Equipment for High Speed Transversal Perforations of Variable Lengths on Continuous Forms in Movement

An equipment for high speed transversal perforations of variable lengths on continuous forms in movement, comprising a blade support with at least a perforating blade, a blade contrast having at least one projecting profile of contrast for the perforating blade, and servomechanisms for rotating the support blade and the blade contrast to carry a perforating blade against the projecting profile, in synchronism with the form, wherein

• the perforating blade has a length suitable for perforations of maximum length (L) of the form;
• the blade contrast comprises a hollow cylinder of low rotational inertia, and in which said hollow cylinder defines the projecting profile or the projecting profiles, on a lateral surface of the hollow cylinder;
• the projecting profiled has sectors on respective angular positions (φ) of the hollow cylinder and having axial extensions dependent on the respective angular positions (φ);
• and
• the servomechanisms include a contrast servomechanism provided for selecting an angular position of the hollow cylinder, such to position, for the contrast with the blade, a sector of the projecting profile having axial extension equal to the requested length the perforation;
• and in which
• the said hollow cylinder is rotatable around a support shaft, without any mechanical contact, according to a structure constituting a radial air bearing of pneumostatic type.