Abstract: A disc brake having a pair of pistons composed of a Devitroceramics having a heat conductivity of about 1.times.10.sup.-3 cal/cm.sec..degree.C. to about 4.times.10.sup.-2 cal/cm.sec..degree.C., a bend strength of about 5 kg/mm.sup.2 to about 55 kg/mm.sup.2, a Vickers' hardness of about 400, and a density of smaller than about 4.0 g/cm.sup.3. A method of manufacturing the disc brake comprises incorporating into the disc brake a pair of pistons which are prepared by mixing the component materials of the Devitroceramics, melting them to a homogeneous molten state, molding the molten materials into a piston-shaped article, annealing the article for crystallization and heating the article.

Abstract: A piston for a metering device with a glass cylinder which comprises a cylindrical core of glass, ceramic or metal and a casing of poly(tetrafluoroethylene) reinforced with 10 to 60 weight percent glass fibers.

Abstract: Each of the pistons has a metallic, ceramic or high glass nylon plastic core insert with glass-filled nylon plastic molded around it to form the finished piston. The finished piston is ready to use as it comes from the mold. The core insert is designed to maintain a substantially uniform plastic wall thickness and provide support lands behind the high pressure lands of the piston. The core insert also incorporates undercuts or grooves to prevent the core from being pushed out of the piston assembly. The grooves also allow the plastic to bond to the core. The core insert transmits the direct axial force of the push rod, and the plastic outer case supports the seals.

Abstract: Plastic wear strips are provided on a power steering piston or cylinder to improve the efficiency of translation movement of the piston in the cylinder during operation. The plastic surface of the strip, which is preferably on the piston, minimizes wear by providing a differential molecular structure at the interface between the cylinder wall and the surface of the piston since the cylinder wall is machined metal. The strips are positioned adjacent the ends of the rack where wear, caused by the load from the pressurized hydraulic fluid on the opposite side of the piston adjacent the inlet slot, is potentially the greatest. Plastic filling is provided in preferred arcuate grooves around the piston to form the wear strips. A single strip, or alternatively a group of independent strips, can be used and both serve to interrupt the surface of the piston so that molecular interaction of the two surfaces, or "slip-stick" effect, is effectively prevented. The wear strips extend through a 60.degree.

Abstract: A spherical piston for high-pressure applications. By shifting the o-ring oove to the pressure side of the major diameter of a spherical piston such that one edge of the groove is the major diameter, a very close fitting spherical piston that will not have metal to metal interference is created. Contrary to traditional spherical pistons, the spherical diameter of the present invention is less than the diameter of a cylinder wall. Elimination of metal to metal interference between the piston and the cylinder wall permits the piston to be made of harder metal than the cylinder wall without concern for damage if the piston cants on its axis within the cylinder.

Abstract: A piston for use with a rotary piston rod or so-called rotary piston can be constructed so as to utilize a solid sleeve-like piston body of a material selected from the group consisting of structural carbon and graphite. This piston body is utilized around an elongated, tubular center member which has openings extending to the interior of the piston body for the purpose of conveying hydraulic fluid so as to lubricate the piston body to facilitate relative rotation of the piston body relative to the sleeve. Appropriate grooves holding elastomeric fluorocarbon sealing rings are located in the piston body and holding structures are provided for holding the piston on the sleeve. The piston is particularly adapted for use in machines for use for cleaning tubes and pipes.

Abstract: A piston for use in pneumatic cylinders includes a tubular support with flange-like parts, a reinforcement ring received in the support and having a groove on its outside circumference, a guide ring rigidly mounted in the groove, and angular packing washers pre-vulcanized onto the reinforcement rings on both sides of the guide ring.

Abstract: A fluid pressure actuated piston that consists of two parts, a metallic portion and a nonmetallic portion, is disposed in a conventional, metallic, cylindrical housing. The non-metallic portion is slidably engaged with the metallic housing. The metallic portion has a clearance to prevent contact with the metallic housing and is connected to the non-metallic portion in such a manner as to provide a recess for a conventional O-ring seal. The recess has metallic O-ring sealing surfaces on both the piston and the housing without any metallic contact to the housing.

Abstract: A plastic disc brake piston is disclosed with a novel fluted inner core design, giving a piston with superior structural strength, crack resistance, and improved heat dissipation when used in disc brake assemblies.

Abstract: An improved fluid cylinder including a housing defining a cylinder bore and having aligned piston rod openings at opposite ends thereof, which openings are nominally coaxial with the bore. A piston rod is within the bore and extends through both of the openings and a piston is located within the bore and includes a central opening receiving the rod and having a shape complementary to that of the rod while being slightly larger than the rod so that the piston may move radially on the rod. Securing elements are provided for fixing the axial position of the piston on the rod and include an annular shoulder abutted by the piston. A seal is interposed between the piston and the shoulder to preclude leakage of the working fluid therebetween. The relative radial movement of the piston on the rod compensates for lack of precise concentricity of the bore with respect to the rod receiving openings.

