Clamping device

A clamping device for machine tools, the device being provided with a power-operated chuck for holding a workpiece, and clamping jaws adapted to be actuated using the clamping device by means of a movement converter and an axially moveable draw rod, wherein the clamping device is provided with an electric drive motor having a changeover function connectable to the movement converter for triggering clamping movements,

• wherein
• the drive motor is provided with a switching element which is adjustable by axial control in a middle position and in one or both limit positions, and which is driven directly or by intermediate elements, the switching element being connectable in a positive or non-positive arrangement to components of the clamping device, in particular the power-operated chuck, in one limit position, and to an axially movable adjustment element in the other limit position, wherein the adjustment element is connected to an auxiliary device of the machine tool, or is connected to the power-operated chuck in order to rotate the power-operated chuck in a position-oriented manner, the rotationally fixed connection being effected by means of components of the clamping device, and the switching element is adapted to be locked and unlocked on a machine spindle of the machine tool (2) in one or both limit positions.