Patent ID: 6419428
Filing Date: 2002-07-16
Classification: B23B,Y10T

Abstract:
A circular hole cutting device for cutting a circular hole in an object, said circular hole cutting device comprising:a bit holder attachable with a drive shaft of an electric power tool for detachably holding a bit to rotate the bit together with the drive shaft on a common axis; and a relatively rotatable part fitted to the bit holder and being relatively rotatable about the axis of the drive shaft, the relatively rotatable part having a pivot shaft which is located at a position offset from the bit in its radial direction and can be inserted into a center hole formed by the bit, wherein said relatively rotatable part includes a cover having a peripheral wall and an internal cavity which receives chips cut by said bit and a radial member fitted to the cover, wherein said radial member has at its far end said pivot shaft extending parallel to said bit and is fitted to the cover in such a way that the distance from the pivot shaft to the bit can be adjusted, and said peripheral wall is formed with a cutout which makes it possible to retract the pivot shaft into the cavity of the cover.