Abstract: A piston for a needleless valve system comprising a head portion configured to be disposed in the needleless valve system and controlling fluid flow through the needleless valve system. The head portion comprising a continuous top surface, and an opening disposed proximate the continuous top surface, wherein the continuous top surface is non-planar when the opening is in an open position.

Abstract: A reciprocating compressor including an oscillation-type piston mechanism is provided with a piston ring which is mounted in a piston ring groove to seal a space between a piston and a cylinder. A ring groove other than the piston ring groove is provided at an outer periphery of the piston on a side away from the piston ring groove and closer to a crank shaft. A guide ring, which is inhibited from radial movement and shaped like a skirt opened toward the crank shaft, is mounted in the ring groove. Thus, the oscillation-type reciprocating compressor is adapted to maintain long-term durability even under high-pressure compression condition and to prevent heat propagation to a large end portion.

Abstract: A bellows is provided for fluid storage and displacement used in precise fluid indication in a capillary tube. The bellows is made of a housing made of flexible, watertight material. The housing is made up of an upper portion, a lower portion, and an outer accordion formed portion. The accordion formed portion has a length/and is sealingly connected along a periphery between the upper and lower portions. At least one entry/exit port is formed on at least one of the portions thereof. At least one of the upper and lower portions extends from a periphery of the accordion formed portion substantially within the housing so as to reduce the storage volume.

Abstract: A fluid control device for use in a high pressure fluid system, the device including a device body with a cavity and a high pressure circuit, a plunger positioned for reciprocal movement in the cavity, and a leakage reduction cap mounted to the plunger for reducing fluid leakage flow. In one implementation, the leakage reduction cap includes a flexible portion positioned between the device body and the plunger, and defining an annular clearance gap between the leakage reduction cap and the device body. The flexible portion of the leakage reduction cap resiliently flexes radially outwardly in response to fluid pressure forces to reduce the annular clearance gap so as to minimize fluid leakage flow through the annular clearance gap.

Abstract: A piston assembly of a reciprocating pump includes a core having a throughbore, a first annular shoulder, a first radial surface that extends from an upper end of the core to a first annular shoulder, and an elastomeric element disposed about the core, where the elastomeric element has a body including a semi-supported section having a first outer radial surface.

Abstract: A sealing member for a piston slidably disposed within the cylinder bore of a hydraulic system includes a seal body having an outer sealing surface arranged to contact the cylinder bore and a glide ring at least partially disposed within the outer sealing surface of the seal body. The glide ring includes an outer surface and the outer sealing surface of the seal body includes at least one seal lip projecting beyond the outer surface of the glide ring.

Abstract: A piston chamber combination comprising a container type piston, communicating with an enclosed space, said enclosed space having an at least substantially constant volume.

Abstract: A piston for a cylinder, in particular for a hydraulic piston storage or a hydraulic cylinder having a multipart configuration with two piston parts (11) made of material nontransformable under pressure, subjected to the pressure prevailing in the cylinder, which piston parts comprise, between them, a radially expandable sealing member, with the piston parts (11) arranged such that the pressure in the cylinder axially acting on them effects an increase in the pressure of partial areas of the sealing member against the cylinder wall, wherein the sealing member is made of a support part (12) consisting of the deformable material for a piston seal (20) and at least one piston seal (20) inserted in a groove (19) formed on an outer circumferential surface of the support part (12), and that the cylindrical support part (12) has tapers (13) on both sides with across-piece (14) remaining between them for accepting the two engaging piston parts (11) in such a way that the support part (12) overlaps the piston parts (1

Abstract: In a rocking piston type compressor, a piston rod 11 is rockingly slidable within a cylinder 10. The compressor is provided with a lip ring 20 and an expansion member 30. The lip ring 20 is configured to seal between the cylinder 10 and piston rod 11. The lip ring 20 is provided on a leading end portion 13 of the piston rod 11 and includes a bottom portion 21 in a circular plate shape and a lip portion 22 extending from an entire peripheral edge of the bottom portion 21 to an upper side in a height direction. The expansion member 30 is provided on an inside of the lip portion 22 and configured to outwardly expand the lip portion 22 at a side of an upper portion in the height direction of the lip portion.

