GB884403A - Improved door control mechanism - Google Patents

Abstract

884,403. Door operating appliances; remotely controlled fastenings. MANGANESE BRONZE & BRASS CO. Ltd. Aug. 10, 1960 [Aug. 12, 1959], No. 27518/59. Classes 44 and 65(1). A pair of doors diagrammatically represented by chain lines are locked by pneumatically operated bolts 9 which are actuated when the doors engage projections from the control valves 8 on closing. The main reservoir 2 is connected via a pressure reducing valve 3 to a reservoir R in which the pressure is maintained nearly constant (say 70 1bs./sq. inch); the emergency valve 4, one of which is located externally on each side of the vehicle carrying the door operating system, normally connects the reservoir R with the electro-pneumatic switch 5 which when closed supplies air to the pressure reducing valve 6 whereby the double acting cylinders 1 are operated at a reduced pressure (say 25 1bs. /sq. inch) to close the doors. The valves 8, opened when the doors are fully closed are connected in series to the switch 5 at a point before the valve 6; the locks 9 are connected in parallel and are both operated when both doors are closed; also connected in parallel with the locks 9 is a device 10 which may automatically apply brakes until the doors are closed or may control a "doors closed" indicator. When switch 5 is opened the locking system is exhausted to the atmosphere, unlocking the doors, and when the pressure is low enough exhausting the cylinder 1 through the one way valve 7. Simultaneously the switch 5 supplies high pressure air (say 70 1bs./sq. inch) to the centre of the cylinder 1, through the valve 11, to open the doors. In an emergency, operation of the valve 4 exhausts the door locking system and supplies high pressure air to the centre of the cylinders 1 via the valve 11, thus unlocking and opening the doors independently of the switch 5.