Abstract: An injection well system is disclosed. The injection well system includes an injection wellhead having a lower master ball valve disposed at a first lower portion of the injection wellhead, an injection wellbore connected to the first lower portion of the injection wellhead, and a nonmetallic check valve disposed below the Earth's surface and at a pre-determined location of the injection wellbore, where the nonmetallic check valve, when closed, isolates the injection wellhead from a second lower portion of the injection wellbore.

Abstract: A single-way damping plunger cylinder includes a cylinder body (3), a piston rod (4), a piston (6) and a sleeve (2), the piston (6) dividing the cylinder body (3) into a first cylinder chamber (31) and a second cylinder chamber (32), a first end of the first oil passage (40) being communicated with the first cylinder chamber (31) via the second oil passage (41) and a second end of the first oil passage (40) being communicated with the second cylinder chamber (32), the valve (5) movably disposed in the second oil passage (41) to open or close a direct communication of the first and second oil passages (40,41); a damping oil passage (50) defined in the valve (5) to communicate the first oil passage (40) with the second oil passage (41). A forklift is also provided.

Abstract: A piston-in-piston hydraulic unit is disclosed that utilises an elastic volume to store and release energy with each stroke by varying the hydraulic fluid volumes in and out of the hydraulic unit.

Abstract: To prevent effects of small amplitude oscillations caused by pressure fluctuation, eccentric attachment of a cancel plate and biased load application of a return spring, and to achieve a long service life of the inner peripheral seal portion, a BPS (1) with a piston member (20) moving in an axial direction inside a cylinder (10) and defining a compression chamber (M) together with the cylinder (10) and a cancel plate (30) opposing to a bottom portion (11) of the cylinder (10) beyond the piston member (20) is provided with an inner peripheral seal portion (50) with a seal lip (52) slidably contacting an inner peripheral tube portion (13) of the cylinder (10) and a fitting portion (53) fitted to the inner peripheral tube portion (13) in an inner peripheral end portion (35) of the cancel plate (30).

Abstract: A linear drive unit (1) possesses a first principal body (2) with a U-like section part (4) and furthermore a second principal body (3) with a drive housing (7). Using at least one drive means the two principal bodies (and 3) may be driven to perform a linear relative movement. The section part (4) straddles the drive housing (7), its longitudinal limbs (5a and 5b) being opposite to the side faces (13a and 13b) of the drive housing (7) with the intermediate placement of linear guide means. The section part (4) comprises two section elements (23a and 23b) each having one of the limbs (5a and 5b), such section elements being firmly joined together and being placed opposite to each other alongside each other setting the guide play of the linear drive means.

Abstract: This invention relates to a linear path slide (10) with a slide (26) which is arranged slidingly movable in a housing (12) along a sliding guide (20) and safe against torsion and with a hydraulic driving gear (40) integrated into the slide (26) for a shifting movement of the slide (26), whereby a working piston of the hydraulic driving gear (40) is configured with at least two stages, whereby each stage of the working piston forms a partial hydraulic driving gear (40′, 40″) of the hydraulic driving gear (40) so that higher actuation forces can thus be realized.

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: An actuator combining mechanical and hydraulic forces includes a cylindrical body and a piston that can slide relative to the cylindrical body. The piston and the cylindrical body are connected by a mechanical system for transmitting mechanical power that constitutes a device that permanently controls the position of the actuator, a permanent locking device, and a safety device. The means for transmitting hydraulic power constitute a load compensator device. The two means for transmitting power operate in parallel. Position control using the drive system at reduced power can be synchronized in a simple way for a plurality of actuators.

Abstract: A hydraulic receiver for clutch control having a fixed part including an internal guide tube and a concentric external body defining a blind annular cavity supplied with fluid. A piston carrying a drive element for engaging a declutching device is mounted inside the blind annular cavity.

Abstract: The invention concerns a hydraulic, in particular clutching, actuator for receiving control data from a hydraulic circuit in the form of pressure variations. The concentric-type actuator (8) for hydraulic control comprises a fixed part (9) consisting of an external body (21) and a guide tube (22), both cylindrical and coaxial, and a piston (11) mounted sliding coaxially to the fixed part (9) and defining therein a chamber with variable volume (13) designed to be connected to the hydraulic control hydraulic transmitter, the external body (21) comprises on its internal face (35) a groove wherein is inserted a radial edge (31) with which the guide tube (22) is provided at one of its ends and which partially constitutes the variable volume chamber (13) bottom.

