GB2604032A

GB2604032A - Electrical installation component

Info

Publication number: GB2604032A
Application number: GB2200439.4A
Authority: GB
Inventors: Chris Mottram
Original assignee: Scolmore International Ltd
Current assignee: Scolmore International Ltd
Priority date: 2021-01-14
Filing date: 2022-01-14
Publication date: 2022-08-24
Also published as: GB202100452D0

Abstract

A converter box 30, for use with a back box 45, comprising four side walls 31-34 and a rear wall 35 which together define a cavity. The rear wall has a rear face which comprises at least one protrusion extending in an opposite direction to the side walls, with the protrusion being intended to locate within the cavity of the back box. The rear wall also comprises at least one aperture 39, through which retention means may act to secure the converter box to a support surface surrounding the back box. Preferably, the rear wall comprises an opening and a recess region which extends around the opening. The protrusion may be positioned between the opening and at least a part of the recess. There may be four protrusions in the form of ribs for locating within each corner of a rectangular back box. The converter box may be for conversion of a single gang back box.

Description

Electrical Installation Component This invention relates to an electrical installation component and in particular, but not exclusively, to a converter box for use with a so-called back box for the mounting of an accessory such as a power socket or light switch. The invention relates also to the combination of a converter box and a back box.

It is well known to provide a back box converter whereby a back box of a one gang size may be extended by having secured thereto a converter box that is of a two gang or greater size.

Typically, a back box, whether of the recessed or surface mounted type, comprises a pair of screw threaded mounting lugs which enable the front plate of an accessory such as a light switch or power socket to be secured to the back box.

Those screw threaded mounting lugs also may be employed to provide a most convenient facility for securing in position a converter box whereby a back box of one gang size may be extended to a two gang size. Similarly a two gang back box may be extended to a three gang size. However, it is necessary to ensure that the converter box is of sufficient strength in the region of apertures provided for retention screws that enable the converter box to be secured to the screw threaded lugs of a smaller size back box.

Although back boxes for locating in a recess typically are made of metal, known converter boxes typically are made of plastics material for aesthetic reasons and for conforming more closely to the shape of a conventional multi-gang front plate. To provide a converter box made of metal and having a profile that corresponds closely to that of a conventional front plate would be relatively expensive.

The problem of ensuring that a plastics converter box is of sufficient strength in the region of apertures for retention screws has hitherto been addressed either by providing the plastics converter box with a metal insert as shown in Figure 1 or ensuring that the rear face of the converter box is moulded to have locally thicker plastics regions (see Figure 2) of a sufficient strength for withstanding a force such as that which arises when a plug is withdrawn from a socket secured to the front of the converter box.

In more detail, Figure 1 shows a moulded plastics back box 10 having a rear wall 11 provided with a rectangular aperture 12 for allowing access to a back box and for passage of cables into a converter box. The opening 12 is surrounded by a metal frame 13 provided with two apertures 14 for retention screws that extend through the apertures to engage with the conventional screw threaded lugs of a back box.

The back box 20 of Figure 2 similarly is formed with an opening 21 in the rear wall 22. The rear wall is formed with integrally moulded stiffening ribs 23 and each stiffening rib is provided with an aperture 24 for a retention screw which, in use of the converter box 20, engages with a respective one of the pair of screw threaded lugs of a back box.

Although the provision of a metal insert or a relatively thickened and enlarged plastics region facilitates the provision of a converter box of plastics material and of an adequate strength, the provision of a metal insert adds significantly to the cost of the product, and the provision of thickened regions of moulded plastics material at the rear wall of the converter box undesirably restrict the space within the converter box for routing of electrical cables and for accommodating accessories such as switches and sockets.

The present invention seeks to provide an improved converter box for a back box wherein the disadvantages of hitherto known converter boxes are mitigated or overcome.

In accordance with one aspect of the present invention there is provided a converter box for a back box, said converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from a front face of the rear wall thereby to define a cavity for housing at least pad of an electrical accessory, the rear wall having a rear face comprising at least one location protrusion extending in a direction opposite the direction in which the side walls extend from the rear wall, said at least one protrusion being provided in use to locate within the cavity defined by a back box and said rear wall additionally comprising at least one attachment aperture position whereby in use retention means may extend through an aperture in the rear wall to attach the converter box to a support surface surrounding the back box, said rear wall defining an access opening in use to lie over a back box and the rear wall further defining a recess region which extends around said access opening, said at least one location protrusion being positioned between said opening and at least a part of the recess.

The invention is particularly applicable to use of the converter box with a back box of a type in accordance with British Standard BS 4662:2006+A1:2009.

The invention is particularly applicable to a converter box formed of moulded plastics material.

