Patent ID: 9719306
Date: 2017-08-01
CPC Classifications: E21B

Claim:
1. A drill bit for a percussive hammer comprising: an elongated shank having opposed ends; a head disposed at a first end of the shank; an array of lengthwise extending spline portions defining outwardly extending retention lugs at or toward a second end of the shank, each of the retention lugs having opposed side faces, a top land and first and second end faces, at least one side face of at least one lug of the retention splines being blended into the shank of the bit, and each of the first and second end faces of each retention lug is blended into the top land; and a plurality of lengthwise extending driven splines longitudinally spaced from the array of retention lugs located toward the head end of the bit, each of the driven splines having a top land perceptibly wider than the top land of each lug of the retention splines.