Mine gallery support withdrawal appts. - has frame mounted on floor member with swinging member carrying withdrawal member

摘要

The mine gallery support withdrawal system uses a withdrawal unit consisting of a floor member (1) supporting a withdrawal member (10) at the top. The unit has a rectangular frame seen in end elevation, with side plates (9), between which are telescopic rams (3) which swing an upper bridging member (4). This has a cross member (5) above it, which carries the withdrawal member (10). The length of the latter spans two channels (15), and it has a groove (16) at the rear, to engage one of the channels. The whole is steadied by a cylinder (7) at the bottom, acting against an end anchorage, and by side cylinders (11) which slope sideways for connection to the bottom of the arch.