Abstract: A trim-tilt device for a marine propulsion device includes a piston having a valve device for stopping a trim action by bringing a piston-side chamber and a rod-side chamber into communication with each other at an end of a trim region before a propeller of the marine propulsion device rises higher than the surface of the water when the marine propulsion device is generating a propulsive force.
Abstract: A piston (3) for a hydraulic dashpot for motor vehicles, mounted on one end of a piston rod (1) and dividing a cylinder (5) into a two compartments (6 & 7), with two groups of lines (8 & 9) arranged more or less in concentric circles and more or less paralleling the piston rod and conveying hydraulic fluid in opposite directions, and with disk-shaped check valves, to some extent in the form of stacks (15 & 26) of cup springs, at each end that block one group of lines in one direction at a time, whereby the valve that blocks the inner lines (8) comprises either two separated springs (11), one above the other, or a stack (15) of springs, whereby the springs or stack nearer the outlet (10) from the inner lines maintain or maintains one cross-section open for the fluid to flow through, and whereby, when the pressure of the fluid increases, the spring or stack at the other end opens another cross-section for the fluid to flow through and the valve that blocks the outer lines opens intakes into the inner lines.
Abstract: A self-aligning steering system for a vehicle having a steering wheel and a plurality of front wheels. The invention has a hydraulic fluid circulation means responsive to the steering wheel and a left and a right hydraulic cylinder for maneuvering the front wheels in response to the hydraulic fluid circulation system. The hydraulic cylinders have an internal fluid release system such that the volume of hydraulic fluid in the left and the right hydraulic cylinders is equalized through the hydraulic fluid circulation means. Equal hydraulic fluid volume ensures that the front wheels are in alignment.
Abstract: A fuel injection system for injecting gasoline or other fuel directly into the combustion chambers of an internal combustion engine including a fuel pump with a plurality of fuel pumping pistons mounted within cylinders formed in a fixed barrel member. Each of the pistons internally contains an improved inlet valving assembly mounted wholly within a bore axially extending in the piston. The valving assembly provides a one-way fluid inletting to the pumping chamber by slight movement of a low mass valving member away from an annular seating surface formed about an inlet passage. Unlike rotary sliding type valves, the subject valve does not move rapidly through and agitate fuel and thereby does not generate any significant degree of undesirable fuel heating thus preventing undesirable fuel vaporization which is detrimental to pumping action of fluid.
Abstract: In a power tilt cylinder device 100, a hydraulic fluid is supplied to the opposite piston side space 22B of a free piston 25, in the upper limit position of upward tilting, which is performed for discharging the hydraulic fluid from the first chamber 21, an operation valve 62 is pushed open by a rod guide 18A, and a flow passage 64 directed from the opposite piston side space 22B of the free piston 25 toward the first chamber 21 is caused to be conductive via a check valve 61 and the operation valve 62.
Abstract: A piston assembly that is movable back and forth parallel to its axis in a cylindrical housing, comprising a piston-like support part made of a hard material and a guide ring made of a polymer. The guide ring surrounds the support part along a portion of the axial length of the piston. The support part and the guide ring are joined to each other via frictional and/or form locking provided by mating between grooves on the support part and a corresponding number of radial projections on the guide ring. A set of axially spaced apart sealing lips, integrally molded with the guide ring, extends axially beyond the grooves to provide a seal with respect to the cylinder wall.
Abstract: A forming die set has one or more independently operated hydraulic actuator assemblies mounted directly in one of the die shoes to enable a programmed piercing pattern to be carried out at the time the workpiece is formed. Each actuator assembly includes a compact self contained actuator, in which both a piston and piston rod and a punch retainer are slidable in different sections of a housing bore with supply and return connections both through an end cap of the cylinder housing with a return flow path through a tube extending through the piston. The piston rod extends through an annular rod gland member positioned in the cylinder housing bore, and has an end protruding through to a punch retainer to which it is coupled. The punch retainer is slidable in a section of the cylinder housing bore. A purging system using a check valve in the supply line establishes an incremental flow back to the reservoir eliminate air bubbles.
