Abstract: A powered axle for a work vehicle with a dual wheel arrangement includes an axle housing, an axle hub mounted to the axle housing, and an output hub having opposite axial ends supported by one or more wheel bearings for rotation about the axle hub along a rotation axis. An electric drive is disposed, at least in part, within the axle housing, and a hub gear set is disposed, at least in part, within the axle hub and configured to transmit power from the electric drive to the output hub for rotation of the dual wheel arrangement. A wheel brake disposed radially between the axle hub and the output hub and axially between the ends of the output hub is configured to selectively permit and arrest rotation of the output hub.

Abstract: Cylinder sensor assembly includes a sensor with pressure pipe extending from the first sensor axial face of a sensor body, an annular face seal adapted to be disposed between the first sensor axial face and an endcap external axial face, and a sensor retention assembly. The sensor retention assembly includes a plurality of fasteners and a retainer body having a retainer distal face, a plurality of through holes and an internal chamber with a radially-extending flange extending into the internal chamber with the internal chamber open to the retainer distal face. The sensor body is disposed within the internal chamber adjacent the radially-extending flange.

Abstract: An inner cylinder inside an outer cylinder is disposed to be coaxial to an air pressure supply rod inside the inner cylinder. A first piston is disposed between the air pressure supply rod and the inner cylinder, a pneumatic chamber is disposed on a side of one surface (hydraulic surface) of the first piston in the inner cylinder, and a first hydraulic chamber is disposed on a side of the other surface. A second piston is disposed between the outer cylinder and the inner cylinder, and a second hydraulic chamber is disposed on a side of a surface of the second piston which is provided in the same direction as the hydraulic surface of the first piston in both of the cylinders. The inner cylinder is provided with a communication hole for transmitting a negative pressure along with movement of oil with which the first hydraulic chamber and the second hydraulic chamber are filled. In this configuration, it is possible to shorten an overall length of a fluid pressure cylinder.

Abstract: A compensator device includes a hydraulic cylinder with a first end, a second end and an inner cylinder rod extending axially from the second end; and a piston rod with a piston movable axially within the cylinder. The inner cylinder rod has an end with a blocking diameter. The piston rod is generally hollow and includes a cavity to receive the blocking diameter of the inner cylinder rod.

Abstract: A rotating shifting element arrangement for an automatic transmission of a vehicle, having a cylinder element (2), is proposed, in which an actuating piston (3) for actuating a shifting element (1) is arranged in an axially movable way, a compensating cavity (4) of the shifting element (1) being provided by way of the actuating piston (3) and an oil dam (5), and wherein the oil dam (5) is fixed radially outside the piston face (6) of the actuating piston (3).

Abstract: A multi-capacity hydraulic cylinder includes a hollow cylinder closed by a cylinder head, an annular piston moveable within the hollow cylinder to divide the interior of hollow cylinder into a first chamber and a second chamber, a hollow piston rod coupled to the piston and aligned with an opening in the piston, and a secondary rod moveable within the hollow piston rod to define a third chamber in the hollow piston rod, where the third chamber has a cross-sectional area that is less than the cross-sectional area of the first chamber.

Abstract: A two piston cylinder providing asymmetrical expansion and retraction capabilities is disclosed having two linked expansion chambers and a single chamber for retraction. The retraction chamber is situated between the two expansion chambers, and the expansion chambers are linked together by a tube passing through the piston that provides hydraulic fluid to both the retraction chamber and one of the expansion chambers.

Abstract: The invention relates to a hydro-pneumatic piston accumulator (1), particularly for vehicle suspension systems, consisting of an accumulator housing (2) and a separating piston (6), which is disposed free-floating inside the accumulator housing in a displaceable manner in the direction of the movement axis (4). The separating piston separates an accumulator area (8) for a hydraulic medium from a pressure area (10) that is filled or is to be filled with a compressible medium, and is guided with an interior guide opening (30) on an elongated guide element (32), which is axially fixed within the accumulator housing (2).

Abstract: A two piston cylinder providing asymmetrical expansion and retraction capabilities is disclosed having two linked expansion chambers and a single chamber for retraction. The refraction chamber is situated between the two expansion chambers, and the expansion chambers are linked together by a tube passing through the piston that provides hydraulic fluid to both the retraction chamber and one of the expansion chambers.

