GB2281450A - Earthing strap for a electrical assembly - Google Patents
Earthing strap for a electrical assembly Download PDFInfo
- Publication number
- GB2281450A GB2281450A GB9317886A GB9317886A GB2281450A GB 2281450 A GB2281450 A GB 2281450A GB 9317886 A GB9317886 A GB 9317886A GB 9317886 A GB9317886 A GB 9317886A GB 2281450 A GB2281450 A GB 2281450A
- Authority
- GB
- United Kingdom
- Prior art keywords
- hole
- face plate
- earthing
- electrical assembly
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R4/00—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation
- H01R4/58—Electrically-conductive connections between two or more conductive members in direct contact, i.e. touching one another; Means for effecting or maintaining such contact; Electrically-conductive connections having two or more spaced connecting locations for conductors and using contact members penetrating insulation characterised by the form or material of the contacting members
- H01R4/64—Connections between or with conductive parts having primarily a non-electric function, e.g. frame, casing, rail
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
- H01R13/648—Protective earth or shield arrangements on coupling devices, e.g. anti-static shielding
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R2103/00—Two poles
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
- H01R24/00—Two-part coupling devices, or either of their cooperating parts, characterised by their overall structure
- H01R24/76—Two-part coupling devices, or either of their cooperating parts, characterised by their overall structure with sockets, clips or analogous contacts and secured to apparatus or structure, e.g. to a wall
Abstract
An electrical assembly e.g. a socket, has a face plate 1 with at least one mounting hole 5 to receive a screw to secure the plate and an earthing strap 4 having an earthing contact surface 10 which is shaped to make direct contact with the screw 11 in use. In another embodiment, Figure 6, the strap 4 semi-circular tabs (33) surrounding the screw 11 with bevelled surfaces (34) which fit into the countersunk surface (5a) of the face plate 5. <IMAGE>
Description
ELECTRICAL COMPONENT WITH IMPROVED
EARTH BAR SECURING MEANS
The present invention relates to an electrical assembly with improved earthing strap securing means. The invention is particularly suitable for use with electrical assemblies such as switches, socket outlets (TV, telephone, shaver, computer), connection units, cable outlets, cooker control units, trailing sockets etc.
Where an electrical component is to be mounted to a wall or other surface using mounting screws, it is desirable that the exposed mounting screws of the electrical assembly be earthed. In a known assembly, the earthing strap is provided with holes which are aligned with corresponding mounting holes in the face plate of the assembly. The earthing strap is secured to the face plate by electrically conducting eyelets which extend through the holes in the face plate and the earthing strap, each eyelet being swaged over to secure the strap to the face plate. When the assembly is mounted in position on another member such as a wall, a screw is passed through each eyelet and the head of the screw makes contact with the eyelet thereby making electrical contact with the earthing strap. The earthing strap is provided with a terminal for coupling it to the earth wire of the electrical power distribution network.
According to the present invention there is provided an electrical assembly comprising a face plate with at least one mounting hole therein to receive a mounting screw to attach the assembly to a mounting member, a body secured to the face plate, and an earthing strap having an integral earthing contact surface which is shaped to engage, in use, directly with the mounting screw to make electrical contact therewith and earth the assembly.
In one embodiment of the invention, the body has at least one mounting hole formed therein which is aligned with the or each face plate hole, the earthing strap having a first portion extending between the body and the face plate and a second portion overlying the body, said first and second portions having a hole therein aligned with a respective mounting hole in the body to receive the assembly mounting screw when fitted in the or each hole in the earthing strap and the body. In this embodiment, the first portion of the earthing strap preferably has a bevelled countersunk surface around its periphery which projects towards the second earthing strap portion to provide said earthing strap contact which, in use, cooperates with a correspondingly bevelled surface on a mounting screw to make said electrical contact to earth the assembly.
Preferably, the body has a flange located above but spaced from the or each hole in the face plate, said flange having a hole therein and the earthing strap fitting around said flange with the first portion thereof located under said flange.
In an alternative embodiment, the earthing strap has a pair of laterally deflectable tabs which locate in the or each hole in the face plate, each of said tabs having a bevelled surface thereon to provide said integral earthing contact surface which engages, in use, with a mounting screw.
