Abstract

A continuous running web with panels in zig-zag formation is delivered by a conveyor in the form of a scalloped stream and successive panels are deflected into a duct wherein the panels descend and gather on a bottom wall between two upright sidewalls which contact alternate fold lines between the panels of the growing stack. When the stack on the bottom wall, which descends at the rate at which the stack thereon grows, contains a predetermined number of panels, a spreading device is caused to enter between the topmost panel of the fully grown stack on the bottom wall and the panel above such stack to establish a gap for entry of the dull leading edge of a reciprocable flat tool which moves across the duct in a horizontal plane and breaks the fold line which is then located in the path of movement of the leading edge. The sidewalls have confronting vertical surfaces which are inclined relative to the leading edge of the tool. Such leading edge can be formed by a small-diameter roller which is mounted on a plate-like portion of the tool and is driven so that it rolls along the panel above it while the tool moves across the duct.