DEVICE FOR CONNECTING A DRILL BIT TO A DRILL STRING PROVIDED WITH A PENETROMETER

摘要

Device for connecting a drill bit having a central bore to a drill string having at its lower part a retractable penetrometer, comprising an obturation member for the central bore, the lower part of which is provided with cutting elements, and adapted to block said central bore in response to the centrifugal force generated by the rotation of the bit, said obturation member leaving open said bore in the absence of rotation of the bit.