Patent ID: 7850157
Filing Date: 2010-12-14
Classification: B31B,B65H

Abstract:
1. Method for the continuous or intermittent movement by friction of two bands of superimposed flexible material comprising: providing at least two pulling rollers, placed tangentially at both sides of said two bands, to pressurize the two bands as the two bands pass between the pulling rollers and thereby pull the two bands; pulling the two bands in a same direction with the pulling rollers; providing an antifriction device disposed between the two bands that allow respective movement between the two bands; adjusting the alignment of the two bands when involuntary offsets occur between the two bands by pulling one of the bands a greater distance than the other band, or pulling one of the bands in a direction opposite to the direction that the other band is being pulled, without slippage between each band and a corresponding one of pulling rollers that contacts the band; the adjusting step is performed by temporarily driving the two pulling rollers at different tangential velocities with respect to each other until the two bands are in alignment; and after the adjusting step, driving the two pulling rollers at same tangential velocities with respect to each other.