False drum with a variable area vacuum-surface

摘要

A false drum servers used in the manufacture of tires having a hollow cylindrical drum with a perforated surface on the drum through which air is drawn. The drawn air creating a suction surface for holding flat or sheet materials that are to be cut before transferring onto a tire building drum. When smaller pieces of flat materials are being held on the drum, the perforations that are not covered allow air to flow freely into the drum, thereby reducing the suction adhering effect of the perforated surface. The present invention provides methods and apparatus for varying the amount of perforated area through which air can be drawn into the drum, thereby changing the amount of suction adhering surface area of the perforated drum.