Variable-length cut-off folder and method

#1. Field of the Invention

#The present invention relates generally to web printing presses and more particularly to a folder for a web printing press as well as to a method for cutting a web and diverting the resultant signatures into two streams.

#2. Background Information

#One preferred embodiment of the present invention is described below by reference to the following drawings, in which:

#FIG. 1 shows a schematized side view of a folder according to the present invention;

#FIG. 2 shows the cutting and gripping elements of the folder of FIG. 1 in more detail;

#FIG. 1 shows a folder 100 having a first loop 101 and a second loop 102. First loop 101 has a path 105 along which run a plurality of cutting elements 3a, 3b, 3c, 3d, etc, as well as a plurality of gripping elements 4a, 4b, 4c, 4d, etc. The cutting elements and gripping elements are arranged in alternating fashion. Second loop 102 also has a plurality of cutting elements 13a, 13b, 13c, 13d, etc. and a plurality of gripping elements 14a, 14b, 14c,14d, etc, running on a path 106.

#A web 1 of material such as paper enters a gap formed between loop 101 and loop 102. “Web” as defined herein may include one or more ribbons of material, which may or may not already be longitudinally folded. Each cutting element may include a bar and a knife. Each gripper element may include a gripper and an anvil. Web 1 is thus gripped between the bar of cutting element 3b and the anvil of gripping element 14b as the cutting element 3b along path 105 and gripping element 14b along path 106 come together. The cutting elements and gripping elements can move at the same velocity as web 1 on this section of tracks 101 and 102, shown in FIG. 1 as signature formation area 1000.

#As the web moves through signature formation area 1000, it is gripped between the bar and the anvil and the knife of the cutting element cuts web 1, so as to form a plurality of signatures. For example, a knife in cutting element 13b cuts the web 1 against the anvil of gripping element 4b. Thus a signature 7 can be formed. A front edge of the signature, cut by cutting element 3c, is gripped by the gripper of gripping element 14c.