GB2278428A

GB2278428A - Lighting system having primary and auxiliary light sources and power supplies

Info

Publication number: GB2278428A
Application number: GB9310921A
Authority: GB
Inventors: Albert Henry Wilbourne
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-05-27
Filing date: 1993-05-27
Publication date: 1994-11-30
Anticipated expiration: 2013-05-27
Also published as: GB9310921D0; GB2278428B

Abstract

A lighting system comprises a primary light source 18 and an auxiliary light source 20 utilising an auxiliary power supply 32, for use when the power supply 14 to the primary light source 18 is interrupted, for example, in the event of a power-cut. The system is arranged such that interruption of the primary power supply 14 results e.g. in operation of a relay 30 to permit connection of the auxiliary power supply 32 and the auxiliary light source 20. <IMAGE>

Description

LIGHTING SYSTEM This invention relates to a lighting system, and in particular to a lighting system which provides an auxiliary light source on failure of a power supply to a primary light source.

Emergency lighting, for use in the event of a failure of the mains electricity supply, is provided in offices, public buildings and large apartment buildings. In many jurisdictions provision of such power supplies is mandatory, to assure the safety of occupants and to assist the emergency services. Such emergency lighting is provided with a separate, dedicated power circuit linked to an emergency power supply, which may be in the form of a generator or a battery stack. In certain buildings an emergency power supply may also be provided for other essential services, for example, hospitals are normally provided with generators on a controlled run up cycle to ensure continuity of electricity supply for incubator heating, life-support machines, theatre lighting and the like.

Despite the stress and inconvenience that may occur due to a mains electricity failure, private dwellings have not previously been provided with any form of emergency or auxiliary lighting. However, especially in remote areas, householders will often suffer power-cuts during which time they must rely on torches, candles, paraffin lanterns and the like as a source of light. Thus in the event of a power cut it is first necessary for the householder to locate the torch or candles, for example, in their unlit dwelling. Also, such light sources tend to provide only a limited amount of light, and in the case of a torch the light may only be provided for a limited time period, until the batteries are exhausted. Further, candles and lanterns pose a potential fire risk.

It is therefore an object of the present invention to provide an emergency or auxiliary lighting system which is suitable for use in the domestic environment and which obviates and mitigates the abovementioned disadvantages.

According to the present invention there is provided a lighting system comprising a primary light source and an auxiliary light source utilising an auxiliary power supply, for use when the power supply to the primary light source is interrupted, the arrangement being such that interruption of the primary power supply results in operation of switch means to permit connection of the auxiliary power supply and the auxiliary light source.

The invention may be utilised in domestic dwellings, or where permissible, in public or industrial premises, in order to provide auxiliary lighting in the event of a failure of the mains electricity supply. The invention has particular application for dwellings in remote areas with unreliable electricity supplies.

Preferably, on/off operation of the auxiliary light source is controlled by a further switch means. Most preferably, both light sources are controlled from a common switch means, such that during a power failure the normal light switch still controls operation of the room lighting. This arrangement also minimises the additional wiring and hardware necessary to implement the system.

Preferably also, the auxiliary power supply is provided by one or more electric cells. The cells may be rechargeable or may be non-rechargeable. Where rechargeable cells are provided, the cells may be connected to an auxiliary charging circuit linked to the primary mains supply via appropriate transformers and rectifiers. Typically, the cells will have sufficient capacity to provide a low voltage supply capable of providing auxiliary lighting for a period of at least three hours. Further, the ability to turn each auxiliary light on and off as desired tends to increase significantly the effective duration during which lighting is available.

Preferably also, the system is arranged to be accommodated in a ceiling rose fitting which may be connected to the existing, conventional lighting wiring, without requiring any modification thereto. Further, the room ceiling rose is usually the most effective point for lighting distribution and efficiency.

The switch means may be in the form of a relay, preferably a normally closed relay which is held in the open configuration when mains supply is available.

Alternatively, other forms of switch, either electro-mechanical, electrical or electronic, may be utilised.

