| 摘要 |
In a screw driver with a turning tool placed at the front end of a shank which is torsionally connected with a handle, the turning tool can be reliably prevented from slipping off the head of the screw to be turned by the fact that the turning tool is embraced by a jaw chuck with at least two holding jaws in the form of spring arms of a shifter collar which can be moved in the axial direction on the shank, the spring arms being spreadable in the radial direction against their inherent elasticity by means of butting faces of the shank, and fixable against each other by means of a cooperating radial locking gear which can be released by butting faces of the shank. The shifter collar is fixable against the shank by means of a cooperating axial locking gear, and is connected with a control element which can be moved in the axial direction against the shank, has a limited relative movability against the shifter collar, and is provided with butting faces releasing the axial locking gear.
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