GB2592852A

GB2592852A - Electrical component enclosures for recessed mounting

Info

Publication number: GB2592852A
Application number: GB1912754.7A
Authority: GB
Inventors: Camillus Tynan Joseph
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-05
Filing date: 2019-09-05
Publication date: 2021-09-15
Also published as: GB201912754D0; WO2021044054A1

Abstract

A pattress for recessed mounting in a panel 38 comprising an electrical component enclosure 10 having a body open at a front side 12 with a sidewall 14 extending rearwardly 16 and a rear wall 18. The body defines an interior space which can house an electrical component. A flange 22 at the front 12 of the body abuts against the front 40 of the panel when the body is flush mounted in a panel opening. The body is secured against the rear 42 of the panel by inserting a projecting portion 28 of a retaining member 24 through an aperture 26 in the sidewall 14, the retaining member 24 having a fixing portion 30 that remains in the interior space and a neck section 34 connecting the projecting portion 28 and fixing portion 30. The neck 34 locates within the aperture 26 and permits rotation of the projecting member 28 such that it is prevented from removal via the aperture 26 and is oriented to abut flat against the rear 42 panel face, secured by a fixture between a cover member such as a face plate and the fixing portion 30. Additionally, grub screws or set screws 44 or spacers may be placed to bear against the rear wall 18 and the fixing portion 30 such that the retaining members 24 are held in place against rearwards displacement.

Description

Electrical component enclosures for recessed mounting

Technical Field

This invention relates to electrical component enclosures for recessed mounting, and in particular to enclosures of the type known as dry lining boxes, which are mounted in use in apertures in wall panels, drywall, plasterboard and the like.

Background Art

The fitting of an electrical enclosure (such as a dry lining box, switch enclosure, socket box, or any similar enclosure] into a panel having front and rear faces, such as a hollow support wall member, requires some means of securing the enclosure to the panel.

It is often the case that the enclosure will be fixed to a structural element supporting the wall panel, such as a batten or stud on which the wall panel is mounted. However, such an approach limits the positioning achievable for the enclosure.

If the enclosure is in a box-like form that is intended to be closely flush-fitted into an aperture sized to receive the enclosure, then the fixing must be one which can be affixed from either the front of the enclosure or its interior, if multiple breaches of the wall panel are to be avoided.

An example of a mechanism can be seen in WO 93/08627. This discloses a dry lining box which has a pair of holding members mounted within the enclosure on pins, allowing them to be swivelled outwardly through sidewall apertures after the box is mounted into the wall panel. The holding members can then be brought forward to engage against the rear face of the wall panel and fixed into place.

It would be desirable to provide alternative and/or improved electrical enclosures for recessed mounting in wall panels.

Disclosure of the Invention

There is provided an electrical component enclosure for recessed mounting in a panel having front and rear faces, said enclosure comprising: a body having an opening at a front side thereof and a sidewall extending in a rearward direction from the front side, the body defining an interior space for housing an electrical component and the body being adapted to be flush mounted into a panel opening from the front face of said panel, said body; a flange disposed outwardly of said body at the front side thereof and adapted to abut against the front face of said panel when said body is flush mounted into said panel opening; an aperture provided in said sidewall and extending in the rearward direction; and a retaining member comprising: a projecting section having a cross-section permitting insertion from the interior space to the exterior of the sidewall through the aperture when in a first orientation and preventing retraction through the aperture when in a second orientation; a fixing portion adapted to engage with a fixture within the interior space, and a neck section connecting the projecting section to the fixing portion, the neck section being dimensioned to fit within the aperture and to travel along the aperture when the projecting section is in the second orientation.

This construction leads to a simple and secure method of flush mounting an electrical component enclosure to a panel in any position and without any need to breach the panel apart from creating the panel opening in which the enclosure is received. The retaining member can be inserted through the aperture from the exposed interior space in the enclosure body after flush mounting the body in the panel. Rotation of the retaining member is accommodated by the neck section rotating within the aperture, after which the projecting section is retained and may be oriented to be parallel to the rear face of the panel. By then drawing the retaining member forward in the aperture, the projecting section can be brought to bear against the panel's rear face, clamping the panel between it and the flange at the front of the enclosure body. Applying a suitable fastener then secures the retaining member in position.

Preferably, said aperture is an elongate slot.

Preferably, said slot extends rearwardly along an axis perpendicular to the plane of the flange.

