Abstract: A seal including a metal annular body having an inner diameter and an outer diameter, the annular body including a main body portion including a first lip extending axially from the main body portion, the first lip adapted to provide a radial seal; and a second lip extending radially from the main body portion toward the outer diameter, the second lip adapted to provide an axial seal.

Abstract: Provided are mechanisms and processes for a pneumatic shaft positioning system. According to various examples, the pneumatic shaft positioning system includes a pyrotechnic valve that is configured to control the flow of gas from a pressurized gas source into a pressure chamber. The pressure chamber includes a first piston that is slidably coupled to the pressure chamber. When gas from the pressurized gas source fills the pressure chamber, the piston is configured to slide through the pressure chamber and force a shaft into a predetermined position.

Abstract: The present invention relates to a valve control device (1) having a housing (2), which comprises a first low pressure chamber (3) and a first atmospheric pressure chamber (4), which are separated from each other in a gas-tight manner by means of a spring-loaded first membrane (5); having a control rod (6) for controlling the position of a locking element of the bypass valve (7), wherein the control rod (6) is operatively connected to the first membrane (5), further having a second low pressure chamber (8), which is flow-connected to the first low pressure chamber (3), and having a second spring-loaded membrane (9), which is arranged in the second low pressure chamber (8) and is coupled to the first membrane (5), wherein the control rod (6) is mounted on the second membrane (9).

Abstract: A hydraulic actuator has an armored section having concentric cylinders and an unarmored section having a cylinder with a frangible piston and a frangible upper gland nut. The hydraulic actuator may have leakage vents adapted to prevent leakage between hydraulic systems used to power the cylinders. The hydraulic actuator also may have a gland seal for sealing an end of the cylinder of the unarmored section and a sensing port adapted for allowing detection of fluid leaking due to damage of the gland seal.

Abstract: A pump piston device is for reciprocating movement in a pump cylinder. Between the pump piston and the pump cylinder, an annular space is formed which is defined by a first seal and a second seal, the annular space being pressurized, and the first seal and the second seal being in a common piece of material which constitutes the pump piston.

Abstract: A fluid actuator configured for achieving extended cycle life and reduced overall actuator height. The actuator may include a nesting arrangement between portions of the actuator to reduce overall height and provide stability. The actuator may also join movable members and include a guidance mechanism to avoid undesired contact between actuator portions.

Abstract: A power steering assembly and method of retrofitting therefore includes a housing having a cavity defined therein. A drive member extends axially into the cavity and a first piston and a second piston are received in the cavity for axial reciprocation therein. The first and second pistons define at least in part first and second pairs of chambers. The first pair of chambers receive fluid under pressure to move the first and second pistons toward one end of the housing to rotate the driven shaft in a first direction. The second pair of chambers receive fluid under pressure to move the first and second pistons toward the other end of the housing to rotate the driven shaft in a second direction opposite the first direction.

Abstract: A vibration isolator (200) for isolating a first assembly (206) from vibration from a second assembly (208) includes a first system (202) and a second system (204) coupled to the first system (202). In one embodiment, the first system (202) supports the majority of the first assembly (206) relative to the second assembly (208) and the second system (204) adjusts for a change in the location of the center of gravity of the first assembly (206). Further, the second system (204) can be used to compensate for fluctuations in the atmospheric pressure near the vibration isolator (200).

Abstract: The invention concerns a device forming a mechanism, in particular for use in the space industry, characterised in that it comprises in combination: two structural elements (100, 200) capable of relative displacement, locking means (300) adapted to prevent initially the relative displacement between the two structural elements (100, 200), and means (400) for controlled locking of the locking means (300) designed to prevent initially the release thereof, then when activated, successively, in a first phase, a sliding action in controlled amplitude of the locking means (300), for limited release between the two structural elements (100, 200), then in a second phase, complete release of the locking means (300) and hence of the structural elements (100, 200).

Abstract: A pressure intensifier for generating a relatively large output force includes a piston driven in an advancing direction and a retracting direction. In one embodiment, two pistons are also driven to eliminate the need for a high pressure source. Another embodiment includes a biased piston for urging a ram in the advancing direction. A module for converting a single piston intensifier to a dual piston intensifier is also discussed.

