Abstract: A valve spring compressor apparatus for removing and installing valve springs on automotive racing engines includes a valve seat and a compressor pump assembly. The valve seat is placed between the valve spring and the engine housing. The compressor engages the valve spring seat with a support arm and extends a piston toward the valve spring seat, thus compressing the valve spring and allowing for the removal of the retainer ring and keeper lock. The compressor uses a source of compressed air to drive a power piston into a compression chamber multiplying the supply air pressure several times. This multiplied air pressure is retained in the extension piston chamber by a one-way valve. As the extension piston extends, the multiplied air pressure in the extension piston is maintained by repeated cycling of the compressor.

Abstract: An adjusting drive for a transmission of a motorized vehicle has a housing and an adjusting member supported within the housing. The adjusting member has at least three control positions. The housing has at least two valve-controlled connecting adapters for supplying a pressure medium to the housing and loading the adjusting member on two sides. A gear shifting shaft is coupled to the adjusting member.

Abstract: An apparatus for operating a device, e.g. through moving a piston rod. An outer cylinder has an inner cylinder movable between the end walls of the outer cylinder, whereby the inner cylinder is a piston movable in the outer cylinder. An inner piston in the inner cylinder is movable between the end walls of the inner cylinder. First and second fluid flow ducts communicate through the ends of the outer cylinder outside the inner cylinder. Third and fourth fluid flow passages communicate between the outer cylinder and the inner cylinder at the opposite respective sides of the inner piston in the inner cylinder, such that application of gas under pressure to one or the other of the first and second ducts causes movement first of the outer piston in the outer cylinder and then of the inner piston in the inner cylinder for moving the piston rod connected with the inner piston. Details of an embodiment of this staged movement cylinder piston arrangement are disclosed.

Abstract: A multipiece fuel pump plunger assembly for controlling the fuel injection rate and delivery during the initial injection portion of a fuel injection cycle for an internal combustion engine. The injector includes a two piece plunger assembly including a plunger and a plunger sleeve. The plunger having a small predetermined diameter and being slidably positioned within a plunger sleeve having a diameter greater than the diameter of the plunger. The multipiece plunger is advantageous because it allows for shaping of the rate of fuel injected into the combustion process thereby reducing the excess fuel flow in the early portion of the injection cycle. Elimination of the excess fuel flow results in lower oxides of nitrogen and particulate exhaust emission levels and less engine noise.

Abstract: A multiple-stage hydraulic cylinder for shifting loads by exerting different forces over different distances, in which a hollow-piston cylinder is provided with a hollow piston rod. The hollow piston rod accommodates at least one additional long-stroke cylinder. The hollow piston rod, moreover, comprising a cylinder tube surrounding the long-stroke cylinder. Connections are provided for hydraulic fluid to move the cylinders. These connections are provided on the hollow piston rod and the long-stroke cylinder for admitting fluid to move the hollow-piston cylinder and the long-stroke cylinder.

Abstract: A multiple piston hand priming pump includes a plurality of nested pistons engaged within a hollow cylindrical housing. One end of the housing has an inlet/outlet fitting leading to a pumping chamber defined within the housing and the other end of the housing is closed. Through a center bore in the closed end of the housing, a plunger activating rod extends into communication with the centermost piston of the nested plurality of pistons. The nested pistons each engage within the next circumferential piston in a manner forming a lost motion connection therewith at the end of an axial bore in the next piston to cause sequential actuation after the pumping stroke of the inner piston is completed.

Abstract: A steering/lifting appliance (10) for a hydraulic or pneumatic axle compensation appliance configured as a two-circuit system, having a first external jacket tube (12), a second jacket tube (15) inserted in a pressure-tight manner in the first jacket tube (12) and supported so as to be longitudinally displaceable, a piston device (16) present in a pressure-tight manner in the second jacket tube (15) and supported so as to be longitudinally displaceable, a first closed chamber system to which admission can occur from the outside for controlling the relative displacement between the second jacket tube (15) and the first jacket tube (12) and a second closed chamber system to which admission can occur from the outside for controlling the relative displacement between the piston device (16) and the second jacket tube (15) features a torsion device (40) supported in an end region of the piston device (16) and longitudinally displaceable relative to the piston device (16), which torsion device (40) is in engagement

Abstract: A double acting hydraulic jack comprising a housing from which at least two pistons extend, each of the pistons being telescopic with respect to one another and with respect to the housing, and a counterbalance valve between adjacent pistons. The counterbalance valve allows hydraulic fluid to flow from an outer piston to an inner piston during piston extension and prevents back flow of hydraulic fluid, thus eliminating piston retraction during extension under load.