Abstract: A piston for an automatic transmission includes a cylindrical portion formed of a steel material and an elastomer bonded thereto. The elastomer includes an ethylene-acrylic polymer, a filler, and a hexamethylene diamine curing agent. The elastomer is compression or injection molded to the metal cylindrical portion. During the molding step, the elastomer is cured and achieves a cross-link density, strength, and other physical properties sufficient for use in an automatic transmission. Thus, the piston is formed without a post curing step. The piston provides a lower wear rate and a higher life expectancy than pistons formed with a post curing step.

Abstract: A linear compressor having an electromagnet; an oscillating body that moves back and forth in the alternating field of the electromagnet; a piston that is connected to the oscillating body and that reciprocates in a cylinder and delineates a pump chamber; and an elastically deformable plate that forms at least one of the end faces of the pump chamber.

Abstract: A sealing arrangement for two relatively movable first and second parts and including a sealing ring positioned in a groove on one of the parts for sealing contact against the other one of the parts, so as to separate a first side of the sealing ring from a second side of the sealing ring, wherein the sealing ring is positioned in a sealing ring seat formed as a groove in the circumference of one of the parts, including liquid supply means for supplying liquid under pressure to the second side of the sealing ring, and means for balancing the pressure of the supplied liquid in the region of the sealing ring, whereby forces on the sealing ring resulting from the pressure prevailing on the first side of the sealing ring are counteracted and balanced in such a way that in operation the sealing ring is essentially free-floating in the groove. The invention also concerns a reciprocating piston device including such a sealing arrangement.

Abstract: A pumping apparatus for a high performance liquid chromatography system (350) is disclosed. The pumping apparatus comprises a piston (1) for reciprocation in a pump working chamber (3) to compress liquid in the pump working chamber (3) to a high pressure at which compressibility of the liquid becomes noticeable. At least one of the piston (1) and the pump working chamber (3) is at least partially coated with or comprised of silicon carbide.

Abstract: An oil-less/oil-free air brake compressor comprising a bore, a piston positioned for reciprocating in the bore, the piston having an annular recess and a rigid polymeric piston ring received within the annular recess, the piston ring having a predetermined non-circular profile in the free state.

Abstract: A piston for a fluid operated power cylinder has two mutually coaxial sealing lips axially extending away from each other and being able to radially yield, for sealing engagement with the piston running face of the power cylinder and adjacent to at least one piston end side an elastic buffer body serving for shock absorbing in the end of stroke position of the piston, said body having an impact face facing away from the piston. At least at one piston end face the sealing lip itself constitutes the buffer body and has the impact face at its end, groove-like recesses being formed on the inner periphery of the sealing lip with a distribution in the peripheral direction, such recesses opening toward said impact face.

Abstract: A piston and ring assembly for a compressor that may be used in a vehicle air conditioning system. The assembly comprises a piston and a ring located within a cylinder bore. The ring has a frustoconical shape and the piston has a complementary frustoconical groove. The ring is a parallelogram in cross-section.

Abstract: Preferred rod/piston assemblies (50, 50?, 150) comprise unitary rod members (52, 52?, 152) and compression rings (54, 54?, 154). In accordance with one preferred embodiment (50), the unitary rod member (52) comprises a connecting rod portion (60), a lower bezel portion (62) and a knob portion (66). The lower bezel portion (62) and the compression ring (54) define facing surfaces (82, 106) along which the compression ring (54) is secured to the unitary rod member (52). In accordance with a preferred method of manufacture, one or both of the facing surfaces (82, 106) are chemically treated to promote coupling of the compression (54) ring to the lower bezel portion (62). The unitary rod member (52) and the compression ring (54) are positioned in the mold or press with the compression ring (54) fitted over the knob portion (66) of the unitary rod member. Elevated temperature and pressure are applied to secure the compression ring (54) to the lower bezel portion (62).

Abstract: A piston packing has a mounting surface and a seal surface. The seal surface and the mounting surface are fitted with a head and an annular groove portion, respectively, of a piston.

Abstract: For the purpose of providing a thin pump designed to decrease the number of parts, the pump is provided with a rectangular parallelepiped cylinder (3) and a piston located inside of the cylinder, wherein the piston (4) reciprocates and oscillates in the cylinder (3) to vary capacity of the pump chamber (12) and to make the intake port (5) and the outlet port (6) open alternately, so that fluid is sucked from the intake port (5) into the pump chamber (12), compressed and discharged from the outlet port (6).

Abstract: A piston or plunger is made by passing an annular sealing member blank around a piston body and by moving it towards a central outer cylindrical surface part of the piston body defined between first and second circular edges. The sealing member blank is deformed into tight engagement with the central outer cylindrical surface part and into grooves or depressions formed therein. In this manner, a tubular sealing member, which extends axially along the central outer surface part, and which has opposite first and second ends extending beyond the first and second circular edges, respectively, is formed. Thereby both of these opposite end portions of the tubular sealing member may function as sealing lips.

