GB2403347A

GB2403347A - Electrical component assemblies

Info

Publication number: GB2403347A
Application number: GB0314973A
Authority: GB
Inventors: Christopher Wade
Original assignee: Hager Engineering Ltd
Current assignee: Hager Engineering Ltd
Priority date: 2003-06-26
Filing date: 2003-06-26
Publication date: 2004-12-29
Anticipated expiration: 2023-06-26
Also published as: GB0314973D0; GB2403347B

Abstract

An electrical accessory, for example an electrical switch, comprises a front plate 2, a housing 6 attachable to the front plate, a rocker assembly 4 locatable in the front plate, a number of electrical contacts and terminals locatable in the housing, and at least one movable electrical contact 16. The movable electrical contact 16 is locatable in the front plate and movable by movement of the rocker assembly to contact the one or more electrical contacts located in the housing.

Description

Electrical component Assemblies The present invention relates to

electrical component assemblies and more particularly to mounting electrical accessories in a support plate.

Background of the Invention

Electrical wiring accessories such as switches and sockets typically comprise plates of metal or plastics material which are attachable to a wall or other supporting structure and which support the circuit elements of the accessory, the circuit elements being attached to the back of the plate and being accommodated in either a box or an aperture in the wall behind the plate.

The components of the accessory which accommodate the working parts behind the plate may be integral with the plate or attached to the plate by screws, rivets or the like.

Conventional electrical wiring accessories may be mounted singly or as multiple units on a single face plate. Many configurations of such accessories are possible which results in the need for a manufacturer to provide a wide range of accessories leading to high manufacturing costs.

In British Patent No. 2,194,395 there is described a means whereby a single supporting plate may support a variety of interchangeable electrical accessories of different types, so that the type of accessory installed may be varied at will, but once installed in the plate, the accessory cannot readily be removed from the plate without removing the plate from the box or surface on which it is mounted. The accessory is mounted from the front of the supporting plate.

British Patent No. 2,274,218 describes an electrical component assembly in which the supporting plate may support a variety of interchangeable electrical accessories of different types, the accessories being mountable in the supporting plate from the front or back of the plate.

British Patent Application 2,376,798 is directed to an electrical switch having a rocker for operating the switch, the rocker being pivotally mounted to a body.

The body has a rear facing surface for abutting a front facing surface of a front plate. The electrical switch is described as being mounted to the front plate and inserted therein from the front of the plate.

Summarv of the Invention The present invention provides an electrical assembly comprising a front plate; a housing attachable to the front plate; a rocker assembly locatable in the front plate; a number of electrical contacts and terminals locatable in the housing; and at least one movable electrical contact locatable in the front plate and being movable by movement of the rocker assembly to contact in use the one or more electrical contacts located in the housing.

Preferably, the electrical accessory comprises an electrical switch or a plurality of electrical switches mounted in the front plate.

Preferably, said accessory comprises three terminals locatable in the housing and two fixed electrical contacts locatable in the housing.

In a preferred embodiment the electrical accessory further comprises a number of deformable lugs connected to one or other of the housing and the front plate to retain the housing on the front plate.

Preferably, the housing is a one-piece unit.

In a preferred embodiment, the movable electrical contact is locatable on a projection extending from one of the terminals locatable in the housing, said projection projecting through the front plate in the assembled configuration to act as a pivot for the movable electrical contact.

Preferably the rocker assembly is arranged to be retainable in the front plate but pivotal with respect to the housing, said rocker assembly being locatable in channels in the housing.

The electrical accessory embodying the present invention aims to provide an inexpensive switch assembly which is quick and easy to assemble and one which is simple in construction, thereby reducing manufacturing and installation costs.

Brief Description of the Drawings

The present invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a front elevation of a switch assembly according to the invention; Figure 2 is a side elevation of a switch assembly according to Figure 1; Figure 3 is a rear elevation of the switch assembly of Figure 1; Figure 4 is a section through the switch assembly of Figure 2 in side elevation along the line A-A; Figure 5 is a section through the switch assembly of Figure 2 in side elevation along the line B-B; Figure 6 is a perspective view of the rear of the switch assembly of Figure 1; Figure 7 is a plan view of the internal mechanism of the switch assembly of Figure 2 with the front cover, moving contact, plunger, spring and rocker assembly removed; Figure 8 is an elevation of the switch assembly of Figure 1 showing the plate fixing mechanism with the rocker, plunger and spring removed; Figure 9 is an elevation of the rear of the rocker of the switch assembly of Figure 1 showing the spring fixing; Figure 10 is a front view of an embodiment of a double rocker switch according to the invention; Figure 11 is a rear elevation of the switch assembly of Figure 10; and Figure 12 is a section of the switch assembly of Figure 11 in side elevation along the line B-B.

