Forepoled roofbar for longwall roof supports - has vertical piston drive at waste end which thrusts against roof via auxiliary bar

摘要

The forepoled bar for a longwall roof support can be extended by a piston drive and comprises a two arm lever vertically pivoted to the main roofbar. A vertically directed piston drive (6) situated at the waste end of the forepoled bar (5, 4) thrusts against the roof via an auxiliary bar (7). Preferably the forepoled bar forms a fork straddling the main roofbar (4), alternatively it may lie between the two parts of a divided roofbar. The forepoled bar rides tracks arranged on the main roofbar or roofbar parts, via fitted rollers.