Abstract: A hydraulic actuator; a control valve that controls supply and discharge of hydraulic oil to and from the hydraulic actuator; a pilot operation valve connected to the operation valve by a pair of pilot lines; a proportional solenoid pressure-reducing valve provided on at least one of the pair of pilot lines; an operation detector that outputs an operation amount signal in accordance with an inclination angle of an operating lever of the pilot operation valve; and a controller that controls the proportional solenoid pressure-reducing valve such that, from immediately after a change amount per unit time in the operation amount signal outputted from the operation detector has decreased by a threshold value or more, a pilot port pressure of the control valve gradually decreases to zero due to communication of a secondary pressure port and a tank port of the proportional solenoid pressure-reducing valve with each other.

Abstract: A system for recovering energy from a hydraulic actuator and to a method of operating the system are described. The system may have a hydraulic actuator and a source of hydraulic pressure, comprising a hydraulic pump, in fluid communication with the hydraulic actuator for pressurizing the hydraulic actuator. The system may also have a hydraulic accumulator assembly for selectively absorbing energy from the hydraulic actuator or via the hydraulic actuator. The system may also have a first one-way valve configured to provide fluid communication between the hydraulic actuator and the hydraulic accumulator assembly. The first one-way valve may be configured to permit a flow of fluid through the first one-way valve from the hydraulic actuator to the hydraulic accumulator assembly. The first one-way valve may also be configured to block a flow of fluid through the first one-way valve from the hydraulic accumulator assembly to the hydraulic actuator.

Abstract: This hydraulic system is provided with a hydraulic pump, a control valve, and a pilot pressure supply unit. The pilot pressure supply unit has: an electromagnetic proportional valve that has a detent-type emergency manual operation function with which a pilot oil passage can be opened manually and generates pilot pressure for a control valve; a controller that controls the degree of opening of the electromagnetic proportional valve in accordance with the operation of an operation lever; and a pilot pressure switching unit that switches the oil pressure state of the pilot pressure supply unit between an on-loading state and an unloading state. The pilot pressure switching unit performs control to implement the unloading state when the electromagnetic proportional valve is being opened manually and performs control to implement the on-loading state after the electromagnetic proportional valve has been opened manually.

Abstract: A telescopic actuator comprising a cylinder (2) in which a rod (3) is mounted to slide along a sliding axis (X), the actuator including a locking member comprising a locking finger (10) that is movable along a locking direction (Y) that is perpendicular to the sliding axis, between a locking position in which an end (9) of the locking finger (10) is engaged in a groove (8) of the rod in order to lock the rod in position, and a retracted position in which the end of the finger is disengaged from the groove in order to release the rod, a locking indicator (20) being secured to the locking finger to be movable between a position indicating locking when the locking finger is in the locking position, and a position indicating unlocking when the locking finger is in the retracted position, the actuator being characterized in that the locking indicator is secured to the locking finger by a connection (22, 23, 24) suitable for being interrupted in the event of the end of the finger being broken off while the rod is l

Abstract: A torque converter drive plate, comprising a drive stud that includes a head, and a drive plate that includes a single continuous layer of material extending from a front of the drive plate, around a radial surface of the drive plate, and to a back of the drive plate, wherein the drive stud is secured into a hole of the drive plate, wherein the back of the drive plate covers the head and is in contact with a surface of the head.

Abstract: A piston accommodated in an internal space of a cylinder and forming a pair of pressure chambers together with the cylinder, the piston being configured to move relative to the cylinder; a first actuator connected to one pair of pressure chambers; a second actuator connected to the other of the pair of pressure chambers; a position detector configured to detect a position of the piston relative to the cylinder; a pressure detector configured to detect a pressure of one pair of pressure chambers; and a controller configured to control the first actuator and the second actuator. The controller controls one of the first actuator and the second actuator that the position detected by the position detector is made close to a target position and controls the other of the first actuator and the second actuator that the pressure detected by the pressure detector is made close to a target pressure.

