Abstract: New methods and devices are described that are aimed at preventing the outbreak of fire in a hydraulic rotor brake. These methods and devices can be used in the rotor brake of a helicopter and comprise a first and second seal, with a drain groove positioned in between these two seals to drain leaked fluid away from the hot parts of the brake. In the brakes described, the second seal is positioned closer to the heat sink of the brake than the first seal. The drain groove is also connected via a channel or channels to a drain outlet or outlets.

Abstract: An optical fiber connector includes an optical fiber ferrule and a single-piece housing in which the ferrule is received. The housing can be installed in an adapter to make an optical connection. A rotational locking mechanism has a rotor mounted on the housing for rotation with respect the housing about a rotational axis. The rotor can be rotated between a locked position and an unlocked position. The rotational locking mechanism is configured to inhibit the housing from being withdrawn from the adapter in the locked position of the rotor and to permit the housing to be withdrawn from the adapter in the unlocked position, and further comprising a guide pin, wherein the housing comprises an integral guide pin retainer configured to hold the guide pin in place on the housing.

Abstract: An armor system includes an appliqué comprising a high fluid retaining material (HFRM) and a plate configured to hold the appliqué against a compartment, wherein the armor system is adapted so that upon impact of a blast wave upon the plate, the HFRM is vented away from the compartment. The armor system may be adapted to a vehicle. In another embodiment, an armor system includes a plate operably connected to a plunger, one or more rods of brittle material operably contained within a tube, wherein the armor system is adapted so that upon impact of a blast shock wave upon the plate, the plate transfers the blast shock wave to the plunger and then to the contents of the tube. Optionally, the tube also contains HFRM.

Abstract: A linear actuator includes a cylinder main body. With respect to the cylinder main body, a slide table is disposed for reciprocal displacement through a guide mechanism, which is disposed on the cylinder main body. A stopper mechanism having a stopper bolt is disposed on one end of the slide table centrally in a widthwise direction perpendicular to the longitudinal direction of the slide table. In addition, when the slide table is displaced along the cylinder main body, an end of the stopper bolt comes into abutment with an end of a cover of the guide mechanism, whereupon the slide table becomes engaged therewith and movement of the slide table is stopped.

Abstract: An anodized aluminum hydraulic leveling cylinder 10 for a vehicle includes an extruded hollow body 20 having a vehicle attachment portion 24 for attaching the body to the underside of a vehicle. A piston 80 is slidably fitted into the interior of the body. The piston is formed of ductile aluminum capable of being machined to a desirable shape and dimensions. The piston is hard anodized and PTFE coated for durable and silent operation. Hydraulic oil passage means 23a, 23b is formed in the body, and a cap 50 with a pair of dual flow-through passages 53 is attached to the top end 30 of the body for permitting the flow of pressurized hydraulic oil into and out of the interior of the body to effect axial movement of the piston. Hydraulic fluid may be transferred through one or more hollow mounting bolts.

Abstract: A modular fluid end for a multiplex plunger pump, each module machined from a single-piece steel forging with a plunger bore intersected by a linear suction/discharge bore and pumped fluid is discharged straight out through a top of the module into a discharge manifold made up using 1502 frac iron components. A compression clamp applies a crush load to opposed sides of the modules to extend service life.

Abstract: Disclosed is a small rotary cylinder device wherein friction loss is reduced and energy is conserved by reducing effects of a reaction force applied from cylinders to pistons, which is incorporated in a piston composite body and which linearly reciprocates, the piston composite body being eccentrically connected to a first crank shaft rotating about a shaft. Guide bearings (1c) guide linear reciprocation of first and second piston assemblies (7, 8) attached to second tube bodies (6b), which are caused by rotating a first crank shaft (5) about a shaft (4) and rotating a piston composite body (P) about the first crank shaft (5), in the radial direction of a rolling circle of second imaginary crank shafts (14a, 14b), which has a radius 2r and which is centered at the shaft (4).

Abstract: A pump can include two pistons, each piston having one side exposed to a support pressure and another side exposed to a respective annular chamber, the chambers being pressurized greater than the support pressure. Fluid can be discharged from one annular chamber and received into the other annular chamber by displacement of the pistons. A method of testing a fluid can include pressurizing the fluid in response to increasing a support pressure exposed to one side of each of two pistons, thereby increasing pressure in chambers exposed to respective other sides of the pistons, and then displacing the pistons, thereby flowing the fluid through a test manifold assembly. A fluid test system can include a pump having a support pressure exposed to sides of two pistons, and another side of each of the pistons being exposed to a respective annular chamber. Each annular chamber can be connected to a sensor.

