Rotary panel cutter for cutting openings in a web

Abstract

The rotary panel cutter includes a cutter die that has a continuous upstanding knife blade. The cutter die has a body portion that is secured to a rotatable cutter shaft having a longitudinal axis. The cutter die knife blade has side edge portions that are perpendicular to the longitudinal axis of the cutter shaft and leading and trailing edge portions that are not parallel to the longitudinal axis of the cutter shaft. For cutting rectangular openings in a web the continuous upstanding knife blade has the configuration of a regular parallelogram wherein the length of side edges is the same and the length of the leading and trailing edges is also the same. The rotatable cutter shaft is mounted in a machine frame with its longitudinal axis at an angle other than 90.degree. with the center line of the web. The angle that the rotatable cutter shaft deviates from 90.degree. is preferably the same angle as the angle of deviation of the knife leading and trailing edges from the longitudinal axis of the cutter shaft. An anvil backing device, such as a rotatable anvil, is positioned adjacent to the rotatable cutter shaft and has an outer surface spaced from the rotary cutter die an amount slightly less than the thickness of the web material being cut. The longitudinal axis of the anvil is parallel to the longitudinal axis of the rotatable cutter shaft. A suitable conveying device, such as pull rolls, pull the web through the panel cutter between the cutter shaft and anvil and rotation of the rotatable panel cutter shaft cuts openings, such as windows, in the web.