Abstract: Disclosed is an actuating plunger of an electromagnetic pump, the actuating plunger having a good magnetic characteristic so as to improve the operational efficiency of the electromagnetic pump and reduce the vibration and the operational noise due to the actuating plunger. The actuating plunger has a plunger head made by a high-temperature sintering. The plunger head has a cylindrical side wall, and a plurality of shoulders protruding inwards from a lower end of the cylindrical side wall. A piston is fixedly fitted in the middle of the shoulders. The piston extends downwards so as to be slidably fitted in a second cylinder.
Abstract: An improved pressure control apparatus for a stirling module capable of controlling a pressure between compression space and a bounce space by providing an improved pressure control apparatus, so that a high speed operation of a stirling module can be obtained, which includes a piston including a plurality of pressure control hole groups vertically extended within the piston for connecting between the compression space and the bounce space, each of groups consists of at least one hole; a pressure control member supporting section having a diameter smaller than that of the piston and upwardly extended from the top of the piston; a support member engaging section having a diameter smaller than that of the pressure control member supporting section and upwardly extended from the top of the support member engaging section; and a pressure control member including an engaging section threadly engaged to the pressure control member supporting section and an opening/closing section having a plurality of wings.
Abstract: A compressor assembly is disclosed including a compressor mechanism mounted within a hermetically sealed housing. A cylinder block contains a reciprocating piston having a suction valve assembly. The piston includes a head with a deep semitorus shaped annular groove with a similarly shaped solid suction valve that seats thereto. A retaining mechanism including a clamping bolt with a plurality of radially extending fingers is used to reduce valve inertia and impact forces. The fingers behave as cantilevered beam springs.
Abstract: A fluid-operated brake actuator having a check valve in the spring chamber to equalize the pressure on opposite sides of an operating movable diaphragm. The brake actuator comprises a service brake housing divided into first and second service chambers by a diaphragm or piston, and a spring brake housing arranged in tandem with and attached to the service brake housing, also divided into a first and second spring chambers by a diaphragm or piston. The check valve connecting the first and second spring chambers blocks flow between the first and second chambers when the second spring brake chamber is pressurized and opens up flow between the two chambers when the second spring chamber is depressurized.
March 15, 1994
Date of Patent:
October 24, 1995
NAI Anchorlok, Inc.
Wiliam C. Pierce, John P. Smith, Steven Stojic
Abstract: A double acting reciprocating intensifier uses a single low pressure fluid stream as both the power supply and the source of fluid the pressure of which is to be intensified. The entire device, including flow paths, is confined within a compact cylindrical housing. Tandem drive pistons minimize operating frequency, while maximizing intensification ratio and output volume flowrate. Placement of both high pressure cylinders downstream of the drive cylinders permits simple routing of flows through the centers of the low and high pressure pistons. A check valve connected between the high pressure pistons eliminates one of the four high pressure check valves required in the prior art. A single reciprocating valve, whose state is determined by drive and high pressure piston position, coordinates all of the drive side flows. Various components perform multiple functions to permit the compact shape.
Abstract: A relief valve for a hydraulic piston consists of a tubular mid-section with closed ends and circular stops at each end. The tubular center section has cross ports at each end that run perpendicularly to the axis of the valve. The cross parts are situated as close to the end stops as possible. The cross ports intersect the hollow center of the spool and allow hydraulic oil to flow through the piston via the passageway in the center of the valve when the valve is in the open position.
