Patent GB-1023125-A (GB)
Title: Mining apparatus
Inventor: BOLTON DOUGLAS HERBERT HEWLETT
IPC: E21D23/16
Filed: 1963-07-22
Abstract: 1,023,125. Advancing mine roof supports. DOWTY MINING EQUIPMENT Ltd. July 21, 1964 [July 22, 1963], No. 28875/63. Heading F1P. In a mine roof support system, Fig. 1 (not shown), wherein a conveyer 1 is urged towards the working face 2 by jacks 11 associated with master roof supports 4, and each support 4 or 5 is automatically advanced in turn towards the conveyer 1 by its associated jack 9 when a signal is received through a pilot line 20 from the previous roof support in the series, the advance of the supports is halted if the conveyer is detected by control valves 10 (Fig. 2) not to have advanced a sufficient amount. Each control valve 10 is opened by an arm 32 when its associated jack 11 has urged the conveyer forward by a predetermined amount, the opening either allowing its own roof support to advance, or in the embodiment to be described, a preceding roof support. In the system described every fourth support is a master support each controlled by a valve assembly 16, the remaining supports being slave supports 5 each controlled by a valve assembly 17. Fig. 2 shows a master roof support 4 and its associated valve assembly 16 connected to the pilot line 20, a pressure supply line 18 and a return line 19. The lines 18, 19, 20 are connected to the valve assemblies of all the roof supports in a similar manner. The valve assembly 16 comprises valve units A, B controlling the conveyer advancing jack 11, valve units C, D controlling the support advancing jack 9, and valve units E, F controlling the setting and release of the support props 7. In the conveyer advancing condition of the valve assembly 16, levers 28, 35 are moved clockwise either manually or by automatic or manual pressurization of a line 29 connected to valve unit B and are maintained in the clockwise position by a spring actuated latch 30 whereby valve units A, C are opened and valve units B, D are closed. In operation, the pilot line 20 is pressurized from the preceding slave support 5, and its pressure is communicated through one of four non-return valves 44 to a valve 26. When the control valve 10 of the next master roof support is opened due to the predetermined advance of the conveyer pressure fluid passes therefrom to a line 22 to open the valve 26. Opening of the valve 26 communicates pilot pressure through a line 46 to release the latch 30 thereby allowing valve units C and A to close and valve units B and D to open. Hence a line 34 is pressurized from the supply line 18 through valve units C and D whereby valve unit F is opened allowing the props to de-pressurize through lines 39, non-return valves 42 a line 41 and the valve unit F. The support is then advanced towards the conveyer 1 by fluid supplied from the line 34 to the jack 9. When the support is fully advanced a prop resetting valve 49 is opened by the contraction of the jack 9, causing the pressurization from the line 34 of lines 51, 37. The pressure in the line 51 closes valve unit F, and the props 7 reset due to the pressure in the line 51 passing through non-return valves 38 and lines 39. The resetting of the props results in a build-up of pressure in the line 37 which when sufficient passes a non- return valve 53 to open a control valve 45 which is then locked in the open position by fluid trapped between the valves 53, 45. The opening of the control valve 45 opens the pilot line 20 to the valve assembly 17 of the adjacent slave roof support 5 which then undergoes an advancing operation, and simultaneously pressurizes a line 56 which returns valves D and B to the position shown. The control valve 10 may be actuated by manually pressurizing lines 57, 58 in the event of the conveyer failing to advance the predetermined amount. When all the supports have advanced the line 57 is pressurized to actuate a locking valve 55 which thereby allows the control valve 45 to close.