GB2578427A

GB2578427A - Electrical module assembly

Info

Publication number: GB2578427A
Application number: GB1816812.0A
Authority: GB
Inventors: Mottram Christopher
Original assignee: Scolmore International Ltd
Current assignee: Scolmore International Ltd
Priority date: 2018-10-16
Filing date: 2018-10-16
Publication date: 2020-05-13
Anticipated expiration: 2038-10-16
Also published as: GB2578427B; GB201816812D0

Abstract

An electrical module 10, such as a switch or fuse module, and an assembly of a back box, front plate and said electrical module, wherein the module comprises two pairs of retention means 21, 25, a first pair comprising at least one flexible clip 26 to engage with an aperture in a yoke (70; figure 8) and a second pair comprising at least one aperture 23 for location of a retention screw (58; figure 7) whereby the module, in use, is secured to the front plate.

Description

Electrical Module and Assembly This invention relates to a module, such as a switch or fuse module, for use in an assembly comprising a back box and a front plate.

It is known to provide a yoke which is secured within a back box to provide support for a plurality of modules which each then align with respective apertures in a front plate. Typically each module is a click fit within a respective aperture. The front plate may be held in position either by being secured directly to the back box or by being secured to the yoke which in turn is secured to the back box.

Typically such yokes comprise a single row of a plurality of positions for location of a module, or may comprise a plurality of two or more such rows.

Conventionally the yokes are secured to the back box and the front plate is then secured to the yoke.

The modules typically are of an elongate rectangular shape and, especially for modules which serve as switches, the modules generally are required to be mounted in a vertical, portrait orientation.

For supporting the modules the yoke is provided at the left and right ends of the row of module receiving apertures with a first retention aperture for securing the yoke relative to a back box and a second retention aperture for securing the front plate to the yoke. Thus the fixing screws for securing the front plate are located to the left and right of the horizontally extending row of modules. That results in a pleasing appearance and corresponds with the appearance of a standard, single light switch in which an integral assembly of a switch and square front plate are secured to a back box without any requirement for a yoke.

However a problem arises if it is desired to fit to a square back box a single module of a type that is designed to be supported by a yoke. In that case it is necessary to provide a small yoke but dimensional constraints mean that the yoke cannot have said first and second retention holes positioned side by side for securing of the yoke to the back box and for securing the front plate to the yoke.

Accordingly, without significant redesigning of the yoke, it is necessary to mount the yoke in a horizontal orientation, thereby to provide a desired vertical, portrait, orientation of the module. That however, then requires provision of a bespoke apertured front plate in which the plate is provided with screw apertures at vertically orientated positions, in the vicinity of the top and bottom regions of the module aperture, for securing the front plate to the back box. However that vertical orientation of the front plate apertures is aesthetically less appealing than the aforedescribed conventional horizontal orientation. In addition to that aesthetic disadvantage the cost of providing a yoke for a single module, and provision of a front plate with specially positioned retention apertures results in the cost of the assembly of the yoke, back box and front plate being undesirable more expensive than the conventional assembly of a back box and an integrally constructed front plate and switch.

The present invention seeks to provide a module and an assembly of a module, front plate and back box in which the aforedescribed disadvantages of known modules and assemblies are mitigated or overcome.

In accordance with one aspect of the present invention an electrical module comprises two pairs of retention means, a first pair comprising at least one flexible clip to engage with an aperture in a yoke and a second pair comprising at least one aperture for location of a retention screw whereby the module may be secured to a front plate.

The invention provides also an assembly of a back box, front plate and module wherein the module comprises two pairs of retention means, a first pair comprising at least one flexible clip to engage with an aperture in a yoke and a second pair comprising at least one aperture for location of a retention screw whereby the module, in use, is secured to the front plate.

Preferably each second pair comprises two apertures each for location of a respective retention screw for securing the module to a front plate.

Preferably the first pair of retention means comprises two flexible retention clips. Preferably one clip is positioned in use of the module to be at an upper end of the module and the other at a lower end. One or each clip may be of a type which provides a click fit type location of a module within a yoke aperture.

