In a self-propelled construction machine (1), in particular road milling machine, comprising a machine frame (8), at least three travelling devices (12, 16), wherein at least one of the three travelling devices (12, 16) is realized as a pivotable travelling device (16) so that said travelling device (16) is pivotable about at least one vertical pivoting axis in relation to the machine frame (8) between a first pivoted-in and at least one second pivoted-out position, at least one working device (20), in particular a milling drum, for working the ground pavement (3), at least one hydraulic drive system (70) for driving at least two travelling devices (12, 16), wherein at least one of the at least two driven travelling devices is the pivotable travelling device (16), wherein the hydraulic drive system (70) comprises at least one hydraulic pump (78), it is provided for the following features to be achieved: the hydraulic drive system (70) comprises one each hydraulic variable displacement motor (72) for driving the driven travelling devices (12) with the exception of the at least one pivotable travelling device (16), wherein the hydraulic drive system (70) comprises a hydraulic fixed displacement motor (74) for driving the at least one pivotable travelling device (16).

An aircraft with a fuselage and with wings connected thereto, wherein a support strut extends between the fuselage and each of the wings, which support strut is connected both to the fuselage and to the wing. The support strut has a hydraulic working cylinder, which can be pressurized with hydraulic fluid in a controlled manner for the purpose of pivoting the wing.

The agricultural raking machine comprises a frame configured to be towed by a towing vehicle, at least a raking group assembled on the frame and provided with rotating comb-like elements apt to move material mowed onto the ground to form a windrow, and flotation means associated to the raking group and to the frame, the configuration being so that, at variations in height from the ground, the raking group raises/lowers with respect to said frame.

A construction machine incorporates a hydraulic closed circuit system capable of suppressing, even where a selector valve is stuck in an open state by a failure of the selector valve or a control system therefor, unintended operation of a hydraulic actuator and continuing operation of a machine body. The construction machine includes first sensors that detect open-closed states of a plurality of switching valves, first compulsory valve closing devices that change over the plurality of switching valves to a closed position irrespective of open-close control by a machine body controller, and a valve device controller that controls, when it is detected based on the open-closed states of the plurality of selector values detected by the first sensors that one of the plurality of selector values is stuck in an open state, the first compulsory valve closing device such that other selector valve connected to one of the plurality of closed circuit pumps to which the one selector valve is connected is closed.

The invention relates to a hydraulic arrangement (24). The hydraulic arrangement (24) has multiple hydraulic units (20a, 20b), the control units (26a, 26b) of which are connected, in particular in series, via a data connection (28). The control units (26a, 26b) are preferably designed to control selectively only hydraulic cylinders (16a-16d) directly associated with said units, or also indirectly control, via the data connection (28) and the control unit (26a, 26b) of an additional hydraulic unit (20a, 20b), the hydraulic cylinders (16a-16d) associated with said additional hydraulic unit (20a, 20b). The invention also relates to a climbing formwork (22) having at least one climbing unit (10), in particular multiple climbing units (10). The hydraulic units (20a, 20b) can be linked via the data connection (28) such that synchronous lifting and/or lowering of all climbing units (10) can be or is achieved. The hydraulic units (20a, 20b) are preferably connected in a master-slave arrangement or are preferably controlled in a master-slave mode. Also preferably, the hydraulic units (20a, 20b) are designed to switch from the master-slave mode to the stand-alone mode.

A hydraulic drive device for an industrial vehicle includes a variable displacement pump, a displacement control valve, a power steering cylinder, a power steering valve, a loading cylinder, a loading valve, a hydraulic oil passage, and a pilot line. The displacement control valve controls the variable displacement pump to increase displacement of the variable displacement pump when differential pressure between discharge pressure of hydraulic oil discharged from the variable displacement pump and pilot pressure generated in the pilot line is smaller than a predetermined set pressure. A spool of the loading valve is provided with a groove portion that forms a communication passage that makes communication between the hydraulic oil passage and the pilot line at a neutral position of the loading valve when the power steering valve is located in a neutral position.

Device for recovering hydraulic energy in a machine comprising at least a first differential cylinder-piston assembly having a differential cylinder with a separate rod and base side, at least a second differential cylinder-piston assembly having a differential cylinder with a separate rod and base side, and at least one hydraulic accumulator that can be hydraulically connected to at least one of the differential cylinder-piston assemblies, wherein the differential cylinder-piston assemblies are mechanically coupled to one another, and wherein the potential energy of at least one of the differential cylinder-piston assemblies retracting under a compressive load can at least partially be stored in the hydraulic accumulator.

A hydraulic fluid system is disclosed herein. The hydraulic fluid system includes a hydraulic motor including an output shaft, a reduction gear box having a first side and an opposing second side, the reduction gear box being coupled to the output shaft at the first side and coupled to a reduction shaft at the second side, and a magneto-rheological fluid brake (MRF) brake coupled to the reduction shaft.

Different exemplary control systems for a hydraulically powered load-handling clamp, of the type usually mountable on industrial lift trucks or automatically guided vehicles, are disclosed. The disclosed systems variably limit a hydraulic force, by which load-clamping arms move a load substantially transversely, automatically depending on the weight of the load being moved, so as to avoid excessive transverse force applied to fragile loads.

A construction machine incorporates a hydraulic closed circuit system capable of suppressing, even where a selector valve is stuck in an open state by a failure of the selector valve or a control system therefor, unintended operation of a hydraulic actuator and continuing operation of a machine body. The construction machine includes first sensors that detect open-closed states of a plurality of switching valves, first compulsory valve closing devices that change over the plurality of switching valves to a closed position irrespective of open-close control by a machine body controller, and a valve device controller that controls, when it is detected based on the open-closed states of the plurality of selector values detected by the first sensors that one of the plurality of selector values is stuck in an open state, the first compulsory valve closing device such that other selector valve connected to one of the plurality of closed circuit pumps to which the one selector valve is connected is closed.