Abstract: A piston-cylinder device, such as a Rankine cycle engine, is provided with one or more variable displacement cylinders and variable stroke pistons for accommodating loads of variable torque. Cylinder displacement is varied by a movable cylinder head internally of the cylinder and auxiliary to a fixed cylinder head, and piston stroke is varied by a variably fulcrumed lever linking piston connecting rods with a crankshaft. For the engine particularly, load torques are continually sensed and cylinder displacement adjusted accordingly. In turn, the position of the movable cylinder head is continually sensed, and the lever fulcrum adjusted accordingly.

Abstract: A high pressure gate valve apparatus provides an elongated cylindrical valve body providing a fluid conveying linear cylindrical longitudinal bore of substantially uniform configuration. A gate valving member is movable within the valve body entirely within the confines of the valve body and not projecting laterally therebeyond. The valve member is movable at generally right angles to and intersecting the fluid conveying bore with the gate valving member providing a flow opening therethrough, the valving member being movable within the valve body between open flow and closed flow positions. A pair of spaced generally parallel cylindrical drive chamber is provided on the valve body substantially parallel to the central flow conveying bore.

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.

Abstract: An idle control valve (10) for adjusting the idle position of a vehicle throttle lever includes a housing (12) having a pair of diaphragm assemblies (18, 20) which divide the housing into three chambers (22, 24, 26). The chamber (26) defined between the diaphragm assemblies is communicated with atmospheric pressure, and the other chambers (22, 24) are communicated with engine manifold vacuum. A valve member (38) controls communication through a vent (74) in the diaphragm assembly (20) to position the latter as a function of the variations in engine manifold vacuum to thereby control the position of the plunger (62) which is attached to the diaphragm assembly (20). The diaphragm assemblies (18, 20) include projecting portions (36, 52) which telescope within one another when the vehicle engine is turned off and atmospheric pressure is communicated to all three chambers to permit the plunger to be withdrawn into the housing.

Abstract: A liquid storage tank for providing a liquid under pressure in such a way that pressurized air will not be absorbed by the liquid is disclosed. According to one embodiment of this invention, the pressurized storage tank of this invention having side walls and an end wall uses a plunger or a plate having a seal which is biased to move within the tank as water or liquid is forced into the tank or withdrawn from the tank. According to this embodiment, springs may be positioned in different arrangements and used to provide the bias that maintains the water or liquid under pressure. Still other embodiments use mass or weight while still others use power actuated means or air pressure for providing the necessary bias. In other embodiments of the invention, the tank may include a seal and/or a collapsable liner to prevent any of the liquid from passing the plunger or piston. The addition of a collapsable liner is especially useful if the liquid to be maintained under pressure is corrosive.

Abstract: An electric power generating system adapted for use in a vehicle including at least one electric generator and one battery; and at least one energy converter for receiving superfluous movement of the vehicle and producing pressure fluid flow from such movement, and a power transmitting means for receiving and changing the fluid flow into rotational power. The power transmitting means transmits rotational power to the electric generator only when stored rotational power reaches a predetermined level. Therefore, the generator is operated by superfluous movement of the vehicle to generate electricity.

Abstract: A piston assembly is mounted at an inner axial end of the toothed portion of a rack within a tubular extension of a hydrosteering gear housing. The piston assembly includes a piston ring floatingly supported with axial clearance on the base portion of a mounting ring axially fixed to the rack at said inner axial end.

Abstract: An adjustment means for variable height adjustment of hydraulically or pneumatically operable supports, e.g. legs on tables, chairs, beds etc., adjustment means for simultaneously raising and lowering all supports and for separately adjusting each of said supports to suit the contour of the floor surface or similar foundation comprised of pressure chambers (13) in the housing (11) of the adjustment means (10), the number corresponding to the number of supports, each pressure chamber having a piston (14), which by way of an adjusting screw (15) cooperates with a driving nut (16), which is unrotatably but axially displaceably arranged in the housing. The driving nut is displaced by means of a threaded spindle (17) which is rotatably but undisplaceably mounted in the housing.