Abstract: A work vehicle includes a hydraulic actuator, a control valve, a pressure sensing unit, a force imparting component, and a controller. The hydraulic actuator varies a steering angle. The control valve controls flow of fluid supplied to the hydraulic actuator. The operation member is configured to be operated by an operator and to control the control valve when varying the steering angle. The pressure sensing unit senses a pressure produced by the hydraulic actuator. The force imparting component imparts an assisting force or a counterforce to operation of the operation member. The controller controls the force imparting component so as to generate resistance to operation of the operation member based on a pressure value sensed by the pressure sensing unit.

Abstract: A crane is disclosed, the crane includes detachable hydraulic cylinder including a head side oil chamber and a rod side oil chamber both to be connected to a control valve through a joint, in which a head side hydraulic detecting section and a rod side hydraulic detecting section are each provided to the hydraulic cylinder, and a connection state between the hydraulic cylinder and the control valve is determined based on a head side hydraulic pressure and a rod side hydraulic pressure in a period until a predetermined time elapses after supply of electric power to the head side hydraulic detecting section and the rod side hydraulic detecting section is started and an operation tool for hydraulic cylinder switches the control valve to a state of supplying hydraulic fluid to the hydraulic cylinder.

Abstract: The invention corresponds to a mechanical hydraulic pumping unit with a radiator integrated to the chassis and a hydraulic circuit which allows it to operate with high flow rates and low pressure or with low flow rates and high pressure. This mechanical hydraulic pumping unit with a radiator integrated is used to supply a particular pressurized oil flow to a hydraulic actuator, which in turn lifts the load exerted by a string of rods and lift the hydrostatic column that is inside an oil well. The main feature of this mechanical hydraulic pumping unit with a radiator integrated is that the radiator is part of the machine's chassis and is located in the middle of two hydraulic oil tanks. The first of these tanks is the oil suction tank, while the second is the oil return tank.

Abstract: A hydraulic hybrid system for rotatory applications has an actuator (49, 91) in the form of a motor pump unit (91). The motor pump unit is coupled to a rotatory-operating device (94) and works as a consumer of hydraulic energy in one operating state of the device (94) and works as a producer of hydraulic energy in another operating state of the device (94). A hydraulic accumulator (1) can be charged by the motor pump unit (91) for energy storage in the one operating state and can be discharged for energy release to the motor pump unit (91) in the other operating state. The hydraulic accumulator is an adjustable hydropneumatic piston accumulator (1) in which a plurality of pressure chambers (19, 21, 23, 25) are delimited by active surfaces (11, 13, 15, 17) of different sizes on the fluid side of the accumulator piston (5).

Abstract: A hydraulic lift apparatus for operating a downhole pump features a hydraulic linear actuator with a piston longitudinally slidable on a central axis of a rotatable portion of a housing. An anti-rotation rod runs longitudinally through the piston at a position radially offset outwardly from the central axis to prevent rotation between the piston and housing. A stationary motor powers a drive train whose output is connected to the rotatable portion of the housing and centered on the central axis. The actuator is one-way actuator with a hydraulically driven upstroke. A leak detection passage extends through the piston to collect fluid that has leaked across the piston seals and convey it to a leak detection port and associated containment tank. A position sensor for monitoring the piston movement features a sensing rod depending downwardly into a hollow piston shaft carried by the piston and connected to the pump rod.

Abstract: A hydraulic system for a machine includes a first pump, an implement pump, a control valve, and an auxiliary circuit. The first pump is configured to supply a first fluid flow to a first circuit, such as a steering circuit. The implement pump is configured to supply a second fluid flow to an implement circuit to actuate a primary implement function. The auxiliary circuit is configured to deliver fluid flow to actuate an auxiliary implement function. The auxiliary circuit is fluidly coupled to the implement circuit. The auxiliary circuit is also coupled to the first circuit by the control valve. The control valve is located downstream, in the direction of fluid flow, of the implement pump and the first pump. The control valve is configured to allow at least a portion of the first fluid flow to enter the auxiliary circuit and be delivered to the auxiliary implement function.

Abstract: The present invention relates to an electronically controlled valve for a variable displacement pump, a hydraulic pump and a hydraulic pump system with switchable control functions. Multiple control functions of different types of hydraulic pumps can be implemented via one single electronically controlled valve combined with control elements and sensors. The hydraulic pump systems can be easily integrated into the overall application systems for intelligent control.

