A mechanical rotational drive has a bar-like torsion element, whereby the torsion element is firmly clamped with a first end in a bearing device. The torsion element can be pivoted with a second free end with respect to the clamped end about the longitudinal axis, forming a rotation axis, of the torsion element between a relaxed position and a tensioned position, whereby the length of the torsion element is reduced with respect to the relaxed position when the torsion element is brought into its tensioned position. A device for transmitting a torque into the torsion element or out of the torsion element is provided in the area of the free end, and a damping device is arranged in the axial direction of the torsion element at a fixed distance from the bearing device and adjacent to the free end of the torsion element, and a damping part is provided on the torsion element in the area of the free end of the torsion element, which damping part in the relaxed position is in friction engagement with the damping device and which in the tensioned position is not engaged with the damping device.