Abstract: Power steering apparatus for a vehicle comprising a rack rod operatively connected to a steering wheel and supported in a steering gear casing, the rack rod being drivable by a power cylinder consisting of an outer cylinder fixed to the steering gear casing, an inner cylinder disposed in the outer cylinder and fitted into the steering gear casing, and a piston mounted on the rack rod to divide the interior of the inner cylinder into first and second oil chambers. A control valve is mounted on the lower surface of the steering gear casing for controlling the operation of the power cylinder. The second oil chamber is in communication with the outer cylinder via the spaces between the coils of a coil spring, the inner cylinder being supported in floating state on the outer cylinder by the coil spring. A pair of parallel, annular or semi-annular oil passages are provided in that portion of the steering gear casing which is engaged with the inner cylinder.

Abstract: A valve driving apparatus comprising a case proper provided in the interior thereof with a movement conversion-transmission mechanism, a cylinder mechanism freely detachably fixed to one end of the case proper and a piston rod supporting mechanism freely detachably fixed to the other end of the case proper so as to be applicable to any kind of valve merely by the replacement of the mechanisms between which the case proper intervenes.

Abstract: A pneumatic operating device, e.g. for controlling valves, includes a cylinder (2) in which a piston (12) is movable. The piston has an axially extending rack part (11) having teeth which engage with teeth on an operating element (10) arranged in the cylinder wall (2b) for rotation transversely of the longitudinal axis of the piston and passing sealingly through said cylinder wall. The piston (12) is provided on the side opposite its rack part with a recess (24) for receiving a part of a spring (26) for the return movement of the piston. The recess (24) extends substantially into the rack part (11) of the piston, preferably through a distance of such length that it extends axially approximately up to or beyond a radial line perpendicular to the piston axis through the center of rotation of the operating element even when the piston is in a position in which the spring is compressed to its maximum.

Abstract: A load relief device for a power steering system of a vehicle. The load relief device provides release of loads from a hydraulic pressure supply pump of the power steering system when the output member of the system is near the end of its stroke by short-circuiting between a hydraulic pressure source and an oil reservoir of the power steering system. The load relief device includes an assembly for detecting the end of a stroke being executed by the power steering system, and upon detection of the end of the stroke, the assembly operates to bring a four-way valve of an open center type to a neutral position thereof, regardless of the steering torque being applied to the power steering system.

Abstract: Rack and pinion power steering gear in which an internal seal having a diameter smaller than that of the power cylinder is press fitted into a reduced diameter portion of the cylinder using the rack and piston as an installation tool.

Abstract: A winding arrangement suitable for sheeting in a sail of a yacht comprising a winch drum and a piston cylinder assembly having a double-acting piston which is reciprocable within a cylinder. A rack member, coupled to the piston, produces unidirectional rotation of the winch drum through a particular clutch and gear system. A manually operated pump is arranged to supply fluid under pressure to the piston-cylinder assembly through supply pipes and a valve which directs the fluid supplied by the pump to opposite ends of the cylinder alternately, thereby to reciprocate the piston and rotate the winch drum.

Abstract: A carburetor vacuum break assembly includes a telescopically constructed adjustable stop which permits adjustment of the carburetor choke vacuum break position but does not require an elongated sealing region about the stop.

Abstract: An arrangement for adjustments on carburetor control devices by which the adjustment is sealed to prevent unauthorized readjustment, leakage or accidental movement out of adjustment by the use of a heat shrinkable tube or cap shrunk into contact with both the adjustment and associated structure to prevent relative movement.

Abstract: A fluid activated pump that is particularly well suited for use in analytic machines of the type that need to accurately meter quantities of sample solutions. The pump, which includes a pump piston driven by a power piston, is powered either hydraulically or pneumatically. Also included in the pump is a displacement adjustment piston, which is either hydraulically or pneumatically controlled, and which, through a suitable shaft-type linkage, can adjust the length of the power piston's stroke, and thus permit either a large or small displacement of the pump piston. The fact that the pump piston's displacement can be changed means that the pump of the present invention can more efficiently meter solutions into various desired ratios, and can reduce the chance of cross-contamination of sample solutions by dispensing a large amount of rinsing solution after dispensing a relatively small amount of sample solution.

Abstract: A power boost mechanism for converting pilot linear throttle input commands to rotary motion and providing amplification of output torque to an engine fuel control and having an output shaft adapted for connection to an engine power lever assembly. An input member is movable in response to a throttle input command and power boost structure responsive to movement of the input member causes rotation of the output shaft. The mechanism further includes feedback structure associated with the output shaft and responsive to movement thereof for returning said power boost structure to a null position independently of said input member, structure automatically enabling direct operation of the output shaft by said input member when the power boost structure is inoperative, and structure responsive to a malfunction in the engine fuel control causing limited rotation of the output shaft without movement of said input member.