Abstract: A hydraulic clutch release mechanism, particularly for use in the power train of a motor vehicle, employs a circular piston which is reciprocable in a plenum chamber between a cylindrical housing and a guide centrally located within the housing. One end portion of the piston is form-lockingly connected with a plastic seal at the plenum chamber. Such form-locking connection is provided adjacent one of two lips forming part of the seal. The one lip engages the external surface of the guide and the other lip engages the internal surface of the housing and is adjacent another form-locking connection established between the seal and an annular plastic or metallic retainer which is affixed to the piston with limited axial play. The other end portion of the piston is operatively connected with a clutch, e.g., by way of a release bearing.

Abstract: A hydraulically operated central release unit for a motor vehicle clutch is designed as a slave cylinder that is arranged inside a clutch housing. The central release unit includes a housing in which a ring piston is movably guided. The ring piston has a groove ring seal with lips sealingly contacting the sealing tracks. To reduce the wear on the sealing lips and to avoid squeaking noises of the groove ring seal, the surfaces of the sealing tracks are provided with micro cavities.

Abstract: The present invention relates to an improved structure of a piston for air-filing device by making use of air pressure formed as a result of the reciprocation action of piston within the cylinder to urge an air-tightness disc mounted at the top of the piston to close rapidly and to open instantaneously. At the simultaneous reciprocation action of the piston, the cylinder is provided with a rapid flowing in of air without passing through an air-inlet valve and the air is compressible. This facilitates the speed of compression of the entry air, and avoids the installation of the air-inlet valve.

Abstract: A solar-powered reciprocating pump for submersible use in a well, such as a water well. The pump has a pumping section with a plunger therein. The pump also has a drive section with a rotating output shaft and a transmission section which converts the rotating output of the shaft into reciprocating motion of the plunger. In one embodiment, the transmission comprises a gear train. In a second embodiment, the transmission comprises a ball screw which is actuated by a reversible motor. In a third embodiment, the transmission comprises a reversible ball screw which provides reciprocating action in response to rotation of a shaft in a single direction. The pumping section comprises an outer case portion with a cylinder disposed therein such that an annular volume is defined therebetween. A system of flow passageways and inlet and outlet valves provide for pumping liquid into and out of the pump in response to movement of the plunger in both upward and downward directions.

Abstract: A cylinder device includes a casing with a pair of fluid inlet/outlet ports defined therein, a base plate, a piston fixed to the base plate, a cylinder, and a top plate. The cylinder device also has first, second, and third cylinder chambers defined in the cylinder between the base plate, the piston, and the top plate, a first fluid passage and a second fluid passage through which one of the fluid inlet/outlet ports communicates with the first and third cylinder chambers, and a third fluid passage and a fourth fluid passage through which the other fluid inlet/outlet port communicates with the second cylinder chamber.

Abstract: An accumulator piston for an automatic transmission. The piston comprises two components, the first and second being cup elements welded together with their closed ends in abutting relation. The lower cup includes a curled back portion with a radial flange having an axially extending bi-directional oil seal thereon, and spaced apart recesses in the curled back portion to permit oil to flow therein. The upper cup includes a radial flange of reduced diameter compared to the lower cup flange. The flange also has a lip seal thereon. The piston is spring-loaded and moves up and down in a bore and counterbore in response to fluid flow on either side of the piston to absorb shifting shocks.

Abstract: A slave cylinder for the operation of a friction clutch, especially in motor vehicles, with a housing, an inner portion, an annular or cylindrical piston which annular piston is positioned between the housing and the inner portion, a clutch release sleeve or clutch throwout sleeve or coupling socket joint which clutch release sleeve is in contact with the annular piston and can be axially displaced with respect to the housing, as well as a spring or pressure spring or compression spring which is supported by both the clutch release sleeve and the housing, and radial shoulders or steps or reliefs provided at the clutch release sleeve and at the housing to secure against torsion. The pressure spring may be characterized as a sinuous spring or zig-zag or no-sag spring. The ends of the pressure spring are positioned to make contact at the ends of the shoulders which shoulders act in the opposite direction to secure against torsion.

Abstract: A linear thruster is disclosed in which a load beam is linearly moved by fluid power relative to a guide beam and a piston. The beams are multisided in cross-section to substantially increase the linear bearing area between the bodies and, thereby, substantially increase the strength of the linear thruster against side forces as well as moments to which the linear thruster might subjected. Internal positioning of the components and energy transmission are maximized and the stroke may be variably adjusted.

