Abstract: A piston includes: a piston head; and a piston skirt connected to the piston head, wherein the piston skirt includes wall portions protruding outward from a surface of the piston skirt, the wall portions adjacent to each other in a circumferential direction of the piston skirt are inclined in directions opposite to each other with respect to a direction of movement of the piston in a bore for the piston, and define a tapered portion, and the tapered portions are spaced away from each other in the circumferential direction of the piston skirt.

Abstract: A handheld tool with a pneumatically operated linear oscillating drive is provided. The handheld tool has a motor housing and a piston movable in the motor housing, which separates the two working chambers of the motor housing from one another. A piston crown faces toward one chamber of the two working chambers, with a compressed air supply line toward the motor housing and a slide valve, which controls an alternating supply of compressed air to one and the other of the two working chambers, and with an exhaust air opening in the motor housing. The handheld power tool is distinguished in that the piston additionally has a piston skirt facing toward the other chamber of the two working chambers.

Abstract: The invention relates to a supply device for the supply of pressure fluid into at least one vehicle brake or into a pressure fluid accumulator, wherein a piston is movably arranged in an accommodating member, a carrier bears a non-return valve arranged coaxially to the piston for the purpose of ventilating a working chamber into which the piston plunges , and wherein a resetting spring is arranged between the carrier and the piston. It is the essence of the invention that a multi-piece cage allows inserting the resetting Spring into the cage parts, the cage parts comprise fastening means that lock the cage due to relative displacement of the cage parts, and the resetting spring is caged and simultaneously elastically preloaded under the relative displacement of the cage parts.

Abstract: The present invention relates to a piston (10, 110) for a combustion engine having a basic element (11, 111) and a ring carrier element (12, 112) held on the basic element (11, 111) with a top land (25, 125) all around its circumference and ring belt (26, 126) all around its circumference. It is provided in accordance with the invention that the ring carrier element (12, 112) grips around the basic element (11, 111) at least partially and is held on the basic element (11, 111) by means of a press fit.

Abstract: A piston assembly for a double-acting engine such as a double-acting Stirling engine. A pair of sealing rings located on opposite sides of a sealing washer are positioned between a base section and a dome section of a piston head. These sealing rings are alternatively urged into sealing engagement with the cylinder bore as the piston reciprocates. A single sealing ring design is also disclosed in which the sealing ring is urged into constant sealing engagement by positive pressure accumulated with an interior cavity in the piston head.

Abstract: In order to reduce the weight and manufacturing cost of a piston for a hydraulic actuating cylinder, the piston, the piston rod and the external reinforcement cap are combined to form a unitary integral part. The unitary part is advantageously a single extrusion product. The piston is shaped so as to be able both to slide along the length of the inner cylinder wall, and to tilt upon deflection or lateral displacement of the piston rod in the bore of the cylinder, while still maintaining its hydraulic seal.

Abstract: A cryogenic refrigerator includes a displacer and a cylinder therein for generating a very low temperature. And, a sealing ring is provided in an inserted condition within a ring shaped groove which is formed at an outer peripheral portion of the displacer, the sealing ring having resilience for extending itself outward so that a sealing member on an outer diameter thereof is enlarged and that an outer portion of the sealing ring is slidably contacted to an inner face of the cylinder, and the sealing ring being made of non-magnetic alloy, thereby a magnetic noise and disturbance of an outer magnetic field due to the cryogenic refrigerator are greatly decreased.

Abstract: Telescoping vibration damper consisting of a work cylinder, a piston which is guided on a piston rod and divides the work cylinder into two work chambers, and passages in the piston which empty on at least one end into a ring-shaped chamber, the encircling control edges of which are covered by valve plates, whereby there is at least one additional valve plate located at some axial distance from the first valve plate, which together with a support element forms an additional ring-shaped chamber, whereby the first and additional ring-shaped chambers are connected to one another by means of a flow connection.

Abstract: A fluid storage tank utilizing an isolation seal in which a leak proof isolation seal covers the entire head of the piston of the storage tank requiring only a single fluid tight seam to seal off the fluid storage chamber from the remainder of the storage tank. The isolation seal has a circumferential notch located proximate to its outer periphery which permits the isolation seal to rupture along a predetermined path. Elastomeric annular seals on the piston provide a dynamic seal to prevent the fluid from leaking while the piston is moving to eject the stored fluid. The isolation seal is welded or otherwise fastened to the interior surface of the tank at a location behind the elastomeric seals so that the latter need not pass over the weld during movement of the piston. The interior of the tank has a first or larger diameter section, a second or smaller diameter section, and a tapered transition section which is disposed therebetween just past the rupture zone of the isolation seal.