Abstract: A piston for a hydrostatic machine comprises a cam follower ball in a seating in a piston body. An aperture through the piston body provides access for working fluid to reach the seating to give lubrication and hydrostatic support. A low friction insert of synthetic plastics material in the seating provides a bearing surface for the ball. The insert is retained in the piston body by a lip which prevents or inhibits extrusion of the plastics material under working load pressure.

Abstract: The cylinder and piston of an injection pump which are severely corroded by molten aluminum or the like are made of a composite sintered body containing two or more of the compounds selected from the group consisting of boron carbide, titanium diboride, zirconium diboride and boron nitride, and having excellent corrosion resistant, wear resistant and heat shock properties and high mechanical strength. One or more of the compounds selected from the group consisting of borides of tantalum, molybdenum and tungsten; carbides of silicon, zirconium, tantalum, vanadium,chromium, tungsten and molybdenum; nitrides of titanium, aluminum, silicon and zirconium; and oxides of aluminum and beryllium may be incorporated.

Abstract: A piston, such as that used in an axial and/or radial piston hydraulic translating unit, comprising a hollow-skirt portion having inner surfaces defining a substantially conical cavity filled with a core of lightweight material, the material being retained in place by snap rings resiliently mounted into annular grooves formed on the inner surfaces of the skirt portion, which mechanically interlock the core material with the piston.

Abstract: A reciprocating piston assembly for a compressor is disclosed in that a piston with at least one groove formed in its outer surface is slidably mounted in a cylinder bore and at least one piston ring made of polymers of fluorine-containing olefin monomers, the outer diameter of said piston ring being smaller than the diameter of said cylinder bore prior to operation of the compressor but said piston ring being in contact with the inner wall defining said cylinder bore during operation of the compressor.

Abstract: A differential piston is reciprocable in a cylinder and subdivides the latter into a first and a second chamber. The piston has a piston rod which extends through the second chamber outside the cylinder and is adapted to open and close the mold of a molding machine. An admitting conduit admits pressure fluid into the first chamber, and a connecting conduit connects the two chambers and has a valve interposed in it so that the two chambers communicate with one another only while the first chamber is pressurized, not while the second chamber is pressurized in the absence of pressure in the first chamber. A sealing arrangement between the piston and an inner circumferential surface of the cylinder is effective for preventing the flow of pressure fluid from the second to the first chamber when the latter is at a lower pressure than the former.

Abstract: A piston and slipper arrangement for a hydraulic pump or motor includes a tortuous fluid flow passage through the piston to a fluid pressure recess in the thrust face of the slipper at the opposite end of the piston. The fluid passage is formed by a plurality of spaced, cylindrical pockets interconnected by restricted flow channels which tangentially join the pockets.

Abstract: The invention provides a hollow core filled piston including core retaining means for mechanically interlocking and retaining a core of filler material within the piston against angular and axial displacement. The piston includes a hollow skirt portion defining a stepped-bore cavity, and retaining means for retaining a core of filler material within the cavity comprising a plurality of annular projections formed from the shoulder between the stepped bores. The invention further provides a tool for cutting and displacing segments of the shoulder to form the annular projections.

Abstract: A piston for a compressor having at both ends a step-down portion which defines an annular cavity when the piston is mounted in the cylinder, the said cavity being very thin while its length is dependent on the weight and the length of the piston. A rider ring is located at the center of the piston and piston rings are inserted between the rider ring and the step-down portion.

Abstract: A piston assembly adapted for use in nonlubricated high pressure compressors, comprising a piston having a plurality of peripheral grooves therein with a ring assembly in each groove constituted of one seal ring and one guide ring in a common groove. The guide ring is behind the seal ring in a direction away from the compression end and has a surface remote from the compression end which is at least partially conical in shape and abuts against a corresponding conical shaped surface of the associated groove. The seal ring and guide ring abut along planar surfaces, the guide ring being made from non-metallic material such as a carbon-graphite material providing higher resistance to shape deformation then the material of the seal ring which can be polytetrafluoroethylene. The guide ring thus prevents plastic deformation of the seal ring particularly at very high pressures of compressed gas.

Abstract: A die casting machine has a piston rod connected to its main ram for positioning the ram as the piston rod extends and retracts from a cylinder. A control system is provided which directly senses the position, velocity and acceleration of the piston rod. A smooth continguous outer surface is formed on the piston rod. Magnetic and non-magnetic materials spaced alternately axially along the rod provide a series of magnetic discontinuity fields along the piston rod. Transducers are provided to sense the magnetic discontinuities as the piston rod moves to provide signals indicative of the position, velocity and acceleration of the piston rod. An electrohydraulic servo valve is electrically connected to the transducers and to a control console for moving the piston rod and for recording its position, velocity, and acceleration.