Abstract: An ejection pump apparatus of a torpedo launching system is provided with improved water piston which is more stable during use and which enables the intake end of the water cylinder and the sea valve to have a smaller diameter than that of the piston. In order to assemble the piston through the smaller diameter opening, the piston is segmented into four pie-shaped segments which are assembled together in adjacent relation with bolt fasteners that extend through the sidewalls of the segments. The outer wall of the piston includes a circumferential slot which divides the outer wall into two spaced bearing lands which provide the piston with more stability. The circumferential slot also enable water to flow through the sidewall of the piston into the piston and outwardly through an open top thereof.
January 14, 1994
Date of Patent:
June 6, 1995
The United States of America as represented by the Secretary of the Navy
Abstract: In an artificial leg for a person having an upper thigh cut and a knee joint lost, a cylinder disposed between upper and lower leg members, which are coupled through a pivotable joint, for controlling bending and straightening of the joint by an air cushion for convenience of walking. The cylinder includes a cylindrical sleeve closed at both ends and a piston having a piston rod and sliding in the sleeve, and has its structure improved by using as a cushion one of two inner cavities separated by the piston, which encloses the piston rod, thereby buffering butting between the upper and lower leg members to remove unpleasant shock resulting at the end of straightening the joint.
Abstract: A passive compressor is disclosed which includes a free piston or a flexible membrane whose movement is controlled by pressure variations in a main chamber. The pressure in the main chamber changes according to the pressure in the motor crankcase, as the main chamber is coupled to the crankcase by a crankcase transfer passage duct.As the free piston or flexible membrane moves towards the main chamber, it causes a pressure decrease in the air chamber which subsequently admits external air through an inlet valve. When the free piston or the flexible membrane moves in the direction of the air chamber, the increased pressure on the piston or membrane forces the external air into the motor cylinder, through an air transfer passage duct, and towards a port on the cylinder that is opened due to the position of the motor piston. The inlet valve prevents the loss of pressure in the air chamber. Alternatively, the main chamber may be directly attached to the motor crankcase.
Abstract: A reciprocating pneumatic motor for hydraulics has a pair of guide grooves on the inner wall of a cylinder provided, together with a pneumatic piston and a shuttle valve to function pneumatically. The piston has a seal ring which passes the guide grooves to allow air to flow into the shuttle compression chamber, pushing the shuttle valve and opening up a channel for the venting of air. This continuous air flow and venting causes the piston to reciprocate. In addition, the piston is integrated with a ring plate using plastic ultrasound technology which simplifies the structure of the pneumatic motor.
Abstract: A reduce waiting time drilling jar 1 includes a mandrel 2, a housing 3 telescopingly positioned about the mandrel 2, and first and second pistons 89, 111 positioned axially between the mandrel 2 and the housing 3. The pistons 89, 111 are spaced longitudinally apart, forming a substantially sealed chamber 88 therebetween. The first piston 89 has a first and second substantially parallel flow passage 94, 200 formed therein and extending longitudinally therethrough to provide first and second flow characteristics. A valve 204 is hydraulically connected to the second flow passage 200. The valve 204 is translatable between first and second operating positions, wherein fluid flows relatively freely through the second flow passage 200 in the first operating position, but is restricted in the second operating position.
Abstract: A device for controlling a pneumatic cylinder device, being of a double cylinder construction comprising an outer cylinder and an inner cylinder sealably fitted in the outer cylinder to slide along the outer cylinder. In the inner cylinder, a piston with a valve at one side thereof or valves at both sides thereof is slidably disposed. To control the valve or valves, an adjusting rod is provided which is slidably and rotatably disposed in the piston and its piston rod and adjusted by an operating lever. Alternatively, the double cylinder construction comprises a pair of cylinders disposed axially in parallel to each other. In the cylinders, pistons are disposed, one of which has a valve at one side thereof or valves at both sides thereof. The cylinders are communicated with each other by a communication construction having a communication adjusting groove and an adjusting lever for adjusting the communication area of communication adjusting groove.