Further, preferably, said projecting section is a flattened plate member dimensioned to fit through the slot when aligned with the axis of the slot and dimensioned not to fit through the slot when aligned normal to the axis of the slot Preferably, said aperture comprises an enlarged portion to facilitate the rotation of the neck section between the first and second orientations.

More preferably, said aperture is an elongate slot extending rearwardly along an axis perpendicular to the plane of the flange, and wherein said enlarged portion is positioned rearwardly along the slot a sufficient distance to accommodate the neck section when the projecting section has been fully inserted through the aperture.

Preferably, the enclosure comprises a plurality of said apertures each disposed in a sidewall of said body, and a plurality of said retaining members each adapted to be disposed in a respective aperture.

Further, preferably, the plurality of apertures comprise a pair of said apertures respectively provided in opposed sidewalls of said body, and the plurality of retaining members comprise a pair of said retaining members respectively disposed on said pair of apertures.

Typically, for an average sized enclosure, such as a dry lining box for domestic or commercial installation, a pair of apertures on either side face, each having a respective retaining member, will properly secure the enclosure to the panel. It will be appreciated however that if greater fixing power is needed, then additional apertures and retaining members can be provided.

The number of apertures may be greater than the number of fixing members employed. This permits the installer to choose from different aperture positions according to the orientation of the enclosure, the design of the cover plate to be employed, the existence of obstructions behind the panel, the configuration of components within the enclosure and of wiring entering the enclosure, and so on.

Preferably, the opposed sidewalls form part of a generally continuous peripheral sidewall of said body.

The skilled person will appreciate that various different technologies exist for making electrical enclosures, such as sheet metal stamping and folding, casting, moulding and so on. Many designs will employ a substantially continuous peripheral sidewall.

In a preferred embodiment said fixing portion comprises a mounting to receive a threaded fixture.

The mounting is preferably disposed with the axis for receiving a threaded fixture being perpendicular to the plane of the projecting portion, so that when in the second orientation, the projecting portion is generally parallel to the panel and the axis of a threaded fixture engaging the mounting is perpendicular to the panel.

Preferably, the enclosure further comprises a front member adapted to enclose the interior space when affixed to the body by means of a fixture which engages the fixing portion.

Such a front member may be referred to as a front plate, cover plate, and so on. It may be a simple plate-like member or it may incorporate switches, sockets, electrical components such as displays, or any other suitable equipment. It need not be planar or plate-like, and there are many possible designs that can be fitted to enclose a flush-mounted electrical enclosure.

Preferably, the or each aperture extends rearwardly in a direction normal to the flange.

In some embodiments it may be advantageous to provide means to prevent the retaining member being displaced rearwardly as the fixing portion is engaged by a fixture.

Preferably, said means to prevent the retaining member being displaced rearwardly is a threaded fixture extending rearwardly from the fixing portion which can be adjusted to set a minimum spacing between the fixing portion and a portion of the body.

Preferably, the fixing member is provided with said threaded member as a grub screw or set screw that can be advanced to bear against a feature of the body, such as for example the rear wall or a portion of the aperture, when the fixing member is in the desired position.

Said means to prevent the retaining member being displaced rearwardly may for example be in the form of a spacer adapted to be inserted rearwardly of the fixing portion or neck portion and to engage with a portion of the body.

The electrical component enclosure may be provided as a kit of parts, comprising a plurality of spacers to facilitate positioning the retaining member at a plurality of alternative positions corresponding to different panel thicknesses.

The portion of the body from which a minimum spacing is set is preferably S selected from a rear wall of the body and the aperture.

There is also provided a method of recessed mounting an electrical component enclosure in a panel haying front and rear faces, comprising the steps of: fitting an enclosure body into a panel opening provided in the front face of said panel, the enclosure body having an opening at a front side thereof and a sidewall extending in a rearward direction from the front side, the enclosure body defining an interior space for housing an electrical component; positioning the enclosure body to be flush mounted with a flange provided on the front of the body abutting the front face of the panel; securing, in a rearwardly-extending aperture in said sidewall, a retaining member comprising: a generally projecting section having a cross-section permitting insertion from the interior space to the exterior of the sidewall through the aperture in a first orientation and preventing retraction through the aperture in a second orientation; a fixing portion adapted to engage with a fixture within the interior space, and a neck section connecting the projecting section to the fixing portion, the neck section being dimensioned to fit within the aperture and to travel along the aperture when the projecting section is in the second orientation; wherein securing the retaining member comprises: inserting the projecting section through the aperture in said first orientation such that the projecting section is located behind the rear face of the panel on the exterior of the enclosure body and the fixing portion is located within the enclosure body; rotating the retaining member to said second orientation to prevent it being retracted through the aperture; moving the retaining member forward until the projecting section abuts the rear face of the panel; and engaging the fixing portion with a fixture to secure the retaining member in position.

