotation about the guide rod.

Abstract: A hydraulic device includes a piston slidable within a cylinder. Fluid under pressure is admitted to one end of the cylinder through an inlet which contains a restrictor. The piston is formed with an orifice and is biased by a first spring towards the one end of the cylinder. A thrust rod is engageable by the piston to transmit the movement of the piston to an external mechanism. When the piston is moved by rising fluid pressure the orifice is closed by the end of the thrust rod so that a higher value of fluid pressure is required to effect the initial movement of the piston than is required to allow the return movement of the piston.

Abstract: The invention relates to a piston and cylinder unit whose piston rod is provided with a rack extending along it. The rack is in mesh with a ring of teeth (such as the teeth of a toothed belt or the teeth of a gear wheel) adapted to revolve about one axis (in the case of a gear wheel) or about at least two axes (in the case of a toothed belt). Such meshing engagement takes place in every position of the piston rod. When the piston rod is moved in the direction of its length the ring of teeth revolves about at least one axis and rotates a means for influencing the motion of the piston rod. Such means may for example be a liquid brake or a synchro transmitter connected with a NC unit controlling the supply of driving fluid to the piston and cylinder unit.

Abstract: A rotating drive mechanism for swinging doors, especially on vehicles, with a helical transmission consisting of a stator that is rigidly connected to the housing of the rotating drive mechanism, a rotor that can rotate but cannot move axially and that is rigidly connected to the driveshaft, a coupling component that moves axially to rotate the rotor in relation to the stator, and a pneumatic or hydraulic drive cylinder with a piston rod that is connected to the coupling component. The drive cylinder is an annular cylinder that has an outer and an inner jacket as well as an annular piston between the inner and the outer jacket. The coupling component is a nut that extends into the inner cylinder jacket and surrounds a rotor in the form of a threaded spindle. The rotor extends coaxially through the inside of the inner jacket and is, where it emerges from the housing, in one piece with the stub of the takeoff shaft.

Abstract: Disclosed is a piston-stroke adjusting mechanism of a hydraulic tool comprising an oil tank, a ram for causing the forced feed of an oil, and a piston permitted to slide by the pressure of a working fluid. The piston is formed with a through bore into which an adjust pin is slidably inserted in a manner that an end thereof is directed toward the bottom of a cylinder. The piston is rotatably mounted with an adapter at its head section. The adapter has a small-diameter portion at one side thereof which is located in the through bore to be connected to the adjust pin.

Abstract: A stroke limiter for a hydraulic cylinder comprises two sleeve portions each having a channel located therein that are frictionally mounted to the piston rod adjacent to the piston. An elongated contactor is slidably received in each of the channels. The contactor is longer than the sleeve portion and extends past the bottom of the sleeve. The top of the sleeve is provided with a cutout portion which is adjacent to the contactor and provides a hydraulic fluid flow path from the piston mounted poppet valves. When the contactor contacts the end cap of the cylinder, the contactor slides upwardly in the sleeve and contacts the poppet valves in the cylinder unseating the valves and creating a hydraulic fluid flow path across the piston.

Abstract: A rotary actuator for a damper shaft controls the angular position of the damper shaft in accordance with variations in fluid pressure inside of the actuator. The actuator includes a housing, a flexible diaphragm within the housing separating it into a fluid-tight compartment and a second compartment open to the atmosphere. The fluid-tight compartment is provided with a fluid pressure receving port open to a control source of variable pressure. The piston and piston rod are slidably mounted in the second compartment in contact with the diaphragm. The piston rod includes a longitudinally extending rack, and a crank arm rotatably mounted in the housing has a gear segment in meshing relationship with the rack. The actuator shaft to be controlled extends through the housing and is mounted in the crank arm to support the rotary actuator, and the rotary actuator is clipped to an air conditioning duct to prevent it from rotating on the damper actuator shaft axis.

Abstract: An apparatus for readjusting first and second adjustable pressure relief poppet valves to vent the fluid pressure moving a piston when the piston is at the ends of a second work stroke which is of a length less than a first work stroke for which the poppet valves are adjusted. Each of the poppet valves is carried by the piston and includes a valve seat and a valve member movable relative to the valve seat. The piston is disposed in a fluid chamber defined by a housing. The piston divides the fluid chamber into first and second chamber portions. One of the chamber portions is pressurized and the other is vented to move the piston in a work stroke. The apparatus includes a member supported by the housing for moving the seat of the second poppet valve outwardly relative to the piston in response to the member moving relative to the housing and engaging the seat of the first poppet valve to move the seat of the first poppet valve inwardly relative to the piston.

