GB2237455A

GB2237455A - Branching electric connector

Info

Publication number: GB2237455A
Application number: GB8921743A
Authority: GB
Inventors: Brian Rose
Original assignee: Electricity Council
Current assignee: Electricity Council
Priority date: 1989-09-27
Filing date: 1989-09-27
Publication date: 1991-05-01
Also published as: GB8921743D0

Abstract

A branching connector comprises a plug having pins 6a, 6b connected electrically to a cable 2 and to a socket outlet. The cable is preferably prewired to the connector. Interconnection of branching connectors is prevented by interference means 13 and 14. This prevents cascading of the electric connectors which is undesirable on safety grounds. The connector may be used with a standard British 13A outlet. <IMAGE>

Description

ELECTRIC CONNECTOR The present invention relates to an electric connector for connecting an appliance to an electric power outlet.

A common problem with domestic electricity supply outlets is the insufficient number of outlets at required locations and the cost and disruption of providing more. There is also a growing tendency for people to expect to leave domestic appliances in one place for long periods, plugged in and with the lead tidied neatly, especially in kitchens.

The conventional plug-in fused adaptors address the problem of a limited number of outlets, but do not provide a tidy cable route. The unfused adaptor is additionally unsatisfactory on grounds of safety and reliability.

Accordingly the present invention provides an electric connector for connecting an appliance to an electric power outlet comprising a housing containing cable termination means for connection with an appliance power cable, inlet power connection means adapted to provide a power interconnection with said electric power outlet and secondary power outlet means adapted to provide a secondary power outlet for interconnection with a further electric connector when said electric connector is connected to said electric power outlet.

In a preferred embodiment, the electric connector is adapted to be received in a 13 amp British Standard domestic electricity outlet, wherein said inlet power connection means comprises three electrically conductive pins projecting perpendicularly from a back face of said housing at positions arranged to correspond to receiving sockets in said electricity outlet, said cable termination means provides electrical connection between the wires of said appliance cable and said electrically conductive pins and said secondary power outlet comprises channels from a front face of said housing to positions adjacent to and electrically connected to a top portion of said conductive pins, said channels arranged to receive electrically conductive pins of said further electric connector.

Preferably, the present invention includes an interference means arranged to prevent a further said electric connector from being received in the secondary power outlet of said electric connector.

In the embodiment in which the electric connector is adapted to be received in a 13 amp British Standard domestic electricity outlet, said interference means comprises an extension of the top of the back face of said housing forming a tab and an anti-cascade protrusion on the top of the front face of said housing, both arranged at positions such that said tab of a further said electric connector co-operates with said anti-cascasde protrusion of said electric connector to prevent a further said electric connector from being received in the secondary power outlet of said electric connector.

Preferably, the present invention also includes an opening in said housing in the bottom face thereof, providing access to said cable termination means for said appliance power cable. This embodiment enables tidier cable routing, since the appliance power cable of the electric connector is in a corresponding position to the appliance power cable position of a standard plug.

In a preferred embodiment of the present invention, said cable termination means comprises recesses in said electrically conductive pins and screws clamping said wires of said appliance power cable in said recesses.

In an alternative embodiment, said wires of said appliance power cable are permanently affixed to said electrically conductive pins to form said cable termination means.

An example of the present invention will now be described with reference to and illustrated by the accompanying drawings, in which: Figure 1 is a part sectional side elevation of a three pin electric connector according to one embodiment of the present invention; Figure 2 is the embodiment illustrated in Figure 1 with a standard plug fitted in tandem; Figure 3 is a plan view of the pin layout and socket connector layout according to the embodiment illustrated in Figure 1.

Referring now to the drawings. The example of the present invention illustrated is one in which the electric connector is designed for use with British Standard 13 amp three pin domestic electricity outlets. Therefore, many of the features of this connector are features commonly used in plugs of the prior art.

The housing 1 is of similar shape to a British Standard appliance plug, except that it has additional features which comprise the interference means. The housing 1 is also of slightly larger dimensions than a standard appliance plug, since it has to accommodate both cable termination means and secondary outlet means, whereas a standard plug will only contain cable termination means.

The cable termination means in this example of the electric connector, comprises screws 3 clamping two of the wires 4 of an appliance power cable 2 in recesses 5 in the top portion of two of the pins 6a and 6b (the earth and neutral pins) and one live wire of the wires 4 in a recess at one end of the fuse holder 11. The other end of the fuse holder 11 is formed on the top portion of the live pin 6c. The two ends of the fuse holder 11 are formed from spring type material such as brass, that will grip fuse 12 when inserted, and provide a good electrical connection.

Thus the wires 4 of an appliance power cable 2 are electrically connected by the cable termination means such that the neutral wire is connected to pin 6b, the earth wire is connected to pin 6a and the live wire is connected via the fuse to pin 6c, thus conforming to the British Standard pin layout.

Pins 6a, 6b and 6c protrude from the back face of the housing 1 in the configuration of a British Standard plug, to be received in a British Standard 13 amp domestic electricity outlet.

