Smoke or fire barrier

Abstract

The present invention relates to a smoke or fire barrier for closing an opening in a building, the barrier including: a curtain for closing the opening; means arrangeable at a head of the opening for deploying the curtain and for retracting the curtain; guide means at sides of the opening for retaining edges of the curtain after deployment and for reducing flow of smoke past the edges of the curtain, the guide means including: a pair of jaws for holding the edges of the deployed curtain, at least one of the jaws being movable towards the other and means for moving the or each movable jaw after deployment of the curtain.

Claims

1. A smoke or fire barrier for closing an opening in a building, the barrier including: a pleated or concertina curtain for closing the opening; means arrangeable at a head of the opening for deploying the curtain and for retracting the curtain; guide means at sides of the opening for retaining pleated or concertina edges of the curtain after deployment and for reducing flow of smoke past the pleated or concertina edges of the curtain, the guide means including: a pair of jaws for holding the pleated or concertina edges of the deployed curtain, at least one of the jaws being movable towards the other; the pair of jaws being spaced apart before deployment to allow passage of the pleated or concertina edges of the curtain therebetween, and means for moving the or each movable jaw after deployment of the curtain, the pair of jaws adapted to close openings or gaps created by a pleated or concertina edge through which smoke can pass doors for covering the guide means when not in use, and to be urged open when in use; and wherein the door is held in an open position with the provision of at least one spring and a closed position with the provision of at least one electromagnet, the electromagnet force being stronger than the spring bias to hold the doors in the closed position.

2. The smoke or fire barrier as claimed in claim 1, wherein the jaws are plates arranged parallel to each other.

3. The smoke or fire barrier as claimed in claim 1, wherein the jaws of the pair are movable towards each other.

4. The smoke or fire barrier as claimed in claim 1, wherein the jaws are linked together to provide translational movement of one or both jaws or are hinged together to provide pivotal movement of one jaw or both jaws with respect to the other.

5. The smoke or fire barrier as claimed in claim 1, further comprising a switch connected to the means for moving the or each jaw to activate movement of the or each jaw to retain the curtain.

6. The smoke or fire barrier as claimed in claim 5, wherein the switch is provided at the bottom of the guide means.

7. The smoke or fire barrier as claimed in claim 1, wherein the doors are pivotally connected to the guide means.

8. The smoke or fire barrier as claimed in claim 1, further comprising a retraction switch adapted to cause the means for moving the or each jaw to move at least one of the jaws away from the other, releasing the curtain.

9. The smoke or fire barrier as claimed in claim 1, further comprising a retraction switch adapted to switch on the electromagnets.

Description

(1) To help understanding of the invention, a specific embodiment thereof will now be described by way of example and with reference to the accompanying drawings, in which:

(2) FIG. 1 is a front view of a smoke or fire barrier according to the invention;

(3) FIG. 2 is a cross-sectional view through the barrier of FIG. 1;

(4) FIG. 3 is a front view of an edge channel according to the invention, with the edge plates open;

(5) FIG. 4 is a front view of the edge channel of FIG. 3, with the edge plates closed;

(6) FIG. 5 is a front view of the edge channel having a door in the closed position; and

(7) FIG. 6 is a front view of the edge channel of FIG. 5, with the door open.

(8) Referring to the drawings, the smoke or fire barrier 1 comprises a curtain 2 contained in a headbox 4 mounted at the top of an opening 6 in a wall or the like in a building. The curtain is stored pleated. The curtain is also provided with a bottom bar 8, to weigh the curtain for descent. A number of wires 10 are provided attached to loops 12 at the ends of the pleats 14 and to the bottom bar 8. The wires are attached to spindles 15, which rotate under power to control the deployment and retraction of the curtain.

(9) In accordance with the invention, along each edge 16 of the opening 6 is provided a side guide 17. As shown it is provided in a channel 22 in the edge of the opening, the channel having two sides 23 and a back 25. Alternatively the side guide 17 as such could be mounted on the edge 16 of the opening. The side guide 16 includes a pair of edge plates 18, 20 for clamping the curtain after deployment. The plates are long strips, typically of metal, in particular steel, although they could be of high temperature resistant plastics materials. The plates form the sides of an open channel 28 into which the edge of the curtain passes on deployment.

