Abstract: A hydraulically operated rotary pipe bending machine has a box (1) from which superiorly protrude a die shaft (2) that is rigidly connected to a die and integral with a die gear (29) being driven by an actuator (30) through a hydraulic circuit and being stopped by a limit switch device (8), and a counter-die unit (3) driven by a handwheel (4) in order to place an elongated piece to be bent against said die. The actuator (30) has a single-acting cylinder, having a piston (31) holding a rack rod (30a) engaging said die gear (29), the piston (31) being opposed in its travel by a return spring (33). The limit switch device (8) has an angularly graduated disc (10) mounted, manually adjustable, on the die shaft (2) and provided with a cam (16) designed to control said limit switch (17) of the hydraulic circuit.

Abstract: A dual drive driveline for a vehicle has a power source, a hydrostatic pump drivingly engaged with the power source, a first axle, a second axle, and a first hydrostatic unit in fluid communication with the hydrostatic pump. The first hydrostatic unit is drivingly engaged or selectively drivingly engaged with the first axle, and the first hydrostatic unit is not drivingly engageable with the second axle. A second hydrostatic unit in fluid communication with the hydrostatic pump, the second hydrostatic unit being drivingly engaged or selectively drivingly engaged with the second axle, and the second hydrostatic unit not being drivingly engageable with the first axle. A control unit is adapted to control a hydraulic displacement of at least one of the hydrostatic pump, the first hydrostatic unit and the second hydrostatic unit.

Abstract: A fluid storage reservoir that creates a regenerative loop inside the reservoir to maintain a pressurized main suction chamber of the hydraulic fluid reservoir is provided. This reservoir includes two separate chambers which are operably fluidly connected by one or more check valves. In the main suction chamber, the design arranges the return flow larger than suction flow in order to pressurize this chamber. This pressure can be adjusted by the check valve setting. This regenerative reservoir can provide sufficient pressure when large system flow occurs.

Abstract: An apparatus for accommodating fluid expansion and contraction within an axle housing or axle support structure of a hydrostatic transaxle is provided. A partitioning element separates the hydraulic fluid from an air chamber created at least partially by the partitioning element and the partitioning element has an internal volume that is in communication with the primary sump and the partitioning element expands to increase the size of its internal volume and thereby expand the volume of the sump.

Abstract: An improved lance pump is disclosed for pumping a pumpable product, particularly lubricant including grease, from a lubricant supply. The pump comprises a head for placement above the supply, a tubular lance structure affixed to the head and extending down into the supply, and a pump tube inside the lance structure that is reciprocated up and down for pumping lubricant from the supply on both upstrokes and downstrokes of the tube. A ram at a lower end of the lance structure is positioned for forcing lubricant up into the tube and past an inlet check valve on a downstroke of the tube.

Abstract: An orientation-independent electro-hydraulic actuator that includes a housing having an interior space forming a fluid reservoir, a pump connected to the housing, an electric motor drivingly coupled to the pump; and a piston-cylinder assembly having a piston axially movable within a cylinder. The cylinder is in fluid communication with the pump to effect movement of the piston in response to fluid flow between the cylinder and the fluid reservoir. The pump has one or more inlet/outlet ports communicating with a volumetric centroid region of the fluid reservoir. The fluid reservoir includes a volume of hydraulic fluid such that when the piston is fully extended, the volume of fluid in the reservoir is at a minimum and at least one of the inlet/outlet ports is submerged in hydraulic fluid.

Abstract: A hydraulic linear actuator system known as the “Dynaco Stepper Pump Hydraulics System” is which is an electrically driven hydraulic pump system made of durable materials for use in an electronically controllable hydraulic system comprised of: (a) an electrically driven stepper motor; (b) a hydraulic pump to pressurize a hydraulic fluid; (c) a means to connect the stepper motor to the hydraulic pump; (d) a pressurized reservoir for a quantity of hydraulic fluid; (e) a means to supply pressurized fluid to a hydraulic actuator; (f) the hydraulic actuator with a means to provide linear motion to an object; (g) the means to provide linear motion to an object; (h) a means to return lowered pressurized fluid to the reservoir. An alternative embodiment is further comprised of a controller with a series of feedback signals.