Abstract: A self-bleeding multi-stage or single-stage hydraulic cylinder system is disclosed which automatically bleeds entrapped air from within the cylinder each time the cylinder is cycled. The self-bleeding structure preferably includes a fixed elongated tube mounted to the base plate of the cylinder, and an axially moveable elongated tube telescopically mounted on the fixed tube. A biasing compression spring forces the moveable tube upward to a predetermined extent when the cylinder is extended. Upon contraction of the cylinder, air trapped therein is purged or bled from the cylinder through the top end of the axially moveable elongated tube into a fluid reservoir. In the final stage of contraction of the cylinder, hydraulic fluid is forced through the fixed and moveable elongated tubes thereby forcing the remaining air trapped therein out of the cylinder and into the hydraulic fluid reservoir.

Abstract: A telescoping fluid actuator assembly including a housing having a plurality of concentrically disposed fluid actuators disposed therein. Each fluid actuator includes a cylindrical housing enclosing a piston and piston rod. Fluid passage means is provided for alternately directing fluid pressure to the front and back piston faces of each piston to effect forward and rearward movement of the pistons and the associated piston rod. The innermost concentric fluid actuator has a piston rod extending from the housing for engaging a workpiece for movement thereof. All of the concentrically mounted fluid actuators, except the innermost fluid actuator, is provided with a hollow piston rod which forms the cylinder housing for adjacent concentric fluid actuators.

Abstract: A hydraulic telescoping ram of the type suitable to tip dump trucks and the like, which permits the use of outer aggressive seals and a bore sealing device by providing a conduit which hydraulically connects the upper end of each cylinder of the telescopic ram with an oil reservoir. This makes it possible to use seals which are not aggressive and which can run on surfaces of somewhat less than top quality, on the internal bottom faces of the rams so as to allow the passage of a small quantity of oil into a gap formed within the ram and cylinder and between the aggressive and non-aggressive seals. The oil which passes the non-aggressive seal is returned to the oil reservoir when the ram is extended.

Abstract: An indexing apparatus (10) having a pair of concentric cylinders (12, 14) with the outer concentric cylinder (12) being fixed against longitudinal movement and the inner cylinder (14) mounted for reciprocal movement relative to the fixed outer cylinder (12). A single ram piston (16) is mounted within the inner cylinder (14) and has a piston rod (18) connected to a member (29) for positioning at four predetermined positions. A shock absorber (24) is carried by the outer fixed cylinder (12) and engages stop plates or abutments (20, 28) carried by the inner cylinder (14) for activation of the shock absorber (24). A pair of guide rods (42) prevent rotational movement of inner cylinder (14) relative to the inner cylinder (12) and maintain the shock absorber (24) in axial alignment with the end abutments (20, 28). In one embodiment (FIGS.

Abstract: A multi-stage hydraulic actuator including a cylinder body having an outer cylinder and an inner cylinder provided in the outer cylinder, first and second pistons inserted in the outer cylinder to independently move and provided with first and second working members, and third and fourth pistons inserted in the inner cylinder to independently move and provided with third and fourth working members.

Abstract: A fluid pressure operated friction clutch actuating system for releasing the clutch includes a pressure operator, an actuator mechanism, which mechanism is shown as including a housing having a pair of telescopic pistons acting on a force transmission member and reacting through the actuator housing on an end wall of the clutch housing. The force transmission member has a U-shaped recess through which the clutch output shaft and the bearing retainer pass so that the force transmission member is in force transmitting engagement with the clutch throw out bearing while the system is in its operative position in the clutch housing. The actuator pistons act on the force transmission member when pressurized to move the throw out bearing to release the friction clutch through its belleville spring.

