The disclosure relates to a conveyor for unfolding a flat, folded rigid or semi-rigid container blank into a container. The conveyor includes two opposing lugged chain conveyor assemblies which are separated at a sufficient distance at the entry end to receive and engage a folded blank between opposed notches in the two lugged chain conveyor assemblies. As the folded blank progresses in the machine direction, the two opposing lugged chain conveyor assemblies become closer to each other so as to unfold the blank into a container with a storage volume therewithin.