Abstract: An advancing assembly for underground powered shield support having at least one floor skid for supporting the powered shield support, an advancing beam and a substantially perpendicularly arranged lift cylinder for lifting the floor skid relative to the advancing beam during an advancing movement. The lift cylinder has a cylinder foot supported above the advancing beam and a cylinder head buttressed on a bridge and hydraulically displaceable relative to the cylinder foot. In order to improve a powered shield support and in particular the advancing assembly of a powered shield support, the lift cylinder is a double lift cylinder having a first cylinder stage, comprising the cylinder head, and a second cylinder stage, wherein a compression spring is arranged between the cylinder stages.

Abstract: A water system for the admission of pressurized water to spray systems arranged on a powered support assembly for underground mining, having at least one spray system for plow or shearer track spraying and having at least one further spray system for goaf space spraying, canopy spraying and side spraying. A central water line feeds spray nozzles of the spray systems. To increase the operating reliability of the water system and thus of the powered support assembly, the control valves for the spray systems are accommodated in a spray valve block which is provided with a connection for the water line and which can be arranged on the powered support assembly as a unit separated from a hydraulic valve block.

Abstract: A water system for the admission of pressurized water to spray systems arranged on a powered support assembly for underground mining, having at least one spray system for plow or shearer track spraying and having at least one further spray system for goaf space spraying, canopy spraying and side spraying. A central water line feeds spray nozzles of the spray systems. To increase the operating reliability of the water system and thus of the powered support assembly, the control valves for the spray systems are accommodated in a spray valve block which is provided with a connection for the water line and can be arranged on the powered support assembly as a unit separated from a hydraulic valve block.

Abstract: A hydraulic shield support is disclosed with at least two adjustable-length hydraulic props supporting a dedicated shield, which are connected through a control bank to a hydraulic fluid supply and borne on base shoes, and to which a pressure in excess of the pressure of the hydraulic fluid may be applied in the set condition of the shield support. In order to provide almost any pressure level at each shield support at a deep face in a simple way, the shield support has at least one pressure intensifier located in a hydraulic pipe system between the hydraulic fluid supply and the hydraulic props, with an oscillating intensifier piston in the form a differential piston effecting the increase in pressure. The low pressure inlet of the pressure intensifier is connected to the setting pressure pipes upstream, and its high-pressure outlet downstream, of a hydraulically-releasable non-return valve.

Abstract: A supply line for connecting a hydraulic advancing support to a hydraulic supply system led along a conveyor is disclosed. The supply line includes a feed connection connectable to the supply system and an advancing support connection located a predetermined distance from the feed connection. A piston arrangement is located within a cylinder tube, and an inner duct having a variable length connects the feed connection and the advancing support connection.

Abstract: An electro-hydraulic assembly for use in underground mining is disclosed. The assembly includes a hydraulic component, such as a valve block for an underground self-advancing roof support, as well as actuators and/or sensors which have a housing and can be connected or are connected via a data-transmission system to a control unit. A function (e.g. withdrawing the support, setting, advancing, or the like) can be activated at the hydraulic component by each actuator, and/or a hydraulic state associated with a measuring point of the hydraulic component or another measured variable associated with the self-advancing roof support can be measured by each sensor. A reader unit is associated with each actuator and/or sensor in its respective housing, and an information element or transponder is associated with the hydraulic component for each function, each control valve, or each measuring point.

Abstract: A lift cylinder arrangement is disclosed for a hydraulic support frame for underground mining. The support frame has a lift cylinder for lifting the base shoes during advancing, which is supported on the one hand on a return rod and on the other hand, in a pivoting manner, with an end supporting head to a drawbar connected to the base shoes. In order to allow a simple, rapid and reliable connection between the supporting head and the drawbar, the supporting head is connected to the drawbar by a plug-type locking system comprising two plug-type locking elements, which include first locking notches on the drawbar, and arranged complementarily thereto second locking notches on the supporting head, whereby the plug-type locking elements engage in at least one of the locking notches with clearance.