Abstract: A telescopic pneumatic hoist has a flexible stationary hollow probe on its base arranged to unseat a check ball in the piston of the lowest intermediate stage when the piston is near the base. When such a condition exists, the probe closely interfits with the piston and has a radial port communicating with the underside of the piston. The probe connects at the bottom with a supply and exhaust passage which also communicates with the underside of the piston via a check valve controlled secondary passage.

Abstract: A telescopic brake piston includes a cylindrical housing and a pair of concentric pistons. A first hydraulic cavity is provided between an outer piston and the housing, while a second hydraulic cavity, communicating with a source requesting the application of brake force, communicates with both pistons. Passages in the outer piston allow the two cavities to communicate with each other. As the associated brake disc stack wears, the outer piston progressively extends from the housing as the passages are exposed by the inner piston. The actual brake force is attained by the inner piston alone.

Abstract: An improved press assembly has upper and lower draw rings which grip a workpiece. During closing of the press assembly, an improved control assembly accelerates the lower draw ring to a first speed and then to a second speed before the upper and lower draw rings move together. Similarly, during opening of the press assembly, the control assembly decelerates the lower draw ring to a first speed and then decelerates the lower draw ring to a second speed prior to stopping of the lower draw ring. The control assembly includes a two stage piston and cylinder assembly. The piston and cylinder assembly includes an inner piston and a hollow outer piston which encloses the inner piston. The inner piston is engagable with a flange on the outer piston to move the outer piston with the inner piston.

Abstract: Described herein is an internal mixer of the type including a mixing chamber rotatably accommodating mixing rotors therein, a hopper frame erected on the mixing chamber, a charge hopper provided on one lateral side of the hopper frame for charging a mixing material therethrough, and a floating weight provided in the hopper frame for upward and downward movements therein, the floating weight being held in an upper lifted position when charging a mixing material into the mixing chamber and then lowered into a pressing position in a mixing stage to apply pressure on the charged material in the mixing chamber, wherein the floating weight is dimensioned to have an axial length sufficient for closing an inlet opening formed in the side wall of the hopper frame in communication with the charge hopper, when in the lower pressing position, and lift means for lifting the floating weight up and down in the hopper frame is provided separately from a pressing means with a function of pressing the floating weight resilient

Abstract: A three-position hydraulic actuator comprising an outer body defining a cylindrical inner cavity; a dual-rod piston sliding inside the cavity; a pair of stop rings mounted in respective central annular seats in the lateral wall of the cavity and on the piston; and a pair of bushes sliding in sealed manner between the piston and the lateral wall of the cavity and located on axially opposite sides in relation to the stop rings.

Abstract: The present invention relates to a hydraulic valve lash adjuster with which a cam engages directly and in which an oil-introducing chamber can be easily cleaned by a fluid or gas jet stream. In the valve lash adjuster in accordance with the present invention, the cylinder sleeve is formed through its lateral wall with a plurality of openings, and an annular oil-introducing chamber defined between the body and cylinder sleeve is communicated through the openings with the reservoir and consequently with the high pressure chamber. With the above construction of the invention, an extraneous substance such as chips and particles can be removed from the oil-introducing chamber along a fluid jet stream. Thus, since the oil-introducing chamber can be easily and perfectly cleaned by a jet stream during the manufacturing process and moreover during any overhaul work thereafter, reliability and maintainability of the product is markedly improved.

Abstract: Power fluid from a pump are provided through one power fluid branch conduit to an extend port for activating the smallest cylinder of a multi-stage packing cylinder and fluid is conducted through a second extend branch conduit to a second port which provides fluids to the larger cylinders of the packing cylinder. A normally closed sequence value is in the second branch conduit. When the pump first is activated, fluid goes through the first extend branch conduit to extend the smallest stage of the packing cylinder. When the smallest stage is fully extended or reaches resistance, the pressure in the pump output conduit rises. When this pressure reaches a preselected value, the sequence valve is opened and high pressure fluid is directed through the second branch conduit and second port to provide power fluid to the larger cylinders of the packing cylinder.

