GB2546108A

GB2546108A - Electrical wiring accessory socket outlet with shutter

Info

Publication number: GB2546108A
Application number: GB1600440.0A
Authority: GB
Inventors: Bickerdike Anthony; Murray Lonergan Lawrence
Original assignee: Electrium Sales Ltd
Current assignee: Electrium Sales Ltd
Priority date: 2016-01-11
Filing date: 2016-01-11
Publication date: 2017-07-12
Anticipated expiration: 2036-01-11
Also published as: GB201600440D0; GB2546108B

Abstract

An electrical outlet socket comprises a face plate 1 provided with a plurality of holes 10, 12, 14 for reception of corresponding pins of a compatible plug, and a shutter 16. The shutter is resiliently biased towards a first position and operable by insertion of a pin into a first one 10 of the holes to expose contacts corresponding to further holes 12, 14. In the first position, the further holes are completely obscured and the first hole is at least partially obscured. The shutter is constrained to move in a plane parallel to the face plate, but is free to rotate a certain amount. Thus if only a single second pin is applied, the shutter will rotate and block against obstacles 30, preventing access to the further holes.

Description

Electrical Wiring Accessory Socket Outlet with Shutter

Mains electrical outlet sockets for the United Kingdom and some other territories have three holes, to mate with a corresponding three-pin plug. They are known as IEC Type G plugs and sockets. In the context of the United Kingdom, they are referred to as BS1363 plugs and outlet sockets. A safety shutter is provided, and is actuated by insertion of the Earth pin of the plug, which is longer than the remaining Live and Neutral pins. As the Earth pin is inserted, the shutter opens to expose Live and Neutral contacts. The Live and Neutral pins of the plug may then be inserted into the socket.

Although the safety provided by such shutters exceeds the safety provided by the mains electrical outlet sockets used in most other territories, the present invention seeks to im-provide yet further safety features for the shutter arrangement .

Although the conventional shutter arrangement is designed to prevent access to Line and Neutral contacts unless the Earth pin is inserted into the correct hole, it is possible to tamper with the socket, opening the shutter by inserting some inappropriate instrument into the hole intended for the Earth pin, and gaining access to the Live and Neutral connections within the socket.

The present invention provides and improved shutter arrangement for IEC type G (BS1363) sockets.

The above, and further, objects, characteristics and advantages of the present invention will become more apparent from the following description of certain embodiments thereof, in conjunction with the accompanying drawings, wherein:

Fig. 1 schematically illustrates a socket according to an embodiment of the present invention in a CLOSED position in a normal operation of insertion of a compatible plug;

Fig. 2 schematically illustrates a part cross-section through the shutter of Fig. 1, along the line II-II;

Fig. 3 schematically illustrates a part cross-section through the shutter of Fig. 1, along the line III-III; and

Fig. 4 schematically illustrates the socket of Fig. 1 in a state corresponding to tampering by insertion of an implement into the Earth hole and attempted insertion of an implement into the Live hole but not the Neutral hole.

The present invention provides a shutter arrangement in which the shutter will not open to expose the Live and Neutral contacts even if an instrument is inserted into the Earth hole. Furthermore, the shutter will not open to expose Live and Ne-tural contacts unless pins of a compatible plug, or at least an object with very similar shape and dimensions, is inserted into both the Live and Neutral holes silultaneously.

Fig. 1 illustrates a view of an arrangement of the present invention. A front plate 1 with Earth 10, Neutral 12 and Live 14 holes according to IEC Type G standard is shown, with the holes represented in phantom. A shutter 16 according to a feature of the present invention is shown. Partial cross-sections through the shutter 16 are shown in Figs. 2 and 3, and correspond to partial cross-sections along lines II-II and III-III respectively.

Fig. 1 shows the shutter in a first position, corresponding to a CLOSED position. The Live 14 and Neutral 12 holes are shown closed by the shutter 16.

The part of the shutter exposed by the Earth hole has a ramped edge 20, visible in Fig. 3. On insertion of an Earth pin of an IEC Type G (BS1363) plug or similar into the Earth hole 10, pressure of the pin on the ramped edge 20 will drive the shutter in the direction of the bottom of Fig. 1 against the bias of spring 22, into a second position. However, the length of the ramped edge 20 is not sufficient that the shutters will expose the Live and Neutral contacts in this second position, even with the Earth pin fully inserted.

Insertion of the Earth pin into the Earth hole 10 will only open the shutter a certain amount, into its second position, enough to expose ramped parts 26 of the shutter 16 through the Live 14 and Neutral 12 holes. The Live and Neutral pins going in to the Live 14 and Neutral 12 holes will engage with the respective ramped parts 26 to drive the shutter fully open, into its third position. Unlike conventional IEC type G sockets, the shutter is not driven fully open by insertion of the Earth pin. The shutter of the present invention takes up one of three distinct positions: a first position in which no pins are inserted, and the shutter is driven by resilient bias such as a spring 22 to close the Live 14 and Neutral 12 holes, and to at least partially close the Earth hole 10; a second position where the insertion of an Earth pin into the Earth hole 10 drives the shutter clear of the Earth hole, but still obscures the Live and Neutral holes; and a third position where insertion of Live and Neutral pins into the Live and Neutral holes drives the shutter clear of the Live and Neutral holes.