Abstract: A fluid mount (10) for an exposure apparatus (32) includes a first subsystem (12) and a second subsystem (14). The first subsystem (12) includes a first cylinder (18) and a first piston (20). The first piston (20) moves within the first cylinder (18) along a first axis (26). The second subsystem (14) includes a second cylinder (22) and a second piston (24). The second piston (24) moves within the second cylinder (22) along a second axis (28). Importantly, (i) the second subsystem (14) is stacked on top of the first subsystem (12), (ii) the second axis (28) is substantially coaxial with the first axis (26), and (iii) the first piston (20) is connected to the second piston (24) with a piston connector (16). The resulting fluid mount (10) has a relatively high load carrying capacity and a relatively small footprint.

Abstract: A dual linear actuator for allowing a tool to perform multiple actions either simultaneously or independently of one another.

Abstract: An unloader includes a first volume bottle with a cavity formed therein of predetermined volume, and a port in the forward end with a plug operably mounted to selectively open and close the port. A second volume bottle is stacked on the first volume bottle and has a port in the forward end with a plug operable to open and close the second bottle port. The second bottle is arranged such that the second port will fluidly connect the first and second bottles. Actuators are connected to the plugs in the first and second bottles to selectively open only the first bottle or both bottles together, to thereby provide a two stage internal clearance for the reciprocating compressor cylinder.

Abstract: A probe structure for inserting into and operating upon an object within a pipeline, especially a high pressure pipeline carrying liquid or gas, is characterized by two coaxial cylinders that can be either pneumatically or hydraulically actuated. A primary cylinder is adapted to be mounted onto a pipeline tee and/or valve, and includes a movable primary piston to which is fixedly attached a primary lower hollow shaft that moves with the primary piston and preferably a primary upper hollow shaft that also moves with the primary piston. The primary lower hollow shaft is adapted to selectively extend into the pipeline while the primary upper hollow shaft extends above the primary cylinder and is fixed to a secondary cylinder, such that the secondary cylinder moves with the primary piston. The secondary piston includes a secondary piston that moves independently of the first and second cylinders.

Abstract: An actuator having a body defining an internal cavity and a gland disposed within the cavity, the gland being secured against movement relative to the actuator body in a direction along the internal cavity by a securing element located in an opening of which respective parts are defined by the actuator body and the gland, and which allows insertion of the securing element into the opening along a substantially linear path.

Abstract: An automatic two-stage switching valve includes a valve stem which normally closes a fluid passage by a spring force; a cylinder adopted to accommodate the valve stem; a large flow rate piston and a small flow rate piston that are provided on the valve stem and are slidably fitted in the cylinder; a large flow rate pilot pressure chamber formed in the cylinder; a small flow rate pilot pressure chamber formed in the cylinder; a stopper adopted to restrict the movement of the small flow rate piston; a pilot pressure source adopted to apply the pilot pressure simultaneously to both the large and small flow rate pilot pressure chambers; and a restrictor provided in a connection passage that connects the pilot pressure source to the large flow rate pilot pressure chamber.

Abstract: A ram actuating mechanism 20 for a blowout preventer 10, the ram actuating mechanism 20 including a hydraulic booster for enhancing the ram closing force. The ram actuating mechanism 20 may be compatible for use with primary pistons 25 which include internal moving components, such as self locking pistons. The ram actuating mechanism 20 providing a hydraulic booster without increasing the diameter of the booster pistons above the diameter of the primary piston, such that BOP stack height need not be increased to accommodate a relatively large diameter hydraulic booster. The ram actuating mechanism 20 may utilize the same piston housing 60 as used by the primary piston, and the booster pistons 26, 28 may act mechanically in series upon the primary piston 25 to increase axial ram closing force. The ram actuating mechanism 20 may be capable of retro-fitting existing ram actuating mechanisms.

Abstract: A cylinder is divided into two chambers by a wall to receive a pair of pistons. This reduces the stroke length and correspondingly reduces the linear speed of the piston. This leads to a reduced PV factor associated with degradation and wear of the piston rings. Moreover, the multi-cylinder arrangement provides the same performance in an oil-free compressor assembly without appreciably expanding dimensional constraints relative to known systems.

Abstract: An actuator assembly that has a constant net pressure area telescoping piston. The actuator assembly has a cylindrical housing; nesting, telescoping pistons; a central plug; an outer cap; and a vent. The cylindrical housing has an interior surface and a base that terminates at an open end. The nesting, telescoping pistons are located in the housing and can extend past the housing open end. The telescoping pistons have an outer piston slidably sealed against the housing and an inner piston that is slidably sealed against the outer piston. The outer piston has a first end proximal to the housing base, and a second end distal to the housing base. The inner piston has an open end proximal to the housing base, and a closed end distal to the housing base. The central plug extends from the base and into the telescoping pistons. The central plug is in pressurized communication with the inner piston and is engagable with a pressurized fluid source. The outer cap has a first and a second member.