Abstract: A banded cylindrical piston for use in fluid cylinders is produced by hot-forming a relatively thin, flat washer made of polytetrafluoroethylene (PTFE) onto a grooved piston. A hot-forming sizing tube has a beveled entrance end on which the washer is initially preheated, a first section of a greater diameter than the end diameter of a finished unit for preliminarily elongating the preheated washer as it assumes sleeve shape and a final hot-forming second section in which the PTFE material is forced to flow under pressure into the piston grooves. The cross-sectional configuration of the groove or grooves is such as to enhance flowability of the material during hot-forming toward and into contact with a side of the groove nearest the head end of the piston to improve the mechanical gripping effect of band to piston. The side of the groove nearest the head end of the piston is preferably at an acute angle relative to an adjacent land on the periphery of the piston.

Abstract: A piston for use in a hydraulic cylinder which is subject to sudden and extremely high shock load pressures and high temperature operating conditions is provided with a plurality of interlocking axially-spaced circumferential grooves. A relatively thin, flat washer of heat-formable fluoropolymer is snapped over a retaining ring integral with the piston and the piston is then moved axially through a heated hot-forming cylinder, causing the washer to conform to the cylindrical shape of the piston. At least one circumferential groove has a side wall which is undercut relative to its cylindrical surface to provide a locking angle. Preheating the washer prior to hot-forming the band and forming a sloping ramp in opposition to the undercut side wall result in improved flow of the fluoropolymer toward the undercut side wall. An additional advantage of the preheating is the formation of an improved band skirt with an improved, sharply-defined sealing edge.

Abstract: A fluid storage tank utilizing a shear seal in which a leak proof static shear seal covers the entire head of the piston of the storage tank requiring only a single fluid tight seam to seal off the fluid storage chamber from the remainder of the storage tank. The shear seal has a circumferential notch located proximate to its outer periphery which permits the shear seal to rupture along a predetermined path. Elastomeric annular seals on the piston provide a dynamic seal to prevent the fluid from leaking while the piston is moving to eject the stored fluid. The head of the piston flattens any protruding portions of the ruptured shear seal against the walls of the storage tank.

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 piston for use in a hydraulic cylinder which is subject to sudden and extremely high shock load pressures and high temperature operating conditions is provided with a plurality of interlocking axially-spaced circumferential grooves. A band of a heat-formable fluoropolymer is snapped over a retaining ring integral with the piston and the piston is then moved axially through a heated hot-forming cylinder, causing the washer to conform to the cylindrical shape of the piston. At least one circumferential has a side wall which is undercut relative to its cylindrical surface to provide a locking angle. A method of washer preheating prior to hot-forming the band results in better flow of the fluoropolymer toward the undercut side wall. The method of preheating also produces a band skirt with a relatively sharply-defined sealing edge.

Abstract: A piston installed into a cylinder of an engine includes annular projections formed in axially spaced relation on a top land facing a cylinder inner wall and having a saw-toothed cross-section in which the external diameter of the projections are such that, when cold, that adjacent the lower end of the top land is greater than that adjacent the upper end thereof. Thereby the effective clearance between the top land face and the cylinder inner wall is reduced. This causes a reduction in the hydrocarbon content of the incompletely consumed combustion gas, and prevents the temperature from rising in the top ring groove and thus prevents the wearing of the groove.

Abstract: A peripheral sliding seal for sealing the liquid propellant in a cylindrical tank 10 containing a piston 14 for positive expulsion of the liquid propellant. The seal comprises a peripheral inward flange member 16 around the piston periphery adjacent the inner wall of the tank, an annular pressure ring 18 bonded to the flange member 16 and forming several recesses therewith, one recess containing a compliant sealing ring 20 and the other containing a shear seal 32 bonded both to the flange member 16 and to the entrance head 12 of the tank. The bonds prevent internal and external leakage of the liquid fuel during storage. Pressurization of the piston 14 permits the piston 14 to move and breaks the shear seal 32. The compliant-ring seal slides with the piston 14, the compliant ring 20 being pressed against the inner wall of the tank by resilient fingers 34 of the pressure ring 18 to form a sliding seal.

Abstract: It is a question of a piston and cylinder unit comprising a cylinder barrel defining a piston space, a piston able to run axially in said barrel with a support action due to a peripheral bearing surface of the barrel. The piston includes at least one annular running belt which is coaxially arranged thereon along part of the length of the piston. The belt has a surface facing radially outwards which makes contact with the inner bearing surface of the barrel with sliding fit to support the piston, while an inwardly directed surface of the belt bears on an outer peripheral surface of the piston, which is spaced from the bearing surface of the barrel. The belt further has an inwardly directed retainer spur fitting into a groove-like peripheral recess in the piston. The belt is made of a material with resiliently elastic properties and is interrupted at one position on its periphery so that in the fitted condition of the belt there is a closed interruption able to be opened out for fitting purposes.

Abstract: An oil control ring for a piston in an i.c. engine comprising an expander ring and two lamellar rails which scrape the oil from the cylinder wall. The expander ring has two series of lugs arranged alternately on each side, which support the rails and two series of dimples arranged alternately on each side which space the rails from the expander ring. The expander ring has notches in its outer and inner circumference and is bent into a circular form. Its free ends form a butt joint.