Self-drilling expansion anchor bolt

Claim 1

AN ANCHOR BOLT FOR INSERTION IN A WALL; SAID BOLT COMPRISING AN EXPANSIBLE SLEEVE HAVING A THREADED END PORTION AT ONE END AND A FLANGE PLATE AT ITS OTHER END WITH AN EXPANSIBLE COLLAR PORTION THEREBETWEEN, SAID COLLAR PORTION HAVING AXIALLY EXTENDING SLITS THEREIN, A BOLT FITTED THROUGH SAID SLEEVE AND HAVING THREADS FOR ENGAGING THE THREADS OF SAID THREADED END PORTION, SAID THREADED END PORTION ADAPTED TO ADVANCE TOWARD SAID FLANGE PLATE WHEN SAID BOLT IS ROTATED IN A PRESELECTED DIRECTION RELATIVE TO SAID SLEEVE WHEREBY TO EXPAND SAID COLLAR PORTION OF SAID SLEEVE, SAID BOLT BEING PROVIDED AT ONE END WITH A HEAD PROJECTING BEYOND SAID FLANGE PLATE AND BEING PROVIDED WITH A POINT AT ITS OTHER END, SAID POINT HAVING A SUBSTANTIALLY FLAT REMOVABLE CUTTER ELEMENT THEREON HAVING CUTTING EDGES FOR BORING A HOLE THROUGH A WALL WHEN ROTATION IN SAID PRESELECTED DIRECTION IS IMPARTED TO SAID BOLT, SAID BOLT BEING PROVIDED INTERMEDIATE ITS ENDS WITH A DIAMETRICALLY REDUCED PORTION TO SLIDABLY FIT WITHIN SAID THREADED END PORTION.