Abstract: A hydraulic device that includes a case, and a substantially hollow rod slidably extending from the case. The rod has a ram on a first end thereof that caps the rod to form a first hydraulic piston. The rod has a second hydraulic piston on a second end thereof, inside the case. The first and second pistons are at least partially radially coextensive, and a pressure barrier inhibits high pressure on the first piston inside the hollow rod from reaching a side of the second piston that faces the first piston.

Abstract: A compressor, as well as a lightweight and strong casting for a compressor, are disclosed. The compressor, which may be a reciprocating compressor for use in compressing high-pressure refrigerants such as CO2, includes substantially reduced wall thicknesses (t) compared to prior art castings. The side walls of the compressor can be manufactured to such reduced thicknesses (t) through the use of a bridge spanning across the crankcase. This not only allows the opposing side walls to be manufactured of a thinner material, but the bottom cover removably mounted to the crankcase can be manufactured from a thinner and lighter material as well. Through the use of such a bridge, the resulting compressor is not only able to satisfy current strength requirements, but at significant weight, size and cost savings as well.

Abstract: A bearing assembly for mounting a pair of spaced parallel actuators (3) between a wing and a control surface of an aircraft so that the actuators control deployment of said control surface from the wing in tandem is disclosed. The bearing assembly comprises a fixed member (18) for attachment to the aircraft and a movable member (8) attachable to the actuators. The fixed and movable members are coupled via a part-spherical bearing (14) and are configured such that the part-spherical bearing is located in the space between the actuators (3).

Abstract: A telescopic undercarriage for raising and lowering a frame. The undercarriage includes a base section having a pair of parallel base legs extending from a first end to a second end of the base section, the base section including a first plurality of braces extending between respective upper surfaces of the base legs and a second plurality of braces extending between respective lower surfaces of the base legs, the base legs, first plurality of braces and second plurality of braces collectively providing an elongate central base section passage. The undercarriage also includes an extendable section slidably disposed within the base section passage and having opposed legs, a drive system for extending and retracting the extendable section relative to the base section.

Abstract: A cylinder body includes a first guide surface made up from first guide grooves and a first bulging portion, wherein a slide table is displaceably supported on the first guide surface via a guide mechanism. Additionally, guide members of a guide block that constitutes the guide mechanism are inserted into and fixed within the first guide grooves. Further, the cylinder body is equipped with a second guide surface, which is formed with substantially the same shape as the first guide surface. In the event that the first guide surface is oriented upwardly and the slide table is installed thereon, the second guide surface acts as a mounting surface, whereas, in the event that the second guide surface is oriented upwardly and the slide table is installed thereon, the first guide surface acts as the mounting surface.

Abstract: A pump includes a base and a cylinder installed on the base. The base defines a pumping channel. The cylinder defines a first chamber and a second chamber with a diameter different from that of the first chamber. The first and second chambers are in communication with the pumping channel. A first check valve only allows air to travel into the pumping channel from the first chamber. A second check valve allows air to travel into the pumping channel from the second chamber. A first piston is movable in the first chamber. A second piston is movable in the second chamber. A control device prevents the venting of air from the chambers in a first mode, vents air from the second chamber without traveling through the pumping channel in a second mode, and vents air from the first chamber without traveling through the pumping channel in a third mode.

Abstract: A telescopic lifting assembly designed particularly for the hydraulic height adjustment of a medical treatment table includes two antiparallel juxtaposed linear drives (2, 3) connected functionally one behind the other in the direction of actuation (1) whereby the inner components (6) are connected to a coupling piece (7) which is provided with guide surfaces (14) cooperating with the outer components (5) in the direction of actuation (1). A secure and stable guiding mechanism is made possible thereby along the entire lifting range.

Abstract: An aircraft brake piston housing (10) has a composite body (14) including a plurality of fibers embedded in a matrix, the body (14) including a central bore (18) and a plurality of circumferentially disposed openings (23) surrounding the bore (18), at least some of the circumferentially disposed openings (23) being configured to receive a brake piston (26), and a frame (12) embedded in the composite body (14) and formed from a material different than the matrix. Also a method of forming such a brake piston housing.

