GB2165710A

GB2165710A - Improvements in or relating to electrical plugs

Info

Publication number: GB2165710A
Application number: GB08425890A
Authority: GB
Inventors: David Cammiss
Original assignee: Individual
Current assignee: Individual
Priority date: 1984-10-12
Filing date: 1984-10-12
Publication date: 1986-04-16
Also published as: GB8425890D0

Abstract

An electrical plug and socket arrangement comprises a plug (10) with two or more pins (18, 20) and a cooperating sockets (12), with apertures (26) for receiving the pins, wherein at least one of the pins (18) of the plug includes a recessed region (22) for receiving a cooperating member (36) associated with the power supply switching mechanism of the socket, the arrangement being such that power can only be supplied to the plug when the plug is fully engaged in the socket and the member is engaged in the recess. Because power can only be supplied to the plug when the plug is fully engaged in the socket and when the member is engaged in the recess, the switching arrangement effectively acts to lock and retain the plug in the socket while the power is on. This means that a live plug cannot be removed from the socket, eliminating the risk of electrocution by touching exposed live pins. <IMAGE>

Description

SPECIFICATION Improvements in or relating to electrical plugs Field of invention This invention relates to electrical plugs and is considered particularly with an electrical plug and socket arrangement, comprising a plug with two or more pins and a cooperating socket with apertures for receiving the pins, such as are widely used for domestic electric power supply purposes.

Background to the invention.

With conventional domestic plug and socket arrangements, a plug can become partly removed from the socket while power is still being supplied to the plug, exposing live pins of the plug. In this condition there is a risk of electrocution occurring, particularly to children who may inadvertantly touch exposed live pins, and it is accordingly an object of the invention to provide an improved plug and socket arrangement.

The invention.

According to the present invention there is provided an electrical plug and socket arrangement comprising a plug with two or more pins and a cooperating socket with apertures for receiving the pins, wherein at least one of the pins of the plug includes a recessed region for receiving a cooperating member associated with the power supply switching mechanism of the socket, the arrangement being such that power can only be supplied to the plug when the plug is fully engaged in the socket and the member is engaged in the recess.

With an arrangement in accordance with the present invention, because power can only be supplied to the plug when the plug is fully engaged in the socket and when the member is engaged in the recess, the switching arrangement effectively acts to lock and retain the plug in the socket while the power is on.

This means that a live plug cannot be removed from the socket, eliminating the risk of electrocution by touching exposed live pins.

While the invention is applicable generally to plug and socket arrangement it finds particular application in domestic arrangements, e.g.

comprising conventional round or square pin plugs with corresponding sockets.

The recess is preferably provided in the earth pin, if present. This is generally the largest plug pin and so is physically easiest to work with. Also, this is preferred for safety reasons.

A conventional plug can easily be converted by removing one of the pins, e.g. the earth pin, and substituting a notched pin which may otherwise be identical to the original. Removed pins can be notched and reused.

The switching mechanism conveniently comprises a slider switch in place of a conventional rocker switch of a domestic socket, linked rigidly to the member, e.g. in the form of a peg, aligned with the position of the pin recess for movement towards and away therefrom. For example, the recess may be located in the upper surface of the top, earth, pin of a plug, with a peg located for vertical sliding movement.

The invention will be further described, by way of example, with reference to the accompanying drawings.

In the drawings.

Figure 1 is a perspective view of a plug forming part of an arrangement in accordance with the present invention; Figure 2 is a schematic side view of a socket forming part of an arrangement in accordance with the present invention; Figure 3 is a front view of the socket of Fig. 2; Figure 4 shows the plug of Fig. 1 located in the socket of Figs. 2 and 3, with the switching arrangement in the 'OFF' position; and Figure 5 is a view similar to Fig. 4 showing the switching arrangement in the 'ON' position.

Detailed description of the drawings.

The illustrated arrangement comprises an electrical plug 10 with cooperating socket 12.

The plug 10 is of generally conventional construction, comprising a housing 14 of insulating material, e.g. rigid plastics material, located at one end of an electrical flex 16. The plug includes an earth pin 18 and also live and neutral pins 20, and is internally wired in conventional manner.

Earth pin 18 includes a trapezoidal section cut out region 22 in its upper face. The plug may be produced simply by modifying a conventional plug by removing the standard earth pin and substituting pin 18 with the cut out region. The conventional earth pin may be then provided with a cut out and recycled for use in further plugs.

Socket 12 is also generally of conventional construction and comprises a front plate 24, e.g. of rigid plastics material, with three rectangular apertures 26 for receiving the plug pins. The apertures lead to associated pin receiving sleeves 28 within the socket, with appropriate mains wiring 30.

In place of a conventional rocker switch, the socket includes a slider switch comprising a slider switch member 32 arranged for sliding movement in slot 34 in the socket front plate 24. As shown in Figs. 4 and 5, the switch member 32 is rigidly linked to peg 36 located behind the front plate 24 by a suitable linkage e.g. of rigid plastics material. Peg 36 is arranged for sliding movement in response to sliding movement of switch member 32. The switch member and peg may be moved be tween upper, 'OFF', positions, as shown in Fig. 4 and lower, 'ON', positions as shown in Fig. 5. In the 'OFF' position peg 36 is completely disengaged from cut out 22, and the plug 10 can be freely removed from and inserted into the socket. In contrast, in the 'ON' position peg 36 is located in and engages with the cut out 22, preventing movement of the plug relative to the socket.

The switching arrangement is linked to the mains supply so that power is supplied to the plug 10 only when the switch 32 and peg 36 are located in their lower, 'ON', positions, as shown in Fig. 5. It will thus be clear that power can only be supplied to a plug when the plug is fully inserted in the socket and the peg 36 is located in the cut out 22. In this condition, the switching arrangement acts to lock the plug in the socket, making it impossible for the plug to be partially removed from the socket exposing live pins. The risk of electrocution from such an arrangement is thus significantly reduced.

It will be apparent that the above described arrangement can be modified in various ways.

For example, the construction and arrangement of the switching mechanism may be varied without affecting the functioning of the arrangement.

Claims

1. An electrical plug and socket arrangement comprising a plug with two or more pins and a cooperating socket with apertures for receiving the pins, wherein at least one of the pins of the plug includes a recessed region for receiving a cooperating member associated with the power supply switching mechanism of the socket, the arrangement being such that power can only be supplied to the plug when the plug is fully engaged in the socket and the member is engaged in the recess.

2. An arrangement according to claim 1, wherein the recess is provided in the earth pin of the plug.

3. An arrangement according to claim 1 or 2, wherein the switching mechanism comprises a slider switch linked rigidly to the member, the member being aligned with the position of the pin recess for sliding movement towards and away therefrom.

4. An arrangement according to claim 3, wherein the recess is located in the upper surface of the top pin of a plug, with the member peg in the form of a peg located for vertical sliding movement.

5. An arrangement according to any one of the preceding claims, based on a conventional domestic round or square pin plug with corresponding sockets.

6. An arrangement according to any one of the preceding claims, wherein the plug is produced by removing a pin from a conventional plug and substituting a notched pin.

7. An electrical plug and socket arrangement substantially as herein described with reference to, and as shown in, the accompanying drawings.