Mine gallery rock anchor - is locked in hole by collar with tapered chamber housing balls compressed by end plug

摘要

The rock anchor is a mine gallery cladding anchorage rod (4) which can be ridged helically and is held in place against a pressure plate (5) in contact with the rock (6) passing through a hole in its middle and into a hole in the rock. A steel holding sleeve (1) has a clearance hole at the front, and a large dia. tapped hole (7) at the rear. The part between them slopes outwards to form a chamber (8), which is filled with steel balls (2). These are retained by an externally threaded plug (3), which is screwed inwards to compress the balls and lock the sleeve in position. An alternative design has a sleeve which is closed at the front and rear, except for a clearance hole, and fitted with a locking screw at the side.