Abstract: Pump apparatus according to the present invention may comprise a pump body having a bore therein and a piston mounted within the bore so that the piston may be reciprocated within the bore between first and second positions. A sleeve seal assembly mounted to the pump body contacts the piston as the piston moves between the first and second positions. A piston seal assembly mounted to the piston contacts the bore in the pump body and is located on the piston so that the piston seal assembly does not contact the sleeve seal assembly as the piston is reciprocated between the first and second positions within the bore of the pump body.

Abstract: A hydraulic device includes a housing and a bulkhead disposed in the housing. A pump piston is provided in the housing and has first and second end surfaces with the second end surface of the pump piston and surfaces of the housing and of the bulkhead defining a pumping chamber. The pump piston is constructed and arranged to move within the housing to develop pressure on fluid in the pumping chamber. The first end surface of the pump piston and surfaces of the housing define a pump reservoir chamber. A ram piston is provided in the housing and has first and second end surfaces with the first end surface of the ram piston and surfaces of the housing and of the bulkhead defining a drive chamber. Connecting structure is associated with the bulkhead to communicate the pumping chamber with the drive chamber so that fluid pressure developed in the pumping chamber may be exerted on the first end surface of said ram piston. A barrier is provided in the housing between an end of the housing and the ram piston.

Abstract: An improved structure for a reciprocating internal combustion engine or compressor piston fabricated from carbon-carbon composite materials is disclosed. An integral ring carbon-carbon composite piston, disclosed herein, reduces the need for piston rings and for small clearances by providing a small, flexible, integral component around the piston that allows for variation in clearance due to manufacturing tolerances, distortion due to pressure and thermal loads, and variation in thermal expansion differences between the piston and the cylinder liner.

Abstract: A piston for a fluid power cylinder, which possesses two separate piston parts, which are detachably set together in a joint region axially with a sealing action. Each piston part has a rigid carrying element, which is molded on a holding portion, which in its radially outer region has a lip seal comprising sealing material with rubber-elastic properties and serving for sealing on a piston running face. The respective lip seal and the holding portion associated with same are constituted by components of an integral elastic body comprising a sealing material with rubber-elastic properties. Such elastic body is molded on the respectively associated carrying element. The two elastic bodies are in sealing contact with one another in the joint zone.

Abstract: A piston assembly that is movable back and forth parallel to its axis in a cylindrical housing, comprising a piston-like support part made of a hard material and a guide ring made of a polymer. The guide ring surrounds the support part along a portion of the axial length of the piston. The support part and the guide ring are joined to each other via frictional and/or form locking provided by mating between grooves on the support part and a corresponding number of radial projections on the guide ring. A set of axially spaced apart sealing lips, integrally molded with the guide ring, extends axially beyond the grooves to provide a seal with respect to the cylinder wall.

Abstract: In an elongate tank for transport or for storage in bulk of semisolid and fluid material such as grease and oil. The tank has an outlet at one end thereof for discharging material contained therein and is of generally cylindric internal cross section. It has a generally cylindric piston sized to slide in the tank and adapted to be moved in a direction toward the outlet thereby to force the material in the tank through the outlet. The piston comprises a piston member which carries an annular elastic seal. The seal has an annular crown projecting radially outwardly from the piston member and engageable with the interior surface of the tank.

Abstract: An external slave cylinder particularly suited for use in a hydraulic clutch release system for a motor vehicle. The cylinder includes a cylindrical body defining a bore, a piston slidably mounted in the bore, a seal positioned between the piston and the bore, a pushrod engaging the rear end of the piston and extending out of the bore, and a preload spring. The spring comprises a conical coil spring positioned exteriorly of the bore, bearing at the reduced diameter rear end thereof against the rear end of the pushrod, and bearing at the large diameter front end thereof against the rear end of the body in surrounding relation to the pushrod. The seal has a cup-shaped configuration and fits over a nose portion provided on the front end of the piston. The seal includes a peripheral lip portion sealingly engaging the bore and a base portion closing the area within the peripheral lip portion and seated against the front end of the piston.

