GB2275833A - Wall box - Google Patents

Abstract

A wall box, generally made of sheet metal, has a base (10) and four upstanding side walls (11). The box has an open front which is closable by a removable cover fastened to the box, for example by screws. A shield (530) shields any electrical conductors in the box from contact with, and potential damage by, the fastening means. The shield (530) may be formed from a piece of sheet metal deflected to form front, top and side panels 531, 522, 532, 533 respectively. Side panels 532 and 533 are also deflected to provide wings 532' and 533' respectively. Lugs 526 may be stamped out of side wall 11 to engage the wings 532' and 533', and a lug 553 is stamped from base 10 to engage front panel 531 of the shield 530. A shield may be separate from a screw-retainer of the box (figs. 1 to 3, figs. 4 to 6 not shown). Other embodiments disclose different shapes of shields and different organisations of shield, box and screw-retainer. <IMAGE>

Description

WALL BOX The present invention relates to sheet metal boxes generally referred to as wall boxes, which are used in electrical installations.

Such wall boxes comprise a base, side walls and an open front. The boxes are for mounting on a wall including a ceiling or floor to contain either a switch, socket, junction, or other electrical apparatus. Such electrical components generally also provide a cover for the box.

A cover is secured to the box by fastening means such as screws, which are typically received in apertured tongues which extend inwardly from the box walls.

Generally at least two securing tongues are provided on a box, usually on opposing side walls. Often one of the tongues is incorporated into a slidably mounted bracket adjacent the inner surface of one of the box walls. This is to allow for adjustment of the cover or electrical component relative to the box to compensate for any misalignment of the box on installation so that the cover may be presented in a desired position. GB Patent Nos.

887371, 915097, 1051900 and 1126090 are examples of such wall boxes.

A problem associated with the prior art metal wall boxes is that there is a risk that, on installation when an electrician is securing the cover or component to the box, the securing screws may engage and damage an electrical conductor within the box. This may cause an electrical short circuit when the power is turned on.

The electrician then has the laborious task of removing the covers, typically from a number of boxes, to find and rectify the problem. In addition, a D.I.Y. person loosening a cover plate when decorating risks damaging a conductor, which can be expensive and even dangerous.

Some plastic wall boxes may be moulded to include screw pillars having threaded inserts for receiving screws to ensure the cover is tightly secured to the box.

We have found that the pillars may also reduce likelihood of the screws contacting the electrical conductors.

Sheet metal boxes however, pose a much greater hazard than plastic boxes, particularly if the box is surface mounted i.e. not recessed into a wall below plaster level. It is noted that metal boxes are intended for both surface and flush mounting.

The present invention seeks to alleviate at least some of the aforementioned problems. With this in mind, the present invention seeks to provide in particular a metal box, of the general type mentioned above, and of new or improved construction which may inhibit the cover retaining screws from coming into contact with electrical conductors within the box.

Accordingly, with this object in mind, in a broad aspect the present invention provides a wall box, typically made of metal, for accommodating one or more electrical conductors, the box comprising a base, side walls extending generally upwardly from the periphery of the base to define an open front for the box which is closable by a removable cover and fastening means for securing the cover to the box, means being provided in the box and associated therewith for shielding the conductor against damage by the fastening means as/when the cover is secured to the box.

Another aspect of the invention concerns provision of such shield means.

In this context the term electrical conductor includes electrical wiring having an insulative protective sleeve.

Suitably the shield means are provided at least at or near the base of the box. In this way the shield means can help prevent the conductor becoming trapped between the fastening means and the base of the box. It will be appreciated that if pressure is applied to the conductor by the fastening means, it is possible to damage the conductor, for example to penetrate the protective insulating sleeve on a conductor so that the fastening means may contact the electrical wiring. If the fastening means are of metal (typically they are metal screws which in use extend into the box), this can result in a short circuit.

Thus, the present invention seeks to provide a means of preventing the conductor being damaged by the fastening means as they are employed to secure the removable cover to the box. This may be achieved by providing a shield means to prevent the conductor obstructing the path of the fastening means in the box, preferably at least at or near the base of the box. In this way, the conductor should not become trapped between the fastening means and the base or a side of the box.

Preferably the shield means comprises an enclosure in the box for receiving a fastening means, suitably for defining a generally closed chamber for a fastening means.