Abstract: A lifting apparatus includes two pairs of lift arms having respective displaced pivot points on a movable carriage for projecting such carriage up into a refuse-receiving opening of a garbage truck, and in an inverted position so as to dump the contents of a receptacle held on such carriage. The two pairs of arms are also axially nested in a co-planar orientation when the carriage is in its fully lowered position, so as to minimize the overall width of the lifting apparatus. A particular hydraulic rotary motor having a relatively thin width may be used to actuate the apparatus. The hydraulic rotary motor utilizes meshed rack and pinion teeth generally within the confines of a cylinder thereof for minimizing the width of the cylinder block. Also, the rack and pinion teeth remain enclosed within such cylinder immersed in hydraulic fluid passing therethrough so as to lubricate the moving components for prolonging their service life with less maintenance.

Abstract: A fluid operated device includes a cylindrical housing whose opposing ends are closed by suitable end covers and which accommodates a piston rod supporting a piston and made of at least two parts connectable to each other. One of the parts of the piston rod and the cylindrical housing are each provided in sufficient length to allow a subsequent shortening thereof to an axial length which corresponds to the requested stroke. The other components of the device are finished parts so that the fluid operated device can be provided in kit form which is not limited to carrying out one specific stroke but rather is adjustable for providing a stroke of any requested magnitude.

Abstract: Conventional piston-cylinder hydraulic actuators require external pressure sources. The hydraulic actuator disclosed utilizes the centrifugal head developed in its chambers. The piston (36) is attached to shaft extension (24) which is splined to the actuator cylinder (20). The cylinder (20) rotates with the shaft (16) to develop a centrifugal fluid head which is selectively directed from the outlet port (40a, 40b) of a contracting chamber through a servo valve (46) to the return passageway (46b, 46a) of an expanding chamber to axially displace piston (36) and shaft (16). An accumulator in the fluid circuit retains fluid displaced from the cylinder (20).

Abstract: The casing of the jack is divided into two cylinders by a cross partition, with a first piston which moves in one of the cylinders and a second piston, forming two parts, linked by a rod which crosses the partition to its first part which moves in the first cylinder-shaped piston and its second part which moves in the second cylinder of the jack. The fluid is conveyed selectively either to the cylinder formed by the first piston or to the second cylinder which communicates with the first cylinder through holes drilled in the partition.

Abstract: An actuator for variable adjustment of the pistons in hydraulic slave cylinders for regulation of for example the elevation adjustment of work stations. The pistons are actuated by way of a pusher which is non-rotatable but axially displaceable in the actuator housing (10). In the housing (10) there are provided one or more oblong openings (22) for drivers (27) attachable to the pusher and arranged for cooperation with the corresponding pusher in one or several further actuators placeable close to the actuator and that in at least one of the connected actuators there is arranged a threaded spindle for cooperation with a pusher designed as a nut.

Abstract: There is disclosed a combined servo control and jack unit which comprises a casing, an actuated piston slidably disposed in a piston chamber and having a piston rod extending outwardly of the casing. A servo valve chamber, axially parallel to the piston chamber, has slidably mounted therein a spool and also a sleeve member which is mechanically connected to the piston rod. Shifting the spool in either axial direction directs hydraulic fluid to one or the other side of the piston, thus moving the latter until spool stopping, at which time the sleeve automatically, almost instantly, blocks off the flow in the new position. A variable speed, gradual action of the piston is obtained without hydraulic shock or cavitation.

Abstract: A fluid pressure operated motor having a piston rod located in parallel offset relationship to the axis of the cylinder is provided with a fixed guide rod extending through the cylinder between the end caps in parallel offset relationship to the cylinder axis. The guide rod passes in sliding sealed relationship though a bore in the piston formed within like outwardly flared frusto-conical counterbores at each end. Complementary opposed frusto-conical locator members coaxially mounted at spaced fixed locations on the guide rod are seated respectively in the counterbores in the piston at opposite ends of the piston stroke to accurately locate the piston axially, radially and rotatively relative to the cylinder at each end of its stroke.

Abstract: A linear to rotary actuator is disclosed having a fluid pressure operated diaphragm whose linear movement is translated into rotary movement of an output member by a helical coupling therebetween. The coupling comprises a coupling member that is insert molded in the diaphram so as to extend therethrough and interlock therewith while preventing fluid from passing from one diaphragm side to the other. The coupling member has a combined guide and anti-rotation portion extending from one side of the diaphragm that slidably engages a stationary guide so as to guide linear movement while preventing rotational movement of the coupling member and further has a helix extending from the other side of the diaphragm that slidably engages in a slot in a section that meshes with a gear connected to the output member whereby linear movement of the diaphragm forces linear non-rotational movement of the coupling memmer and thereby rotary movement of the output member.