Abstract: A piston for a shock absorber as may be used in an automobile comprises a piston body, and a piston ring which covers the outer periphery thereof. One end of the piston ring is formed as a bend, which is received in a first receiving groove formed in the piston body. The first receiving groove comprises opposing end faces which extend in a direction orthogonal to the axis of the piston body, and a bottom surface which connects together the both end faces. The tip of the bend is disposed in abutment against the corner defined by one of the end faces and the bottom surface. As compared with the prior arrangement in which the end face comprising the corner is formed as a tapered surface, the tip of the bend is less likely to be displaced radially outward, thus reducing the possibility that he bend may be disengaged from he first receiving groove.

Abstract: An accumulator piston is formed as a two-piece plastic molding for simplifying its construction and for cost reduction and weight reduction purposes. The piston has a radially stepped construction in which each step includes a radial flange carrying an annular elastomeric sealing element. The sealing elements have deformable, resilient lips which slidably engage the side surfaces of a stepped cylinder in which the piston reciprocates. One of the elastomeric sealing elements is molded to an annular insert member that is seated in an annular recess formed in one end of the main piston body. The two-piece piston construction facilitates installation and removal of mold cavity members relative to the respective elastomeric sealing elements such that the mold cavity members can be of simplified economical construction.

Abstract: A potlike hydraulic cylinder consists of a cylinder pot (1), a piston (2), which constitutes a cover for the pot, a rubber-elastic plastic body (4), which occupies the pressure space between the cylinder pot (1) and the piston (2) and which forms a closed pocket (6) that is provided with a partition (7), which is substantially parallel to the bottom and constitutes the bottom of the pocket and is connected to at least one bottom extension (8) of the cylinder pot (1), which extension protrudes axially into the plastic body (4), and at least one pressure line (9) for a hydraulic fluid, which pressure line extends through the bottom extension (8) and the partition (7) and opens into the pocket (6). To ensure desirable operating conditions, the partition (7) is adjoined by a peripheral wall (10), which protrudes toward the piston (2).

Abstract: A compressible seal member is provided with peripherally distributed and axially spaced lubricant retaining grooves, or with radially extending lubricant channels in communication with a central lubricant reservoir. The sealing member has land portions and groove portions on the outer periphery, with the lubricant grooves or channels located along the groove portions. The seal member is installed within a pharmaceutical container with the tool having a working end received within a central aperture formed in the seal member so that the insertion forced is applied near the bottom end of the seal member to prevent compression during installation. When the pharmaceutical is expelled from the container, a plunger pushes on the accessible end of the seal member to compress the seal member axially and force the lubricant out of the grooves or channels and into contact with the inner wall surfaces of the container.

Abstract: The piston (6) guided in a cylinder (1) has at least one split so-called trapped piston ring (10) disposed in an annular groove on the piston. The circumferential face (12) of the ring remote from the inner face (11) of the cylinder bounds in the annular groove a space (23) which is acted upon by the pressure of the gas in the compression space. Starting from this circumferential face (12) the piston ring exhibits two radial boundary areas (13, 14) parallel with one another, of which the area (14) next to the compression space extends over part of the radial width of the ring. The piston ring (10) is guided by its two parallel boundary areas (13, 14) to slide against corresponding areas in the annular groove. The remaining area (16) of the piston ring next to the compression space, starting from the circumferential face (15) next the inner face (11) of the cylinder, forms a wedge face which extends at an angle of from 5.degree. to 15.degree.

Abstract: A shock-absorbing piston, a blank for the piston and a method for producing the piston include two parts being constructed radially symmetrically, but formed with outer and inner parts differing from each other. This offers great variability in the shaping of the functionally essential elements of the shock-absorbing piston.

Abstract: A hydraulic or pneumatic power unit (1) includes at least one elastomer space (4) for a compressive-force producing/transmitting elastomer (5), the space (4) being formed so as to provide the space (4) with at least one constriction point between pressurizing side and compressing side, and that the elastomer space (4) is filled with elastomer (5) by casting elastomer in situ. Elastomer space (4) is preferably in direct communication with a pressurizing space (2) for a hydraulic fluid (7), the pressurizing space (2) being connected to a pressurizing unit (20).

Abstract: A system for harnassing the combustion of a fuel and an oxidizer includes a base that has valved ports as inlets for the fuel and oxidizer and an outlet for the combustion products. The combustion occurs in a flexible container, preferably a thin walled metal bellows. The container expands in response to the combustion. This expansion is coupled to an output device to perform useful work, preferably hydraulically with a hydraulic fluid held in a rigid housing surrounding the flexible container. The housing, which can include the base, has a valved inlet and outlet for the hydraulic fluid. The system includes an arrangement to contract the container after combustion. Applications of this apparatus include modular hydraulic power generators, a marine propulsion system with water as the hydraulic fluid, an automotive-type engine with a conventional crank shaft, and a Wankel-type rotary engine.

