GB975617A - Improvements in or relating to door arrangements - Google Patents

Abstract

975,617. Door-operating appliances. A. TROUVAIN. May 15, 1963, No. 19343/63. Heading E2M. Two hinged doors, particularly for use in a mine, are interconnected so that when one door is opened it pulls the other open also, the arrangement being such that the doors move at substantially the same angular velocity as they start to open but at the end of the opening movement the one door has undergone a greater angular displacement than the other. The doors 1, 2 may be hinged to a central door post 3 and are interconnected by a cable 5 passing around a pulley 4, the angle through which the pulled door opens being dependent on the relative positions of the pulley, the hinge axes and the points at which the cable is secured to the doors. In the fully open position (Fig. 4) the air current flowing in the direction of the arrow 6 exerts a greater force on the pulled door 2 than on the door 1 so that both doors begin to close, complete closure of the doors being effected by a relatively weak spring or a small counterweight. Alternatively the closing may be assisted by mounting the doors on inclined axes or by providing inclined surfaces to lift the doors slightly as they open. Two cables may be employed one on each side of the doorway. The doors may be of unequal size.