GB1065881A - Mine roof support remote control systems - Google Patents

Abstract

1,065,881. Hydraulic apparatus. COAL INDUSTRY (PATENTS) Ltd. March 6, 1964 [March 8, 1963], No.9326/63. Heading F1P. A plurality of hydraulic advancing mine roof support units are arranged in at least two groups (2 - - 6), (7, 8 and 1) Fig.1 (not shown) and the units of each group are advanced in a predetermined sequence, units (2, 7) being master units which on receiving a signal from a remote control point serve to initiate the advancing sequence and the system also includes means for producing a signal at the control point indicating completion of the sequence of operations. Each unit other than the master unit comprises a ram (64) Fig. 3 (not shown) which advances the prop frame (22a) when pressure fluid from a supply line (26) is admitted to the pulling end of the ram cylinder through a control valve (60) when the latter is opened by pilot pressure transmitted to a chamber (60a) through a line 28 leading from a solenoid operated valve 25 of the master unit or through a line from the previously actuated unit. The outlet of control valve (60) also leads to a pilot chamber (20a) to open a normally closed prop release control valve (20) located between the prop frame (63a) and a return line (29). On completion of the prop unit advance a trigger valve (68) serves to pressurize a pilot chamber (20b) thereby closing valve (70) and also supplying pressure to the props to re-set the same. The resulting pressure rise then opens a trip valve (80) and pressure is transmitted along a line (67) to initiate advance of the succeeding unit. The master unit is the last of the group to be actuated when pilot pressure is transmitted to chamber (30a) Fig. 2 of the ram control valve (30) which is thereby opened to connect supply line (26) to a line (31) leading to the pulling side of ram (24) and leading to the pilot chamber (40a) of the prop release valve (40) which acts as does valve (70) of the remaining units. Ram control valve (30) also has a pilot chamber (30b) which on energizing a solenoid valve (23) is connected to supply line (26) resulting in opening of valve (30) and connecting line (26) to a line (32) leading to the conveyer pushing side of the ram (24). An abutment (37) on the ram and a pressure switch operated after resetting the props send signals to the remote control point. In a modification each master unit selectively controls the sequence of its own group or of the units of an adjacent group.