Abstract: An apparatus for lengthening an extendible pipe comprised of first and second pipe portions having an interior includes a cylinder having an end wall and an open end connected to the first pipe portion. A piston is received in slidable and sealable engagement with the cylinder and is connected to the second pipe portion. The piston, cylinder and end wall define a chamber that is physically isolated from the interior of the pipe. Introduction of a control fluid into the chamber displaces the piston relative to the cylinder so as to lengthen the pipe. The apparatus above may be applied to a sprinkler head riser apparatus and buried as part of an in-ground sprinkler system.

Abstract: A multi-part piston for a brake saddle of a hydraulically and/or mechanically and/or electromechanically actuated disk brake is described herein. The piston is a pot open on one side and including a base and a wall attached thereto in one piece. The base can be impinged by brake pressure coming from the inside of the pot so that an outward-facing abutting surface of the base can be pressed against a brake lining. The inside of the pot receives at least one pressure piece associated with a parking brake mechanism. For simplified manufacture in the form of a modular piston system for use in various applications, it is proposed that the pressure piece and the base comprise conical surfaces facing one another for transferring braking pressure.

Abstract: A cylinder assembly is disclosed. The cylinder assembly may include a cylinder body having an internal cavity therein and a piston and rod assembly disposed for axial movement within the internal cavity of the cylinder body. The piston and rod assembly may have an axial passage extending therein. The cylinder assembly may further include a tubular element received within the axial passage of the piston and rod assembly. At least a portion of the tubular element may extend out of the axial passage and into the internal cavity of the cylinder body between the axial passage and a wall of the cylinder body.

Abstract: This invention is a bi-directional hydraulic actuator comprising a piston assembly positioned within a housing. The piston assembly is configured to move linearly within the housing. A gland is operatively connected to the piston assembly. The gland is configured as a rigid longitudinally annular member with a first end, a second end, a sidewall and is open on the first end and substantially closed on the second end which forms an inside and an outside of the annular member. The gland is further configured with a lip extending from around the outside of the first end of the gland. A pressurizing fluid exerts pressure on the inside of the gland to move the piston assembly a first direction, then, a fluid exerts pressure on the outside of the gland and the lip of the gland to move the piston assembly opposite the first direction.

Abstract: An ultrathin cylinder includes a cylinder bore formed in a short columnar cylinder body and having an axial length smaller than its radius, a short cylindrical piston for sliding in the cylinder bore and also functioning as a piston rod, a guide rod positioned at a central portion of the cylinder bore and passing for sliding through an end wall of the piston to extend into a cylindrical portion of the piston, a rod cover fixed to an end portion of the guide rod in the cylindrical portion to slide in the cylindrical portion, a first pressure chamber defined in the cylinder bore by the piston, and a second pressure chamber defined in the cylindrical portion by the rod cover.

Abstract: To enable economical production of a piston for a piston pump, the piston is made from a tubular deformed part and a closure plug, which is press-fitted with a protrusion into the deformed part. The piston has the advantage that the piston can be made without metal cutting in the form of deformed parts, for instance by extrusion, and hence can be produced quickly and economically.

Abstract: A concentric slave cylinder for use in a clutch actuator in which the housing of the slave cylinder is a two-part construction with one of the members having an injection molded polymer member. In one embodiment, both the inner and outer cylindrical members forming the annular chamber for the piston are formed as injection molded polymer members; in a second embodiment, the outer cylindrical member is formed as an injection molded polymer member and the inner cylindrical member is formed as a cold formed steel member; and in a third embodiment, the inner cylindrical member is formed as an injection molded polymer member and the outer member is formed as a cold formed steel member. The use of injection molded members reduces the cost of the housing assembly and the use of a two-part construction allows the provision of a small annular chamber for receipt of the piston.

Abstract: A concentric slave cylinder for motor vehicle manual transmissions in which the cylinder housing is fabricated from an inner cylindrical member having a base flange and an outer cylindrical member having a base flange wherein the annular fluid chamber between the outer wall of the inner cylinder and the inner wall of the outer cylinder has a radial dimension of not more than about 4 millimeters.