Abstract: The exposure of components to high-pressure fluids can result in the application of high tensile stresses to those components, which may lead to reduced life. The preload system described herein helps to reduce the magnitude of those tensile stresses by providing a body and a plug. The body includes a first bore and a second bore. The first bore is configured to be exposed to high tensile stresses. The second bore includes a first engagement structure and a bottom surface near a first portion of the first bore. The plug includes a second engagement structure and a first end. The second engagement structure engages the first engagement structure to force the first end of the plug against the bottom surface of the bore. The force of the plug against the bottom surface of the bore applies a compressive preload to the first portion of the first bore.

Abstract: Each of two members to be fastened has a connecting surface, a communication groove opening on the connecting surface, and an engagement groove communicating with the communication groove and having an engagement surface parallel to the connecting surface. A fastening assembly has a connecting portion and two engaging pieces, each engaging piece having a fastening surface. The two members are placed with the connecting surfaces opposed, so that the engagement grooves are in communication each with the other through the communication grooves. The fastening assembly is inserted into the engagement grooves and the communication grooves, and the connecting portion is operated to draw together the two engaging pieces, causing the fastening surfaces of the engaging pieces to press upon the engagement surfaces of the engagement grooves, thereby clamping the two members together through their opposed connecting surfaces.

Abstract: A cylinder unit for mounting on a machine for the deformation of workpieces includes a cylinder block and a pressure plate which is arranged on the surface of the cylinder block which faces away from the fastening surface, wherein a plurality of pistons each having a spherically shaped head are mounted in the cylinder block. Mounted on each spherically shaped head of the pistons is a pressure piece which protrudes into a bore of the pressure plate and has a recess corresponding to the spherically shaped head of the pistons. A gap is provided between the outer diameter of the pressure piece and the inner diameter of the bore in the pressure plate. A pressure disc is arranged between the pressure piece and the pressure plate in the bottom of the bore of the pressure plate.

Abstract: A telescopic lifting assembly designed particularly for the hydraulic height adjustment of a medical treatment table includes two antiparallel juxtaposed linear drives (2, 3) connected functionally one behind the other in the direction of actuation (1) whereby the inner components (6) are connected to a coupling piece (7) which is provided with guide surfaces (14) cooperating with the outer components (5) in the direction of actuation (1). A secure and stable guiding mechanism is made possible thereby along the entire lifting range.

Abstract: A fluid actuator configured for achieving extended cycle life and reduced overall actuator height. The actuator may include a nesting arrangement between portions of the actuator to reduce overall height and provide stability. The actuator may also join movable members and include a guidance mechanism to avoid undesired contact between actuator portions.

Abstract: Disclosed is a cylinder protective apparatus for preventing strange noise in which an impact damper is fixed to an inner side of a cylinder cover to prevent collision between the cylinder cover and a cylinder or a cylinder guide from occurring, which may be caused by vibration generated when a heavy construction equipment such as an excavator works. Since the cylinder protective apparatus is provided with the impact damper, strange noise due to a gap generated between the cylinder cover and the cylinder or the cylinder guide can be prevented from occurring.

Abstract: A hydraulic actuator assembly comprises a pair of hydraulic actuators having cylinders, pistons, and piston rods that are ganged together for extension of their respective piston rods in longitudinally opposite directions wherein at least one of the actuators comprises an anti-rotation mechanism that prevents rotation of the actuator assembly about its longitudinal axis. The anti-rotation mechanism comprises an axial anti-rotation rod rigidly attached to a cylinder having a non-circular cross-section slidably complementary to a non-circular aperture in a hollow piston rod. The piston rod can travel longitudinally along the anti-rotation rod, but is prevented from rotating by the non-circular cross-section.

Abstract: A pair of zero-turn, hydrostatic transaxles (HZTs) that may be joined to form an integrated, zero-turn, hydrostatic transaxle. Each of the hydrostatic transaxles are further comprised of a casing carrying a hydraulic pump driven by an input shaft, a hydraulic motor driven by a the hydraulic pump through porting contained within a center section, and an axle shaft driven by the hydraulic motor. The hydrostatic transaxles are joined along an interface extending generally perpendicularly to the axle shafts.

Abstract: A two-cycle hot-gas engine comprising an expansion piston in a heatable cylinder member and a compression piston in a coolable cylinder member. The expansion piston and the compression piston are disposed along a common axis.

Abstract: A center section for a hydraulic pump and motor mounted in a transaxle casing. The center section has a protuberance formed thereon, a pair of flat surfaces separate from the protuberance and at least one fastener opening formed in the center section for receiving a fastener engaged to the casing. The protuberance is adapted to mate with a center section locator formed in the casing to establish an X-Y orientation for a central axis while the fastener provides a Z-axis locator for the center section.

