Abstract: A door comprises two flexible door panels or sections wound on tubes on opposite sides of a door frame. Uprights at the free edges of the door sections are supported and driven in opposite directions by toothed belts driven by a driving shaft extending through one of the winding tubes, the other tube having a similar shaft driven in the opposite direction by a reversing mechanism, the tube of each flexible door section being connected to its shaft by a spring barrel maintaining the door section under tension.