Abstract: A fluid-pressure pump 2 rotated by an electric motor 9 drives a fluid-pressure cylinder 3. A discharge flow restrictor 15 is provided in a discharge passage 12 through which a working fluid from the fluid-pressure pump 2 is supplied to fluid-pressure cylinder 3. A pilot-pressure-operated shut-off valve 4 changes over a connecting position A at which the discharge passage 12 between the discharge flow restrictor 15 and the fluid-pressure cylinder 3 is connected to the tank 10 and a shut-off position B at which the discharge passage 12 is disconnected from the tank 10, in response to a pressure P1 in the discharge passage 12 between the discharge flow restrictor 15 and the discharge port 24, thereby enabling a change-over between a loaded mode and an unloaded mode assumed at an fluid-pressure actuator unit 1 in response to an operation of the fluid-pressure pump 2.

Abstract: A hydraulic system, especially in a high-pressure application, comprises a pressurized-fluid tank, a pressurized-fluid pump driven by a drive unit, at least one hydraulic load that can be pressurized thereby and a control and/or distribution unit connected fluidically between the pressurized-fluid pump and the load. This unit is provided with a housing and a core received therein and connected rigidly with the housing, which core bears with part of its surface in the region of a common, closed, especially cylindrical joint face with the housing on a corresponding inside face of a housing opening. Surface groove-like flow ducts are provided on the core and/or the housing in the region of the joint face, and the pressurized-fluid pump is directly built onto the control and/or distribution unit in the region of a free end face of the core.

Abstract: In pneumatic non-load quick dual-speed hydraulic jack, the small of piston ring (17) of hydraulic pump cylinder integrates with pump body (19) and external ring of step pump core (14) to form movable assembly. The middle part of step pump core (14) is provided with pump core step interface (8) used for conversion of hydraulic speed. The step hole on the same axis of pneumatic valve block on special pneumatic valve structure is provided with washer (48), button (49), pneumatic valve core (45), compressed spring (68) and valve core fastness set. The pneumatic valve parts can replace the hydraulic quick pump structure partially when the high-pressure air source is available. High-pressure air delivered to the oil reservoir of the external sleeve (4) presses the hydraulic oil into the oil chamber of oil cylinder, and thus facilitates the quick lift of jack piston under light load or empty load.

Abstract: A hydraulic drive system realizes a jack-up operation without arrangement of a flow rate control valve and center bypass selector valve. The hydraulic drive system has first and second hydraulic pumps, first and second directional control valves for controlling boom cylinders, a third directional control valve for controlling the boom cylinders, and a third hydraulic pump for feeding pressure oil to the third directional control valve. A jack-up selector valve has a second select position where, when a pressure in bottom chambers of the boom cylinders is not higher than a predetermined pressure, feeding of pressure oil, which is delivered from the first hydraulic pump and second hydraulic pump, to rod chambers of the boom cylinders, is held permissible in association with switching of the second directional control valve and third directional control valve by a manipulation of a control device.

Abstract: A hydraulic circuit of a servo-assisted mechanical transmission, which is provided with a number of hydraulic actuators provided with corresponding actuation chambers adapted to be filled with pressurized oil; the hydraulic circuit is provided with: a number of solenoid valves, each of which is coupled to a corresponding actuation chamber of a hydraulic actuator; a tank, which contains the oil at atmospheric pressure and is provided with an upper loading aperture; the cap, which closes the loading aperture of the tank and is provided with a through venting hole which puts the tank into communication with the external environment; a filtering element, which is coupled to the cap and is arranged under the venting hole; a hydraulic accumulator containing the pressurized oil; and an electric pump which draws from the tank and feeds the hydraulic accumulator.

Abstract: A clutch operating system includes a clutch pedal; a clutch master cylinder that generates hydraulic pressure by operation of the clutch pedal; a clutch release cylinder that operates the clutch by the hydraulic pressure; and a clutch fluid reservoir that stores fluid. The clutch master cylinder includes a cylinder with a wide section, an intermediate section, and a narrow section; a piston in the cylinder, with an intermediate section that fits in the intermediate cylinder section, and a narrow section that fits in the narrow cylinder section; a reservoir fluid line fluidly communicating the clutch fluid reservoir and the clutch master cylinder; an operating fluid line fluidly communicating the clutch release cylinder and the clutch master cylinder; a return spring providing a restoring force to the piston; and a piston rod that delivers movement of a clutch pedal to the piston.

