Patent ID: 6352257
Filing Date: 2002-03-05
Classification: B65H

Abstract:
Apparatus for controlling the movement of a sheet downstream along a flow path, toward a finishing machine which pulls the sheet downstream cyclically at high rate, with rapid change in velocity, which comprises:an assist unit comprised of one or more drive rollers, for moving sheet downstream along the flow path, having a tension ratio of less than 6 to 1; wherein, the sheet runs around said drive rollers with a total angle of wrap of less than 2 &pgr; radians; means for changing the angle of wrap, and thereby the tension ratio of the assist unit; and, a dancer unit, located downstream of the assist unit, for dynamically changing the length of the flow path responsive to changes in sheet tension; the dancer unit comprising a movable roller assembly, spring biased in a direction which maximizes the length of the flow path.