Fixture for mounting a lampholder and fire detector

A combined light and fire detector fixture mountable on a recessed electrical box having a housing, mounting means to mount the housing to the electrical box, a light fixture having lamp holding means, mounting means for mounting the light fixture to the housing and electrical conducting means for coupling the lamp holding means to a switch and an alternating current power source, and fire detecting means including smoke or heat sensing elements and being mounted to the outside of the housing to provide easy access thereto and to decrease the heat generated within the housing and electrical box.

BACKGROUND OF THE INVENTION 
This invention relates generally to lighting fixtures and fire detectors, 
and more particularly to a combined light fixture and fire detector for 
simultaneous mounting on a recessed electrical outlet box. 
The concept of combining a lighting fixture and fire detector has been 
shown in at least two patents, specifically, U.S. Pat. Nos. 4,090,178 to 
Norris and 4,255,746 to Johnson, et al. The patent to Johnson, et al. 
discloses a home safety unit which includes an emergency light system and 
a fire detection system, wherein the lighting fixture is fixed to the 
outside of a housing and the fire detection system is mounted within the 
same housing. The smoke detector and light fixture disclosed in the Norris 
patent is similar in that the fire detector is concealed within a housing. 
An alternate embodiment disclosed in the Norris patent situates the smoke 
detecting element of the smoke detector at a distance from the electrical 
box by means of an electrical conduit, thereby requiring an additional 
hole to be cut in the ceiling. 
The shortcomings of the fixtures disclosed in the Johnson, et al. and 
Norris patents should be readily apparent to one of ordinary skill in the 
art. These shortcomings include the requirement that additional holes be 
provided in the housing to permit detection of smoke by the fire detecting 
element. Further, since the smoke detecting means is mounted within the 
housing, maintenance and repair of the same becomes difficult, as this 
would require removal of the lamp diffuser, the lamp and the housing 
itself. More importantly, such maintenance and repair can only be safely 
accomplished by cutting off the main power source and disconnecting the 
leads of the fixture from the leads of the electrical box, so as to gain 
access to the smoke detection means. 
Further, electrical devices of this type must meet certain minimum 
standards under the applicable building and electrical codes, or the more 
stringent standards of an independent testing organization, as is 
desirable when placing such a device into the commercial marketplace. Such 
standards normally require heat and electrical tests at different points 
about the lighting or other electrical fixture, at least one of such 
points exists within the electrical outlet box or within the housing of 
the type shown in the aforementioned patents. Thus, placement of the fire 
detecting means within a housing will have an adverse affect upon these 
heat and electrical tests, as more heat will be generated and trapped 
therein. 
In providing fire safety systems, it is often desirable to provide fire 
detectors having a heat sensing element in addition to or in place of a 
smoke detecting element, since the heat generated by a fire might be 
detected before the smoke. The devices disclosed in Norris and Johnson, et 
al. do not provide an adequate design to include heat sensing elements 
because the heat generated within the housing and electrical box might 
trigger the heat sensing element under normal operating conditions. 
As building and fire codes become more stringent, it is desirable to 
provide a combined light and fire detector fixture which can be directly 
mounted onto a recessed electrical outlet box and cures the above-noted 
shortcomings of the prior art fixtures. 
Accordingly, the present invention provides a single fixture for mounting a 
fire detector and a lamp holder to a single recessed electrical outlet 
box, which single fixture can be readily mounted in residential dwellings 
by homeowners or in any other setting, new or old, by an experienced 
builder or electrician. The use of conventional lighting fixtures and fire 
detectors facilitates the commercial practicability underlying the present 
invention. 
SUMMARY OF THE INVENTION 
The present invention covers a single fixture adapted to secure both a 
light fixture and a smoke or heat detector to a single recessed electrical 
outlet box in a ceiling or a wall, having a housing assembly with mounting 
means provided thereon, lamp holding means connected to the housing 
assembly and fire detecting means connected to the outside of the housing 
assembly and including an audible or visual alarm mechanism and a smoke 
detecting or heat sensing element for triggering said alarm mechanism upon 
detection of fire. The light fixture and the fire detector means both 
include conducting means coupled to the same alternating current power 
source, the fire detecting means further including battery means for 
operating the same when the power source is turned off or fails due to a 
power failure or other error. 
