Abstract: A hydraulic system is arranged to control a plurality of drive motors suitable for driving conveying apparatus such as a conveyor belt. The hydraulic system includes a modular master and slave hydraulic units implemented as hydraulic circuits in which pressure sensors and pressure reducing valves provide speed, torque and directional control.

Abstract: A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

Abstract: A hydraulic system, mining machine and method of controlling a hydraulic actuator. The hydraulic system (HS) is provided with a control valve (23) for controlling movement direction and speed of a hydraulic actuator (HA) connected to the system. Generated force of the hydraulic actuator is controlled independently relative to the control valve by means of counterbalance valves (Cb1, Cb2) and servo valves (Sv1, Sv2) controlling their opening pressure. The counterbalance valves and the servo valves operate as a meter-out control assembly which controls flow of hydraulic fluid discharged from working pressure spaces (16a, 16b) of the hydraulic actuator. The disclosed system may be implemented to control a mining boom (3) of a mining machine (1).

Abstract: A hydraulic system is arranged to control a plurality of drive motors suitable for driving conveying apparatus such as a conveyor belt. The hydraulic system includes a modular master and slave hydraulic units implemented as hydraulic circuits in which pressure sensors and pressure reducing valves provide speed, torque and directional control.

Abstract: A control unit for controlling machine functions of a mining machine, such as an underground mining machine, tunneling machine or bolting rig, includes a flameproof housing having at least one fluid inlet and at least one fluid outlet, and a plurality of fluid control valves respectively communicating with the at least one inlet and outlet. In particular, the fluid control valves are formed inside at least one valve monoblock, the monoblock including a plurality of distinct fluid passages.

Abstract: A hydraulic system arranged to control at least two hydraulic actuators via a metering control valve assembly. The hydraulic system is advantageous to control a pivoting arm of an undercutting mining machine according to at least two modes of operation including an idling mode and a cutting mode. In particular, the hydraulic actuators may be controlled by quantitative variation of fluid flow speed and pressure.

Abstract: A hydraulic system arranged to control at least two hydraulic actuators via a metering control valve assembly. The hydraulic system is advantageous to control a pivoting arm of an undercutting mining machine according to at least two modes of operation including an idling mode and a cutting mode. In particular, the hydraulic actuators may be controlled by quantitative variation of fluid flow speed and pressure.

Abstract: A control unit for controlling machine functions of a mining machine, such as an underground mining machine, tunneling machine or bolting rig, includes a flameproof housing having at least one fluid inlet and at least one fluid outlet, and a plurality of fluid control valves respectively communicating with the at least one inlet and outlet. In particular, the fluid control valves are formed inside at least one valve monoblock, the monoblock including a plurality of distinct fluid passages.