GB2563833A

GB2563833A - Electrical socket

Info

Publication number: GB2563833A
Application number: GB1710070.2A
Authority: GB
Inventors: Mcdermott Edward
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-04-25
Filing date: 2017-06-23
Publication date: 2019-01-02
Also published as: GB201706537D0; GB2561856A; GB201710070D0

Abstract

An electrical socket 10 configured for connection to an electrical supply and formed to receive an electrical plug and to supply it with electricity, the electrical socket comprises: a delay timer 30 configured to be triggered by an event indicative of commencement of electrical usage, to measure passage of a predetermined delay period, and, in the event that electrical usage does not cease during the delay period, to apply an activation signal to signalling device 32 configured, in response to the activation signal, to emit a visible and/or audible warning signal to alert a user; and/or to change the state of a switching element of the socket and so switch off electrical supply to the plug. The socket thus serves to alert users if a socket is left active for an excessive period of time and to cut-off electrical supply to prevent associated risks with leaving an electrical device unattended.

Description

ELECTRICAL SOCKET

The present invention concerns electrical sockets.

It is all too easy to forget an electrical device which has been plugged into the mains and left active. This can be wasteful of electricity, but more importantly some electrical devices can pose a danger if left active and unattended. Consider for example the risk posed by an electrical iron which could cause heat damage to their environment, or even fire if left on. Any of us is capable of such oversight but unattended electrical devices pose particular risks to certain groups including: - blind people; - those with memory loss; - children; - dementia sufferers; - students at residential educational institutions such as universities; - people with learning difficulties; - the elderly; and - those with certain disabilities.

The problem is experienced in domestic dwellings but also in shared residential institutions, for example hospitals and care homes, and in non-residential buildings such as offices, where there may be a failure for any individual to take responsibility for ensuring that devices are not left active, which can exacerbate the dangers posed.

One of the reasons for active electrical devices being left unattended and forgotten is that many devices provide little or no indication that they are active. For example many electrical irons have no visual or audible indicator to show the user that they are plugged into the mains supply and hence active.

There are various timer devices on sale which plug into a wall socket and which themselves provide a socket for receipt of a plug connected to an appliance being driven. Such devices are often used, for example, to switch an appliance such as an electric light on and off at fixed times in the day. The timer typically completes one full cycle during a 24 hour period and is active while the device itself is plugged into a wall socket. Such devices do not solve the above identified problem of unattended electrical appliances being left in a live condition.

The present invention is intended to provide a means of reducing the problems posed by unattended and/or forgotten active electrical devices.

In accordance with a first aspect of the present invention there is an electrical socket configured for connection to an electrical supply and formed to receive an electrical plug and to supply it with electricity, the electrical socket comprising a delay timer configured to be triggered by an event indicative of commencement of electrical usage, to measure passage of a predetermined delay period, and, in the event that electrical usage does not cease during the delay period, to: apply an activation signal to a signalling device configured, in response to the activation signal, to emit a visible and/or audible warning signal to alert a user and/or to change the state of a switching element of the socket and so switch off electrical supply to the plug.

In accordance with a further aspect of the present invention there is an electrical socket configured for connection to an electrical supply and formed to receive an electrical plug and to supply it with electricity, the electrical socket comprising a delay timer and a signalling device, the delay timer being configured to be triggered by an event indicative of commencement of electrical usage, to measure passage of a predetermined delay period, and, in the event that electrical usage does not cease during the delay period, to apply an activation signal to the signalling device at the end of the delay period, the signalling device being configured, in response to the activation signal, to emit a visible and/or audible warning signal to alert a user.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a front view of a mains electrical socket embodying the present invention; and

Figure 2 is a block circuit diagram of circuitry in the electrical socket.

Figure 1 shows a wall-mountable mains electrical socket 10, which in this particular example has a pair of sockets 12a, 12b, each provided with a respective switch 14a, 14b. The illustrated socket is for the domestic market in the United Kingdom and has a UK standard layout of three female ports for receipt of respective pins, these comprising a live port 16, a neutral port 18 and an earth port 20. The present invention may alternatively be implemented with any suitable electrical socket, which may be a 2-pin socket and may conform to the format used anywhere in the world. The socket is wired to a mains electrical supply through live and neutral lines indicated at L and N in Figure 2.

The socket 10 differs in external visible appearance from a conventional socket in having: a light cover 22; and a timer adjustment device 24.

The timer adjustment device 24 is used to adjust a delay period. The range of delays that can be set may differ from one embodiment to another but in the present example the user can set a period of between one and five minutes by turning an adjustment knob 26. In other embodiments the delay period may be from one to sixty minutes or from one to 99 minutes. A dial 28 behind the knob is marked to give the user an indication of the delay period that has been set. A digital device with a display could be used in place of the analogue knob and dial arrangement.

The socket 10 is configured to provide a warning signal in the event that either of the switches 14 is left in its "on" state for more than the pre-set delay period. Once activated the warning signal continues until the switches 14 are changed to their "off" state.

Figure 2 represents one possible circuit for this purpose, purely by way of example and not limitation. This drawing shows only a single switch 14 for the sake of simplicity, this being connected in the live electrical line L. The neutral line is of course connected to the neutral port 18 of the socket, and the live line is connectable via the switch 14 to the live port 16 of the socket, to supply mains electricity to a device plugged into the socket. The output side of the switch 14, and the neutral line, are also connected to opposite sides of a winding of a step-down transformer 28. Hence mains power is applied to the transformer 28 only when the switch 14 is "on" (i.e. when the switching contacts are closed).