The shield means may be securable to the interior and/or the exterior of the box. In addition, the shield means may be mountable to the base and/or side walls of the box. In some preferred embodiments cut outs are provided on the box and are deflected to provide means for engaging the shield means. Thus, the cut outs may be deflected to define resilient clips for retaining the shield means, for example.

Alternatively or in addition, the box may be provided with one or more apertures (in the base and/or side wall) arranged to receive surface formations on the shield means. In this regard the shield means may include deflectable lugs, each adapted to pass through an aperture in the box and subsequently to be deflected to one side of the aperture to inhibit withdrawal of the shield means from the box.

The fastening means typically employed with wall boxes are metal screws and thus the present wall boxes are preferably adapted to engage screw threaded fastening means. In preferred embodiments the shield means has one or more screw threaded apertures for engaging such fastening means. In particularly preferred embodiments the shield means defines a passage to receive at least the free end of a screw.

In some preferred embodiments, the wall box is provided with a bracket which extends inwardly from a side wall of the box. Suitably the bracket has a flange part arranged substantially perpendicular to a side wall of the box, the bracket having a screw threaded aperture for engaging a screw of the fastening means. In this regard, preferably the bracket and shield means together define a chamber for the fastening means.

In such embodiments the bracket may be made as a separate component and subsequently secured to a side wall of the box. Alternatively, a part of a side of a box may be deflected inwardly to provide an integral bracket.

In embodiments where a separate bracket component is employed, the bracket is preferably transversely movable with respect to the wall of the box. In this way the bracket may be moved so as to be correctly aligned with a cover plate even if the wall box has been fitted to the wall slightly askew.

For similar reasons to those mentioned above, the shield means may be adapted to be transversely movable in addition to, or as an alternative to, any bracket.

Typically, it will only be necessary for one bracket/shield means to be adjustable in this way.

In preferred embodiments the shield means are made of metal, preferably stamped out of sheet metal. In other practical embodiments the shield means may be moulded from a plastics material.

Preferably a shield means is provided for each fastening means required for securing a cover to the wall box. Clearly, all the shield means may be the same or different, as desired.

The present invention also concerns a wall box provided with a cover, fastening means for securing the cover to the box and means for shielding any conductors in the box from the fastening means.

Embodiments of the present invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figs. 1 to 3 show how a shield means may be provided in a box, according to a first embodiment; Figs. 4 to 8 illustrate an alternative adjustable shield means; Figs. 9 to 11 illustrate a shield means according to a third embodiment; Fig. 12 shows a shield means according to a fourth embodiment; Fig. 13 to 16 illustrate a fifth embodiment of the invention; Fig. 17 illustrates a sixth embodiment of the invention; Fig. 18 shows a seventh embodiment of the invention; Figs. 19 to 21 illustrate an alternative embodiment of the present invention; Fig. 22 illustrates a modification to the embodiment of Figs. 19 to 21; Fig. 23 and 24 illustrate a further embodiment of the present invention;; Figs. 25 to 28 show an adjustable shield means according to an eleventh embodiment; Figs. 29 to 32 illustrate a twelfth embodiment of the present invention; Figs. 33 to 34 illustrate a further embodiment of the present invention; Figs. 35 and 36 illustrate a modification to the previous embodiment; Figs. 37 to 39 show a fifteenth embodiment of the invention; Figs. 40 and 41 show a further embodiment of the present invention; and Figs. 42 and 43 illustrate additional embodiments of the present invention.

Referring now to Figs. 1 to 3 the illustrated wall box comprises a generally rectangular base 10 having side walls 11, 12, and 13 and 14 extending upwardly from its periphery. The box is fabricated from a one piece blank of sheet metal. To make the box the sides are bent up from the base and locked together using tabs 15 and 16, in a known manner.

The side walls 11, 12, 13, 14 and base 10 of the box are provided with a number of knock-out panels, one of which is indicated by numeral 17. The knock-outs 17 receive the electrical flex for connection to a cover plate (not shown). The cover plate supports the switch, socket or other piece of electrical apparatus to be mounted in the wall box.

Slidably mounted against the upright side wall 11 is a shield means in the form of a cover screw enclosure 20.