Abstract: In a hydraulically operated steering for a motor vehicle comprising a control motor with first and second double acting piston and cylinder units arranged in axial alignment and a single piston rod extending through the first and second double acting piston and cylinder units, at least one of the double acting piston and cylinder units includes an annular piston which is fastened on the pistons rod in a predetermined axial position and an annular divider wall is disposed between the pistons for slidably supporting the piston rod and separating the cylinders of said first and second double acting piston and cylinder units fluidically from one another so as to form cylinder chambers for said pistons limited at one side by an annular divider wall and by guide sleeve members disposed in the opposite ends of the cylinder units.

Abstract: A durable oil well pump having fitted ceramic cylinders. Two metal retainers are fitted at two ends of the ceramic liner barrels. A cement or adhesive, which is resistant to pressure and temperature is placed in the annular clearance among the liner barrels, the retainers and an outer tube. There are multiple segmented plunger skirt and ceramic barrels to be fitted around a plunger inner tube. The valve seat outer ring is shrunk on to the ceramic inner ring. The valve ball is also made of ceramic. This pump has resistance to corrosion, temperature and magnetic fields. This pump can prevent liner barrel displacement, increase the period between repair, improve oil production, and reduce the cost of production.

Abstract: An improved compensation piston arrangement for use with a dual circuit master cylinder having a single service piston for simultaneously pressurizing a first fluid chamber and a second fluid chamber, wherein the compensation piston arrangement provides for pressure balancing between the first fluid chamber and the second fluid chamber to compensate for minor normal differences between the first and second fluid chamber. The compensation piston arrangement includes a movable compensation piston slidably disposed within a bore of a compensation housing, wherein the housing defines a pair of end stops positioned on opposing sides of the compensation piston. The bore is in fluid communication with the fluid chambers such that the pressure within the first fluid chamber acts on a first side of the compensation piston, and the pressure within the second fluid chamber acts on a second end of the compensation piston which is opposite the first end.

Abstract: An intensifier type of fluid actuator includes multiple sensors for sensing various operational characteristics of the intensifier. The intensifier includes a first manifold connected by a first tube to a second manifold to define an intensifier chamber, a third manifold connected by a second tube to the second manifold to define a reservoir chamber, and a fourth manifold connected by a third tube to the third manifold to define a work chamber. An intensifier piston is disposed within the intensifier chamber and has an intensifier rod secured thereto that extends through the second manifold into the reservoir chamber and through the third manifold into the work chamber. A reservoir piston is disposed within the reservoir chamber and includes an opening formed therethrough, through which the intensifier rod extends. The second body includes a fifth manifold connected by a fourth tube to a sixth manifold to define a piston chamber.

Abstract: A pressure-driven cylinder having a piston sliding within a sealed housing chamber between a pair of opposed side-end walls in a piston chamber. At least one chamber wall has a moveable portion of an end wall integrally connected to and axially spaced away from a pressure-driven face of the piston by an integral connector point that is much smaller in area than the piston's pressure face. That moveable wall portion acts as an integrally connected piston follower that has its own extended surface area that is progressively introduced into the presure chamber as the piston slides in order to reduce the required volume of pressurized driving fluid in the piston chamber. A chamber for the follower itself is sealably isolated from the piston chamber so that no driving fluid backs into the follower chamber. Both the end wall/follower and the piston reciprocate together.

Abstract: A multiple piston and cylinder assembly is illustrated utilizing first and second transversely bifurcated segments (A) and (B) for retention by an intermediate snap ring (D) installed within a single groove (C) facilitating a sealing abutting relation between the segments utilizing a sealing and retaining member (E) wherein the segments are inserted from opposite ends of the cylinder.

Abstract: A piston pump, particularly adapted for use in a system for supplying and dispensing electrically conductive coating material, includes a pump housing having an outer wall, opposed first and second ends and a hollow interior separated into a first cavity and a second cavity by a centrally disposed divider plate. A connector rod extends through a bore formed in the divider plate, and mounts first and second piston heads on opposite ends thereof which move in tandem in a first direction in response to the introduction of coating material into the second cavity, and in a second direction when pressurized air is introduced into the first cavity to discharge the coating material from the second cavity.

