GB2582219A

GB2582219A - Electrical fitting

Info

Publication number: GB2582219A
Application number: GB2001977.4A
Authority: GB
Inventors: Gubbins Stephen
Original assignee: Luceco PLC
Current assignee: Luceco PLC
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2020-09-16
Anticipated expiration: 2040-02-13
Also published as: GB2582219B; GB202001977D0

Abstract

A wall-mountable electrical fitting includes a back-box 12 suitable for attachment to a wall 14, a front panel 24 and a screw connector 32 for removable connection of the front panel to the back box. The front panel includes a passage 30 through which the screw connector extends. The passage includes a screw-retaining collar 34 retained within the front panel. The screw-retaining collar has one or more protrusions (42, Fig 3) protruding radially inwardly so as to contact a shank of the screw connector, thereby maintaining an alignment of the screw connector with the screw receiving connection point of the back box, and preventing the screw from falling out of the front panel when disconnected from the back box. The collar may have a frusto-conical flange (38, Fig 2) at one end and a flat flange (36, Fig 2) held in place by a plate (40, Fig 2) at the other.

Description

Electrical Fitting

Field of the invention

The invention relates to electrical fittings. More particularly, the invention relates to electrical fittings having screw retainers for screws used to secure a wall-mounted electrical fitting.

Background to the invention

Wall-mounted electrical components such as switches or socket plates may be installed in the form of an assembly comprising a "back-box" that is secured to (often sunk into) a wall, and comprising a front plate such as a socket plate or switch plate that is mounted onto the wall-mounted back-box. In many cases the front plate has holes with mounting screws passing through the holes to engage a connection point such as a threaded receptacle formed in the back-box. Some products comprise an intermediary plate that is mounted onto the back-box and the intermediary plate can be decorated -e.g. as an "invisible" plate with wall-paper that matches that of the surrounding wall and with a transparent front plate that renders the intermediary plate nearly invisible, or as a "screwless" plate having a clip-on surface plate mounted onto the intermediary plate such that no fixtures are visible on outer surfaces.

A common feature of the front plates, or intermediary plates, is that these are relatively thin in relation to a screw that is used for mounting the front plate to the box behind. As such, it is sometimes possible that a screw misaligns, i.e. is "off axis", which makes it more difficult for the screw to properly engage the corresponding connection point or threaded receptacle in the wall-mounted box.

US 10,312,676 B1 discloses the use of a spacing member formed of a resilient material which the mounting screw is inserted through and which acts as a compressed resilient spacing member. However the mounting screws still need to be individually manually aligned with the connection points on the back-box.

The present invention has been conceived with the foregoing in mind.

Summary of the invention

In accordance with an aspect of the invention, there is provided a wall-mountable electrical fitting as defined in claim 1.

Embodiments of the invention are defined in the dependent claims.

The invention improves the ease with which an end of a screw connector is presented into the connection point (e.g. a threaded hole) of a back-box after being inserted through a front/intermediary plate. Embodiments of the invention provide a collar in the passage through which the screw is inserted. The collar is retained by the front panel and includes protrusions or indents that protrude radially inwardly and contact or grip the shank of the screw as it passes through, which ensures that the screw is presented perpendicular to front panel, and aligns with the receiving threaded holes in the back-box. Normally the screw would require lining up to the threaded hole by angling the product away from the wall. A further advantage is that when the front panel is removed from the back-box, the collar gripping the screw keeps it in place in the panel so that the screw will not fall out (and maybe get lost).

Brief description of the Drawings

Figure 1 shows a back-box and a front panel for mounting to the back box of a wall-mountable electrical fitting in accordance with embodiments of the invention Figure 2 is a cross-section through part of a front panel showing a mounting screw arrangement of the wall-mountable electrical fitting of Figure 1.

Figure 3 is an illustration of a screw-retaining collar of the mounting screw arrangement shown in Figure 2.

Detailed Description

Referring to Figure 1, an electrical fitting 10, such as an electrical socket or switch unit, comprises a back-box 12, which secured to a wall 14. The back-box 12 is typically formed of a suitable plastics material, such as urea or polycarbonate, or may be formed of a metal such as brass or steel. As shown the back-box 12 has an open front side and is mounted directly onto the surface of the wall 14 so as to extend outwardly from the wall. The back-box 12 may be mounted to the wall with suitable screw fasteners or the like (not shown). However, in many installations the back-box 12 would be set into the wall 1, with the front edges 106 of the back-box flush with, or only extending a short distance from the surface. The back-box 12 has a number (two are shown) of connection points 18 in the form of holes with female threads for receiving threaded screws. The back box 12 also has an opening 20 through which electrical wiring 22, for example wiring of a ring main or lighting circuit, enters the fitting 10.

The wall 14 may be any appropriate surface, and need not be a vertical wall. The wall 14 may be a brick wall, with or without a layer of plaster, or it may be such as a stud wall formed of plaster boards or other board materials. Alternatively the wall 14 may be a substantially horizontal surface, such as a work surface or desk top. Also, the back-box 12 may form part of a conduit or ducting for electrical circuitry and components.