The enclosure 20 is fabricated from a flat sheet of metal folded to define a body portion 21, a tongue 22 and wing members 24. In more detail, the enclosure 20 has an elongate hollow body portion 21 of generally semicircular configuration, closed at one end by a tongue 22 and at the other end by base 10. The tongue 22 is provided with a screw threaded aperture 23, to receive a screw threaded fastening means for the cover plate.

Wing members 24 extend outwardly from either side of the tongue 22, in a plane generally at right angles thereto and parallel to side wall 11. The wings 24 are secured alongside the side wall 11 by a pair of downwardly directed lugs 26 which are struck out from the side wall 11. A pair of lugs or indentations 27 also support the wings 24 and help to hold enclosure 20 off the base 10. In this way enclosure 20 is capable of limited sliding movement alongside side wall 11 on the lugs 27 and within the lugs 26. The extent of this transverse movement of the enclosure 20 is limited by engagement of the lugs 26 with the body 21.

In use, the hollow enclosure 20 accommodates the screw threaded fastening means to prevent an electrical conductor being trapped between the fastening means and the base or side walls of the box to damage the conductor.

Against the opposite side wall 13, there is illustrated a so-called fixed cover screw enclosure 20'.

This enclosure 20' corresponds to that indicated at 20, although it is secured to the side wall 13 in a different manner. This enclosure 20' has an elongate hollow body portion 21' and deflected apertured tongue 22'. A pair of deflectable wings 28 also extend from opposite edges of the body 20'. The wings 28 correspond to wings 24 of the enclosure 20, but in this case they are arranged to extend through slots 29 in the wall 13. The wings 28 may be deflected towards or away from each other to retain the enclosure 20' in fixed relation to side wall 13.

Referring now to Figs. 4 to 8, a shield means is provided, which includes an enclosure member 30 and attachment bracket 40, both fabricated from a flat sheet of metal deflected to the desired shape. In member 30 two ends of a sheet bent over to provide a front panel 31 and two short side panels 32 and 33. A lug 34 extends from each side panel 32, 33 respectively and each lug 34 is arranged to pass through a slot 29 in the wall 11, illustrated in Fig. 8. The lugs 34 are bent over or deformed at the exterior of the box to retain the enclosure member 30 in fixed relation to the wall 11.

Thus a compartment or chamber 35 is formed within the box by enclosure member 30, side wall 11, and base 10, to house a fastening means such as a screw. This will prevent the screw coming into contact with the electrical conductors in the box proper.

The attachment bracket 40 comprises a body 41 in the form of a flat metal strip supporting a deflected tongue 42 which extends therefrom at an angle of about 90". The tongue 42 is provided with a screw threaded aperture 23 as in the previous embodiment, to receive a cover retaining screw.

The bracket 40 is mounted above an open end of the chamber 35 of the member 30. The bracket body 41 is secured generally parallel to the wall 11 by the deflectable lugs 26, as in the previous embodiment. A metal lip 23A around threaded aperture 23 in bracket 40 limits the extent of sliding movement of the bracket 40 by engagement with the sides 32 and 33. Other means may be provided to limit said transverse movement if desired.

It will be appreciated that this example differs from the previous embodiment in that the enclosure 30 as a whole does not move relative to the wall 11.

Turning now to Figs. 9 to 12, there is illustrated a shield means comprising an enclosure 220 which is in fixed relation to the box side wall 11. Generally one fixed enclosure and one adjustable enclosure would be provided within a box, on opposing walls as illustrated in Fig. 1. However, the box illustrated in this embodiment is deep drawn and is intended for surface mounting. Thus, satisfactory results may be obtainable with only fixed enclosures. In this embodiment the enclosure 220 comprises a generally semicircular body portion 221, closed at one end by an integral deflected tongue 222. The tongue has a screw threaded aperture, as before. Fixing lugs 228 and 228' extend from the tongues 222 and body portion 221 respectively.

The lug 228 shown in Fig. 11 would pass through aperture 29 in the side wall 11 and lug 228' would pass through aperture 29' in base 10. Preferably the lug 228 which passes through the side wall 11 will be deformed as opposed to being bent over, to retain the enclosure 220 in fixed relation to the box. The vertically depending lug 228' on the enclosure simply locates in a slot 29' provided in the base 10.

Fig. 12 shows an alternative enclosure member 220' supporting two lugs 228'' which would engage a box wall provided with two corresponding vertical slots.

