Platform conveyor

Another form of the conventional poternoster (See definition for Poternoster) is the platform conveyor that consists of multiple, equally spaced battens which form rigid horizontal surfaces in one direction (up and down) but behave like the front of a roll top desk on the return. Platform conveyor is an effective means of moving a continuous flow of pallets or other unit loads between levels.
Another variation of the posternoster concept, which permits both vertical and horizontal movement of load, consists of freely swinging platforms suspended between two parallel chains.