The electrical fitting 10 also includes a front panel unit 24, on a rear side of which are mounted appropriate electrical components/circuitry within a suitable housing 26. The electrical wiring 22 connects to the components/circuitry via suitable connections 28 on the housing 26. The front panel is typically formed of a suitable plastics material, such as urea or polycarbonate, or may include a metal such as brass or steel. The front panel 24 includes has a corresponding number (again two being shown) of screw passages 30 through which mounting screws 32 are inserted. The screw passages 30 are located to align the mounting screws 30 with the connection points 18 in the back-box 12. Retained within each of the screw passages 30 of the front panel 24 is a retaining collar 34, further details of which are described below.

Referring to Figure 2, which shows more detail of one of the mounting screws 32 extending through its screw passage 30 and collar 34. The collar 34, which is typically formed of a metal, such as brass, steel or other suitable alloy, or could be produced in plastic. The collar 34 is sized to sit within the screw passage 30 and is shaped to be retained within the screw passage 30. In the shown embodiment the collar is retained by means of a frusto-conical flange 38, which seats against a corresponding surface of the front panel 24 and underlies a countersink head of the screw 32, and a flat flange 36 on the rear side, which rests against a rear surface of a plate 130 that attaches to the rear side of the front panel 24, such that the plate is trapped between the flange 126 and the. The collar 34 is assembled in the passage 30 by first inserting it into the passage 30 from the front side of the front panel without the plate 40 in position. The plate 40 is then inserted between the rear side of the front panel 24 and the flange 36 of the collar before being secured to the front panel 24.

The collar 34, which is shown in more detail in Figure 3, has a number (there are 3 in this embodiment) of indents or protrusions 42, which extend radially inwardly towards the axis of the collar 34. The protrusions 42 are formed in the collar, for example by pressing, resulting in dimples 44 visible on the outer surface of the collar 34. As shown in Figure 2, the protrusions 42 extend radially inwardly so as to contact the shank of the screw 32. Alternatively the protrusion could be formed by application or attachment to the collar 34 and could be formed of the same material as the collar 34 or a different material (such as a plastics material).

In use, with a back-box 12 secured to a wall, and the wiring 22 connected to the connection points 28 on the housing 26 on the rear of the front panel 24, the mounting screws 32 are inserted through the screw passages 30. The screws are contacted by the protrusions 42 in the collars 34, which ensures that the screws maintain alignment (i.e. stay essentially perpendicular to the front panel 24). The front panel 24 is then offered up to the back-box 102 and the ends of the screws 122, maintaining their alignment due to the collars 34, are aligned with the connection points 18 in the back-box. The front panel 24 is then secured to the back-box 12 by screwing the screws 32.

When the front panel 24 is subsequently removed from the back-box 12 by unscrewing the mounting screws 32, the screws are still contacted by the protrusions 42 in the collars 34 and will not drop out, even if the front panel is 24 is tilted forwards.

In some embodiments the protrusions 42 extend inwardly to a distance from an axis of the collar 34 that is less than a radius of the shank of the screw 32 -resulting in an "interference" fit. In such an embodiment insertion of the screw 32 causes deformation of the protrusions 42, which provides a stronger gripping of the screw by the collar. In such cases, if the interference fit is very small, then the deformation may be essentially elastic such that the protrusions will assume their original shape when the screw is completely removed. If the interference fit is larger, then the deformation of the protrusions 42 may result in a permanent, plastic deformation, and the screw 32 will need to be unscrewed all the way out of the collar if it is to be removed.

In the embodiments described above the electrical components are contained in a housing 26 attached to the rear side of the front panel 24. It will be appreciated that the electrical components could instead be attached to or separately mounted in the back-box 12, and that this will not alter the principles of this disclosure, which relate particularly to how the front panel 24 is mounted to the back-box 12.

Claims

CLAIMS: 1. A wall-mountable electrical fitting comprising: a back-box suitable for attachment to a wall; a front panel having a front side and a rear side; and a screw connector for removable connection of the front panel to the back box, wherein the back box has a connection point for receiving the screw connector, wherein the front panel includes a passage through which the screw connector extends from the front side to the rear side, and wherein the passage includes a screw-retaining collar retained within the front panel, the screw-retaining collar having one or more protrusions protruding radially inwardly so as to contact a shank of the screw connector, thereby maintaining an alignment of the screw connector with the screw-receiving connection point of the back box, and preventing the screw from falling out of the front panel when disconnected from the back box.
2. The electrical fitting of claim 1 wherein the screw-retaining collar is formed of a metal.
3. The electrical fitting of claim 1 wherein the screw-retaining collar is formed of a plastics material.
4. The electrical fitting of any preceding claim wherein the protrusions are formed of a plastics material.
5. The electrical fitting of any preceding claim wherein the protrusions extend inwardly to a distance from an axis of the collar that is less than a radius of the shank of screw connector such that a first insertion of screw connector causes deformation of the protrusions.
6. The electrical fitting of claim 5 wherein the deformation of the protrusions comprises a permanent, plastic deformation.
7. The electrical fitting of any preceding claim wherein the collar and the passage are each shaped to retain the collar in the passage.
8. The electrical fitting of claim 7, wherein the collar has a frusto-conical flange which seats against a corresponding surface of the front panel.
9. The electrical fitting of claim 8, wherein the frusto-conical flange underlies a countersink head of the connecting screw.
10. The electrical fitting of any of claims 7 to 9, wherein the collar has a flat flange which rests against an inner surface of a plate attached to the rear side of the front panel.
11. The electrical fitting of any preceding claim wherein the back box is part of a conduit or ducting for electrical circuitry and components.