WO1994023472A1

WO1994023472A1 - Electrical socket connectors

Info

Publication number: WO1994023472A1
Application number: PCT/GB1994/000717
Authority: WO
Inventors: William Thomas Wood; Robert Ian Sloan
Original assignee: Hogg, Michael, Peter
Priority date: 1993-04-06
Filing date: 1994-04-05
Publication date: 1994-10-13
Also published as: AU6383894A

Abstract

An electrical power socket connector (10) has a pair of sliding shutterplates (20, 21), each provided with an aperture (24). Normally, the shutter plates (20, 21) obscure a recess (12) to receive an earth pin of a plug. Upon pressing two oppositely facing actuator buttons (16) simultaneously, the apertures (24) are brought into register with the recess (12), to allow an earth pin of a plug to be inserted into the recess (12). Thus, in order to insert a plug into the socket connector (10), it is necessary to depress the actuator buttons (16) simultaneously and, also at the same time, to insert the plug into the socket. The spacing of the actuator buttons (16) makes it impossible for a small child to operate the socket, and thereby apply power to a possibly dangerous appliance.

Description

ELECTRICAL SOCKET CONNECTORS

This invention relates to electrical socket connectors, and is concerned particularly, although not exclusively, with wall-mounted power outlet sockets.

Electric power can be dangerous in the home, especially to small children. Various means have been proposed for blocking off wall-mounted power sockets, in order to deter young children from inserting metallic objects into the socket, with possibly lethal results. For example, in the UK, plastic plugs have become widely available, which can be inserted into a conventional 13-amp square-pin power socket, in place of a normal electrical plug. US Patent 5 087 796 (Norman) discloses a more elaborate safety cover for an electrical outlet, which can be maintained in place when an appliance is connected to the outlet. US Patent 4 607 136 (Thomas) discloses a cover for an electrical outlet, which is permanently installed, but may be opened to allow access to the socket.

In addition to the dangerous possibility of inserting objects into an electrical socket, however, there is another very real danger, and one which tends to be encountered more frequently. This is the possibility of a young child being able to provide power to a potentially dangerous appliance, simply by inserting the power plug into the power socket in a normal manner. For example, power tools such as saws and drills can be extremely dangerous to a child, if power is applied to them. Many common household appliances, such as heaters, hair dryers, irons, coffee grinders and liquidizers, may be equally dangerous. Preferred embodiments of the present invention aim to provide electrical power sockets which may be improved in this respect.

More generally, according to one aspect of the present invention, there is provided an electrical socket connector comprising

a recess;

a first electrical conductor in said recess for making electrical contact with a second electrical conductor when inserted in said recess;

shutter means for obstructing said recess to prevent the insertion therein of a said second electrical conductor in order to make electrical contact with said first electrical conductor; and

first and second actuators which are arranged to be actuated manually, and require to be actuated simultaneously, thereby to displace said shutter means from said recess to allow the insertion therein of a said second electrical conductor, in order to establish an electrical connection between said first and second electrical conductors.

Preferably, said shutter means is disposed within a body of said electrical socket connector.

Said shutter means may comprise at least one plate which is adapted to slide across said recess. Said shutter means may comprise at least two said plates, each of which is adapted to be moved against a resilient bias by a force applied manually to a respective one of said actuators.

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Preferably, said actuators are so mutually spaced as to be operable simultaneously by respective digits of an adult's hand, but not a child's hand.

Preferably, said socket connector is an electrical power connector.

Said first electrical conductor may be for establishing an earth or ground connection.

Said socket connector is a wall-mounted connector.

Preferably, said actuators comprise buttons mounted on side walls of a housing of the socket connector.

Said shutter means and actuators may be provided on an adaptor which is adapted to be fitted to an outer face of the socket connector.

The invention extends to an adaptor for use in an electrical socket connector according to the preceding aspect of the invention, the adaptor comprising a cover plate for the electrical socket connector, and said shutter means and actuators mounted on said cover plate.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which:

Figure 1 is a front perspective view of a single wall-mounted electrical power socket;

Figure 2 is a view similar to Figure 1 , but showing a double socket;

Figure 3 is a perspective view of a double adaptor plate;

Figure 4 is a view similar to Figure 1 , showing hidden detail of shutter plates;

Figure 5 is a cross-sectional view of the socket of Figure 4, showing shutter plates in a first position;

Figure 6 is a view similar to Figure 5. but showing shutter plates in a second position;

Figures 7 A and 7B show a shutter plate, respectively in top plan view and side elevation:

Figure 8 is a rear view of a front panel of the socket of Figures 1 and 4;

Figure 9 is a view similar to Figure 8, but showing a single adaptor plate; Figure 10 is a cross-sectional view showing the adaptor plate of Figure 9, in use;

Figure 11 is a view similar to Figure 1 , but showing a different style of power socket;

Figures 12A and 12B are diagrammatic views showing shutter plates of the socket of Figure 11. respectively in first and second positions; and

Figures 13 is a view similar to Figure 1 1 , but showing a double socket.

