Overhead transportation system for transporting objects between multiple work stations

Proposed is an overhead transportation system for transporting FOUPs in the environment of semiconductor production. The system includes a pair of rails and a hoist travelling along the rails on two pairs of independently controlled wheels. The wheels are driven from in-wheel drive motors and are provided with lateral guide rollers that prevent the wheels from contact with the side walls of the rails. The FOUP gripper mechanism for grasping FOUPs is suspended from the hoist on multifunctional electrically conductive straps, which raise a gripper-grasped FOUP by pulling it up together with the lower pulleys of the strap-guiding unit. The gripper mechanism is attached to a swinging member rotationally installed on a slider, which is laterally moveable from the hoist toward a work station. The in-wheel motors receive power from batteries on the hoist. Other drives are fed from an external source switched in to the hoist on work stations.