GB2277210A - Wall mounting box for an electrical device - Google Patents

Abstract

A device (7) for interconnecting a pair of adjacent wall boxes (1) in side to side relationship to form an assembly has means (9) at each side thereof for effecting a mechanical interconnection. The device (7) includes a front-facing wall (12) which provides a surface arranged, in use, to span the space between the adjacent interconnected boxes. A composite wall box includes a pair of boxes (1) interconnected by the device (7). The front-facing wall (12) may fit flush with the surfaces of the box flanges (2). <IMAGE>

Description

WALL MOUNTING BOX FOR AN ELECTRICAL DEVICE This invention relates generally to wall mounting boxes, and particularly, but not exclusively, to those commonly referred to as dry lining boxes, useful for mounting electrical devices, such as switches and sockets, on a panel of a cavity wall or partition. A typical dry lining box has an open end adjacent which is provided peripheral outwardly projecting flange means for engagement, in use, with an outer surface of the cavity wall panel, and retaining means arranged to lie behind the inner surface of the panel, in use, to co-act with the flange means in retaining the box in position in the wall. One example of a dry lining box of this kind is illustrated in our British Patent No. 2170660.The invention is particularly concerned with means for interconnecting individual wall boxes in general, and dry lining boxes in particular, side by side to form larger composite units.

Wall boxes are usually manufactured as standard single or double items which are convenient for many applications such as mounting standard electrical switches and sockets, but there is often a requirement for the juxtaposition of several wall boxes in order to mount a group of switches and/or sockets, often of different types, to provide the required facilities.

A problem arises in mounting boxes close together in a partition wall because the formation in the wall of the necessary large mounting openings leaves a relatively flimsy wall portion between the openings which, in order to have sufficient strength to support the installed boxes, needs to be of considerable width, possibly leading to an unsightly installation, and/or requiring more space than is available for installation.

An object of the invention is to provide an improved means for interconnecting adjacent wall boxes which minimises or avoids the aforesaid problems.

According to one aspect of the present invention, a device for interconnecting adjacent wall boxes in side to side relationship such as to form an assembly including the boxes and the device, comprising means at either side thereof for effecting the interconnection, and an intended front-facing wall which provides a surface arranged so as in use to span, or substantially so, the space between the adjacent interconnected boxes.

The device preferably also has a first surface bounded at either side thereof by respective support surfaces for adjacent peripheral flange means of the adjacent boxes, in use. Typically, the first surface is arranged to lie, in use, between the adjacent peripheral flange means of the boxes, conveniently being of such height relative to the support means as to be substantially flush with the peripheral flange means in order to improve the appearance of the composite box.

Preferably, the interconnection means of the device is in the form of tongues adapted to engage in complementary slots in the arms. The device is conveniently provided with recesses for reception of the arms of the adjacent boxes projecting outwardly from respective adjacent walls of the boxes. This arrangement contributes to the lateral compactness of the composite box.

From another aspect of the invention, a composite wall box comprises a pair of outwardly flanged adjacent wall boxes connected together in side to side relationship by an interconnecting device of the invention which forms connections with parts of the adjacent boxes, a front-facing wall of the device providing a surface spanning, or substantially so, the space between the adjacent interconnected boxes.

The invention will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 is an exploded perspective view illustrating the components of one form of composite wall box of the invention; Figure 2 illustrates the components of Figure 1 in assembled condition; Figure 3 is an underneath view of the composite wall box illustrated in Figure 2, and Figure 4 is a detail in cross-section along the line 4-4 of Figure 3.

The wall boxes illustrated in the drawings are dry lining boxes similar to that described and illustrated in our British Patent No. 2170660, to which reference is directed for a detailed description thereof. Each wall box includes a hollow body 1 for the reception of an electrical device such as a switch or socket (not shown). Each body has one open end around which is provided a continuous peripheral flange 2 which limits the extent to which the body 1 may be let into a wall element of a cavity wall through an aperture formed therein for this purpose, the flange resting against the outer surface of the wall element when the body is in its installed position within the wall.Opposed side walls 3 of each body, of which only one is illustrated in each case, are provided with a system of sldts 5, through which arms 6 of retractable retention devices may be extended into engagement with the rear face of the wall element, so that they may cooperate with the flange 2 in clamping the body in place within its opening, in the manner described in our aforesaid British patent. Each arm is carried by an internally threaded boss or pillar 6A which, in use, receives a fixing screw securing an electrical accessory such as a socket, to the box in conventional manner.

