Importance

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Abstract

Paperboard sheets are fed by a feeder including driven wheels which engage the lowermost sheet of a stack and drive it through the nip rolls of a box-finishing machine is synchronism with the latter. Supporting the sheets is a grate movable between a raised position wherein the wheels are spaced from the sheet and a lowered position wherein the lowermost sheet engages the wheels and is fed thereby to the nip rolls. Below the grate is a vacuum box for holding the sheet on the wheels. Raising and lowering of the grate is effected by a cam which may be adjusted to vary the feed stroke in accordance with the length of the sheets. For driving the wheels there is provided a dual input drive mechanism including a constant velocity input drive and a variable input drive which are resolved at a single output drive to the wheels. The output drive varies in velocity such that when the wheels initially engage the sheet, the wheels are at nearly zero or absolute zero velocity and subsequently the wheels reach a constant velocity for driving the sheet at said constant velocity which is matched with the surface velocity of the nip rolls. In an alternative embodiment, the feeder may be adjusted to feed either a single sheet or a plurality of sheets per cycle of the associated box-finishing machine.

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First Claim