Abstract: An electrohydraulic control device for use in the hydraulic systems of advancing support frames of underground mining equipment, which can be switched by means of switching plungers of electromagnets (24), and the directional control valves (3, 4) are put together from pilot control valve (14) and main control valves (3) arranged on a common axis, where by the pilot control valve (4) switches the main control valve (3) by means of a separate pressure medium supply to be found on an additional control pressure line, in which accepting borings (2) are suited for the acceptance of main control and pilot control valves (3, 4) constructed as cartridges which are plugged together.

Abstract: A hydraulic shield support is disclosed with at least two adjustable-length hydraulic props supporting a dedicated shield, which are connected through a control bank to a hydraulic fluid supply and borne on base shoes, and to which a pressure in excess of the pressure of the hydraulic fluid may be applied in the set condition of the shield support. In order to provide almost any pressure level at each shield support at a deep face in a simple way, the shield support has at least one pressure intensifier located in a hydraulic pipe system between the hydraulic fluid supply and the hydraulic props, with an oscillating intensifier piston in the form a differential piston effecting the increase in pressure. The low pressure inlet of the pressure intensifier is connected to the setting pressure pipes upstream, and its high-pressure outlet downstream, of a hydraulically-releasable non-return valve.

Abstract: A lift cylinder arrangement is disclosed for a hydraulic support frame for underground mining. The support frame has a lift cylinder for lifting the base shoes during advancing, which is supported on the one hand on a return rod and on the other hand, in a pivoting manner, with an end supporting head to a drawbar connected to the base shoes. In order to allow a simple, rapid and reliable connection between the supporting head and the drawbar, the supporting head is connected to the drawbar by a plug-type locking system comprising two plug-type locking elements, which include first locking notches on the drawbar, and arranged complementarily thereto second locking notches on the supporting head, whereby the plug-type locking elements engage in at least one of the locking notches with clearance.

Abstract: An electro-hydraulic assembly for use in underground mining is disclosed. The assembly includes a hydraulic component, such as a valve block for an underground self-advancing roof support, as well as actuators and/or sensors which have a housing and can be connected or are connected via a data-transmission system to a control unit. A function (e.g. withdrawing the support, setting, advancing, or the like) can be activated at the hydraulic component by each actuator, and/or a hydraulic state associated with a measuring point of the hydraulic component or another measured variable associated with the self-advancing roof support can be measured by each sensor. A reader unit is associated with each actuator and/or sensor in its respective housing, and an information element or transponder is associated with the hydraulic component for each function, each control valve, or each measuring point.

Abstract: A hydraulic cylinder (10), especially as a pit prop or moving cylinder unit in underground mining, with a locking ring (16) arranged on an outer cylinder tube (11) sealing it at its end with a lead through for an axially movable rod element (12; 13) accommodated in it. The locking ring (16) is provided in the lead through surrounding the rod element (12; 13) with a sealing arrangement (22) resting on the outer side (34) of the rod element (12; 13). The sealing arrangement (22) has a guide ring (29) provided with grease grooves (33) open to the outer side (34) of the rod element (12, 13), which can, be supplied with lubricant for the grease grooves (33) via a lubricant line (35) accessible on the outside on the hydraulic cylinder (10) and which is arranged in an accepting groove (40) formed interlocking ring (16) between an axially inner and an axially outer collar (38; 39).

Abstract: In the directional control valve (10) for support mechanisms in underground mining, the valve piston (16) is guided seal free in the valve seat carrier (15) between the high pressure connection (P) and a sealing ring (22) and thus permits an overflow of high pressure fluid from the high pressure connection (P) to the return flow connection (T) on opening the valve (10). The valve (10) thus achieves an opening and closing characteristic with negative overlapping and so provides gentle switching processes, so that switching impacts with high pressure peaks do not arise.

Abstract: In an electrohydraulic control device especially for use in the hydraulic systems of advancing support frames of underground mining equipment a valve or valve block 1 is provided with accepting borings 2 and connection borings 27, 28 for load connections (6, 7), which lie on one axis M and merge directly into each other. The accepting space formed by the accepting borings 2 is constructed similarly for all the directional control valves, put together from a pilot control valve 4 and a main control valve 3. In the valve block 1 additionally to the high pressure line P and the return flow line T there runs a control pressure line PST, with which the pressure medium supply for switching the main control valve 3 is effected. The construction according to the invention of the valve block reduces manufacturing costs and offers substantial advantages in the assembly of the directional control valves.

