GB2180414A

GB2180414A - An electrical plug with branching circuit

Info

Publication number: GB2180414A
Application number: GB08621549A
Authority: GB
Inventors: James Macdonald Fursdon
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-09-12
Filing date: 1986-09-08
Publication date: 1987-03-25
Also published as: GB2180414B; GB8522586D0; GB8621549D0

Abstract

An electrical plug (2) comprising a body (4) having front and rear faces (10,12), at least two pins (14) projecting from the front face (10) of the body (4), at least two apertures (16) in the rear face (12) of the body (4), at least two connector devices (26) in the body for electrically connecting the pins with pins of another electrical plug that are pushed into the apertures, an electrical lead inlet aperture in the body (4), and terminal devices (30) for electrically connecting wires from the electrical lead to the pins projecting from the front face of the body, the plug being such that there are apertures in the rear face of the body corresponding in number to the pins projecting from the front face of the body whereby two or more of the plugs can be stacked together. The plug may include an on/off switch, an "on" illuminated indicator, and two fuses. <IMAGE>

Description

SPECIFICATION An electrical plug This invention relates to an electrical plug.

Electrical plugs are of course well known. In instances where it is desired to connect two electrical plugs to a single electrical socket, adaptors are used. As is well known, the adaptors comprise pins for insertion in the electrical socket and a body having two or more sets of apertures for receiving two or more plugs. The adaptors are relatively bulky items and, if they are left permanently in position, they can cause an unwanted obstruction, particularly on relatively restricted work surfaces in kitchens. Furthermore, the adaptors are relatively expensive items, costing more than the cost of a plug.

It is an aim of the present invention to provide an electrical plug which obviates the need for adaptors.

Accordingly, this invention provides an electrical plug comprising a body having front and rear faces, at least two pins projecting from the front face of the body, at least two apertures in the rear face of the body, at least two connector devices in the body for electrically connecting the pins with pins of another electrical plug that are pushed into the apertures, an electrical lead inlet aperture in the body, and terminal devices for electrically connecting wires from the electrical lead to the pins projecting from the front face of the body, the plug being such that there are apertures in the rear face of the body corresponding in number to the pins projecting from the front face of the body whereby two or more of the plugs can be stacked together.

The electrical plug of the present invention can be fitted into a socket, for example a wall socket. Alternatively, if desired, the electrical plug can be fitted to a trailing socket. Subsequently required plugs can then just be inserted into the apertures in the rear face of the body of the immediately preceding plug.

As many electrical plugs as may be desired may be stacked together, the only theoretical limit to the number of plugs stacked being that the total load from appliances connected to the plugs should not exceed the maximum for the particular wiring, for example 13 amps for domestic wiring. It will be obvious that there will be no need to employ adaptors.

With trailing sockets, there will also be no need to purchase the currently available and relatively costly multi-socket panels.

The plugs can be used to obtain multiple outlets from single socket points. The electrical plugs can of course also be used with double and treble sockets. They can be used to connect a multitude of domestic appliances, for example, mixers, coffee grinders, toasters, carving knives, televisions, videos, electrical games and lights in a simple and very convenient manner. Similarly, difficulties at computer terminals, with demands for many outlets, are equally elegantly overcome. The electrical plugs of the present invention may also be of considerable use in industry such for example as in retail shops, offices, laboratories and work shops where extra power points are often required and insufficient adaptors may be available. The electrical plug of the present invention avoids the need to buy extra adaptors and also avoids the need to install extra sockets.

In effect, the electrical plug of the present invention may be regarded as a self contained plug and adaptor. The stacked electrical plugs will normally occupy considerably less space than an adaptors or adaptors with the same number of currently known conventional plugs.

The stacked electrical plugs will look neater and will be considerably cheaper as mentioned above.

Usually, the electrical plug will be one in which the apertures in the rear face of the body are of the same shape as the cross sectional shape of the pins projecting from the front face of the body.

The pins projecting from the front face of the body will normally have a rectangular or a circular cross sectional shape. Obviously, if desired, other cross sectional shapes may be employed.

The electrical plug will usually be one in which there are two or three pins projecting from the front face of the body.

The apertures in the rear face of the body are preferably in line with the pins projecting from the front face of the body. If desired, however, the apertures in the rear face of the body may be offset from the pins projecting from the front face of the body.

Each connector device in the body may be adapted to receive within it one of the pins of another electrical plug. The pins from the other electrical plug will usually be the pins from another electrical plug in accordance with the invention. It will however be appreciated that the last plug in a row of stacked plugs could be a known conventional plug.