Accordingly, it is an object of the present invention to provide a combined 
light and fire detector fixture which can be readily mounted by a 
homeowner or experienced electrician to a single recessed electrical 
outlet box. 
It is another object of the present invention to provide a combined light 
and fire detector fixture where the fire detector is mounted on the 
outside of the fixture thereby avoiding the introduction of additional 
heat within the fixture and the electrical outlet box. 
It is another object of the present invention to provide a combined light 
and smoke detector fixture where simple repairs and maintenance of the 
fire detecting means can be accomplished without demounting the fixture 
from the electrical outlet box or turning off the main power source. 
It is yet another object of the present invention to provide a combined 
light and fire detector fixture where the fire detecting means includes a 
rechargeable battery means to energize the same, should the alternating 
current power source fail. 
These and other objects will become apparent, as will a better 
understanding of the concepts underlying the present invention, by 
reference to the description which follows when taken in conjunction with 
the accompanying drawings:

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, FIGS. 1-3 illustrate the preferred embodiment of 
the combined light and fire detector fixture generally designated as 10 in 
accordance with the present invention. 
The combined light and fire detector fixture includes a housing 11 made of 
sheet metal or any other suitable material and having an exterior surface 
12 and an interior 13 defined by side wall 14 which extends 
perpendicularly from, and about the perimeter of, the exterior surface 12. 
The housing further includes a centrally located mounting means 15, 
comprised in the illustrated embodiment of a threaded member having a 
decorative cover 16 to maintain the aesthetics of exterior surface 12, and 
one aperture for mounting the light fixture and a second aperture 31 to 
provide through access for the leads of the fire detector. 
The fixture 10 further includes a light fixture generally designated as 17 
and having a canopy 18 with light fixture mounting means 19 and a lamp 
base 20. The canopy 18 can be stamped from a sheet of metal or any other 
suitable material. The lamp base 20 is preferably made from a ceramic 
material, is cylindrically shaped and includes a metal screw shell 21 
riveted to the interior thereof. Lamp leads 22 and 23 are connected, by 
soldering or the like, to metal screw shell 21 and are adapted for 
connection to an alternating current (hereinafter AC) power source or 
circuit. 
An incandescent lamp 24, of the A-type or the R-type is threaded into screw 
shell 21, thus providing the conductive contacts to the filaments of lamp 
24 which will emit light by glowing when the AC power is on. The lamp can 
be of virtually any wattage up to 100 W. A round glass diffuser 25 is 
disposed about lamp 24 and is held in place by thumb screws 26a, 26b and 
26c, each of which is threadedly disposed through bushings 18a, 18b and 
18c of canopy 18 to engage diffuser 25 and secure the same in assembled 
position. Diffuser 25 could include a flared lip at its upper end (not 
shown) which will facilitate the securing thereof by said thumb screws. 
Diffuser 25 can be of any shape or size to meet particular light 
requirements or decor. 
The fire detecting means of fixture 10 generally designated as 27 in the 
drawings is mounted, as shown in FIG. 1, to the housing 11 by means of 
sheet metal screws 28a and 28b which have been threaded through exterior 
surface 12 and bushings, and protrude into interior 13. Of course, any 
suitable means can be used to mount fire detecting means 27 to fixture 10. 
The fire detector 27 is comprised of base 27a, which houses the detector 
circuitry and rechargeable battery means, and detector cover 27b to 
enclose such circuitry and provide a pleasing aesthetic appearance. The 
fire detector leads 28, 29 and 30 from the fire detecting means 27 extend 
through aperture 31 in housing 11 for connection to an AC power source 50. 
Lead 29 is connected to the fire detecting means 27 to operate the smoke 
detecting element or heat sensing element (not shown) and audible or 
visual alarm mechanism (not shown), while lead 30 is connected to the fire 
detecting means 27 to operate test light 32, as shown in FIG. 2, and lead 
28 provides the ground for the circuitry of the fire detecting means 27. 
It is imperative to note that the fire detector 27 of the present invention 
is typical of smoke or fire detectors which are commercially available in 
the marketplace, the fire detector 27 of the present invention being 
particularly adapted for use with an AC power source 50 and further 
providing a rechargeable battery (not shown) in the event of a power 
failure of course, the fire detector 27 of the present invention is 
provided with means for recharging the rechargeable battery and rectifying 
means to permit the operation of the fire detector 27 by AC power or 
direct current (hereinafter DC). 
