Patent GB-1384862-A (GB)
Title: Fire door structure and fire safety installation including said door structure
IPC: E06B5/16
Filed: 1973-02-20
Abstract: 1384862 Fire doors J P C LACOMBE 20 Feb 1973 [22 Feb 1972 9 Feb 1973] 8368/73 Heading A5A A fire door which is resiliently biassed towards the closed position is formed with an opening closed by a movable flap; locking means normally secure the flap to the door but release it in the event of fire, and first and second resiliently yieldable means bias the flap to the closed and open positions respectively, the second means over-riding the first but being rendered inoperative at a given elevated temperature by fusible means to permit flap closure by the first means. In a modification the force of gravity acts instead of the first resiliently yieldable means.  Fig. 2 shows the lower part of a fire door according to the invention, the main door 21 being constructed of core 23 and facings 24, and mounted in frame 18 which is doubly recessed at 19 and sealed with asbestos 20. The door is hinged at 22 and biassed towards closing by a known resiliently yieldable device (not shown). At the foot of 21, opening 25 is normally closed by flap 26 which is pivoted on hinges 27, 28 each co-operating with resiliently yieldable means. Hinge 27 is conventional and has a torsion spring (not shown) tending to close the flap. Hinge 28 is illustrated in Figs. 6, 7 and exerts an opening force greaterthan that of hinge 27. Flap 26 comprises core 29 and facings 29A and is secured to door 21 by locking mechanism 30. In Figs. 3, 4, 5, this comprises a locking member which, in the event of fire, can be withdrawn manually by pulling a rod (Figs. 3, 4) or pushing a button (Fig. 5), or automatically by an electromagnet (Figs. 3-5). Hinge 28 comprises knuckles 74, 75 respectively connected to frame 18 and flap 26, and spring 86 attached to 74 by rotatable cup 84 formed with apertures 85 which can be aligned with apertures 82 in 74. Spring 86 is adjusted to exert the required force by rotation of cup 84 and then retained rigid with respect to knuckle 74 by insertion of fusible pins 89. In Figs. 8A-C a modified door is shown in which the flap is of the guillotine type operated by a cable and pulley, and in Fig. 9 the flap is a Venetian shutter. Fig. 1 shows the fire door structures 17 as an integral part of a fire protection system in building B. If fire breaks out at level N 1 , detector 7 is actuated, energizing electromagnets 16 and thus. opening flaps 26. People in areas PH escape by passing through corridor CO, through chamber S by opening doors 17, and thence to stairway E. The fact that flaps 26 are open ensures that there is no pressure differential on each side of chamber S hindering the opening of doors 17. Detector 7 also actuates generator 1 which starts fans 2, 4 to evacuate smoke through duct 5 via openings 25 of the fire doors. Fire-fighting means may be inserted through these openings. When fire spreads to chamber S and fusible pins 89 of hinges 28 melt, flaps 26 are closed by the action of hinges 27 and level N, is isolated from other building levels. If detector 7 fails to energise electromagnet 16 the means interlocking door 21 and flap 26 is broken manually, as indicated in relation to Figs. 3-5.