Drilling tool comprises a removable bit secured against axial movement by locking devices that can be sheared off by axial forces acting on the bit

摘要

Drilling tool with a transition piece (2) connecting a removable bit (1) to a drilling string comprises replaceable locking devices (10) that secure the bit against axial movement and are received in radial recesses (11) in an endpiece (7) of the transition piece and engage with a receiving ring (8) on the bit through a sleeve (6) locked against the endpiece. The locking devices can be sheared off by axial forces acting on the bit.