Earth auger and its auger head null for cast-in-place pile

摘要

PURPOSE:To exactly remove excavated soil by a method in which spiral screw blades are provided to the peripheral side of a hollow shaft and a spiral band in parallel with the shaft is formed on the peripheral side of the blade in an auger head, and a bit to be closed when reversely turned is provided to the auger head. CONSTITUTION:An auger head 9 consists of a hollow shaft 5, a spiral screw blade 6, and a spiral band 30 provided to the peripheral side of the blade 6. Two left- and right-handed excavating bits 31 are pivotally supported on the tip of the blade 6 in a freely opening or closing (on a shaft 32) manner. A bottom plate 35 is also attached to the portion other than the lower end bit 31 of the head, and a synergestic mechanism such as stopper 36 is also provided to the bit 31 because the bit 31 is allowed to open during normal rotation but to close during reverse rotation. The head 9 is attached to the tip of an earth auger body 4 for excavating work. In pulling up the auger at the end of excava tion, the bit 31 turns to close the opening of the bottom plate, permitting exca vated soil to be removed exactly.