| 摘要 |
A friction roof bolt comprising a generally annular body which from end-to-end has a slot through its thickness. Means is provided for fixing the body in a radially elastically compressed state so as to make possible insertion thereof in a hole 12 of diameter substantially smaller than the normal outer diameter of the body. After such insertion, the body is caused to expand to anchor by frictional engagement with the surrounding wall of the hole 12. The annular body may be held in its compressed state by binding it with wire or glass fibre tape, or bonding or welding a tape along the slot to hold it closed. after insertion in the hole 12, a cutting tool is drawn along the slot by a wire 14 to release the binding or tape. <IMAGE> |