Abstract: A drain clearing device having a transparent and hollow cylindrical body, a piston plunger assembly partially disposed in the cylindrical body, piston plunger assembly support attached to an upper end of the cylindrical body, and a drain seal attached to a lower end of the cylindrical body. The drain seal is formed from medium density, closed cell sponge rubber.

Abstract: A method of manufacturing a piston for transferring an output force to another member in response to pressurized fluid being communicated to a bore in a housing. The piston has a cylinder body made of a plurality of triaxial braided layers of carbon fibers which are placed on a mandrel with spacers located between the layers to form an annular projection of a first end and a taper of a second end. The carbon fibers are impregnated with a thermoset resin and cured to define a unitary solid structure. A cone and collar is attached to the second end to form a unitary piston. The piston is inserted in the bore and moved by the pressurized fluid to provide the output force for the other member.

Abstract: A piston stem insert to be received within a hollow receptacle that is molded at the interior of a carpule based piston, so that a piston stem may be easily attached to and detached from the piston by way of the insert. In a first embodiment of the invention, a set of flexible, anti-displacement wings extend radially from the insert to releasable and frictionally engage the inside walls of a carpule, so as to prevent an inadvertent and premature displacement of the piston through the carpule. In a second embodiment, a set of anti-rotation wings extend radially from the piston stem insert to be received within respective cavities of the receptacle that are shaped so that the wings may be rotated in a single (e.g. clockwise) direction but blocked from rotation in an opposite direction.

Abstract: A dispenser for flowable materials, such as toothpaste, includes a hollow barrel in the form of a tube open at its lower end and closed at its upper end with the flowable material being inserted in the tube. A plunger which is also in the form of a hollow tube having a closed upper end, is telescopically arranged in the barrel. A seal is effected by a hinged peripheral rim on the outer surface of the piston near its upper end. The flow of the material forces the peripheral rim to pivot into sealing contact with the inner surface of the barrel.

Abstract: A fluid actuated cylinder assembly including a piston and piston rod and having a cylinder head capable of shifting in any direction throughout 360.degree. along a plane perpendicular to the long axis of the cylinder. The piston and piston rod are rockable throughout 360.degree., the piston maintaining a fluid tight seal with the cylinder at all times. The cylinder, piston rod and shiftable head are preferably made of acetal resin or equivalent thermoplastic material. The piston comprises a sleeve made of acetal resin or equivalent thermoplastic material mounted on the piston rod and having an integral enlarged flange portion with a peripheral surface carrying a seal maintaining a sealing engagement with the cylinder. Alternatively, the piston comprises a spherical rubber member mounted on the piston rod and making the seal with the cylinder. The cylinder assembly can be pneumatically or hydraulically actuated and may be of the single-acting or double-acting type.

Abstract: A shaft or piston seal for preventing unidirection fluid flow between two concentric mating members has an annular body in the form of a ring-like member with a polygonal profile in right cross section having innermost and outermost radial portions. One of the innermost and outermost radial portions at one end of the body defines a hinge surface and the other of the innermost and outermost radial portions at a medial section of said body defines a sealing surface. The other end of said body defines a non-contact stabilizing section. The sealing surface is in the form of a sealing band which contacts one of the mating members, the hinge surface seated in the other mating member. The non-contact stabilizing member flexes and provides a counterforce for urging the sealing band against the one mating member.

Abstract: A plastic pneumatic cylinder has a cylinder housing, a piston within the housing, and a rod on which the piston is mounted. The cylinder is molded of a plastic synthetic resin and has a cylindrical bore of a predetermined diameter. The piston is molded in one piece from plastic synthetic resin, such as Delrin, in the form of a generally cylindrical body and a generally cylindrical sealing lip surronding and spaced radially from the body to seal slidably against the bore. The lip is flared out somewhat to have an edge that is of a greater diameter than the bore. The piston can be formed in single-acting or double-acting configurations. A conical return spring can be employed.

Abstract: Miniature engine operated by an expanding gaseous fluid, which comprises a cylinder (18), piston (20) and inlet valve (29), the upper part of the piston (20) cooperating with a radially expansible resilient diaphragm (28), which is secured to the piston (20) and performs momentarily a pneumatic seal-engagement function along the periphery of said cylinder (18) during the gaseous expansion phase.