Abstract: A combination cylinder and pistons wherein the pistons are provided with piston rods coaxially located in the cylinder so that fluid under pressure may be introduced into the head of one of the pistons at one end of the cylinder and transmitted through a tubular opening coaxial with said piston rod to the space above the head of the next adjoining piston and if desired, through similar openings in a plurality of additional pistons, until the last piston rod which is not provided with such an opening therethrough and which is connected to a tool.

Abstract: A forming die set has one or more independently operated hydraulic actuator assemblies mounted directly in one of the die shoes to enable a programmed piercing pattern to be carried out at the time the workpiece is formed. Each actuator assembly includes a compact self contained actuator, in which both a piston and piston rod and a punch retainer are slidable in different sections of a housing bore with supply and return connections both through an end cap of the cylinder housing with a return flow path through a tube extending through the piston. The piston rod extends through an annular rod gland member positioned in the cylinder housing bore, and has an end protruding through to a punch retainer to which it is coupled. The punch retainer is slidable in a section of the cylinder housing bore. A purging system using a check valve in the supply line establishes an incremental flow back to the reservoir eliminate air bubbles.

Abstract: A compact drive cylinder with a cylinder barrel, an end cap and a guide cap is provided. In the cylinder barrel an axially sliding piston is arranged, on which a piston rod is mounted which extends through the guide cap. The piston divides a thrust chamber off in a fluid-tight manner chamber from a return chamber, the thrust chamber being connected with a thrust chamber port and the return chamber being connected with a return chamber port respectively in a fluid-tight fashion. Both the thrust chamber port and also the return chamber port are arranged in the end cap. An axially extending abutment rod having an abutment extends through the end cap and has its internal end extending through the piston into the return chamber so that an abutment for the piston is located in the return chamber.

Abstract: A LDT dry well consisting of a stainless steel tube closed at one end and welded to an adapter piece on the opposite end is attached is threaded into the rear of the cylinder and the stainless steel well extends into the cylinder. Inside the tube, the LDT is mounted and threaded into the adapter on the rear of the well. The device therefore seals the LDT from the hydraulic fluid and permits the removal of the LDT from the cylinder without loss of any fluid. The cylinder can be maintained at pressure during and in operation during the replacement operation even though the feedback device is removed.

Abstract: A space (32) is formed between an inner end of a fitting hole (31) formed in a piston (21) and a piston rod (22) and is positioned radially inside a sealing member (24). By circulating a cooling fluid through the space, the majority of heat which is transmitted to the piston rod (22) can be absorbed, preventing transmission of heat to the sealing member. The temperature of the sealing member is kept lower and its deterioration can be inhibited.

Abstract: An air-powered actuator having a body with first and second ends, an axially transverse annular bulkhead positioned therebetween, and an output shaft with a splined exterior portion. The body includes first and second end walls with each end wall having a sleeve mounted coaxially within the body about the shaft and projecting axially inward within the body. A piston sleeve is disposed for axial reciprocating movement within the body. The piston sleeve has a pair of piston heads, an outer sleeve, and an inner sleeve. The outer sleeve is mounted coaxially within the body inward of the bulkhead and about the first and second sleeves to define therewith a fluid-tight outer chamber containing the piston heads, each positioned to an opposite side of the bulkhead to define four fluid-tight chambers and to which pressurized air is applied. Also defined is a fluid-tight inner chamber containing lubricating oil. The outer sleeve is attached to the piston heads for reciprocating travel therewith.

Abstract: A piston assembly employs a central velocity tube which provides an increase in speed of the initial downward stroke phase while requiring less power than conventional hydraulic cylinder assemblies. A second stage hydraulic surge causes the piston to forcefully descend the final increment of the downstroke for an increase in power of the piston. The return or upstroke of the piston is of conventional hydraulic design.

Abstract: A rotary/linear fluid actuator includes a cylinder closed at one end by a rotary actuator and at its other end by a forward housing. A piston is disposed in the cylinder. A hollow piston rod, the forward end of which is closed, extends out of the cylinder through the forward housing. A splined shaft extends into the open end of the piston rod and is coupled to the rotary actuator. The splined shaft includes an axial bore therethrough for delivering pressurized fluid to the piston rod cavity to cause extension of the piston. The piston, cylinder and forward housing define a cavity which is pressurized to cause retraction of the piston. According to the invention, the size of the piston surface can be selected independent of the size of the piston rod cavity actuation surface so that extension and retraction forces, and thereby fluid requirements are independent of one another.

