GB2058551A - Bracket - Google Patents

Abstract

A bracket for mounting a transducer casing on a wall in the vicinity of a junction box fed via conduit, comprises:- a rectangular shelf 4 with an upturned lip 5 along its outer edge; and a pair of spaced vertical sheet metal arms 6 projecting upwardly from the inner edge of the shelf 4 and have keying portions 7 displaced forwardly at their upper ends; the arms being passed between the conduit and the wall, one on either side of the junction box with the junction box just above the shelf, and the unit being fixed in position by screws passing through holes 15 in the arms 6. The casing of the transducer is designed to form a precise fit with the bracket, with the shelf 4 forming the bottom of the casing. The device may be mounted upside down (ie with the shelf above the junction box) if required. <IMAGE>

Description

SPECIFICATION Fixing patrice In view of recently amended building evacuation requirements it is necessary, in many situations, to replace existing alarm bells by speech transducers.

Appropriate transducers are available and take the form of a compact, high-efficiency, pressure-type loudspeaker enclosed in a rectangular metal casing.

Such a transducer can be connected directly to the existing wiring, i.e. that previously used for supplying the bell, but practical problems arise in the substitution. The wiring is most commonly enclosed in conduit which terminates in a metal junction box and these together obstruct the fitting of a transducer, since it is desirable to fit this in at least approximately the same position as the previous bell in order to cover the scarring of the wall resulting from the removal of the bell.

According to the present invention, a fitting for this purpose is in the form of a patrice comprising a rectangular shelf of sheet metal formed with an upturned lip along its outer edge and having projecting perpendicularly upwardly from zit a pair of spaced, sheet metal arms, conveniently formed from the same sheet as the shelf, and having keying portions at their free ends which are displaced forwardly from the plane of the arms. When fitting in position, the arms are passed between the conduit and the wall, one on either side of the junction box, and the unit is slid upwardly until the shelf is situated just below the junction box with the two arms spaced at least approximately symmetrically one either side of the box. The unit is then fixed to the wall in this position by means of screws passing through fixing holes in the arms.It will be appreciated that since the arms are of sheet metal, there is no difficulty in passing them between the conduit and the wall and the fact that they are spaced apart allows space for the junction box so that neither the conduit nor the junction box itself obstructs the fixing operation.

The casing of the transducer is designed to form a precise fit with the patrice, the shelf forming the lower side of the casing, which is ithermise open at this side. This casing of the transducer is also of sheet metal, the front side overlapping the upturned lip of the shelf so that fixing screws can be inserted thrugh mating holes in the front of the transducer and the lip itself. The top of the transducer casing has two slit-like openings through which the keying portions at the free ends of the two arms are fitted.

The transducer is moved into position from above and then lowered until the key portions project through their openings and the casing is supported by the she If where it is secured in position by the fixing screws just mentioned. The casing of the transducer is also open over the side facing the wall and is designed to have free space to accommodate the junction box. As a consequence, the transducer fits snugly against the wall, covering any scarring resulting from the removal of the previous bell and the oniy additional requirement is that there should be an opening at one or both ends of the transducer casing for the passage of the conduit. For this purpose, the casing may conveniently be formed with one or more portions which can be removed to accommodate the passage of the conduits.

Although, for convenience of description, the arms have been referred to as extending upwardly from the shelf, it is equally possible for the unit to be fixed in an inverted position, in which case, of course, the arms extend downwardly and the shelf no longer extends beneath the transducer casing, but forms its top, with the weight of the transducer being taken by the fixing screws passing through the lip on the shelf. An inverted position such as this may be necessary, for example, if the conduit is close to a ceiling or other projection from the wall so that it is impossible to fit the transducer from above. By inverting the patrice unit as just described, the transducer may be fitted from below, all the movements previously described being inverted.

As mentioned originally, the wiring to alarm bells is most commonly enclosed in conduit, but mineralinsulated cable is also used and a similar problem arises in that the presence of the cable obstructs the fitting of the transducer in a position where it will cover the scarring of the wall. A patrice unit in accordance with the invention although designed primarily for use in conjunction with conduit is also equally applicable for use in conjunction with mineralinsulated cables. In this case, there is no junction box to be accommodated and instead, a terminal block may be fitted to the patrice, e.g. on one of the arms, to which both the lines from the transducer unit may be connected.

When used in this alternative manner, the unit can be fitted either with the shelf at the bottom as originally described or in the inverted position and, depending on the lay-out of the cable and the presence of other obstructions, the cable may be led to the interior of the unit in a number of different ways.

In particular, it may be passed through openings either in the ends of the transducer casing or in the shelf, these openings being provided as previously described by the provision of portions which can be removed as required.

