Safeguard against cable break for overhead doors which engages the round rail side

摘要

The invention relates to a braking mechanism for overhead doors which in the event of a cable break prevents uncontrolled closure of the door leaf by means of a chisel penetrating the round side of the door-runner rail. On doors already fitted it is not necessary to adapt the rail construction or the door leaf. The safeguard against cable break consists of a baseplate on which a hinged clip is mounted. The hinge pin (gudgeon) is also the space in which the bottom runner is fitted. By means of a twin auxiliary torsion bar (torsion spring), clip plus chisel are forced against the door- runner rail in the event of a cable break or a slack cable. The weight of the door will cause the chisel to penetrate the rail. The hinge point (pivot) is positioned between the panel and the chisel and has a play of 7.5 mm between chisel and round section of the door-runner rail. The safeguard against cable break is effective even in the bend of the rail. In the event of a cable break, the remaining cable produces no friction.