GB2393846A

GB2393846A - Housing for a sounder assembly

Info

Publication number: GB2393846A
Application number: GB0223079A
Authority: GB
Inventors: Alan Capaldi-Tallon; Diego Madronero Melo
Original assignee: Apollo Fire Detectors Ltd
Current assignee: Apollo Fire Detectors Ltd
Priority date: 2002-10-04
Filing date: 2002-10-04
Publication date: 2004-04-07
Also published as: GB0223079D0

Abstract

A housing 10 for a sounder assembly adapted for mounting to a ceiling or wall, comprises a region 16 disposed centrally of the periphery of the housing, and a plurality of acoustic horns 34 angularly distributed around said region to conduct sound emitted by the sounder outwardly from the base. A more even polar response can be achieved, and apertures 52 may be provided between the horns for wiring to pass to a detector mounted on the sounder assembly.

Description

Housing for a sounder assembly This invention relates to a housing for a

sounder assembly incorporating an audible sounder ea. for fire or evacuation or intruder alarm systems.

In modern fire alarm systems, there is an increasing tendency for detectors and alarm sounders to share the same wiring. This is especially true of analogue addressable systems where detectors and sounders are connected to the same loop wiring. The loop wiring in this case provides both communication and power to the devices.

Since there may be many tens of sounders connected to one loop of an analogue addressable system it is important that the current demanded by each sounder is as small as possible. It is also important, for aesthetic reasons, that the sounders should be unobtrusive when installed. This implies that they should have the lowest possible profile.

In addition to stand-alone sounders, there is now demand for sounders that are integral with detectors. This demands even lower profile since the combined detector/sounder must be as low as possible. There is also a requirement to allow access from the rear of the detector/sounder combination for field wiring.

In a known sounder assembly GB 2322727A a sounder is mounted off-centre in its housing. Whilst this provides a central aperture through which wiring to a detector can be routed, the polar sound emission characteristic of the device is asymmetric, with the result that the basic alarm function of the device is compromised.

The present invention, at least in its preferred embodiments, seeks to avoid these disadvantages. In one aspect the invention provides a housing for a sounder assembly adapted for mounting to a ceiling or wall, comprising a region disposed centrally of the housing and configured to receive a sounder, the housing comprising a plurality of generally diverging passages angularly distributed around the region to conduct sound emitted by the sounder

outwardly from the housing.

Preferably the passages are shaped as acoustic horns.

The passages may extend to the periphery of the housing.

There may be at leas! three passages equally angularly spaced apart.

The housing may comprise a mounting surface for mounting the housing to a ceiling or wall, the passages being inclined relative to the mounting surface for at least part of their length. The mounting surface may be on a base portion of the housing, the housing also comprising a sounderreceiving portion which together with the base portion defines the passages. Preferably walls defining the passages diverge primarily in the direction of the angular distribution of the passages.

The housing may be configured to have mounted thereon a hazardous condition detector.

By 'hazardous condition detector' we mean a detector responsive to fire, smoke, noxious gas, radiation, intruders or other conditions which may present a threat to a person or property in the space guarded by the detector.

An aperture may be provided between two said acoustic horns for the passage of wiring to the detector.

The invention also provides a sounder assembly comprising a housing as set forth above, and a sounder disposed in said region of the housing.

In a second aspect the invention provides a housing for a sounder assembly adapted for mounting to a ceiling or wall, comprising a region disposed centrally of the housing and

configured to receive a sounder, the housing comprising a plurality of passages angularly distributed about the region to conduct sound emitted by the sounder outwardly from the housing, the housing being configured to have mounted thereon a hazardous condition detector and having, in a space between two adjacent said passages, an aperture to permit wiring to pass through the housing to the detector or a connector for connecting the detector to wiring in the housing Further, the invention provides a detector and sounder assembly comprising a housing as set forth above, a hazardous condition detector, and a sounder disposed in said region of the housing.

The invention now will be described merely by way of example with reference to the accompanying drawings wherein: Figure I is a perspective view, partially in section, of a sounder assembly according to the invention, and Figure 2 is a perspective sectional view of part of the assembly of figure 1.

Referring to figure 1, a sounder assembly comprises a housing 10 having a generally disc-

shaped base portion 12 and an annular sounder-receiving portion 14 having a region 16 bounded by a cylindrical wall 18 which receives a sounder 20. The sounder is of a conventional piezo-electric type, having a recess 22 from which a loud alarm sound issues when the sounder is operated.

Figure 2 shows the base portion 12 together with some of the parts of the sounder-

receiving portion 14, which are shown shaded. In use, the base portion 12 is installed on a wall or ceiling, with its rear surface 24 disposed towards the wall or ceiling. The base portion includes keyhole slots for two screws to mount to the wall or ceiling. The two parts 12, 14 of the housing are joined by the hot staking or ultrasonic welding of small bosses or tabs (not shown) formed on the underside of portion 14 (ea. on walls 32, discussed below) which pass through corresponding openings in portion 12 and are staked

or welded on the underside thereof. Bosses 28 of base portion 12 received in apertures 26 formed in the sounder-receiving portion 14 assist accurate registration of the portions 12, 14 before they are joined together. Bosses 28 also accept, in holes 30, screws to fix the base (not shown) of a hazardous condition detector which fits concentrically on to the .. sounder-recevmg portion.

