The invention relates to a hydraulic valve device (1) including a high pressure connection (P) and a low pressure connection (T); at least one motor port connection (A) that is connectable to a motor port (A) on a hydraulic motor (M), preferably a hydraulic cylinder; a flow control valve (F), which is arranged between the high pressure connection (P) and the motor port connection (A) and which includes a flow opening (18) that is adjustable between a fully closed position and a fully open position; and a pressure regulator (R) that is arranged between the high pressure connection (P) and the flow regulating valve (F), wherein a regulator pressure (PR) that acts at a first connection point (3) between the pressure regulator (R) and the flow regulating valve (F) acts on the pressure regulator (R) via a first control conduit (4) to close the same. A second control conduit (5) including a first restrictor (6), is arranged to convey a load pressure (PL) that acts at the motor port connection (A) from a second connection point (7) positioned between the flow regulating valve (F) and the motor port connection (A) via the first restrictor (6) to a third connection point (8) at which a first control pressure (Pc) acts and which third connection point (8) is connected to the pressure regulator (R) to act on the same in the opening direction by means of said first control pressure (Pc), wherein the third connection point (8) is connected to the low pressure connection (T), via an adjustable second restrictor (9).

A hydraulic load-sensing control arrangement for a first and second hydraulic consumer has a variable displacement pump having load-sensing regulation, to which the highest respective load-sensing pressure of consumers is reported. The first consumer has the highest load pressure in normal operation and therefore the highest load-sensing pressure dependent on the load pressure. A pressure reducing valve is arranged in the pressure medium flow path between the variable displacement pump and the first consumer. A spring force from a regulating spring and a regulating pressure dependent on the load pressure of the first consumer are applied in the opening direction of a valve gate in this pressure reducing valve and pressure is applied directly downstream from the pressure reducing valve in the closing direction thereof. A pressure equivalent of the spring force of the regulating spring and the regulating pressure are greater than a pressure of the variable displacement pump.

A load-controlled hydraulic supply for an attachment attached to an agricultural tractor includes a hydraulic high-pressure source providing a volume flow in a supply line, a pressure-compensated control valve including an actuation device for adjusting the volume flow in the supply line, a return line leading to a hydraulic reservoir, and a load-indicating line. The volume flow is adjusted based on pressure feedback prevailing at the load-indicating line.

In a hydraulic driving system for construction machines, when track motors 3f and 3g are operated and the delivery pressure of a main pump 2 increases to a second value PS2 of the set pressure of a main relief valve 14, the set pressure of a signal pressure relief valve 16 increases from a third value PA1 to a fourth value PA2, which is smaller than the second value PS2 of the set pressure of the main relief valve 14, the difference between the second value PS2 and the fourth value PA2 being smaller than the target LS differential pressure. With such a structure, even if one of actuators reaches the stroke end and the delivery pressure of the hydraulic pump rises to the set pressure of the main relief valve, the other actuators do not stop, and further when the main relief valve is configured to increase the set pressure during operation of a specific actuator, the load pressure of the specific actuator does not increase to the increased set pressure of the main relief valve.

A hydraulic system for controlling one or more movable members on construction equipment such as a demolition robot, where the hydraulic system is configurable in a safe mode of operation in which at least one of the movable members is intended to be stationary. The system comprises a load sensing (LS) circuit and a first hydraulic pressure sensor arranged to sense a first LS pressure in a first LS circuit part of the LS circuit. The system also comprises a control unit arranged to monitor the sensed first LS pressure, compare the first LS pressure to a predetermined acceptance criterion associated with stationarity of the one or more movable members, and trigger a safety-related action by the hydraulic system in case the first LS pressure does not satisfy the acceptance criterion even though the safe mode of operation is configured.