| 摘要 |
A tool holder has a shank to be coupled to a machine spindle; a driven member adapted to receive therein a tool and having peripheral dents and recesses; a sleeve member for transmitting a torque from the shank to the driven member, the sleeve member having inclined slots and first balls loosely fitted in respective inclined slots; a spring-loaded, cup-shaped member having an inclined wall surface engageable with the first balls; and second balls lodged in respective recesses in the driven member, so as to impede the sliding movement of the cup-shaped member toward the first balls. When a tool receives an unusual rotational resistance during the rotation in the normal direction, then the sleeve member interrupts transmission of a torque to the tool, and in turn continues idling. The rotation in the normal direction, of the tool is resumed by rotating the sleeve member in the reverse direction and then in the normal direction. During the rotation in the reverse direction, of the sleeve member, a torque larger than that at the rotation in the normal direction, of the sleeve member is transmitted to the tool. |