Abstract: The invention relates to a hydraulic fluid accumulator (30) having a high-pressure chamber (32) and a low-pressure chamber (33), wherein the high-pressure chamber (32) provided with an equalizing volume (36) is disposed in the low-pressure chamber (33). Provided at the hydraulic fluid accumulator (30) is an external connection (34) for the equalizing volume (36), by means of which connection the equalizing volume (36) can be filled with a gas having a predefinable pressure.

Abstract: An actuator with a simple function for the control of a friction clutch in the drive train of a motor vehicle having a cylinder/piston unit for generating the contact pressure of the clutch should be fast, inherently safe and nevertheless simple and inexpensive. For this purpose, a controllable pump (3) generates a pressure medium and makes it available to the cylinder/piston unit (1) via a self-regulating valve unit (2). A dump valve (8) consists of a sleeve (10) and a spring-assisted slide (12) therein. The sleeve has a first opening (11), through which the pressure medium can flow from the cylinder/piston unit (1). The slide (12) exposes the opening (11) in a first position and conceals the opening of a second position. The clutch is controlled in this way by actuating the electric motor.

Abstract: A ventilation valve of a hydraulic jack is dedicated to be mounted at an outer wall of an oil storage tank of a hydraulic jack. The hydraulic jack includes a valve seat, a valve ball, and a cap. When the jack is not operated, a valve hole is opened; the vent of the cap is communicated with the oil storage tank of the jack so as to maintain the equilibrium of the pressure of the oil storage tank; thereby the piston of the pump can suck oil successfully so that the oil is absorbed into the oil chamber of the pump to be saturated therein. At the moment that the valve ball ejects upwards rapidly, the oil buffer chamber can buffer high pressure draining oil until the oil return operation of the jack is accomplished.

Abstract: A multi-stage telescoping transmission jack with a high flow, lower pressure air-over-oil pump.

Abstract: The invention relates to a new type of hydraulic module for actuating at least one hydraulic control element with a hydraulic pump in a housing, with an electric motor fastened to a first housing side for driving the pump, with a tank located on a second housing side opposite the first side for a hydraulic fluid, e.g. hydraulic oil, with flow channels produced in the housing produced preferably by bore holes for the hydraulic fluid to supply this fluid from the tank to a pump chamber, for transmitting the hydraulic fluid conveyed by the pump to a pressure connection located on the housing, for connection of the at least one actuating element and for returning the hydraulic fluid from the pressure connection into the tank.

Abstract: A ventilation valve of a hydraulic jack is dedicated to be mounted at an outer wall of an oil storage tank of a hydraulic jack. The hydraulic jack includes a valve seat, a valve ball, and a cap. When the jack is not operated, a valve hole is opened; the vent of the cap is communicated with the oil storage tank of the jack so as to maintain the equilibrium of the pressure of the oil storage tank; thereby the piston of the pump can suck oil successfully so that the oil is absorbed into the oil chamber of the pump to be saturated therein. At the moment that the valve ball ejects upwards rapidly, the oil buffer chamber can buffer high pressure draining oil until the oil return operation of the jack is accomplished.

Abstract: The present invention provides a hydraulic actuator suitable for use in marine and other harsh environments. In the presently preferred embodiment, the hydraulic actuator includes a motor that is coupled to a pump assembly that is configured to displace hydraulic fluid. The hydraulic actuator also includes a cylinder bore that has an upper chamber and a lower chamber which are separated by a movable piston member. Pressure actuated valves are used to regulate the flow of high pressure hydraulic fluid to the cylinder bore. The pressure actuated valves are actuated in response to pressure generated by the pump assembly.

Abstract: A hydraulic cylinder in which the cylinder head contains a motor-driven fluid pump, fluid reservoir, and a main control valve for the cylinder. The cylinder includes a transfer tube that extends through the center of the cylinder's piston and terminates within a hollow ported section of a piston rod. The cylinder head can additionally include two electrically-actuated pilot valves and two pilot-operated check valves. The pilot-operated check valves include structure that, in combination with passages in the cylinder head, cause both pilot-operated check valves to open when pressurized fluid is being directed to one of the pilot-operated check valves by the main control valve.