Abstract: A rod with a tubular, fibre-composite wall, cut into two parts has actively controllable, pressure- and tension-generating elements which are effective in an axial direction of the rod, provided therebetween. An exterior pressure-generating element, which effects an elongation, takes the form of a cylindrical ring and is disposed on the outside of the rod elements. For the cylindrical ring, stop shoulders are formed on the outside of each of the rod elements. A second force-generating element is disposed inside the rod. Disposed in each of the two rod elements are loops or bends which are axially fixed to the rod elements and are guided around the axially opposite ends of the second force-generating element so that they in each case overlap or extend around the end of the second element which is directed axially away from the rod element in which the loops are fixed. Upon elongation of the second element, tensile forces are exerted upon the two rod elements and draw said two rod elements together.

Abstract: In a hydraulic brake for a transmission, an assist piston, a reaction piston and a main piston are accommodated on a cylinder. The assist piston has a first acting portion in abutment against the main piston, and the main piston has a second acting portion facing one end of stacked frictional engaging elements. The assist piston and the main piston are moved rightwardly by a hydraulic pressure supplied to a first oil chamber and a second oil chamber to bring the frictional engaging elements into engagement with one another. The first and second acting portions are superposed as viewed axially, thereby preventing a jarring of the assist piston and the main piston. In one embodiment, each of the pistons is formed from a pressed article, whereby the machining cost can be reduced and, moreover, oil passages connecting the first and second oil chambers can be provided in a simple manner.

Abstract: A forward-moving inching unit and a backward-moving inching unit are built in a casing (1) which is slidable relative to a guide member (b).

Abstract: A linear actuator has a cylinder body having a slot defined therein, a slide table, a joint connected substantially perpendicularly to a lower surface of the slide table, a pair of pistons slidably disposed in a through hole defined in the cylinder body and defining respective cylinder chambers in the through hole, for displacing the joint in response to a fluid under pressure supplied to one of the cylinder chambers, a guide projecting from a lower surface of the slide table, a pair of spaced guide blocks projecting from an upper surface of the cylinder body, and a plurality of balls rollingly interposed between the guide and the guide blocks.

Abstract: Pneumatic jack of the type comprising a rigid body (1) joined to the outer edge of a deformable membrane (2) so as to delimit with the latter a chamber of variable volume capable of being subjected to either atmospheric pressure of a negative pressure, via an air inlet located in the chamber. The body (1) and the membrane (2) each have, substantially in the center, an opening (15, 14) that can be closed, at least partially, by a disc (4, 3). Application in multiple position jacks.

Abstract: A multi-piston assembly is illustrated wherein a cylindrical housing (A) is ported through longitudinal circumferentially spaced ports (F) and (G) carried within the cylindrical housing. Porting through piston rods is thus avoided so that their cross section may be reduced thereby increasing the area of the pistons available for contact by pressurized fluid. Even greater force may be made available for actuating a tool by the addition of an add-on unit utilizing complementary longitudinal porting.

Abstract: An active positioning element for a rubber mount, including a space surrounded by a housing, a positioning member and a working member which is designed as a spring element arranged within the space. The positioning member and the working member are movable back and forth in the direction of oscillations introduced into the rubber mount, and the positioning member is sealed in the housing. The positioning member is formed by a gas pressure spring which can be acted on by gas under pressure, the gas pressure spring comprising at least one piston-cylinder unit which has a roller membrane for sealing the piston off from the housing. The spring element is formed by a compression spring which, in the direction of the oscillations introduced, rests under elastic initial stress, on one side against the positioning member and on another side against the support bearing of the rubber mount.

Abstract: A sealed piston pump having in an open cavity of the pump body, a circular single-piece set formed by a central cylindrical piston. The piston is coupled by a rod to a driving member while the piston in an alternating motion along its longitudinal axis. A ring is placed on the pump body which is hollowed out with an annular channel and a deformable thinned part connecting the piston to the ring. The single-piece set and the pump body are fixedly joined to each other in an imperviously sealed way. The single-block set is made of a synthetic material that is flexible and mechanically and chemically resistant. The pump can be advantageously used in ink-jet printers.