Abstract: The present invention provides a protective device for a working member, such as the piston rod of a piston and cylinder actuator, which is arranged at least partly in a receiving member and is able to be moved and more especially slid, along a curved or straight path so that it projects to a greater or lesser extent out of the receiving member. The device is provided with a plurality of sleeve-like guard sections which surround the working member projecting out of the receiving member along the full length of the working member so that whatever the position of the latter any two adjacent guard sections overlap each other and are able to be slid in relation to each other, one of said guard sections being stationarily arranged on the receiving member and another guard section being arranged on the working member so as to move therewith so that in accordance with the actual axial extent of the part of the member to be protected the sections are telescoped into each other to a greater or lesser extent.

Abstract: A brake booster which includes a control slide that is displaceably supported in a servo piston and acted upon by a piston rod under the influence of brake pressure. The control slide has bores that establish communication between a pressure chamber and a pressure source or return for power brake fluid in the pressure chamber. The control slide is intended to penetrate a control bush in a stepped bore in the servo piston, which has a radial bore for connecting the pressure source with a radial bore in the control slide toward the pressure chamber. The control bush is supported radially movably in the stepped bore.

Abstract: Herein disclosed is a brake system for use with an automatic transmission for braking a rotatable member such as a brake drum, which is accommodated in a casing and connected to the sun gear or the like of a planetary gear mechanism, by bringing a brake band having two ends into contact with the outer circumference with the rotatable member.

Abstract: An impact type surface seismic source powered by compressed air includes an elongated piston which moves within the bore of a cylindrical firing tube suitably mounted above an earth contacting target. The firing tube consists of two or more tubular sections slidably joined in telescopic relation. When the piston is allowed to fall from a cocked position, compressed air enters the bore above the piston through side ports and drives the piston downwardly. At the same time, the inner sliding section or sections of the firing tube are exposed to the same air pressure within the bore and are also driven downwardly. In this way, the bore of the firing tube lengthens automatically to provide a longer stroke for the piston and thus a greater attained kinetic energy of impact for a given operating pressure as the piston reaches the target. The apparatus is designed for mounting on a transport vehicle so that the firing tube itself may be raised in operation and lowered for reduced vehicle profile during transport.

Abstract: The brake piston return mechanism (10) comprises a housing (22) which includes housing part (50) that forms with the housing a chamber (59) and an axially extending groove (55). Disposed within the axially extending groove (55) and forming a movable portion (58) of the chamber (59) is an annular actuation piston (70). The actuation piston (70) includes a pair of seals (74) to prevent leakage. Within the housing part (50) is a bore (40) enclosing brake tube (80) that includes an interior radially extending flange (84) and an exterior radially extending flange (82). The exterior radially extending flange (82) is engaged by the actuation piston (70). Located within the brake tube (80) is an adjuster mechanism (90). After the brake tube (80) has been displaced by the actuation piston (70) and braking has ceased, the brake tube (80) is returned to a running clearance (A) by way of the adjuster mechanism (90 ).

Abstract: The heretofore known adjusting device for an axial piston pump/motor of a tilting axis type in which a tilt angle of a valve plate is varied by rocking the valve plate along arcuate guide grooves formed in an end cover of the axial piston pump/motor is improved so as to reduce the size of the adjusting device in the direction of its stroke by assembling a sleeve or sleeves and a piston fitting in the sleeve or sleeves in a telescopic structure within a cylinder formed in the end cover along a rocking direction of the valve plate, and by providing a trunnion pin engaged with the valve plate in the piston.

Abstract: A hydraulic piston and cylinder arrangement retains the outer surface of a sleeve forming the piston in dry condition. The cylinder provides an outer wall and an inner stem with the sleeve sliding inwardly of the outer wall and outwardly of the stem. A head on the end of the stem cooperates with the inner surface of the sleeve. A bearing member on the end of the sleeve remote from the head cooperates with the outer surface of the stem. A first chamber is thus defined between the head and a closure cap on the sleeve to provide an expansion chamber. An annular chamber between the outer surface of the stem and the inner surface of the sleeve and closed by the bearing member provides a return chamber. Two fluid channels coaxially arranged within the stem provide the communication of fluid to the chambers.

