Emergency Lighting Equipment

Abstract

This invention is concerned with an emergency lighting system that does not require the normal modification of building wiring that is required by conventional emergency lighting systems presently available. The apparatus of this invention also lends itself to selective programing to meet special requirements of some emergency lighting installations.

Description

BACKGROUND OF THE INVENTION

When emergency lighting equipment is installed in buildings which have already been built without it and fixtures are employed where the battery, converter, and battery charging equipment are installed in the fixture, it is necessary to add an additional power line to each fixture in order that the battery remains on charge even when the wall switch is turned off. Such rewiring involves large expense and inconvenience. With the system described herein such rewiring is unnecessary.

SUMMARY OF THE INVENTION

This invention relates to emergency lighting systems and, more particularly, to emergency lighting systems that do not require modification of the standard building wiring.

The apparatus of this invention comprises a light fixture and associated wall switch box. The light fixutre is a conventional type light fixture, such as a fluorescent light fixture that has been modified to include the apparatus of this invention. Similarly, the wall switch box is of conventional design but modified in accordance with this invention.

The apparatus of this invention can, of course, be installed in a building during construction of the building or can be installed any time after the building has been erected. No matter when the apparatus is installed, the wiring requirement is the same as that required by regular non-emergency lighting systems.

In addition to providing typical emergency lighting, the apparatus of this invention lends itself to selective programing to provide special operative requirements that may be necessary in a given installation. For example, some prior art emergency lighting systems automatically turn on all the lights provided in the system when the main power goes off and the system is operating on emergency power. The lights are turned on regardless of whether or not the light was turned on when the main power failed. In some cases, for example a photographic darkroom, such operation may not be desirable or may even be detrimental. With the apparatus of this invention the emergency lighting system can be programed to avoid such automatic operation.

DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram showing one embodiment of the invention.

FIG. 2 is a block diagram showing a second embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 show two preferred embodiments of the invention in block diagram form. Block diagrams are used to illustrate these embodiments because all of the circuit elements or devices are conventional elements or devices available on the market.

Referring now to FIG. 1, the wall switch box 12 contains a switch 13 and a rectifier 11. Rectifier 11 receives AC power from an AC supply 10 and converts the AC to DC of the same value. The DC power is transmitted to the lighting fixture 14 through the power lines 15.

The polarity of the two lines of power line 15 to fixture 14 is dependent on the on-off position of wall switch 13. Switch 13 is a double-pole double-throw polarity reversing switch having a first pair of contacts 53 and a second pair of contacts 63. As can be seen from FIG. 1, the polarity of power lines 15 depends on whether switch 13 is closed on contacts 53 or 63. One of these positions is the "on" position and the other is the "off" position. As will be apparent later either position can be the "on" or "off" position.

The lighting fixture 14 contains a DC -- DC converter 16 which steps down the DC voltage received from wall box 12 via lines 15 and delivers the proper charging voltage to the battery 17. The output of battery 17 is applied to a DC to AC inverter 18 which steps up the DC voltage from the battery to an AC value sufficient to ignite the lamps 19. Lamps 19 may for example be fluorescent or high voltage lamps.

Power lines 15 are also connected to a polarity sensing device 20 which senses the polarity of the lines 15. Polarity sensing device 20 has its output connected to an "on-off" control device 21 which in turn has its output connected to DC - AC inverter 18.

The apparatus just described operates in the following manner: AC power supply 10 which would normally be the local commercial supply provides AC power to full wave rectifier 11. Rectifier 11 converts the AC voltage to a DC voltage having the same value as the AC voltage. This DC voltage is transmitted to converter 16 to a polarity sensing device 20 provided that switch 13 is closed on either pair of contacts 53 or 63. Converter 16 steps down the voltage at its input to provide a proper output voltage for charging battery 17. While converter 16 is conventional DC -- DC converter, it must be of the type that provides the proper polarity at its output for charging battery 17 regardless of the polarity of the input lines to the converter. This type of converter is necessary since a DC voltage is applied to converter 16 when switch 13 is closed on either contacts 53 or 63. It is particularly noted that this charging feature is one of the important features of the invention. Battery 17 receives a charging current even if switch 13 is in the off position. In the conventional emergency lighting systems additional wiring is used to provide charging current to the stand-by power supply. These prior art systems do not provide charging through the wall switch and normal wiring. Additional wiring is used for the charging circuit.

