GB1131356A - Shifting device for longwall conveyors - Google Patents

Abstract

1,131,356. Advancing conveyers. GEWERKSCHAFT EISENHUTTE WESTFALIA. 6 June, 1966 [10 June, 1965], No. 25011/66. Heading B8A. [Also in Division F1] A conveyer-advancing hydraulic cylinder and piston device 2, Fig. 1, connected at one end to an hydraulic walking mine roof support structure 14 and at the other end to the conveyer 17 is controlled by a slide valve 1, Fig. 2, actuated by a spring-biased servo-piston 4 in open communication with the supply line 6 leading to the working chamber 5 of the props whereby during normal working the piston 4 is displaced against a spring 3 and sets the valve 1 to a position 9 in which pressure and return lines P, R, are connected to prop and conveyer ends respectively of cylinder 2 which is thus urged to its extended position, whilst when pressure in line 6 is relieved to release the props from the roof, the spring 3 sets valve 1 to a position 10 in which the pressure and return lines P, R are connected to the conveyer and prop ends respectively of the cylinder 2 which latter is free to move towards the conveyer during the advance of the props. The valve 1 may be manually set to a third position 8 in which the pressure line P is blocked and both ends of the cylinder are connected to the return line R. In a modification wherein the rod of the cylinder 2 merely abuts the conveyer 17 the valve 1 assumes position 8, Fig. 4, when pressure in supply line 6 is relieved and position 10 is obtained manually when it is desired to retract the cylinder from the conveyer. In a further modification two series-connected control valves 11, 11<SP>1</SP>, Fig. 6, are so inserted in the supply lines 6, 6<SP>1</SP> of adjacent frames of two support structures that the automatic charging of cylinder 2 is possible only when pressure exists in both lines 6, 6<SP>1</SP>.