Abstract: A clamping tool serving for clamping a workpiece on a support by a bar system constructed of a number of mutually pivotal bars comprising an activation bar for at operation making the bars pivot mutually between an initial position and locking position, a clamping bar having at least one clamp shoe for pressing against the workpiece in the locking position of the bar system, and a base for mounting the bar system on the support. The bar system furthermore comprises two toggle joints arranged to simultaneously or almost simultaneously assume their dead point positions when the bar system at activation is taken from the initial position to the locking position. In the dead point positions the two toggle joints form an angle with each other.