Abstract: The invention relates to a reciprocating hydraulic motor having a differential piston interposed between an inlet pipe for fluid at a pressure P1 and an exhaust pipe for fluid at a pressure P2 which is less than the pressure P1 The moving assembly constituted by the different-section pistons that slide in a stepped cylinder includes a flap having two positions and controlling three ports, the flap being mounted to pivot about an axis. In each of its positions, the flap bears against two wall portions disposed on opposite sides of the flap and at different distances from the pivot axis so that the effect of the pressures P1 and P2 on the faces of the flap is to establish a positive closure torque.
Abstract: A shock-absorbing piston, a blank for the piston and a method for producing the piston include two parts being constructed radially symmetrically, but formed with outer and inner parts differing from each other. This offers great variability in the shaping of the functionally essential elements of the shock-absorbing piston.
Abstract: A magnetically actuated fluid motor has a shiftable member having valve members for alternately closing one and opening the other of large and smaller faces of a stepped piston reciprocating in a housing. The shiftable member carries a magnet and is shiftable to collocate the magnet with one of spaced apart magnet attractors. A magnetic holding force between the magnet and attractors exceeds a simultaneous resilient counterforce supplied by spring members operating on the shiftable member. When the magnetic holding force is weakened by application of a separating force to separate the magnet from an attractor, stored energy in the compressed springs is released to shift the shiftable member. Separating force is applied through stops which arrest the shiftable member while the piston continues to move, without immediately opening the closed face of the stepped piston.
Abstract: A regenerative hydraulic cylinder has a piston dividing its interior into a pair of chambers. A rod extends from the piston through a cylinder end wall. Several axial passages in the piston extend between opposite piston faces. A valve member is mounted over one piston face and has a sleeve that slides axially in a recess formed in the one piston face. Springs urge the valve member to a flow-impeding orientation against the piston face. A hydraulic pilot line in the rod, accessible at an external rod end, permits the valve member to be displaced away from the piston face to a flow-enabling orientation. The valve state is controlled to permit fluid flow directly between chambers during extension or contraction of the cylinder.
Abstract: A force applicator comprises a ram operable by fluid under pressure. A pressure pad (7) is located between one movable part of the ram (3) and the load (9) and means are provided which enable relative movement to take place between the pressure pad and the ram in a direction at right angles to the direction of operation of the ram. The means may take the form of a fluid chamber (15) between the pressure pad and the ram or a disc of PTFE between them.
Abstract: The dispensing cartridge comprises a storage cylinder and a dispensing piston whose bottom surface is progressively recessed from the piston edge towards an aeration bore. An overflow chamber is disposed around said aeration bore, overflow slots being provided in the wall which forms said aeration bore. Said aeration bore is sealed by a closure whose peg portion extends into said bore and whose head is provided with a surrounding bead which snaps into a corresponding annular groove in the outer wall of said overflow chamber. Such a cartridge prevents a disturbing effect of the material flowing out when the dispensing piston is inserted, and during the aeration procedure.
Abstract: A piston assembly comprising a primary piston and a co-centric secondary piston. The pistons are received within a housing for reciprocating movement therein and relative to each other. The housing and the pistons are arranged for operating pressure to be applied to the secondary piston so as to drive both pistons within the housing. The secondary piston is provided with means enabling the operating pressure to be equalized across the secondary piston and at least one bypass passage extends through the secondary piston. The arrangement is such that upon completion of the stroke of the pistons pressure equalization occurs across the secondary piston which causes the pistons to separate. The bypass passage becomes fully operable subsequent to pressure equalization, whereby a fast return stroke is achieved.
Abstract: A pressure fluid reservoir having at least an approximately vertically disposed cylinder with a displaceably guided divider piston therein. The piston divides a pressure fluid reservoir chamber of the cylinder, located below the piston from a gas chamber located above the piston. The divider piston has a hollow chamber, which is covered with respect to the gas chamber by a cap having an opening. The cap has a fluid seal for lubricating piston sealing rings. A riser pipe that begins at an opening in the cap extends as far as a bottom of the hollow chamber that contains fluid. In an expansion of a gas cushion located in the gas chamber in the riser pipe and in the hollow chamber, fluid is pumped through the riser pipe to the fluid seal, to regenerate it the fluid seal. The pressure fluid reservoir is particularly well suited to vehicle brake systems, where long functional reliability of a piston seal is crucial.