Each connector device is advantageously a U-shaped connector device. Other types of connector device such for example as cylinders may be employed.

The U-shaped connector device may be formed from a bent strip of metal which is secured at its base to one end of its associated pin. The U-shaped connector device may be welded, soldered or brazed to its associated pin. The U-shaped ccnnector device may be connected to its associated pin by other means such for example as screws, or it may be integrally formed with its pin.

Usually, the body of the plug will be in two portions, in order to enable access to be gained to the interior of the body of the plug.

The two portions of the body of the plug will usually be screwed together as in known conventional plugs.

The terminal devices will usually be screw and cylinder arrangements. The screw and cylinder arrangements may be attached to or formed as part of the connector devices or the actual pins, as may be desired.

The terminal devices may also be screwless connections, for example friction connections as are currently available on the market.

The electrical plug will usually include clamp means for clamping the electrical lead to the plug.

The clamp means may comprise a bridge member and a pair of screws.

Alternatively, the clamp means may comprise one or more flexible gripper members which are such that they flex and grip the electrical lead.

The electrical plug may include a shutter device for blanking off some or all of the apertures in the rear face of the body. Usually, the apertures for the live and the neutral pins will be blanked off. If desired, the aperture for the earth pin may also be blanked off. The shutter device may operate in the manner of any one of the known shutter devices.

The electrical plug may include an ON/OFF switch.

The ON/OFF switch may be a rocker switch. other types of switch may be employed and the various switches may be of generally known construction.

The electrical plug may include visual indicator means for indicating when the switch is in an ON condition.

The visual indicator means is preferably a neon light.

The electrical plug may include one or tWo fuse receiving means each for receiving a fuse. The or each fuse receiving means may be a pair of U-shaped metal cups, each Ushaped metal cup being for receiving one metal end of a fuse. Various types of construction for the fuse receiving means are known and are usually connected to the positive pin.

Where the electrical plug includes the fuse receiving means, the electrical plug may be sold with or without a fuse.

Embodiments of the invention will now be described solely by way of example and with reference to the accompanying drawings in which: Figure 1 shows a first electrical plug; Figure 2 shows a second electrical plug; Figures 3 and 4 are respectively front and side views of a pin and its associated connector device; and Figure 5 shows four of the plugs shown in Figure 1 stacked together and connected to a trailing socket.

Referring to Figure 1, there is shown an electrical plug 2 comprising a body 4. The body 4 is in two portions 6,8 as shown and these two portions 6,8 can be secured together by one or more screws in the manner of a known conventional plug. The body 4 has a front face 10 and a rear face 12. The screw or screws connecting the body portions 6,8 together will usually pass from the front face 10 towards the rear face 12.

The plug 2 has three pins 14 (only two pins 14 being shown) projecting from the front face 10 of the body 4. The pins 14 are of a rectangular cross sectional shape. The rear face 12 of the body 4 is provided with three rectangular apertures 16. The apertures 16 are in line with the pins 14, there being one aperture 16 for each pin 14.

The plug 2 shown in Figure 1 also comprises an electrical lead 18 which enters the body 4 through an electrical lead inlet aperture (not shown) located in the portion 8 of the body 4.

Referring now to Figure 2, there is shown a plug 2 which is similar to the plug 2 shown in Figure 1 and in which similar parts have been given the same reference numerals. The plug 2 shown in Figure 2 additionally comprises an ON/OFF rocker switch 20 for turning the plug 2 on and off. The switch 20 will usually be associated with the pin 14 that is the live pin.

Visual indicator means in the form of a neon light 22 is also provided for indicating when the plug 2 is on or off, the neon light 22 being illuminated when the plug 2 is on.

Figures 3 and 4 show one of the pins 14 and the illustrated pin 14 can be used in either of the plugs shown in Figures 1 or 2.

The pin 14 is shown in Figures 3 and 4 is connected at its inner end 24 with a connector device 26. As can be seen, the connector device 26 is a U-shaped connector device and it is formed from a bent strip of metal which is secured at its base 28 to the inner end 24 of the pin 14. The connector device 26 can be secured at its base 28 to the inner end 24 of the pin 14 by welding, soldering, brazing or any other desired means.

Attached to the connector device 26 is a terminal device 30. The terminal device 30 comprises a screw 32 which screws into a cylinder 34 to trap the bare end of a wire (not shown) from the lead 18 and to thus electrically connect the wire to the pin 14 and to the connector device 26.