Abstract: A hydraulic cylinder in which the cylinder head contains a motor-driven fluid pump, fluid reservoir, and a main control valve for the cylinder. The cylinder includes a transfer tube that extends through the center of the cylinder's piston and terminates within a hollow ported section of a piston rod. The cylinder head can additionally include two electrically-actuated pilot valves and two pilot-operated check valves. The pilot-operated check valves include structure that, in combination with passages in the cylinder head, cause both pilot-operated check valves to open when pressurized fluid is being directed to one of the pilot-operated check valves by the main control valve.

Abstract: The invention relates to a drive device for a hydraulic elevator, the device comprising an actuator (1) whose pressure chamber (1a) is connected to a pump (11) via a down duct (15) and via an up duct (16). A pressure accumulator (4) is connected to the down and up ducts (15, 16) via parallel ducts (15a, 16a), each duct having an electrically controlled valve (2, 2a; 6, 6a). While the elevator is moving downwards, hydraulic fluid is transferred from the pressure chamber (1a) to the accumulator (4) via the down duct (15) and the parallel duct (16a). While the elevator is moving upwards, hydraulic fluid is transferred from the accumulator (4) to the pressure chamber (1a).

Abstract: A control system is provided with a float condition to permit a double acting hydraulic cylinder to freely extend or retract in response to external forces acting on the hydraulic cylinder. The system includes a pair of pilot operated poppet valves disposed between the opposite sides of the hydraulic cylinder and a directional control valve. The pilot condition is obtained by opening a pair of pilot operated control valves to vent the control chambers of the poppet valves to a tank through a pair of float check valves. The float check valves are operative to prevent higher pressure fluid from being transmitted from the tank to the control chambers of the poppet valves when a negative pressure occurs in the side of the hydraulic cylinder that is connected to the control chamber.

Abstract: In a swash plate type hydraulic unit for use as a swash plate type hydraulic pump and a hydraulic motor, a plurality of block plates 41 to 45 being divided at split planes extending orthogonal to a cylinder block axis X are soldered to one another to form a cylinder block 4. Inlet holes 25i and 39i for supporting plungers 27 and 41 slidably therein are formed in an inlet-side one of the block plates 41, 42; 44, 45 located close to plunger swash plates 9a and 19a, while in remaining inner-side ones of the block plates 43 to 45; 41 to 43 are formed inner holes 25o and 39o of a diameter larger than that of the inlet holes 25i and 39i, the inner holes 25o and 39o each defining an oil chamber to which the outer peripheral surface of the associated plunger 27, 41 faces. With this arrangement, a cylinder block structure superior in mass-productivity is provided.

Abstract: A firewood splitting machine is composed of a support frame, a cutter mounted on one end of the support frame, an oil pressure cylinder mounted on another end of the support frame, and an oil injecting device mounted in the support frame. The oil pressure cylinder consists of a cylindrical body, a piston, a rod member, a subsidiary piston, and a subsidiary rod member. The piston is located in the cylindrical body such that an oil pressure space is formed between the piston and a rear end cover of the cylindrical body. The rod member is fastened at one end thereof with the piston such that another end of the rod member is jutted out of a front end cover of the cylindrical body. A pivoting hole is extended along the direction of the longitudinal axis of the rod member such that the pivoting hole is in communication with the oil pressure space.

Abstract: A hydraulic tile and trim mechanism for a marine outboard drive that provides a compact assembly and which ensures that contaminants which may enter the hydraulic fluid can accumulate in the fluid reservoir and will not be circulated by the fluid pump. This is accomplished by positioning the reservoir below the fluid pump and using a pick-up tube that does not extend into the bottom of the reservoir so that the contaminants can accumulate therein without being circulated.

Abstract: A system for above grade and below grade installation, for rendering the mass weightless in preparation to being lifted subject to its mass inertia, wherein a pre-charge is applied to the pneumatic end of a pressure accumulator at a pre-set pressure, and an adjustment made charging the other end of the accumulator with a working fluid for balancing the mass as required against gravity and with a volume of working fluid to ensure operation, the pre-set gas pressure being increased by the adjustment to apply a working pressure for counterbalancing the mass above and below its weight as required.

