Patent ID: 8439135

Claim:
A down-the-hole drill hammer assembly comprising: a housing; a drill stem at least partially housed within the housing, the drill stem including: a distal end slidably engaged with a drilling lug segment and a proximal end opposite the distal end, an abutment surface proximate the distal end, and a first thrust shoulder proximate the abutment surface; wherein the drilling lug segment is movable between an initial configuration and an extended configuration, the drilling lug segment including a proximal end engageable with the first thrust shoulder; and a pilot drill bit mounted to the drill stem, the pilot drill bit including: an open proximal end for receiving a portion of the drill stem, a lateral wall that includes an opening having the drilling lug segment positioned therein, and a distal end that includes a cutting face, wherein the drill stem is movable between first and second positions within the pilot drill bit, and in moving to the second position, the abutment surface moves toward the distal end of the pilot drill bit and engages and moves the drilling lug segment to the extended configuration.