Abstract: The invention is directed to a stop device for a lift type overhead door such as may be counterbalanced by springs and cables and having guide rollers operating in guide tracks at opposite sides of the door. The stop fixture is disposed one at each side of the door and includes a pivoted door stopping dog having an operating arm extending generally parallel to a door supporting cable. The dog is positioned at one side of a track flange directly opposed to a roller at the opposite side of such flange and the dog with its operating arm are tied to this roller in a fixed dimension relationship. The operating arm is connected to a door supporting cable so that if the cable breaks the arm is immediately actuated by a spring to swing the dog into engagement with the track flange, backed up by the opposed roller at the other side of the flange, to grip the flange therebetween and thus prevent the door from falling.

Abstract: An expandable door features vertically telescoping door sections, having flexible wire guides to insure engagement of the door sections during raising and lowering operations, with a minimum of physical contact and force exerted between adjacent sections. The wire guides are uniquely shaped to assure engagement of the door sections, even when said sections become misaligned; this unique shape also allows ease of constructions and repair. The door sections may be either generally U-shaped or L-shaped, and nest one within the other when the door is opened.