Abstract: A bit retention system for a hammer drill including a housing (41), a drive sub (44) connected to lower end of the housing, and a bit retainer (50) having an upper end suspendable from a shoulder of the drive sub and a lower end including a radially inwardly projecting bit retention rim (52). The upper end of a locking sleeve (70) has internal features (78) that are engageable with external features (76) at the lower end of the housing to prevent relative rotation, and a lower end sized (82) to overlap the upper end (90) of the retainer. The lower end of the locking sleeve is welded to the retainer, thus locking the threads on the drive sub from unscrewing from housing threads. The drive sub and retaining member are pinned together to stop separate rotation.

Abstract: A bit retention system for a hammer drill including a housing (41), a drive sub (44) connected to lower end of the housing, and a bit retainer (50) having an upper end suspendable from a shoulder of the drive sub and a lower end including a radially inwardly projecting bit retention rim (52). The upper end of a locking sleeve (70) has internal features (78) that are engageable with external features (76) at the lower end of the housing to prevent relative rotation, and a lower end sized (82) to overlap the upper end (90) of the retainer. The lower end of the locking sleeve is welded to the retainer, thus locking the threads on the drive sub from unscrewing from housing threads. The drive sub and retaining member are pinned together to stop separate rotation.