Abstract: The present invention is directed to a mechanical hydraulic pressure dampening devices for use in a steering system of an articulated self-propelled work vehicle. The dampening devices are hydraulically positioned between the steering cylinders of the work vehicle and absorb hydraulic pressure spikes in the steering system. In the preferred embodiment, the pressure dampener comprises a pressure accumulator that is fluidly coupled to the steering cylinder by a shuttle check valve. The shuttle check valve shifts in response to a pressure spike so that it can be absorbed by the pressure accumulator. In a second embodiment, the pressure dampener comprises a cylinder having two pistons that are biased into a normal position by a spring extending between the pistons. Spaces are formed on either side of the pistons and are hydraulically coupled to the steering cylinders. A central space formed between the two pistons is hydraulically coupled to a sump return line.
Abstract: A stroke limiter for a hydraulic cylinder comprises two sleeve portions each having a channel located therein that are frictionally mounted to the piston rod adjacent to the piston. An elongated contactor is slidably received in each of the channels. The contactor is longer than the sleeve portion and extends past the bottom of the sleeve. The top of the sleeve is provided with a cutout portion which is adjacent to the contactor and provides a hydraulic fluid flow path from the piston mounted poppet valves. When the contactor contacts the end cap of the cylinder, the contactor slides upwardly in the sleeve and contacts the poppet valves in the cylinder unseating the valves and creating a hydraulic fluid flow path across the piston.
Abstract: In a rotational working cylinder comprising a shaft arranged concentrically within the working cylinder and driven out of the working cylinder with at least one end of it, a piston being divided into two piston portions perpendicularly to the shaft and the piston portions being held in tensed position in respect to each other, forced trajectories between the working cylinder and the piston portions as well as between the piston portions and the shaft, respectively, at least one of the forced trajectories is formed as a longitudinal spiral path, and the piston portions are locked in relation to each other for maintaining the tensed position of the piston portions in all operational positions and loads of the working cylinder.
Abstract: An apparatus for readjusting first and second adjustable pressure relief poppet valves to vent the fluid pressure moving a piston when the piston is at the ends of a second work stroke which is of a length less than a first work stroke for which the poppet valves are adjusted. Each of the poppet valves is carried by the piston and includes a valve seat and a valve member movable relative to the valve seat. The piston is disposed in a fluid chamber defined by a housing. The piston divides the fluid chamber into first and second chamber portions. One of the chamber portions is pressurized and the other is vented to move the piston in a work stroke. The apparatus includes a member supported by the housing for moving the seat of the second poppet valve outwardly relative to the piston in response to the member moving relative to the housing and engaging the seat of the first poppet valve to move the seat of the first poppet valve inwardly relative to the piston.
Abstract: A hydraulic cylinder is disclosed having a hollow cylinder with a closed first end and an open second end. A rod is positioned in the interior of the hollow cylinder and the rod is securely connected to the first end of the cylinder. The rod is positioned in substantially the center of the hollow cylinder and is substantially parallel to the longitudinal axis of the cylinder. The end of the rod that is spaced apart from the first end of the cylinder has an area of enlarged cross-section. A movable piston having a first end and a second end positioned with the first end of the piston being in the interior of the hollow cylinder. The second end of the piston extends from the open end of the hollow cylinder. The first end of the piston defines a slot for receiving the end of the rod having an enlarged cross-section. The slot is disposed to receive the end of the rod having the enlarged cross-section when the slot and the end of the rod are properly aligned.