Abstract: A piston assembly employs a central velocity tube which provides an increase in speed of the initial downward stroke phase while requiring less power than conventional hydraulic cylinder assemblies. A second stage hydraulic surge causes the piston to forcefully descend the final increment of the downstroke for an increase in power of the piston. The return or upstroke of the piston is of conventional hydraulic design.

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 closing mechanism of an injection molding machine has a piston-cylinder unit to be pressurized hydraulically. Two partial strokes can be carried out in the unit, of which the first can be run through faster than the second. A displacement tube (7) extends into a main cylinder chamber (6) and into an inner cylinder chamber (4) of a piston (2) of the piston-cylinder unit. The displacement tube (7) is fastened to an end wall of the main cylinder (1) and is open at its free end. The piston (2) is designed as a plunger and is spaces on all sides from the cylinder wall (5) of the cylinder (1) of the piston-cylinder unit. The piston (2) is guided in a flanged gland (15) which is screwed to the cylinder (1).

Abstract: A multi-chamberal hydraulic cylinder and valve system utilizes a single relatively low flow rate pump to provide pressurized fluid during travel, compression and retraction of the piston rod. The piston rod has an effective diameter greater than its physical diameter due to the additional forces applied on an annular piston which is also used to extend and retract the piston rod without supplying pressurized fluid to the interior of the hollow piston rod except during the compression portion of the stroke.

Abstract: A scraper control system for conveyor belt cleaning includes a pair of elongated scraper elements mounted at opposed ends to a pair of spring-biased arms. The sraper mounting arms are attached to a separate shaft at each side of the belt. Each shaft is torqued by one of an identical pair of torque activator units. Each torque activator unit includes an extensible bellows member adapted to be placed into communication with a regulated, high pressure source of water, such as mine waste water. The bellows member has a mounting are fixed relative to the frame of the conveyor and a moveable torque are connected at one end to the bellows member and fixed at a seond end to the shaft. High pressure water preferably mine waster water is regulated between 15 to 100 psig and introduced into the bellows member to cause the torque arm to exert a force on the shaft which, in turn, transmits the force through the spring-biased mounting arms to the scraper elements.

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: A drilling unit comprises a housing (5), a drilling spindle housing means (3) axially moveable within said housing (5), a driling spindle (2) rotatably received within said housing (5) and driven by a driving means (12), a plunger (15) connected to the drilling spindle housing means (3) and piston means (22) slideably received within said housing (5) and operatively connected to the plunger (15). The plunger (15) is connected to the piston means (22) with a first clearance (51) in a plane normal to the direction (A) of the axial movement of the plunger. The piston means (22) further is connected to the plunger (15) with a second clearance (52) in the direction of the axis (A) of said drilling unit. The drilling unit exhibits excellent linearity of axial motion combined with a high degree of accuracy and, at the same time, requires as little space as possible in a plane parallel to a plane, in which a workpiece is positioned.

Abstract: A composite hydraulic cylinder apparatus which has a pneumatic cylinder mechanism, a braking oil hydraulic cylinder mechanism associated concentrically with the pneumatic cylinder mechanism, an oil passage for communicating between the front chamber and the rear chamber of the oil hydraulic cylinder mechanism, and a control valve provided in the oil passage for controlling the flow of the oil. Thus, the apparatus provides high positioning accuracy, a large holding force, economy and small size as a movable element control system, and can be applied as a buffer for the movable element.

Abstract: The present invention provides a kind of pneumatic combined with hydraulic brake chamber, especially relating to a powerful hydraulic brake chamber which is highly stable, ready to provide high-pressure and high-speed actuation and easy to be assembled, dismantled and maintained powerful hydraulic. Said pneumatic type brake chamber is consisted of the following major parts:______________________________________ a cylinder body, a cylinder cover, a central shaft, a shaft sleeve, a piston, a helical spring, a connecting rod, a coupling device, and an alarm device, ect. ______________________________________in which, the pneumatic mechanism is constructed by said cylinder body, cylinder cover, shaft sleeve, piston and helical spring; the hydraulic mechanism is constructed by said central shaft, shaft sleeve, piston and helical spring; and the connecting mechanism is constructed by said connecting rod and the coupling device.