Preferably a flexible clip comprises a latch formation which is deflectable on insertion of the module into a yoke aperture but which then reverts to a non-deflected, locking position to bear against a face of the yoke. Preferably the latch formation comprises a distal end which is accessible for deflection thereby to allow removal of the module from a yoke. Preferably, in use, the distal end is accessible at a front face of the yoke, being that face witch is intended to be covered by the front plate.

The deflectable clip may comprise at least one ear formation and preferably a pair of ear formations that extend sideways in a direction perpendicular to the direction of insertion of the module into a yoke. The ear(s) may thereby engage with part of the yoke aperture such that the module is secured against movement in the direction of the plain of the yoke.

The ear(s) may limit or inhibit movement of the module from a yoke aperture subsequent to the latch formation adopting said locking position. Accordingly sideways extending ears may be employed additionally to secure a module against that face of the module opposite that which is engaged by a distal end of the latch formation. . The second pair of retention means may comprise an abutment formation and said abutment formation may comprise an aperture, for example a non-threaded aperture, through which a retention screw may extend to engage with a screw threaded bore, preferably a blind bore, aperture in a front plate and thereby enable the module to be secured to a front plate.

Preferably the module comprises two abutment formations provided at respective ends of the elongate module. Preferably each abutment formation is provided with an aperture for receiving a retention screw.

Preferably the spacing between that face of an abutment formation which faces one face of a yoke for engagement with that face and the face of a retention clip that faces the other, opposite face of the yoke for engagement with that face is substantially equal to, and preferably no less than, the thickness of the yoke with which the module is intended to be employed.

Preferably a flexible retention clip is formed integrally with a body portion of the module. Suitable materials for forming the body portion and integral clip include materials such as nylon.

The second pair of retention means may be formed integrally with the body portion of the module.

The module may be adapted for performing any one of the well established functions of a module, such as that of a switch, a fuse housing or an indicator light.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawings in which:-Figure 1 is a perspective view of a module in accordance with present invention; Figure 2 is an enlargement of part of Figure 1; Figure 3 is a front view of the module of Figure 1; Figure 4 is a perspective view of the module of Figure 1 in a second direction; Figure 5 is a perspective view of the front of a single module in combination with a one-tier square front plate; Figure 6 is a perspective view of the module and front plate of Figure 5 from a rear position prior to completing assembly; Figure 7 is perspective view of the rear of the front plate and module when assembled together; Figure 8 is a perspective view of a yoke for supporting a plurality of modules in a single tier arrangement; Figure 9 shows a modification of the yoke of figure 8; Figure 10 is a view corresponding to that of Figure 4 and showing part of a yoke into which the module has been inserted; Figure 11 is an end view in the direction X of Figure 10; Figure 12 shows a plurality of modules, and pair of yokes and a back plate in an exploded perspective view; Figure 13 shows a completed assembly of the components of Figure 12; Figures 14a and 14b show part of Figure 13 in more detail, and Figure 15 shows the assembly of Figure 13 in combination with a front plate for attachment to the Figure 13 assembly.

A switch module 10 (see Figures 1 to 4) of elongate rectangular shape comprises a moulded body 11 provided at a rear face 12 with conventional terminals 13,14,15 for connection of electrical conductors (not shown).

The front face 16 of the body 11 comprises an integrally moulded upstanding rim 17 within which is located a rocker switch head 18.

An upper end 20 of the body 11 has formed integrally therewith two retention formations. One retention formation 21 is in the form of a tab 22 provided with a non-threaded aperture 23. The tab 22 has an abutment face 19 which in use abuts a front face of a yoke.

The other retention formation 25 is in the form of a flexible clip 26 which comprises a deflectable arm 27.

The distal end 28 of the arm is provided with first and second abutment formations 29,30.

The abutment formation 29 comprises two abutment surfaces 31 in use to engage with one face, typically a front face, of a yoke in a manner described below. The other abutment formation 30 is in the form of a pair of sideway extending ears 32 that define a pair of abutment surfaces 33 which in use engage with a second face, typically a rear face, of the yoke.

