Pod door alignment device

Abstract

A system is disclosed for ensuring a properly aligned position of a pod door within the opening in a pod shell upon location of the pod at a tool load port. The door positioning assembly according to the present invention includes a cam affixed to rotating latch hubs of a pod door latching assembly, and a cam follower mounted around each of the cams, which followers include arm portions that extend out toward an edge of the pod door. When the pod door and shell are separated, the arm portions are held in a retracted position completely contained within the footprint of the pod door. However, upon rejoining the pod door to the pod shell, mechanisms in the port door rotate the latch hub cams. Cam rotation causes translation of the arm portions of the cam followers so that the ends of the arm portions extend out beyond an edge of the pod door and against a surface of the pod shell. In their extended positions, the arm portions maintain a desired vertical positioning of the pod door within the pod shell opening. Moreover, as the arm portions remain in their extended positions after the pod door is coupled to the pod, the positioning assemblies prevent the door from sagging downward in the pod shell opening as a result of its own weight or as a result of a shock or jolt to the pod.