Rock bit

• Main Authors: MINIKUS, JAMES CARL, CAWTHORNE,CHRIS EDWARD
• Format: Patent
• Language: English; French; German
• Published: 14.12.1988
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

An inclined chisel crested insert (22) is disclosed for use on the gage row of a cone (18) for a rotary cone rock bit (10). The insert has different conical surfaces (42, 45) on opposite sides of the crown (44) of the insert. An elongate conically shaped gage cutting surface (42) of the insert provides point or line contact with a borehole wall (37) 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 elongate conical gage cutting surface of the chisel crest insert minimises gage insert wear and subsequent breakage by eliminating high cycle thermal fatigue.