Abstract: An annular seal of the four point type in which a pair of annular seals are provided on one side of the seal to provide an effective pressure seal for the associated pressure chamber and a further pair of seals are provided on the other side of the seal to preclude the entry of contaminants into the sealing interface. The seal is formed as an assembly including a rigid insert ring member and an annular seal member of elastomeric material having a rectangular configuration in transverse cross section defining the four separate annular sealing surfaces at each of its four corners. In one form of the invention, the annular insert member comprises a discrete ring member which is substantially totally encapsulated by the surrounding elastomeric material and in a further form of the invention the insert member is constituted by the free annular end portion of an annular piston member to which the elastomeric sealing material is bonded to form the seal assembly.

Abstract: A drive apparatus useful in screw injection molding apparatus is disclosed. The apparatus is particularly useful when both axial and rotational movements are required because the invention discloses a construction that reduces the wear attributed to sealing gaskets of relatively large diameter which are subjected to rotational stresses and relatively high linear velocities. In the injection molding embodiment described in detail, the extruder screw is rigidly attached to a drive piston that has both axial and rotational movements. Concentric to that drive piston is a drive cylinder tha has only axial movement yet is connected to the drive piston such that the piston is able to rotate freely relative to the cylinder but may move axially only when the cylinder moves. Thus, the sealing gaskets of the drive cylinder are free of rotational stresses which extends the useful life of the sealing gaskets.

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 spring brake actuator for a rail vehicle brake unit, comprising a cylinder and a rod shaped member. The actuator includes a cylinder-shaped housing, a piston with a piston rod and a spring intended to act in a brake applying direction.In order to obtain a truly modular system the actuator, as an integrated and self-contained unit, is arranged on the rod-shaped member of the brake unit. Its housing is attached to the brake unit cylinder. The actuator piston rod is tubular and slidable on the rod-shaped member.

Abstract: A brake actuating mechanism includes a housing defining a cylinder and a tubular piston, slidingly sealed within the cylinder. A pull-rod passes through the piston and is provided at one end with member for connection to a brake linkage mechanism. The other end of pull-rod is provided with abutment member which engages one end of a guide spool, the other end of the guide spool engaging the end of the piston. A pivot member is provided between the guide spool and the piston to permit rocking of the guide spool and pull-rod relative to the piston. A lever mechanism may act on the guide spool to provide for mechanical actuation of the brake.

Abstract: A pneumatic booster of the type including a power piston partitioning the interior of a casing into a front chamber and a rear chamber, a reinforcing rod connected to the casing and extending through the front chamber, the power piston and the rear chamber, and a poppet valve for introducing atmospheric air into the rear chamber and actuated by an input shaft which is slidably mounted on the power piston and extends rearwards out of the casing. A passage is formed in the reinforcing rod with one end communicating permanently with a space into which atmospheric air is introduced through the poppet valve when it is actuated, a cut-off valve is provided for communicating or cutting off the passage in the reinforcing rod, and an air introducing device for introducing atmospheric air into the rear chamber is provided independently of the poppet valve.

Abstract: A system for actuating a clutch by axial movement of an actuating member which is rotatable about a clutch axis with the axial movement for actuating occurring via engagement of the actuating member with a clutch release bearing, the system including a fluid actuated clutch release bearing assembly actuable along a central axis which is generally in line with the clutch axis, and with the clutch release bearing assembly including alignment means separate from the clutch release bearing for moving the axis of rotation of the clutch release bearing substantially into alignment with the clutch axis and with the clutch release bearing assembly including a housing member having an annular, axially extending cylinder portion having a cylinder cavity adapted to receive a piston for reciprocation therein, the cylinder portion being integral with the remainder of the cylinder housing whereby the need for a seal between the cylinder portion and the connecting portions of the cylinder housing is obviated and with the sy

Abstract: A master cylinder construction for automotive brake systems incorporating a servo mechanism in which the master cylinder consists of primary, secondary and fast fill pistons arranged in tandem, the fast fill piston operating in a bore of a larger diameter than that of the primary and secondary pistons the arrangement being characterized in that the fast fill piston is of hollow annular construction consisting of an inner cylindrical wall and an outer cylindrical wall joined together at one end and defining between them an annular space open at the other end, the outer wall being arranged to stroke past a seal into an annular cavity at one end of the master cylinder surrounding part of the bore of the primary piston of the master cylinder and to displace fluid therefrom. The primary piston is constructed to move simultaneously within its bore and to displace fluid therefrom to initiate movement of the secondary piston.