It will be appreciated from Figure 5 that the pins 14 of one plug 2 can be pushed through the apertures 16 of an immediately preceding plug 2 such that the pins 14 will be received in their appropriate connector device 26 in the immediately preceding plug 22. In Figure 5, the pins 14 from the inner most plug 2 are connected into a trailing socket 36 as shown.

The trailing socket 36 has an electrical lead 38.

Although not shown in the drawings, the plugs 2 will usually be provided with clamp means for clamping the lead 18 to the plug 2.

The clamp means may be any desired clamp means such for example as a bridge member and a pair of screws or, alternatively, one or more flexible gripper members which are such that they flex and grip the lead 18.

The plugs 2 will also usually include a shutter device for blanking off some or all of the apertures 16 in the rear face 12 of the body 4 of the plugs 2.

Still further, the plugs will usually preferably include fuse receiving means such for example as a pair of U-shaped metal cups (not shown), each U-shaped metal cup being for receiving one metal end of a cartridge fuse (not shown).

The plugs 2 will usually be 13 amp plugs but they can obviously be lower or higher amperage rated plugs if desired.

It will be immediately seen from Figure 5 that the plugs 2 stack together in a simple, pleasing and space saving manner. There is no need to employ an adaptor with an unsightly and bulky conglomerate of known conventional plugs. Since the plugs 2 are provided with the leads 18, they have all the advantages of conventional known plugs and the additional advantage of dispensing with the need for the known conventional and bulky adaptor which is not provided with a lead 18 and merely serves as a carrier for the known conventional plugs.

It is to be appreciated that the embodiments of the invention described above with reference to the accompanying drawings have been given by way of example only and that modifications may be effected. Thus, for example, although the illustrated plugs 2 are 3-pin plugs, it will be appreciated that the plugs 2 could also be 2-pin plugs. The pins 14 can be of a circular or any other desired cross section. Although Figure 5 illustrates the plug 2 being connected to a trailing socket 36, it will be appreciated that the trailing socket 36 could equally well be a conventional wall socket. Shutters employed for blocking off some or all of the apertures 16 will usually be spring loaded safety shutters but other types of shutter can be employed.

The plugs 2 can be used in this country and abroad so that the plugs will generally be designed to the requirements of the country using the plugs. If desired, the two portions 6,8 can slide together and then be held in position with a locking screw. The connector device 26 and the pin 14 may be made as one unit and may also embody the terminal.

The plugs may also be Din plugs which usually have a plurality of pins, or phono plugs which usually have a single pin with an appropriate number of electrical contact bands.

Advantageously, the electrical plug of the present invention is provided with two fuses, one to protect the lead outlet and the other to protect the socket outlet against overloading by subsequent plugs. In Figures 3 and 4 where two fuses are to be employed, the connector device 26 will be electrically isolated from the pin 14.

The electrical plug of the present invention may be sold under the trade mark STACK PLUG.

Claims

1. An electrical plug comprising a body having front and rear faces, at least two pins projecting from the front face of the body, at least two apertures in the rear face of the body, at least two connector devices in the body for electrically connecting the pins with pins of another electrical plug that are pushed into the apertures, an electrical lead inlet aperture in the body, and terminal devices for electrically connecting wires from the electrical lead to the pins projecting from the front face of the body, the plug being such that there are apertures in the rear face of the body corresponding in number to the pins projecting from the front face of the body whereby two or more of the plugs can be stacked together.

2. An electrical plug according to claim 1 in which the apertures in the rear face of the body are in line with the pins projecting from the front face of the body.

3. An electrical plug according to claim 1 or claim 2 in which each one of the connector devices is a U-shaped connector device.

4. An electrical plug according to claim 3 in which the U-shaped connector device is formed from a bent strip of metal which is secured at its base to one end of its associated pin.

5. An electrical plug according to any one of the preceding claims in which the terminal devices are screw and cylinder arrangements.

6. An electrical plug according to any one of the preceding claims and including clamp means for clamping the electrical lead to the plug.

7. A electrical plug according to any one of the preceding claims and including a shutter device for blanking off some or all of the apertures in the rear face of the body.

8. An electrical plug according to any one of the preceding claims and including an ON/OFF switch.

9. A electrical plug according to any one of the preceding claims and including visual indicator means for indicating when the switch is in an ON condition.

10. A electrical plug according to any one of the preceding claims and including two fuse receiving means each for receiving a fuse.

11. An electrical plug according to claim 10 and including the fuses.

12. A electrical plug substantially as herein described with reference to the accompanying drawings.