In the figures, like reference numerals denote like or corresponding parts.

The power socket 10 that is shown in Figure 1 is, in many respects, similar to a conventional wall-mounted 13-amp electrical power socket that is widely used in the UK at the present time. The socket 10 comprises a front plate 11 on which the components of the socket connector are mounted. The front plate 11 is formed with a first recess 12 to receive the earth pin of a corresponding plug, and recesses 13 and 14 to receive the live and neutral pins respectively of such a plug. Fixing screws 15 pass through respective apertures in the front plate 11 , and engage within tapped holes provided in a mounting box (not shown) which typically will be mounted in a recess formed in a wall, or surface mounted on the wall.

In a conventional socket connector of this type in the UK, there is already provided a blanking mechanism for preventing access to the live and neutral terminals located within the recesses 13 and 14. Thus, as will be well known to those familiar with UK-style power connectors, the longer earth pin of an electrical plug has to be inserted firstly in the recess 12, in order to move a blanking plate within the socket downwardly, to open the recesses 13 and 14, and thereby allow the respective live and neutral pins of the plug to pass through the recesses 13 and 14 and engage the electrical conductors therein.

In the socket 10, however, an additional shutter means is provided. An actuator button 16 is provided on each side of the front plate 11, and is operatively connected to a respective shutter plate, which is resiliently biased into a first position in which it closes off the recess 12. In order to allow a plug to be inserted into the socket 10. both of the actuator buttons 16 need to be depressed simultaneously, in order to open the recess 12, and allow the respective plug to be inserted into the socket.

In Figure 1 , only one of the actuator buttons 16 is visible. A similar button is provided on the opposite side of the front plate 11. Further details of this, and of the respective shutter plates, will be described below.

Figure 2 shows a socket which is similar to the socket 10 of Figure 1.

However, as will be seen, the socket 50 is a double socket, having two sets of recesses 12. 13, 14 provided in the front plate 11 , and each with a respective ON/OFF switch 18.

In Figure 2, the two shutter plates of each socket are operated by respective actuator buttons 16 and 17. Each of the actuator buttons 16 is similar to the corresponding button in Figure 1. However, each of the actuator buttons 17 is located on a top face of the front plate 11, and arranged to be slid substantially horizontally, as seen in Figure 2.

The sockets 10 and 50 as shown in Figure 2 have the actuator buttons 16, 17 and respective shutter plates built into the front plate 11, in an integral manner. However, in other embodiments of the invention, adaptor plates may be provided, to adapt existing power sockets.

For example, such an adaptor plate 60 is shown in Figure 3. This is generally similar in layout to the socket 50 of Figure 2. However, in this case, the front plate 11 comprises only a thin plate formed with the recesses

12, 13 and 14, apertures for the fixing screws 15 and an aperture 19 to receive switches. The actuator buttons 16 and 17 are mounted on the front plate 11, as are respective shutter plates to close off the apertures 12. In use, the front plate 11 of Figure 3 is simply fitted over an existing wall socket, using the screws 15 which are spaced at the standard distance for UK wall mounting boxes. The front plate 11 is sufficiently thin as not to prevent good electrical contact between a respective plug and the socket behind the adaptor plate 60.

The socket 10 of Figure 1 will now be described in somewhat more detail, with reference to Figures 4 to 8.

A main body 25 of the socket 10 is mounted on the front plate 11 , and carries all of the electrical components and conductors necessary to provide power to the socket, and the necessary electrical connections to a power plug to be received. Thus, for example, the main body 25 is formed with a recess

26 which registers with the recess 12 in the front plate 11 , and contains an electrical conductor 27 for establishing an electrical connection with the earth pin of a plug, when inserted.

As seen in Figures 4 to 7. there is a left shutter plate 20 and a right shutter plate 21, each carrying a respective one of the actuator buttons 16, each carrying a respective abutment 23, and each being provided with a respective aperture 24. A respective compression spring 22 is connected between each abutment 23 and a wall portion of the main body 25, to urge the respective shutter plate 20 or 21 into the position illustrated in Figure 5. In these positions, the apertures 24 in the shutter plates 20 and 21 are out of register with the recess 12 in the front plate 11. Thus, the recess 12 is obstructed by the shutter plates 20 and 21, and a plug cannot be inserted into the socket 10.

