Hydraulically operated advancing pit prop system - has vertical members interconnected in staggered pattern by upper and lower advancing cylinder pairs

摘要

An advancing pit prop system has a set of units, each with a floor member and a roof member interconnected by vertical telescopic supports (11) front and rear. The front supports of each unit are interconnected by advancing cylinders (14) sloping sideways, and the rear supports are similarly connected, the vertical supports of the unit being in advance of those each side, in a staggered arrangement. - Each vertical is attached to an adjacent vertical by an upper cylinder and a lower cylinder. All these cylinders (14) slope at an acute angle to the horizontal. Each end set is connected by a sliding guide to the face conveyor.