Abstract: A rotary power driver is provided which drives with a two-stage torque and speed control, wherein the initial driving is done at higher speed and lower torque, and a subsequent higher torque is automatically imposed with lower speed. The second stage is a selected pre-set stage, with provision for the selected torque built into the driver. The second stage is imposed on the drive shaft by a one-way clutch or ratchet drive.

Abstract: An improved power steering device which has a pinion shaft connected with a steering wheel, a rack rod which is connected with steerable wheels and whose rack is in mesh with the pinion of the pinion shaft in the gear box, a power cylinder for hydraulically actuating the rack rod, and a changeover valve for selectively connecting the first and second hydraulic chambers of the power cylinder with the hydraulic pressure source and the oil reservoir. The pinion shaft is rotatably supported in the oscillating cage which is rotatably mounted on the gear box in a manner such that the axis of the oscillating cage is offset a certain distance from the axis of the pinion shaft, whereby the oscillating cage rotates about its axis when the steering torque is applied to the pinion shaft. The oscillating cage is connected with the changeover valve so that the latter is actuated by the rotary movement of the oscillating cage.

Abstract: The take-out mechanism on a glass container forming machine is operated by the vertical reciprocation of a fluid motor. The movement of the tongs into position to grasp a new container is controlled so that the tong arm which is swinging through an arc of 180.degree. degrees, is cushioned in its final movement so as to avoid excessive vibration of the mechanism.The pressure introduced into the motor for moving the tong arm into position over the dead plate is also connected to a second piston which is spring-biased in relation to the piston rod of the motor. When the tong arm has completed its movement and released the container at the dead plate, the pressure is discontinued at both the motor and the second piston which results in the rod of the second piston actuating the motor rod to cause the tongs to be lifted a predetermined amount.

Abstract: A vacuum motor for controlling a carburetor choke valve in which the stroke of the motor is limited to a predetermined length for a predetermined period of time after which the length of stroke is increased a predetermined amount.

Abstract: A reciprocating piston fluid powered motor providing great flexibility in its mounting and the location of the motor shaft and fluid inlet lines. Relatively few component parts are employed and a number of the components are used as-cast or with minimal machining operations required.

Abstract: A servo cylinder having a piston of the kind having spaced sections which move into an enlarged diameter low pressure bore portion of the cylinder is provided with a gasket assembly for each piston section in the form of an elastic sealing gasket having a resiliently flexible radial flange extending from an integral collar and supported by a rigid ring having a certain circumferential clearance from the collar to permit radial movement for misalignment compensation. The gasket may be formed in the cross-sectional shape of an L or of a T. Where an L-shape is used, a single support ring is provided and where a T-shape is used a support ring on each side of the radially extending flange which forms the leg of the T oriented 90.degree. would be used. The ring or rings are protective of the radial flange in either direction of movement of the respective piston.

Abstract: A rotary actuator apparatus provides compound rotation at its output in two planes perpendicular to one another. This compound rotation is utilized in positioning a workpiece or in positioning a rock drill on the boom of a vehicle. A rotary rack and pinion actuator has an output pinion shaft rotatably mounted in an external housing and a piston driven rack in a cylinder at right angles to the output shaft housing. This cylinder is welded to the output shaft housing so that the cylinder can transmit rotational torque to the output shaft housing.

Abstract: Apparatus for metering material and transferring it from one location is provided. The new metering apparatus has several advantages over that disclosed in my U.S. Pat. No. 4,118,799. The apparatus includes a pair of cylinders with rams which are reciprocated in opposite directions by gear racks connected thereto and driven by a common pinion. A plurality of pairs of the cylinders and rams can be mounted on a common frame or base to meter a number of different materials. Also, the rams, with or without the cylinders, can be readily replaced with components of different diameters to provide different metered quantities of materials. In addition, mechanism are provided for changing the stroke lengths of one or more pair of rams when two or more pairs are employed.

Abstract: A valve actuator has at least one piston in a cylindrical chamber that has a segmental skirt provided with transverse teeth on its chordal face meshing with lengthwise teeth on the hub of a rotor extending diametrically through the chamber with one rotor end exposed and provided with a portion for mating engagement with a valve stem portion when the valve is clamped to the actuator. Air is delivered into the chamber on opposite sides of the piston and the skirt is provided with anti-friction elements. Single and dual piston embodiments are disclosed as well as the use of springs by which the valve is operated in a wanted manner in the event of loss of piston operating pressures.

