| 摘要 |
PURPOSE:To aim at improvements in accuracy of tapping depth, by installing a clutch in position between a holder body and a lead screw shank, while cutting the transmission of turning torque at a forward end of the lead screw shank, in case of the tap holder which is attached to a spindle of a machine tool and taps an internal thread. CONSTITUTION:A tap holder with a lead screw shank, holding a tap 120, is attached to a spindle 24 of a machine tool, tapping an internal thread with rotation of the spindle 24. In this tap holder, there are provided with a holder body 10 to be locked to the spindle 24, an internal thread member 34, having a tapped hole in the center and being installed rotatably ion a relative way to the holder body 10 and disably in relative movement toward an axial direction at a position where it comes to concentricity with the holder body 10 and a rotation stopping device which engages this internal thread member 34 while stops rotation of the internal thread member 34 upon engaging a non- rotational member installed around the spindle 24 when the holder 10 is locked to the spindle 24. In addition, rotation torque of the holder body 10 is transmitted to a lead screw shank 80, making it go forward, while it comprises a clutch 104 which cuts transmission of the rotation at its forward end. |
