SHIELD-TYPE ROOF SUPPORTING FRAME

摘要

A mine roof support for underground excavations includes a support adapted to engage the floor of the underground excavation, and a movable roof shield which engages the roof of the underground excavation. A movable rear shield is mounted on the support and is pivotally connected with the roof shield for relative movement thereto about a pivot axis. A pit prop arrangement is provided intermediate the shields and the support for moving the shields relative to each other about the pivot axis between a plurality of inclined positions in which the rear shield is inclined at different angles of inclination relative to the roof shield. A pair of abutment members are respectively provided on the shields for limiting relative movement of the latter beyond a predetermined one of the inclined positions in which the shields are inclined at a predetermined angle of inclination relative to each other.