In another aspect the invention provides an assembly comprising the combination of a back box for recess mounting and a converter box, the converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from the periphery of a front face of the rear wall thereby to define a cavity for housing at least part of an electrical accessory, said rear wall having a rear face comprising at least one location protrusion which extends in a direction opposite the direction in which the side walls extend from the rear wall, said at least one location protrusion being provided in use to locate within the cavity defined by the back box, and wherein the rear wall comprises at least one attachment aperture which is located at a part of the rear wall which does not directly overlie the back box.

Thus the at least one location protrusion readily facilitates correct location of the converter box relative to a back box whilst the converter is being attached to a support surface by means of retainers extending through attachment aperture(s) at the aperture position(s) of the converter box.

In a further aspect the invention provides a method of adapting a recessed back box by the use of a converter box, said method comprising providing a converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from the periphery of a front face of the rear wall thereby to define a cavity for housing at least part of an electrical accessory, said rear wall having a rear face comprising at least one location protrusion which extends in a direction opposite the direction in which the side walls extend from the rear wall, said at least one location protrusion being provided in use to locate within the cavity defined by the back box, and wherein the rear wall comprises at least one attachment aperture which is located at a part of the rear wall which does not directly overlie the back box, the method comprising employing the at least one location protrusion to locate the converter box relative to the back box and then employing at least one retainer to extend through the rear wall at one of the attachment aperture positions and securing the retainer to a support surface surrounding the back box thereby to secure the converter box to the support surface.

Accordingly it will be understood that the converter box does not require a facility for direct attachment to the back box.

An attachment aperture position may be an opening pre-formed in the rear wall. Alternatively or additionally there may be provided at least one attachment aperture position which is in the form of a localised region of the rear wall which is readily ruptured to create an opening for insertion of a retainer. A rupturable localised region may be of material which is relatively thin compared with adjacent regions of the rear wall.

At least one side wall and or the rear wall of the converter may be provided with a screw threaded aperture for use for securing to the converter box an electrical accessory such as a two or more gang switch or two or more gang electrical socket.

The rear face of the rear wall may comprise four location protrusions each in the form of a locating rib for locating within a respective corner region of a rectangular shaped back box.

The rear wall may comprise an access opening which is bounded at least in part by at least one said location protrusion. At least in the vicinity of a location protrusion said access opening in the rear wall may be of a dimension less than that of the opening in the front face of a back box into which the at least one protrusion extends. The or each location protrusion may be positioned adjacent the boundary of the access opening in the rear wall. The access opening may be a pre-formed opening or may be a position at which the rear wall may be readily ruptured to create an opening.

The access opening may be of a dimension equal to or greater than that of a back box in the or each region of the rear wall that is not occupied by a said protrusion.

The rear face of the converter box may comprise a single location protrusion which extends continuously around an access opening position in the rear wall At least one location protrusion extending from the rear face of the rear wall may define at least one abutment surface which is a close fit against a side wall of a back box of standard dimensions, for example a close fit within corner regions of a rectangular back box of standard dimensions as set out in the aforementioned British Standard. Alternatively the at least one protrusion may define at least one abutment surface which may reside slightly spaced from a side wall of a said back box when in the assembled position thereby allowing for slight angular adjustment of the positioning of the converter box, about an axis perpendicular to the plane of the rear wall. Preferably the angle of freedom of the converter box is at least 2 degrees and, especially in the case of use with a single gang back box preferably is at least at least 3.5 degrees. Preferably the maximum angle of freedom is no more than 10 degrees From the foregoing it will be understood that the at least one location protrusion from the rear face of the rear wall is not required to provide a structural interconnection between the converter and a back box. Accordingly optionally the at least one protrusion may be moulded integrally with the rear wall but be readily removable therefrom. Thus with the at least one or each protrusion removed from the rear face of the rear wall the converter box may alternatively readily be used as a conventional surface mounted back box for a multi gang electrical accessory. For that purpose one of the side walls of the converter may be provided with a knock out region for entry of a surface mounted cable.

As in respect of the converter box aspect of the invention, the rear face of the rear wall of the converter box of the method and assembly aspects of the invention similarly may comprise a region which is recessed relative to parts of the rear face that, in use, contact the support surface to which the converter box is to be secured. Said recess region may have a profile, for example rectangular or circular, corresponding to the profile of the front face edges of the side walls of a conventional back box whereby if the converter box is secured to a back box that protrudes slightly from a wall cavity, the protruding regions of the back box may be accommodated at least in part within the recess region. Preferably the recess region permits a degree of the aforementioned angular movement which is substantially equal to that permitted by the location formation(s).

