Patent GB-1063455-A (GB)
Title: Roof support assembly suitable for use in mines
Inventor: PAWLING FRANK
IPC: E21D23/26
Filed: 1964-05-15
Abstract: 1,063,455. Advancing mine roof supports. DOWTY MINING EQUIPMENT Ltd. May 11, 1965 [May 15, 1964], No. 20382/64. Heading F1P. In a mine roof support assembly wherein a series of roof supports each having props (4) and an advancing jack (6) and each being controlled by an associated valve assembly, Fig. 3 (not shown), operative on receipt of a fluid pressure signal through a line (15) from the preceding roof support in the series to cause its support to undergo and advancing operation, the valve assembly is automatically operable, after the satisfactory completion of the advancing operation to send a signal to the next support in the series to initiate its advance and remotely operable means are provided which when operated in the event of the support not advancing satisfactorily cause the signal to be sent. If a signal is received from the preceding left hand support in the series the left hand portion of the line (15) is pressurized whereby a valve (29) is opened to pressurize a line (32) and thereby cause the support to advance. Pressurization of the line (32) actuates a piston (59) which rotates a lever (57) to open a prop release valve (55) so that pressure fluid expelled from the props (4) passes therethrough to a return line (30). The pressure in the line (32) also passes to the advancing jack (6) through non-return valves (41, 68) whereby the released props (4) are advanced until a prop re-setting valve (46) is opened by the satisfactory completion of the advance. The opening of the valve (46) results in pressurization from the line (32) of a line (47) which in turn actuates a piston (61) to cause closure of the prop release valve (55). The props (4) are consequently re-set against the roof, pressure fluid passing thereto from the line (47) through a pressure reducing valve or restrictor (49) and non-return valves (51). When a satisfactory pressure in the props (4) is achieved the pressure in a line (62) connected thereto becomes sufficient to open a sequence valve (45) to allow pressure fluid in a branch control line (13) to flow via a safety valve (65) to a chamber (21). Pressurization of the chamber (21) causes closure of valves (25, 26) and the opening of valves (16, 17) whereby a branch pressure line (11) is communicated via a chamber (28) to valves (29, 31) which thereby close so that pressure in the line (32) is lost through a restriction (69). The right hand side of the line (15) is also pressurized from the chamber (28) to provide a signal so that the next support in the series undergoes an advancing operation. If the support fails to advance or re-set satisfactorily the pressure in the line (62) does not reach a value sufficient to open the sequence valve (45). To allow the advance of the supports to continue the remotely operated means is actuated to pressurize the branch control line (13) to a higher value so that the valve (46) and/or a self-latching valve (39) is operated to communicate pressure fluid through the line (62) or a line (43) to open the sequence valve (45). The sequence valves (45) of each advanced support and any self-latching valves (39) operated during an advancing sequence are held open by fluid trapped between non-return valves (44, 63) and a locking valve (64). At the end of an advancing sequence the locking valves (64) are operated by pressurizing the line (13) to an even higher pressure. Each support may be advanced by manual operation of the lever (24) of an adjacent roof support.