GB2117573A

GB2117573A - Electrical accessory boxes

Info

Publication number: GB2117573A
Application number: GB08208041A
Authority: GB
Inventors: Patrick Hamilton Smith
Original assignee: C AND C MARSHALL Ltd
Current assignee: C AND C MARSHALL Ltd
Priority date: 1982-03-19
Filing date: 1982-03-19
Publication date: 1983-10-12
Also published as: GB2117573B

Abstract

The box which is for use in cavity walls has two substantially oppositely disposed apertures (22) in the side wall or walls (15) and two clamps (12, 13). Each clamp is mounted in the body (11) for swivellable movement between a first position in which a clamping arm (19) is within the body and a second position in which the clamping arm projects outwardly from the body through a respective aperture (22). Each clamp is also slidable along its swivellable axis so that in use the boxes can be mounted in a hole in the cavity wall and the clamping arms can be made to engage a rear face of the wall whilst the flanges (16) engage the front face thereof. Full securement of the box to the wall after an electrical component is connected, is ensured by means of a face plate which is fastened by screws threadedly engaged with apertures in swivel pillars 17. <IMAGE>

Description

SPECIFICATION Electrical accessory boxes This invention relates to electrical accessory boxes, e.g. electrical switch and socket boxes, for use in cavity walls.

The outer skins of cavity walls are often of relativeiy thin sheet material and it is not practical to secure an electrical accessory box in the wall in a conventional manner such as by the use of screws.

According to the present invention, there is provided an electrical accessory box compris ing a hollow body which is open at one end and which has a side wall or walls, one or more flanges extending outwardly from the side wall or walls at or adjacent the one end of the body and two substantially oppositely disposed apertures in the side wall or walls, and two clamps each mounted in the body adjacent to a respective aperture for swivella ble movement about an axis normal or substantially normal to the one end of the body between a first position in which a clamping arm of the clamp is within the body and a second position in which the clamping arm projects outwardly from the body through a respective aperture and for slidable movement in a direction parallel to said axis so that in use the box can be mounted in a hole in the cavity wall and the clamping arm can be made to engage the rear face of a sheet of material constituting part of the cavity wall whilst the flange or flanges engage the front face of the sheet.

Preferred and/or optional features of the invention are set forth in claims 2-8.

The invention will now be more particularly described, by way of example, with reference to the accompanying drawings in which: Figure 1 is a perspective view of one embodiment of an electrical accessory box according to the invention, and Figure 2 is a section through one side of the box and one of the clamps with the clamp shown engaging the rear face of a sheet of material constituting part of a partition wall.

Referring now to the drawings, the electrical accessory box shown therein provides a housing for electrical accessories such as switches and sockets and is suitable for use in cavity walls which comprise a pair of relatively thin sheets of material held in spaced relationship. The electrical accessory box indicated by the general reference number 10 has a body 11 formed of plastics material and two clamps 1 2 and 1 3 essentially formed of plastics material. The body 11 is open at one end, has a square base wall 14, side walls 1 5 and flanges 1 6 extending outwardly from the side walls at the open end of the box to define a continuous rim.

Each clamp 12, 1 3 comprises a pillar 17, a wing-like shield 1 8 which projects transversely from the pillar and a clamping arm 1 9 which projects from one face of the shield 1 8 and which has an outer edge 20 of generally arcuate shape centred on the longitudinal axis of the pillar.

The pillars 1 7 of the clamps 12 and 13 are mounted in sleeves 21 secured to or integral with the body 11. The sleeves 21 are positioned midway between the ends of two opposite side walls 1 5 of the body 11 and apertures 22 are provided in these two side walls adjacent to the clamps. The other two side walls are provided with knock-out portions 23 to provide cable entries.

As shown more particularly in Fig. 2, the pillar 1 7 of each clamp is hollow and has a threaded brass insert at its end adjacent to the open end of the body 11. At its other end, the pillar 1 7 is provided with four longitudinally extending slits which define four fingers 24 having barb-like formations at their free ends. This allows for insertion and retention of the pillar in the respective sleeve 21.

Each pillar 1 7 is mounted in its respective sleeve 21 for swivellable movement and axial sliding movement. Each pillar 1 7 is an interference fit in its respective sleeve 21 so that there is a frictional resistance to movement of the pillar relative to the sleeve. By swivelling each pillar 1 7 about its axis, the clamping bar 1 9 can be moved from a position in which it is disposed within the body 11 (see Fig. 1) to a position in which it projects outwardly from the body 11 through a respective aperture 22 and in which the respective shield 1 8 engages the side wall 14 and covers the aperture 22.