Abstract: The forcing rod of a hydraulically operated tool has thereon intermediate its ends an enlarged-diameter piston head which reciprocates in the bore of a cylinder housing, and divides the bore into a pressure chamber and a reservoir chamber. A hand-operated pump mechanism on the housing is operable to draw fluid from the reservoir chamber and to pump it under pressure into the pressure chamber, thereby causing the forcing rod to advance out of one end of the housing against the resistance of a return spring. Each of two plates removably secured to opposite sides of the housing contain to elongate chambers which communicate at one end with the reservoir chamber, and which contain spring-loaded pistons which function to maintain pressure on the fluid in the reservoir chamber.

Abstract: A hydraulic system 10 provides a positive supply of hydraulic fluid at a controlled pressure to plurality of pumps. The system comprises a fluid reservoir 15 having outlet means to supply fluid to an auxiliary pump 30. A pressure chamber 16 communicates with a reservoir 15 and has outlet means to supply fluid to a plurality of working pumps 11, 12, 13. An inlet manifold 18 is provided for receiving fluid returned from the working and auxiliary pumps.

Abstract: An apparatus and a method for reducing seal stiction is provided. In the method, a first step provides a fluid cylinder comprising a piston displacably mounted in a housing containing pressurized fluid is provided in the first step. The housing has first and second seals in register with the piston. In a second step, the second seal is applied to maintain pressure within the housing when the piston is in a static state. In a third step, the first seal is applied to maintain pressure within the housing and the second seal relaxed prior to displacement of the piston. In a fourth step, the second seal is applied to maintain pressure within the housing and the first seal relaxed subsequent to the displacement of the piston. An apparatus is provided for applying one of the first or second seals and relaxing the other of the first or second seals, before and after displacement of the piston.

Abstract: A hydraulic fluid reservoir contains an extensible bladder which has its exterior exposed to the fluid and its interior vented to the exterior of the reservoir. The interior of the bladder is sealed from the hydraulic fluid in the reservoir. Depletion of the fluid from the reservoir results in distension of the bladder and replenishing the fluid to the reservoir collapses the bladder. The bladder is pleated and a tie-rod which holds the reservoir together extends through the bladder.

Abstract: A surgical instrument actuation system is provided with a double-acting fluid pressure piston pump and a double-acting fluid actuator. An operating member is connected to the pump piston, and a two-position directional valve communicates between the pump and actuator. A valve actuator means is responsive to the pump pressure or to the position of the pump piston or actuator piston. This switches the valve from the first position to the second position so that the system operates to apply a higher actuator force at a lower stroking speed.

Abstract: A hydraulic jack movably supported by a plural casters has a vertically extending hydraulic cylinder with telescoping piston rods, has a load supporting frame at an upper end of the innermost piston rod, and has a reservoir partially filled with hydraulic fluid. A single foot pedal is pivotally supported on the jack, and is movable between first and second positions through a center position. A hydraulic valve arrangement is responsive to movement of the actuating member toward its first position for permitting fluid flow from the reservoir to the hydraulic cylinder and is responsive to movement of the actuating member toward its second position for permitting fluid flow from the hydraulic cylinder to the reservoir. A kicker lever supported for pivotal movement about the same axis as the actuating member is operatively coupled to the actuating member for movement therewith by two springs, and can actuate an air valve.

Abstract: An airless hand held hydraulic pump unaffected by gravity continuously maintains pressure on the fluid in a dynamic reservoir chamber to enable pumping into a dynamic pressure chamber for actuating a forcing rod irrespective of the orientation of the pump. A release valve permits fluid return from the pressure chamber into the reservoir chamber. The pump can be fitted with a tool such as a door forcer.

Abstract: Procedure for pumping liquid at high temperature through a pipe, characterized in that the liquid at high temperature is pressed, by means of a fluid at low temperature that is inert in relation to the liquid at high temperature, away out of a first reservoir that is mounted on an extremity of the pipe. The liquid at high temperature which is pressed out is taken up in a second reservoir that is mounted on the other extremity of the pipe, while the aforementioned fluid that is in the second reservoir, is let out, after a time the liquid at high temperature is now pressed out of this second reservoir and is taken up again in the first reservoir, and this by means of the aforementioned fluid that is now let out of the first reservoir and is pumped into the second reservoir. The pumping procedure including means to calculate a flow rate through the pipe via temperature and level indicators, taking into account expansion or contraction of the high temperature liquid.