Abstract: A reciprocating compressor that includes a cylinder block with a plurality of cylinder bores. A piston is positioned in each bore. Each piston is mounted to move in response to the a crankshaft, causing each piston to reciprocate within the cylinder bore. The compressor further includes a cylinder head which includes bores corresponding to the bores in the cylinder block. The cylinder head includes a suction port in fluid communication with a source of compressible gas and a plurality of suction plenum in the cylinder head. Protrusions or ribs extend into the suction plenum. The cylinder head also includes a discharge plenum in communication with the outlet ports of the valve plate Interposed between the cylinder head and the cylinder block is a valve plate assembly having a discharge valve, and a discharge valve retainer having a pair of radii assembled to the valve plate by snap fitting a cylinder head gasket over the discharge valve and retainer.

Abstract: A pair of substantially mirror image, zero-turn, hydrostatic transaxles (HZTs) that may be joined to form an integrated, zero-turn, hydrostatic transaxle. The control arm and brake mechanism associated with the HZTs can be mounted on either the inboard or outboard side of the HZT casing. In one embodiment, an integrated, inboard brake mechanism is provided for the joined HZTs.

Abstract: This engine 1 relies on a flywheel having a flywheel axis and an undulating cam surface. A piston with a roller at its base is positioned in a cylinder such that the roller abuts the undulating cam surface at some radial distance from the flywheel axis. Thus, as the piston is pushed downward by combustion pressure in the cylinder, it pushes against the cam surface causing the flywheel to rotate. As the flywheel continues to rotate its undulating surface pushes the piston back into position for a repetition of the cycle. The cam surface is configured to control at least one engine parameter such as compression ratio, duration of intake stroke, duration of exhaust stroke, duration of combustion stroke, duration of power stroke, compression stroke pattern, volumetric efficiency, or power stroke pattern.

Abstract: A pump, particularly a plunger pump, comprises a crank mechanism oscillating a plunger in a housing and an elastic sealing device fastened to the plunger. The sealing device provides a pressure-tight sealing with respect to a lower housing space containing the crank mechanism. As a result, an intermediate space in the housing may be filled with air. The intermediate space is hermetically separated from the lower housing space containing the crank mechanism.

Abstract: This engine 1 relies on a flywheel having a flywheel axis and an undulating cam surface. A piston with a roller at its base is positioned in a cylinder such that the roller abuts the undulating cam surface at some radial distance from the flywheel axis. Thus, as the piston is pushed downward by an explosion in the cylinder, it pushes against the cam surface causing the flywheel to rotate. As the flywheel continues to rotate its undulating surface pushes the piston back into position for a repetition of the cycle. More complex embodiments include one in which undulating surfaces are located on opposite faces of the same flywheel with separate pistons interacting with each face and one in which undulating surfaces are located on the facing surfaces of two separate flywheels with pistons positioned between the flywheels. In the latter embodiment, pistons can share the same cylinder.

Abstract: An aggregate (10′) of pressure medium cylinders (11′, 12′) are used especially where there is required a relatively large length of stroke. At least a first (11′) and at least a second (12′) pressure medium cylinder are arranged by the side of each other with their longitudinal axes (11a, 11b) extending mutually parallel. The cylinder parts (13′, 14′) of the cylinders are rigidly connected to each other at least in pairs. Piston rods (17′, 18′) of said first and second cylinders are turned respectively in pairs in mutually opposite axial directions.

Abstract: A pump, particularly a plunger pump, comprises a crank mechanism oscillating a plunger in a housing and an elastic sealing device fastened to the plunger. The sealing device provides a pressure-tight sealing with respect to a lower housing space containing the crank mechanism. As a result, an intermediate space in the housing may be filled with air. The intermediate space is hermetically separated from the lower housing space containing the crank mechanism.

Abstract: A mounting assembly for mounting a pump to a fluid cylinder comprising a tie rod threaded at one end and providing a second end drivingly engageable with a sleeve-like threaded connection for clamping attachment directly into the cylinder block by the direct thread engagement of the connector internally of the cylinder block. The invention eliminates the requirement of machining a fluid cylinder block to provide engageable flanges and form nut pockets, thereby minimizing fabrication time and costs, while increasing strength, stability and alignment accuracy between pump pony rods and plunger assemblies of fluid cylinders generally of the type used for high pressure industrial applications.

