Assembly to recover a lost drilling rod, in underground mining and tunneling, has a metal sleeve with an inner threading, to engage the screw at the end of the missing rod for extraction

摘要

The system to hunt for a lost drilling rod, in underground mining and tunneling, has a stable sleeve (2) as a hollow cylinder of a metal or metal alloy which is not larger than the drilling crown at the leading end of the drilling rod being sought. It has an inner diameter which is not smaller than the maximum outer diameter of the missing drilling rod. The sleeve is open at one end side (3) and, at the other end side wall (4), there is a coupling (5-7) in a force fit for release attachment to a drilling rod. At the inner side a threading (9) engages the outer side of the advance screw at the lost drill rod. The free axial length of the sleeve interior ensures that a full rotation of the screw is caught by the inner thread.