In order to locate the clamping arm in the position in which it projects outwardly through the aperture 22 and its associated shield 1 8 engages the side wa!l 14, the clamping arm 1 9 is provided with a pip cam 25 on its outer edge and adjacent to but spaced from the shield 1 8 and the body 11 is provided with a deflection bar 26 defined between the aperture 22 and an elongate slot 27. As the clamp 12, 1 3 is swivelled and the clamping arm 1 9 approaches its outermost position, the pip cam first deflects the deflection bar away from the aperture 22 and then releases the deflection bar so that the latter moves behind the cam to provide a degree of resistance to swivellable movement of the clamp in the opposite angular direction.The deflection bar engages the pip cam 25 and/or the outer edge 20 of the clamping arm when the clamping arm is in its outermost position so that the overall frictional resistance to slidable movement of the clamp relative to the body is sufficient to enable the clamps to hold the box in position in a cavity wall whilst cables are fed into the box and an electrical component is secured to the box.

In order to mount the box in a hole in a cavity wall, the clamps 1 2 and 1 3 are first swivelled so that the clamping arms 1 9 are disposed within the body 11 and the clamps are pressed towards the base wall 14. The body 11 is then positioned in the hole in the cavity wall and the clamps are swivelled until the clamping arms 1 9 are in their outermost position.

The clamps are then drawn towards the rear face of the sheet of material 28 (see Fig. 2) constituting part of the cavity wall whilst the flanges 1 6 engage the front face of the sheet 28. The clamps are to hold the box in position whilst cables are passed through one or more holes previously provided by knocking out one or more of the portions 23 and whilst an electrical component is connected to the box.

The electrical component will include a face plate shown in Fig. 2 in broken lines and given the reference numeral 29. The face plate will have holes therein for the reception of threaded bolts which will engage with the threaded inserts in the pillars 1 7. As the threaded bolts are screwed into the inserts, the clamping arms 1 9 will be drawn into tight engagement with the rear face of the sheet 28 and the electrical components will be secured to the box.

In the example described above, the flanges 1 6 define a continuous rim around the open end of the body 11, but it is only necessary to provide flanges adjacent to the clamps 1 2 and 13.

With the provision for axial as well as swivellable movement of the clamps, the clamping arms are able to grip cavity wall sheets of different thicknesses.

Of course, the base 1 4 may be of any other convenient shape such as of rectangular or circular shape.

Claims

1. An electrical accessory box comprising a hollow body which is open at one end and which has a side wall or walls, one or more flanges extending outwardly from the side wall or walls at or adjacent to the one end of the body and two substantially oppositely disposed apertures in the side wall or walls, and two clamps each mounted in the body adjacent to a respective aperture for swivellable movement about an axis normal or substantially normal to the one end of the body between a first position in which a clamping arm of the clamp is within the body and a second position in which the clamping arm projects outwardly from the body through a respective aperture and for slidable movement in a direction parallel to said axis so that in use the box can be mounted in a hole in the cavity wall and the clamping arm can be made to engage the rear face of a sheet of material constituting part of the cavity wall whilst the flange or flanges engage the front face of the sheet.

2. The box of Claim 1, wherein each clamp and the hollow body have interengageable means for locating the clamping arm in its second position.

3. The box of Claim 2, wherein the interengageable means comprises a deflection bar on the hollow body and a deflector cam on the clamping arm, the arrangement being such that as the arm moves from its first to its second position the cam first deflects the deflection bar and then releases the deflection bar so that the matter moves behind the cam.

4. The box of claim 3, wherein the deflection bar is integral with the body and is defined between a respective aperture and a slot in the body.

5. The box of any one of the preceding claims, wherein each clamp includes a pillar mounted for angular and axial movement in a sleeve integral with or secured to the body portion.

6. The box of claim 5, wherein the pillars mount internally screw-threaded inserts for the reception of threaded bolts which in use serve to draw the clamping arms into tight engagement with the sheet of material and serve to secure an electrical component to the box.

7. The box of any one of the preceding claims, wherein each clamp has a shield for covering the respective aperture when the clamping arm is in is second position.

8. The box of any one of the preceding claims, wherein each clamping arm has an outer edge of generally arcuate shape centered on the axis of the respective clamp.

9. An electrical accessory box substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.