Abstract: A piston seal has formed on one side of the piston body upon which oil pressure works are a tapered surface portion which extends in a direction away from a piston sliding wall and a parallel surface portion. A lip-like seal is formed of a seal base portion which is, in cross section, approximately triangular to fill a space defined between the tapered surface portion and the piston sliding wall, and a lip portion which is formed integrally with the seal base portion. Q indicates the exertion line of a force which presses the lip portion against the piston sliding wall. T is a normal line which extends from the tapered surface portion towards the piston sliding wall. In order to prevent the lines Q and T from intersecting with each other within the bore, the seal base portion is arranged to lie apart from the lip portion in relation to the axial direction of the bore.

Abstract: The invention concerns a fluid pressure ram having a fixed cylindrical control chamber defined radially by inner and outer partitions, in which one axial end of the chamber is closed off by a piston which has a cylindrical housing and in which, in the retracted position of the piston, the inner partition of the chamber is received in the housing. The piston, in the protruding position, is fully disengaged axially from the fixed chamber. Two cylindrical shells provided axially in line with the chamber are provided when the piston is in the retracted position. The shells are able to slide axially with respect to the piston and with respect to the chamber so as to define, in the protruding position of the piston, an intermediate annular chamber which axially extends the fixed chamber and which is closed axially by the piston.

Abstract: An actuator, particularly for the operation of a vehicle clutch in which an annular piston (10) slides between cylinder walls (11, 12) to define an annular working chamber (20). A sealing means (15) seals the piston to the cylinder walls and an overflow chamber (26, 27) retains any fluid which leaks past the sealing means from the working chamber. A return means (28) is also provided for returning fluid from the overflow chamber when the piston is not undertaking a working stroke.

Abstract: An actuator for a turbocharger includes a housing having a chamber therein, a piston assembly having a rod and a piston secured to a rod for axial movement therewith, a spring operatively interposed between the piston and the housing for urging the piston upward within the chamber. A hollow retainer is mounted to the housing and extends into the chamber alongside the piston. The retainer has a housed portion having a generally cupped shape with a cavity therein for receiving a pressure signal from the turbocharger. The retainer has axially spaced first and second peripheral protrusions thereon. An O-ring mounts on the retainer between the first and second protrusions and in engagement with the retainer and piston simultaneously. The O-ring rolls between the first and second protrusions in response to the pressure signal and the resulting relative axial movement between the retainer and piston, thus decreasing hysteresis in the actuator.

Abstract: A fluid powered rotary actuator having a body with first and second ends. The body has a generally cylindrical interior sidewall with a grooved, inwardly facing circumferential portion. The body is adapted for coupling to a first external member. A drive member extends generally coaxially within the body and is supported for rotation relative thereto. The drive member has an end flange positioned toward the body first end adapted for coupling to a second external member, and a shaft rigidly attached to the end flange. The shaft has a grooved, outwardly facing circumferential sidewall portion positioned within the body toward the body second end and a smooth, outwardly facing circumferential sidewall portion positioned within the body between the end flange and the shaft groove sidewall portion.

Abstract: An actuating unit for a hydraulic brake system for automotive vehicles includes a vacuum brake power booster and a master brake cylinder. To transmit the reaction forces, developing during actuation in the master brake cylinder, to a vehicle body wall which carries the actuating unit, a centrally positioned force-transmitting element is provided, which is arranged between the master brake cylinder and the vehicle body wall in terms of effect. The force-transmitting element is formed of a continuous bolt which extends in an axial direction through the control housing of the vacuum brake power booster.

Abstract: A piston and seal assembly that has a rigid core with an elastomeric seal bonded thereto. The core has an annular outer cylindrical edge, a forwardly facing surface and a rearwardly facing surface. The elastomeric member is bonded to the core so as to encase the annular cylindrical edge. The elastomeric member extends outboard of the rearwardly facing surface of the core to provide a sealing lip. An annular concave surface merges with an annular convex surface located axially rearwardly of the rearward facing surface on the core. A radially outwardly directed surface on the lip portion merges tangentially with the convex surface.

Abstract: In a clutch release cylinder device, comprising an annular cylinder defining an annular recess, an annular piston slidably received in the annular recess; and an annular clutch release bearing assembly including a release bearing, the annular cylinder is constructed by a pair of cylinder members each formed by drawing sheet metal, and provided with a flange and a tubular portion, the tubular portion of one of the cylinder members being larger than that of the tubular portion of the other cylinder member, the annular recess being defined between the tubular portions which are coaxially nested with each other. Because the cylinder members may be made of metallic material, such as steel and other materials of high rigidity and mechanical strength, a sufficient rigidity and mechanical strength can be ensured with a substantially smaller wall thickness as compared to a cylinder formed by a molded plastic member, and substantially more economically as compared with a cylinder formed by machining a metallic block.