Preferably, engaging the fixing portion with a fixture comprises: fitting a cover member to the front of the enclosure body to enclose the interior space; engaging a fixture which cooperates with the cover member and the fixing portion to secure the cover member to the enclosure and to secure the enclosure to the front panel by the action of the fixture on the retaining member.

Preferably, engaging the fixing portion with a fixture further comprises engaging the fixing portion with a means to prevent the retaining member being displaced rearwardly prior to fitting said cover.

Brief Description of the Drawings

The invention will now be illustrated by the following description of embodiments thereof, given by way of example only with reference to the accompanying drawings, in which: Figs. 1 and 2 are perspective views of an electrical component enclosure; Fig. 3 is a front view of the enclosure of Fig. 1; Fig. 4 is a side view of the enclosure of Fig. 1; Fig. 5 is a bottom view of the enclosure of Fig. 1; Fig. 6 is a perspective view of a retaining member of the enclosure of Fig. 1; Fig. 7 is an end view of the retaining member of Fig. 6; Fig. 8 is a front view of the retaining member of Fig. 6; Fig. 9 is a side view of the retaining member of Fig. 6; Fig. 10 is a perspective view of the enclosure of Fig. 1 with a first retaining member in place and a second retaining member in the process of being fitted; Fig. 11 is an enlarged detail of the portion of Fig. 10 outlined in a circle; Fig. 12 is a front view of the enclosure of Fig. 1, when in the configuration shown in Fig. 10; Fig. 13 is a side view of the enclosure of Fig. 1, when in the configuration shown in Fig. 10; Fig. 14 is a bottom view of the enclosure of Fig. 1, when in the configuration shown in Fig. 10; Fig. 15 is a perspective view of the enclosure of Fig. 1 when in position in a panel opening; Fig. 16 is an enlarged detail of the portion of Fig. 15 outlined in a circle; Fig. 17 is a side view of the enclosure of Fig. 1 when in position in a panel opening; Fig. 18 is a cross-sectional view taken through the Fig. 17 view; Fig. 19 is a front view of an alternate embodiment of retaining member; Fig. 20 is a cross-section through the retaining member of Fig. 19, when aligned perpendicular to a sidewall in which it has been inserted; and Fig. 21 is a cross-section through the retaining member of Fig. 19, when aligned at a non-perpendicular angle to a sidewall in which it has been inserted

Detailed Description of Preferred Embodiments

Referring to Figs. 1-5, there is indicated generally at 10 an electrical component enclosure in the form of a dry lining box. The enclosure 10 includes a body having an open front 12, a peripheral sidewall 14 extending rearwardly 16, and a rear wall 18. The peripheral sidewall is formed of four wall sections namely a left wall 14a, a top wall 14b, a right wall 14c and a bottom wall 14d.

The box of the illustrated embodiment is made from pressed steel and, as is well-known in the art, a number of knockouts 20 are provided in the sidewall and rear wall to accommodate electrical connections between an external electrical circuit and components (not shown) located in or attached to the enclosure 10. The skilled person will readily appreciate that the invention is in no way confined to this construction technique or this material, and any suitable material or construction technique may be used instead of pressed steel.

A set of flanges 22 project outwardly from the periphery of enclosure 10 at the front side 12. When the enclosure 10 is mounted in a suitably sized opening in a panel, the flanges 22 will abut against the front face of the panel to flush mount the enclosure.

At either side, i.e. in the left sidewall 14a and right sidewall 14c, a respective retaining member 24 is mounted in a respective aperture or slot 26 (see for example Fig. 2). The aperture or slot 26 is an elongate slot that extends through the sidewall in a rearward direction along an axis normal to the plane of the flanges 22.

Referring additionally to Figs 6-9, the retaining member can be seen in isolation.