Fig. 2 shows a partial cross-section of shutter 16 along line II-II of Fig. 1. This part of the shutter is the part which closes the Live 14 and Neutral 12 holes when no plug is engaged. A planar part 24 is exposed through the Live and Neutral holes when no plug is engaged. Once the Earth pin is engaged, the shutter 16 is driven against the bias of spring 22, and a ramped part 26 is then exposed through the Live and Neutral holes. On insertion of an IEC type G plug, the Live and Neutral pins will bear against the ramped parts 26, and drive the shutter further against the bias of spring 22, to open the Live and Neutral holes and allow entry of the corresponding Live and Neutral pins of the plug.

According to a feature of the present invention, a number of obstacles 30 are provided, as illustrated in Fig. 1. In the illustrated embodiment, they are moulded into the material of the face plate 1, but they could be provided as separate components or indeed by any appropriate assembly.

When an IEC Type G plug in inserted into the socket, shutter 16 is driven against the bias of the spring and this motion is not impeded by any of the obstacles 30.

On the other hand, Fig. 4 illustrates an embodiment of the present invention in its operation where an attempt is made to access the Live contact with an implement other than an IEC Type G (BS1363) plug. An implement of some sort has been inserted into the Earth hole, and has driven the shutter 16 against the bias of spring 22 into its second position. Next, an implement has been pressed into Live hole 14 in an attempt to gain access to the Live contact. The implement has pressed against ramped part 26. It has driven the part of shutter 16 exposed by Live hole 14 against the bias of spring 22. However, no corresponding drive has been applied to the ramped part 2 6 of the part of shutter 16 exposed by Neutral hole 12. Shutter 16 is restrained in a plane parallel to the plane of the drawing, but is not restrained against rotation other than by the spring 22 and obstructions 30. As drive is applied to the Live side of the shutter but not the Neutral side, the shutter 16 rotates to the position illustrated.

Various obstructions 30, which may be moulded into the material of the face plate 1, are provided and prevent the shutter 16 from opening further from this rotated position. The precise location and form of the obstructions will vary with the precise form of the shutter. However, as in the illustrated embodiment, the position and form of the obstructions 30 is such that they do not impede normal operation of the shutter: as shown in Fig. 1, but they do prevent the opening of the shutter to an extent sufficient to expose either Live or Neutral contacts when an implement is inserted into either one of the Live and Neutral holes to apply drive to only one or other of the Live and Neutral sides.

While the present invention has been described with reference to a limited number of particular embodiments, numerous modifications and variations will be apparent to those skilled in the art. The precise form and shape of the shutter 16 and obstructions 30 may vary, provided that they work together as described and meet the standards required for the type of socket involved.

The present invention has been described with reference to an IEC type G (BS1363) mains outlet socket, it may be applied to other sockets, with suitable adaptation to the form of the shutter 16 and obstructions 30. The shutter has been shown and described as being biased towards its closed position by a single spring, but it may in fact be held and biased by any suitable resilient bias means which allows the required degree of rotation into engagement with the associated obstructions 30 when an attempt is made to open the shutter with an unsuitable instrument.

Claims

1. An electrical outlet socket comprising a face plate (1) provided with a plurality of holes (10, 12, 14) for reception of corresponding pins of a compatible plug, and further provided with a shutter (16) resiliently biased towards a first position and operable by insertion of a pin into a first one (10) of the holes to expose contacts corresponding to further holes (12, 14), wherein, in the first position, the further holes are completely obscured and the first hole is at least partially obscured, characterised in that: the shutter is constrained to move in a plane parallel to the face plate (1), but is free to rotate a certain amount, wherein insertion of the pin into the first one (10) of the holes causes the shutter to be driven away from the first position into a second position such that the first one of the holes (10) is not obscured by the shutter and wherein parts of the shutter exposed through the further holes (12, 14) when the shutter is in the second position carry ramped portions (26) whereby the shutter (16) is further operable by insertion of corresponding pins of a compatible plug into the further holes, to drive the shutter into a third position such that the further holes are not obscured by the shutter (16) and electrical contacts are accessible through the further holes.

2. An electrical outlet socket according to claim 1 wherein, in response to insertion of an implement into only one of the further holes (12; 14) when the shutter is in the second position, the shutter rotates into engagement with an obstruction (30), which impedes further opening of the shutter, such that electrical contacts are not exposed through the further holes.

3. An electrical outlet socket according to claim 1 or claim 2 wherein the electrical outlet socket is an IEC type G mains outlet socket.