| 摘要 |
PROBLEM TO BE SOLVED: To provide a tap holder, minutely expandable in the axial direction, without looseness in the axial direction and the rotational direction, by adjusting an expansion quantity with a simple structure. SOLUTION: The tap holder includes a shank having a cylindrical part for arranging a plurality of through-holes in the circumferential direction, a holder body slidably fitted to the outside of the cylindrical part and forming a locking hole in a position corresponding to the through-holes, a bolt stored in the cylindrical part, having a head part and a shaft part and forming a tapered part on the lower side of the head part, a washer out-fitted to the shaft part of the bolt and forming a tapered part toward the head part of the bolt, a nut threaded into a screw distal end part of the bolt, a spiral spring out-fitted to the shaft part of the bolt, having one end allowed to abut on the washer and having the other end allowed to abut on the nut, and a steel ball stored in the through-holes, having one side supported by a circumferential part of the locking hole and having the other side supported by the tapered part of the bolt and the tapered part of the washer. COPYRIGHT: (C)2011,JPO&INPIT |
