Abstract: Piston compressor for compressing gas, comprising a frame with at least one cylinder which has an essentially horizontal axis, a piston which is reciprocable in the cylinder, a piston rod which at one end thereof is fixed to the piston, while the other end thereof is coupled to a crosshead which is guided in the frame and is reciprocable by a drive mechanism, and bearing means which support the piston/piston rod unit, formed by the piston and the piston rod connected thereto, relative to the frame.

Abstract: A reciprocating engine (10) comprises separate cylinders (12 and 15) for air compression and expansion with heating of the compressed air taking place in a heat exchanger (17) or combustor (64) located between the cylinders (12 and 15). The flow of gas into the expander cylinder (15) is controlled by an admission valve (37). The stem (41) of the admission valve (37) extends transversely across the expander cylinder (15) and is cooled by the flow of exhaust gases out of the expander cylinder (15).

Abstract: A bearing assembly for a piston rod of a linearly reciprocating piston type engine having a cylinder (11), a piston (12) movable axially in cylinder (11), at least one piston rod (13) secured to and projecting axially from one side of the piston to be received in a respective bearing assembly (17) mounted in a cover assembly at one end of the cylinder and which guides the movement of the piston/piston rod assembly, said bearing assembly comprising: an inner annular array of balls (18) which roll on the cylindrical outer surface of the piston rod (13) during its reciprocation, and housed in an annular space defined between the cylindrical outer surface of rod (13) and a sleeve (19); bearings (20) which rotatably mount sleeve (19); and means for rotating the sleeve (19) about the axis of the piston rod (13) so as to apply continuous rotation to the balls during each cycle of reciprocation of the piston rod and thereby enable a hydrodynamic lubrication of the bearing assembly.

Abstract: A positioning device having a high rigidity and smooth positioning characteristics. The positioning device holds a piston formed integrally with a table within a cylinder and has pressure-adjusting elements in two pressurizing chambers in the cylinder partitioned with the piston. A gas is ejected into a clearance between the piston and the cylinder to hydrostatically support the piston. The emitted gas is introduced into the two pressurizing chambers to drive the piston and the table by the pressure difference between the pressurizing chambers. The pressure-adjusting elements include nozzles for emitting the gas in the pressurizing chambers and pressure-adjusting bodies for changing the opening degree of the ejecting port of the nozzles.

Abstract: A pair of opposed pistons (17) are interconnected by a connecting link assembly (19) defining opposed parallel guide surfaces (24), transverse to the axes of the pistons. A drive block (28) is rotatably mounted on a crankpin (16) of a crankshaft by a bearing shell (71a, 71b) and has parallel bearing plates (31) slidably engaged with the guide surfaces (24). Lubricating oil is supplied to ports (59) in the bearing plates, just before each plate is substantially loaded, from leading and trailing drillings (56L and 56T) in the crankpin (16), ports (76, 77) in the bearing shell and passages (73, 74, 75) in the drive block.

Abstract: A roller-contact bearing device with a reduced clearance for a power-assisted steering system having a first roller-contact bearing for absorbing axial forces exerted on a steering shaft and a second roller-contact bearing for transmitting the axial forces to a casing. The second roller-contact bearing is urged toward shaft by an spring disc to oppose the axial forces being applied to the shaft.

Abstract: A driving mechanism usable in an electron beam exposure apparatus, X-ray exposure apparatus, ion beam exposure apparatus, evaporation apparatus, chemical vapor deposition apparatus or otherwise, for rectilinearly moving a wafer carrying stage in a vacuum chamber is disclosed. The mechanism includes a guide shaft, a partition flange fixed to the guide shaft, a pair of bearing assemblies slidably mounted to the guide shaft and disposed on the opposite sides of the flange, a coupling barrel for coupling the paired bearing assemblies and covering the guide shaft portion between the bearing assemblies, and a fluid supplying system for supplying fluids to the opposite sides of the partition flange. With this structure, the stage can be moved rectilinearly by controlling the fluid pressures on the opposite sides of the flange, while retaining high vacuum in the vacuum chamber.

Abstract: A piston engine comprising a piston movable in a recriprocating manner in a cylinder, while during operation a wedge-shaped gap is present between piston and cylinder. The piston divides the cylinder into a first chamber and a second chamber, which communicate with each other through the gap. A stable central position of the piston is obtained by means of the wedge-shaped gap, which mainly determines a pressure difference between the first chamber and the second chamber. A particular application of the piston engine is a cryo-cooler, by means of which, for example, processors of computers are cooled.

Abstract: The space within the interior cavity (7) of the piston (1) limited by the partially spherical head (5) of the connecting rod (6) is filled with a viscous, pasty or plastically ductile fluid (13), practically incompressible at the operating temperatures and pressures of the piston (1), the diameter (D) of the cylindrical support (8) which limits laterally the cavity (7) being very slightly greater than the diameter (d) of the partially spherical head (5) of the connecting rod (6) so that the clearance during operation between said support (8) and said head (5) is sufficiently minor to prevent any leakage of said fluid (13) from said space at the operating temperatures and pressures of the piston.

Abstract: A piston for a gas-operated linear actuator wherein a double-acting piston moves axially within a cylinder in response to gas pressure applied intermittently to chambers on either side of the piston. The piston has reservoirs in the form of holes in each of its faces and a pair of spaced-apart circumferential grooves, one communicating with the holes in one piston face and the other with the holes in the other piston face, the two sets of grooves and holes being kept out of communcation with one another. Gas under pressure introduced into one chamber forces the piston to move toward the opposite chamber, and a portion of the gas passes into the holes and out through the adjacent groove, providing a stream of gas between piston and cylinder walls, producing a gas-bearing effect.

