Piercing point rotary drill bit

Claim 1

IN A DRILL BIT ADAPTED FOR DETACHABLE CONNECTION WITH, AND AS THE EXCAVATING TERMINUS OF, A ROTATABLY DRIVEN TUBULAR DRILL LINE, THE COMBINATION OF A GENERALLY CYLINDRICAL HARD RIGID BODY FORMED WITH A PLANE CIRCULAR FACE DRICAL HARD RIGID BODY FORMED WITH A PLANE CIRCULAR FACE PERPENDICULAR TO THE AXIS OF SAID BODY, SAID FACE BEING DISPOSED AT ONE END OF SAID BODY, A STEM OF REDUCED DIAMETER PROJECTING FROM THE OPPOSITE END OF SAID BODY AND ADAPTING SAID BODY FOR REMOVABLE AND REPLACEABLE CONNECTION THEREOF WITH A DRILL LINE EXTENDING COAXIALLY THEREWITH, SAID BODY HAVING A PLURALITY OF SOCKET RECESSES OPENING ONTO SAID CIRCULAR FACE, SAID CIRCULAR RECESSES BEING DISPOSED WITH THE MEDIAL AXIS THEREOF LYING IN CONCENTRIC CIRCULAR LOCI CONCENTRIC WITH THE AXIS OF SAID BODY, A PLURALITY OF AXIALLY TAPERED AND POINTED ELONGATED TIP MEMBERS, SAID TIP MEMBERS BEING FORMED OF TUNGSTEN CARBIDE MATERIAL, AND BEING FIXED IN SAID SOCKET RECESSES WITH THE POINTS THEREOF PROJECTING AXIALLY BEYOND SAID CIRCULAR FACE, THE POINTS OF SAID TIP MEMBERS TERMINATING AT LEAST SUBSTANTIALLY EQUI-DISTANTLY FROM SAID CIRCULAR FACE, SAID BODY HAVING A CYLINDRICAL PORTION EXTENDING FROM SAID CIRCULAR FACE TOWARD SAID STEM AND AN INWARDLY TAPERED PORTION EXTENDING FROM SAID CYLINDRICAL PORTION TOWARD SAID STEM AND A SHOULDER EXTENDING BETWEEN SAID INWARDLY TAPERED PORTION AND SAID STEM, SAID BODY HAVING A FRUSTO-CONICAL CAVITY THEREIN, SAID CAVITY TAPERING INWARDLY IN THE DIRECTION FROM SAID CIRCULAR FACE TOWARD SAID STEM AND SAID CAVITY BEING COAXIAL WITH THE AXIS OF SAID BODY, SAID STEM AND THE ADJACENT PORTION OF SAID BODY HAVING A CYLINDRICAL INLET PASSAGEWAY EXTENDING THERETHROUGH, ONE END OF SAID INLET PASSAGEWAY OPENING ONTO THE END OF SAID STEM AND THE OTHER END OF SAID PASSAGEWAY MERGING INTO AND BEING COEXTENSIVE WITH THE ADJACENT END OF SAID CAVITY, SAID CAVITY BEING CONCAVELY SHAPED AT THE END THEREOF REMOTE FROM SAID END ADJACENT SAID INLET PASSAGEWAY, SAID BODY HAVING AN OUTLET PASSAGEWAY THEREIN EXTENDING AT LEAST SUBSTANTIALLY PERPENDICULARLY FROM SAID CIRCULAR FACE TO SAID CONCAVELY SHAPED END OF SAID CAVITY, SAID OUTLET PASSAGEWAY BEING TAPERED INWARDLY INTERMEDIATE SAID CONCAVELY SHAPED END OF SAID CAVITY AND SAID CIRCULAR FACE AND IN THE FLUID PATH DIRECTION THEREBETWEEN, SAID OUTLET PASSAGEWAY BEING DISPOSED IN ECCENTRIC RELATION TO SAID AXIS OF SAID BODY BUT PARALLEL THERETO, SAID BODY HAVING A PLURALITY OF CIRCULARLY CONCAVE CHANNELS EXTENDING AXIALLY OF SAID BODY AND SYMMETRICALLY THEREABOUT, SAID CHANNELS OPENING ONTO AND FORMING PART OF THE PERIPHERY OF SAID CYLINDRICAL PORTION AND SAID INWARDLY TAPERED PORTION OF SAID BODY, THE EDGES OF SAID CHANNELS ADJACENT THE OUTER PERIPHERY OF SAID CYLINDRICAL AND INWARDLY TAPERED PORTIONS OF SAID BODY BEING BEVELLED.