Abstract: The invention relates to a mining electromagnet for the switching of hydraulic pilot valves or main control valves used in underground mining operations, with a coil which can be connected to an intrinsically-safe power unit, with an armature which can be displaced by application of current to the coil and with an electronic control device 20, by means of which the current which is conducted to the coil can be set during the drawing-in phase of the armature to an excitation current, and in its holding phase can be set to a holding current which is lower than the excitation current.

Abstract: The present invention relates to a method for operation of an electro-magnet (2, 3) connected to an intrinsically safe direct current circuit which can be switched under control between two positions for the operation of the closing body of a hydraulic valve (5, 6), whereby using of an electronic control unit, the coil windings of the electro-magnet (2, 3) are taken in the pull-in phase of the armature of the electro-magnet to an exciting current and in the retaining phase of the armature to a lower retaining current as opposed to the excitating current, and a device with which the retaining current reduction is realized.

Abstract: The invention relates to a mining electromagnet for the switching of hydraulic pilot valves or main control valves used in underground mining operations, with a coil which can be connected to an intrinsically-safe power unit, with an armature which can be displaced by application of current to the coil and with an electronic control device 20, by means of which the current which is conducted to the coil can be set during the drawing-in phase of the armature to an excitation current, and in its holding phase can be set to a holding current which is lower than the excitation current.

Abstract: A solenoid operated hydraulic valve for electro-hydraulic controlled underground mining installations such as advancing support frame controllers, with an actuator housing holding coil bodies, an armature, a magnetizable core, and an operating pin of at least two solenoids. The head end for the operating pins of each solenoid has a cut-out for an operating stroke adjuster. A head plate removable from the actuator housing is provided with a manual operating device for each operating pin and is fastened to the head end of the actuator housing with a head seal between them, a removable valve block accepting the hydraulic multi-way valves and an interposed base seal fastened to the actuator housing base. A housing having a socket connects to an intrinsically safe current supply and accepts the operating electronics for the solenoids, and is located on the side of the actuator housing. In each head end cut-out, an electronic protective circuit for the associated coil body is arranged.

Abstract: The present invention relates to a method for operation of an electro-magnet (2, 3) connected to an intrinsically safe direct current circuit which can be switched under control between two positions for the operation of the closing body of a hydraulic valve (5, 6), whereby using of an electronic control unit, the coil windings of the electro-magnet (2, 3) are taken in the pull-in phase of the armature of the electro-magnet to an exciting current and in the retaining phase of the armature to a lower retaining current as opposed to the excitating current, and a device with which the retaining current reduction is realised. In accordance with the present invention it is proposed that the actual current in the coil winding following the actuation of the electro-magnet (2, 3) is continuously measured and evaluated to detect the movement of the armature.

Abstract: A solenoid operated hydraulic valve for electro-hydraulic controlled underground mining installations such as advancing support frame controllers, with an actuator housing holding coil bodies, an armature, a magnetizable core, and an operating pin of at least two solenoids. The head end for the operating pins of each solenoid has a cut-out for an operating stroke adjuster. A head plate removable from the actuator housing is provided with a manual operating device for each operating pin and is fastened to the head end of the actuator housing with a head seal between them, a removable valve block accepting the hydraulic multi-way valves and an interposed base seal fastened to the actuator housing base. A housing having a socket connects to an intrinsically safe current supply and accepts the operating electronics for the solenoids, and is located on the side of the actuator housing. In each head end cut-out, an electronic protective circuit for the associated coil body is arranged.

Abstract: An electro-hydraulic control valve for an hydraulic self advancing support, comprising a 3/2-way valve (11) which can be connected to a high pressure line and a direct current magnet (12) for the control of the control valve, a permanent magnet (22) provided to hold a switching pin (20) in its switched position, and an electronic controller for reversing the polarity of the direct current magnet (12) to control the reversal of the directional control valve (11).