Fluorescent Fixture Auxiliary Light

Abstract

An auxiliary lighting unit for use with a fluorescent fixture of the type having a recessed ballast well is provided. The unit comprises a removable cover for the ballast well to which is mounted a self-contained power source and bulb connected to the power source. Switch means are provided which interconnect the power source and bulb. The switch means are normally held OFF but adapted to switch ON in the event of a disruption in the normal power supply to the fixture thereby enabling the auxiliary bulb to act as an emergency light. The unit may also include a photocell positioned to detect when the main light bulbs are turned off and to interconnect the emergency bulb and normal power supply at that time thereby enabling the auxiliary bulb to act as a night light.

Description

BACKGROUND OF THE INVENTION

The present invention relates to auxiliary lighting fixtures and more particularly to a lighting unit for use with a fluorescent fixture as an emergency or night light.

Emergency lighting systems are commonly used to provide limited illumination in the event of a disruption in normal electrical power service. Such systems usually utilize rechargeable batteries connected to a low wattage bulb through a relay which is held open by the normal flow of current from the main power supply. In the event of a disruption in the main power service, the relay closes thereby connecting the battery to the low voltage bulb and providing emergency lighting for as long as the battery lasts. To this end, during periods of non-use, the rechargeable battery itself is connected to the main power supply through suitable rectifiers and switches to insure that the battery is always properly charged.

Heretofore, emergency lights were either self-contained, separate and apart from the main lighting system or incorporated in special fixtures of the main system. While such systems are satisfactory for many purposes their principal drawback is that they are not flexible and do not readily permit rearrangement.

In view of the above, it is the principal object of the present invention to provide an emergency lighting unit adapted to be used with a conventional fluorescent lighting fixture to convert that fixture into an emergency light which may readily be moved from one fixture to another as may be required.

Another object is to provide a unit which can detect when the conventional fluorescent light bulbs are OFF and provide a night light at that time.

SUMMARY OF THE INVENTION

The above and other beneficial objects and advantages are attained in accordance with the present invention by providing an auxiliary lighting unit for use with a fluorescent lighting fixture of the type having a ballast well recessed in the rear of the fixture. The auxiliary unit comprises a cover plate for the ballast well adapted to be removably attached to the fixture. A self-contained power source is attached to the cover extending into the ballast well. A light bulb mounting socket is attached to the cover adapted to support a bulb toward the front of the fixture. Switch means interconnect the bulb socket and power supply and means are provided for normally holding the switch means OFF but adapted to turn the switch means ON in the event of a disruption in normal electrical service. The unit further includes an indicator mounted to the cover and readily visible through the fixture diffuser to give visible indication of the emergency light fixture. The indicator comprises a test switch operable through the diffuser to permit checking of the emergency unit without requiring any disassembling of the light fixture.

The unit may further include a second switch operable through a photoelectric cell to interconnect the emergency bulb with the main power supply. This enables the present auxiliary unit to act as a night light when the main lights are off.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is an environmental view of a fluorescent light fixture incorporating an auxiliary light unit in accordance with the present invention;

FIG. 2 is a bottom plan view of the fixture;

FIG. 3 is a sectional view taken along reference lines 3--3 of FIG. 1 in the direction indicated by the arrows;

FIG. 4 is a perspective view of the auxiliary lighting unit of the present invention; and

FIG. 5 is a circuit diagram for the auxiliary lighting unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference is now made to the drawings wherein similar components bear the same reference numeral throughout the several views. Accordingly, the present invention relates to an auxiliary lighting unit 10 adapted for use with a fluorescent fixture 12 of the type comprising a troffer 14 having a ballast well 16 recessed in the rear wall 18 of the fixture. The fixture 12 is a conventional fluorescent fixture having side walls 20 and rear wall 18 formed by the troffer and a diffuser plate 22 which extends across the troffer front. While this preferred embodiment will be described in connection with a fluorescent fixture having a troffer, it should be understood that the invention is equally applicable to many other types of fluorescent fixtures such as an industrial or surface mounted box or indeed any fixture having room therein for the additional hardware.

The diffuser plate 22 is supported by frame 24 which is hinged at 26 to provide access to the interior of the fixture to permit inserting and removal of the conventional fluorescent bulbs 28 mounted therein to appropriate sockets 30. A transformer 32 and the associated leads for electrical interconnection with the various sockets 30 are carried in the ballast well 16 along with the leads from the line voltage supply. Normally, well 16 is covered by a plate provided with slots and tabs that engage appropriate mating parts 34 formed in the rear of the troffer adjacent the well.

In accordance with the present invention, the conventional ballast well covering plate is replaced by the auxiliary lighting unit 10 which comprises an elongated member 36, V-shaped in section. The free edges of member 36 are provided with appropriate slots 38 and tabs 40 to engage the slots and tabs 34 of the fixture in the same manner as the conventional cover plate. Mounted to an exterior surface 42 of member 36 are a pair of spaced sockets 44 adapted to receive a low wattage bulb 46 therebetween and make appropriate electrical contact with the bulb. Generally, the rating of bulb 46 will not exceed 40 watts and the bulb will be rapid start.