Abstract: Plastic wear strips are provided on a power steering piston or cylinder to improve the efficiency of translation movement of the piston in the cylinder during operation. The plastic surface of the strip, which is preferably on the piston, minimizes wear by providing a differential molecular structure at the interface between the cylinder wall and the surface of the piston since the cylinder wall is machined metal. The strips are positioned adjacent the ends of the rack where wear, caused by the load from the pressurized hydraulic fluid on the opposite side of the piston adjacent the inlet slot, is potentially the greatest. Plastic filling is provided in preferred arcuate grooves around the piston to form the wear strips. A single strip, or alternatively a group of independent strips, can be used and both serve to interrupt the surface of the piston so that molecular interaction of the two surfaces, or "slip-stick" effect, is effectively prevented. The wear strips extend through a 60.degree.

Abstract: A fluid pressure actuated piston of an aircraft multiple disc brake assembly is adapted to have an extended stroke by telescoping with a pressure actuated cylinder. The piston is slidably carried in a fluid pressure actuated cylinder which, in turn, is slidably carried in a fixed carrier. Initially, only the piston moves axially to extend its stroke with respect to the carrier. The cylinder's structure and axial position with respect to the carrier creates a fluid pressure responsive surface area initially sealed from the effects of the fluid pressure. Axial movement of the cylinder is initially resisted by either mechanical or differential pressure member until the stroke of the piston reaches a predetermined axial position to engage the cylinder. Continued extension of the piston's stroke urges the cylinder axially to break the fluid seal and expose the heretofore unaffected surface area of the cylinder to fluid pressure thereby extending the stroke of the cylinder a predetermined axial distance.

Abstract: A jack comprising a cylinder and a piston, the piston being reciprocal in the cylinder by means of pressure fluid. A piston rod extends out through an end wall of the cylinder. An abutment is fixed to the cylinder or connected to the piston rod. A restricting member, connected to the piston rod or the cylinder, is axially displaceable thereon for engagement with the abutment in any relative position between the piston and the cylinder. A locking device can be connected to the cylinder or the restricting member to lock the latter when engaging the abutment.

Abstract: A fluid pressure actuated device for use with material splitting machines of the type described, the device comprising a cylinder, a double acting piston movable in the cylinder by pressurized fluid, the piston being operatively connectable to the pressure roller of the machine for, in use, effecting withdrawal of the pressure roller from a cutting plane in response to movement of the piston from a first extreme position towards a second extreme position, said cylinder having first and second ports communicating with opposite ends of the piston and arranged so that in use pressurized fluid applied to the first port while the second port is connected to exhaust will cause the piston to move from said first extreme position to said second extreme position so as to effect maximum withdrawal of the pressure roller to permit cleaning of the scrapers and the cutting region, and a third port between the first and second ports and arranged so that in use pressurized fluid applied to the first port while the third por

Abstract: An adjustable stroke piston and cylinder combination including a piston fixed to one end of a piston rod that extends from one end of the cylinder, and an auxiliary piston is in sealed engagement with the cylinder means and the piston rod and is slidable on the piston rod, the piston rod is tubular with pressure supply ports therein connecting its bore to a point intermediate the piston and auxiliary piston while a liquid supply means connects to the one end of the cylinder means to supply pressure liquid intermediate the closed end of the cylinder means and the auxiliary piston to move the same axially on the piston rod to control the effective length of the piston stroke in the cylinder means.

Abstract: A vibration-free hydraulic power system having an opposing pair of pistons adapted to be moved in unison with the same stroke and equal force, but in opposite directions, one of the pistons being operatively connected to an external mass to be moved, the other of the pistons being operatively connected to a reactive mass the weight of which is identical to the weight of the mass being moved, the reactive mass acting to maintain the system in an equilibrium state during its complete operating cycle, the system incorporating a pair of control valves each having a series of sequentially acting valve elements which control fluid flow to and from the system, the pistons and control valves working at all times against solid columns of fluid under positive but variable pressure.

