Abstract: A clamping chuck for machine tools comprising a chuck body and a plurality of clamping jaws which can be displaced together radially by means of a drive comprising key rods is disclosed. An actuating mechanism comprising a releasing bolt is rotatably positioned in the chuck body, and a releasing key can be coupled to the releasing bolt, in order to displace the key rod between an upper working position and a lower jaw changing position. The key rod comprises locking means which enable the releasing bolt to rotate out of the rotary position corresponding to the lower jaw changing position of the key rod, into the rotary position corresponding to the upper working position of the key rod, when the toothing of the coupling yoke is engaged with the counter-toothing of an associated clamping jaw.

Abstract: A clamping chuck for machine tools comprises a chuck body and a plurality of clamping jaws which can be displaced together radially by means of a drive comprising key rods. An actuating mechanism comprises a releasing bolt which is rotatably positioned in the chuck body, and a releasing key which can be coupled to the releasing bolt, in order to displace the key rod between an upper working position and a lower jaw changing position. Said key rod comprises locking means which enable the releasing bolt to rotate out of the rotary position corresponding to the lower jaw changing position of the key rod, into the rotary position corresponding to the upper working position of the key rod, when the toothing of the coupling yoke is engaged with the counter-toothing of an associated clamping jaw.