Anchoring of roof bolts.

摘要

This invention relates to the anchoring of roof bolts in drill holes by the roaming of enlarged sections (3) within a preformod drill hole (2) so that a shoulder (4) of rock is formed at the junction of the drilled and reamed sections of the hole. The expansion head of a roof bolt is expanded within the hole so that the segments (42) of the expansion shell engage and positively lock against the shoulder (4). In this way an improved lock for a roof bolt in a drill hole is obtained and the roof bolt resists dislodgement under load.