Patent ID: 9434572
Filing Date: 2016-09-06
CPC Classification: B65H

Claim Text:
1. A method for reducing feed rate variations in a web material when unwinding a parent roll about a longitudinal axis to transport the web material away from the parent roll at a web takeoff point, the method comprising the steps of: dividing the parent roll into a plurality of angular sectors disposed about the longitudinal axis; using an ideal speed reference signal, SRS correlating each of the sectors at the web takeoff point with a corresponding one of the sectors at the drive point; determining a rotational speed for each of the sectors, while at the drive point, as the parent roll is being driven; calculating a drive point radius for each of the sectors by calculating the radius at the drive point for each of the sectors from the driving speed and the rotational speed using the formula: calculating an ideal drive point radius by adding the drive point radii for all of the sectors to determine a sum and dividing the sum by the total number of sectors; calculating a drive point correction factor for each of the sectors as a function of the drive point radius and the ideal drive point radius using the formula: calculating a modified drive point correction factor for each of the sectors using the formula: measuring a web takeoff point radius for each of the sectors by measuring the radius at or near the web takeoff point of the parent roll for each of the sectors as the parent roll is being driven at the drive point; calculating an ideal web takeoff point radius by adding the web takeoff point radii for all of the sectors to determine a sum and dividing the sum by the total number of sectors; calculating a web takeoff point correction factor for each of the sectors as a function of the web takeoff point radius and the ideal web takeoff point radius using the formula: calculating a modified total correction factor for each of the sectors as a function of the modified drive point correction factor and the web takeoff point correction factor using the formula: multiplying the modified total correction factor, C adjusting the driving speed, M