Abstract: In a pressure-intensifying type fluid pressure cylinder, an auxiliary cylinder chamber is provided outside a rod cover, a pressure intensifying piston is axially and slidably disposed on the outer peripheral portion of a piston rod in the auxiliary cylinder chamber, and steel balls are disposed around the piston rod in space having a tapered surface in the pressure intensifying piston. Or, a lock concave portion is formed on the outer peripheral portion of the piston rod and a lock member is provided in the pressure intensifying piston which lock member makes the pressure intensifying piston and the piston rod one body by being fixed in the lock concave portion. When the piston rod reaches a little before the end of extrusion, fluid pressure comes through a way in the auxiliary cylinder chamber between the pressure intensifying piston and the rod cover.

Abstract: A power cylinder (10) has two pistons (12, 20) slidably mounted within separate cylinders (14, 22) to define inner and outer chambers (16, 18; 24, 26) within each cylinder. One or more rods (28) are coupled between the pistons. The outer chambers (18, 26) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The inner chambers (16, 24) are coupled together to allow pressurized hydraulic or pneumatic fluid to flow therebetween. The fluid flow aforesaid may be achieved by using two hollow rods (128, 130) and allowing the fluid to flow through the rods between the respective chambers. A guard (44) may surround first and second cylinders (14, 22). Bearings (46, 48) may be fixed around the opposed inner ends of cylinders (14, 22) to allow slidable displacement of the cylinders relative to guard (44).

Abstract: The present invention provides a pressure switch assembly for monitoring a source of fluid pressure. In one embodiment, the pressure switch assembly senses a variation of fluid pressure for actuation of a micro-switch to open or close an electric circuit. In another embodiment, the pressure switch assembly provides a self contained cluster of piston members which are selectively interengagable to permit a variety of pre-determined pressure ratings to act on the pressure switch assembly in response to a fluid pressure source, the cluster being manually reorganizable without adding or removing any parts to provide one valve assembly which may be responsive to a number of pre-selectable pressure ratings.

Abstract: The present invention is drawn to an isolation system for separating two diverse fluid mediums from each other and, more particularly, an isolation system for prohibiting leakage of the diverse mediums around the peripheral surface of a piston movably mounted within a chamber. The present invention further relates to an improved multi-piston air-oil pressure intensifier employing the improved isolation system for separating and preventing leakage of the air and oil mediums during operation of the pressure intensifier.

Abstract: This invention relates to a displacing apparatus comprising a plurality of concentric tubular members concentrically disposed about a central axial member. These concentric members define a plurality of substantially closed chambers between adjacent concentric members. A piston member is disposed within each chamber and extends generally radially between two adjacent concentric members thereby dividing each chamber into first and second portions. Each of these piston members is rigidly affixed to one, and sealingly engaged with the other, of the two adjacent concentric members forming a chamber. An actuating means actuates each of the concentric members which has a piston member rigidly affixed thereto. The actuating means selectively provides pressure or vacuum to the first and second portions of each of the chambers creating pressure differentials across the piston members.

Abstract: A hydraulic fluid Pressure-operated actuator comprises a first cylinder assembly having an output which operatively carries a second cylinder assembly such that an axial output force is effected from an output shaft of the second cylinder assembly, the output from the second cylinder assembly is a fast forward output stroke which is followed by a greatly increased high pressure force generated by the first cylinder assembly and effected through the output shaft of the second cylinder assembly.

Abstract: A sealed vehicle wet disc brake has a brake housing and a piston housing which are fixedly interconnected and which receive a rotor. The two housings and rotor define an annular cavity which is sealed by appropriate rotary seals and in which is maintained a friction stack. The piston housing has a plurality of uniformly spaced piston bores therein, such bores being interconnected by an annular groove which circumferentially intersects with a circumferential surface of the piston housing. A pressure source of fluid communicates with the annular groove and the piston received within the bores. The annular groove is sealed by means of an "O" ring engaged therein from the circumferential surface and retained by a retaining ring. The intersection of the annular groove with the circumferential surface is tapered to accommodate compressive retention of the "O" ring.

Abstract: A deep well pump for positioning in a bottom hole assembly and having at least one fluid pump and at least two fluid powered motors with the pump and motor pistons carried in alignment on the piston rod. The pump includes passages for delivering a power fluid to one end of each of the motor cylinders and for receiving exhaust fluid from the other end of the motor cylinders, and a valve for reversing this operation. A first sleeve is positioned around the first motor cylinder defining a power fluid path from one end of the first cylinder to one end of the second cylinder, a second sleeve is positioned around the first sleeve defining an exhaust fluid path from the other end of the first motor cylinder, and a third sleeve is positioned around the second motor cylinder defining an exhaust fluid path from the other end of the second motor cylinder, with the first and second exhaust fluid paths interconnected.

