GB1333425A - Mine roof supporting systems - Google Patents

Abstract

1333425 Advancing mine roof supports K M GROETSCHEL 15 Dec 1970 [18 Dec 1969] 59576/70 'Heading E1P In an advancing mine roof support system for a longwall face comprising a row of supports each including a number of hydraulic supporting props and an advancing means for advancing one unit when its props are depressurised while another unit of the support has its props urged against the roof, the system is provided with an arrangement of valve means and conduit interconnections whereby to advance a group of supports of the row progressively starting from one end of the group and continuing to the other, operation of the valve means on or for each support of this group in turn brings about advancement of a unit in that support and also a unit in an adjacent support of the group. The supports referenced n+1, n, n-1, n-2 in Fig. 2 of the Drawings are of the two-slip type and may be constructed as disclosed in Specifications 1198507 or 1198839 and adapted to be advanced by double-acting rams 35. The circuit includes a manually operable primary control valve block 10 and secondary valves 11, 12 which respectively control pressurisation of props 3, 13 of one unit of the support and props 1, 18 of the other unit of the said support, the various valves being interconnected to the props, a pressure source, the advancing rams and to one another by means of the circuit shown. The arrangement is such that as the cutter for example passes the support n the valve 10 is moved from the setting position of Fig. 2a (not shown) to that of Fig. 2e (not shown) whereby the props of the inner unit of the support n and the props of the outer unit of the support n-1 are depressurised and the rams 35 of these supports simultaneously energised to move the inner unit of the support n and the outer unit of the support n-1 towards the coal face. The props of both supports n and n-1 are now energised by an automatic or manual operation of the valve 10 and the operator will now operate the valve 18 on the next support n+1 to continue the sequence of operations set out above. The circuit described above with reference to Fig. 2 is adapted for an arrangement wherein the cutter cuts in one direction of traverse only but for an arrangement involving a cut in two opposite directions the modification disclosed with reference to Figs. 3, 3a to 3e (not shown) and involving alternating valves should be referred to. Fig. 4 (not shown) depicts a modified form of control valve block for use in either of the arrangements disclosed above. For further details of the circuit and modus operand! the Specification should be referred to.