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:-Figure 3 is a perspective view of an assembly of a converter box of the present invention and a metal back box; Figure 4 is a rear view of the converter box of Figure 3; Figure 5 is a rear view of the assembly of Figure 3 with the rear wall of the back box removed for purposes of illustration; Figure 6 is a perspective view showing the rear face of a converter box in accordance with a second embodiment of the present invention; Figure 7 is a perspective view of pad of a conventional back box mounted in manner in which it protrudes slightly from a wall cavity, and Figure 8 is a cross sectional view, in a plane perpendicular to the rear wall of the converter box when positioned over the back box of Figure 7.

In Figures 3 to 5 there is shown a converter box for conversion of a single gang back box 30 which is of a type in accordance with British Standard BS 4662:2006+A1 2009.

The converter box 30 is of moulded plastics construction and comprises four side walls 31 -34 and a rear wall 35 to define a cavity region 36 for location of electrical accessories such as switches or sockets mounted at the rear of a front plate that may be secured in position to cover the cavity.

The box 30 is of a rectangular shape having two opposite side walls 32, 24 that each support a formation 37 provided in conventional manner with a screw threaded insert 38 for receiving a retention screw by means of which a front plate may be secured to the converter box.

At each corner position of rear wall there is provided a attachment aperture position 39 of plastics material which is relatively thin compared with that of adjacent plastics material of the rear wall whereby in use at least some of the aperture positions may be ruptured readily for receiving retention screws by means of which the converter box may be secured to a support surface surrounding a recessed back box 45. The aperture positions adjacent the end wall 34 are spaced from the aperture positions 32 at the other end 32 by a distance greater than 90mm,thereby to be spaced apart further than the 75mm width of the single gang box.

The rear wall 30 is formed with an access opening 40 of a size substantially equal to the front of the recessed back box 45. Adjacent each of the four corners of the opening 40 the rear face 41 of the rear wall 36 is provided with an integrally moulded location protrusion 42 (see Figure 4) that in the assembled condition with a back box extends part way into the back box as best seen by the view of Figure 5.

Each of the location protrusions 42 defines an abutment surface 43 that faces away from the opening 40 and which in use may abut the internal face of a side wall of the back box 35. However, a spacing of abutment surfaces that face in opposite directions may be less than the spacing of opposite side walls of the back box whereby, in use, any misalignment of the back box from a preferred orientation, e.g. a horizontal orientation, advantageously may be accommodated by movement of the converter box relative to the back box whilst the protrusions nevertheless assist in correct general location of the converter box at the time of securing the converter box to a support surface by means of retention screws extending through one or more of the corner attachment aperture positions 39.

Although the converter box of Figures 3 to 5 is intended to be used for the purpose of converting a single gang back box thereby to provide a two gang facility, the converter box may alternatively be used as a conventional surface mounted two gang back box by the simple expedient of removing the protrusions 42. Because the protrusions 42 are required merely to assist in location of the converter box relative to a back box, and are not required to provide a structural interconnection between the two boxes, they may be of a construction which enables them relatively readily to be removed to permit direct surface mounting without a back box being present. Accordingly, for that purpose the converter box of the present invention may be provided with side walls 33, 35 which have conventional knock out positions 46, 47 as shown in Figure 4.

Referring to Figures 6 to 8 there is shown a converter box in accordance with a second embodiment of the invention. The converter box 50 is constructed substantially similarly to that of the first embodiment of the present invention and the rear face 51 has a peripheral region 52 which in use is intended to contact and rest against a support surface to which the box is secured. Additionally the rear face comprises two cross portions 53 in relatively close proximity to the access opening 40 and similarly to contact and rest against a support surface to which the box is secured.

This embodiment differs from that of the first embodiment in that the cross members 52 and the peripheral regions 52 are spaced from the opening 40 by a recess 55 that extends around the opening 40, outwards of the projections 42, thereby to provide a channel region within which the protruding portion Of any) of a recess mounted back box may extend. Accordingly, not withstanding that a back box 45 might have edge regions 59 that protrude from the surface 60 of a wall cavity, the provision of the recess 55 will typically enable the mounting surfaces 52, 53 of the rear of the converter box to be mounted in a manner in which they may uniformly bear against a flat mounting surface.

In relation to the first embodiment it has been described that the abutment surfaces of the location protrusions 42 that face in opposite directions may have a spacing less than the spacing of opposite side walls of the back box whereby, in use, any misalignment of the back box from a preferred orientation, e.g. a horizontal orientation, advantageously may be accommodated by movement of the converter box relative to the back box. To facilitate that movement for a converter box of a type such as that of the second embodiment and comprising a recess region, the recess has a width greater than the thickness of the back box side walls thereby to facilitate that degree of freedom and facilitate adjustment of position.

As also in respect of the first embodiment, regions 57 of the rear wall lying between the projections 42 may be relieved thereby to provide a larger opening for positioning over the back box.