Abstract: A free-piston Stirling machine has a piston which can reciprocate and also rotate within a cylinder and which is supported and centered in the cylinder by a grooved dynamic bearing, the piston having two end faces which are acted upon during operation by different fluid pressures. The piston includes at least one sealing part having a circular-cylindrical smooth sealing surfaces and at least one bearing part which is provided in its peripheral surface with a groove pattern. The length of the sealing surface and the size of the gap between the sealing surface and the cylinder wall are selected such that the pressure difference across the bearing surface is reduced so that the piston remains free of radial dynamic instability during operation.

Abstract: Apparatus for sealing the gap between a piston and engine cyinder wall of either a reciprocating engine or a reciprocating compressor. The apparatus includes a plurality of functionally-identical, gas-bearing-supported seal blocks that locate in a slot running circumferentially around the engine piston. Gases fed from the engine chamber to the gas bearing carrying the load on the seal block in the direction of piston travel. The seal block includes a gas accumulator cavity for gas storage. An orifice feeds gas from the gas accumulator cavity to the gas bearing interfacing between the seal block and the engine cylinder wall. The apparatus also includes a reaction piston having gas communicated thereto from the engine chamber.

Abstract: A gas bearing system for a piston 24 of a linear compressor 20 in which gas from the piston head space 26 is injected into a high pressure reservoir 106 within the piston when the working fluid in the piston head space is at high pressure. In one embodiment, gas from a low pressure reservoir 104 is exhausted into it when the piston working space fluid is at low pressure. Gas flow is directed between high pressure and areas of low pressure during operation of the piston. This gas flow is directed between the piston and its surrounding sleeve 30 in a manner which holds the piston 24 in suspension away from the sleeve 30 to thereby reduce the friction and wear experienced by the piston and sleeve.

Abstract: An accommodating linkage device which operates in three modes to provide, upon command, either: (1) a standard, resetable, rigid linkage between two objects; (2) a flexible linkage which responds to relative motion (forces) between two objects; (3) or an arbitrary, rigid linkage between two objects. The device includes two ball joints which connect to the two objects, a pair of locking pistons, and a pair of alignment pistons. Operation of the device is in response to either control signals or to forces generated by the relative motion of the two objects, depending upon operating mode.

Abstract: A gas bearing system for a piston 24 of a linear compressor 20 in which gas from the piston head space 26 is injected into a high pressure reservoir 106 within the piston when the working fluid in the piston head space is at high pressure. In one embodiment, gas from a low pressure reservoir 104 is exhausted into it when the piston working space fluid is at low pressure. Gas flow is directed between high pressure and areas of low pressure during operation of the piston. This gas flow is directed between the piston and its surrounding sleeve 30 in a manner which holds the piston 24 in suspension away from the sleeve 30 to thereby reduce the friction and wear experienced by the piston and sleeve.

Abstract: A glide shoe of a hydraulic piston machine has a glide face which is in gliding contact with a gliding surface of a piston-reciprocating element. The glide shoe has a bore which communicates with an interior of a housing of the machine and extends toward the glide face so that a working medium which flows through the bore causes build-up of a hydrostatic pressure between the bore and the glide surface of the piston-reciprocating element. The glide face is continuous and is interrupted only by recess means which occupies not more than a relatively small portion of the glide face so that a relatively high hydrodynamic pressure can build up between the remainder portion of the glide face and the glide surface of the piston-reciprocating element during working movement of the glide shoe relative to the piston-reciprocating element.

Abstract: An integral power steering gear assembly includes a piston and cylinder combination having greater output efficiency through improved fluid balancing and cushioning of the piston at its ends. The improved cushioning utilizes oil capillary slots in lieu of previously proposed epoxy resin strips. The slots may be fed with high pressure fluid filled by feed grooves along the sides of the piston adjacent the output rack. The slots are designed to have a shallow depth, preferably 0.001 inch-0.0025 inch, which is sufficient to provide for high capillary attraction of the oil molecules to the slot. The trapped oil molecules prevent slip stick action, that is molecular interaction between the piston and cylinder wall, but at the same time, the oil molecules remain trapped or isolated within the walls of the slot thereby minimizing leakage from the slot. The operating oil is delivered with higher efficiency in the power steering unit by a bifurcated oil delivery passage communicating with the inlet slot of the piston.

Abstract: A sealing device for a high pressure hydraulic piston mechanism in which the gap between the cylinder in which the piston is slideable to pressurize delivery fluid therein is sealed by sealing fluid drawn from a separate supply to that of the delivery fluid, delivery means being associated with the sealing fluid supply and being operable in response to pressurization of the delivery fluid to deliver sealing fluid to said gap at a pressure sufficient to form a seal therein, the sealing fluid of said seal being in direct contact with the pressurized delivery fluid and the piston being movable in at least one hydrostatic bearing supplied with sealing fluid in parallel to the supply thereof to said gap between the piston and the cylinder.

Abstract: An integral power steering gear with a valve in the piston is provided having a short piston and cylinder to conserve space and weight. The input shaft is mounted on a bearing carried by an inwardly projecting annular portion on the bearing cap. The projecting portion mates with a recess in the end of the piston when the piston is moved to the full extreme in that direction. The valve guide pin has been relocated at the input shaft end of the valve where maximum support of the valve is realized and improved reversibility of the valve under all conditions is gained. In the bearing cap, both a high pressure seal and a low pressure weather seal are provided. An insert ring between the two seals serves as backup to the high pressure seal. In an alternative embodiment, the insert ring may be tapered toward the inside of the gear to allow use of a thin wiper-type seal.