Detailed Description of The Preferred Embodiments

Referring to Figures 1 to 9, the switch accessory 1 comprises a front plate 2, of, for example, generally square or rectangular shape, having a substantially rectangular aperture therein. The front plate 2 has fixing holes 3 for the introduction of screws or bolts for mounting the switch accessory 1 to a surface in the usual way. The switch accessory 1 also comprises a switch assembly 4 which includes a housing 6, a rocker 8, a plunger 10, a spring 12 and a plurality of terminals 13, 14, 15 (preferably three terminals), each with associated contacts 16, 17 and 18. The housing 6 houses the terminals 13, 14, 15 for connecting external wiring to the switch assembly 4. The first terminal 13 has a movable contact 16 and the second and third terminals 14 and 15 each have a fixed contact 17, 18. The housing 6 houses the associated fixed contacts 17 and 18. The first terminal 13 comprises a projection 19 which extends, in the assembled configuration, through the aperture in the front plate 2. The projection 19 provides electrical contact to the movable contact 16 as well as support thereto and acts as a pivot about which the movable contact 16 may move.

The housing 6 has a number of holes therethrough for providing access to the terminals 13, 14, 15 through which wires can be introduced and secured by means of, for example, a set screw 20. Each terminal 13, 14, 15 has one set screw 20 to hold the connecting wires in position in the terminal.

The rocker 8 may be formed of non-conducting material, such as a plastics material, and it extends through the aperture in the front plate 2 of the switch accessory 1 in the assembled configuration. The rocker 8 is pivotally mounted on the housing 6 and activates the switch assembly 4 contained in the housing 6. The plunger 10 is located and retained in the bore of a substantially centrally located tubular portion 22 projecting outwardly from the undersurface of the rocker 8.

The rocker 8 has two ribs 24, 26 (one of which is shown in Figure 5 and both of which are shown in Figure 9) which extend radially from the tubular portion 22 housing the plunger 10. The ribs 24, 26 act as pivots, and are mountable in channels 29 in two members 30 that project forwards from the inner face of the housing 6. In the assembled configuration, the members 30 are located on either side of the switch assembly 4, and extend through the aperture in the front plate 2 in which the rocker 8 is locatable.

The housing 6 clips to the front plate 2 in four places (two of which are shown in Figure 5) by means of deformable lugs 34, 36 insertable into apertures in the front plate 2. The deformable lugs 34, 36 locate on four ridges 38 in the walls defining the apertures in the front plate 2.

Retaining screws 42 are used to mount the front plate 2 to, for example, a wall in use, as shown in Figure 6. The retaining screws extend through the apertures 3 in the front plate 2. The retaining screws 42 extend through the apertures 3 in the front plate 2 in the assembled configuration to retain the front plate 2 in position on a wall in use.

The internal mechanism of the switch assembly is shown in Figure 7. The two fixed contact assemblies comprising the second and third terminals 14, 15 and the two fixed contacts 17, 18 associated therewith are assembled into the housing 6 together with the common contact assembly comprising the first terminal 14 and the movable contact 16. The fixed contact assemblies are located in the housing 6 by three ribs, one rib 44 located on either side of the respective fixed contact 17, 18 and one rib 46 located at the end of each of the contact assemblies adjacent the common contact assembly.

The housing 6 has two bosses 47 projecting from the mounting face to the front plate 2, adjacent the deformable lugs 34, 36. The front plate 2 has two similar bosses (not shown) on t he corresponding m ounting f ace, b ut in the opposite side ofthe movable contact16 in the assembled configuration so that when the housing 6 is offered up to the front plate 2 for assembly, it may be pressed home if the orientation be correct, but should the housing 6 be rotated 180 degrees in the p lane o f t he front plate 2, the b osses 4 7 w ould interfere and prevent assembly. This assists correct assembly of the accessory 1.

As shown in Figure 8, the moveable contact 16 is located in the aperture in the front plate 2 into which the rocker 8 is inserted in use. Two projections 48 which extend one from either side of the movable contact 16 midway locate in between four projections 49 from the side walls of the aperture and the main portion of the contact 16 rests in a channel formed by the four projections 49.