Abstract: A hydraulic actuator including a single cylinder body which defined therein a pressure chamber in which a first piston with a piston rod and a second piston with a piston rod are independently movably inserted, a first working member secured to the first piston rod, a second working member secured to the second piston rod, and pressurized fluid inlet and outlet ports provided in the cylinder body to be connected to the pressure chamber.

Abstract: The invention relates to a fluid-actuable releaser in which an annular piston (6) is guided in a casing (3) which is provided with a sleeve (10) for guiding the annular piston (6) radially internally and for sealing purposes, the sleeve (10) being axially fixed by partial plastic deformation after insertion into the casing (3) with its external diameter in a bore (16) in the casing (3).

Abstract: An intensifier cylinder including a body structure defining a first bore, a first piston structure including a piston mounted in the first bore and a piston rod secured to the piston and extending at its forward end through an end wall of the body structure, a second bore defined in the body structure, a second piston structure including a second piston mounted in the second bore and a second piston rod secured by the second piston and movable at its forward end into the first bore upon stroking of the second piston in response to the introduction of pressurized gas into the second bore to seal off and act upon hydraulic fluid in the first bore to produce an intensified force on the first piston structure.

Abstract: A master cylinder includes a second piston that is provided with a hollow portion. The hollow portion includes a yoke portion for receiving an end of the second return spring, a cylindrical portion having a diameter that is larger than the diameter of the second return spring, and a tapered portion located at the open end of the hollow portion. The second return spring is disposed within the yoke portion so that the second return spring is coaxially arranged with respect to the second piston. Thus, although the second return spring is capable of moving rapidly to and fro within the hollow portion, the construction of the second piston and the arrangement of the second return spring within the hollow portion of the second piston helps avoid interference between the second piston and the second return spring. Thus, unpleasant noise can be reduced or eliminated. Moreover, small particles that would normally result when the second return spring scratches the second piston are not as likely to arise.

Abstract: A slave cylinder of the annular cylinder type is proposed, whereof the annular piston (45) able to slide axially between an outer cylinder wall (29) and an inner cylinder wall (33) is sealed by a grooved sealing ring (53) with respect to the pressure chamber (37). In order to be able to evacuate by means of a suction pump a hydraulic actuating system for a motor vehicle friction clutch, constructed using a slave cylinder of this type, before filling with hydraulic fluid, means are provided on the annular cylinder or in addition to the sealing lips (57) on the grooved sealing ring, which increase the sealing action of the sealing lips (57) when applying a vacuum to the hydraulic pressure chamber (37). The said means may be conical surfaces (61, 63) on the cylinder walls or a conical ring engaging in an annular groove (59) of the sealing ring (53). Additional sealing beads having a cross-sectional contour in the shape of a circular sector may be formed if necessary on the grooved sealing ring.

Abstract: A hydra-jack screw apparatus is provided for exerting a force against an object, for adjusting the magnitude of the force exerted against the object, and for providing a visual indication of the magnitude of the force exerted against the object. The apparatus is comprised of a base member housing a piston chamber, a jack screw extending from the bottom of the base member, a fluid pressure gauge mounted on the base member, and a pair of pistons received in the piston chamber for reciprocating movement. One of the pistons has a piston rod that extends through a center bore of the jack screw and engages against an object against which a force is to be applied. The second piston has a piston rod that extends from the piston chamber of the base member and is attached to a manual forced adjusting knob. A volume of fluid is contained in the piston chamber between the first and second pistons, and as the manual knob is turned, the pressure of the volume of fluid is adjustably increased or decreased.

Abstract: Piston sealing and dampening device in a pressurized-fluid cylinder, where a piston (3) has a central recess (3a) facing towards a cylinder end cap (1a) and disposed such that when the piston is in the vicinity of its end position, said recess accommodates a sleeve portion (5) provided with an internal pressurized-fluid connection (6) and projecting from the cylinder end cap. An integrated sealing ring (10) seals against the outside of the sleeve portion (5) with an inner sealing ring lip (10e) and against the inside of the cylinder tube (2) with an outer sealing ring lip (10c).