Polarity sensing device 20 senses the polarity of the lines 15 and provides a control signal to control device 21. The nature of the control signal is determined by the polarity of power lines 15. On-off control device 21 senses the signal from sensing device 20 and turns inverter 18 either "on" or "off" as the case may be.

For a more clear understanding of the operation of devices 20 and 21, assume that switch 13 is in the "on" position when it is closed on contacts 53 and is in the "off" position when closed on contacts 63. Then if switch 13 is closed on contacts 53, polarity sensing device 20 senses the polarity as indicated in FIG. 1 and transmits an "on" signal to on-off control device 21. On-off control device 21 will then turn "on" inverter 18 and lamps 19 will be lit. As was mentioned above inverter 18 steps up the voltage to the proper value necessary to energize lamps 19. If on the other hand, switch 13 is closed on contacts 63 (the "off" contacts), polarity sensing device 20 senses that the polarity of lines 15 is now opposite that which it was when switch 13 was closed on contacts 53 and provides an "off" signal to control 21. In response to this signal control device 21 turns inverter 18 "off" and lamps 19 are extinguished.

As was mentioned above, the "on-off" positions of switch 13 can be either of the two closed positions of this switch. This should now be obvious from the preceeding description of the operation of polarity sensing device 20 and "on-off" control device 21. Once the "on-off" positions of switch 13 have been selected, then sensing device 20 and control device 21 merely need to be properly connected to provide the desired operation for the "on-off" polarities of line 15 that result from the "on-off" positions chosen for switch 13.

The operation as thus far described taken place as long as AC supply 10 is functioning. Note, however, that even when AC power is available, lamps 19 are energized from battery 17 through inverter 18. AC supply 10 merely provides charging voltage to battery 17 and control voltage to polarity sensing device 20. If now AC supply 10 should fail, battery 17 is still available to provide voltage to lamps 19. Battery 17 remains at full charge when AC supply 10 is functioning. When the AC supply 10 fails, the polarity sensing unit 20 maintains sufficient voltage on lines 15 to maintain the polarization of the lines 15.

Thus the polarity sensing device 20 will still receive the control information from the wall box switch 13 and still be in control of the lights 19 as previously described under operation when there is no power failure In this manner the light will function identically during power failure and when there is no power failure, being at all times controlled by the all switch 13.

The system of FIG. 1 can be programmed to have other responses during power failures if such is desired. For example, control device 21 can be so programmed that it automatically turns on inverter 18 when supply 10 fails. In fact control device 21 can be programmed to provide various different types of control to meet any specific requirements of a particular installation.

From the foregoing description, it is obvious that the emergency lighting system of FIG. 1 provides an emergency system that can be readily installed in an existing building as well as in a building under construction. The installation can be made without using any wiring other than that normally used to install a lighting system. In conventional prior art emergency lighting systems, additional wiring is used to provide continual charging of the standby battery supply and control of the system during failure of the main supply. Control of the system and charging of the standby battery supply in the emergency lighting system of FIG. 1 is accomplished without the use of additional wiring.

The embodiment of the invention shown in FIG. 2 is somewhat more complex than the system shown in FIG. 1 and provides a highly versatile emergency lighting system that not only has general utility as an emergency lighting system but can also be used to provide any special operation features that may be required in a given installation. The system of FIG. 2 comprises a wall switch box 34 and a lighting fixture 42.

Wall switch box 34 houses a signal combination unit 31, a switch 33 and an encoding device 32 connected between combination unit 31 and switch 33. An AC supply 30 which will normally be the available commercial supply is connected to combination unit 31.