In this embodiment, the earthing strap preferably has a hole therein located above the hole in the face plate, the tabs extending downwardly from opposite edges of the earthing strap adjacent said hole. Preferably the tabs are arcuate in cross section so that together they provide a substantial cylindrical section which extends from the earthing strap normal thereto. Preferably the bevelled surface is provided at the free end of each tab.
The earthing strap is preferably made of a resilient electrically conductive material such as phosphor bronze, the resilience of the material allowing the tabs to move towards each other during installation to make a snap fit in the face plate mounting hole. The earthing strap can however be made of any suitable electrically conductive material
Preferably the or each hole in the face plate has an initial portion of a diameter larger than the head of the mounting screw and a second portion of progressively reducing diameter to provide a countersunk surface in the face plate.
The main advantage of the electrical assembly of the present invention is that it facilitates the manufacturing process and reduces the cost of manufacture as it omits the eyelet used in prior art assemblies to attach the earthing strap to the face plate. Thus, component material can be saved and a costly manufacturing step can be avoided.
A further advantage of the present invention is that the electrical assembly can be readily dismantled for repair as the earthing strap is not permanently secured to the face plate. With the prior art arrangement, to achieve this would involve drilling out the swaged over end of the eyelet which secures the earthing strap to the face plate.
Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a front view of a twin 13 amp socket assembly according to the present invention;
Figure 2 is a partial perspective view of a prior art earthing strap mounting arrangement;
Figure 3 is a rear view of the socket assembly shown in
Figure 1;
Figure 4 is a sectional view along the line A-A' in
Figure 3 showing the socket assembly mounted in position in a wall cavity;
Figure 5 is a perspective view partially in cross section of the earthing strap mounting arrangement shown in Figure 4; and
Figure 6 is a perspective view, partially in section, of an alternative earthing strap mounting arrangement.
Referring first to Figure 2, there is shown a prior art electrical assembly which comprises a face plate 1 to which a body housing the electrical components (not shown) is attached. An earthing strap 4 fits over the body and is attached to the face plate 1 by means of a phosphor bronze eyelet 15 fitted in each mounting hole 5 in the face plate, this mounting hole receiving a mounting screw 11. The inner edge of each mounting eyelet 15 is swaged over as illustrated to attach the foot 4a of the earthing strap 4 to the face plate 1.
Referring now to Figures 1 and 3, there is shown a twin 13 amp main socket assembly comprising a molded plastic face plate 1 and a body 2 secured thereto which houses all the electrical components of the switch assembly.
Screws 3 secure the body 2 to the face plate 1. An earthing strap 4 extends over the body 2 and is provided at each end with holes which overlie mounting holes 5 in the face plate 1. The body 2 includes socket openings 12 to receive the pins of a 13 amp plug and switching mechanisms 13. With the exception of the earthing strap mounting arrangement to be described in more detail hereafter, the socket shown in Figures 1 and 2 is of entirely conventional design.
Referring now to Figures 3-5, there is shown a preferred earth strap mounting arrangement in accordance with the present invention. The body 2 is provided with a laterally extending flange 6 which extends across the mounting hole 5 but is spaced therefrom by a gap 17. The flange 6 is itself provided with a through hole 7 aligned with the mounting hole 5.
The earthing strap 4, which extends across the body 2 as shown in Figure 3, follows the contour of the body 2 around the flange portion 6 and terminates beneath it.
Thus, end portion 8 of the earthing strap 4 comprises a first portion 16 which extends across the hole 7 in the flange 6 and a return 16a which passes between the hole 7 in the body 2 and the mounting hole 5 in the face plate 1. Holes 9 and 10 are provided in the earthing strap 4 on either side of the flange 6 and generally in alignment with the hole 7 in the body 2.
The periphery of the hole 10 includes a bevelled countersunk surface 18 around its periphery which projects towards the first portion 16 of the earthing strap 4. This provides the electrical contact surface for engagement with bevelled head surface 19 on mounting screw 11. To ensure proper seating of the surface 19 on the mounting screw 11 against the countersunk contact surface 18 on the earthing strap 4, the mounting hole 5 in the face plate 1 is provided with a countersunk surface 5a of a reducing diameter compared with that of the rest of the hole 5.
