Abstract: The invention relates to a drive (1) having an energy recovery function. The drive having an energy recovery function comprises a hydrostatic piston machine (9) and at least one storage element (13) which is connected to said hydrostatic piston machine. Said hydrostatic piston machine (9) and the at least one storage element (13) are connected together by means of a storage line. Said storage line is divided into a first storage line section (11) and into a second storage line section (12) by a throttle value unit (15). Said throttle valve unit (15) comprises a control pressure valve unit (16) and a built-in valve (17). The control pressure valve unit (16) produces a control pressure which acts upon the built-in valve (17).

Abstract: The invention relates to a drive (1) having an energy recovery function. The drive having an energy recovery function comprises a hydrostatic piston machine (9) and at least one storage element (13) which is connected to said hydrostatic piston machine. Said hydrostatic piston machine (9) and the at least one storage element (13) are connected together by means of a storage line. Said storage line is divided into a rust storage line section (11) and into a second storage line section (12) by a throttle value unit (15). Said throttle valve unit (15) comprises a control pressure valve unit (16) and a built-in valve (17). The control pressure valve unit (16) produces a control pressure which acts upon the built-in valve (17).

Abstract: A hydraulic control arrangement for a mobile working machine has at least one hydraulic cylinder with the aid of which a working tool is moved, a directional control valve for controlling pressure-fluid channels between chambers of the hydraulic cylinder, a pressure-fluid source and a tank, a hydraulic accumulator connected to the pressure-fluid source via a filling line, and a control valve to open and to close a connection between the hydraulic accumulator and a pressure chamber of the hydraulic cylinder. To achieve a damping of pitching movement of the machine, a pilot-operated shutoff valve is connected upstream of the pressure chamber of the hydraulic cylinder, and opens when the directional control valve is actuated to allow pressure fluid to flow off from the pressure chamber to the tank.

Abstract: A hydraulic control arrangement for a mobile working machine which serves for damping pitching vibrations and has a hydraulic accumulator which can be connected to a hydraulic fluid source via a filling valve and which can be connected to a pressure chamber of a hydraulic cylinder, and a shut off valve which, with a first condition fulfilled, can be moved into a through position in which hydraulic fluid can flow through it in the direction from the hydraulic accumulator to the pressure chamber of the hydraulic cylinder and vice versa. The shut off valve may, at the same time, also be the filling valve. A first condition may be that a certain traveling speed is exceeded. Limiting the accumulator pressure to a limit pressure is intended to keep the wear on the hydraulic accumulator low and to increase the safety.

Abstract: An hydraulic control arrangement which is chiefly used for a mobile working machine, especially for a wheel loader, and has at least one hydraulic cylinder with the aid of which a working tool can be moved, a directional control valve for controlling the pressure-fluid channels between the hydraulic cylinder, a pressure-fluid source and a tank, a hydraulic accumulator which can be connected to the pressure-fluid source via a filling line, and a control valve with the aid of which a connection between the hydraulic accumulator and the hydraulic cylinder can be controlled to open and close. The aim of such a hydraulic control arrangement is to avoid undesired movements of the hydraulic cylinder. This is achieved wherein the fact that the hydraulic accumulator can be filled up only when the directional control valve is actuated.

Abstract: A 2-way fitted valve (2) includes a main piston (6) guided in a valve bush (4) and allowing flow of a hydraulic fluid therethrough, whereby an inlet port (B) is connected with an outlet port (A). In the region of a throttle point (8) of the main piston (6) an effective surface (D-d) is provided, so that due to the pressure drop at the throttle point (8) a pressure force acts on the main piston (6) such as to urge it in the direction towards its home position.

Abstract: A two-way insert valve having an insert assembly which can be installed in a receiving bore hole and having a valve cover for closing the receiving bore hole, the insert assembly consisting of two parts, has a bush with several radial passages and with an axial passage and a ring arranged between the bush and the valve cover and has a valve piston by which a connection between the radial passages and the axial passage can be controlled and which is displaceable in opening direction up to a stop. A closing spring urges the valve piston in closed direction. The valve piston in its closed position is guided by the bush at least approximately up to the first end of the bush facing the ring.

Abstract: A hydraulic control for a dividing machine tool, in particular a shear or cutting press, in which a damping device is provided in order to counteract a sudden downward movement of the working piston upon the cutting through of a workpiece during an operating stroke.

Abstract: A hydraulic control circuit for building machinery includes a hydraulic cylinder to operate a tool. To stabilize vibrations of the tool around the pitch axis, a hydraulic accumulator is provided to be connected to a pressure source via a fill line. A shut-off valve is disposed in the fill line, which valve is subjected to the pressure in the accumulator such that in operating the cylinder the accumulator is loaded to a pressure corresponding to the load pressure. The system is very simple in structure and fluid losses are eliminated.

Abstract: A pilot controlled sequence valve having a pilot valve and a main valve is provided. This sequence valve is preferably used for switching on and switching off a charging operation of a hydraulic accumulator. The displacement volume of the main spool of the main valve is directed via an orifice to the tank when the switching into the pressureless circulation occurs.

Abstract: For the relief of a highly pressurized hydraulic liquid in a working chamber of pilot controlled 2/2 poppet valve is used. The working chamber is further connected to a pressure relief valve, the output of which is connected to a control conduit extending between a control chamber of the 2/2 poppet valve and the pilot valve. The apparatus of the invention requires a shorter period of time for the pressure relief without the danger of relief noise.

Abstract: To reduce the noise on response of a pressure-limiting valve, downstream of the valve seat an annular space, an annular gap and a further annular space are provided. This flow-off system gives a reduction of the noise level. Moreover, in pressureless circulation the flow resistance of the valve is low because the annular gap is freed by the piston.

Abstract: A hydraulically operated two-way seat type valve includes a housing a forming valve seat, and a locking body displaceable in the housing and cooperating with the valve seat. A cover is mounted on the housing. An actuating piston for actuating the locking body of the valve is guided in the cover. The piston has two opposing piston-shaped extensions one of which is secured to the locking body whereby a non self-closing valve can be switching into the self-closing valve.

Abstract: In a balanced pressure valve with a switching valve for switching over to pressureless circulation, restrictors are provided in the line carrying the system pressure in such a way that the opening motion of the main piston of the balanced pressure valve is heavily damped, and the throttle losses in the bypass line leading from the line carrying the system pressure via the switching valve to the tank are very low when the main piston is open, and with this also the resistance of the main flow via the main piston is correspondingly low.