Abstract: An hydraulic actuator composed of a double-acting actuator, a mobile switching member disposed in a housing connected hydraulically to the actuator, two fluid inlet and outlet pipes and a control member adapted to command the mobile switching member to move between a neutral configuration and an active service configuration. A variable speed pump system is connected to the housing by an auxiliary circuit; the mobile switching member has an active second configuration in which the actuator communicates with the auxiliary circuits, whereby the actuator, the pump system and the auxiliary circuit constitute a hydrostatic transmission.

Abstract: A system for cooling individual integrated actuator packages (IAPs) positioned throughout the aircraft in a power-by-wire actuation system is disclosed. A low-pressure hydraulic fluid circulates throughout the aircraft to control the temperature of the individual IAPs and to maintain and replenish the hydraulic fluid within the individual IAPs. A thermo-control loop containing low-pressure hydraulic fluid includes a pump, low-pressure hydraulic lines, a heat exchanger, a reservoir and a filter. The entire system provides heat transfer for a high- or low-temperature environment, as may be present on an aircraft. The individual IAPs may be coupled together in series or, alternatively, in parallel, depending upon the design constraints of the system. Compared with distributed hydraulic systems, energy consumption, weight, and cost are significantly reduced by using a low hydraulic pressure for the circulating fluid. Survivability is significantly increased over that provided by a distributed hydraulic system.

Abstract: The disclosed mechanism is designed so as to be impervious and give a motion of translation enabling, for example the driving of a hinged arm. The mechanism has a hydraulic circuit with fluid, a jack associated with a pull-back spring and a pump to bring the jack to the working position. The pump is actuated by a motor. The pump and the motor are entirely placed inside a common enclosure so that the motor, with its shaft, bathes in the fluid of the hydraulic circuit. The mechanism is designed for sonars, to unfold and fold their antennas mounted on hinged arms.

Abstract: In a hydrostatic transmission, an oil expansion reservoir is formed as an integral part of the hydrostatic transmission housing, providing an extension to the housing chamber which encloses motion transmitting components of the transmission. The reservoir is defined by a yieldably compressible hollow body mounted within the chamber of the transmission housing. The hollow body is sealably attached at its open end to the outer wall of the transmission housing. The body includes a continuous cylindrical sidewall connected to a closed end wall and formed of alternating reversed annular folds which cause compression and expansion of the body sidewall to occur in a bellows-like fashion rectilinearly along a central longitudinal axis of the body.

Abstract: A solar deep well steam pump has a solar collector, a steam boiler in the collector's focus, a deep well bladder pump having an actuating tube and a water delivery tube, and a mechanism periodically injecting steam under pressure from the boiler into the actuating tube of the bladder pump, the mechanism having an expansion chamber connected to the actuating tube of the bladder pump, a long period pendulum swinging by gravity to a first position, a steam injection valve between the boiler and the expansion chamber, the steam injection valve being opened by the pendulum in the first position, an impulse bladder connected to the expansion chamber so that steam pressure in the expansion chamber inflates the impulse bladder against the pendulum in the first position to urge the pendulum against the force of gravity toward a second position, an exhaust valve leading from the expansion chamber to the atmosphere, the exhaust valve being opened by the pendulum in the second position, the injection of steam into the ex

Abstract: A hydraulic system which includes an auxiliary reservoir having an elastic fluid impervious chamber and apparatus for sealing the elastic fluid impervious chamber with the interior thereof in fluid communication with the inside of an associated fluid reservoir. Apparatus is provided for preventing excessive positive or negative pressure from building in the reservoir. Some embodiments may include a desiccant to dry the air which is within the reservoir above the liquid hydraulic fluid. A moisture indicator may also be used to visually verify that a tight vapor barrier is maintained. The extended surface area of the auxiliary reservoir also acts as a means of rejecting excess heat generated by the operating hydraulic system.

Abstract: The flow matching valve disclosed herein incorporates a fill port in addition to the source, load and respective drain ports employed in previous load matching valves. The inclusion of the fill port allows reconfiguration of hydraulic systems to reduce leakage and improve reliability and to eliminate auxiliary check valves in certain configurations.

