SELF-ADVANCING ROOF SUPPORTS

摘要

A self-advancing mine-roof support 10 has a double acting hydraulic ram 28 within the support connected to the support base 12 and to a relay bar 24 for coupling to an anchorage forward of the support and a ram 31 for lifting of the support base in relation to the relay bar. The rearward end of the relay bar is pivotally connected approximately to the midpoint of the hydraulic ram 28 and the relay bar 24 is of box section construction.