The secondary outlet means within the housing 1, comprises sockets 7 and channels 9. The sockets 7 are positioned adjacent the top portion of the pins 6a, 6b and 6c and are integrally connected. The sockets 7 are formed from a spring type material such as brass, to receive and grip the pins of a standard plug 8 when fitted in tandem, as shown in Figure 2.

When a standard plug is thus received, electrical connection is provided between the pins 6a, 6b and 6c and their associated pins of the standard plug 8. To guide the pins of the standard plug 8 to the sockets 7, there are provided channels 9 of the same configuration as the pins of the standard plug 8.

These channels 9 run from the front face of the housing 1 to the sockets 7, enabling a standard plug 8 to be fitted to the front face of the housing 1. The standard plug 8 is thus retained in position by the gripping action of the sockets 7.

Within the housing 1, inside the front face, covering the open ends of the channels 9, there are provided electrically isolating shutters 10. These shutters are provided for safety, to prevent access to the live components of the electric connector when no standard plug is fitted. The three shutters 10 are interconnected and the shutter covering the channel for the earth pin has an external cam face that is at a substantial angle to the front face of the housing 1. The shutters 10 are urged to the closed position by a spring or the like and can slide parallel to the front face of the housing 1 upon the insertion of the earth pin of a standard plug. When a standard plug is removed, the shutters 10 will be urged to the closed position by the spring or the like.The shutters 10 hereinabove described are commonly used in domestic electricity outlets of the prior art and are an important safety feature, preventing access to the live components of the socket.

The bottom face of the housing 1 has an opening, through which the appliance power cable 2 enters. The cable may be gripped for safety, as it enters the housing, to prevent the wires 4 from being disconnected from the cable termination means by force. Any method disclosed in prior art may be used for this purpose, such as clamping with a strap and screws or gripping with flexible jaws.

The housing 1 is different in shape to standard plugs as hereinbefore mentioned, since the housing also forms the interference means. The upper part of the back face of the housing 1 is extended to form a tab 13 which makes the upper part of the electrical connector bigger than that of a standard plug. The housing 1 further has an anti-cascade protrusion 14 situated on the upper part of the front face of the housing 1. This is at a position that will not prevent a standard plug from being received in the channels 9 and sockets 7 of the secondary outlet means. However, it is in a position such that when attempting to plug a second electric connector of the kind described herein into the secondary output means of the first electric connector, the tab 13 of the second electric connector clashes with the anti-cascade protrusion 14 of the first electric connector.The anti-cascade protrusion 14 protrudes from the front face of the housing 1 to a distance such that the pins of a second electric connector are prevented from reaching the sockets 7 at the end of the channels 9. Hence, electrical connection between two like electric connectors is prevented. The electric connectors cannot therefore be cascaded and only two appliances can be connected to an electric power outlet, the first appliance being connected to the electric connector herein before described, and the second appliance being connected to a standard plug fitted in tandem to the electric connector. This is an important safety feature, since cascading of these plugs could lead to the overloading of the electric power outlet.

Another example of the present invention is one in which the electric connector comprises a plug moulded permanently to the appliance power cable.

This example differs from the one herein before described in that the bottom face of the housing does not have an opening but is formed to be integrally connected to the appliance power cable insulation sleeving. Further, the cable termination means comprises a permanent attachment between the wires of the appliance power cable and the pins. Such attachment being for example by soldering.

Claims

1. An electric connector for connecting an appliance to an electric power outlet comprising a housing containing cable termination means for connection with an appliance power cable, inlet power connection means adapted to provide a power interconnection with said electric power outlet and secondary power outlet means adapted to provide a secondary power outlet for interconnection with a further electric connector when said electric connector is connected to said electric power outlet.

2. An electric connector as claimed in claim 1 adapted to be received in a 13 amp British Standard domestic electricity outlet, wherein said inlet power connection means comprises three electrically conductive pins projecting perpendicularly from a back face of said housing at positions arranged to correspond to receiving sockets in said electricity outlet, said cable termination means providing electrical connection between the wires of said appliance cable and said electrically conductive pins and said secondary power outlet comprises channels from a front face of said housing to positions adjacent to and electrically connected to a top portion of said conductive pins, said channels arranged to receive electrically conductive pins of said further electric connector.

3. An electric connector as claimed in claim 2 wherein said cable termination means comprises recesses in said electrically conductive pins and screws clamping said wires of said appliance power cable in said recesses.

4. An electric connector as claimed in claim 2 wherein said wires of said appliance power cable are permanently affixed to said electrically conductive pins to form said cable termination means.

5. An electric connector as claimed in any preceding claim further including an interference means arranged to prevent a further said electric connector from being received in the secondary power outlet of said electric connector.

6. An electric connector as claimed in claim 5 wherein said interference means comprises an extension of the top of the back face of said housing forming a tab and an anti-cascade protrusion on the top of the front face of said housing, both arranged at positions such that said tab of a further said electric connector co-operates with said anti-cascade protrusion of said electric connector to prevent a further said electric connector from being received in the secondary power outlet of said electric connector.

7. An electric connector as claimed in any preceding claim which further includes an opening in said housing at the bottom face thereof, providing access to said cable termination means for said appliance power cable.

8. An electric connector substantially as hereinbefore described with reference to and illustrated by the accompanying drawings.