The sounder receiving portion 14 has three walls 32 which together define three equally angularly-spaced generally-diverging channels or passages 34 radiating from the centre of the base portion 12 to its periperhery. When the sounder-receiving portion 14 is assembled to the base portion, in the orientation shown in the drawings (i.e. upside down compared to when the assembly is attached to the ceiling) base portion provides a rear surface or floor 38 for the channels, which as hereafter described are preferably shaped to form acoustic horns for directing the sound from the sounder out of the housing 10.

The radially inner portions of the channels are of constant crosssectional area. At approximately its mid-point 36, each channel begins to diverge angularly about the polar axis 50 of the base portion 12. Also at this point the bottom surface 38 of base portion 12 is inclined away from the rear surface 24 of the base portion. The surface of the portion 14 is similarly inclined at 40 with the result that the channel is inclined away from the rear surface 24. At the outermost region 42 of each channel, the inclination thereof away from the rear surface 24 ceases so that the channel has a cranked or sinuous shape. By shaping the channels in this way, it is possible to position the sounder closer to the rear surface 24, whilst still achieving efficient sound emission. The height of the assembly, and thus its visual intrusion, thereby is reduced. The channel terminates in a mouth 44 defined by the outer edge 46 of the portion 14 and a rounded lip 48 on the base portion 12. Together, these features cooperate to direct the emitted sound downwards away from the ceiling.

The increase of the cross-sectional area (height x width) of each channel 34 along its length follows conventional rules for acoustic horns, as known to those versed in the art of designing loudspeakers. The three equally-spaced acoustic horns each have directional but overlapping polar emission characteristics about the polar axis 50 of the sounder assembly. As a result the overall emission characteristic of the sounder is relatively

constant in azimuth. Whilst it is preferable that the channels 34 are shaped as acoustic horns, adequate if less than optimum acoustic performance may be obtained if the channels are just of generallydiverging form or indeed do not diverge at all.

An aperture 52 is provided in the base portion 12 within the included angle defined by each wall 32, through which wiring can be passed to the hazardous condition detector (ea.

a smoke, carbon monoxide, or intruder detector) mounted on the sounder housing 10. The wiring may terminate at connectors ea. 54 on the housing 14, with which the detector engages when fitted to the sounder assembly, or it may pass through corresponding apertures in the housing portion 14 and terminate in a suitable wander connector for connection to the detector. Thus the provision of wiring to a detector is achieved without the need to dispose the sounder 20 asymmetrically in the housing 10.

Each feature disclosed in this specification (which term includes the claims) and/or shown

in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features.

Statements in this specification of the "objects of the invention" relate to preferred

embodiments of the invention, but not necessarily to all embodiments of the invention falling within the claims. Reference numerals appearing in the claims are illustrative only and the claims shall be interpreted as if they are not present.

The description of the invention with reference to the drawings is by way of example only.

The text of the abstract filed herewith is repeated here as part of the specification.

s

Claims

1. A housing for a sounder assembly adapted for mounting to a ceiling or wall, comprising a region disposed centrally of the housing and configured to receive a sounder, the housing comprising a plurality of generally diverging passages angularly distributed around the region to conduct sound emitted by the sounder outwardly from the housing.

2. A housing as claimed in claim 1 wherein said passages are acoustic horns.

3. A housing as claimed in claim 1 or claim 2 wherein the passages extend to the periphery of the housing.

4. A housing as claimed in any preceding claim wherein there are at least three passages equally angularly spaced apart.

5. A housing as claimed in any preceding claim comprises a mounting surface for mounting the housing to a ceiling or wall, the passages being inclined relative to the mounting surface for at least part of their length.

6. A housing as claimed in claim 5 wherein the mounting surface is on a base portion of the housing, the housing also comprising a sounderreceiving portion which together with the base portion defines the passages.

7. A housing as claimed in any preceding claim wherein walls defining the passages diverge primarily in the direction of the angular distribution of the passages.

8. A housing as claimed in any preceding claim configured to have mounted thereon a hazardous condition detector.

9. A housing as claimed in claim 8 comprising an aperture between two said passages for the passage of wiring to the detector, or a connector for connecting the detector

to wiring in the housing.

10. A housing for a sounder assembly adapted for mounting to a ceiling or wall, -I comprising a region disposed centrally of the housing and configured to receive a sounder, the housing comprising a plurality of passages angularly distributed about the region to conduct sound emitted by the sounder outwardly from the housing, the housing being configured to have mounted thereon a hazardous condition detector and having, in a space between two adjacent said passages, an aperture to permit wiring to pass through the housing to the detector, or a connector for connecting the detector to wiring in the housing.

I 1. A sounder assembly comprising a housing as claimed in any preceding claim, and a sounder disposed in said region of the housing.

12. A detector and sounder assembly comprising a housing as claimed in any of claims 1 to 10, a hazardous condition detector, and a sounder disposed in said region of the housing.

13. A housing or an assembly substantially as herein described with reference to the accompanying drawings.