Holder for collar of workpiece or tool

In combination with a tool or workpiece having a mounting collar centered on an axis and formed internally with an shoulder, a holder comprising:

• a drive sleeve also centered on the axis and fitted over the collar;
• a plurality of angularly spaced jaws in the sleeve having first ends each formed with a face, the jaws being displaceable radially between an outer locking position with their faces bearing on the shoulder and an inner freeing position with their faces out of engagement with the collar;
• means including an axially displaceable actuating member in the sleeve for moving the jaws between their inner and outer positions;
• and
• a plurality of axially extending retaining fingers each having a rear end secured in the sleeve and a front end with a rearwardly directed face, the front ends normally lying in an outer holding position with their faces bearing on the shoulder and being elastically deformable independently of the jaws via relative axial movement of the tool or workpiece and the drive sleeve into an inner releasing position with their faces out of engagement with the collar.