VORRICHTUNG ZUR BETAETIGUNG EINES SPANNKOPFS

摘要

In a draw-bar mechanism for moving the collet of a chuck or the like on a spindle of an automatic turning machine toward its axial clamping position and for thereafter closing the collet more slowly with greater force about a tool or workpiece to be clamped, motion is transmitted from an actuating sleeve to a draw bar or like control member by spherical thrust members movably confined between three faces obliquely inclined relative to each other. A first face is fixed relative to the spindle assembly and has one section parallel to the axis and another axially contiguous section obliquely inclined relative to the axis, the two sections merging in an exposed edge. A second face is fixed relative to the control member, and the third face is fixed relative to the actuating sleeve and has two axially consecutive sections obliquely inclined relative to each other. The faces are dimensioned and shaped in such a manner as to permit tilting of the thrust members about the exposed edge during movement of the control member in the axial collet-clamping direction while the thrust members engage the face of the actuating sleeve.