Abstract: A sealing ring device is provided for a fluid valve having a piston (2) reciprocating within a cylinder (1), wherein the piston (2) includes a valve cone (2c) adapted to contact a valve seat (11). In order to seal the inner space of the cylinder (1) located behind the piston (2) from an inlet/outlet passageway (A), a resilient sealing ring (5) is disposed in an annular groove (4) opening into the cylinder (1) around the rear end (2a) of the piston (2). A press ring (7), which extends above the rear end (2a) of the piston (2), contains the sealing ring (5) in the annular groove (4). A spring element (8) rests on the press ring (7). A piston rod (3) is guided in slidable manner through the piston (2). A stop (9) is attached to the rod (3) above the rear end (2a) and opposite the top side of the spring element (8).
Abstract: This invention relates to a pump arrangement (54) for use in a linear fluid operated device having a reciprocating piston (14) separating a first active fluid chamber (30) and a second chamber (32) which eliminates the problem associated with fluid leakage buildup developing in the second chamber. The pump arrangement (54) is connected to the reciprocating piston (14) and pumps leakage fluid present in the second chamber (32) from the second chamber (32) and into the first chamber (30) in response to a force of a preselected minimum magnitude being applied to the pump arrangement (54). Thus, the problems of inefficient linear fluid operated device operation, reduced piston stroke length, external fluid leakage, and erratic piston travel speed are eliminated. The pump arrangement (54) is particularly suited for use in a single acting linear hydraulic jack (12) such as used on a material handling vehicle.
Abstract: The plate valve has a housing forming an inlet spigot and an outlet spigot. A movable valve member provided with a closure plate and an orifice plate is movable radially of the spigots via servo-pistons which are rigidly connected to the valve member. The pistons are guided in cylinders disposed diametrically opposite one another on the spigots. The cylinders may be integrally formed with the plate valve housing or may be separably formed as cylinder heads.
Abstract: A closed circuit power system is disclosed herein having a hydraulic power device incorporated therein which includes an input piston and cylinder assemblage and an output piston and cylinder assemblage connected together by a fluid conduit so as to operate in unison. The input assemblage includes a piston moved by an input ram so as to apply a fluid pressure via the conduit to the output assemblage. The output assemblage includes a pair of pistons operating in unison in separate chambers in response to the applied fluid pressure for moving an output shaft. The pair of pistons include pressure faces against which the fluid pressure is applied which are of equal area but different shape. A selected piston of the output assemblage includes conical forward and rearward faces with a corresponding or matching concave recess in the rear cylinder wall.
Abstract: An adjustable dockboard utilizing a gas spring for counterbalancing action. The dockboard includes a ramp hinged at its rear edge to the supporting structure or frame and a lip is hinged to the forward edge of the ramp and is movable between a downwardly hanging pendant position and an extended position. The ramp is counterbalanced to an upwardly inclined position by a gas spring assembly which interconnects the frame and the ramp. The gas spring assembly comprises a closed cylinder-piston structure in which the cylinder contains a gas, such as nitrogen, and a quantity of a liquid, such as oil. When the ramp is in the horizontal position, the piston is retracted in the cylinder and due to the differential in the magnitude of the forces acting on opposite sides of the piston, a biasing action is achieved which urges the piston rod to an extended position and moves the ramp to the upwardly inclined position.
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.
July 22, 1975
Date of Patent:
August 23, 1977
National Research Development Corporation
Abstract: To permit dry operation of a piston within the cylinder, the cylinder is made of metal, and the piston is made of polytetrafluorethylene; the piston, preferably, is formed with an annular ring groove extending downwardly from an end face thereof to leave a circumferential lip, the groove having a spring located therein biasing the lip outwardly against the cylinder wall, to provide for sealing contact of the lip against the cylinder wall, which is additionally reinforced by pressure of the gas being compressed by movement of the piston within the cylinder, tending to expand the lip against the piston surface, at the time when the compression is highest, and sealing is the most desired.
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.