Further reference to FIG. 2 reveals test button 33 on fire detector 27 
which can be depressed to light test light 32 thereby indicating that the 
power and/or circuitry of detector 27 is in operating condition. Also 
shown in FIG. 2 are holes 34 in detector cover 27b to expose the smoke 
detecting element or heat sensing element to the ambient conditions. 
Referring specifically to FIG. 3, the manner in which the fixture 10 is 
mounted can be readily observed. Thus, an electrical outlet box 35 is 
recessed within a ceiling defined by wallboard 36. Electrical conduit 37 
carries the two conductor lines of the household power from a fuse box or 
breaker switch, while electrical conduit 38 carries conductor lines to a 
switch. Thus, conductors 39, 40, 41 and 42 are exposed in electrical 
outlet box 35 for connection to lamp leads 22 and 23 of light fixture 17 
and fire detector leads 28, 29 and 30 of fire detector 27, as shown in the 
schematic of FIG. 3A. 
The schematic in FIG. 3A specifically shows that fire detector 27 
continually receives the alternating current, as leads 29 and 30 are 
connected to the "hot" conductor 41 from the AC power source 50 and lead 
28 is connected to the "ground" therefor. The light fixture 17, however, 
is operated in conjunction with switch 51, as lead 23 is connected to both 
conductor 39 (to the switch 51) and conductor 41 (to the AC power source 
50), and the lead 22 is connected to conductor 40 (to the switch 51). Of 
course, this circuitry can be modified so that the light fixture 17 can be 
operated by a pull chain instead of switch 51. 
It is preferable, during installation, to insert a sheet of insulation (any 
suitable type) into interior 13, as shown in FIG. 3. This insulation 
includes hole 52a in the center thereof for the threaded number 15 to 
extend therethrough. 
Once such connections are made, threaded member 15 of housing 11 is 
threadedly inserted into threaded hole 43a of mounting bracket 43 which is 
secured to electrical outlet box 35 by means of fasteners 44a and 44b. 
In operation, lamp 24 is lighted when the switch 51 is closed to permit the 
AC power 50 to travel to the light fixture 17, and fire detector 27 is 
continuously operated by such AC power 50. If, however, the AC power 50 to 
electrical box 35 is terminated by means of a power failure, the 
rechargeable battery system of fire detector 27 will be activated to 
maintain the fire detector 27 in the smoke detecting or heat sensing mode. 
Of course, it is possible to operate lamp 24 as well as fire detector 27 by 
means of a DC power service. 
Referring to FIG. 4 of the drawings, an alternate embodiment of the present 
invention is illustrated. In this embodiment, the combined light and fire 
detector fixture is particularly adapted for a fluorescent lighting 
system. 
Thus, fixture 110 of this alternate embodiment includes a fluorescent lamp 
124 secured to the housing 111 by spring clips 124a, 124b and 124c. Of 
course, fluorescent lamp 124 is electrically connected to a ballast (not 
shown) which can be disposed in the interior of housing 111 near the 
peripheral wall. It is preferable to employ a ballast which is P-rated so 
that heat shielding is not required and a ore efficient operation is 
obtained. 
In this embodiment, fluorescent lamp 124 is tubular in cross-section and 
circular in shape thereby permitting the installation of fire detector 127 
in the center of fixture 110. An elongated bracket 143 is utilized to 
mount fixture 110 to the recessed electrical box or ceiling. 
The operation of this alternate embodiment is identical to that described 
above with respect to the first embodiment. 
Thus, a combined light and fire detector fixture mountable on a single 
electrical outlet box and which need not be removed for repairs and 
maintenance of the fire detector, as well as providing other desirable 
features, has been described. 
While the foregoing description and figures illustrate one preferred 
embodiment of the combined light and fire detector fixture in accordance 
with the present invention, it should be appreciated that certain 
modifications such as the use of a fluorescent lighting system may be made 
in the structure and operation of the disclosed embodiment without 
departing from the spirit and scope of the present invention as defined by 
the claims which are set forth immediately below.