(10) The edge plates are connected together at their inner edges by diagonal cross members 24. One of the edge plates 18 is secured to the channel 28, while the other one 20 is connected to the first via the cross-members 24. The movable plate 20 is connected to a motor, which when switched on urges the second plate into a position flat against the first plate. When the curtain is deployed this will clamp the curtain between the first and second plates, which will prevent removal of the curtain from the guide, for example as a result of a fire draft, and also prevent the passage of smoke around the edges of the curtain.

(11) When the curtain is withdrawn and held in within the headbox, the channel is open, with the edge plates arranged on either side of the channel 28. On activation of an alarm condition, the curtain is deployed, with the edges of the bottom bar 8 and the curtain 2 passing down the channel. When the bottom bar reaches the floor, or bottom extent of its deployment, it triggers a switch, typically by depressing a plunger, which activates the motor to urge the movable plate 20 against the fixed plate 18, clamping the curtain therebetween. The edge plates close in the manner of a trellis, with the movable plate 20 moving across with respect to the fixed plate 18. However, other movement actions can be envisaged, for example the edge plate could slide directly across the channel on runners. This prevents, or significantly reduces, smoke from passing around the edge of the curtain.

(12) To withdraw the curtain a user has to press a switch 26. This may be after a test or a false alarm. Pressing of the switch causes the motor to open the edge plates to release the curtain. It also causes the curtain motor to withdraw the curtain by rolling the wires on the spindles.

(13) Conveniently, the channel 28 may be provided with a door 30, which can close the channel when the curtain is fully withdrawn, concealing the channel. The door 30 is hingedly 31 connected to the fixed plate 18 and when the curtain is fully withdrawn can be closed. The door is held in an open position by a spring 32, or a series of springs along the length of the door. However, the door can also be held closed by a series of electromagnets 34. These may be provided at intervals along the length of the door, or a single magnetic may be provided. The magnets are stronger than the spring, such that while the electromagnets are switched on the door remains closed. On activation of an alarm condition, power to the electromagnets is switched off, causing the door to open under action of the spring(s) 32. The curtain can then descend with its edge passing down the channel 28.

(14) As discussed above, for withdrawal of the curtain, a user presses a withdrawal switch. In additional to opening the edge plates and withdrawing the curtain, this switch also turns the electromagnets back on. Once the curtain has been fully withdrawn the user can then manually close the door, which will be held in place by the electromagnets.

(15) Thus, in the event of an alarm signal the power to the electromagnets 34 is switched off, which results in opening of the door, and opening the channel. The curtain can then descend. Usually this will be as a result of release of a brake, allowing the weight of the curtain and bottom bar to cause the curtain to fall. However, the descent may be powered. Once the curtain reached the bottom of the channel, it activates a switch which closes the edge plates 18, 20, clamping the edges of the curtain between them.

(16) For withdrawal of the curtain, a user pressed a withdrawal switch, which initially opens the edge plates 18, 20. In addition, the curtain motor is activated with withdraw the curtain, but drawing the wires up onto the spindle. On full withdrawal of the curtain, the brake is then activated to hold the curtain in the withdrawn position. The power to the electromagnets 34 is also turned on. Once the curtain has been withdrawn, the door 30 over the channel 28 can be closed by a user, concealing the channel.

(17) The invention is not intended to be restricted to the details of the above-described embodiment. For instance, while the side plates are described with reference to a pleated or concertina curtain, they could also be used with a curtain provided on a roller, or in any other way. In a further alternative, the jaws are not plates but at least one edge which clamps the curtain either against the side of a channel forming the side guide, or two edges clamping the curtain therebetween. In some embodiments the jaws may be provided with soft flexible edges for improved contact with the jaw and the curtain to further minimise smoke passing around the edge of the curtain.