Each retaining member, indicated generally at 24, comprises a flattened plate member 28 having a height H-1-1 (see Figs. 7 and 9) that is slightly less than the height (or smallest dimension) of the slots 26, and a length L-L (Fig. 8) which is less than the length (or longest dimension) of the slots 26. The depth D-D (Fig. 8) of the flattened plate member is chosen to ensure a good clamping action against the rear face of the panel in which the enclosure is mounted as will be explained further below.

The retaining member also comprises a fixing portion 30 adapted to engage with a fixture (not shown). In the illustrated embodiment, the fixing portion 30 is provided with a female threaded hole 32 to receive a conventional screw fixing of the type commonly used to secure a front plate of a junction box, switch box or socket box to a conventional threaded lug commonly found inside the enclosure to which the front plate mounts. It can be seen from Fig. 30 that the height of the fixing portion 30 is greater than the height of the flattened plate member, which serves both to provide a longer internal thread for better receiving and securing to a screw, and also to prevent the fixing portion from passing through the slot 26 since it is thicker in each dimension than the height of the slot.

Connecting the fixing portion 30 to the plate member 28 is a neck portion 34. The neck portion is dimensioned to fit closely within the height of the slot and the separation or gap provided by the neck portion 34 between the fixing portion and the plate member 28 is slightly greater than the thickness of the enclosure sidewall material in the vicinity of the slot. The neck portion can therefore slide along the slot, and depending on the tolerances and dimensions chosen, this sliding can be free or frictional, the latter being perhaps advantageous to assist in holding the components in place during the mounting and securing of the enclosure.

A second threaded hole 35 in the fixing portion is provided to receive a set screw or grub screw (not shown) which allows the minimum spacing between the fixing portion and the rear 18 of the enclosure to be adjusted. This may help prevent the retaining member from being displaced backwardly when a screw fixing is being inserted from the front, and holds the fixing portion steady to receive such a screw fixing into the threaded hole 32.

In the illustrated embodiment, the neck portion has a generally square cross-section and is dimensioned to be a close fit within the slot 26. Accordingly, and referring to Fig. 4, to facilitate the neck portion being rotated within the slot, after the plate member has been fully pushed through the slot, the slot 26 has a notch 36 at its midpoint The notch is a slightly enlarged rounded cut-out which permits the neck to be rotated within the slot from a first orientation where the plate member 28 is aligned with the slot following insertion to a second orientation (as shown in Figs. 1-51 in which the plate member 28 is perpendicular to the slot and parallel to the flange.

Figs. 10-14 show the enclosure 10 with a pair of the retaining members 24, one on each side. The retaining member 24 at the right-hand sidewall 14c, shown in enlarged detail in Fig. 11, is in the first orientation having been just inserted into the slot but not pushed fully through; while the retaining member 24 at the left-hand sidewall 14a is in the second orientation, having been pushed fully through the slot and rotated to prevent it from being pushed back through the slot 26 into the interior space of the enclosure. It can be seen from Fig. 12 that when the retaining member is in the first orientation, the fixing portion 30 is oriented so that the threaded hole is not exposed to the front of the enclosure but in the second orientation, the threaded hole 32 is correctly aligned to receive a screw passing rearwardly into the enclosure from a front plate or cover member.

Referring to Figs. 15-17, the enclosure is shown mounted in position in a wall panel 38 (such as a sheet or drywall or plasterboard, though any panel having a suitable thickness might be used to mount the enclosure). The panel has a front surface 40 and a rear surface 42. Typically, the rear surface is inaccessible, such as when a sheet of panelling material has been affixed to wall studs.

The panel is prepared to receive the enclosure 10 by cutting an opening dimensioned to receive the body of the enclosure. A snug fit is usually recommended so that the borders of the opening are concealed by the flanges 22 when the enclosure is fitted into place. The enclosure 10 is flush mounted so that the flanges 22 bear against the front surface 40 of the panel and the body of the enclosure projects behind the rear surface of the panel as can be seen from Figs. 16 and 17.

To secure the enclosure in place, a respective retaining member 24 is passed through the slot 34 on each side of the box, i.e. the retaining member is held in the first orientation and the plate member 28 fed through the slot so that it projects behind the rear face of the panel, outside the enclosure. The fixing portion 30 remains inside the enclosure, and the neck portion is located in the notch 36.

Typically, the retaining members will have grub screws or set screws 44 already in place (Fig. 16).

