BIT ASSEMBLY FOR A HAMMERING DRILL

摘要

A bit assembly for a hammering and rotating drill, in which assembly the drill body (1) is arranged to drill essentially the middle portion of the hole and in the drill body (1) mounted one or more hammering bit (2), (3) is arranged to drill the outer circle of the hole. The outer circle of the hole drilling bits (2), (3) are arranged to drill a drilling surface, which locates further behind in the drilling direction than for the drill body (1) meant drilling surface (L1) and that the mentioned bits (2), (3) are further mounted in a drill body (1) formed counter cavities (7), the axial directions (S) of which have either the same direction as the drilling direction has or deviate outwards from it and mentioned bits can at least a part of their way out of the counter cavities be transported out in the direction which deviates from the axial direction (S) of the counter cavity.