Abstract: A mechanism for moving one or more first load supporting hangers through a predetermined path that is defined by the interior of a hollow longitudinally slotted first frame. Each hanger is rotatably supported from a first ball that is movably supported within the first frame. The interior of the first frame not filled with first balls is filled with second balls. A first wheel that has pairs of spaced lobes on the circumference thereof projects through an opening in the first frame, with the pairs of lobes sequentially engaging the balls when the first wheels is rotated. The first and second balls and the hangers supported from the first balls are moved longitudinally in the first frame as such sequential engagement of the balls takes place. Should it be desired to move a platform having first and second ends through said predetermined path, the first end is connected to the first hanger, and the second end to a second hanger.