Patent ID: 7484445

Claim:
A perforating equipment for continuous paper forms comprising a contrast roller substantially tangent to the movement surface of the form, a perforating blade carried by a blade support provided for rotation in a condition of interference with said form against the contrast roller for the execution of transversal weakening perforations on the form in movement, said form having a given width and being provided for being longitudinally cut into continuous forms of half width, wherein the contrast roller and the blade support are rotatably supported by side bearings and have respective rotation axes parallel one another and slightly inclined with respect to a reference axis perpendicular to the direction of movement of the form; wherein the perforation blade is defined by a helical cutting edge with fine teeth having an inclination angle equal to the angle of inclination of said rotation axes with respect to the reference axis for a progressive perforating in a first direction from a side edge of said form; and wherein said equipment comprises two sets of perforating blade and contrast roller arranged one behind the other along the direction of movement of the paper form; said equipment further comprising a moving device engaging the perforated form downwardly with respect to the sets of perforating blade and contrast roller and two respective servomechanisms responsive to position indications of the form for independently rotating the blade support of said two sets of perforating blade and contrast roller from a condition of disengagement of the perforation blade to the condition of interference and to the condition of disengagement; said servomechanisms providing a peripheral velocity of the perforation blade of said two sets of perforating blade and contrast roller, at the moment of the perforation, equal to the moving velocity of said paper form; wherein the perforating blade of one of the two sets of perforating blade and contrast roller extends along the respective blade support for a length equal to a first half of the given width of the paper form for executing a weakening perforation on a first half of the continuous paper form; and wherein the perforating blade of the other of the two sets of perforating blade and contrast roller extends along the respective blade support for a length equal to a second half of the paper form for executing a weakening perforation on a second half of the continuous paper form independently of the perforation on the first half of the form; the perforating blade and the contrast roller of the one of the two sets of perforating blade and contrast roller and the contrast roller of the other of the two sets of perforating blade and contrast roller and the respective helical edges of said perforating blades having opposite inclinations with respect to the reference axis, to begin the perforations from opposite side edges of said paper form, staffing from the edges of the paper form adjacent to the side bearings.