Patent ID: 7757437

Claim:
A door for at least partially covering a doorway and movable relative thereto, the doorway being defined by a surrounding structure that includes a wall such that the doorway has a width, the door comprising: an upper track; a door panel suspended from the upper track and being movable horizontally relative to the doorway along a predetermined normal path; a lower track disposed below the upper track, wherein the lower track is attachable to the surrounding structure such that the lower track is entirely outside the width of the doorway; a panel retention system comprising: a track follower movably coupled to the lower track; and a housing mounted on the door panel along a longitudinal side of the door panel and in which a biasing element is positioned, wherein the biasing element is operatively coupled to the track follower and has a longitudinal axis that is substantially parallel to the longitudinal side of the door panel, wherein an interaction between the biasing element and the track follower at least partially guides the door panel along the predetermined normal path, wherein the biasing element limits movement of the door panel out of the predetermined normal path, wherein if the door panel moves out of the predetermined normal path, the track follower remains in contact with the lower track and the biasing element is extended.