Figure 4 shows the way in which the electrical assembly shown in Figure 3 is mounted in position in a mounting box 20 located in a hole 24 in a wall 22 and secured therein by means of screws 25. The mounting box includes inwardly directed tabs 21 which are threaded to receive mounting screw 11. It will be seen therefore that as each mounting screw 11 is tightened (only one is shown), it draws the face plate 1 against front surface 26 of the wall 22.
The earthing strap 4 shown in the arrangements of
Figures 3-5 is assembled under the body flange 6 by flexing the end portion 8 to fit under it.
Figure 6 shows an alternative mounting strap 4 provided with a foot portion 30 from which a web 31 extends laterally to overlie hole 5 in the face plate 1. A hole 32 is formed in the web 31 and semi-circular tabs 33 project downwardly from the outer edges of the web adjacent the hole 32. The free ends of the tabs 33 are provided with an outwardly directed bevelled surface 34 which is adapted to fit into correspondingly formed countersunk surface 5a in the hole 5 in the face plate 1. A tapered hole 37 is formed in the base 2 and it can be seen that when the base 2 is fitted onto the face plate 1 a venturi shaped hole 37,5a,5 is formed therethrough for reasons which will be explained shortly.
The earthing strap 4 is preferably made of a phosphor bronze material which is stamped out in the flat and then subsequently formed into the configuration illustrated. A space 35 is provided between the facing ends of the tabs 33 and this allows the tabs to be flexed inwardly towards each other to enable the countersunk surfaces 34 at their free ends to pass through the narrowest point in the hole 37,5a,5 which extends through the face plate 1 and the base 2 mounted thereon. This enables the tabs 33 to be snap-fitted into position in the hole 37,5a,5 with their bevelled surface 34 engaging with the countersunk surface 5a in the face plate hole 5. The mounting screw 11 can then be fed through the cylindrical section formed by the facing tabs 33, through the hole 32 in the earthing strap 4 and into engagement with suitable mounting means (not shown) on the mounting member (not shown) to which the electrical assembly is to be fitted.
It will be seen from the foregoing description that the
Figure 6 embodiment provides a simple to manufacture earthing strap which can be readily fitted to the electrical assembly by making a snap-fit therewith.
Thus, the need for connecting eyelets of the prior art is avoided. Also, the earthing strap 4 can be fitted to the electrical assembly without the need for special tools thereby saving expensive manufacturing assembly costs.
Claims (11)
1. An electrical assembly comprising a face plate with at least one mounting hole therein to receive a mounting screw to attach the assembly to a mounting member, a body secured to the face plate, and an earthing strap having an integral earthing contact surface which is shaped to engage in use, directly with the mounting screw to make electrical contact therewith and earth the assembly.
2. An electrical assembly as claimed in claim 1 wherein the body has at least one mounting hole therein aligned with the or each face plate hole, the earthing strap having a first portion extending between the body and the face plate and a second portion overlying the body, said first and second portions having a hole therein aligned with a respective mounting hole in the body to receive the assembly mounting screw when fitted in the or each hole in the earth strap and the body.
3. An electrical assembly as claimed in claim 2 wherein the hole in the first portion of the earthing strap has a bevelled countersunk surface around its periphery projecting towards the second earthing strap portion, said countersunk surface, in use, cooperating with a correspondingly bevelled surface on a mounting screw to make said electrical contact and earth the assembly.
4. An electrical assembly as claimed in claim 3 wherein the body has a flange located above but spaced from the or each hole in the face plate, said flange having a hole therein and the earthing strap fitting around said flange with the first portion thereof located under the flange.
5. An electrical assembly as claimed in claim 1 wherein the earthing strap has a pair of laterally deflectable tabs which locate in the or each hole in the face plate, each of said tabs having a bevelled surface thereon to provide said integral earthing contact surface which engages with the mounting screw.
6. An electrical assembly as claimed in claim 5 wherein the earthing strap has a hole therein located over the hole in the face plate, the tabs extending downwardly from opposite edges of the earthing strap adjacent said hole.
7. An electrical assembly as claimed in claim 5 or claim 6 wherein the tabs are arcuate in cross section, said tabs together providing a substantial cylindrical section which extends from the earthing strap normal thereto.
8. An electrical assembly as claimed in any of claims 5-7 wherein the bevelled surface is provided at the free end of each tab.