Next the retaining members are each rotated to the second orientation, so that the plate member is brought parallel to and spaced apart from the rear surface 42 of the panel. Then, drawing the fixing portions 30 forward within the enclosure, the retaining member slides forwardly within the slot until the plate members 28 bear against the rear surface 42 of the panel. It can be seen from Fig. 16 that this results in the panel being clamped between the plate members 28 and the flanges 22. The grub screws are then advanced until they bear against the rear 18 of the enclosure (see Fig. 18), thereby holding the retaining members in place against rearward displacement It will be appreciated that the screws could equally act against some other feature of the enclosure such as against the rearmost part of the slot If the fit between the retaining member 24 and the slot 34 is a relatively close friction fit, a front plate or cover member can be secured to the enclosure via screws received in the fixing member. As such a screw is tightened, the skilled person will appreciate that it will exert force to draw the fixing portion (and hence also the plate member 28) forward to exert pressure on the rear face of the panel and secure the enclosure further. However, no great amount of force is required, and the main goal is to ensure that the flanges 22 and plate members 28 properly abut the panel on the front and rear faces to prevent any movement due to loose fitting.

As a further alternative to the set screws 44, the retaining member could be held in place by a spacer or shim. Such a spacer (not shown) will be shaped and dimensioned to prop the fixing portion or the neck portion in position after the correct longitudinal position along the slot has been reached and before securing the fixing portion with a fastener.

A spacer may be adjustable or of fixed dimensions. Advantageously, a number of spacers can be provided, each adapted to ensure correct positioning of the fixing portion when the enclosure is fitted to standard thicknesses of panel. The spacer will typically engage the fixing portion and either the rear face of the enclosure or the end of the slot preventing rearward displacement as the fastener is secured in the fixing portion.

Referring to Figs. 19-21 an alternate design is shown for the retaining member, which omits the threaded hole 35 for a set screw, but which is of increased thickness, as can be seen from Fig. 20 which shows the retaining member of Fig. 19 in a cross-section taken along the line XX-XX. By designing the neck 34 to be only slightly thicker than the sidewall 14 which it accommodates, the retaining member can be designed to be freely movable along the slot when it is perpendicular to the sidewall as shown in Fig. 20 where the angle A is 90 degrees. However, if the retaining member is disposed at an angle A' which is a few degrees greater than or less than 90 degrees as shown in Fig. 21, it binds at the points B and is prevented from freely sliding along the slot. By choosing the dimensions appropriately, the angle A' can be chosen to be an angle at which the screw hole 32 would still receive a screw inserted blindly from the front cover to engage with the threads thereof.

The invention is not limited to the embodiments disclosed herein which may be varied or modified without departing from the scope of the claims.