Referring now to Figs. 13 to 16, they show a fixed cover screw enclosure comprising, in combination, a generally semicircular tongue 50 with threaded aperture 51, punched out of the box side wall 11. An annular metal lip 52 is presented around aperture 51. One end of a hollow tube member 55 or 55'(see Fig. 15) locates on the displaced metal lip 52. The other end of the tube member 55, 55' locates over a raised hump or protrusion 53 extending upwardly from the base 10, as shown in Fig.

14. Thus, the tube member 55 provides a fixed housing or enclosure for the cover retaining screw 18. The arrangement is illustrated in more detail in Fig. 16.

As shown in Fig. 15 a tube member 55' may be provided which has a flat face 57 and which in use, would blank off the aperture 54 formed in the wall 11 by punching tongue 50 therefrom. This may be effective in preventing ingress of plaster or cement through aperture 54.

Fig. 17 shows further alternative enclosure members suitable for use with a box such as illustrated in Figs.

13 and 16. In this case, an enclosure member 155 or 155' is a cylinder of a shape corresponding to that of deflected tongue 50, in this case of generally semicircular cross section. The 155' version is made of a single sheet of metal which has its free ends bent to face towards one another to define a semicircular cylinder. The free ends of the sheet need not be secured together to produce the enclosure 155'. An enclosure such as 155 is a unitary body and may be made by moulding or welding, for example.

Fig. 18 illustrates another embodiment of the invention which includes a deflected tongue 50. In this case a generally semicircular tongue 130 is also stamped and deflected from base 10 of the box to expose an aperture 132. The tongue 130 carries a slot 129. An enclosure member 255 has a lug 128 for engagement with slot 129, once tongue 130 is deflected upwardly in line with base 10. In this embodiment a unitary flat wall 257 of the enclosure member 255 blocks aperture 54 in the side of the box which. helps to seal the box against undesirable ingress of moisture, plaster etc.

As an alternative, the lug 128 may be omitted from the enclosure member 255. In this regard, the enclosure member may be retained in position in the box by engagement with a protrusion in the base of the box (such as illustrated at 53 in Fig. 14).

Referring now to Figs. 19 to 24, they illustrate further examples of fixed cover screw shield means according to embodiments of the invention. Figs. 19 to 21 illustrate an enclosure 60 in combination with a cover plate 65. The enclosure 60 is formed by deforming the side wall 11 to provide a recess externally of the box.

At the top of the recess 60 there is a deflected tongue part 61 provided with a threaded aperture 23 (see Fig.

21).

The cover plate 65 is shown in more detail in Fig.

20. The plate 65 is in the form of a flat piece of metal 66 having lugs 328 extending from two opposite edges, generally perpendicular to the plane of the plate 65.

The lugs 328 are arranged to pass through slots 29 in the wall 11, from the outside of the box to the inside. Once inserted into slots 29 the lugs 328 are bent over to retain the plate 65 in fixed relation to the side wall 11. In this position plate 65 prevents ingress of plaster or cement into the enclosure.

Figs. 22 to 24 illustrate alternatives to the previous embodiment. In Figs. 23 and 24, rather than including the back plate 65, a hollow tube 55 locates between the base 10 and the tongue part 61 of the deflected part of side wall 11. The tube 55 is retained therein by an annular deflected lip 152 in screw threaded aperture 23 and the protrusions 153 on base 10.

As a further alternative, a tongue 67 may be provided on a cover plate 65' as shown in Fig. 22. The tongue 67 may be provided with a threaded aperture 23 to eliminate the need for a tongue 61 to be deflected from side wall 11 as shown in Fig. 17. In this case the side wall 11 would have a slot to receive tongue 67.

Turning now to Figs. 25 to 28 a further adjustable, cover screw enclosure 70 fabricated from a flat piece of metal. The enclosure 70 has a body portion 71 of substantially semicircular configuration, with its upper end closed by an integral deflected tongue 322. The tongue 322 is provided with a threaded aperture 23 and an elongated slot 72. A mounting bracket 75 is also provided for use in combination with the enclosure member 70.

The bracket 75 comprises a strip of stamped out metal 76 having a lug 77 extending generally centrally therefrom. The lug 77 is arranged to locate in the elongated slot 72 in the tongue 322, although it is not as wide as the tongue 322. In use, the tongue 322 is bent inwards to render the bracket 75 captive on the enclosure 70 as shown in Fig. 27. The enclosure and bracket sub-assembly 70, 75 is then mounted on the box side wall 11. The lug 77 projects sufficiently to pass through a slot 29 in the side wall 11. The lug 77 is subsequently deformed in a known manner to render the said sub-assembly captive on the side wall 11.