Abstract: The hydraulic tool of this invention includes a pressure chamber into which a fluid is pumped. A pump chamber has an inlet port and outlet port at opposite ends thereof and a pump plunger extends into the chamber with an annular space around it. An annular shoulder is provided on either the chamber or the plunger and a seal ring or sleeve fits slidably on the other component to seal against the shoulder. A spring biases the seal ring against the shoulder, and when the pump is extended to force fluid out the outlet port, the pressure in the chamber augments the spring force. Then, when the rod is retracted to create a void, fluid in the reservoir forces the seal ring or sleeve away from the seat surface to enter the inlet port.

Abstract: The invention contemplates a hydraulically operated twin-cable suspension for a clamshell or the like load-handling device. In a preferred embodiment, a charged accumulator is effectively a counterweight and is the source of all hydraulic fluid needed for the full range of actuation of two traction cylinders, one for each of the respective cables. Two power integrators are employed: one is interposed between the accumulator and one of the traction cylinders, and the other is interposed between the accumulator and the other traction cylinder; hydraulic control interconnections between the respective integrator circuits enable load sharing by both cables and simplified single-lever control of plural clamshell functions, including (a) an automated closing dig into loadable material and (b) a quick opening for load discharge.

Abstract: A hydraulic apparatus for converting hydraulic pressure into mechanical movement for operating a tool or other device, operated by a pump block having a bore therein and a moveable plunger disposed within said bore. A cylinder is disposed over the pump block. The cylinder is captively held over the pump block and is moveable with respect thereto along the common axis. A fluid reservoir is defined between the cylinder and the pump block, and contains the hydraulic fluid. The plunger is operated by a pair of moveable arms secured to the apparatus and causes pressure to build in the fluid in an inlet chamber which communicates between the pump block and the cylinder. A pressure control valve is mounted adjacent the pump block and limits the hydraulic pressure which may be applied in the system. A release valve and apparatus is provided for releasing the hydraulic pressure and returning it to the reservoir.

Abstract: A volume control device for a sealed reservoir for storing oil under pressure and which supplies oil to a power circuit. The volume control device has an expansible bellows assembly which contracts upon a predetermined increase of volume of oil in the reservoir to bring a rod into engagement with a ball check valve and unseat the valve for dumping of oil overboard from the reservoir. The dumping of excess oil from the reservoir is controlled by an increase of volume of oil in the reservoir, rather than an increase in oil pressure.

Abstract: A force-delivering tool such as a log splitter wherein a pusher member carried on a cylinder is forced against a blade carried on a frame to which the piston is secured. The cylinder is driven relative to the piston by means of a reciprocating plunger carrying a cup on the end that forces fluid past a one-way valve ahead of the piston. Oil is pressurized by both the bottom of the cup and its annular end but, when resistance is encountered to build up pressure, a relief valve evacuates the annular chamber so that all the force is concentrated in the area at the bottom of the cup. The entire actuating valve may be backed away to relieve pressure as desired or at the completion of a desired stroke.

Abstract: A hydraulic control package or assembly (30) for use in a marine steering system (10) having a steering helm pump (12) with port (14) and starboard (16) fluid outlets and a return inlet (18) for hydraulically actuating a piston (22) in a hydraulic cylinder (20) having port (24) and starboard (26) inlets for moving the piston (22) back and forth in the cylinder (20) in response to fluid delivered from the helm pump (12). A fluid reservoir (32, 34, 36) is closed and pressurized with air and is defined by an open ended tube (32) having a cap (34) sealing the top end of the tube (32) and a valve body (36) sealing the bottom end of the tube (32). The valve body (36) houses the control valve means for controlling the fluid flow in the system between the helm pump (12) and the actuating cylinder (20). The cap (34) and valve body (36) are held against the respective ends of the tube (32) by tie rods (50).

Abstract: A hydropneumatic system, especially for operating landing gear of truck trailers, is operable from a source of pressurized air. The system includes separate first and second hydraulic fluid sources. Dual hydraulic cylinders are operated by the fluid. Each has a piston and an extensible member connected to the piston for providing extension and retraction of the gear legs in response to hydraulic pressure in chambers on opposite sides of the pistons. An air valve provides the pressurized air to one of the fluid sources for enabling it to provide hydraulic fluid. An air-operated hydraulic pressure boosting pump is selectively operable to boost the hydraulic fluid pressure thus provided to much greater than air pressure.