Clamping device

1. A clamping device for clamping a work piece, comprising:

a chuck;

a collet positioned inside the chuck; and

a bayonet fastener operatively arranged so that the collet is fastenable in the chuck and is removable from the chuck solely by manual operation of the bayonet fastener without the use of auxiliary tools, wherein the bayonet fastener includes a manually operated activation ring and a bayonet ring operatively connected to the activation ring for securing the collet to the chuck, wherein the activation ring is rotatable and is operatively arranged so that rotation of the activation ring moves the bayonet ring between a closed position in which the bayonet ring secures the collet on the chuck and an opened position in which the bayonet ring releases the collet on the chuck, and wherein the bayonet ring has spaced apart radial grooves and the clamping device further includes pins projecting in a radially inward direction from inside the activation ring to engage in the radial grooves of the bayonet ring to transmit a rotational movement of the activation ring to the bayonet ring.

2. The clamping device according to claim 1 , wherein the activation ring and the bayonet ring arc arranged concentrically on the chuck, and wherein the bayonet ring is arranged inside the activation ring.

3. The clamping device according to claim 1 , wherein the bayonet ring has one front face including brackets which extend radially toward an inside into a cavity enclosed by the bayonet ring and which arc operative to secure the collet.

4. The clamping device according to claim 3 , wherein the collet includes webs ending at an outer surface of the collet in a radial direction and which are separated by grooves to form a ring-shaped arrangement, and wherein in the closed position of the bayonet ring the brackets of the bayonet ring rest against the webs thereby securing the collet inside the chuck, and in the opened position of the bayonet ring the brackets are located in regions of the grooves so that the collet is removable from the chuck.

5. The clamping device according to claim 4 , wherein the webs and the grooves adjoin a front face of the collet by which the collet is inserted into the chuck.

6. The clamping device according to claim 1 , wherein the collet comprises a plurality of identical collet segments and a plurality of axially extending elastic elements that respectively connect adjacent collet segments.

7. The clamping device according to claim 6 , wherein, during the closing of the bayonet fastener, the collet segments move uniformly in the radial direction over the complete length and the elastic elements are compressed uniformly over the complete length.