The present invention is concerned with connecting together two or more wall boxes to form a composite unit for installation in a single wall opening. For this purpose, the invention provides a connecting device, designated generally by the reference 7, in the form of a generally rectangular body, the respective sides of which are recessed to provide a pair of oppositely facing cavities 8 dimensioned to receive the respective extended arms 6 therein. Each cavity contains a pair of spaced ribs 9 arranged to cooperate with notches 10 formed in opposed lateral edges of the arms 6.The intended outer face of the device 7 provides a pair of supporting surfaces 11 for engagement, in use, by the adjacent flanges 2 of the boxes 1 and, lying between the surfaces 11, a further surface 12 intended to lie between the juxtaposed flanges of a pair of interconnected boxes so as to lie substantially flush with the flanges and improve the appearance of the unit, as illustrated in Figure 2. The body also provides, between each pair of ribs 9, a further supporting surface 13 facing in a direction opposed to the surface 12, for the purpose to be described.

In order to use the connecting device 7 to connect together the boxes 1 into a composite unit, one of the arms 6 of one of the boxes is pushed outwardly through its slot system 5 so as to project from the side wall of the box. The device 7 is brought to a position adjacent that side of the box so that the projecting arm enters the cavity 8 and the device is placed with one of the support surfaces 11 underlying the adjacent flange 2 of the box. It is then possible, with the notches 10 of the arms aligned with the ribs 9, to move the arms towards the open end of the box, thereby interengaging the ribs and notches so as to lock the device and box together in a direction parallel to the plane of the box open end.The ribs 9 are tapered in thickness to a sufficient degree to lock the arm thereon at a predetermined position along the ribs, which may conveniently coincide with the arm engaging the surface 13 of the device for additional support. Coarse locking may be obtained by interengagement of the arm with saw tooth formations in part of the slot system, as described in our patent No. 2170660. The box and device 7 are thus lightly clamped together by coaction between the flange 2 and arm 6. The second box 1 may be attached to the device 7 by a similar process using one of the arms of that box, equivalent support surfaces 1 1 and 13 and ribs 9. There is thereby formed a self-contained composite box assembly ready for installation in a cavity wall.

It will be understood that each box has an arm similar to that already described associated with a system of slots in its wall opposed to that secured to the device 7. With these arms retracted, the composite unit may be inserted in an appropriate opening formed in the outer wall element of a cavity wall and rendered captive in the wall by extending the arms outwardly of the box walls so as to lie behind the internal surface of the wall element. The box may be clamped lightly in position on the wall by moving the arms inwardly towards the wall and locking them in one of the saw tooth formations, as previously.When the appropriate accessories are placed in position on the composite unit, fixing screws may be screwed into the bosses 6A, thereby drawing the arms tightly against the inner surface of the wall element to clamp the composite unit on the wall by cooperation between the appropriate part of the flange 2 and the arms. The further wall portion 12 lying between the juxtaposed flange portions 2 of the connecting device 7 in the composite unit lies flush with the outer surfaces of the flanges in order to provide a pleasing appearance to the installed unit.

If necessary, the device 7 may be provided with one or more additional tongues 15 carried by screws or similar devices 16, so that by rotation of these devices, the additional tongues may be brought behind and clamped against the interior surface of the wall element in order to provide additional support against the wall. In order to produce rotary movement of the tongues 15 sufficient to bring them into positions in which they project outwardly of the device behind the wall, the device is provided with inclined camming surfaces 15A arranged so that the act of drawing the tongues inwardly towards the wall against the camming surface rotates the tongues to their desired locking positions. The additional tongues would normally be arranged, as illustrated, at locations at the top and/or bottom of the unit where there is relatively little support.It will be seen also that the further surface 12 extends slightly outwardly of the body to match the outward projection of the flange 2 so that the space between the flanges of the installed unit is filled and further support provided for the device 7 against the wall.