Abstract: A piston assembly comprising a primary piston and a co-centric secondary piston. The pistons are received within a housing for reciprocating movement therein and relative to each other. The housing and the pistons are arranged for operating pressure to be applied to the secondary piston so as to drive both pistons within the housing. The secondary piston is provided with means enabling the operating pressure to be equalized across the secondary piston and at least one bypass passage extends through the secondary piston. The arrangement is such that upon completion of the stroke of the pistons pressure equalization occurs across the secondary piston which causes the pistons to separate. The bypass passage becomes fully operable subsequent to pressure equalization, whereby a fast return stroke is achieved.

Abstract: A direct drive type rotation dividing table includes a dividing table mounted on an output shaft of a rotor which is accommodated in a housing together with a stator. A clamp mechanism for maintaining the dividing table at a stopped position includes a cylinder slidably disposed in the housing in an axial direction and having a radially extending plane portion and a friction surface adapted to contact the output shaft, an elastic member having one end connected to the housing and urging the friction surface of the cylinder to move away from the output shaft, and a piston having an elastically deformable thin plane portion opposing the plane portion of the cylinder and having one side fixed to the housing and the other free end slidable on the inner surface of the slider. The piston has a friction surface which is adapted to contact a backside of the dividing table.

Abstract: This hydraulic actuator has a drive volume (11) pressurized by extreme-pressure oil. The oil pressure is converted into a valve movement by a drive piston (10). A spring element acts upon the drive piston (10) in a manner opposing the oil pressure. The actuator is to be constructed such that extreme-pressure oil escaping from the drive volume (11) cannot cause any consequential damage. This is achieved in that the drive volume (11) is completely surrounded by a safety volume (3, 7) filled with low-pressure oil.

Abstract: An actuator including a cylinder having a longitudinal bore, a piston slidably and sealingly inserted into the cylinder, and a lock mechanism for temporarily locking the piston, the cylinder including a cylinder body having the longitudinal bore, a cylinder formed at a front end of the cylinder body and accommodating the lock mechanism, and a front wall connected to the cylinder head at a position opposite to the front end of the cylinder body and having a hole formed therein, the piston including a piston head slidably and sealingly inserted into the cylinder bore, the piston rod projecting from the piston head and slidably insertable into the hole of the front wall, a key groove formed on the piston rod at a position near the piston head, and a longitudinal hole formed within the piston head and the piston rod, wherein the diameter of the piston rod decreases from a backward position adjacent to the key groove to a forward position spaced from the piston head.

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.

Abstract: A hydraulic actuator is formed by an assembly including a first element, a cylinder, a body section and a chamber. The first element is provided with a first set of a plurality of different sized piston cavities and piston elements which cooperate with a second set of piston elements and piston cavities respectively formed on a second element. The second element forms a piston in cylinder. The body sides incorporates, preferably in symmetrical relationship around the axis, of the assembly a plurality of valves, one valve for each of the pairs of cooperating pistons and cavities. A piston divides the chamber into a high pressure reservoir and a low pressure reservoir with the piston being urged toward the high pressure reservoir to maintain a difference in pressure between the high and low pressure reservoirs.

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: The vacuum servomotor comprises a main casing (12) divided sealingly on the inside into first and second chambers (10, 20) by a flexible membrane (9) bearing on a rigid disk (7) integral with an activating piston (3). The first chamber (10) is subjected to a low pressure, while the second chamber (20) is subjected either to this low pressure or to a higher pressure. An auxiliary casing (25) is integral with the rigid disk (7) and projects into the first chamber (10), an auxiliary piston (27) sealingly dividing the auxiliarly casing (25) on the inside into third and fourth chambers (30, 40), the third chamber (30) being closed by the rigid disk (7), the auxiliary piston (27) being mounted stationary relative to the main casing (12).

Abstract: The hydraulic clutch actuator for a motor vehicle of the concentric type in which the actuator is mounted concentrically around the transmission input shaft of the vehicle within the housing of the clutch. The actuator includes a housing structure defining a central quill shaft surrounding the input shaft of the vehicle and slidably supporting the hub portion of the bearing carrier and further defines an annular piston bore spaced radially outwardly from the quill shaft to define an annular bore between the piston bore and the quill shaft into which the rear end of the hub portion of the bearing carrier may move during the operation of the actuator so as to provide overlap as between the annular piston and the bearing carrier and minimize the axial dimension of the actuator. The preload spring is also positioned in the annular bore between the quill shaft and the piston bore so as to further optimize the compact packaging of the actuator.