Abstract: Power steering gear with integral rotary valve for directing hydraulic pressure fluid to and from a piston nut and in which a sector gear actuated plunger provides a drag load on piston nut screw so that the valve body will be grounded and the valve spool will be immediately turned relative to the valve body on rotation of the stub shaft before there is lash take-up between the threads of the piston nut and screw which drivingly connect the valve body to the piston nut and sector gear.

Abstract: A fluid pressure actuated piston is slidably carried in a fluid pressure actuated cylinder which, in turn, is slidably carried in a fixed carrier. Forward axial movement of the cylinder is restricted by a hydraulic pressure balance condition which is created by reducing the rearward surface area of the cylinder. The cylinder is maintained in a pressure balanced condition during the entire operation of the piston assembly. After the piston moves axially forward a predetermined distance, it engages the cylinder and urges the cyliner axially forward the same distance traveled by the piston. The piston's maximum axial movement is thereby extended by the distance the cylinder travels. The output force of the piston is substantially unaffected by the force imposed on the cylinder. Also, the cylinder does not provide any work force area.

Abstract: Fluid motor actuator having two pistons reversely movable in a common cylinder, the pistons each carrying at least three extensions on their proximal sides, one of which being provided with a rack camming with one common spur gear fastened on a transverse shaft projecting from the cylinder, the extensions with their outer surfaces lying in one common cylindrical outer surface.

Abstract: A reciprocating sanding and rubbing machine has a shoe portion to which the sanding or rubbing member is attached, this shoe portion being connected through a rack and pinion drive gear assembly to a symmetrically balanced piston assembly which is reciprocally driven by a pneumatic drive. The piston assembly is greater in length than half the total length of the tool, and moves in a carriage block reciprocally relative to the shoe. Two pistons and two associated pairs of compression chambers are employed, one of these pairs of chambers being used for drive in one direction, and the other pair being used for drive in an opposite direction. The pistons are supported on sleeve bearings which align them within the cylinder chamber, thereby minimizing wear on the pistons and the cylinder walls. Reciprocating motion of the piston is achieved by means of pneumatic valving arrangement employing a rotatable valving member which is driven by a rack and pinion gear assembly in response to motion of the shoe.

Abstract: An hydro-mechanical torque amplifier such as a power steering unit for road vehicles. In the prior art, torque amplifying hydraulic pressure was applied to the linear part of a ball-screw geared to the output shaft such that all power went through meshing gear teeth, necessitating robust construction thereof. In the present invention, torque amplifying hydraulic pressure is applied to a vane motor on the output shaft such that hydraulic power does not pass through gear teeth, enabling a lighter and less costly construction.

Abstract: A single tool carrier reciprocatingly driven in opposite directions by a pair of double ended reciprocating pneumatic pistons, one of the pistons driving the carrier through rack and pinion gear means and the other piston driving the carrier through a pin integrally connected to the carrier, mounted vertically on the carrier and engaging the said other piston. Seal rings, preferably of Teflon, are mounted on both ends of both pistons. The pistons operate in opposite directions. One piston is made relatively light so that its weight and the weight of the other shoe are counterbalanced against each other.

Abstract: Worm to rack piston seal for power steering gear having a resilient cylindrical body with internal thread construction conforming to the profile and lead of the worm for a rack piston nut. During powered right and left turns, the seal is pressure loaded radially for improved fluid sealing and relaxed during low pressure conditions when there is no steering input for improved returnability of the rack piston nut to its centered position.

Abstract: A control apparatus comprising a cylinder including therein a piston non-stepwise controllable in terms of the amount of piston portion protruded and the speed of its protruding movement. The amount of piston portion protruded is controlled by an attachment position at which the cylinder is attached to an adaptor for fastening the control apparatus to a device desired to be controlled and the position of a bar extended into the cylinder through one end portion thereof to abut against a piston head. The speed of protruding movement of the piston is controlled by a control fluid fed into and discharged from a cylinder chamber divided by the piston head into two parts.

Abstract: A piston rack rotary actuator, devoid of guiding tubes or rods along which the pistons reciprocate, is provided with guide bearings which eliminate or at least reduce the incidence of the separating forces which otherwise act on the racks (particularly when the pistons are moved towards one another) to displace them towards the cylinder wall and which thereby otherwise cock the pistons in the cylinder and cause scoring of the cylinder wall.