A common primary and auxiliary light source may be utilised. Alternatively, dedicated light sources may be provided, in which case it is preferable to provide at least three auxiliary light sources, to assure that at least one auxiliary light source will function when called to do so.

According to a further aspect of the present invention there is provided a light fitting comprising a primary light source and an auxiliary light source and utilising an auxiliary power supply provided by one or more cells contained within the fitting, the arrangement being such that interruption of the mains power supply results in automatic operation of a switch to permit connection of the auxiliary power supply and the auxiliary light source, a common, manual switch controlling supply of power to both the primary and auxiliary light sources.

These and other aspects of the present invention will now described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a circuit diagram of a lighting system in accordance with a preferred embodiment of the present invention, illustrating the configuration of the circuit when mains electricity supply is present and the main light switch is open; Figure 2 shows the circuit of Figure 1 with the main light switch closed; Figure 3 shows the circuit of Figure 1 configured for a mains failure, with the main light switch open; and Figure 4 shows the circuit of Figure 1 configured for a mains failure, with the main light switch closed.

The drawings illustrate a circuit 10, the majority of which is contained within a light fitting in the form of' a ceiling rose, indicated by chain dotted line 12. External connections are provided for connection with a mains supply 14 and the circuit includes a main light switch 16.

The fitting 12 includes a primary socket and auxiliary sockets for receiving a conventional light bulb 18 and three lower voltage bulbs 20, respectively. The bulb 18 is connected to a primary circuit 22 which provides direct connection between the mains supply 14 and the bulb 18, whereas the auxiliary bulbs 20 may be linked to an auxiliary circuit 24.

In the illustrated example the mains supply is 240 V AC, whereas the auxiliary circuit 24 operates at 3.6 V DC. The stepping down is achieved by means of a transformer 26, and the auxiliary circuit includes two low voltage rectifier bridges 28. The auxiliary circuit 24 also includes a normally closed relay 30 which, when energised, in the presence of a mains supply, maintains a direct connection between the mains supply 14, the main switch 16 and the primary bulb 18, as shown in Figures 1 and 2.

The auxiliary circuit 24 also includes three rechargeable cells 32. While the mains supply is present, as shown in Figures 1 and 2, a current flows around the auxiliary circuit 24 to recharge the cells 32. The circuit 24 also includes an LED 34 which indicates red when the cells 32 are charging.

In this configuration the fitting 12 may be used as a normal light fitting, the primary bulb 18 being switched on and off as necessary at the switch 16.

In the event of a main supply failure, the energising current to the relay 30 is cut, such that the relay 30 assumes the position as shown in Figures 3 and 4 of the drawings, isolating the bulb 18 and connecting the auxiliary bulbs 20 to the auxiliary circuit 24, including the charged cells 32.

If the primary bulb 18 was switched on the smaller auxiliary bulbs 20 will immediately be illuminated to replace the bulb 18, and thus the householder will not experience sudden darkness. Also, to switch on the bulbs 20 during a power cut the householder simply uses the main switch 16, which he or she should be able to locate and operate without difficulty.

On reconnection of the main supply, the relay 30 returns to the configuration as shown in Figures 1 and 2, to allow energising of the primary bulb 18 as normal, and recharging of the cells 32.

It may be seen that the fitting 12 described above provides a very simple and effective auxiliary lighting system. Also, the fitting 12 may be utilised without the requirement to provide any specialised wiring arrangements.

It will be obvious to those of skill in the art that the above described embodiment is merely exemplary of the present invention and that various modifications and improvements may be made to the fitting 12 and the circuit 10 without departing from the scope of the invention, for example: in a simplified arrangement, the rechargeable cells 32 could be replaced with non rechargeable cells, such that the recharging circuit could be omitted.

Claims

1. A lighting system comprising a primary light source and an auxiliary light source utilising an auxiliary power supply, for use when the power supply to the primary light source is interrupted, the arrangement being such that interruption of the primary power supply results in operation of switch means to permit connection of the auxiliary power supply and the auxiliary light source.

