Signode Corporation

Hans Weitekamper

Donald L Van Erden

Manuel C Enriquez

An apparatus and method for producing an oriented plastic strap having a predetermined desired thickness for use in connection with the strapping of packages or the like, is disclosed. A sheet workpiece is conducted into a nip defined between a pair of milling and stretching rollers wherein one of the rollers is rotated at a lineal surface velocity which is greater than the lineal surface velocity of the other roller, and the rollers are rotated in opposite directions. One of the rollers effectively brakes or retards one of the surfaces of the sheet workpiece while the other one of the rollers effectively accelerates the other one of the surfaces of the sheet workpiece as the workpiece passes through the nip defined between the rollers whereby the workpiece is simultaneously milled and stretched. Additional heating is provided in connection with the surface of the sheet workpiece which is exposed to the ambient air prior to entry of the workpiece into the nip defined between the pair of rollers such that both surfaces will have similar temperature levels so as to exhibit similar density properties, and still further, the edge portions of the sheet workpiece are also heated so as to advantageously control the degree of flatness of the sheet material or workpiece across the width thereof. The flatness quality of the sheet workpiece can also be achieved through means of specially contoured milling rollers defining the zero gap assembly nip, or by means of specially contoured extrusion dies, whereby the edge portions are rendered thinner as compared to the central portion of the sheet workpiece such that upon milling and stretching of the workpiece, which operations tend to thicken the edge portions of the sheet workpiece, the edge portions will exhibit thickness dimensions commensurate with the thickness dimension of the central portion of the sheet workpiece.

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Lincolnshire, IL, United States of America

Hans Weitekamper