Abstract: Mounting grooves 31a for a position sensor are respectively formed in a first face 20a and a second face 20b facing each other of a casing 20, a fixing hole 35a passing through the casing between the opposite faces is formed in a position which overlaps the mounting grooves 31a, a tubular washer member 37 having therein an annular flange 37b for forming a seat for a bolt is housed in the fixing hole 35a such that the washer member 37 can be moved to a first face 20a side and a second face 20b side, and the washer member 37 has such an axial length that the washer member 37 and the bolt head 36a do not interfere with the mounting groove 31a positioned in the face on the other side when the washer member has moved to any one of the opposite face sides.

Abstract: A positive displacement type pump used for applications such as pressurizing beverage dispensing containers, filling fire extinguishers, and pressuring welding tanks. CO.sub.2 or similar fluids are drawn into and discharged through the pump by a reciprocating piston driven by a rotating eccentric main bearing mounted on a bearing frame. The bearing frame comprises an open, unsealed pair of structural plates connected by tie rods, the main bearing itself being sealed by one of two seal arrangements to make it easily convertible between oil-lubricated and oil-free operation. For oil-lubricated operation, the main bearing is supplied with a surrounding sealed bearing sleeve compressed between the plates of the bearing frame. For oil-free operation, the main bearing is internally sealed. The main bearing is driven by a shaft supported on bearings in the plates, the bearings also being changeable between sealed and unsealed bearings for oil-free and oil-lubricated operations, respectively.

Abstract: Brake actuator housings (120) are provided with mounting studs (105, 125) which are spaced from each other a standard predetermined distance so that smaller brake actuators can be mounted to a bracket (5) on a vehicle by way of the same apertures (108) as larger brake actuators.

Abstract: A durable oil well pump having fitted ceramic cylinders. Two metal retainers are fitted at two ends of the ceramic liner barrels. A cement or adhesive, which is resistant to pressure and temperature is placed in the annular clearance among the liner barrels, the retainers and an outer tube. There are multiple segmented plunger skirt and ceramic barrels to be fitted around a plunger inner tube. The valve seat outer ring is shrunk on to the ceramic inner ring. The valve ball is also made of ceramic. This pump has resistance to corrosion, temperature and magnetic fields. This pump can prevent liner barrel displacement, increase the period between repair, improve oil production, and reduce the cost of production.

Abstract: A linear actuator comprising a guide section formed along a longitudinal direction to protrude on a bottom surface of a slide table, a pair of guide blocks formed mutually opposingly and seperated from each other by a predetermined spacing distance on an upper surface of the main cylinder body, attachment holes for attaching the main cylinder body to another member in any direction of attachment from a side of the slide table or from a side of the main cylinder body, and an adjuster bolt for adjusting an amount of displacement of the slide table.

Abstract: Piston rods are coupled to respective pistons movably disposed respective cylinder chambers defined in a cylinder body. The piston rods have distal ends connected to an end plate mounted on a slide table which is mounted for movement along a guide rail. When the piston rods are displaced by the pistons, the slide table is also displaced axially of the cylinder body. When the slide table is positioned at either end of its stroke, a load is applied by the weight of a workpiece supported on the slide table and the weight of the slide table itself to the cylinder body through the guide rail. The slide table is thus prevented from being unduly flexed under the load. The length of the slide table can be set to a desired length irrespective of an increase in the displacement of the slide table. Even if the displacement of the slide table is increased, the slide table is not flexed and hence remains highly rigid against flexure.

Abstract: An air pump includes two operating rods slidably engaged in two cylinders and having an upper end extended outward of the cylinders. A block is secured to the upper ends of the operating rods. A coupler is rotatably secured to the upper portion of the block by a bolt. A hand grip includes a chamber for engaging with the coupler and is pivotally coupled to the coupler at a pivot shaft. The pivot shaft is perpendicular to the bolt so as to allow the hand grip rotating to a folded position.

Abstract: A dual-piston pump apparatus includes a pair of reciprocating sleeves within which a pair of reciprocating pistons are disposed. The pistons and sleeves are each supported on a frame for independent reciprocating movement along a line angled relative to horizontal by an angle of less than about 60.degree.. The apparatus also includes a piston construction including a removable face which permits the piston to be broken down for cleaning. Each piston is normally restricted by a stop from extension beyond the end of the corresponding sleeve, but an actuator is provided for freeing the piston relative to the sleeve so that the piston may be extended beyond the sleeve and the sleeve may be withdrawn from a pump chamber of the apparatus.

