Abstract: A double action hydraulic jack has a primary hydraulic pump in fluidic communication with the hydraulic fluid reservoir and with the lift cylinder. The hydraulic jack has an auxiliary hydraulic pump also in fluidic communication with the hydraulic fluid reservoir and the lift cylinder. The auxiliary hydraulic pump operates at light-load conditions to drive the jack ram upwards at a rate at least three times faster than at heavy lift-load conditions with only the primary hydraulic pump in operation.

Abstract: Pump assembly for the lift cylinder of a hand fork-lift truck includes a piston pump activated by a bar of a hand fork-lift truck and has a piston chamber and an annulus collector. A three stage control valve connects the lift cylinder with a tank in the lowered setting and connects the piston chamber with the tank in a neutral setting and in a pump setting, connects the piston chamber with the lift cylinder through a first check-valve, with the tank through a second check-valve, a third check-valve between the piston chamber and the annulus collector open to the piston chamber, and a reversing valve between the piston chamber and the annulus collector.

Abstract: A chair elevating/lowering hydraulic device includes at least a foot pump 3 which absorbs oil by an ascent of an operation lever 1, which discharges oil stored by a stepping-on of the operation lever, and which discharges stored oil by a stepping-on of the operation lever to a lowest position, a check valve 5 which is opened by the oil pressure of the oil discharged from the foot pump, which is opened when the foot pump is lowered to the lowest position, and which allows the oil from the non-return side to pass to allow it to return to an oil tank through the foot pump, an elevating/lowering cylinder 7, and an accumulator 6.

Abstract: An oil hydraulic cylinder configured to allow an object to be smoothly and continuously lifted without being clatteringly swayed and unnecessarily rotated by the oil hydraulic while supply of the oil hydraulic remains uninterrupted when an adjusting lever is manipulated for lifting and lowering operations, the cylinder comprising: a cap part protrusively formed thereon with a compression unit for forcibly generating oil pressure, an operation unit fixedly connected to an object for lifting, stopping and lowering the object and an adjusting unit for controlling the lifting, stopping and lowering of the object; a body part connected inside a body case to the compression unit, the operation unit and the adjusting unit and formed with a plurality of cylinders and pistons for carrying out an oil pressing operation; a base part coupled underneath the body part and formed therein with a predetermined flow route; an oil control part for controlling oil flowing in an oil route formed inside the base part; and a manipu

Abstract: A speed regulation jack comprises at least one input cylinder and one output cylinder, and parallel hydraulic lines between the input and output cylinders. A differential oil circuit is connected between the inlet cavity and the return cavity of the output cylinder, and a control valve is connected in series between the return cavity of the output cylinder and the oil tank, and this control valve controls the return oil of the return cavity. This speed regulation jack takes the magnitude of the load as its signal and transfers automatically between different lifting speeds, thus enhancing the lifting efficiency of the jack.

Abstract: A hydraulic jack includes a moveable base seat. A lift arm, a handle and a hydraulic driver each mounted on the base seat. The hydraulic driver is driven by the handle to push the lift arm to lift an object. The hydraulic jack has a compound piston assembly and a hydraulic driver with fluid paths by which the jack can adjust the lift capacity so as to lift quickly and lower slowly.

Abstract: An oil circuit of a jack for rising an object to a preset position rapidly, wherein the oil inlet circuit of a hydraulic loop system is improved. An oil channel is installed between the inner oil chamber of the piston rod and the sequential valve. A check valve is installed between the oil channel and the sequential valve. An oil channel is installed between the sequential valve and the check valve for being connected to the inner oil chamber of the piston rod. By changing the positions of the check valve and the oil channel. When in the working conditions of dump load or light load, the sequential valve is closed, thus, the hydraulic oil may enter into the inner oil chamber of the piston rod from the pumping oil chamber through the check valve so that the piston rod will rise rapidly to a still condition. In the still condition, since the check valve closes the oil channel, the sequential valve will open automatically so that the inner oil chamber of the piston rod is communicated to the inner oil reservoir.

