GB251297A - Improvements in or relating to driving gear for paper rolls of rotary printing machines - Google Patents

Abstract

251,297. Maschinenfabrik Augsburg- N³rnberg, Akt.-Ges. April 27, 1925, [Convention date]. Feeding webs.-In a web-feeding mechanism for rotary printing-machines in which the web roll is automatically traversed along a spindle, by means of a device operated by the rotation of the roll as it is unwound, so as to keep the roll in contact with a feeding-belt, means are provided for keeping the pressure of the roll on the belt substantially constant irrespective of the thickness of the web. The roll spindle c is provided with a worm d engaging a worm wheel e formed as a nut engaging a screwed spindle f so that as the roll is rotated it is raised to keep it in contact with a feeding-belt b mounted on rollers h, i. The roller i is mounted between springs l, m, and its movements are adapted to actuate switches r, o controlling a reversible motor p geared to the spindle f. The parts are arranged so that with normal pressure of the roll on the belt, both switches are open and the motor at rest. If a web thinner than normal is being fed, the pressure on the belt increases so that the roller i is pulled down against the action of the spring l and the switch o is closed. The motor p is thus driven in a direction to lower the roll until the rise of the roller i again opens the switch o. If a thick web is being fed, the pressure on the belt decreases and the spring l raises the roller i so that the switch r is closed. The motor p is thus driven to raise the roller until by the increased pressure on the belt the roller is again drawn down and the switch r opened. Magnets may be employed instead of springs m, l.