Web processing apparatus

Abstract

A web tensioning assembly is configured to exert a tension on a web in a process direction and to balance the tension across a width of the web extending substantially in a direction perpendicular to the process direction. A web processing apparatus includes such a web tensioning assembly.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 60 / 960,952, filed on Oct. 22, 2007, the entirety of which is expressly incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a web tensioning assembly configured to exert a tension on a web in a process direction and to balance the tension across a width of the web extending substantially in a direction perpendicular to the process direction. The present invention also pertains to a web processing apparatus comprising such a web tensioning assembly.[0004]2. Description of Background Art[0005]Web tensioning assemblies that exert a tension on a web in a process direction are known in the background art. An example of such assembly is a suspended roller assembly. Such assembly comprises a roller rotatably mounted on an axis that is mounted on two linkages, which are mounted f...

AI Technical Summary

Benefits of technology

[0021]In another embodiment, the roller of the web tensioning assembly is rotatable over a limited portion of an axial revolution. The interfacing between the web and the web guide may be rolling or sliding, or any combination of these interfacing types. By allowing a partial rotation of the roller, the web tensioning assembly is prevented to apply a too large frictional shear tension on the web.

[0022]In another embodiment, the roller of the web tensioning assembly is rotatably fixed in an axial direction with respect to the suspension, thereby creating a sliding interface between the web guide and the web. The web slides along the contacting surface of the web while the web is being transported in the process direction. In case of sliding, interfacing between the web and the web guide, the contacting surface of the web guide, which contacts the web during the transport of the web in the process direction, is preferably smooth and applies a low frictional force in the process direction.

[0023]In a farther embodiment, the web tensioning assembly comprises a drag linkage extending between the frame and an eccentric location at an axial end portion of the roller, such that an axial rotation of the roller is prevented. By mounting an element, such as a drag linkage, between the frame on which the web tensioning assembly is mounted and a location of the roller, which lays at a distance with respect to the axis of axial rotation of the roller, the axial rotation of the roller is thereby prevented. It is found that locating the drag linkage at an end portion of the roller, e.g. the sides of the roller, near the outer surface of the roller, the drag linkage is most efficient, as this applies the largest mechanical arm to prevent a rotation of the roller.

[0024]In a further embodiment, the drag linkage is selectably engaged and disengaged with the roller, thereby selectably enabling a sliding or a rotating interfacing between the web guide and the web, respectively. The selection may, e.g. be implemented as

Problems solved by technology

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