Expanding collet

An expansive collet chuck body comprising:

• a collet body having radially extending receiving cutouts, that extend in an axial direction, and further having an annular recess;
• a plurality of radially extending clamping parts with respective planar counter guiding surfaces, said clamping parts being inserted into said receiving cutouts;
• a central mandrel having a substantially regular polygonal cross-section and being provided with flat guiding surfaces, said guiding surfaces resting at and within said counter guiding surfaces of said clamping parts;
• a pull member for being connected to said collet body, with said clamping parts for being reciprocally axially displaceable by said pull member to thereby achieve a radial clamping action between said guiding surfaces and said counter guiding surfaces;
• a means provided at said pull-member and said collet body for quick-releasing a connection between said pull member and said collet body;
• a radially extending cog provided at each one of said clamping parts, each said radially extending cog engaging said annular recess to axially couple said collet body and said clamping parts;
• and
• a means for preventing rotational displacement of said collet body relative to said mandrel comprising a catching cutout provided at said collet body and a catch provided at a spindle head, said catching cutout, in an operational position of said collet body, engaging said catch.