Lighting fixture 42 contains a power processor 36; a battery 37 connected to the output of power processor 36; an inverter the ballast 38 connected to a second output of power processor 36; the lamps 39 connected to the output of inverter and ballast 38; a control code monitor 40; and the controllers 41 connected to power processor 36, battery 37, monitor 40 and inverter and ballast 38. Power lines 35 connect signal combination unit 36 of wall switch box 34 to power processor 36 and control code monitor 40 of lighting fixture 42.

When AC power supply 30 is functioning properly, signal combination unit 31 receives an AC voltage from supply 30. Encoding device 32 applies a signal to combination unit 31 that is indicative of the condition of switch 33. That is, encoding device 32 provides information signals that indicate whether switch 33 is "on" or "off." These information signals are combined with the AC voltage from supply 30 and the combined voltage is transmitted to processor 36 and monitor 40 via lines 35. Processor 36 conditions the power supplied via lines 35 to the proper values to charge battery 37. Processor 36 provides a charging current to battery 37 if switch 33 is "on" or "off." The charging function is not sensitive to the code from encoding unit 32.

Monitor 40 is sensitive to the code signals from encoding unit 32 and provides an information signal to controllers 41 indicating the position of switch 33. If switch 33 is in the "on" position, controllers 41 in response to the signals from monitor 40 will cause processor 36 to deliver power from lines 35 to the inverter and ballast 38. Lamps 39 will thus be energized. Converseley, if switch 33 is in the "off" position, controllers 41 in combination with processor 36 will prevent the passage of the power to inverter and ballast 38.

If power supply 30 should fail, no AC voltage from supply 30 will be applied to combination unit 31. However, encoding device 32 will continue to provide code signals indicative of the "on-off" position of switch 33 to processor 36 and monitor 40. Monitor 40 is responsive to the code signals from encoding unit 32 and provides an output signal that indicates the "on-off" position of switch 33 and the fact that these code signals appeared on lines 35 without the AC voltage from supply 30. Thus, monitor 40 senses the power failure and the code signals and passes this information on to controllers 41. If switch 33 is in the "on" position at the time of failure of supply 30, monitor 40 will sense this condition and pass this fact on to controllers 41. Controllers 41 will then cause processor 36 to pass the voltage from battery 37 to inverter and ballast 38. Controllers 41 will also turn "on" the inverter of inverter and ballast 38. The inverter provides a stepped-up AC voltage from the DC at its input. This AC voltage is applied to the ballast to turn "on" lamps 39. If switch 33 is "off" when the power supply 30 fails, encoding unit 32 passes this information on to monitor 40 which in turn passes this information on to controllers 41. Controllers 41 provide the necessary control to the inverter of inverter and ballast 38 and to power processor 36 to keep lamps 39 turned "off." Note that if switch 33 is turned "on" after a failure of supply 30, this fact will be indicated by the code from encoding unit 32 and the lamps will be energized in the manner described above when switch 33 was "on" at the time of the failure of supply. In other words, switch 33 can be used to turn lamps 39 "on" and "off" under normal conditions and under emergency conditions.

In addition to the operation just described, encoding unit 32, monitor 40 and controller 41 can be programmed to provide any type of special operation or operations of the lighting system that a particular installation may require. For example, the lamps 39 can be automatically turned "on" in case of failure of supply 30 regardless of the position of switch 33, or the system can be operated such that the lamps are turned "on" or "off" by switch 33 only during emergency operation or only during normal operation, etc.

As was the case in FIG. 1, the standby battery 37 of FIG. 2 receives a charging current from power supply 30 regardless of the position of switch 33. However, in the FIG. 2 system, the condition of battery 37 is monitored by controllers 41 and the charging is controlled by controllers 41. While mentioned previously, it is again noted that all of the elements or devices of the FIG. 2 system are conventional elements or devices and are all available on the market.

