Variable amplitude drill.

摘要

A vibratory core drill comprises a housing (11) adapted for connection to a drill string and a variable amplitude rotor (10) rotably mounted in the housing (11), the variable amplitude rotor (10) comprising a central shaft (1), an inner shell (2), the inner and outer shells (2) and (3) being capable of rotation relative to one another and capable of being locked in any desired relationship and released. The variable amplitude rotor enables the amplitude of oscillation to be varied to cope with formations of different characteristics, eg, sand and clay. The drill is suitable for use in drilling core samples for evaluating the mineral potential of deposits and for environmental monitoring to detect possible contamination.