ANORDNING FOR BORRNING AV HAL OVER HELA BORRHALSBOTTENYTAN

摘要

The invention is a device for drilling holes over the entire bottom surface of the drill hole. The device consists partly of a drill shaft (2) fixed drill crown (1) with a canal (15) for irrigation to the bottom of the drill hole, and partly of a forming device (3) mounted above the drill crown (1) for formation of the hole wall, which is intended to delimit a column between the drill hole wall and drill shaft (2) wall. The drill shaft's (2) inner cavity above the drill crown (1) houses a holder (5) filled with damming material, which is intended to supply damming material to the drill crown (1). This (1) is equipped with an axial opening (8), the diameter of which is greater than the inner diameter of the holder (5) and proportioned to receive the bottom end of the holder (5).