Abstract: A control unit for hand-operated hydraulic jack comprises a control handle (1), a small hand-operated pump (2), a lifting cylinder (4), an inlet pipe and an outlet pipe, wherein the inlet pipe of said lifting cylinder (4) is connected with the small hand-operated pump (2) having a back-moving spring through a lifting oil circuit having a non-return valve (3), which the small hand-operated pump (2) is controlled by the control handle (1); said lifting oil circuit with a non-return valve (3) has an underload-accelerating oil circuit for quickly lifting the load when underloaded; and a release valve is provided on the outlet pipe of said lifting cylinder (4). This unit has the function of quickly lifting the load when underloaded, as well as increasing the force for lifting load when have loaded, and it can be operated simply and reliably.

Abstract: A hydraulic circuit system for one-touch jack and its structure has an inlet circuit, a return circuit and an overload protection circuit with a hydraulic cylinder, a piston rod, a sequence valve, a safety valve and a relief valve, in which the inlet circuit extends from an outer reservoir of a hydraulic cylinder via a check valve to connect to an oil chamber of a manual pump. The oil chamber of the pump is connected to an oil guide tube via another check valve, the oil guide tube is inserted into an inner oil chamber formed in a piston rod to form a closed circuit. The oil chamber of the pump is connected to an inner chamber of the hydraulic cylinder via a sequence valve and the inner chamber is connected to the outer reservoir via a check valve.

Abstract: A hydraulic circuit system for one-touch jack and its structure has an inlet circuit, a return circuit and an overload protection circuit with a hydraulic cylinder, a piston rod, a sequence valve, a safety valve and a relief valve, in which the inlet circuit extends from an outer reservoir of a hydraulic cylinder via a check valve to connect to an oil chamber of a manual pump. The oil chamber of the pump is connected to an oil guide tube via another check valve, the oil guide tube is inserted into an inner oil chamber formed in a piston rod to form a closed circuit. The oil chamber of the pump is connected to an inner chamber of the hydraulic cylinder via a sequence valve and the inner chamber is connected to the outer reservoir via a check valve. When the maximum effect capacity of the oil chamber of the piston rod, a single touch of the pump can raise the hydraulic jack to the required loading position for raising at no load or light load conditions.

Abstract: There is here disclosed a multi-functional cylindrically shaped jack handle with a solid first end characterized by the presence of a centrally located notched out slot for receipt of flat release screws on hydraulic jacks, a first shoulder in proximity to the solid first end to prevent insertion of the handle too deeply into the inner compartment of a jack when pumping it up, a hollowed out second end characterized by the presence of two notches located directly across from one another in the perimeter of the hollowed out second end for receipt of ear screws on or within jacks and a second shoulder in close proximity to the hollowed out second end to prevent inadvertent insertion of this end into the well of a jack when pumping it up.

Abstract: The improved hydrodynamic variator of velocity comprises a pump (3) having radial pistons and a hydromotor (4) also having radial pistons. At least the pump is arranged with a variable eccentricity and there is provided a central body (56) the latter having frontal distributors (30 and 31) which are placed in communication with the radial cylindrical cavities respectively of the pump and the hydromotor by means of the openings of the conduits (32 and 33). By varying the eccentricity of the pump, the rate of flow of the liquid in the pump is varied, thus causing a variation in the number of turns of the hydromotor.

Abstract: A valve for use in a hydraulic compression tool. The valve has a frame with a central chamber, a first inlet, a second inlet and a discharged outlet. A first gate is located at the first inlet. A plunger assembly having a first plunger member and a second plunger member are movably mounted in the central chamber with a spring biasing the plunger member against the second plunger member. The second plunger member has a conduit between the second inlet and the first plunger member. The valve has a first home position that substantially prevents fluid from flowing therethrough. The valve has a second manual release position wherein fluid can flow into the first inlet and out the discharge outlet. The valve also has a third automatic relief position such that in the event a predetermined maximum fluid pressure is exceeded a gate will open between the first plunger and the second plunger member to allow fluid to flow from the second inlet through the valve and out the discharge outlet.