Abstract: A cylinder having a piston assembly capable of stopping once when having moved up and down every time including a housing having a cavity, a gear ring fixedly within the cavity of the housing, a main crankshaft fitted within the cavity of the housing and provided with an eccentric recess, a gear meshed with said gear ring, an auxiliary crankshaft including an upper axle and a lower axle, the upper axle being connected with a piston assembly via connecting rod and having a center tangent to a pitch circle of the gear, the lower axle being pivotally connected with the eccentric recess of the main crankshaft, the gear meshed with the gear ring and fixedly mounted on the lower axle of the auxiliary crankshaft and having gear ratio of 2:3 to the gear ring.

Abstract: An array of symmetrically disposed piston-cylinder assemblies may be utilized to produce oppositely directed movements along a single force axis. Plumbing between the various cylinders may be external or internal, or a combination thereof, the exact form depending upon the particular embodiment. The array may be fabricated as a unitized inter/plumbing configuration or from separate cylinders that are functionally retained about an inter/plumbing fixture.

Abstract: In a slide actuator, a central guide rail having V-shaped grooves defined therein and opened at 90 degree angles, is mounted on a cylinder body. A slide table is brought into engagement with the guide rail. Guide members having V-shaped grooves defined therein are provided inside the slide table so that they are opposed to the grooves defined in the guide rail. Cylindrical roller bearings are alternately fitted at inclinations of 90.degree. in their corresponding channels defined by the opposed grooves. Thus, when the roller bearings are rolled, the slide table is displaced with higher accuracy and a load supported by the slide table is transmitted to the guide rail from the roller bearings.

Abstract: A compact hydraulic cylinder for use in a recess of a sliding door of a waste processing system. The cylinder includes a housing containing a first cylinder rod extending from one end of the housing and second and third rods extending from an opposite end of the housing and spaced apart such that the first rod is located between the second and third rods. The first cylinder rod is adapted to be connected to a fixed mounting bracket located on the waste processing system and the second and third cylinder rods are adapted to be connected to a removable mount. The removable mount is also located in the recess and is adapted to be connected to the door such that the mount and cylinder assembly can be accessed from the rear of the door without having to disassemble the door.

Abstract: A rodless cylinder for feeding a workpiece has a cylinder having a cylinder tube with a bore defined therein and a piston reciprocally movably disposed in the bore. The cylinder tube has a slit defined therein and extending longitudinally therealong, the slit communicating between the bore and an exterior space. The slit is closed by a first seal member engaging the piston and a second seal member engaging a slide table. The piston has a separator separating the first and second seal members from each other. The cylinder tube has a pair of slanted first surfaces positioned one on each side of the slit. A pair of slide members is disposed on the slide table and have respective second surfaces engaging the first surfaces, respectively, for guiding the slide table when the piston reciprocally moves in the bore and bearing a load applied to the slide table.

Abstract: A linear movable apparatus for imparting rotational movement to a turntable is provided. The turntable is secured to a rotatably mounted shaft having a ring gear thereon for meshed engagement with gear teeth provided on a piston rod which extends between a pair of pistons. Each piston is reciprocally carried in aligned cylinder housings mounted in a support structure. An adjustable mechanism is provided for retaining the piston rod in snug-fitting relation with the ring gear, and a bracket assembly is secured around the ring gear to support the adjustable mechanism against the ring gear.

Abstract: A sealed vehicle wet disc brake has a brake housing and a piston housing which are fixedly interconnected and which receive a rotor. The two housings and rotor define an annular cavity which is sealed by appropriate rotary seals and in which is maintained a friction stack. The piston housing has a plurality of uniformly spaced piston bores therein, such bores being interconnected by an annular groove which circumferentially intersects with a circumferential surface of the piston housing. A pressure source of fluid communicates with the annular groove and the piston received within the bores. The annular groove is sealed by means of an "O" ring engaged therein from the circumferential surface and retained by a retaining ring. The intersection of the annular groove with the circumferential surface is tapered to accommodate compressive retention of the "O" ring.

Abstract: A bicycle tire pump includes a cylinder having two passages defined therethrough which are separated by a board, two openings respectively defined in a top of the cylinder and communicating with the two passages into which two pistons are respectively and movably received. A head is mounted to the top of the cylinder and has two ways defined therein which respectively communicate with the two passages in the cylinder and an outlet of the head. A bolt extends through one of the two passages and is threadedly connected to the head. The bolt has a longitudinal passage defined therethrough which communicates with one of the two ways.