| 摘要 |
PURPOSE:To eliminate the need for providing machine tool-side feeding mechanism by constructing an internal thread member having a tap retaining part, which is installed relatively rotatably but relatively immovably to a holder body, in such a way that it does not rotate when said holder is installed to a spindle. CONSTITUTION:In a process is which the outer peripheral tapered surface of a taper shank 12 is fitted in the inner peripheral tapered surface of a spindle, the rotation of an internal thread member 30 is prevented since a positioning pin 44 and a block 56 are fitted into engaging grooves and, as the positioning pin 44 is retracted and a key 50 is removed from a groove 52, relative rotation between a plate 42 and a holder body 10 is allowed. At the same time, an acting pin 110 is projected from the end of the positioning pin 44 to operate a touch switch 114, generating an electric signal, the spindle is advanced causing a tape 84 to approach a workpiece W. Then, due to the rotation of a spindle, a lead screw shaft 62 is rotated through an excessive load preventing device 66, carrying out internal thread machining. Thereby, the use of a machine tool-side feeding mechanism can be eliminated. |
