Method of zig-zag folding and apparatus therefor

• US 3,947,013 A
• Filed: 07/22/1974
• Issued: 03/30/1976
• Est. Priority Date: 07/22/1974
• Status: Expired due to Term

• Current Assignee: Paper Converting Machine Company (Barry-Wehmiller Group Incorporated)
• Original Assignee: Paper Converting Machine Company (Barry-Wehmiller Group Incorporated)
• Inventors: Nystrand, Ernst Daniel
• Primary Examiner(s): Burr, Edgar S.
• Assistant Examiner(s): Heinz, A.
• Application Number:
  US05/490,239
• Time in Patent Office: 617 Days
• Field of Search: 270/39, 270/73, 270/79
• US Class Current: 493/422
• CPC Class Codes: B65H 45/20 Zig-zag folders B65H45/228 takes precedence

Abstract

A method of zig-zag folding and apparatus therefor wherein two endless belts are each equipped with tuckers and grippers to engage a web continuously and uniformly advanced toward the point of tucker web engagement, the paths of belt travel in the zone contacting the web to be zig-zag folded being of the order of about 60°, and wherein there is a means for providing a controlled surplus of the web spaced upstream of the point of folding, the surplus being released at the time of folding to provide precise position of the folds independent of speed.

Claims

1. Apparatus for cyclically folding a continuous web in zig-zag fashion comprising:

a frame,

web advancing means on said frame adapted to advance said web uniformly at a predetermined speed continuously along a path within said frame,

a pair of endless conveying loops mounted on said frame on opposite sides of the web path and each carrying tuckers and grippers alternately spaced thereon and arranged that a tucker of one loop cooperates with a gripper of the other loop to develop a transverse fold in said web and then a gripper of said one loop cooperates with a tucker of said other loop in developing the next transverse fold in said web wherein one cycle is completed between each successive tuckergripper engagement,

means on said frame for moving said tuckers and grippers on said loops along divergent paths from a first location where said tuckers and grippers transversely grip said web, said first location being a spaced distance from said advancing means,

means on said frame in said path and located between said advancing means and said first location for retarding said web intermittently each cycle between successive tucker-web engagements in said first location, said retarding means including a pair of retard rolls matingly engaging said web to drive it at a surface speed less than said predetermined speed to create a web surplus between said advancing means and said retarding means, a portion of the circumference of one of said rolls having a smaller radius than the remainder thereof to cyclically release said surplus at the time of tucker-web engagement in said first location.

2. The apparatus of claim 1 in which each gripper includes a pair of resilient blocks adhesively secured to its associated loop, each tucked including a T-shaped element secured to its associated loop.