Abstract: A fluid-pressure-operated, three position working cylinder includes a cylindrical housing having a graduated bore formed therein and a movable primary piston dividing the bore into first and second pressure chambers. A movable secondary piston surrounds a portion of the primary piston and moves relative to the primary piston within the limits of a piston stop arrangement formed on opposing surfaces of the pistons. The piston stop arrangement includes an elastic stop on the primary piston which interacts with a sloped stop formed on the secondary piston so that upon initial insertion of the secondary piston onto the primary piston, the sloped stop compresses the elastic stop. The sloped stop includes a lip portion that can contact the elastic stop so as to restrain the secondary piston from further movement in one direction relative to the primary piston. A vent passage formed in the housing allows venting of the space between the two pistons.

Abstract: A fluid operable power unit which is particularly adapted for movement of a compaction head in a refuse container. However, the power unit is also useful in other types of mechanism.The power unit comprises a plurality of telescopically movable cylinders and pistons. Fluid pressure is applied for movement of the first cylinder. Then increased fluid pressure is applied for movement of the second cylinder. As the first cylinder ceases to move, fluid pressure increases and automatically operable valve means traps the fluid which has moved the first cylinder. Then increased fluid pressure moves the second piston and second cylinder. As the second piston and the second cylinder move under the influence of increased fluid pressure, the fluid which is trapped is increased in pressure.Thus, high pressure forces act to move an actuator member for compaction or for any other purpose.

Abstract: A multistage cylinder having a partial force mode, a full force extended mode, and a full force retracted mode, and having an outer cylinder closed at one end and open at the other, one or more intermediate cylinders located within the outer cylinder, and extendable and retractable with respect thereto, an inner drive member within the intermediate cylinder, and extendable and retractable with respect thereto, intermediate hydraulic fluid conduits in the drive member for flow of hydraulic fluid and from the intermediate cylinder, and an intermediate valve for controlling flow of fluid thereto, outer cylindrical hydraulic fluid supply and return conduits connecting directly with an outer cylinder, separate from the intermediate conduits, and an outer cylinder valve for controlling flow of fluid independent of the intermediate cylinder and a fluid flow barrier between the intermediate cylinder and the outer cylinder so that fluid from the intermediate cylinder is maintained out of contact with the outer cylinde

Abstract: A hydraulic tensioning device for tensioning the rigging of a sailing vessel comprises first, second and third components which are telescopical with respect to one another. A cylinder of the first component and a piston of the second component form a first chamber, and a cylinder of the second component and a piston of the third component form a second chamber, the two chambers being in fluid flow communication with one another via a passage. The first component is connected to one part of the rigging, and the second component to another part of the rigging. The rigging is tensioned by applying tension to a rope or wire connected to the third component. In another embodiment the first component is mounted for guided displacement along a rail, the second and third components each being connected by a rope or wire to a cam cleat to limit longitudinal displacement.

Abstract: Apparatus for filling containers with two products from different sources, using a rotating volumetric filler which picks up first one product then the other, and discharges them both simultaneously into a container. The filler uses a pair of concentric pistons, the central one of which is retracted to pick up the first product as it rotates over an arcuate slot beneath which the first product is stored; the outer, cylindrical piston is then retracted to pick up the second product as it rotates over another arcuate slot beneath which the second slot is located. Both pistons are later extended simultaneously to discharge the combined product into the container. Since the two products picked up by the successive retractions of the two pistons are held beside each other, a more uniform mixture of the two products is obtained than if they are picked up one above the other by a single piston.

Abstract: The actuator (12) comprises three main parts, an outer casing (20), a movable piston (28) and a fixed piston (36). A stepped outer portion (50, 52, 54) of the movable piston (28) cooperates with a stepped cavity (40, 42, 44) in the casing (20) to define a plurality of concentric, variable diameter fluid chambers (1, 2, 3) bounded at their ends by radial surfaces on the movable piston (20) and within the casing cavity. The movable piston (20) and the fixed piston (36) define a plurality of axially spaced apart variable diameter fluid chambers (1', 2', 3') which are bound on their ends by radial surfaces on the fixed piston (36) and radial surfaces within the cavity formed in the movable piston (20). One set of the chambers (1, 2, 3) is connected to supply pressure (P.sub.S) and the second set of chambers (1', 2', 3') is connected to return pressure (P.sub.R). Seal receiving grooves are formed in outer surface portions of the fixed and movable pistons (28, 36). Seal rings (S.sub.