Upon depressing the actuator buttons 16 inwardly, as indicated by the arrows A in Figure 4, the shutter plates 20 and 21 are urged into the positions shown in Figure 6, whereby the apertures 24 come into register with the recess 12, and thereby allow the earth pin of a respective plug to be inserted into the socket connector 10, to make contact with the electrical conductor 27 within the recess 26.

Thus, it may be appreciated, a plug can be inserted into the socket 10 only upon actuating the buttons 16 simultaneously, to open the recess 12. The spacing of the buttons 16 is such that, whilst they can quite conveniently be operated simultaneously by the thumb and a finger of an adult's hand, whilst allowing at the same time the insertion of a plug into the socket 10, they cannot be so operated by a smaller, child's hand. Even if a child could just span the width of the socket 10, its hand would then obstruct the recesses 12. 13 and 14, thereby making insertion of a plug impossible.

Preferably, the spacing of the actuator buttons 16 is in the range 20 to 140 mm, more preferably in the range 40 to 120 mm and, particularly conveniently, in the range 60 to 100 mm.

It will be appreciated that various modifications can be made to the components as illustrated diagrammatically in Figures 4 to 7. For example. actuators other than buttons 16 may be provided. Resilient means other than springs 22 may be used. The abutments 23 may be designed to abut against a portion of the main body 25, when in the positions illustrated in Figure 6, in order to define positive end positions of the shutter plates 20 and 21. A tension spring may be used, between the abutments 23 and an outer part of the main body 25, rather than the illustrated compression spring. Other resilient bias means (e.g. elastomeric members) may be used.

Figure 8 shows a possible internal configuration of the front plate 11 of the socket 10.

In Figure 8, the recesses 13, 14 for the live and neutral connections are covered by an internal blanking plate 35, which is arranged to be moved downwardly (as seen) against a resilient bias, by the action of the earth pin of a plug being inserted into the recess 12. and as the blanking plate 35 is thereby pushed downwardly, the live and neutral recesses 13, 14 are opened. This blanking plate mechanism is typical in a UK-style 13-amp power socket. An earthing plate 30 is mounted on the back of the front plate 11 , and carries two screw holes 31 for engagement by the fixing screws 15, an earth terminal 32 for connection to an earthing conductor, and a conductor portion 27 for resilient engagement with the earth pin of an inserted plug. The earthing plate 30 also carries the shutter plates 20 and 21 and, if those plates are of metal, establishes a safe electrical connection therewith. The shutter plates 20, 21 may be of a material other than metal, however - such as a non- conductive material (e.g. of plastics).

The adaptor plate 80 shown in Figure 9 is generally similar to the socket 10 of Figure 8, in that it is provided with the recesses 12, 13 and 14, the shutter plates 20 and 21 , and the earthing plate 30. However since the adaptor plate 80 of Figure 9 is arranged to fit over an existing wall socket, it does not need to be provided with the blanking plate 35 mechanism - this will already exist in the wall socket which the plate 80 covers.

Figure 10 shows the adaptor plate 80 adjacent an existing electrical socket 70, which it is designed to adapt. The existing socket 70 has a surface mounted wall box 71 , to which a front plate 72 is secured in a conventional manner. The fixing screws 15 are removed (and substituted by slightly longer screws if necessary), then replaced through the adaptor plate 80, to pass through the front plate 72 and be secured in the wall box 70. The adaptor plate 80 thus provides the safety feature of requiring the two buttons 16 to be depressed simultaneously to allow the plug to be inserted into the socket, whilst the existing socket 70 provides all of the other standard features of the wall outlet. As mentioned above, the adaptor plate 80 preferably is as thin as possible, so as not to interfere with the normal working of the plug that is inserted into the socket 70. Although wall mounted power sockets have been described above, of typical UK-style, other embodiments of the invention may be applied equally to electrical connectors of different styles and configuration. For example, the electrical wall socket 90 as shown in Figures 11 and 12 is of a typical continental European style, having a protruding earth pin 92 and live and neutral contacts (not shown) behind respective recesses 13, 14, which are located with the pin 92 within a shallow recess 91.

