GB2344698A - Safety apparatus for electrical sockets - Google Patents

Abstract

A light bulb socket adapter 1 comprising an upper part rotatable relative to a lower part, whereby a light bulb in situ is removable only when the upper and lower parts are in a relative position such that electric power is no longer supplied to the upper part. The adapter can be used with an existing light bulb socket to improve safety when a bulb is removed.

Description

SAFETY APPARATS FOR ELECTRICAL SOCKETS This invention relates to safety apparatus for electrical sockets. In particular, it relates to safety apparatus for electrical sockets of the type which receive a light bulb.

The invention is particularly useful for table lamps, desk lamps and so on.

Lamp sockets generally comprise a pair of terminals which are arrange to connect with co-operating terminals of a light bulb in order to provide electricai power to the light bulb to illuminate it. The light bulb is generally either of the bayonet type in which a pair of pins are placed into a pair of slots on the socket and the bulb is rotated to bring its contacts into alignment with the contacts of the socket. Alternatively, the bulb may be of the screw-in type which is simply screwed into place in order to connect the respective terminals.

When a tight bulb fails or for other reasons, the bulb has to be removed. leaving the bare terminals on the socket expose. Since switches for lamps, such as table lamps or desk lamps. do not generally have a clear indication of ON and OFF positions, it is quite likely that the lamp will still be in an ON state when the bulb is removed, particularly if the bulb has previously failed such that the user does not know whether it was turned ON or OFF at the time he removes the bulb.

The terminals are still connected to a mains voltage and it is oniy required for a user to bridge them, with a finger for example. in order for a current to flow and the user to experience an electric shock, which could be very serious or even fatal.

The present invention arose in an attempt to devise an improved light socket.

According to the present invention there is provided an adapter for a light bulb socket, comprising means for iocating the adapter within the socket in the position normally occupied bv a buib. etectncai terminals at the lower end of the adapter for connecting to the existing terminais on the socket and at the upper end or the adapter for connecting to the terminals on a bulb and isolating means for breaking electrical connection between the socket and the upper terminals of the adapter if the bulb is not present.

Preferably, the adapter comprises a means for locking the adapter within a socket such that a kev or other specific unlocking device is required to remove it.

The device is preferably in two parts which are rotatable relative to one another, wherebv a light buib ls removable onlv when the two parts are in a relative position such that the eiectrical supply to the top part is isolated.

The invention may be applied to domestic side lamps, festoon lighting, and any other location normally occupied by light bulbs.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows an adapter mounted in a light bulb socket ; and Figure 2 shows schematically the operation of the adapter.

Referring to Figure 1, an adapter I locates within a light bulb socket 2. A bayonet type of connection is shown but the invention is also applicable to other tvpes of connection.. As shown in the side view of Figure 1. the existing socket includes a pair of generally L-shaped slots 3 which are normally used to receive a respective pair of outwardly extenaing pins from a light bulb such that when the bulb is rotated to lock the pins in place, the terminals of the bulb are connected with the terminals of the socket.

The adapter I is of plastics material (or other electrically insulating material) with electrically conductive terminals. It comprises an upper part which itself forms a bulb socket having a pair of diametricallv opposed L-shaped slots 4 and also being provided with upper terminals 5 (shown in Figure 2). These terminais are in the form of pins which extend through the upper part A of the adapter.

The upper part A is mounted by means of a central mount such as a pin 6 such that it can rotate relative to a bottom part B. Bottom part B is also provided with two pins 7 shown in dashed lines in Figure 2. An additional locking key 8 is provided which serves to lock the device to the socket such that it can only be removed with a special key or other tool. Many different locking mechanisms may be used to achieve this.

The adapter preferably includes an indicator, such as a visual indicator 9 (e. g. an LED), which is connected to the upper terminals and so indicates when the upper part is'live'This will enable a user to switch the socket off before inserting a new bulb.

In use, the adapter is located in position in an exposed socket 2, and locked in place. A bulb (not shown) may only be located when the two parts A and B of the adapter are relatively rotated to a position such as that of Figure 2 where the two sets of terminals 5 and 7 are not in contact. Thus, since the adapter is of an insulating material, even if the socket were live, terminals 5 would be insulated therefrom, and thereby the top terminals of the adapter would not be dangerous if inadvertently touched.

The bulb is located and rotated to lock it into place within part A. Further rotation of part A causes the respective terminals 5 and 7 to line up. The bulb can then be lit.

Although both parts A and B are shown with bayonet type fittings, one or both of them may be of different types, e. g. screw in, so that the adapter can also act as an adapter from bayonet to screw type devices for example. Hence, if a user has only one type of bulb and a socket requires a different type, he can simp ! v use an adapter according to the invention to both facilitate using the stocked bulb whilst also rendering the socket safe.

It is seen that the adapter need add only a minimum extra height to a socket, so it can be used with lamps with shades, for example, where there is only a restricted area available for a bulb to sit.

Claims (10)

1. CLAIMS 1. A light bulb socket adapter comprising means for locating the adapter within the socket in the position normally occupied by a bulb; electrical terminals at the lower end of the adapter for connecting to the existing terminals on the socket and at the upper end of the adapter for connecting to the terminals on a bulb, and isolating means for breaking electrical connection between the socket and the upper terminals of the adapter if the bulb is not present.
2. 2. A light bulb socket adapter as claimed in Claim 1, wherein the adapter further comprises a means for locking the adapter within a socket such that a key or other specific unlocking device is required to remove it.
3. 3. A light bulb socket adapter as claimed in Claim 1 or 2, wherein the adapter consists of two parts which are rotatable relative to one another, whereby a light bulb is removable only when the two parts are in a relative position such that the electrical supply to the top part is isolated.
4. 4. A light bulb socket adapter as claimed in Claim 1,2 or 3, wherein the adapter further includes a visual indicator device to alert a user when the socket is electrically live.
5. 5. A light bulb socket adapter as claimed in any preceding claim, which is adapted to receive bayonet type light bulbs.
6. 6. A light bulb socket adapter as claimed in Claims 1 to 4, which is adapted to receive screw-in type light bulbs.
7. 7. A light bulb socket adapter as claimed in any preceding claim, wherein the adapter has a body constructed substantially of electrically insulating material.
8. 8. A light bulb socket adapter as claimed in any preceding claim, wherein the said lower end is adapted to connect to a first connection type socket, and the said upper end is adapted to connect to a bulb of a second connection type.
9. 9. A light bulb socket adapter as claimed in Claim 8, wherein one of the first or second types is bayonet, and the other is screw-in.
10. 10. A light bulb socket adapter, substantially as hereinbefore described, with reference to, and as illustrated by, the accompanying drawings.