Abstract: A hydraulic servo device with a built-in accumulator, comprising a servo piston fit in a servo cylinder and connected via a stem to a band brake, an accumulator piston having a large diameter outer diameter portion and a small diameter outer diameter portion fit in the servo cylinder at two inner diameter portions thereof having different diameters and an inner diameter portion fit around a small diameter outer diameter portion of the servo piston, and an accumulator piston spring biasing the accumulator piston toward the servo piston.

Abstract: A gear positioning cylinder having forward, reverse, and neutral gear selection provided by a positioning rod attached to a main piston in which an auxiliary piston is telescopically arranged for compactness.

Abstract: A fluid pressure actuated piston (78) is slidably carried in a fluid pressure actuated cylinder (50) which, in turn, is slidably carried in a fixed carrier or casing (21). Movement of the cylinder (50) is resisted by a breakable or displaceable coupler (90, 94, 184, 185) which engages the cylinder (50). Fluid pressure acting upon the cylinder (50) and piston (78) causes the coupler (90, 94, 184, 185) to break or be displaced and release the cylinder (50) for axial movement in the direction of movement of the pressure responsive piston (78).

Abstract: A fluid operated cylinder device particularly adapted to lift a load relative to a load support includes a hollow casing having a closed end for attachment to the load support; an elongated rigid rod extending lengthwise of the casing and having a first end arranged within the casing and rigidly fixed to its closed end and a second end disposed outwardly of the casing for attachment to the load support; at least one open ended fluid operated cylinder arranged intermediate the casing and rod for sliding movements lengthwise thereof, such cylinder having an outer end disposed outwardly of the casing for attachment to the load; and fluid means for introducing and withdrawing fluid from the casing for effecting sliding movements of the cylinder and lifting and lowering of the load. Single and double acting embodiments of the cylinder device are disclosed.

Abstract: A telescopic hydraulic cylinder comprises a hollow base member arranged to be supported pivotally on a mount, as by trunnions, the base member including a removable end closure at its rearward end. The interior surface of the base member incorporates a set of machined grooves which removably mount a set of rings that act as a stop, a fluid seal, a bearing and a wiper for the largest of a plurality of telescoping cylinder stages each incorporating a similar set of internal machined grooves and rings which cooperate with the adjacent smaller stage. The smallest stage receives a piston closed at its forward end which mounts a connector for attachment to a load to be moved.

Abstract: Disclosed herein is a power feed system for translating a rotary drill head along the length of a guide tower. The system utilizes a compound balanced area, end fed hydraulic cylinder as the actuating means. This arrangement provides a large ratio of fixed overall length to usable travel distance, balanced feed force in both directions, direct connection of the rotary head to the outer stage of the cylinder, and drift-free operation, all without the need for moving hydraulic hoses.

Abstract: A brake cylinder comprises a brake actuator device having a fluid operable piston and a coaxial adjoining hand brake operable device for axial actuation of a coaxial tubular push rod, there being a slack adjuster for selectively adjusting the retraction of the push rod. An actuating rod is connected to the piston and the actuating rod is selectively connected and disconnected from the internal periphery of the push rod by locking rollers selectively cooperating with a wedge shaped annulus disposed between the actuator rod and the inner periphery of the push rod. Slack adjustment is permitted by axial travel of the push rod beyond free travel limits as permitted by a friction sleeve connection between the outer periphery of the push rod and the brake cylinder housing. In a modification, the locking device is provided for a fluid spread brake cylinder that is adapted by levers to be connected to a conventional freight brake rigging to be used, for example, for hand brake applications.

Abstract: A pneumatic actuator for deploying flexible bodies and the like is disclosed. The actuator is a plurality of telescoping tubes made of high temperature resistant graphite material which are extended by the pressure of gases produced internally by a gas generator contained within the innermost tube. The extended tubes are locked in position automatically and venting of the gases from the tube interior is provided for simultaneously with full and locked extension of the tubes.

Abstract: There is disclosed a gate valve which is moved to open position by an extendible and retractable, fluid-operated actuator, and which is moved to closed position, upon exhaust of operating fluid, by coil springs which urge follower parts reciprocable with a stem on the gate, and which extend from the valve body into a housing connected on the valve body, into engagement with cam surfaces on the housing. The cam surfaces are so arranged that the coil springs initially move the gate from open toward closed position with a relatively small force, and then move it into fully closed position with a force which is sufficiently larger to shear a wire line or other obstruction in the flowway of the valve body which would otherwise prevent closing of the gate.

