INCLINED CHISEL INSERTS FOR ROCK BITS

摘要

INCLINED CHISEL INSERTS FOR ROCK BITS An inclined chisel crested insert is disclosed for use on the gage row of a cone for a rotary cone rock bit. The insert has different conical surfaces on opposite sides of the crown of the insert. An elongated conically shaped gage cutting surface of the insert provides point or line contact with a borehole wall as opposed to a full surface contact with the wall as is common with state of the art flat sided gage row inserts. This inclined chisel insert also has advantages over the symmetrical chisel type gage insert in that it is designed to provide increased crest length while providing the desired gage surface angle. The conically shaped gage row inserts with offset chisel crest are less prone to frictional heating due to the point or line contact design. As a result, the elongated conical gage cutting surface of the chisel crest insert minimizes gage insert wear and subsequent breakage by eliminating high cycle thermal fatigue.