Having regard to the foregoing it is to be understood that the present invention provides a converter which does not require provision of a metal insert for strength purposes. Additionally it does not require the provision of thickened plastics regions at the front face of the rear wall for retainers that conventionally locate a converter to screw threaded lugs of the back box.

Claims

Claims.1. A converter box for a back box, said converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from a front face of the rear wall thereby to define a cavity for housing at least part of an electrical accessory, the rear wall having a rear face comprising at least one location protrusion extending in a direction opposite the direction in which the side walls extend from the rear wall, said at least one protrusion being provided in use to locate within the cavity defined by a back box and said rear wall additionally comprising at least one attachment aperture position whereby in use retention means may extend through an aperture in the rear wall to attach the converter box to a support surface surrounding the back box, said rear wall defining an access opening position in use to lie over a back box and the rear wall further defining a recess region which extends around said access opening, said at least one location protrusion being positioned between said opening and at least a part of the recess.
2. A converter box according to any one of the preceding claims wherein the access opening position is bounded at least in part by at least one said protrusion.
3. A converter box according to claim 1 or claim 2 wherein at least in the vicinity of a protrusion said access opening in the rear wall is of a dimension less than that of the opening position in the front face of a back box into which the at least one protrusion is adapted to extend.
4. A converter box according to any one of the preceding claims wherein the access opening position is of a dimension equal to or greater than that of a back box in the or each region of the access opening that is not occupied by a said protrusion.
5. A converter box according to any one of the preceding claims wherein the or each protrusion is positioned adjacent the boundary of the access opening position in the rear wall.
6. A converter box according to any one of the preceding claims wherein the rear wall is pre-formed with an opening at said access opening position.
7. A converter box according to any one of the preceding claims wherein the access opening position is a position at which the material of the rear wall is rupturable to create an opening.
8. A converter box according to any one of the preceding claims wherein said at least one protrusion defines at least one abutment surface which, in use, is a close fit against a side wall of a back box of standard dimensions.
9. A converter box according to any one of claims 1 to 8 wherein said at least one protrusion defines at least one abutment surface which may reside spaced from a side wall of a back box of standard dimensions thereby allowing adjustment of the position of the converter box relative to the back box.
10. A converter box according claim 9 wherein the spacing of said at least one abutment surface from a side wall of a back box of standard dimensions is sufficient to permit rotation of the converter box relative to the back box though an angle of at least 2 degrees as considered about an axis perpendicular to the plane of the rear wall of the converter box
11. A converter box according to any one of the preceding claims wherein the rear face of the rear wall comprises four protrusions each in the form of a locating rib for locating within a corner region of a rectangular shaped back box.
12. A converter box according to any one of the preceding claims wherein said at least one protrusion is integral with the rear wall but is removable therefrom.
13. A converter box according to any one of the preceding claims wherein at least one of the side walls of the converter box is provided with a rupturable region for use as a cable entry.
14. A converter box according to any one of the preceding claims wherein the recess region of the rear wall has a profile corresponding substantially to the profile of the front face edges of the side walls of a back box of standard dimensions.
15. A converter box according to any one of the preceding claims wherein the converter box is adapted for use with a standard back box which is in accordance with British Standard BS 4662:2006+A1:2009.
16. An assembly comprising the combination of a back box for recess mounting and a converter box, the converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from the periphery of a front face of the rear wall thereby to define a cavity for housing at least part of an electrical accessory, said rear wall having a rear face comprising at least one location protrusion which extends in a direction opposite the direction in which the side walls extend from the rear wall, said at least one location protrusion being provided in use to locate within the cavity defined by the back box, and wherein the rear wall comprises at least one attachment aperture which is located at a part of the rear wall which does not directly overlie the back box.
17. An assembly according to any one of the preceding claims wherein the converter box is a converter box according to any one claimsl to 15.
18. A method of adapting a recessed back box by the use of a converter box, said method comprising providing a converter box comprising a rear wall and four side walls which extend from the periphery of the rear wall, said side walls extending in a first direction from the periphery of a front face of the rear wall thereby to define a cavity for housing at least part of an electrical accessory, said rear wall having a rear face comprising at least one location protrusion which extends in a direction opposite the direction in which the side walls extend from the rear wall, said at least one location protrusion being provided in use to locate within the cavity defined by the back box, and wherein the rear wall comprises at least one attachment aperture which is located at a part of the rear wall which does not directly overlie the back box, the method comprising employing the at least one location protrusion to locate the converter box relative to the back box and then employing at least one retainer to extend through the rear wall at one of the attachment aperture positions and securing the retainer to a support surface surrounding the back box thereby to secure the converter box to the support surface.
19. A method according to claim 18 and comprising the use of a converter box according to any one of claims 1 to 15.