Method and apparatus for correcting stack lean in a zig-zag folded web
First Claim
1. In a method for correcting stack lean in a zig-zag folded continuous web having selected longitudinally spaced lines of transverse perforation and a fold at each said selected line, the steps of feeding a web through a means for transversely perforating the web while the web is under tension, and applying a cyclically varying additional force to the web for the purpose of changing the longitudinal length between said selected lines as the web passes through the perforating means, the duration of said cycle of said force extending at least over the web length between three folds.
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Accused Products
Abstract
Method and apparatus for correcting stack lean in a zig-zag folded web wherein a transverse force is cyclically applied to a traveling web so as to vary the motion of the web slightly as it passes through a transverse perforator.
10 Citations
16 Claims
- 1. In a method for correcting stack lean in a zig-zag folded continuous web having selected longitudinally spaced lines of transverse perforation and a fold at each said selected line, the steps of feeding a web through a means for transversely perforating the web while the web is under tension, and applying a cyclically varying additional force to the web for the purpose of changing the longitudinal length between said selected lines as the web passes through the perforating means, the duration of said cycle of said force extending at least over the web length between three folds.
- 8. In a method for correcting stack lean in a zig-zag folded continuous web having longitudinally spaced lines of perforation, the steps of transversely perforating said web by advancing same through a perforating means, constraining and advancing said web at two longitudinally spaced points on opposite sides of the means for perforating the web, applying a cyclically varying force perpendicular to the plane of said web to change the longitudinal length between the lines of perforation by producing an amount of motion in said web passing through the said perforating means greater than the cyclic motion resulting from the machine and paper variables which cause a leaning stack, and adjusting the cyclically applied force to cancel the amount of cyclic motion from the machine and paper variables.
- 14. Apparatus for correcting stack lean in zig-zag folded webs comprising means for advancing a web under tension along a predetermined path, a perforator operably associated with said path for transversely perforating said web on approximately equally longitudinally spaced apart lines, and further means operably associated with said path for applying a cyclically varying additional force to said web to cyclically and incrementally change the distance between where preselected perforations will be made before said web is engaged by said perforator.
Specification