9. An electrical assembly as claimed in any of claims 5-8 wherein the tabs make a snap-fit in the face plate mounting hole.
10. An electrical assembly as claimed in any preceding claim wherein the or each hole in the face plate has an initial portion of a larger diameter than the head of a mounting screw and a second portion of progressively reducing diameter to provide a countersunk surface.
11. An electrical assembly, substantially as herein described with reference to the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9317886A GB2281450B (en) | 1993-08-27 | 1993-08-27 | Electrical component with improved earth bar securing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9317886A GB2281450B (en) | 1993-08-27 | 1993-08-27 | Electrical component with improved earth bar securing method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9317886D0 GB9317886D0 (en) | 1993-10-13 |
| GB2281450A true GB2281450A (en) | 1995-03-01 |
| GB2281450B GB2281450B (en) | 1997-08-13 |
Family
ID=10741164
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9317886A Expired - Fee Related GB2281450B (en) | 1993-08-27 | 1993-08-27 | Electrical component with improved earth bar securing method |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2281450B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2852153A1 (en) * | 2003-03-03 | 2004-09-10 | Legrand Sa | Electrical installation e.g. interrupter for e.g. wire duct support, has metallic grip fastening buckle with free ends engaged in orifices of hub cap plate, where ends have locking system co-operating with orifices locking system |
| GB2399956B (en) * | 2003-03-03 | 2006-09-13 | Legrand Sa | Electrical device with metal earthing strip |
| GB2570148A (en) * | 2018-01-12 | 2019-07-17 | Focus Sb Ltd | An electrical fitting |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB661611A (en) * | 1949-05-11 | 1951-11-21 | George H Scholes & Company Ltd | Improvements relating to three pin socket electrical connectors |
| GB956964A (en) * | 1960-01-08 | 1964-04-29 | Ashley Accessories Ltd | Improvements in or relating to boxes for electrical accessories |
| GB956963A (en) * | 1959-07-17 | 1964-04-29 | Ashley Accessories Ltd | Improvements in or relating to earthing devices for electrical accessories, appliances and apparatus |
| GB2247575A (en) * | 1990-08-07 | 1992-03-04 | Daiichi Denso Buhin | Conducting earth continuity connection device. |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2816800B2 (en) * | 1993-08-18 | 1998-10-27 | 第一電装部品株式会社 | Conductive connection device |
-
1993
- 1993-08-27 GB GB9317886A patent/GB2281450B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB661611A (en) * | 1949-05-11 | 1951-11-21 | George H Scholes & Company Ltd | Improvements relating to three pin socket electrical connectors |
| GB956963A (en) * | 1959-07-17 | 1964-04-29 | Ashley Accessories Ltd | Improvements in or relating to earthing devices for electrical accessories, appliances and apparatus |
| GB956964A (en) * | 1960-01-08 | 1964-04-29 | Ashley Accessories Ltd | Improvements in or relating to boxes for electrical accessories |
| GB2247575A (en) * | 1990-08-07 | 1992-03-04 | Daiichi Denso Buhin | Conducting earth continuity connection device. |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2852153A1 (en) * | 2003-03-03 | 2004-09-10 | Legrand Sa | Electrical installation e.g. interrupter for e.g. wire duct support, has metallic grip fastening buckle with free ends engaged in orifices of hub cap plate, where ends have locking system co-operating with orifices locking system |
| GB2400502A (en) * | 2003-03-03 | 2004-10-13 | Legrand Sa | Electrical device with clip-on earth connection metal strip |
| GB2400502B (en) * | 2003-03-03 | 2006-01-04 | Legrand Sa | Electrical device with earth connection metal strip |
| GB2399956B (en) * | 2003-03-03 | 2006-09-13 | Legrand Sa | Electrical device with metal earthing strip |
| CN100486402C (en) * | 2003-03-03 | 2009-05-06 | 罗格朗法国公司 | Electric appliance with metal grounding connecting plate |
| GB2570148A (en) * | 2018-01-12 | 2019-07-17 | Focus Sb Ltd | An electrical fitting |
| GB2570148B (en) * | 2018-01-12 | 2022-09-14 | Focus Sb Ltd | An electrical fitting |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9317886D0 (en) | 1993-10-13 |
| GB2281450B (en) | 1997-08-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20070827 |