The lower end 40 of the body 11 is provided in a similar manner with corresponding retention formations 21,25.

As best seen in Figure 3, the flexible clips 26 are positioned centrally across the width of each shorter edge 41 of the module. In contrast, the tabs 22 are offset, whereby as viewed in Figure 3, one lies between a flexible clip 26 and a longer edge 42 of the module and the other lies between a flexible clip and the other longitudinal edge 43 of the module. Auxiliary tabs 49 are provided one at each end of the module and each has an abutment face to bear against a yoke to assist in locating the module in a stable manner within a yoke aperture.

Figures 4 to 6 shows use of the module with a single tier single gang type square shaped front plate 50.

The front plate 50 is provided with an aperture 51 which is dimensioned to receive the upstanding module rim 17 within which the rocker switch 18 is located.

The front plate is provided with a pair of conventional non-threaded apertures 54 symmetrically positioned to lie sideways of the longer edges 42,43 of the module, and are spaced apart in a conventional manner to correspond with the spacing of screw-threaded lugs of a standard metal or plastics back box.

Additionally the rear face 53 of the front plate is provided with two blind bore screw-threaded passages 56 at positions which align with the apertures 23 of the module. Thus a module of a selected type, such as a switch or fuse module, may readily be secured to the front plate by means of a pair of screws 58 without the need to provide a yoke or disfigure the appearance of the front panel by relocation of retention apertures 54 to be positioned in a vertical configuration, above and below the shorter edges 41 of the module.

For enabling a plurality of modules to be arranged side by side in a row, or for a plurality of rows to be arranged in a multi-tier configuration use is made of one or a plurality of yokes such as that shown in Figures 8 and 9.

Figure 8 shows a yoke 70 for use with a back box of a type conventionally embedded in a support surface and Figure 9 shows the same yoke adapted for use with a metal or plastics back box that is intended to be surface mounted. The shorter edge regions 74 of the yoke are each provided with a pair of spaced apart tabs 71 which each have regions 72 of reduced thickness whereby outer regions 73 of the tabs, as shown in Figure 7, may readily be removed thereby to enable the yoke, as shown in Figure 8, to be employed with a surface mounted back box.

The yoke shorter edge regions 74 are each provided centrally with a pair of apertures 75,76.

One aperture 75 of each pair is located further from the other end of the yoke than the other aperture 76.

The outward located aperture 75 is not threaded and is employed to receive a mounting screw which engages with a conventional screw threaded tab of the back box. The head of the screw acts as a stop to abut the yoke and limit the distance by which the yoke can freely move towards and away from the rear of the back box unless the screw has been fully engaged to bear firmly against the yoke and thus hold the yoke firmly against the back box.

The other aperture 76 of each pair is screw threaded and is positioned to be engaged by a retention screw that firmly secures a front plate to the yoke. Accordingly it will be appreciated that by adjustment of the screws that extends through the outwardly located yoke apertures 75 any irregularities in the manner in which a back box has been recessed into a support structure may be compensated to allow the front plate of an assembly to bear substantially uniformly against the outer surface of the support structure.

The longer edge regions 80 of the yoke are created by stamping of sheet metal to remove material from the centre of the yoke and they define pairs of recesses 81 which enable a module to be clipped to the yoke. Each recess comprises a central region 82 and side regions 83 over which the deflectable arm 27 of a clip 26 may be advanced whereby the abutment surfaces 33 of the clip ears bear against a rear face of the yoke. In that position the abutment surface 31 of the clip, the abutment face 19 of a module tab 22 and abutment face of an auxiliary tab bear against the front face 85 of the yoke whereby the yoke then has the modules secured thereto.

Figures 10 and 11 show a module in situ in a yoke aperture. As best seen in Figure 11 the abutment face 19 of an apertured tab 22 (and also auxiliary tab 49) is spaced from the abutment faces 30 of the ears 33 at the same end of the module by a distance substantially equal to but no less than the thickness of the yoke whereby the yoke is able to securely provide support for the module.

