Patent ID: 6676787
Filing Date: 2004-01-13
Classification: B29D

Abstract:
A method for controlling the amount of perforated surface area on a perforated cylindrical outer surface of a hollow cylindrical drum, through which air can be drawn into the hollow cylindrical drum having an inner surface, to provide a suction adhering surface for holding sheet materials on the outer surface of the drum, the cylindrical drum being closed at opposite ends with end plates to prevent airflow into the drum through the opposite ends, the cylindrical drum having a diameter and an axis, and the method characterized by the steps of:providing two axially movable baffle plates within the drum, each having a diameter substantially equal to the diameter of the drum; varying the axial positions of the baffle plates to control a portion of the perforated surface area between the baffle plates through which air can be drawn into the hollow cylindrical drum; providing, within the drum, a circumferentially moveable curved cylinder element conforming to the inner surface of the perforated cylindrical drum; and controlling the amount of perforated surface area through which air can be drawn into the hollow cylindrical drum by circumferentially positioning the curved cylinder segment adjacent a portion of the inner surface of the hollow perforated cylindrical drum.