| 摘要 |
1,110,955. Advancing mine roof supports. KLÍCKNER-WERKE A. G. Aug. 20, 1965 [Aug. 21, 1964], No.35750/65. Heading F1P. In a mine roof support system wherein a series of self-advancing roof support assemblies are arranged in groups a, b and each assembly comprises an A-frame and a B-frame connected together by a hydraulic advancing ram 7, the pressure supply for extending the props of the frames and for operating the ram 7 originates from two pumps x, y connected to lines I, II which cross over between groups to pass alternately through the A-frames of a group and the B-frames of the next group. The operation of each group of support assemblies is controlled by an associated assembly of fourway valves 1-4. The valves 1, 2 are normally in a position in which they communicate the pressure supply from the pumps x, y to their associated frames A, B, and are operated to allow advance of their associated frames. If valve 2 of group a is operated (as shown) the B-frames thereof are connected to a return 8 and pressure liquid from the line I is directed to the valve 3 and no longer flows to the alternate frames of subsequent groups. These frames, however, continue to support the roof since liquid is retained therein by non-return valves. The valve 3 is normally in a closed position wherein it connects the pressure release lines of the frames A, B to exhaust 10. To cause release of the B-frames of group a the valve 3 is operated and to cause it to advance valve 4 is then operated to connect both ends of the ram 7 to the pressure supply I. During advance of the B-frames of group a the valve 1 thereof directs the full pressure in line II to the A-frames of group a and to the alternate frames of the other groups. |