Abstract: An infinitely variable power transmission mechanism comprising a driving sheave assembly and a driven sheave with a torque transmitting drive belt connecting the sheaves, a ratio controlling servo for changing the effective pitch diameter of the sheave assemblies, a belt loading servo for controlling the load capacity of the belt and relatively reduced friction diaphragm actuators for adjustably positioning movable sheave portions of the sheave assemblies, the belt and sheave assembly portions of the mechanism being in a housing area that is isolated from gearing portions of the mechanism.

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 combined brake cylinder/air reservoir device in which a relatively small, tubular-shaped piston in a positioning chamber is connected to a larger power piston having an application chamber on one side and a release chamber on the other side in which air is stored in place of separate reservoirs. A replaceable cylinder liner is provided to receive different-sized power pistons. During a brake application, the power piston enters the cylinder liner and is displaced from the liner during brake release to provide free air flow between the application and release chambers and thereby facilitate piston return movement by means of a return spring. A dynamic pressure seal between the application chamber and positioning chamber engages the outer periphery of the tubular-shaped small piston, while a smaller diameter dynamic pressure seal between the release chamber and atmosphere engages the inner periphery of the tubular-shaped small piston.

Abstract: A downhole, electro-hydraulic pump assembly, having a hydraulic power piston connected to a double-acting production piston is disclosed. Hydraulic power for operating the power piston is developed downhole by a mechanical pump which is driven by an electrical motor carried within the pump housing. The electrical motor is energized by high-cycle electrical power conducted from a surface facility for increased pumping capability in very deep wells. Long stroke capability is provided by an annular piston and a tubular connecting ram which ride on a tensioned guide tube. The effective production piston area is maximized for efficient production in both up-stroke and down-stroke by conducting the flow of formation fluid produced in the down-stroke through the bore of the tensioned guide tube.

Abstract: In a cylinder with two-step movement there is in a housing (7) a first piston (6) which slides in contact with the inside of the housing. A second piston (10), which supports a piston rod (11), which moves sealingly through a first end-piece (8) also slides against the inside of the housing. In the second end-piece (9) of the housing, there is a pressure medium tube (12) passing through the first piston (6) and which extends with its end distant from the second end-piece (9) into, and is guided against the inside of the tubular piston rod (11).

Abstract: An hydraulic jack having more than two chambers is disclosed and is intended for use in a system of jacks, the displacement of which is to be synchronized. Each jack has a cylindrical center cavity in which a piston with a cylindrical cross section reciprocates, an annular cavity in which a piston with an annular cross-section reciprocates, and a rod for transmitting thrust connected to both pistons. In order to provide the jack with a minimum longitudinal dimension and with maximum rigidity, the two cavities are concentric and are separated by a stationary intermediate wall. The two pistons are connected to the rod for the transmission of thrust.

Abstract: A continuous mining machine cutting head structure is set forth. The mining machine is of a type having a support member and an elongated mining head member mounted on the forward end of the support member. The head member is powered for rotation about its longitudinal axis. The head member is of the type having axially extensible and retractable end portions. Included within the head member is a hydraulic piston cylinder arrangement for selectively extending and retracting these end portions. At least one latch element is included within each side of the head member and can be moved into locking engagement with the end portions when it is in an extended position thereby preventing retraction thereof. Also included is a mechanism operatively connected to the piston cylinder arrangement which is capable of moving the latch element out of engagement with the end portion thereby permitting retraction thereof.

Abstract: In vacuum brake boosters for motor vehicles, the vacuum casing is conventionally made of sheet steel. The vacuum casing is subjected to mechanical and pneumatic forces which have to be absorbed by the casing components. This makes it necessary to construct the casing components so they are strong enough to take these forces. The result of such construction is, however, high costs and high weight. To eliminate these disadvantages, the invention provides a brake booster wherein the vacuum casing includes a pipe therein extending in approximately coaxial of the longitudinal axis of the vacuum casing and connected to the transverse end walls of the vacuum casing, the pipe enclosing the master cylinder push rod, and the movable wall of the brake booster is sealed relative to the pipe and slidable thereon.