| 摘要 |
A door system has an axis, a door attached at a first end to the axis for winding and unwinding upon the axis, and a tensioned member surrounding and partially engaging an outer layer of the door wound upon the axis. The tensioned member exerts a radial force to the outer layer of the door wound upon the axis, thereby ensuring that the door is consistently wound tightly upon the axis and permitting the fast unrolling of the door from the axis. Although the tensioned member exerts a radial force upon the door, it imparts no significant lateral forces to the door. Accordingly, the door can have a simple construction with material, cost and space savings.
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