Clamping Device for Film Rolls

A clamping device for receiving and clamping a film roll, comprising a winding core and a film reel arranged on the winding core, wherein the clamping device can be moved from an open position, in which the film roll can be inserted into the clamping device or removed from the clamping device, into a clamping position, in which the film roll is clamped in the clamping device,

• wherein the clamping device comprises a grooved shaft with receiving grooves arranged in the longitudinal direction offset at the same angular distance, a screw gear formed from a ring nut and a lock nut, and clamping levers arranged radially offset at the same angular distance,
• wherein an output member of the screw gear interacts with the clamping levers such that, when the clamping device is in the clamping position, the clamping levers bear on the base of the grooves of the grooved shaft and on the inner wall of the winding core, forming a clamping force, and
• wherein the grooved shaft has three receiving grooves arranged in the longitudinal direction offset by 120°, in which three clamping levers which are arranged radially offset by 120° engage, and
• wherein the ring nut has three groove-shaped bearing recesses arranged radially offset by 120°, which form pivot bearings for the clamping levers, and
• wherein, on its outer circumference, the lock nut has three groove-shaped positioning recesses offset by 120°, in which the clamping levers engage.