Abstract: A clamping device with a housing, a spindle which is rotationally mounted in the housing, and an elastic clamping element, the clamping element being movable by application of a force out of a first position in which the spindle can be turned into a second position in which the spindle is clamped by the clamping element. The clamping element has an inner cylinder which surrounds the spindle to be clamped, an outer cylinder which is located coaxially to the inner cylinder, and a membrane which connects the inner cylinder to the outer cylinder. The clamping element is annular and roughly cup-shaped with an opening in the middle of the clamping element so that the inner cylinder surrounds the spindle to be clamped. The clamping element is shaped and arranged such that, by applying a force to the clamping element the curvature of the membrane can be changed.