Abstract: A double acting telescopic hydraulic cylinder comprises a hollow base member arranged to be supported pivotally and including a removably end closure at its inner end. The interior surface of the base member incorporates a set of machined grooves which removably mount a set of rings that act as a stop, a fluid seal, a bearing and a wiper for the largest of a plurality of telescoping cylinder stages each incorporating a similar set of internal machined grooves and rings which cooperate with the adjacent smaller stage. The smallest telescopic cylinder stage receives a hollow telescopic piston stage closed at its inner and outer ends. An internal groove on the inner end of each telescoping cylinder stage removably mounts a lifting ring for engaging the next smaller stage. An external groove on the inner end of each stage removably mounts a guide bearing ring for cooperation at its forward end with the stop ring of the adjacent larger stage.

Abstract: A pair of axially aligned and nested pistons are mounted in a pressure sealed arrangement within the bore of a pressure housing. A primary piston is moved in response to increasing pressure to provide an actuating output force while a secondary piston simultaneously moves to overcome a reverse bias on it by a tension spring and adds to the actuating force by engaging the primary piston only when the pressure exceeds a specific higher threshold. The primary and secondary pistons thereafter operate in conjunction under the influence of high pressure to provide the output actuating force.

Abstract: A tensioning device, especially for endless chains of a tracklaying vehicle, is provided which is formed as a working cylinder which is connected to a pressure-regulated hydraulic source and whose cylinder chamber, which guides a tensioning piston pressing against the guide wheel, is provided with an outlet comprising a pressure relief valve and an inlet, connected to the hydraulic source, with an incorporated nonreturn valve.

Abstract: A hydraulic ram for use in thrust-jacking of tunnel linings comprises a cylindrical outer member, a cylindrical inner member reciprocable within the outer member, and an extension member reciprocable within the inner member. A two-part clamping ring is provided for releasably locking the extension member to the inner member. An auxiliary drive is provided for retracting the extension member rapidly within the inner member. The auxiliary drive may be a mechanical spindle drive, or a hydraulic drive having an auxiliary piston reciprocable within an axial bore formed in the extension member. The clamping ring comprises spring means for urging the parts of the clamping ring in to the closed position, and piston-and-cylinder means for urging the parts of the clamping ring apart, against the biasing force of the spring means, to open the clamping ring.

Abstract: A track guided vehicle is provided which includes laterally projecting transverse guide rollers mounted on support arms extending in a direction parallel to a direction of travel of the vehicle. The guide rollers are adapted to be retractable and extendable to an operating position through a guide arrangement which is directed diagonally upwardly and inwardly with a bilaterally effective operating element being disposed concentrically within the guide arrangement. The transverse guide rollers are elastically flexible in a transverse direction and are adapted to utilize an on board compressed air system to displace the transverse guide rollers and fluidic operating or working element which is constructed for pneumatic pressure application.

Abstract: A single ended hydraulic actuator requiring hydraulic pressure to extend the piston for raising the cowl door of a jet engine and the like. A preload spring device carried in the piston-rod assembly produces an extend force when the actuator is retracted and the door is closed which preloads the actuator to help eliminate fretting of the bearings and piston rod which otherwise can occur due to flight vibrations when unloaded.

Abstract: A clutch or brake cylinder has an annular working space accommodating an annular piston which confronts a stack of interleaved friction plates adapted to couple the cylinder to a coaxial member rotatable relatively thereto, the piston being displaceable by fluid pressure toward the stack against the force of a Belleville spring. This piston occupies only part of the working space so as to leave an annular clearance in which an ancillary sealing ring is independently slidable. When fluid pressure is applied, part of that pressure pushes the sealing ring against the Belleville spring and lifts it off the piston which then can exert its full force upon the stack of friction plates. Extraction of the cylinder from a surrounding housing enables the piston and the sealing ring to be replaced by a larger piston, filling the entire cross-sectional area of the working space, if a greater coupling pressure is to be exerted.