Abstract: A multistage cylinder actuator comprising a center cylinder unit and annular auxiliary cylinder units which are concentrically located around the center cylinder and which are removably attached to a common plate so as to independently operate.

Abstract: An actuating piston assembly (10, 110) for a torque transmitting device (11). The actuating piston assembly (10, 110) has a seal subassembly (35, 135) with a supporting annulus (36, 136) and a seal member (38, 138). The seal member (38, 138) is preferably bonded to the supporting annulus (36, 136). A generally radially oriented first wiping lip (55, 155) extends outwardly with respect to said seal subassembly (35, 135), and a generally radially oriented second wiping lip (56, 156) extends inwardly with respect to said seal subassembly (35, 135). A plurality of circumferentially spaced bores (41, 141) penetrate the supporting annulus (36, 136) and the seal member (38, 138). A plurality of dowel-like connecting rods (42, 142) are presented from at least selected bores (41 and 58 or 141 and 158).

Abstract: A fluid pressure operated positioning apparatus has a cylinder (1), formed as an annular cylinder, with an outer cylinder wall (2) and an inner cylinder wall (3) coaxial with and spaced apart radially from the outer cylinder wall. In the annular cylinder, a piston arrangement including at least one ring piston (8) is slidably guided, its ring piston surrounding the inner cylinder wall and being connected to at least one elongated force transfer element (22) that is extended in a sealed manner out of the annular cylinder.

Abstract: A piston engine having a reciprocating piston, which is journalled in a radial direction with respect to the direction of translation by means of at least one dynamic groove bearing located within the piston and is separated from a compression space by an annular sealing gap at an outer surface of the piston. The piston engine is suitable for use in compressors and cryo-coolers, more particularly for cooling of computer processors.

Abstract: An actuating piston assembly (10) for torque transmitting systems (11). The torque transmitting system (11) is encased within a housing member (12), and a mounting annulus (40) is presented from the housing member (12). The mounting annulus (40) has a radially outer, cylindrical surface (41) and a radially inner, cylindrical surface (42), the two surfaces (41 and 42) being preferably concentric. A seal retainer (45) is carried on the mounting annulus (40), and the seal retainer (45) has a substantially planar web portion (46). Outer and inner rims (50 and 51) are presented from the web portion (46) and frictionally engage the corresponding outer and inner surfaces (41 and 42) on the mounting annulus (40) to secure the seal retainer (45) thereto. A plurality of circumferentially spaced outer blocking flanges (52) extend radially outwardly from the outer rim (50), and a plurality of circumferentially spaced inner blocking flanges (53) extend radially inwardly from the inner rim (51).

Abstract: A swash plate type hydraulic pumping assembly (10) including a plurality of pistons (28) axially reciprocated in individual chambers (22) of a rotor (20). Each piston (28) includes a hollowed central cavity (30) supporting a compression spring (54) which urges the piston (28) out of the chamber (22) and toward a camming surface (64) of the swash plate (60). A tube (42) is disposed in the chamber (22) adjacent a hydraulic fluid exhaust port (24) and forms the only flow route for fluid entering or exiting the chamber (22). A top surface (34) in the cavity (30) of the piston (28) is spaced from the exhaust port (24) and collects gas inclusions trapped in the fluid during operation. When the piston (28) is moved in the chamber (22) to a fully compressed position, the top spaced surface (34) is very close to the tube (42) allowing the trapped gas inclusions to be swept away from the top spaced surface (34) and out of the pump assembly (10).

Abstract: A hydraulic cylinder apparatus is used by connecting an external pressure source with extension and contraction-side liquid chambers defined by a cylinder, a piston sliding in the cylinder and a piston rod integral with the piston. The apparatus includes seal members provided with the extension and contraction-side liquid chambers and formed to enable liquid to leak through clearances between the seal members and the parts disposed opposite to the seal members. Liquid leaked from the extension and contraction-side liquid chambers is received by a receiving chamber which is formed so as to change its volume with the movement of the piston rod.

Abstract: A free piston to be slidably inserted in the cylinder of an electromagnetic reciprocating compressor. The piston has a partition wall dividing the inner space of the cylinder into chambers, and a rod connected to the partition wall. The partition wall has an air hole. A valve member is attached to the front surface of the partition wall, and usually closes the air hole of the partition wall. The rod extends rearwardly from the rear-end surface of the partition wall. The rod has a substantially conical hole which extends rearwardly from the front-end surface of the partition wall. The piston further comprises a retainer cap closing the opening of the substantially conical hole and holding the valve member in an openable condition.