Drill for rotary percussion drilling

Claim 1

A DRILL BIT AND DRILL ROD ASSEMBLY, SAID DRILL BIT HAVING A LOWER CUTTING PORTION AND AN UPER SHANK PORTION, A LONGITUDINAL BORE IN SAID SHANK PORTION, SAID DRILL ROD EXTENDING INTO SID BORE, A DEPRESSION HAVING LIMITING END SHOULDERS IN THE SIDE OF SAID DRILL ROD AT A DISTANCE FROM THE LOWER END THEREOF, A LOCKING MEMBER SECURED TO SAID DRILL BIT AND EXTENDING INTO SAID BORE AND DEPRESSION, SAID LOCKING MEMBER HAVING A SUBSTANTIALLY SMALLER DIMENSION IN THE DIRECTION OF THE LONGITUDINAL AXIS OF SAID DRILL BIT THAN SAID DEPRESSION AND THE DISTANCE BETWEEN THE LOWER END SHOULDER OF SAID DEPRESSION AND THE END OF SAID DRILL ROD BEING SUBSTANTIALLY SMALLER THAN THE DISTANCE BETWEEN SAID LOCKING MEMBER AND THE BOTTOM OF SAID BORE, THE LOWER PORTION OF SAID BORE HAVING A CROSS SECTIONAL SIZE AND SHAPE CORRESPONDING TO THE SIZE AND SHAPE OF THE LOWER END PORTION OF SAID DRILL ROD, SAID BORE ADJACENT THE UPPER END OF SAID SHANK PORTION HAVING A BEVELED INNER SURFACE THAT IS INCLINED UPWARDLY AND OUTWARDLY RELATIVE TO THE AXIS OF SAID SHANK PORTION, SAID SHANK PORTION HAVING A LOWER OUTER CYLINDRICAL SURFACE ON ONE SIDE THEREOF ADJACENT TO THE LOWER END THEREOF AND AN UPPER OUTER CYLINDRICAL SURFACE ON THE OPPOSITE SIDE THEREOF ADJACENT TO THE UPPER END THEREOF, SAID CYLINDRICAL SURFACES BEING APPROXIMATELY CONCENTRIC WITH THE AXIS OF SAID SHANK PORTION, SAID CUTTING PORTION HAVING AN ECCENTRIC CUTTING EDGE THAT EXTENDS RADIALLY BEYOND THE EXTENSION OF SAID LOWER CYLINDRICAL SURFACE, SAID SHANK PORTION HAVING ALSO A FIRST BEVELED OUTER SURFACE ADJACENT TO THE UPPER END THEREOF OPPOSITE TO SAID UPPER OUTER CYLINDRICAL SURFACE AND A SECOND BEVELED OUTER SURFACE ADJACENT TO THE LOWER END THEREOF RADIALLY OPPOSITE TO SAID LOWER OUTER CYLINDRICAL SURFACE, SAID OUTER BEVELED SURFACES AND SAID BEVELED INNER SURFACE ALL BEING SUBSTANTIALLY PARALLEL TO AN AXIS THAT IS INCLINED WITH RESPECT TO THE AXIS OF SAID SHANK PORTION AND SAID FIRST BEVELED OUTER SURFACE ADJACENT TO THE UPPER END OF SAID SHANK PORTION BEING SUBSTANTIALLY ALINED WITH THE OUTERMOST EXTENSION OF SAID ECCENTRIC CUTTING EDGE.