METHOD AND APPARATUS FOR FEEDING A BAND OF OVERLAPPED BLANKS TO A SEPARATOR

摘要

In an envelope making machine a band of overlapped blanks is conveyed from an adhesive drier to a blank separator by a refeeder. The refeeder has pairs of inner and outer endless belts that are driven at the same speed with the outer belts overlying portions of the inner belts. The belts engage the band of overlapped blanks therebetween and convey the band from the drier to the separator. is positioned beneath an idler roll carriage that has an end release roll adjacent the separator. The separator includes pull-out rollers with a radially extending pull-out segment on one roller that engages the front or leading edge of the blank and accelerates the front blank to separate it from the band of overlapped blanks and feed it in timed relation to the subsequent elements of the envelope forming apparatus. When the length of the blank changes or when the dimension of the conveyors in the drier and refeeder increase with increased operating temperatures of the machine, an adjustment is required in the phasing or timing of the blanks delivered to the separator so that the pull-out segment continues to engage the front leading edge of the blank. The disclosed refeeder adjusts the timing of the blanks by changing the effective length of the refeeder conveyor and thus the distance that the band of overlapped blanks travels from the drier to the separator. The length of the refeeder conveyor is changed by moving two reference frames or drums relative to each other. Movement of one reference drum changes the effective length of the path followed by the blanks and movement of the other reference drum changes the effective length of the inner belts. The outer belts have spring loaded take-up idlers that proportionately adjust the effective length of the outer belts to conform to that of the inner belts. An endless chain drive mechanism for the inner and outer belts is connected to the pair of reference drums so that the effective length of the chain is adjusted with the reference drums. The pitch diameter of the belt drive pulleys and belt drive sprockets is substantially the same so that the chain velocity remains constant and the phase relation of the chain drive changes with the endless belts.