Abstract: A fluid operated stepping motor comprising a cylinder housing having one or more fluid cylinders to alternately displace at least two cam engaging members when pressure from a pressure source is applied to one of the cylinders. The cam engaging members are diametrically opposed. A cam is secured relative to the cylinder housing and having a plurality of teeth asymmetrically disposed thereon, is also provided. Each tooth has a power profile surface and an idle profile surface. The power profile surface is slidingly engageable by one of the cam engaging members when pressure is applied to displace the said one cam engaging member axially whereby the power profile surface will cause relative rotational displacement between the cylinder housing and the cam.

Abstract: An actuator, in which fluid pressure on a piston advances a stem against retractive force provided by a spring, a hydraulic dashpot is provided for the stem, and a stroke varying cushion is used for preventing engagement of a back seat between the stem and housing except when a seal is desired.

Abstract: A hydro-mechanically operated reciprocating spindle for a machine tool is disclosed in the environment of a vertical gear shaper. The spindle comprises a piston which is slidable in a cylinder and which carries a cutting tool at its bottom end. The spindle-piston has two faces of different area to which hydraulic fluid under pressure is directed, the larger area face being used to drive the spindle downwardly in the cutting stroke, and the smaller area face being used to drive the spindle upwardly in the return stroke. Further, the spindle-piston has an axial bore which receives a vertically reciprocable valve. The valve is reciprocated by linkages driven by a rotating shaft, and the arrangement is such as to drive the valve downwardly and thus to move the spindle downwardly at a controlled velocity and under a controlled hydraulic force, and then as the valve is moved upwardly the spindle is moved upwardly on the return stroke at preferably a higher velocity.

Abstract: A rack and pinion power steering gear is disclosed which includes a manifolding arrangement to eliminate external fluid connections between the power steering valve and the cylinder. The manifolding arrangement includes a tube which is received within the steering housing. The diameter of the tube is less than the diameter of the housing in which the rack is received so that an annular fluid passage is defined between the outer circumferential surface of the tube and the inner circumferential surface of the housing. The annular passage communicates fluid the entire length of the rack mechanism, so that fluid may be selectively admitted to opposite sides of the piston depending upon the direction which the vehicle wheels are turned. The manifolding mechanism further includes a sleeve which extends into the tube and which is provided with passages extending therethrough to communicate fluid pressure to the other side of the piston.

Abstract: Apparatus for the continuous feeding of plural liquids in separate streams of adjustable quantity and ratio, comprises a drive unit that drives a main pump, and that also drives at least one secondary pump. The drive unit has an oscillating or reciprocating movement, and so the pumps are piston pumps or oscillating vane-type pumps. The stroke of the secondary pump or pumps may be selectively shortened without shortening that of the main pump, so as to predetermine the proportions of the liquids to each other. The system is particularly applicable for the feeding of separate streams of synthetic resins by the main pump, and the associated hardeners, catalysts, accelerators or other auxiliary liquids by the secondary pump or pumps.

Abstract: The present invention relates to an improved hydraulic vibrator of the type which includes a fixed double rod piston and a reaction mass reciprocally disposed around the piston forming a hydraulic cylinder therein so that when hydraulic fluid is introduced to the cylinder relative to the piston the reaction mass is reciprocated. By the present invention a pair of sleeves are slidably disposed on the piston rods, portions of which can be selectively moved into the cylinder to decrease the displacement of the cylinder and thereby increase the frequency range of vibrations producible by the vibrator.

Abstract: A pneumatically driven device which in the exemplary form of the invention is an air tool driven by pistons. In the exemplary form there are two pistons having racks which drive the reciprocatable shoe through pinion gears. One piston drives in each direction. Each piston at the end opposite the driven end has an annular groove in it with a sealing ring with ports for communicating air to the area behind the ring for pushing it out against the inside surface of the cylinder. During a piston stroke at this end of the piston air is compressed to provide a cushioning and braking effect which improves the overall operation, and avoids excessive wear.

Abstract: The apparatus of the present invention may comprise a housing or other stationary member which may have a chamber therein. A drive member is disposed in the chamber for movement therein. An elongate torque transmission member is rotatably mounted in the housing so as to extend into the chamber toward the drive member. Means are provided to prevent the torque transmission member from moving longitudinally with respect to the housing. An annular connector is disposed between the torque transmission member and the drive member. The connector is connected to the torque transmission member for longitudinal but non-rotating relative movement and threadedly connected to the drive member. Thus the connector can be moved longitudinally along the torque transmission member during normal or automatic operation of the actuator.