GB1411155A - Ceiling-mounted apparatus for providing a smoke vent or smokeproof screen in the event of a fire - Google Patents

Abstract

1411155 Smoke vent or smokeproof screen RIKEN LIGHTMETAL INDUSTRY CO LTD 10 April 1973 [10 April 1972 6 June 1972 8 June 1972 13 June 1972] 17105/73 Heading A5A A smoke vent or a smokeproof screen comprises (i) a frame mounted on a ceiling defining a rectangular opening therethrough and having horizontally extending guide grooves on its opposing inner surfaces. (ii) a lid normally closing the opening. (iii) means supporting the lid at one end thereof and including a plurality of guide portions slidably received in the guide grooves of the frame, (iv) lock means normally retaining the lid closed, and (v) at least one pivotable arm connecting the lid and frame such that when the lock means is actuated to unlock the lid the latter opens under gravity, its free end moving substantially vertically downward as the guide portions of the support means slide along their respective guide grooves. Frame 1 as illustrated is formed of identical joined steel members 1a-1d but alternatively may be integrally moulded. Each member 1a-1d comprises a hollow, substantially rectangular-sectioned part 7 including inner and outer walls 5a, 5b, horizontally extending upper flange 8, and lower flange 9 supporting the edge of the ceiling. Inner wall 5a is recessed at 6 to define a guide groove extending horizontally round 1a-1d. Frame 1 is mounted with flange 9 in engagement on the ceiling by means of support member 12 fixed to joists 11; fixture 13 attached to each of 1a-1d is coupled to bolt 14 via pin 15, and 14 is screwed to 12. For use as a smoke vent duct 18 is coupled to flange 8 of frame 1. However if lid 20 is to act as a smokeproof screen the open upper end of 1 is closed by sheet 21. Lid 20 (Fig 5) openably closing the lower end of frame 1 is constructed with frame 22 of similar size and shape to frame 1, and panel 23 supported by 22 so as to be flush with ceiling 17. Frame 22 includes upper portion 24 composed of hollow rectangular sectioned members 24a-24d joined at 26, and lower portion 25 of U-shaped members 25d-25d screwed to 24 at 30, one of 25a-25d being screwed to 24 only after panel 23 has been inserted. Resilient blocks 32, or alternatively washers, can be inserted to space corresponding members of 24, 25, (Fig 5C) and hence adjust the dimensions of 25 to the required gap G between itself and frame 1. The lid 20 is supported within frame 1 by pair of rods 34 along one end thereof, each being formed with portion 35 of smaller diameter than guide portion 36 at the outer end of 35. Part 35 is both slidably and rotatably received in sleeve 37 fixed to the same end of lid 20, guide 36 being received in guide groove 6 in frame 1. Springs 38 urge the rods against grooves 6 and adjusting screws 39 regulate the friction therebetween. A pair of arms 40 on opposite ends of lid 20 pivotally extend between support 41 on frame 1 and support 43 on 20 by means of pins 42 and 44 respectively. Lock means 45 on the inside of frame 1 normally engages latch 46 on lid 20 and is electrically connected to a smoke detector for actuation thereby. When lock 45 is released by the smoke detector lid 20 moves under gravity, turning downwardly on rods 34 at the same time as being pulled forwardly by arms 40 as guides 36 of rods 34 slide in grooves 6, as shown in Fig 6, until reaching the open vertical position to the extreme left of Fig 6. Thus the size of spacings G can be minimised. In Figs 7-11 an alternative embodiment is shown in which lid 20 is of sufficient size to act as a smokeproof screen and different support means are required.