Abstract: The security unit ensures, by blocking the hydraulic flow, that the rod of a cylinder is held in position. It includes two preferably twinned isolation devices, each mounted on one of the hydraulic lines supplying fluid to a chamber of the cylinder. Each isolation device includes two series-connected ball-check valves allowing the flow in the direction of inlet of the fluid into the respective chamber; and a longitudinal, separate rod, inserted between the balls but not linked thereto, and capable of being slidably guided towards each of the balls and driving same. The rod is too short to contact both balls simultaneously when the two valves are closed; but it is sufficiently long to push the ball of the second valve, thereby causing it to open, when it slides under the pushing action of the ball of the first valve upon the latter being controlled to be opened.

Abstract: A fluid-actuated diaphragm drive and a valve arrangement which is equipped therewith, wherein the diaphragm drive has a drive housing with two drive housing parts which are attached to one another axially. An insert body which preferably consists of plastic material and delimits at least one length section of an operating chamber which can be loaded with a fluid is inserted into each of the drive housing parts, wherein a drive diaphragm which is movement-coupled to an output member is clamped in between the two insert bodies. A seal structure which is active between at least one of the insert bodies and the drive housing is capable of preventing an axial flow around the two insert bodies in the region which lies radially between them and the drive housing.

Abstract: A hydraulic cylinder spool valve device, which extends and retracts a cylinder rod of a hydraulic cylinder, includes: a first spool valve having a first dead band and a first opening characteristic; a second spool valve having a second dead band and a second opening characteristic; and a controller performing communication with the hydraulic cylinder by using the first spool valve and positioning the second spool of the second spool valve within the second dead band and performing communication with the hydraulic cylinder by using the second spool valve and positioning the first spool of the first spool valve within the first dead band, and adjusting a characteristic of a switching dead band between the first opening characteristic and the second opening characteristic.

Abstract: In one aspect, a piston assembly for a fluid-driven actuator may include a piston defining a passage extending between first and second chambers of the actuator. The piston assembly may further include a valve having a valve head and a valve stem. The valve may be positioned within the passage and slidable between an open position and a closed position. The valve stem may extend outward from the passage into the second chamber when the valve is positioned in the closed position. Additionally, the piston assembly may include a spring compressed between the valve head and the piston. The spring may be configured to bias the valve to the closed position. The valve may be configured to move to the open position when a pressure in the second chamber exceeds a pressure threshold or when the valve stem contacts a cylinder of the fluid-driven actuator.

Abstract: In order to improve a transmitter unit, especially for a hydraulic brake system, comprising a housing body, a piston which is arranged in the housing body able to move between a starting disposition and a pressure disposition, a pressure chamber bounded by the housing body and the piston, a reservoir for the supply of hydraulic fluid connected by a connection channel to the pressure chamber, a valve unit, which in an open position allows the connection between the reservoir and the pressure chamber and in a closed position breaks this connection, as well as a connection opening for the routing of pressurized hydraulic fluid from the pressure chamber for example to connected hydraulic brake cylinder, so that an escaping of air bubbles from the pressure chamber is more easily possible, it is proposed that in a functional orientation of the transmitter unit, the connection channel opens into a highest end region of the pressure chamber in regard to a direction of gravity.

Abstract: A hydraulic valve assembly for a work vehicle includes a fan and brake function module. A first pump supplies hydraulic pressure to a fan circuit and to first and second service brake circuits of the vehicle. A second pump supplies hydraulic pressure to a steering and work function module that in turn supplies hydraulic pressure to a steering circuit and a work function circuit of the vehicle. The hydraulic valve assembly may also include a work control module and an auxiliary module. The modules of the hydraulic valve assembly are separably connected together via interface surfaces.

Abstract: Disclosed is a paired compress gas energy power system and power method. The paired compress gas energy power system includes: a paired compress gas energy storage device having a high pressure air container and a low pressure air container, the high pressure air container is filled with a high pressure gas, the low pressure air container is filled with a low pressure gas; a paired compress gas energy engine, respectively connected to the low pressure air container and the high pressure air container; and a power device connected to the rotary shaft of the paired compress gas energy engine, the power device is driven by the paired compress gas energy engine. The invention converts the paired compress gas energy into the mechanical torque energy through the paired compress gas energy engine to drive the power device to work, or to drive the generator to generate electric energy.