Abstract: A linear to rotary actuator is disclosed having a fluid pressure operated diaphragm whose linear movement is translated into rotary movement of an output member by a helical coupling therebetween. The coupling comprises a coupling member that is insert molded in the diaphragm so as to extend therethrough and interlock therewith while preventing fluid from passing from one diaphragm side to the other. The coupling member has a combined guide and anti-rotation portion extending from one side of the diaphragm that slidably engages a stationary guide so as to guide linear movement while preventing rotational movement of the coupling member and further has a helix extending from the other side of the diaphragm which in one embodiment slidably engages in a slot directly in the output member whereby linear movement of the diaphragm forces linear non-rotational movement of the coupling member and thereby rotary movement of the output member.

Abstract: The present invention provides a variable displacement pump including a cylinder member, a piston member slidably received in said cylinder member, a rack rigidly mounted on one of said members and extending parallel to the longitudinal axis of said one member, a pulse motor having an output shaft, said output shaft including a pinion rigidly connected therewith and engaged by said rack, one of said cylinder and piston members being formed with an opening used in both the suction and discharge of a liquid, and check valves disposed respectively between said opening and an upstream source of liquid and between said opening and a downstream discharging system, whereby the displacement of said pump can be controlled by controlling electric input pulses to said pulse motor.

Abstract: A pressure actuated hydraulic seal ring is disclosed for sealing to a rotating cylindrical member. The seal ring clears the rotating member when no hydraulic fluid is applied to its outer diameter. When hydraulic pressure is introduced to its outer diameter, a net compressive force is applied to the seal ring causing it to collapse in radially. The rotating cylindrical member includes a port through an external cylindrical surface which communicates with a conduit in the wall of the cylindrical member. The seal ring includes two inner sealing surfaces which straddle the port in the cylindrical surface where the ring is non-rotatingly supported by a ring retainer disposed about the exterior of the cylindrical surface. A passage extends from the outer diameter of the seal ring to a channel between the two inner sealing surfaces.

Abstract: A pneumatic and hydraulic cylinder includes a precision adjustment mechanism for precise adjustment of piston rod extended position. The rod is slidable within a sleeve, which is screw threaded or otherwise adjustably mounted to the cylinder. The sleeve includes a stop for the piston, adjustably establishing the extended position.

Abstract: A rotary actuator of the rack and pinion type having a two-piece rack and piston assembly. This rack and piston assembly comprises a rack insert and a one-piece piston member, which includes a piston at each end, a connecting strut extending from one piston to the other and means for retaining the rack insert in such manner that the rack is free to float in any direction except longitudinally but is constrained from longitudinal movement.

Abstract: A rack-and-pinion steering gear structure for a vehicle including a rack housed within a cylinder and driven by means of a pinion shaft, comprises an annular piston received with suitable axial clearance in an annular groove defined by three surfaces, namely the end face of one end of the rack, a seating surface of a head of a bolt screwed into a boss projecting from the end of the rack, and the outer periphery of the boss itself. An elastic annular seal member is interposed between the inner periphery of the piston and the outer periphery of the boss.

Abstract: A hydraulic door closer has a housing including a bore and a piston supported for reciprocal sliding movement within the bore in door opening and closing directions corresponding, respectively, to opening and closing movements of an associated door. The piston has a head at one end and an open opposite end which receives a portion of a spring which biases the piston in its door closing direction. First and check second check valves within the head comprise part of a fluid control system for checking movement of the piston during at least a portion of its travel in either its door opening or door closing direction.

Abstract: The method relates to the manufacture of a piston. This piston comprises a head and a stem extending transversely with respect to the head. A profiled element in bar form is first taken, the profile of which envelops that of the piston. This profiled element is cut up into slices, the width of each slice being at least equal to the maximum diameter of the piston, and the material of the profiled element slice which extends relatively beyond the desired profile for the piston is removed by machining. The method is particularly useful for manufacturing remote-controlled actuators for valves.

Abstract: A rack-and-pinion steering gear structure for a vehicle including a rack housed within a cylinder driven by means of a pinion shaft, comprising: a bolt having a threaded portion screwed in a threaded hole formed in one end face of the rack and a shoulder linked integrally with the threaded portion and smaller in diameter than the rack but greater in diameter than the threaded portion; and a piston housed within a groove formed by the shoulder of the bolt, the seating surface of the bolt head, and the end face of the rack, with clearances with respect to the groove in the axial and radial directions.

Abstract: Apparatus for incremental cylinder length control in hydraulic seismic vibrators having increased frequency range. The vibrator apparatus (10) of the type having a reaction mass (38) and axial cylinder bore (42) utilizes hydraulically movable end sleeves (86 and 96) in each end of the cylinder bore (42) so that the end sleeves (86 and 96) can be controllably positioned thereby to alter the cylinder volume and adjust the hydraulic drive system (18) for maximum efficiency relative to operating frequency.