Rolling cone rock bit with wraparound spearpoints

Claim 1

IN A ROCK BIT HAVING A MULTIPLICITY OF ROLLING CONE CUTTERS MOUNTED THEREON WITH THEIR AXES OF ROTATION INCLINED DOWNWARDLY AND INWARDLY WITH RESPECT TO THE AXIS OF ROTATION OF THE BIT, WHEREIN EACH CUTTER HAS A CONICAL NOSE AT ITS SMALL END TERMINATING ADJACENT BUT SHORT OF SAID BIT AXIS, SUCH NOSE HAVING INSERTS OF WEAR RESISTANT MATERIAL PROTRUDING THEREFROM WITH BLUNT CUTTING TIPS AND WHEREIN SUCH INSERTS ARE DISPOSED AND DISTRIBUTED BETWEEN CUTTERS TO ROLL THROUGH ADJACENT AND OVERLAPPING ANNULI, THE INNERMOST SUCH ANNULUS BEING DEFINED BY AN INSERT FROM THE APEX OF ONE OF SAID CONICAL NOSES, THE IMPROVEMENT COMPRISING SLIGHTLY TRUNCATED ENDS ON ALL OF SAID NOSES AND SAID INSERTS OF WEAR RESISTANT MATERIAL PROTRUDING FROM THE CONICAL SURFACES AND SOME OF THE TRUNCATED ENDS OF SAID NOSES WITH THE CUTTING TIPS OF ALL INSERTS ADJACENT BUT SPACED AN APPRECIABLE RADIAL DISTANCE FROM THE BIT AXIS AT THEIR NEAREST APPROACH THERETO, SAID INSERT IN A NOSE APEX HAVING ITS CUTTING TIP PROTRUDING AXIALLY BEYOND THE CUTTING TIPS OF THE OTHER INSERTS AND SUCH OTHER CUTTING TIPS BEING DISPOSED IN AXIALLY SPACED CONCENTRIC ANNULAR ROWS OF PROGRESSIVELY INCREASING RADIUS SO THAT, AS ALL CONES ARE ROTATED THROUGH A COMMON POSITION, SUCH CUTTING TIPS OF THE NOSE INSERTS LIE WITHIN AND DEFINE A CONVEX SURFACE OF REVOLUTION SURROUNDING THE SMALL END OF THE CUTTERS, SAID RADIAL DISTANCE BEING SUCH AS TO ADAPT SAID BIT TO CUT A WELLBORE LEAVING A ROCK POST OF SUCH A RADIUS THAT THE POST DISINTEGRATES AS DRILLING PROGRESSES, THE NUMBER AND SPACING OF SAID INSERTS IN THE NOSES PROVIDING SUPPORTING CONE MATERIAL BETWEEN ADJACENT INSERTS HAVING A MINIMUM DIMENSION OF ABOUT 1/8 INCH.