Abstract: A piston assembly is provided for a human-powered vehicle. The piston assembly includes a main body, a primary seal and a secondary seal. The main body is configured to be movable from a rest position to an actuated position along an actuation direction in a cylinder bore. The primary seal includes a primary seal body arranged on the main body, the primary seal body being made of the first seal material. The secondary seal includes a secondary seal body arranged on the main body at upstream of the primary seal with respect to the actuation direction. The secondary seal body is made of a second seal material that is more elastic than the first seal material.

Abstract: A rotatable plasma torch is provided which can easily rotate when used in robotic or automatic cutting system while minimizing damage to internal connections of the torch. The torch is provided with a sleeve structure on the torch handle where there is no structure or component positioned between the sleeve and the exterior of the torch handle.

Abstract: A sealing apparatus for a square piston used for compressing and feeding a fluid is applied to equipment used for compressing or feeding the fluid on the basis of a new concept, and maintains a perfectly sealed state to thus guarantee stable operation of the equipment. The sealing apparatus includes a first sealing member having upper, lower, left-hand and right-hand sides and a first square hole in contact with the square piston, a second sealing member having upper, lower, left-hand and right-hand sides and a second square hole in contact with the square piston, first and second elastic means disposed on the upper and right-hand sides of the first sealing member and installed in a cylinder housing, and third and fourth elastic means disposed on the lower and left-hand sides of the second sealing member and installed in the cylinder housing.

Abstract: A fluid cylinder for high temperature applications is disclosed. The fluid cylinder includes an extensible member that moves between a retracted position and an extended position by forcing a fluid, such as a pneumatic fluid or a hydraulic fluid, into the cylinder. In order to seal the extensible member against an internal surface of the cylindrical housing, the extensible member includes a sealing member defining a plurality of grooves. A corresponding plurality of metallic sealing rings are placed in each of the grooves. The sealing rings include a gap that allow for thermal expansion. The sealing rings are positioned in the grooves so that the gaps on the rings are in a staggered arrangement in the axial direction. Further, a metal alloy coating may be applied to at least certain parts of the fluid cylinder. Through the above configuration, the fluid cylinder can be made without any polymeric sealing rings, composite bearings, or lubricants that may degrade during high temperature applications.

Abstract: The compressor contains at least one piston (5) guided in a dry-running manner which, together with a cylinder insert (33), bounds a ring gap which is open over the common longitudinal section in each case and permits a leakage flow of the compressed medium. The piston (5) is coupled via a piston rod (42) to a support part (38) which is displaceably guided in the direction of its longitudinal axis (6) and is connected to a drive device. The piston rod (42) cooperates with the piston (5) and the support part (38) via support surfaces (43) which are convex at the end faces and permit relative movements of the support part (38) with respect to the piston (5) which extend transversely to the longitudinal axis (6). Accordingly, a parallel guidance of the piston (5) in the cylinder insert (33) is achieved which is not influenced by oscillations of the driving parts.

Abstract: An improved cylindrical working member and associated system comprising a simple cylindrical sleeve having an outer surface with two spaced grooves surrounding a cylindrical land. At the other end, a single groove is formed. A "SANDWICH" consisting of a simple O-ring, a single back-up ring, a low snap ring is installed in each groove. An additional low friction snap ring forms a limit stop front cap. A plurality of the cylindrical sleeves can be employed to form a telescoping cylinder system. An additional embodiment using a guide member consisting of a plurality of square tubes of sequentially increasing cross-section formed into a non-rotating telescoping guide member to attach one end to the telescoping system, and other end to a plug of the hollow central rod. A simple system is used for extending and retracting the telescoping cylinder.

Abstract: A piston and ring assembly operative within a cylindrical bore wall to retain pressurized fluid to one side of the assembly, the piston having a crown and an annular side wall for movement along the bore wall.

Abstract: A fluid-pressure-operable actuator system, for operating an aerodynamic control surface, including an actuator comprising a casing, piston and output member. Annular sealing means carried by the piston sealingly engages with the casing while annular sealing means disposed in an aperture through which the output member extends sealingly engages that member. Bearing means circumferentially flank the sealing means of the piston and/or the aperture and include parts of readily- and locally-deformable material, respectively in relatively-slidable load-bearing engagement with the casing and/or the output member. In the event that damage is sustained by the surface of the actuator engaged by the sealing means the bearing means is sufficiently deformed as to permit relative movement of the casing and output member to continue under the power of at least one other actuator associated with said control surface.

Abstract: In a pump having a cylinder liner, there is a piston therein, a seal around the piston and rear wearband around the piston body to align the piston within the liner. An elastomeric seal ring is in sealing and sliding contact with the liner. A gap filler, with minimal axial creep and controlled radial creep, abuts the rear surface of the seal and maintains continuous contact with the liner thereby continuously closing the extrusion gap between the gap filler and the liner as the liner wears. The wearband has a plurality of angled grooves longitudinally traversing it. Abrasive particles are directed within and through the grooves in the wearband while a source of liquid is communicated into the piston body, through water channels in the gap filler and through the flowpaths in the wearband to create a vortex action which washes the liner wall. The wearband insures no metal to metal contact between the piston and liner and provides a constant piston gap between the metal piston and liner.

Abstract: A packer nose assembly for pumping downhole equipment of the free type into and out of boreholes. The assembly includes a mandrel having a lower end portion attachable to the downhole equipment and an upper end portion terminating in the form of a fishing neck. One or more packers are slidably received in a telescoping manner upon the mandrel and anchored into position by spaced sleeves which are likewise slidably received upon the mandrel. The packer is cylindrical in form and includes a plurality of spaced fins formed about the exterior thereof with each fin being circumferentially disposed about and radiating from the body portion. The fins taper in thickness in an outward direction from the body 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.