In this way, the bracket 75 is fixed relative to the side wall 11. The enclosure member 70 is free to be moved transversely on and relative to the bracket 75 and wall 11 because the slot 72 on the enclosure member 70 is of greater length than the width of the lug 77.

Transverse movement of the enclosure 70 is limited by the engagement of said lug 77 with the ends of the slot 72.

Figs. 29 to 32 illustrate an adjustable shield means according to a further embodiment. In this case an enclosure member 130 is made of sheet metal deflected to provide a front panel 131 and side panels 132, 133 respectively. Lugs 134 extend from and beyond each side panel 132, 133, and generally perpendicularly to front panel 131. A mounting bracket 141 is also provided.

This comprises an elongate strip of metal 142 having two spaced slots 145 and a deflected, generally semicircular tongue 142. The tongue 142 has a screw threaded aperture 23.

In this embodiment, the side wall 11 of the box is provided with two spaced vertical slots 29 and two spaced horizontally extending deflected lugs 26A. As illustrated in Fig. 29, the lugs 26A are arranged to interengage apertures 145 on mounting bracket 140. Also, slots 29 in side wall 11 may accommodate lugs 134 of enclosure member 130. The lugs 134 are deflected towards or away from one another to retain the member 130 against side wall 11. The bracket 140 is transversely movable over lugs 26A to provide a degree of adjustability to the enclosure.

Figs. 33 and 34 illustrate an alternative to the previous embodiment. In this case an enclosure member 230 has a front panel 231 and side panels 232 and 233 respectively. Deflectable lugs 234 extend outwardly from the top of the side panels 232, 233 and a further lug 235 extends downwardly from the base of front panel 231. A mounting bracket 240 having a deflected tongue 242, elongate apertures 245 and a screw threaded aperture 23, similar to that of the previous embodiment is also provided.

In this case, lug 235 will engage an aperture or slot 29 in base 10 of the wall box. Lugs 234 pass through apertures 245 in the mounting bracket 240 and matching apertures (not illustrated) in side wall 11.

The lugs 234 are deflected towards or away from one another -to hold the enclosure member 230 firmly in position with respect to the wall box. However, the bracket 240 is transversely movable over lugs 234 to confer some adjustability to the shield means.

Figs. 35 and 36 illustrate a modified version of the previous embodiment. In this case an enclosure member 330 has front and side panels 331, 332 and 333 as before.

Lugs 334 extend from the side panels 332, 333. Each side panel also has a recess 336 adjacent the lug 334. The mounting bracket 340 is simply a strip of metal 341 having an apertured deflected tongue 342.

In this embodiment the enclosure member 330 is fixedly mountable to side wall 11 and base 10 of the box by way of lugs 334 and 335, as in the previous embodiments. However, in this case, the strip 341 of the mounting bracket 340 is received in recesses 336 of the enclosure member 330 which permits transverse movement of the bracket 340 with respect to the enclosure member 330.

Turning now to Figs. 37 to 39, they illustrate a further embodiment of the invention. An enclosure member 30, as illustrated in previous Fig. 5 may be employed with an alternative type of mounting bracket 440, comprising a back plate 441 having an elongate slot 445 and a tongue 442 deflected with respect to plate 441.

The enclosure member 30 may be secured to side wall 11 as in the earlier embodiment. In this case however the bracket 440 is secured at aperture 429 in side wall 11 by a hook member 447 which passes through its slot 445. The bracket 440 is transversely movable by sliding slot 445 over hook member 447.

Figs. 40 and 41 show a further embodiment of the invention which is particularly preferred. In this case a sheet of metal is cut and deflected to provide an enclosure member 530 having a front panel 531, and side panels 532, 533 generally perpendicular thereto. Each side panel 532, 533 is also deflected through about 90" to define wings 532', 533' respectively. The enclosure member 530 also has a deflected top panel 522 folded through about 90" with respect to both the front panel 531 and side panels 532 and 533. The top panel 522 has a threaded aperture 23.