2. The lighting system of claim 1 wherein on/off operation of the auxiliary light source is controlled by a further switch means.

3. The lighting system of claim 1 wherein on/off operation of both light sources is controlled by a common further switch means.

4. The lighting system of claim 1, 2 or 3 wherein the auxiliary power supply is provided by one or more electric cells.

5. The lighting system of claim 4 wherein the cells are rechargeable.

6. The lighting system of claim 5 wherein the cells are connected to an auxiliary charging circuit linked to the primary power supply via appropriate transformers and rectifiers.

7. The lighting system of claim 4, 5 or 6 wherein the cells have sufficient capacity to provide a low voltage supply capable of providing auxiliary lighting for a period of at least three hours.

8. The lighting system of any one of the preceding claims wherein the system is arranged for accommodation in a ceiling rose fitting and for connection to existing, conventional lighting wiring.

9. The lighting system of any one of the preceding claims wherein the switch means is in the form of a relay.

10. The lighting system of claim 9 wherein the switch means is in the form of a normally closed relay which is held in the open configuration when the primary power supply is available.

11. The lighting system of any one of the preceding claims wherein a common primary and auxiliary light source is provided.

12. The lighting system of any one of claims 1 to 10 wherein separate dedicated primary and auxiliary light sources are provided.

13. A lighting system substantially as described herein and as illustrated in the accompanying drawings.

13. The lighting system of claim 12 wherein at least three auxiliary light sources are provided.

14. A light fitting comprising a primary light source and an auxiliary light source and utilising an auxiliary power supply provided by one or more cells contained within the fitting, the arrangement being such that interruption of the mains power supply results in automatic operation of a switch to permit connection of the auxiliary power supply and the auxiliary light source, a common further switch controlling supply of power to both the primary and auxiliary light sources.

15. A lighting system substantially as described herein and as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows 1. A Lighting system comprising a primary light source and an auxiliary light source utilising an auxiliary power supply, for use when the power supply to the primary light source is interrupted, the arrangement being such that interruption of the primary power supply results in operation of switch means to permit connection of the auxiliary power supply and the auxiliary light source and where n on/off operatic of both light ,sources is controlled by a common further switch means, permitting the auxiliary light source to be switched both on and off after interruption of the primary power srnly.

2. The lighting system of claim 1 wherein the auxiliary power supply is providea by one or more electric cells.

3. The lighting system of claim 2 wherein the cells are rechargeable.

4. The lighting system of claim 3 wherein the cells are connected to an auxiliary charging circuit linked to the primary power supply via appropriate transformers and rectifiers.

5. The lighting system of claim 2, 3 or 4 wherein the cells have sufficient capacity to provide a low voltage supply capable of providing continuous auxiliary lighting for a period of at least three hours.

6. The lighting system of any one of the preceding claims wherein the system is arranged for accommodation in a ceiling rose fitting and for connection to existing, conventional lighting wiring.

7. The lighting system of any one of the preceding claims wherein the switch means is in the form of a relay.

8. The lighting system of claim 7 wherein the switch meals is in the form of a normally closed relay which is held in the open configuration when the primary power supply is available.

9. The lighting system of any one of the preceding claims wherein a common primary and auxiliary light source is provided.

10. The lighting syste of any one of claims 1 to 8 wherein separate dedicated primary and au:--iliary light sources are provided.

11. The lighting system of claim 10 wherein t least three auxiliary light sources, connected in parallel to the auxiliary power supply, are provided.

12. A light fitting comprising a primary light source and an auxiliary light source and utilising an auxiliary power supply rovided by one or more yells contained within the fitting, the arrangement being such that interruption of the mains power supply results in automatic operation of a switch to permit connection of the auxiliary power supply and the auxiliary light source, a common further switch controlling supply of power to both the primary and auxiliary light sources, permitting either the primary light source or the auxiliary light source to be switched on and off as desired.