GB2290663A

GB2290663A - An electrical switch

Info

Publication number: GB2290663A
Application number: GB9512411A
Authority: GB
Inventors: David Sydney Mahoney
Original assignee: Caradon MK Electric Ltd
Current assignee: Caradon MK Electric Ltd
Priority date: 1994-06-20
Filing date: 1995-06-19
Publication date: 1996-01-03
Anticipated expiration: 2015-06-19
Also published as: GB9412325D0; GB2290663B; GB9512411D0

Abstract

A rocker operated electrical switch 1 comprises a rocker 2, a surround e.g. a frontplate 3 and a housing 4. The rocker 2 comprises an outer part 10 and an inner part 12. The inner part 12 is of a contrasting appearance to the outer part 10. An indication of when the switch is in one state is provided by the inner part 12 extending through an aperture 5 in the surrounding frontplate 3. In another state the inner part 12 is shielded by the surrounding frontplate 3. <IMAGE>

Description

Improvements to an electrical switch The present invention relates to an electrical switch which is rocker operated.

Electrical accessories such as socket outlets and connection units conventionally include a switch to disconnect the electrical supply from the load, without in the case of socket outlets having to remove the plug from the socket, or in the case of connection units having to remove the fuse link. In order for the user to know whether the electrical power is disconnected or not, an end of the rocker that is visible when in the 'ON' position is painted or printed red. The rocker is frequently made of a material with a high resistance to scratching, such as a thermosetting plastics material.

These materials with high scratch resistance tend to have an impervious surface which is resistant to attack from chemicals, such a surface being a poor substrate for applying inks or paints. Hence the red indication is often difficult to apply permanently to the rocker and when applied may easily be scraped off in the course of normal operation over a number of years. Various attempts at improving the permanence of the indication have been tried and include ensuring that the mould tool has either a rough surface or a grooved surface extending over the area required for the application of the indication.This is difficult to achieve as the end surface of the rocker is normally substantially perpendicular to the split line of the moulding tool, hence it is parallel to the direction in which the moulding will be ejected from the tool, which restricts the degree of roughness or the type of grooves that can be applied to the end to the rocker.

According to the present invention a rocker operated electrical switch comprises a rocker, a switch housing, and a surround for the housing having an aperture therein, the rocker extending through the aperture, the rocker being mounted for rocking movement between at least two positions, the rocker having an outer part arranged for digital manipulation fixed to an inner part for actuating a switch contact, the inner part having a contrasting appearance to the outer part, characterised in that the inner part extends through the aperture in one said rocker position so as to be visible and in that the inner part is shielded by the surround in another said rocker position.

Preferably the inner part is made from a differently coloured material to that of the outer part.

The inner part may also be of a different surface texture at the point where it is visible to that of the outer part.

A benefit of having the rocker formed from two parts according to the present invention is that permanent means are provided for the indication of the 'ON' state of the switch, by the colour and or texture of the inner part contrasting with the surrounding material of the digitally operable part of the rocker. The production process is simplified as the colour of the inner part is determined by the moulding material rather than by the amount or thickness of paint or ink that is applied in the existing process. A further benefit is that the assembly of the two components is an operation that is easy to automate, whereas in a painting process it is necessary to both apply heat and allow time to ensure that the paint is dry.Where the range of switches includes a variety of different colours for the rockers, it is very difficult to achieve consistency in the colour of the indication when this is done by the application of paint or ink. It may even be necessary to have a two stage painting process, where an undercoat of a white paint is applied first and then this is covered with the coloured paint. Whereas with a two part rocker the consistency of the colour of the indication is only dependent on the colour of the inner part.

The inner and outer parts may be of completely different materials, such as the outer part being made of metal and the inner part being made of a thermoplastics material.

The advantage of using different materials for the inner and outer parts is that not only can the desired benefit of providing permanent indication of the 'ON' state of the rocker be achieved, but also materials that are best suited to the different operating requirements of the two parts may be chosen. For the outer part it is necessary to select a material with a high resistance to scratching and marking arising from contamination in use, while for the inner part it is necessary to choose a material that will facilitate the moulding of the intricate detail required to meet the design parameters.

Hence a material such a thermosetting plastics material or metal may be used for the outer part of the rocker while a contrasting thermoplastics material may be used for the inner part.

Preferably the inner part is formed of an electrically insulating material. This is advantageous in achieving an economic design of switch, whereby a part has several functions, such as providing locations for the plunger springs and providing the functional electrical insulation between the said plunger springs and a decorative metal outer part.

Preferably the inner part extends only partially across the width of the outer part at one end where it is visible in the said one rocker position. This facilitates the alignment of the inner and outer parts of the rocker, and ensures a close fit between the parts where they are both visible.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a cross section of a rocker operated electrical switch, forming part of an electrical wiring accessory, according to a first embodiment of the invention with the switch in an 'ON' position, and Figure 2 is a the same cross section as Figure 1, but with the switch in an 'OFF' position, and Figure 3 is a orthogonal view showing the top end of the rocker in Figure 1.

The switch mechanism shown in Figures 1 and 2 is part of an electrical accessory such as a socket outlet, a connection unit, a plate switch, or some other electrical accessory wherein it is advantageous to have an unmistakable indication of when the switch is in the 'ON' state.

A switch 1 comprises a rocker 2 which is movably located between a frontplate 3 acting as a surround and a moulded housing 4. The rocker 2 is arranged to protrude through an aperture 5 in the surrounding frontplate 3 so that it may be operated by digital manipulation.

Frontplate 3 has a rear face 7, and a top edge 8.