The wall box has an upstanding lug 553 stamped out of the base 10 and two depending lugs 526 stamped out of side wall 11. The enclosure member 530 may be secured to the wall box as illustrated in Fig. 40. The lugs 526 permit some transverse displacement of the enclosure member 530.

This embodiment of the invention is particularly preferred because it provides an adjustable shield means of quite simple and cost-effective construction.

Fig. 42 illustrates an alternative enclosure member 630 having front panel 631, side panels 632, 633 and an apertured top panel 622 provided with a deflectable lug 628 at its free end. In this case the enclosure member 630 may be secured to the side wall 11 by engaging lug 628 in a slot 29 in the wall 11 and deflecting the lug at the exterior of the box.

Fig. 43 illustrates that a lug 628' could also depend from the bottom of a front panel 631 for engagement in a slot in a base of the box. This would avoid the need for an upstanding lug on the base of the box, as illustrated in the previous figure.

It will be appreciated that various modifications may be made to the illustrated embodiments. For example, surface formations (such as lugs or slots) of various configurations may be provided on the base and/or side wall of the box for securing a shield means in position.

Also, the shield means may be constructed of various parts secured together, although those made from a sheet of metal deflected into the desired configuration may be preferred in terms of ease of manufacture.

Clearly, a wall box may be provided with any combination of fixed and/or adjustable shield means as illustrated in various embodiments.

In addition, it will be appreciated that shield means of various sizes and configuration, other than those illustrated could be effective in reducing likelihood of damage to a conductor. For example, the shield means need not be arranged to define a closed chamber for essentially the full extend of the fastening means. For example, the shield means could be arranged to accommodate only the free end of the fastening means.

In addition, the shield means need not be constructed of sheet metal as illustrated. Instead, it could be made of a perforated material, provided that the conductors in the box are unlikely to penetrate the perforated material to obstruct the path of an advancing fastening means as it is secured to the box.

Claims (23)

1. A wall box for accommodating an electrical conductor, the box comprising a base, side walls upstanding from the base and an open front, the open front being closable by a removable cover andfastening means for securing the cover to the box, means being provided in the box for shielding the conductor from the fastening means as the cover is secured to the box.

2. A wall box according to claim 1 made of metal.

3. A wall box according to claim 1 or 2 wherein shield means are provided at least at or near the base of the box.

4. A wall box according to any preceding claim wherein the shield means comprises an enclosure in the box for receiving a fastening means.

5. A wall box according to any preceding claim wherein the shield means defines a chamber in the box for the fastening means.

6. A wall box according to any preceding claim wherein the shield means is securable to the box at the interior of the box.

7. A wall box according to any preceding claim wherein the shield means is securable to the box at the exterior of the box.

8. A wall box according to any preceding claim wherein the shield means are mountable to a side wall of the box.

9. A wall box according to any preceding claim wherein the shield means are mountable to the base of the box.

10. A wall box according to any preceding claim wherein one or more cut-outs are provided on the box and which are deflected to provide means for engaging the shield means.

11. A wall box according to any preceding claim wherein the box has one or more apertures adapted to receive and interengage with surface formations on the shield means.

12. A wall box according to any preceding claim adapted to engage screw threaded fastening means.

13. A wall box according to claim 12 wherein the shield means has a screw threaded aperture for engaging the fastening means.

14. A wall box according to any one of claims 1 to 12 having a bracket extending inwardly from a side wall of the box and which bracket is adapted to engage the fastening means for securing the cover to the box.

15. A wall box according to claim 14 wherein the bracket and shield means together define a chamber for the fastening means.

16. A wall box according to claim 14 or 15 wherein one or more parts of a side wall of the box are deflected inwardly to provide a bracket.

17. A wall box according to claim 14 or 15 wherein the bracket is transversely movable with respect to the box.

18. A wall box according to any preceding claim wherein the shield means is transversely movable with respect to the box.

19. A wall box according to any preceding claim wherein the shield means is made of metal.

20. A wall box according to any one of claims 1 to 17 wherein one or more parts of the box are deflected inwardly to define the shield means.

21. A wall box according to any preceding claim wherein shield means are provided for each fastening means.

22. A wall box substantially as hereinbefore described with reference to, and as illustrated in any one of the accompanying Figs. 1 to 43.

23. A wall box as claimed in any preceding claim provided with a removable cover and with means for fastening the cover to the box.