Claims

Claims 1. An electrical component enclosure for recessed mounting in a panel having front and rear faces, said enclosure comprising: a body having an opening at a front side thereof and a sidewall extending in a rearward direction from the front side, the body defining an interior space for housing an electrical component and the body being adapted to be flush mounted into a panel opening from the front face of said panel, said body; a flange disposed outwardly of said body at the front side thereof and adapted to abut against the front face of said panel when said body is flush mounted into said panel opening; an aperture provided in said sidewall and extending in the rearward direction; and a retaining member comprising: a projecting section having a cross-section permitting insertion from the interior space to the exterior of the sidewall through the aperture in a first orientation and preventing retraction through the aperture in a second orientation; a fixing portion adapted to engage with a fixture within the interior space, and a neck section connecting the projecting section to the fixing portion, the neck section being dimensioned to fit within the aperture and to travel along the aperture when the projecting section is in the second orientation.
2. An electrical component enclosure according to claim 1, wherein said aperture is an elongate slot.
3. An electrical component enclosure according to claim 2, wherein said slot extends rearwardly along an axis perpendicular to the plane of the flange.
4. An electrical component enclosure according to claim 2 or 3, wherein said projecting section is a flattened plate member dimensioned to fit through the slot when aligned with the axis of the slot and dimensioned not to fit through the slot when aligned normal to the axis of the slot.
5. An electrical component enclosure according to any preceding claim, wherein said aperture comprises an enlarged portion to facilitate the rotation of the neck section between the first and second orientations.
6. An electrical component enclosure according to claim 5, wherein said aperture is an elongate slot extending rearwardly along an axis perpendicular to the plane of the flange, and wherein said enlarged portion is positioned rearwardly along the slot a sufficient distance to accommodate the neck section when the projecting section has been fully inserted through the aperture.
7. An electrical component enclosure according to any preceding claim, comprising a plurality of said apertures each disposed in a sidewall of said body, and a plurality of said retaining members each adapted to be disposed in a respective aperture.
8. An electrical component enclosure according to claim 7, wherein the plurality of apertures comprise a pair of said apertures respectively provided in opposed sidewalls of said body, and the plurality of retaining members comprise a pair of said retaining members respectively disposed on said pair of apertures.
9. An electrical component enclosure according to claim 7, wherein the opposed sidewalls form part of a generally continuous peripheral sidewall of said body.
10. An electrical component enclosure according to any preceding claim, wherein said fixing portion comprises a mounting to receive a threaded fixture.
11. An electrical component enclosure according to claim 10, wherein the mounting is disposed with the axis for receiving a threaded fixture being perpendicular to the plane of the projecting portion, so that when in the second orientation, the projecting portion is generally parallel to the panel and the axis of a threaded fixture engaging the mounting is perpendicular to the panel.
12. An electrical component enclosure according to any preceding claim, further comprising a front member adapted to enclose the interior space when affixed to the body by means of a fixture which engages the fixing portion.
13. An electrical component enclosure according to any preceding claim, wherein the or each aperture extends rearwardly in a direction normal to the flange.
14. An electrical component enclosure according to any preceding claim, further comprising means to prevent the retaining member being displaced rearwardly as the fixing portion is engaged by a fixture.
15. An electrical component enclosure according to claim 14, wherein said means to prevent the retaining member being displaced rearwardly is a threaded fixture extending rearwardly from the fixing portion which can be adjusted to set a minimum spacing between the fixing portion and a portion the body.
16. An electrical component enclosure according to claim 15, wherein the fixing member is provided with said threaded member as a grub screw or set screw that can be advanced to bear against a feature of the body when the fixing member is in the desired position.
17 An electrical component enclosure according to claim 14, wherein said means to prevent the retaining member being displaced rearwardly is a spacer adapted to be inserted rearwardly of the fixing portion or neck portion and to engage with a portion of the body.
18. An electrical component enclosure according to claim 17, provided as a kit of parts, and comprising a plurality of spacers to facilitate positioning the retaining member at a plurality of alternative positions corresponding to different panel thicknesses.
19. An electrical component enclosure according to any of claims 15-18, wherein the portion of the body is selected from a rear wall of the body and the aperture.
20. A method of recessed mounting an electrical component enclosure in a pan& having front and rear faces, comprising the steps of: fitting an enclosure body into a panel opening provided in the front face of said panel, the enclosure body having an opening at a front side thereof and a sidewall extending in a rearward direction from the front side, the enclosure body defining an interior space for housing an electrical component; positioning the enclosure body to be flush mounted with a flange provided on the front of the body abutting the front face of the panel; securing, in a rearwardly-extending aperture in said sidewall, a retaining member comprising: a projecting section having a cross-section permitting insertion from the interior space to the exterior of the sidewall through the aperture in a first orientation and preventing retraction through the aperture in a second orientation; a fixing portion adapted to engage with a fixture within the interior space, and a neck section connecting the projecting section to the fixing portion, the neck section being dimensioned to fit within the aperture and to travel along the aperture when the projecting section is in the second orientation; wherein securing the retaining member comprises: inserting the projecting section through the aperture in said first orientation such that the projecting section is located behind the rear face of the panel on the exterior of the enclosure body and the fixing portion is located within the enclosure body; rotating the retaining member to said second orientation to prevent it being retracted through the aperture; moving the retaining member forward until the projecting section abuts the rear face of the panel; and engaging the fixing portion with a fixture to secure the retaining member in position.
21. The method of claim 20, wherein engaging the fixing portion with a fixture comprises: fitting a cover member to the front of the enclosure body to enclose the interior space; engaging a fixture which cooperates with the cover member and the fixing portion to secure the cover member to the enclosure and to secure the enclosure to the front panel by the action of the fixture on the retaining member.
22. The method of claim 20 or 21, wherein engaging the fixing portion with a fixture further comprises engaging the fixing portion with a means to prevent the retaining member being displaced rearwardly prior to fitting said cover.