The rocker 2 comprises an outer part 10 and an inner part 12. The outer part 10 is retained on the inner part by means of three resilient latches 14 (only two shown) which upstand adjacent to the periphery of the inner part and engage in corresponding recesses 15 (only one shown) in the outer part. The rocker further comprises an extension 30 formed as part of the inner part 12, which has a recess 32 which locates a plunger 34. Plunger 34 is resiliently urged to protrude from the extension 30 by a spring 36. Plunger 38 has two ends 38, one of which acts against a moving contact 20.

The two ends 38 are identical, and shaped so that they each posses a shoulder 37 for locating the spring 36 and a radiused end 39 for acting against the moving contact 20.

The rocker is arranged to pivot about an axis 6. Fig. 1 shows the moving contact 20 in an ON state where it is in electrical contact with the fixed contact 22, and Fig. 2 shows the moving contact 20 in an OFF state where it is separated from the fixed contact 22.

The inner part 12 of the rocker protrudes the outer part 10 at one end 40, and is arranged to fit closely with the outer part at the joint line 44 of the abutting surfaces which extends around the periphery of the inner and outer parts. In Fig. 1 the end 40 is visible when viewed in a direction A. Fig. 2 shows that when the rocker is in a position corresponding to the OFF state the end 40 is shielded from view by the surrounding aperture edge 42.

From Fig. 3 showing the end view of the rocker it may be seen that there is a slight taper D to the joint lines 46 and 48 of the abutting surfaces of the inner and outer parts where the inner part is visible. This is to ensure that there is no gap between the inner and outer parts which could act as a dirt trap and detract from the appearance of the rocker. The taper D also enables the abutting surfaces to provide an accurate location between the inner and outer parts. To facilitate this it is necessary that the inner part 12 only extends over part of the width of the visible end face of the rocker, this is at the end 40 where the rocker protrudes the outer part 10. The joint line 50 is curved to bring it below the front surface 52 of the frontplate 3 when the switch is in the ON state shown in Fig. 1.This ensures that when the switch is in the ON state the visible end of the inner part is generally rectangular in shape.

From Fig. 2 it may also be seen that the joint line 54 is also arranged to be below the front surface 52 when the switch is in the OFF state. This is necessary to ensure that in normal operation when the switch is in the OFF state the inner part is completely shielded from view.

In use the switch 1 would normally be fitted with the rear face 7 against a mounting surface (not shown) so that the top edge 8 is mounted at the top of the electrical accessory. Hence in normal operation a user would look down to the accessory viewing it in the direction of arrow A.

The switch is operated by applying pressure to the outer part 10 of the rocker 2 in the direction of either arrow B to operate the switch to the OFF state or in the direction of arrow C to operate the switch to the ON state.

Since the inner part 12 of the rocker protrudes the outer part 10 at one end 40, when the rocker is in the ON state as shown in Fig. 1 the portion of the inner part comprising the end 40 is visible to the user. When the switch is in the OFF state as shown in Fig. 2 the end 40 is not visible being shielded by the aperture edge 42, hence no portion of the inner part is visible.

The inner part would normally be of a highly contrasting appearance to the outer part 10, and would preferably be of a different colour such as red, but could be of a contrasting texture, either as a result of different finishing to a moulding tool, or as a result of using different materials. This contrasting appearance provides a clear visible indication to the user of the state of the switch.

The degree of contrast that can be achieved by using this invention is far greater than that which can be achieved by applying paint of ink to the end of the rocker. Since the inner part is preferably moulded from coloured material the colour will be consistent throughout the cross-section of the inner part, hence should any wear take place by reason of the end 40 scraping against the aperture edge 42 or against any dirt or other foreign particle that may get trapped in the aperture 5, the contrasting appearance will not be lost or degraded. Further since provision of the inner part is often necessary to ensure ease of assembly and manufacture and or the required functional electrical insulation of the live parts such as the moving contact 20 and the fixed contact 22, there is a cost saving over methods that require paint or ink to be applied to the end 40 as a separate operation.

In another embodiment of the invention (not shown) the inner part of the rocker is made of a different material from the outer part, but which has a first level of contrast with the outer part until illuminated with a light source within the switch when it has a second level of contrast with the outer part. Preferably the first level of contrast is low and the second is high with respect to the outer part. It would be possible for the inner part to show one colour, for example green when illuminated with externally incident light, and a second colour say red when illuminated with an internal light source. The benefit of this is that both a normal state and an abnormal state of operation of the switch could be indicated to the user.

Claims

1. A rocker operated electrical switch comprising a rocker, a switch housing, and a surround for the housing having an aperture therein, the rocker extending through the aperture, the rocker being mounted for rocking movement between at least two positions, the rocker having an outer part arranged for digital manipulation fixed to an inner part for actuating a switch contact, the inner part having a contrasting appearance to the outer part, characterised in that the inner part extends through the aperture in one said rocker position so as to be visible and in that the inner part is shielded by the surround in another said rocker position.

2. A rocker operated electrical switch as claimed in claim 1 wherein the inner part is of a differently coloured material to that of the outer part.

3. A rocker operated electrical switch as claimed in claim 1 wherein the inner part is coloured red.

4. A rocker operated electrical switch as claimed in claim 1 wherein the inner part is formed of an electrically insulating material.

5. A rocker operated electrical switch as claimed in any one of claims 1 to 4 wherein the inner part extends only partially across the width of the outer part at one end where it is visible in the said one rocker position.

6. A rocker operated electrical switch substantially as described with reference to the accompanying drawings.