Figures 12 to 15 show steps in the formation on the assembly of modules in a two tier arrangement. Figure 12 shows the modules 10 ready for insertion into respective recess regions of one of the two yokes 90, and with screw threaded bolts 91 extending through the outer apertures of each yoke for engagement with respective screw threaded tabs 92 of the back box.

Figure 13 shows the arrangement of modules inserted in the yokes and with the yokes secured to the back box.

A front plate 96 (see Figure 15) is then presented to the assembly of modules 10 and secured to the yokes 90 by means of screws (not shown) extending through the front plate apertures 95 to engage with the inward screw threaded apertures 93 of the yoke.

A particular feature of the aforedescribed construction of Figures 8 to 15 is that the non-threaded apertures of the module tabs 21 may be of a robust, non-deformable construction such that the modules are firmly supported against the front face of a yoke without needing to rely on retention by means of the relatively less robust flexible clips 26. Thus it is a significant feature of the present invention that the tabs 22 are to extend from the body of a module to bear, in the assembled condition, against an outer face of the yoke.

Claims

Claims 1. An electrical module comprising two pairs of retention means, a first pair comprising at least one flexible clip to engage with an aperture in a yoke and a second pair comprising at least one aperture for location of a retention screw whereby the module may be secured to a front plate.
2. A module according to claim 1 wherein the second pair of retention means comprises two apertures each for location of a respective retention screw for securing the module to a front plate.
3. A module according to claim 1or claim 2 wherein the first pair of retention means comprises two flexible retention clips.
4. A module according to claim 3 wherein one clip is positioned in use of the module to be at an upper end of the module and the other at a lower end.
A module according to claim 3 or claim 4 wherein one or each clip is of a type which provides a click fit type location of the module within a yoke aperture.
6. A module according to any one of claims 3 to 5 wherein the flexible clip comprises a latch formation which is deflectable on insertion of the module into the yoke aperture but which then reverts to a non-deflected, locking position to bear against the face of a yoke.
7. A module according to claim 6 wherein the latch formation comprises a distal end which, in use, is accessible at a front face of a yoke for deflection thereby to allow removal of the module from a yoke.
8. A module according to any one of claims 3 to 7 wherein the flexible clip comprises at least one ear formation that extends in a sideways direction perpendicular to the direction of insertion of the module into a yoke.
9. A module according to any one of claims 3 to 8 wherein the flexible retention clip is formed integrally with a body portion of the module.
10. A module according to any one of the preceding claims wherein the second pair of retention means comprises an abutment formation comprising said aperture and through which a retention screw may extend to engage with a screw threaded bore of a front plate.
11. A module according to claim 10 wherein the abutment formation comprises an aperture which is a non-threaded aperture.
12. A module according to claim 10 or claim 11 wherein the module comprises two abutment formations provided one at each end of an elongate module.
13. A module according to claim 12 wherein each abutment formation is provided with an aperture for receiving a retention screw.
14. A module according to any one of claims 10 to 13 wherein the spacing between that face of an abutment formation which faces one face of a yoke for engagement with that face and the face of a retention clip that faces the other, opposite face of the yoke for engagement with that face is substantially equal to the thickness of the yoke with which the module is intended to be employed.
15. A module according to any one of claims 10 to 14 wherein the second pair of retention means is formed integrally with the body portion of the module.
16. An assembly of a back box, front plate and an electrical module wherein the module comprises two pairs of retention means, a first pair comprising at least one flexible clip to engage with an aperture in a yoke and a second pair comprising at least one aperture for location of a retention screw whereby the module, in use, is secured to the front plate.
17. An assembly according to claim 16 wherein the electrical module is a module in accordance with any one of claims 1 to 15.
18. An assembly according to claim 16 claim 17 wherein the spacing between that face of an abutment formation which faces one face of the yoke for engagement with that face and the face of a retention clip that faces the other, opposite face of the yoke for engagement with that face is substantially equal to the thickness of the yoke.