Abstract: In the directional control valve (10) for support mechanisms in underground mining, the valve piston (16) is guided seal free in the valve seat carrier (15) between the high pressure connection (P) and a sealing ring (22) and thus permits an overflow of high pressure fluid from the high pressure connection (P) to the return flow connection (T) on opening the valve (10). The valve (10) thus achieves an opening and closing characteristic with negative overlapping and so provides gentle switching processes, so that switching impacts with high pressure peaks do not arise.

Abstract: A valve arrangement (10) for hydraulically actuated machinery installations, especially for powered support assemblies in underground mining, with hydraulically actuated working valves (12, 13, 14) to control hydraulic cylinders (11) or other hydraulically actuated machinery units of the machinery installation and with pilot valves (15) controlling the working valves. In order to avoid the pilot valves (15) and working valves (12, 13, 14) entering an unstable operating condition in the event of a falling off of pressure in the hydraulic fluid supply to the valves, and opening and closing in an uncontrollable and undesired manner, the pilot valves (15) are attached to their own pressure medium supply (17), separate or separable from the hydraulic fluid supply (20) to the working valves (12, 13, 14), so that pressure variations in the hydraulic fluid supply circuit do not affect the pressure medium for the switching of the working valves (12, 13, 14), but the pressure in them is maintained largely constant.

Abstract: A hydraulic cylinder (10), especially as a pit prop or moving cylinder unit in underground mining, with a locking ring (16) arranged on an outer cylinder tube (11) sealing it at its end with a lead through for an axially movable rod element (12; 13) accommodated in it. The locking ring (16) is provided In the lead through surrounding the rod element (12; 13) with a sealing arrangement (22) resting on the outer side (34) of the rod element (12; 13). The sealing arrangement (22) has a guide ring (29) provided with grease grooves (33) open to the outer side (34) of the rod element (12, 13) which can be supplied with lubricant for the grease grooves (33) via a lubricant line (35) accessible on the outside on the hydraulic cylinder (10) and which is arranged in an accepting groove (40) formed interlocking ring (16) between an axially inner and an axially outer collar (38; 39).

Abstract: The double telescopic prop comprises an outer cylindrical casing tube 1, an inner tube 2 which is displaceable therein and a piston rod 3 which can be extended therefrom. The hydraulic fluid for extending the two prop stages is conveyed through a connection 14 to the piston 5 of the inner tube 2 and is conveyed via a bottom valve to the piston 7 of the piston rod 3. The prop is retracted if hydraulic fluid flows via the connection 17 into the outer annulus 11 between the cylindrical casing tube 1 and the inner tube 2. A size ratio of 8.8:1 at most, which is favourable for the retraction of the prop, exists between the area of the inner tube 2 and the ring area of the annulus 11.

Abstract: The electrohydraulic control unit comprises at least one 3/2 directional control valve 2 which is switched by an electromagnet 3 connected to an intrinsically safe power supply. The components of the 3/2 directional control valve 2 are arranged in a valve cartridge 18 inserted into the valve casing 1 on a common axis and with adjustable clearance with respect to the electromagnet 3. The control plunger 12 of the electromagnet 3 transmits the switching force through a precompressed spring buffer 4 to the stoppers 24, 30 of the 3/2 directional control valve 2.

Abstract: The body (1) of the hydraulically trippable check valve for mine support hydraulics according to the invention contains: a valve poppet (13) biased in the closing direction by a spring (22); a control piston (17) which can be acted on by a hydraulic control pressure, causing the poppet (13) to be lifted off its seat (11); and an initial relief valve (20, 21) which can be tripped by the control piston (17) against its spring closing force. Matters are arranged so that the control piston (17) which can be acted on by the hydraulic control pressure is dimensioned in terms of piston surface area (17') so that the poppet (13) of the check valve cannot be lifted off its seat (11) until the opening of the initial relief valve has caused a predetermined initial relief of operating pressure on the high-pressure side.