SELF SHARPENING CUTTING STRUCTURE FOR EXPANDABLE EARTH BORING APPARATUS USING IMPREGNATED AND MATRIX MATERIALS

摘要

A tool for enlarging a borehole that includes an elongated tubular body; at least one movable arm affixed to the tubular body, the at least one movable arm comprising an outer surface formed of at least one of a matrix material and an abrasive material; and at least one actuating member for expanding at least one movable arm fro m the collapsed state to an expanded state is disclosed.