Examples of a construction in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the patrice in its normal or upright position; Figure 2 is a perspective view of a transducer for fitting to the patrice of Figure 1; Figure 3 is a diagrammatic, sectional end view showing the transducer of Figure 2 fitted to the patrice of Figure 1; Figures 1A, 2A and 3A are views corresponding to Figures 1, 2 and 3 respectively with the components in the inverted position; Figures 1 B, 2B and 3B are views corresponding to Figures 1, 2 and 3 showing the patrice fixed in position in relation to conduit and a metal junction box; The drawing(s) originally filed wasiwere informal and the print here reproduced is taken from a later filed formal copy.

and Figures 1 C, 2C and 3C are further corresponding views showing the patrice fixed in its inverted posi tion forthe reception of mineral-insulated cable.

Figure 1 illustrates the basic configuration of pat rice unit which is fabricated from metal sheet and comprises a rectangular metal shelf4 formed with an upturned lip 5 along its outer edge and having a pair of upwardly projecting arms 6 extending from I its inner edge. The free end of each arm 6 is formed with a keying portion 7 and the arms are inter connected at 8 for purposes of strength. As best seen from the sectional view of Figure 3, each keying por tion 7 is slightly cranked so as to be displaced for wardly from the plane of the arms, thus being dis placed from a wall 10 to which the unit may be fixed so as to fit into a corresponding slit-like opening 12 in the upper surface of a transducer indicated gener ally as 14 in Figure 2 designed to fit the patrice of Figure 1.Each arm 6 is formed with a fixing hole 15 and the right hand arm 6 is provided with a terminal block 16 for use with mineral-insulated cable. The shelf 4 is formed with a number of stamped knock out portions 17 also for use with mineral-insulated cable.

Figures 1 A, 2A and 3A show the same features in their inverted position and it can be seen that the transducer 14 is open at what is the top in Figure 2A (and bottom in Figure 2), this side being closed, when assembled, by the shelf 4. The ends 18 of the transducer element 14 are formed with grilles 19 for the passage of speech from a loudspeaker unit, part of which is seen at 20 in Figure 2A. The front face 21 of the transducer 14 is formed with screw holes 22 for the reception of fixing screws which extend into mating holes 23 in the lip 5. These screws are shown diagrammatically in an exploded position at24 in Figures 3 and 3A and are of the tamper-prooftype.

Figure 1 B shows the patrice of Figure 1 fixed to a wall carrying conduit 26 extending from a junction box 27. The arms 6 have been passed between the conduit 26 and the wall, the conduit being forced slightly away from the wall if necessary, for this pur pose. The junction box is accommodated in the space between the arms 6 and the unit is fixed to the wall by means of screws 28, thus being ready for the reception of the transducer 14. This is fitted in posi tion from above, so that the keying portions 7 pass throughtheiropenings 12 and is lowered until it rests on the shelf 4 with the screw holes 22 in line with the holes 23 in the lip 5. The screws 24 are then screwed home and locked to hold the transducer firmly in position.The same series of steps is involved when the patrice is in the inverted position of Figure 1 A, the difference being that the transducer is suspended from the shelf 4, its weight being taken by the screws 24. The conduit 26 needs to pass through the ends of the transducer 14 and, as seen in Figure 2B, the metal casing of the transducer is formed at the ends with a number of plastic insert portions 30, the appropriate one of which can be knocked out to accommodate the conduit 26.

Figure 1 C shows the patrice fixed in the inverted position for use in conjunction with mineral insulated cable 32. It is assumed that this cable is fitted close to a ceiling or other projection from the wall so that the transducer 14 has to be fitted from below. It will be seen that two of the knock-out portions 17 have been knocked out forthe passage of the cables 32 and the individual conductors from the cable, two of which are shown as 33 are connected to the terminal block 16. Corresponding conducto rs from the transducer 14 are connected to the other side of the block 16 to complete the electrical connections. When a junction box 27 is present, the connections from the transducer 14 are made directly to the junction box and the electrical termination block 16 is not used.

Claims (7)

1. A patrice for mounting a transducer on a wall and comprising a rectangular shelf of sheet metal formed with an upturned lip along its outer edge and having projecting perpendicularly upwardly from its inner edge a pair of spaced sheet metal arms having keying portions at their free ends which are displaced forwardly from the plane of the arms.

2. A patrice according to claim 1 in which the upwardly projecting arms are integral with the shelf.

3. A patrice according to claim 1 or claim 2 in which the arms and the lip are formed with fixing holes.

4. A patrice according to any one of the preceding claims in which the shelf is formed with removable portions to provide holes forthe passage of mineral-insulated cable.

5. The combination of a patrice according to any one of the preceding claims and a transducer having a casing which forms a close fit with the shelf and an open back so that the keying portions on the arms can pass through complementary slits in the top of the casing to assist in holding the transducer in position.

6. A combination according to claim 5 including a patrice according to claim 3, in which the front of the casing of the transducer overlaps the lip of the shelf and is formed with fixing holes in register with those in the lip.

7. A combination according to claim 5 or claim 6 in which the casing of the transducer is formed with removable portions to provide holes for the passage of mineral-insulated cable.