Apparatus is provided for receiving folded cartons of non-uniform thickness from a conventional gluing device, stacking those cartons into stacks of a predefined number, and rotating successive stacks 180.degree. from each other in order to compensate for the uneven or non-uniform thickness of each folded carton. The apparatus further serves to drop two or more stacks of the folded cartons from a stack building station into a slug building area and then, once a slug of a desired size is built, tilting the slug until the plane of each folded carton is vertically oriented (i.e., the slug lies horizontally). The apparatus then automatically loads the slug into a shipping box.
An alternate package flip-over device includes an intermittently operable primary conveyor feeding batches of packages to a continuously operating secondary conveyor, and a flap for routing the batches to either a flip-over mechanism or to an intermediate transfer conveyor, the successive batches from the transfer conveyor and the mechanism rejoining on a merging conveyor, alternate batches having been flipped in the mechanism.