As shown in Figure 9, the spring 12 is mounted in the in the bore of the tubular portion 22 projecting outwardly from the undersurface of the rocker 8.

The spring 12 is held in position by a triangular rib 50 and three lugs 52 extending from the base of the tubular portion 22 adjacent the undersurface of the rocker 8. The plunger 10 has a diameter larger than that of the internal diameter of the spring 12 and is gripped in the end of the spring 12. Two deformable fixing ribs 54 extend one from each side of the rocker 8 and are locatable on the side walls of the aperture in the front plate 2 to hold the rocker 8 in the front plate 2 in the assembled configuration, as shown in Figure 9.

In the single switch assembly of Figures 1 to 9, the switch assembly 4 is mounted on the front plate 2 with the co-operating rocker 8 inserted from the front, through the aperture in the front plate 2 where it is retained by the two deformable fixing ribs 54.

The spring loaded plunger 10 in the rocker 8 presses on the movable contact 16 which is shaped in a slight curve and the movable contact 16 pivots about the projection 19 projecting from the edge of the first terminal 14. As the rocker 8 is operated so the point of contact of the plunger 10 on the movable contact 16 moves across the pivot point thereby tilting the movable contact 16 to make contact with the appropriate fixed contact 17, 18.

To assemble the switch, the terminals 13, 14 and 15 and the two fixed contacts 17,18 are placed in position in the housing 6. The movable contact 16 is laid in place in the aperture in the front plate 2. The rocker 8 is inserted into the aperture in the front plate 2 and pushed home until the deformable fixing ribs 54 engage with the side walls of the aperture. The housing 6 is then positioned so that the deformable lugs 34, 36 locate on the four ridges 38 in the walls defining the apertures in the front plate 2. The housing 6 is then pressed onto thefront plate 2 until the four deformable lugs 34,36 engage with the ridges 38 on the front plate 2.

Figures 10 to 12 show a further embodiment of a switch assembly according to the present invention. The switch assembly shown in these figures includes two switches 4, 4' of the type described above in connection with Figures 1 to 9 having two rocker assemblies 8, 8' mounted in a single face plate 56.

The assembly and operation of the double-switch accessory shown in Figures 10 to 12 is identical to that described above with respect to Figures 1 to 9. If desired, more than two switch assemblies could be mounted in a single face plate.

Various alternatives to the assembly described above are possible, for example, the switches illustrated in Figures 1 to 12 are single-pole twoway switches (also known as change-over switches). However, by omitting one of the fixed contacts, the switches could be used as single pole oneway switches.

Also, in the assembly of the switch accessories 1, 10, the housing 6 containing the terminals 13, 14, 15 and the fixed contacts 17, 18 may be attached to the front plate 2 prior to attachment of the movable contact 16 and rocker 8.

The invention provides a versatile system for mounting an electrical assembly on or in a support plate. The switch accessories embodying the invention are quick and easy to assemble without the need for use of rivets or screws in the assembly of the switch accessories and are comprised of a few parts. which provides flexibility and allows a single accessory body construction to be used in a variety of situations.

Claims

Claims 1. An electrical accessory comprising: a front plate; a housing

attachable to the front plate; a rocker assembly locatable in the front plate; a number of electrical contacts and terminals locatable in the housing; and at least one movable electrical contact locatable in the front plate and being movable by movement of the rocker assembly to contact in use the one or more electrical contacts located in the housing.
2. An electrical accessory according to Claim 1, wherein the electrical accessory comprises an electrical switch.
3. An electrical accessory according to Claim 1, comprising a plurality of electrical switches mounted in the front plate.
4. An electrical accessory according to any one of the preceding claims, wherein said accessory comprises three terminals locatable in the housing and two fixed electrical contacts locatable in the housing.
5. An electrical accessory according to any one of the preceding claims, further comprising a number of deformable lugs connected to one or other of the housing and the front plate to retain the housing on the front plate.
6. An electrical accessory according to any one of the preceding claims, wherein the housing is a one-piece unit.
7. An electrical accessory according to any one of the preceding claims, wherein the movable electrical contact is locatable on a projection extending from one of the terminals locatable in the housing, said projection projecting through the front plate in the assembled configuration to act as a pivot for the movable electrical contact.
8. An electrical accessory according to any one of the preceding claims, wherein the rocker assembly is arranged to be retainable in the front plate but pivotal with respect to the housing, said rocker assembly being locatable in channels in the housing.
9. An electrical accessory substantially as hereinbefore described with reference to any one embodiment as that embodiment is depicted in the accompanying drawings.