Paper web threading apparatus for rotary printing presses

Abstract

A plurality of drive elements, such as electric motors supplied with sprockets, are located along a threading path for the paper web of a rotary printing press; a threading element, such as a sprocket chain of a finite length somewhat longer than the maximum space between drive elements is moved along the path, for example, in a guide channel, the threading element cooperating with switches located adjacent the drive elements to energize the drive element adjacent a leading edge of the threading element, and move the threading element along to the next threading element, the trailing end turning the switch OFF since drive power will be supplied by the next drive element along the path. This sprocket chain carries a gripper with which the leading edge of the paper web to be threaded into the printing press can be gripped. The channels guiding the sprocket chain preferably are flexible, for example, plastic, and may be formed with switches so as to short-circuit certain guides of the drive elements, either in the forward threading, or in a return idling path.

Dependencies are inferred from the claim text.