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 pallet truck hydraulic jack has a base plate mounting a lift cylinder with a reciprocal piston or lift rod and a pump cylinder with a reciprocal pump piston. A cartridge type directional control valve assembly within the base plate controls the flow of pressurized hydraulic fluid in respective manifold passages so that manual actuation of the pump effects a quick lift of the frame when it is unloaded, effects an additional application of lifting force through the lift cylinder when the frame is loaded, bypasses pressurized hydraulic fluid to the reservoir when the frame is overloaded, and provides a release of pressurized hydraulic fluid from the pump cylinder and the lift plunger and returns it to the reservoir for lowering the frame and forks.

Abstract: The present invention relates to a hoisting gear for patient-lifting device whereby a plunger device (6) is displaceably mounted in a hydraulic cylinder (4), is supporting patient-carrier means (3) such as a seat or a patient-carrying plate and is raisable my means of a pump device (8) provided to move hydraulic oil between two hydraulic-cylinder chambers (9a, 9b) separated by the plunger device, and whereby a lowering device (39) is provided to permit lowering of the plunger device by producing a counter flow of hydraulic oil between the hydraulic-cylinder chambers.

Abstract: A hydraulic amplifier having a hydraulic motor adapted to drive a high pressure pump for boosting the pressure of low pressure fluid and for supplying high pressure fluid to a hydraulic actuator. The motor also drives a scavenging pump for overcoming high back pressure in the return side of the system. The amplifier is controlled by two valves which may be actuated by manually operating a single lever.

Abstract: A manually operable hydraulic actuator which utilizes a main pump and an auxiliary pump to quickly develop a relatively large useful hydraulic force, for example, in applying compression accessories to stranded conductors such as cables. The main pump develops a relatively high pressure from a low volume of hydraulic fluid to develop the primary hydraulic force. The auxiliary pump develops a relatively low pressure from a high volume of hydraulic fluid to produce rapid advancement of a force-applying piston relative to a work piece. Both the main and auxiliary pumps are operated by the opposed swinging movement of two manually operable handles. One of the handles is selectively movable between a first position for simultaneously actuating both the main and auxiliary pumps and a second position for actuating the main pump only. A pressure relief system is provided to ensure development of the maximum rated pressure of the force-applying piston before retraction thereof can be effected.

Abstract: An improvement in patient lifting devices comprising an upright member, a boom pivotably mounted on the upright member, a fluid cylinder pivotably mounted between the upright member and the boom, and a manually operated pump for the fluid cylinder. The improvement comprises means actuated by the pump handle for transferring fluid from the fluid cylinder to a fluid reservoir, thereby permitting the boom to lower under the combined weight of the boom itself and anyone being carried by the boom.

Abstract: An hydraulic pump comprising a plunger slidingly located within a housing. A first valve is adapted to allow fluid to be drawn from a reservoir into the housing during movement of the plunger in one direction, and a second valve is adapted to allow fluid to flow from the housing during the greater part of movement of the plunger in its other direction. A control apparatus is provided to control the second valve at or near the completion of the plunger's movement in the mentioned other direction to allow fluid to move back through the second valve and into the reservoir.

Abstract: Presented is a hydraulic jack structure having a pump assembly in connection with which is rotatably mounted a pump handle assembly which may be rotated in a horizontal plane through about 320.degree. to permit selective positioning of the handle during a pumping operation.

Abstract: The present invention relates to a hydraulic jack with a base plate on which are attached a pump cylinder, a jack cylinder, and a reservoir concentrically surrounding the jack cylinder, the reservoir being connected to the pump cylinder by means of a first passage, passing through the base plate, and a first nonreturn valve which enables hydraulic medium to flow from the reservoir on pumping, the pump cylinder being connected to the jack cylinder by means of a second passage, passing through the base plate, and a second nonreturn valve which enables hydraulic medium to flow from the pump cylinder on pumping, and the jack cylinder being connected to the reservoir by means of a relief passage and a blocking member including an adjustable bolt.