HAMMER AND CASING PIPE FOR DOWN HOLE

摘要

A hammer and a casing pipe for perforating the ground are provided to prevent the guide member from being separated by forming a ring mounting groove from the outer peripheral side to the inside and to preclude the constructed member from being damaged by placing the guide member keeping a predetermined gap between the constructed member and the perforating bit. A hammer(500) with a perforating bit(200) for perforating the ground is composed of a guide member(551) installed with a sliding combining part(554) vertically and slidably combined with a member constructed at the outer peripheral surface of the hammer. The guide member is rotatably combined for the outer peripheral surface of the hammer. The guide member contains a rotary ring(552) formed to cover the hammer. A ring mounting groove(540) is recessed at the area where the rotary ring is mounted.