Abstract: An apparatus for forming thin paper sheets or signatures into an upright stack first arranges said sheets on a generally horizontal endless belt conveyor in a shingled stream with the leading edge of each sheet beneath the immediately preceding sheet and the trailing edge portion of each sheet projecting behind the trailing edge of said preceding sheet, and moves said conveyor continuously forwardly to bring the sheets successively into abutment with a stop so the driving force of the conveyor causes a stack to form from the bottom. The endless belt conveyor has a perforate bet, and a vacuum system below the perforate belt draws the sheets constantly and firmly downwardly against said perforate belt in a part of the path which ends at the stop, so that each sheet is conveyed positively forwardly against the stop.

Abstract: A compensating stacker for printed periodicals has lugged endless infeed means to feed periodicals forwardly seriatim in small lifts onto an upper retractable lift supporting means which opens on each cycle to drop the lifts seriatim vertically onto a lower lift supporting means which opens on each cycle to drop each lift into a stacking station. Lift rotating means turns selected lifts 180.degree. while they are supported on the lower lift supporting means, so each stack consists of a predetermined number of lifts of which some are oriented one way and some the other. Delivery means operates intermittently to move stacks seriatim out of the stacking station.

Abstract: A collator of the inserter type is especially constructed to receive a shingled stream of printed sheets from a feeding apparatus such as that of U.S. Pat. No. 3,522,943 and to afford positive feed of printed sheets from the hopper to the gatherer chain. A hopper which holds a vertical stack of printed sheets is provided with stack control means which includes lifter hooks operated through a box cam mechanism.