Clamping mandrel for digital printing on can bodies

摘要

A mandrel to clamp a beverage can from the inside to precisely control the movement of the can during printing operations includes several clamping segments (2; 2a, 2b, 2c) that form an outward-facing cylindrical clamping area (16) so as to grip an internal surface of the can. As air pressure is reduced through the centre axial bore 4 of the rotatable shaft of the mandrel, the can is sucked on to the mandrel and suction is created in the space 9 so that the piston 10 moves toward the end of the mandrel and drags the conical elements 13 in one direction so that interacting conical elements 17, 19 slide with respect to each other to radially expand the clamping segments to grip the can. When positive pressure is applied to the axial bore, the clamping elements are radially moved so as no longer to grip the can and the synchronously the can is expelled off the mandrel.