It will be understood that the box illustrated is only one of a variety of similar boxes which may be interconnected by means of the device of the invention. In particular, the arms 6 may take any convenient form and may be movable between their retracted and extended positions by linear or pivotal movement or a combination of such movements. The device 7 may be modified to suit the particular form of arm employed.

Instead of providing the arms 6 with slots 10, the arms may be provided with raised portions, such as ribs, and the connecting device 7 would then be provided with complementary means, such as grooves, to receive the raised portions. The invention may be applied to wall boxes other than dry lining boxes, such as those intended to be sunk into a solid wall, for example.

It will be seen that the invention provides a simple and convenient means of connecting together two or more wall boxes into a composite unit having sufficient strength to be self-supporting when inserted into a single wall opening having no intermediate supporting plaster strips.

This gives rise to ease of installation, minimises the space required for the installation and eliminates the possibly unsightly wide strips of plaster which would otherwise be necessary between individually installed components.

Claims (18)

1. A device for interconnecting a pair of adjacent wall boxes in side to side relationship such as to form an assembly including the boxes and the device, comprising means at either side thereof for effecting the interconnection, and an intended front-facing wall which provides a surface arranged so as in use to span, or substantially so, the space between the adjacent interconnected boxes.

2. A device according to Claim 1, wherein the intended frontfacing wall comprises a first surface bounded at either side thereof by respective support surfaces for adjacent peripheral flange means of the adjacent boxes in use.

3. A device according to Claim 2, wherein the first surface is arranged to lie, in use, between the adjacent peripheral flange means of the boxes.

4. A device according to Claim 2 or Claim 3, wherein the first surface is of such height relative to the support surfaces as to be substantially flush with the peripheral flange means, in use, in order to improve the appearance of the composite box.

5. A device according to any one of the preceding claims, wherein the interconnection means thereof is in the form of tongues adapted to engage in complementary slots in the arms of the adjacent boxes projecting outwardly from respective adjacent walls of the boxes.

6. A device according to Claim 5, having recesses for reception of the projecting arms, prior to engagement of the latter with the tongues.

7. A device according to any one of the preceding claims, further comprising a tongue cooperating with screw means and arranged so that, with the device forming part of a composite wall box installed in a wall panel, operation of the screw means draws the tongue towards the device against the inner surface of the panel.

8. A device according to Claim 7, further comprising a cam surface with which the tongue cooperates, in use, so that when drawn towards the device, the tongue is caused by the cam surface to perform a rotary motion into a position in which it lies behind the inner surface of the panel.

9. A device for interconnecting adjacent wall boxes, substantially as hereinbefore described with reference to the accompanying drawings.

10. A composite wall box comprising a pair of adjacent wall boxes connected together in side to side relationship by an interconnecting device according to any one of Claims 1 to 6 which forms connections with parts of the adjacent boxes, a front-facing wall of the device providing a surface spanning or substantially so, the space between the adjacent interconnected boxes.

11. A composite wall box according to Claim 8, wherein the frontfacing wall of the device comprises a first surface bounded at either side thereof by respective support surfaces for adjacent peripheral flange means of the respective interconnected boxes.

12. A composite wall box according to Claim 9, wherein the front facing wall of the device has an intermediate portion of greater height than the remainder which lies between the supported flange portions.

13. A composite wall box according to Claim 10, wherein the intermediate wall portion is flush with the flanges to improve the appearance of the composite box.

14. A composite wall box according to any one of Claims 8 to 11, wherein the parts of adjacent boxes with which the interconnection means of the device forms the connections are respective oppositely outwardly projecting arms of the adjacent boxes.

15. A composite wall box according to Claim 12, wherein the interconnecting means of the device comprises tongues adapted to engage in complementary slots in the arms to form the assembly.

16. A composite wall box according to Claim 12 or Claim 13, wherein the outwardly projecting arms are adapted to lie behind the inner surface of a wall panel when the composite box is installed in an aperture of the panel.

17. A composite wall box according to any one of Claims 10 to 14, wherein the intermediate portion of the front facing wall of the device is approximately the same length as the adjacent box sides.

18. A composite wall box substantially as hereinbefore described with reference to the accompanying drawings.