Method and apparatus for correcting stack lean in a zig-zag folded web

• US RE32,331 E
• Filed: 10/01/1984
• Issued: 01/13/1987
• Est. Priority Date: 06/22/1981
• Status: Expired due to Fees

• Current Assignee: Paper Converting Machine Company (Barry-Wehmiller Group Incorporated)
• Original Assignee: Paper Converting Machine Company (Barry-Wehmiller Group Incorporated)
• Inventors: Schuning, George F., McKeefry, Jerry L., Fulk, James B., Bradley, John J.
• Primary Examiner(s): Heinz, A. J.
• Application Number:
  US06/656,722
• Time in Patent Office: 834 Days
• Field of Search: 493/410, 493/430, 493/399, 493/433, 83/863, 83/865, 83/879, 83/880, 83/884, 270/39
• US Class Current: 493/399
• CPC Class Codes: B26D 5/22 having the cutting member and work feed mechanically connected
• CPC Class Codes: Y10T 83/0424 By stretching
• CPC Class Codes: Y10T 83/0481 Puncturing
• CPC Class Codes: Y10T 83/0519 Cyclically varying rate of tool or work movement
• CPC Class Codes: Y10T 83/323 With means to stretch work temporarily
• CPC Class Codes: Y10T 83/6579 With means to press work to work-carrier

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.

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, .Iadd.by producing an amount of motion in said web passing through the said perforating means greater than variables which cause a leaning stack, .Iaddend.the duration of .[.said.]. .Iadd.the .Iaddend.cycle of said .Iadd.cyclically varying additional .Iaddend.force extending at least over the .Iadd.travel of .Iaddend.web length between three folds .Iadd.said cyclically varying force being a substantially continuously acting sinusoidal force and adjusting the cyclically applied force to cancel the amount of cyclic motion from the machine and paper variables, the adjustment of said cyclically applied force being achieved by adjusting the phase relationship between said cyclically applied force and said cyclic motion resulting from the machine and paper variables.Iaddend..

2. The method of claim 1 in which a plurality of superposed webs are advanced through the perforating means, and independently cyclically applying a force to each web for the purpose of changing the distance between selected perforations as the web passes through the perforating means.

3. The method of claim 1 in which a plurality of side-by-side webs are advanced through the perforating means, and independently cyclically applying a force to each web for the purpose of changing the distance between selected perforations as the webs pass through the perforating means.

4. The method of claim 1 wherein a web constraining means is applied before the web perforating means and a second web constraining means is applied after the web perforating means.

5. The method of claim 4 in which a force is cyclically applied perpendicular to said web between the perforating means and one of said constraining means.

6. The method of claim 4 in which one constraining means includes pulling the web downstream of said perforating means so as to develop a predetermined tension therein, said force being operable to cyclically change the tension in said web.

7. The method of claim 4 in which one constraining means includes pulling the web downstream of said perforating means, said force being operable to change the length of the path between said one constraining means and said perforating means.

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.]. .Iadd.substantially continuously acting sinusoidally .Iaddend.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, .Iadd.the duration of a sine cycle of said force extending at least over the web length between three folds, .Iaddend.and adjusting the .[.cyclically.]. .Iadd.sinusoidally .Iaddend.applied force to cancel the amount of cyclic motion from the machine and paper variables .Iadd.while said web is being advanced, the adjustment of said sinusoidally varying force being achieved by adjusting the phase relationship between said sinusoidally varying force and said cyclic motion resulting from the machine and paper variables..Iaddend. .[.9. The method of claim 8 in which said transverse force cyclic

9. application is sinusoidal..]. 10. The method of claim 8 wherein said web

12. webs after folding. .[.13. The method of claim 8 in which the adjustment of said cyclically applied force is achieved by adjusting the time relationship between said cyclically applied force and said cyclic motion

10. is equipped with longitudinally extending lines of weakness. 11. The method of claim 10 in which said longitudinally extending line of weakness is either a slit or a longitudinal perforation and occurs after one of

11. said constraining points. 12. The method of claim 11 wherein said web is longitudinally perforated and the resultant web separated into discrete

14. Iadd.7. Apparatus for correcting stack lean in a zig-zag folded web comprising a frame, means on said frame defining a web path and web constraining means spaced apart in said path,

a perforator in said path between said constraining means for perforating said web on approximately equally longitudinally spaced lines,

an eccentric roll rotatably mounted on said frame between said web constraining means, and

means operably associated with said frame for rotating said eccentric roll to provide a substantially continuously acting sinusoidally varying force on said web having a sine cycle whose duration extends at least over the web length between three folds, said sinusoidally varying force producing an amplitude of motion greater than the amplitude of the cyclic motion resulting from the machine and paper variables which cause a leaning stack, and speed varying means operably associated with said rotating means for changing the phase of said sinusoidally varying force relative to the lines of perforation to cancel said cyclic motion..Iaddend. .Iadd.18. The apparatus of claim 17 in which said speed varying means includes a differential drive unit interposed in said rotating means..Iaddend. .Iadd.19. Apparatus for correcting stack lean in a zig-zag folded web comprising a frame, means on said frame defining a web path and web constraining means spaced apart in said path,

a perforator in said path between said constraining means for perforating said web on approximately equally longitudinally spaced lines to provide a form length between adjacent lines of perforation,

an eccentric roll rotatably mounted on said frame between said web constraining means, said frame providing means to partially wrap said web about said eccentric roll to provide constant web contact therewith,

means operably associated with said frame for continuously rotating said eccentric roll to provide a substantially continuously acting sinusoidally varying force on said web having a sine cycle whose duration extends over an even number of form lengths, said sinusoidally varying force producing an amplitude of motion greater than the amplitude of the cyclic motion resulting from the machine and paper variables which cause a leaning stack, and differential means operably associated with said rotating means for changing the phase of said sinusoidally varying force relative to the lines of perforation to cancel said cyclic motion..Iaddend.

13. resulting 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.]. .Iadd.substantially continuously acting sinusoidally .Iaddend.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.Iadd., said additional force producing an amplitude of motion greater than the amplitude of the cyclic motion resulting from the machine and paper variables which cause a leaning stack, said additional force having a sine cycle whose duration extends at least over the web length between three folds, said further means including speed differential means for adjusting the phase relationship between said additional force and said cyclic motion to cancel said cyclic motion.Iaddend.. .[.15. The apparatus of claim 14 in which said further means includes a roll for increasing the tension in said web..]. .[.16. The apparatus of claim 14 in which said further means includes roll means for changing the web velocity by shifting the web longitudinally..].