Apparatus for longitudinally perforating a web of paper in a rotary printing press

An apparatus for longitudinally perforating a paper web at a folding station of a web-fed printing press, comprising:

• (a) a feed roller;
• (b) a pair of nip rollers for feeding the web into and through the folding station in coaction with the feed roller, the pair of nip rollers having rotational axes parallel to a rotational axis of the feed roller, respectively;
• (c) nip roller retractor means for moving the pair of nip rollers into and out of web-feeding engagement with the feed roller and parallel to the rotational axis of the feed roller;
• (d) a blade carrier shaft opposite the feed roller;
• (e) a longitudinally perforating blade mounted to the blade carrier shaft and disposed between the pair of nip rollers;
• (f) an anvil formed on the feed roller for engaging the longitudinally perforating blade via the web being thereby perforated, the anvil having a periphery in common with the feed roller;
• and
• (g) blade retractor means for moving the longitudinally perforating blade together with the blade carrier shaft into and out of perforating engagement with the anvil on the feed roller,
• (h) wherein the longitudinally perforating blade is movable toward and away from the feed roller independently of the pair of nip rollers, and
• (i) wherein the rotational axis of the feed roller, the rotational axes of the nip rollers, the blade carrier shaft, a contacting position between the web and the periphery common to the feed roller and the anvil, contacting positions between the nip rollers and the web and a center position of an incising portion of the longitudinally perforating blade in the web are substantially in one horizontal plane while the rotational axes of the nip rollers are disposed between the blade carrier shaft and the web when the pair of nip rollers are in contact with the web on the feed roller and the longitudinally perforating blade incises the web on the anvil.