UNDER REAMING PILE BORE EXCAVATING BUCKET AND METHOD OF ITS EXCAVATION

An under reaming pile bore excavating bucket by which an under reamed part of a pile bore is excavated and the excavated soil is moved into the bucket for easy removal of the soil. In use, the bucket is lowered to the bottom of an already excavated straight pile bore; side apertures of the bucket are opened; the slidable wing drill bits are rotated and moved downward and outward along guide rails to excavate an under reamed part. The excavated soil is taken into the bucket through the side apertures and openable bottom apertures. When the drill bits reach their lowermost position, the drill bits are rotated reversely to house the drill bits again into the bucket and lastly the side apertures are closed. The soil within the bucket is raised from the excavated pile bore. In particular, a drive shaft is spline engaged with an outer pipe fixed to the center of the bucket body for allowing the slidable bits to rotate and further move downward or outward.