Abstract: A low-impact drive unit operates by air under pressure. It includes aligned working and pressure chambers. The working chamber contains a working piston and a working piston rod extending from an end of the chamber. The pressure chamber contains a rear outer piston having a cylindrical recess and a central bore. An inner piston is located in the cylindrical recess and has a main piston rod extending through the bore, a bore in a separator separating the chambers, and is affixed to the working piston, so as to move together. The main rod has a longitudinal passage which supplies air from the pressure chamber to the back of the working piston under certain conditions. After the working piston rod contacts a workpiece, force of air pressure on all three pistons act on the working piston rod. An air return passage is provided to return the various components to their initial position after the working operation is complete.

Abstract: A semi-active suspension system having a linear actuator operatively connected between a sprung mass and an unsprung mass of the vehicle for each corner of the vehicle. An accumulator connected to the actuator through an electrically controlled valve. An actuatable fluid RAM is in fluid communication with the accumulator for controlling fluid pressure in the accumulator. A hydraulic ram driver is operatively connected to the RAM. A sensor senses force inputs to the vehicle. A controller controls (i) the ram driver for pressurizing the accumulator to a desired fluid pressure, and (ii) the electrically controlled valve in response to sensed force input so as to effect a fluid pressure change in the actuator. Each fluid RAM includes a hydraulic motor having a housing and a piston slidably mounted in the housing.

Abstract: A pneumatic driver is disclosed. The pneumatic driver includes a frame and a shaft movable between an extended driving position and a retracted position relative to the frame. A first inflatable air bladder is supported by the frame. The first inflatable air bladder is operatively connected to the shaft so that when the first air bladder is inflated, the shaft is moved into an extended driving position. A second inflatable air bladder is supported by the frame and operatively connected to the shaft. When the second air bladder is inflated, the shaft is moved to a retracted position. A valve manifold operatively connects first and second air bladders for controlling inflation and deflation of the air bladders. The frame includes longitudinal guide rods and transverse frame members fixed to the guide rods. A shaft support member having the shaft mounted thereto is slidably mounted on the guiderods. Support rods are mounted to the shaft support member by bolts received in orifices to provide a clearance fit.

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: A double-acting actuator includes a first tubular body made of an elastic material, a first reinforcing braided structure surrounding the first tubular body, a second tubular body made of an elastic material surrounding the first reinforcing braided structure to form a space outwardly thereof, and a second reinforcing braided structure surrounding the second tubular body. The actuator further includes closure members for closing and joining ends of the first and second tubular bodies and reinforcing braided structures, and guiding device for permitting axial movements of the first and second tubular bodies but restraining lateral movements thereof. The first and second reinforcing braided structures are so constructed that initial braided angles thereof permit of the first braided structure elongating and permit of the second braided structure contracting when the pressurized fluid is supplied into the first and second tubular bodies.

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

Abstract: A deep well pump for positioning in a bottom hole assembly and having at least one fluid pump and at least two fluid powered motors with the pump and motor pistons carried in alignment on the piston rod. The pump includes passages for delivering a power fluid to one end of each of the motor cylinders and for receiving exhaust fluid from the other end of the motor cylinders, and a valve for reversing this operation. A first sleeve is positioned around the first motor cylinder defining a power fluid path from one end of the first cylinder to one end of the second cylinder, a second sleeve is positioned around the first sleeve defining an exhaust fluid path from the other end of the first motor cylinder, and a third sleeve is positioned around the second motor cylinder defining an exhaust fluid path from the other end of the second motor cylinder, with the first and second exhaust fluid paths interconnected.

Abstract: A hydraulic actuator is formed by a first element incorporating a plurality of different sized piston cavities by a first set of piston elements which cooperate with a second set of piston elements and piston cavities respectively formed on a second element. Each of the cavities is selectively connected to a source of high pressure fluid or a source of low pressure fluid. The second element forms a driven piston in a cylinder formed by an extension of the first element. A second cylinder of a cross sectional area different from the first cylinder is hydrulically connected to the first cylinder and incorporates a second piston at its end remote from the first piston. The force or distance travelled by the second piston is correlated with that of the first or driven piston in a ratio equal to the ratio of the cross sectional areas of the two pistons. Preferably the second piston will be a double acting piston so that pressure may be applied to force the driven piston and first element together.