Patent ID: 9592621
Date: 2017-03-14
CPC Classifications: B26D,B26F,Y10T

Claim:
1. An equipment for high speed transversal perforations of variable lengths on a continuous form 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, wherein the blade support and the blade contrast have rotation axes parallel one another and possibility of rotation around the respective rotation axes transversally to a direction of movement (A) of the form, and servomechanisms for rotating the blade support and the blade contrast to carry a perforating blade against the projecting profile, in synchronism with the form, wherein the perforating blade extends transversely to the form and has a length suitable for transversal 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 profile has sectors on respective angular positions (φ) of the hollow cylinder from a reference position with axial transversal extensions parallel to said rotation axes and of increasing length or of decreasing length dependent on the respective angular positions (φ) from said reference position; and the servomechanisms include a contrast servomechanism provided for selecting an angular position (φ) of the hollow cylinder from said reference position, such to position, for the contrast with the perforating blade, one of said sectors of the projecting profile having one of said transversal axial extensions equal to the requested length of the perforation for perforations of the continuous form having freely selectionable lengths; and in which the hollow cylinder is rotatable around a support shaft according to a structure including radial ducts of said support shaft under compressed air, open toward said hollow cylinder and constituting a radial air bearing of pneumostatic type between the hollow cylinder and said support shaft.