Drill bit

Claim 1

AN EARTH BORING DRILL BIT FOR CORRECTING A BORE HOLE WHICH HAS DEVIATED FROM A DESIRED SUBSTANTIALLY VERTICAL DRILLING REFERENCE LINE COMPRISING: A SUBSTANTIALLY CYLINDRICAL BIT BODY HAVING MEANS ON ONE END FOR CONNECTION WITH A DRILL STRING; A PAIR OF ARMS DEPENDING FROM THE PERIPHERY OF THE OTHER END OF SAID BIT BODY, EACH HAVING A VERTICALLY DISPOSED ARCUATE OUTER SURFACE GENERATED BY A RADIUS OF CURVATURE SUBSTANTIALLY EQUAL TO THAT OF THE BORE HOLE TO BE DRILLED; A SUBSTANTIALLY FRUSTO-CONICAL CUTTER MOUNTED FOR ROTATION ON EACH OF SAID ARMS, EACH CUTTER EXTENDING INWARDLY FROM SAID ARMS AND HAVING A PLURALITY OF TEETH THEREON, THE OUTERMOST RADIAL EXTENT OF SAID TEETH ON EACH OF SAID FRUSTO-CONICAL CUTTERS BEING NOT GREATER THAN THE OUTERMOST RADIAL EXTENT OF SAID ARCUATE OUTER SURFACES OF SAID PAIR OF ARMS WHEREBY SAID TEETH WILL BITINGLY ENGAGE ONLY THE BOTTOM OF THE BORE HOLE; A THIRD ARM DEPENDING FROM SAID BIT BODY ADJACENT SAID PAIR OF DEPENDING ARMS; AND A STRAIGHTENING CUTTER MOUNTED FOR ROTATION AT THE BASE OF SAID THIRD AMR HAVING A PLURALITY OF TEETH THEREON WHICH EXTEND GENERALLY RADIALLY RELATIVE TO THE BIT AXIS, THE OUTERMOST RADIAL EXTENT OF THE CUTTING TEETH ON SAID STRAIGTHENING CUTTER BEING GREATER THAN THE OUTERMOST RADIAL EXTENT OF SAID THIRD ARM AND SUBSTANTIALLY AS GREAT AS BUT NO GREATER THAN THE OUTERMOST RADIAL EXTENT OF SAID ARCUATE OUTER SURFACES OF SAID PAIR OF ARMS AND THE LOWER END OF SAID STRAIGHTENING CUTTER BEING POSITIONED SLIGHTLY HIGHER THAN THE LOWERMOST EXTENT OF THE TEETH OF SAID FRUSTO-CONICAL CUTTERS SO THAT THE CUTTING TEETH OF SAID STRAIGHTENING CUTTER WILL NOT ENGAGE THE BORE HOLE BOTTOM AND WILL OPERATIVELY BITTINGLY ENGAGE THE SIDE OF THE DEVIATED BORE HOLE NEAREST SAID DESIRED SUBSTANTIALLY VERTICAL DRILLING REFERENCE LINE.