Abstract: A swash plate pump includes a housing and cylinders arranged in a circular pattern around the drive shaft. Piston rods are pivotally connected at one end to the swash plate and mechanism surrounding the drive shaft and axially slidable along it controls the angle of the swash plate. The opposite end of each piston rods is fixed to a piston. In one embodiment, each piston rod is locally reduced in cross-sectional area adjacent its piston to compensate for disparity in arcuate motions of the opposite ends of the piston rod and in another embodiment, the cylinders are mounted in ball joints in the housing to compensate the disparity. One end of the housing may be formed as a manifold and double seals are provided between the compression side and the drive side of the pump.

Abstract: There is provided a height adjustable rubber pot bearing for supporting or lifting bridges. The pot bearing has an elastomer plate for transmitting and lifting or lowering loads wherein pressurized fluid is introduced between the bottom of the pot and the elastomer plate to displace the elastomer plate. A narrow slot is provided extending around the plate a small distance from and parallel with the inner side of the pot. The slot opens downwardly and has a depth of three-fourths of the plate thickness. A circular cylindrical insert is provided in the slot consisting of two parallel strips joined at their top edge with a space between them, the bottom edges of the strips being angled at right angles to form edge strips extending parallel with the bottom in opposing directions.

Abstract: A dynamic seal for effecting the sealing of a piston which is axially movable in a cylinder bore comprising a primary sealing element formed of a non-elastomeric sealing material having a hub portion secured to the piston element and an outwardly flaring skirt portion sealingly engagable with the cylinder bore. A secondary sealing element formed of a resilient metal has its central body portions secured to the piston element and defines a frustro-conical lip portion snugly engaging the exterior of the skirt portion of the primary seal element. Fluid pressure applied to the primary seal element causes it to expand the secondary seal element into a metal-to-metal sealing engagement with the bore of the cylinder.

Abstract: A slide type vacuum pump has a cylinder bore with a cylindrical piston reciprocatingly slidably fitted therein and defining a vacuum pumping chamber. A seal element is housed in an annular groove around the piston defined by a radially extending annular surface and an axially extending cylindrical surface. The seal element includes an inwardly radially extending annular portion axially abutted against the annular groove defining surface and an axially extending cylindrical portion slidingly sealing against the cylinder bore. A first spring member has an inwardly radially extending annular portion axially abuttingly holding the annular seal element portion against the annular groove defining surface, and several axially extending resilient finger portions each angled outwards somewhat and springingly pressing the cylindrical seal element portion radially outwards against the cylinder bore to effect sealing therebetween.

Abstract: A height adjustable pot bearing is provided having a pot, a steel cover plate and an elastic plate of substantially incompressible elastomeric material disposed in and completely filling the pressure chamber defined between the cover plate and the pot. A circumferential slot is provided in the base of the elastic plate radially inwardly from the outer wall of the plate so that a circumferential lip is formed. The pressurized fluid supplied to the pressure chamber of the pot bearing presses against the base of the elastic plate to lift the elastic plate and the cover plate and forces the circumferential lip radially outwardly against the wall of the pot to seal thereagainst.

Abstract: A piston seal device for a reciprocating compressor, having a piston slidably mounted in a cylinder bore and having a circumferential groove, and a resilient piston ring fitted in the circumferential groove of the piston and sealingly engageable with the cylinder bore. The circumferential groove includes a centrally recessed bottom wall for causing the piston ring to be resiliently and arcuately deformed to have a pair of opposite outer corner edges sealingly engageable with the cylinder bore. The piston sealing device thus provides a great sealing force both at the discharge stage and the intake stage, thereby improving the efficiency and lubrication of the compressor.

Abstract: A work cylinder having a piston of single-body construction and a cushioning arrangement integrally formed on the piston includes a cylinder housing having a chamber formed therein divided into first and second work chambers by the piston. First and second piston extensions extend into first and second graduated chamber portions formed at opposite ends of the cylinder housing. A sealing material, bonded to the exterior surface of the piston, exhibits a dual cup-shaped piston seal around the center portion and annular cushion seals on the piston extensions. The cushion seals are at an angle such that, when in contact with a first chamber reduction, a seal results. Additionally, in the opposite direction, the cushion seals act as a check valve whereby fluid pressure introduced to a second chamber reduction depresses the cushion seals and flows into the selected work chamber.