GB1180578A - Advancing Mine Roof Supports - Google Patents

Abstract

1,180,578. Advancing mine roof supports. PODMOSKOVNY GOSUDARSTVENNY PROEKTNO KONSTRUKTORSKY I EXPERIMENTALNY INSTITUT GORNOGO MASHINOSTROENIA. 6 March, 1967, No. 10436/67. Heading E1P. A mine roof contacting member carried by the head of a hydraulic prop 1 Fig. 2 is held against the roof at a predetermined pressure which is independent of variations in the working height during prop advance by connecting the working chamber 9 of the prop to the main pressure supply line 14 through a distributing valve 13, a pressure line 19 which also supplies the prop advancing jack 7, a throttle valve 16 and a main pressure actuated valve 11 whereby when the prop meets a hole in the roof extra pressure fluid is supplied to chamber 9 through valve 11 at a pressure which is limited by the setting of a by-pass governor valve 17 connected to a return line 20, and when the prop meets a projection on the roof, fluid from space 9 is relieved through valve 17. At the end of prop advance valve 13 is reversed thereby connecting line 19 and hence jack 7 to the return line 15 and retracting the actuator 12 of valve 11, and at the same time main pressure in line 20 opens a valve 18 and the valve 11 to gain access to prop chamber 9. The valve 13 is finally positioned so that both lines 19, 20 are unpressurized. Valve 10 is a high pressure relief valve. In a modification prop advance is effected by connecting the main pressure line 14 through valve 13 Fig. 3 to lines 23, 24. Line 23 is connected to jack chamber 22 and to the actuator of a valve 27 to close the same, and line 24 is connected to the upper chamber 29 of prop 1, the actuator of valve 11 to open the same and through a throttle 30, a line 31 and valve 11 to the prop chamber 9 the pressure in which is maintained at a value determined by the setting of by-pass valve 17 which opens into a line 26, valve 13 and the return line 15. At the end of prop advance, valve 13 is reversed, lines 23, 24 are connected to the return line 15 and lines 26, 31 are connected to the supply line 14 whereby valve 27 is opened by its spring 28, and prop chamber 9 is connected to the main pressure line 14. Finally valve 13 is positioned to connect lines 26, 31 as well as line 23, 24 to the return line 15.