STEERABLE GROUND PIERCING TOOLS

摘要

A steerable ground piercing tool includes an elongated outer housing having a lengthwise extending bore and an inner assembly at least in part disposed within the outer housing. The inner assembly includes a rotatable chisel having a longitudinally extending shaft at least in part disposed within the housing bore. The chisel has a first end defining an asymmetric tip and a second end defining a first impact surface for receiving a reciprocating action impact to drive the tool through the ground. The inner assembly further includes a conversion mechanism to selectively convert upon activation thereof at least a first portion of the reciprocating action imparted to the first impact surface into combined reciprocation and rotation of the tool.