| 摘要 |
The invention relates to a combination of a tool holder having a socket member with a cylindrical axial bore, and a tool shaft releasably received therein. A driving element is displaceably mounted in the socket member so as to be movable between an extended position in which part of the driving member extends into the axial bore, and a retracted position in which the driving member is retracted from the bore, and the driving element is biased towards its extended position by spring means. The tool shaft received in the tool holder has a transversely extending recess receiving the driving element in its extended position, whereby the tool shaft is locked in the tool holder. Adjacent to the free end of the tool shaft the said recess defines an abutment surface cooperating with an inner surface part of the driving element in its extended position so as to prevent axial withdrawal of the tool shaft from the axial bore of the socket member. According to the invention the said abutment surface of the recess and the said surface part of the driving element are shaped so as to tend to rotate the tool shaft in the normal rotational direction of the tool associated with the tool shaft when the abutment surface and said surface part are pressed together by axially directed forces, whereby the risk of inadvertent release of the tool shaft from the tool holder may be eliminated. The cooperating surfaces or surface parts of the tool shaft and the driving element, respectively, may be flat surfaces extending obliquely in relation to the longitudinal axis of the tool shaft, or one of or both of the said surface parts may be curved. |