Mounted to the surface 48 opposite surface 42 and extending toward the ballast well are the electrical components 50 associated with the present emergency lighting unit. These components include a transformer 52, rectifier 54 and rechargeable battery 56 and an inverter (if required which converts the output of the battery to AC. The transformer 52 is connected through leads 58 and 60 to the line voltage supply available in the ballast well for feeding bulbs 28. The battery 56 is connected to emergency lamp 46 through relay 59 which is also connected to the line voltage through leads 62 and 64. Relay 59 serves as a switch which is normally held OFF by an appearance of current on line 62 and 64. In the event of an absence of current on line 62-64, relay 59 switches ON thereby directly connecting lamp 46 with battery 56 so that the battery serves to light the lamp. At times when the battery is not being drained by lamp 46 it is constantly being charged from the line voltage through transformer 52 and rectifier 54. To this end, rectifier 54 may also include appropriate limiting circuitry to prevent overcharging and damage to the rechargeable batteries.

In addition to relay 59 tripping in the event of a power shortage, a test switch 66 is provided to manually trip the relay. As shown in FIG. 3, switch 66 includes a push button or detent 68 which rests on the diffuser panel 22. Since the diffuser panel 22 rides loosely in frame 24, it may readily be pushed upwardly to enable tripping of switch 66 without requiring opening of the frame. In addition, the detent 68 may be brightly colored so as to give ready indication of the emergency unit's presence in the fixture.

As previously stated, elongated member 36 is dimensioned to replace the conventional cover for ballast well 16 and engage the troffer in the same manner as the conventional ballast cover. Further, the only leads that need be connected to render the unit operational are 58 and 60. Thus, if for any reason the unit has to be removed from one lighting fixture to another, all that need be done is to electrically disconnect leads 58 and 60 from the power supply and mechanically disconnect tabs and slots 38 and 40 from the mating parts 34 of the troffer. The entire emergency unit may then be moved to another fixture where the existing ballast cover is removed and replaced by the present unit after leads 58 and 60 are appropriately connected.

Another feature of the present unit is a photocell 70 mounted to member 36 and sighting on fluorescent bulb 28. The photocell serves to control switch 72 to maintain the switch open wehn incident light reaches its active surface and to allow switch 72 to close when incident light is removed. The switch 72 is in one leg 74 of a circuit extending from the main power supply to bulb 46, the other leg of the circuit being lead 76. As long as bulb 28 remains lit, the photocell serves to keep open the circuit between the main power supply and emergency bulb 46. However, if the bulb 28 is turned off, switch 72 closes connecting the emergency bulb to the main power source thereby enabling the emergency bulb to serve as a night light which automatically goes on when the main lights are turned off. It should be apparent that leads 58, 62 and 76 may be connected to a single wire 78 and similarly leads 60, 64 and 74 may be connected to a single wire 80 so that the present unit can be fully installed electrically merely by connecting leads 78 and 80 to the main power supply.

Thus, in accordance with the above, the aforementioned objects and advantages are effectively attained.

Claims

Having thus described the invention, what is claimed is:

1. In a fluorescent fixture of the type adapted to be connected to a line voltage source to provide current to at least one conventional fluorescent light bulb and including means for connection to the line voltage source; a fixture rear wall; an open front section opposite the rear wall; a ballast well recessed in the rear wall; securing means formed in the rear wall; and a ballast well cover removably attached to the rear wall securing means overlying and covering the ballast well; the improvement comprising: an elongated cover member; securing means attached to said elongated cover member to mate with said rear wall securing means to removably secure said elongated cover member to said rear wall when said ballast well cover is removed from said rear wall; a self contained power source attached to said elongated cover member; light bulb mounting means attached to said cover member; switch means secured to said cover member and interconnecting said bulb mounting means and self contained power source, said switch means normally being held in an OFF position and adapted to switch to an ON position in the event of a disruption of said line voltage source so as to provide an auxiliary lighting unit which can readily be removed from one fixture for attachment to another fixture as required to convert the fixture to which it is attached to an emergency lighting fixture.

2. The invention in accordance with claim 1 wherein said fixture includes a diffuser plate overlying said fixture front section and further comprising indicator means connected to said cover and mounted in position to be visible through said diffuser plate.

3. The invention in accordance with claim 1 further comprising test circuit means connected to said switch means and manually operable to shift from a first, inactive position to a second position shifting said switch means to said ON position and disrupting a connection between said line voltage source and connection means.

4. The invention in accordance with claim 3 wherein said fixture includes a diffuser plate overlying said fixture front, said diffuser plate being shiftable to some degree from said fixture front toward the fixture rear, and said test means includes portions in engagement with said diffuser plate and adapted to move therewith whereby when said diffuser plate is shifted rearwardly, said test means shifts from said first to said second position.

5. The invention in accordance with claim 1 further comprising second switch means connected to said line voltage source, connecting means extending between said bulb mounting means and second switch means and adapted to be connected to said line voltage source through said second switch means.

6. The invention in accordance with claim 5 further comprising a photoelectric cell mounted to said cover to receive light from said conventional fluorescent light bulb, said photoelectric cell being in controlling relationship with said second switch means to maintain said second switch means open when incident light is received from said conventional bulb and to close said second switch means in the absence of incident light from said fluorescent bulb.