The socket 90 is provided with a shutter means which is similar to that described above. However, in this case, the shutter plates 20 and 21 cover the recesses 13 and 14 respectively. Thus, in use, the live and neutral pins of an electrical plug cannot be introduced into the recesses 13 and 14, to establish electrical connection with the conductors within the socket 90, until the actuator buttons 16 have been depressed simultaneously, to bring the respective apertures 24 into register with the recesses 13 and 14. This action is illustrated in Figures 12A and 12B. In this example, each of the shutter plates 20 and 21 is formed with two apertures 24 spaced at the spacing of the recesses 13 and 14, so that each shutter plate closes off and opens both of the recesses 13 and 14.

The electrical socket 100 shown in Figure 13 is a double version of the socket 90 of Figures 1 1 and 12. In Figure 13, however, each of the two sockets has been rotated through 90 degrees, so that the actuator buttons 16 are now situated respectively at the top and bottom edges of the socket 100 (as seen in Figure 13). It is not necessary for both of the sockets in Figure 13 to be orientated in exactly the same way. For example, each socket may have its respective earth pin 92 at the centre part of the connector 100, so that each individual socket effectively faces in an opposite direction. It is possible to modify the double 13-amp socket shown in Figures 1 and 2 in a way similar to that shown in Figure 13. such that each socket is likewise rotated through 90 degrees - and. optionally, the earth recesses 12 may each be towards the centre of the connector.

It will be appreciated that embodiments of the invention may be applied to electrical socket connectors other than those illustrated. For example, embodiments of the invention may be applied to electrical outlet sockets of the type commonly used in the USA. In such embodiments, as well as those shown in Figures 1 1 to 13. an extra advantage is obtained in embodiments of the invention, by providing positive shuttering of the recesses 13, 14 for the live and neutral connectors. Typically, such shuttering is not provided in continental European and US-style socket connectors.

Embodiments of the invention can be applied to sockets other than wall-mounted sockets - for example, trailing sockets. Although embodiments of the invention may provided particular advantage when applied to electrical power socket connectors, other embodiments of the invention may be applied to other electrical socket connectors - for example, connectors used in telecommunications.

Means other than the sliding shutter plates 20, 21 may be employed, to close off the recesses 12. 13 and 14. For example, alternative plates that are arranged to rotate about a pivot may be employed. Other obstructing means may be used to block the passage of an electrical conductor into a recess such as 12. 13 and 14. Thus, in the context of this specification, the term "shutter means" is to be construed broadly, to cover all such suitable alternative arrangements. Where the shutter plates 20, 21 are made of a conductive material such as metal, the actuator buttons 16 are preferably made of a suitable, durable, non-conductive material.

Although embodiments of the invention have been shown as having shutter means that obstruct one or two recesses in a socket connector, upon actuating two actuators, other embodiments of the invention may have shutter means that obstruct more than two recesses in a socket connector, and/or may have more than two actuators.

In this specification, terms of absolute orientation are used conveniently to denote the usual orientation of items in normal use and/or as shown in the accompanying drawings. However, such items could be disposed in other orientations, and in the context of this specification, terms of absolute orientation, such as "top" , "bottom " , "left" , "right" , "vertical" or "horizontal" , etc. are to be construed accordingly, to include such alternative orientations.

The reader^'s attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one. or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS:

1. An electrical socket connector comprising

a recess:

2. An electrical socket connector according to claim 1 , wherein said shutter means is disposed within a body of said electrical socket connector.

3. An electrical socket connector according to claim 1 or 2, wherein said shutter means comprises at least one plate which is adapted to slide across said recess.

4. An electrical socket connector according to claim 3, wherein said shutter means comprises at least two said plates, each of which is adapted to be moved against a resilient bias by a force applied manually to a respective one of said actuators.

5. An electrical socket connector according to any of the preceding claims, wherein said actuators are so mutually spaced as to be operable simultaneously by respective digits of an adult's hand, but not a child's hand.

6. An electrical socket connector according to any of the preceding claims, wherein said socket connector is an electrical power connector.

7. An electrical socket connector according to any of the preceding claims, wherein said first electrical conductor is for establishing an earth or ground connection.

8. An electrical socket connector according to any of the preceding claims, wherein said socket connector is a wall-mounted connector.

9. An electrical socket connector according to any of the preceding claims, wherein said actuators comprise buttons mounted on side walls of a housing of the socket connector.

10. An electrical socket connector according to any of the preceding claims, wherein said shutter means and actuators are provided on an adaptor which is adapted to be fitted to an outer face of the socket connector.

11. An adaptor for use in an electrical socket connector according to claim 10, the adaptor comprising a cover plate for the electrical socket connector, and said shutter means and actuators mounted on said cover plate.