In a practical arrangement the two switches 14a, 14b will be connected in parallel so that mains power is applied to the transformer when either of them is on.

The transformer 28 provides a step down in voltage from the mains voltage to a voltage suitable to drive the socket's electronics. In the present embodiment the transformer's output voltage is 12V, although this may differ in other embodiments. The transformer's output may also be rectified to provide the electronics with DC power.

Adelay timer 30 is connected to the output side of the transformer 28 and is configured to be activated upon receipt of electrical power. Hence the timer 30 is activated when the switch 14 is changed from "off" to "on". From the moment of its activation, the timer counts down the preselected delay period.

The timer controls a warning device 32. During the delay period after activation, the warning device 32 is maintained in an inactive state. When the delay period has elapsed, the timer 30 outputs a signal to the warning device 32 causing it to be activated. Switching off the electrical power to the timer 30 causes it to be reset, so that when next activated it will begin once more to count down the full delay period.

When active, the warning device 32 transmits a warning signal which is perceptible by a user. The warning signal in the present example comprises (a) a warning light provided by an LED 34 disposed behind the light cover 22, to radiate through it and (b) an audible alarm signal from a speaker or other sound emitter 36.

The warning signal may be continuous or it may be periodic. A periodic signal may become more frequent and/or longer in duration over the time for which the warning signal is active, so that if the warning signal evokes no initial response it becomes increasingly powerful in order to attract attention. In the present embodiment both the visual and the audible signals are pulsed, the initial pulse rate being adjustable between 5 seconds and 2.5 minutes, progressively shortening to 5 seconds over time.

To appreciate how the socket 10 functions in practice, consider what happens when a user plugs in an electrical device - an iron, say. The switch 14 is initially in the off state. The user switches it on and so activates the iron. This action also triggers the countdown timer 30, but initially no warning signal is emitted. If, within the pre-set delay period, the user turns off the switch 14, then no warning signal is needed and none is given. Power to the timer 30 ceases whereupon its countdown is reset.

If on the other hand the user fails to switch the socket off within the delay period then it may be that the user has for some reason forgotten that the iron is plugged in and active. To alert the user to possible danger, the warning signal is triggered at the end of the delay period. The signal continues, becoming progressively more insistent, until the warning signal attracts attention from a user and the socket's switch 14 is once more turned "off".

So the above described embodiment ensures that if the socket is left active for an excessive period, a warning signal will be delivered. In some situations this will be sufficient to ensure safety. In certain situations however there is the risk that no person will be able to perceive the warning signal, e.g. because the socket is in an unattended area, or because of the nature or disability of the user.

In a development of the above described embodiment, the socket 10 is additionally configured to disconnect mains electrical supply from the ports 16, 18 after the delay period has elapsed. In one such example, mains supply through the socket is switched off after the warning signal has been given, in the event that the user does not, within a second predetermined delay period, either reset the timer or switch off the socket. For this purpose, a switching element may be incorporated in the live mains line L which is configured to break the line when controlled to do so in response to the timer 30. The switching element may take the form of a mechanical relay in the live line L, or it may be a solid state switching device such as a field effect transistor.

The embodiments presented herein serve as examples and are non-limiting on the scope of the invention as set out in the appended claims. Numerous variants and alterations are possible. For example, the socket 10 may be configured to respond not to the state of the socket's switch 14, but to the supply of power to an external device. To this end, it may incorporate a current sensor configured to trigger and to cancel the timer 30. The current sensor may be an inductive device. In some embodiments the delay timer may be configured to provide a longer range of delay periods up to perhaps 30 minutes or an hour, making the device suitable for use as a timer, e.g. for use in the kitchen when cooking or for regulating usage of electronic devices by children under parental supervision.

Claims

1. An electrical socket configured for connection to an electrical supply and formed to receive an electrical plug and to supply it with electricity, the electrical socket comprising a delay timer configured to be triggered by an event indicative of commencement of electrical usage, to measure passage of a predetermined delay period, and, in the event that electrical usage does not cease during the delay period, to: apply an activation signal to a signalling device configured, in response to the activation signal, to emit a visible and/or audible warning signal to alert a user and/or to change the state of a switching element of the socket and so switch off electrical supply to the plug.

2. An electrical socket as claimed in claim 1 having a user operable control to adjust the delay period.

3. An electrical socket as claimed in claim 1 or claim 2 in which the electrical socket comprises a user-operable switch controlling supply of electrical power through the socket, the user-operable switch having an off state in which it prevents supply of electrical power and an on state in which it conducts electrical power, and delay timer being arranged to be triggered when the user-operable switch is changed from the off state to the on state.

4. An electrical socket as claimed in claim 3 in which the delay timer is configured to re-set when the user-operable switch is changed to the off state.

5. An electrical socket as claimed in any preceding claim in which the warning signal increases in volume, power or frequency over time.

6. An electrical socket as claimed in any preceding claim which is a wall-mountable mains socket.

7. An electrical socket as claimed in any preceding claim in which the switching element is controlled to switch off the electrical supply after a second predetermined delay period which commences upon issuance of the activation signal.

8. An electrical socket as claimed in any preceding claim in which the delay timer is configured to be triggered upon commencement of electrical supply through the socket.

9. An electrical socket as claimed in any preceding claim in which the switching element comprises a relay connected in a live electrical supply line of the socket.