While the invention has been described with reference to specific embodiments, it will be obvious to those skilled in the art that various changes and modifications can be made to the embodiments shown and described without departing from the spirit and scope of the invention as set forth in the claims.

Claims

What is claimed is:

1. An emergency power supply comprising: a switch box; an AC voltage source; a light fixture having at least one lamp and a battery; means to charge said battery from said AC voltage source through said switch box, said means to charge said battery through said switch box including a full wave rectifier housed within said switch box and connected to said AC voltage source, a switch housed within said switch box, a DC to DC converter, means to connect said switch between said full wave rectifier and said converter and means to connect said converter to said battery; and means to selectively energize and de-energize said at least one lamp when said AC voltage source is operative and when said AC voltage source is inoperative.

2. An emergency power supply as defined in claim 17 wherein said switch is a double-pole double-throw switch having an "on" position and an "off" position, said double-pole double-throw switch being so connected between said DC to DC converter and said full wave rectifier that said battery is charged from said AC voltage source when said switch is in said "off" position and when said switch is in said "on" position.

3. An emergency power supply as defined in claim 2 wherein: a polarity sensing device is connected to said double-pole double-throw switch; a DC to AC inverter is connected between said battery and said at least one lamp; and an "on-off" control device is connected between said DC to AC inverter and said polarity sensing device.

4. An emergency lighting system as defined in claim 3 wherein said selective energization and de-energization of said at least one lamp is controlled by said "on-off" control device in response to signals from said polarity sensing device.

5. An emergency power supply comprising: a switch box; an AC voltage source; a light fixture having at least one lamp and battery; means to charge said battery from said AC voltage source through said switch box; a signal combination unit housed in said switch box and connected to said AC voltage source; a switch and encoding unit housed in said switch box; means to connect said encoding unit between said switch and said signal combination unit; and means to selectively energize and de-energize said at least one lamp when said AC voltage source is operative and when said AC voltage source is inoperative.

6. An emergency lighting system as defined in claim 5 wherein said lighting fixture in addition to said battery and said at least one lamp includes a control code monitor, controllers coupled to said battery and said control code monitor; a power processor coupled to said battery and to said controllers, an inverter and ballasts coupled to said at least one lamp, to said controllers and to said power processor; and wherein means are provided for coupling said power processor and said control code monitor to said signal combination unit.

7. An emergency power supply as defined in claim 6 wherein said means for charging said battery includes said signal combination unit and said power processor.

8. An emergency power supply as defined in claim 7 wherein the condition of said battery is monitored by said controllers and the rate of charging said battery is controlled by said controllers.

9. An emergency power supply as defined in claim 8 wherein said encoding unit provides an output signal indicative of the "on-off" position of said switch and said control code monitor provides a control signal to said controllers in response to said signal from said encoding unit.

10. An emergency power supply as defined in claim 9 wherein said controllers provide a control signal to said power processor to energize said at least one lamp from said AC power through said power processor when said switch is in the "on" position and provides a signal to said power processor to block the voltage of said AC power supply from said at least one lamp when said switch is in the "off" position.

11. An emergency power supply as defined in claim 10 wherein said control code monitor senses a failure of said AC power supply and provides a signal to said controllers that indicates the said failure of said AC power supply in addition to the "on-off" position of said switch.

12. An emergency power supply as defined in claim 11 wherein said controllers provide a signal to said power processor and a turn-on signal to the inverter of said inverter and ballasts to energize said at least one lamp from the voltage of said battery when said AC power supply fails and said switch is in its "on" position.

13. An emergency power supply as defined in claim 12 wherein said control code monitor and said controllers are programmed to provide desired selective operation of said at least one lamp from both said AC supply and from said battery.

14. An emergency power supply as defined in claim 3 wherein said polarity sensing device and said "on-off" control device are programmed to provide programmed selective energization and de-energization of said at least one lamp.

15. An emergency power supply as defined in claim 3 wherein said at least one lamp when energized is energized by the voltage from said battery when said AC power supply is operating and when said AC power supply fails.