Apparatus for clamping a work piece

An apparatus for clamping a work piece in a well defined position within the operating area of a machine tool, comprising:

• a chuck means adapted to be fixed within the operating area of the machine tool;
• a work piece carrier means adapted to be fixed to said chuck means and to be clamped thereto;
• clamping means for clamping said work piece carrier means to said chuck means and adapted to be switched from a released condition to a clamping condition and vice versa;
• said chuck means comprising first positioning means and said work piece carrier means comprising second positioning means, said first and second positioning means being adapted to cooperate such as to define the position of said work piece carrier means relative to said chuck means along three coordinate axes each running perpendicular to each other as well as with regard to the angular orientation;
• said clamping means fixing said work piece carrier means to said chuck means once it is switched to said clamping condition to maintain said defined position;
• and
• said clamping means comprising a plurality of clamping device means each having a direction of activity along a linear path, each of said linear paths being located on or next to an imaginary cylindrical nappe intersecting said first and second positioning means;
• said clamping device means comprises a plurality of clamping ball means evenly distributed along the periphery of said chuck means and said work piece carrier means comprises a circular groove means located at its inner cylindrical surface, said clamping ball means being adapted to cooperate with said circular groove means.