Abstrict In lighting fixture such as an exit sign, a light emitting diode
lighting device is provided for mating engagement with an electrical
socket of the lighting fixture. The light emitting diode lighting
device has a plurality of light emitting diodes with a light directing
member spaced therefrom for directing light into a desired illumination
pattern. The light directing member can be wedge or parabola shaped.
Claims What is claimed is:
1. A lighting device for illuminating indicia of an exit sign having
an enclosure and a primary electrical power source, comprising:
(a) a housing;
(b) illumination means in said housing to be powered by the primary
electrical power source, said illumination means including a plurality
of light emitting diodes extending from said housing; and
(c) light directing means connected to paid housing and spaced
from said plurality of light emitting diodes for directing light
from said light emitting diodes into the enclosure to illuminate
the indicia of the exit sign.
2. The lighting device in accordance with claim 1 wherein said
light directing means has a wedge shape.
3. The lighting device in accordance with claim 1 wherein said
light directing means has a parabola shape.
4. The lighting device in accordance with claim 1 wherein said
light directing means is moveable relative to said light emitting
diodes to obtain various illumination patterns.
5. The lighting device in accordance with claim 1 wherein said
housing has two legs extending therefrom and said light directing
means extends between said two legs.
6. The lighting device in accordance with claim 5 wherein said
light directing means is connected to said legs for movement relative
to said light emitting diodes to obtain various illumination patterns.
7. The lighting device in accordance with claim 6 wherein said
light directing means is connected to said legs for pivotal and
rectilinear movement relative to said light emitting diodes.
8. The lighting device in accordance with claim 1 wherein said
plurality of light emitting diodes are mounted on a printed circuit
board.
9. The lighting device in accordance with claim 8 wherein said
housing has an enclosure therein in which said printed circuit board
is positioned.
10. The lighting device in accordance with claim 8 wherein said
printed circuit board is part of said illumination means.
11. The lighting device in accordance with claim 8 wherein said
printed circuit board has electrical components thereon for said
illumination means.
12. The lighting device in accordance with claim 1 further including
an emergency electric power supply in said housing to provide auxiliary
power to said light emitting diodes in the event of failure of the
primary electrical power source.
13. The lighting device in accordance with claim 12 wherein said
emergency electric power supply includes at least one rechargeable
battery, a charging device for keeping said at least one rechargeable
battery fully charged during periods of nonuse and circuit for switching
between said emergency electric power supply and the primary electrical
power source.
14. The exit sign in accordance with claim 1 further including
a rectifying circuit in said housing for rectifying electrical power
from the primary electrical power source into direct current for
powering said illumination means.
15. The exit sign in accordance with claim 1 further including
a mounting base assembly on said housing for electrically connecting
said illumination means to the exit sign, said mounting base assembly
matingly received in an electrical socket of the exit sign through
relative rotational and axial movement therebetween.
16. The lighting device in accordance with claim 15 wherein said
mounting base assembly permits orientation of said housing relative
to said mounting base assembly.
17. An exit sign connectable to a primary electrical power source,
comprising:
(a) a sign housing defining an enclosure therein and having indicia
to be illuminated;
(b) a primary electrical power circuit adapted to be connected
to the primary electrical power source;
(c) at least one lighting device electrically connected to said
primary electrical power circuit and positioned within said enclosure
for illuminating said indicia, each lighting device comprising:
(i) a lighting device housing having an enclosure,
(ii) illumination means in said lighting device housing, said illumination
means including a plurality of light emitting diodes extending from
said lighting device housing, and
(iii) light directing means connected to said housing and spaced
from said plurality of light emitting diodes for directing light
from said light emitting diodes into the enclosure to illuminate
said indicia of said sign housing.
18. The exit sign in accordance with claim 17 wherein said light
directing means has a wedge shape.
19. The exit sign in accordance with claim 17 wherein said light
directing means has a parabola shape.
20. The exit sign in accordance with claim 17 wherein said light
directing means is moveable relative to said light emitting diodes
to obtain various illumination patterns.
21. The exit sign in accordance with claim 17 wherein each said
lighting device housing has two legs extending therefrom and said
light directing means extends between said two legs.
22. The exit sign in accordance with claim 21 wherein said light
directing means is connected to said legs for movement relative
to said light emitting diodes to obtain various illumination patterns.
23. The exit sign in accordance with claim 22 wherein said light
directing means is connected to said legs for pivotal and rectilinear
movement relative to said light emitting diodes.
24. The exit sign in accordance with claim 17 wherein said plurality
of light emitting diodes are mounted on a printed circuit board.
25. The exit sign in accordance with claim 24 wherein said printed
circuit board is positioned in said enclosure of said lighting device
housing.
26. The exit sign in accordance with claim 24 wherein said printed
circuit board is part of said illumination means.
27. The exit sign in accordance with claim 24 wherein said printed
circuit board has electrical components thereon for said illumination
means.
28. The exit sign in accordance with claim 17 further including
an emergency electric power supply to provide auxiliary power to
said light emitting diodes in event of failure of the primary electrical
power source.
29. The exit sign in accordance with claim 28 wherein said emergency
electric power supply includes at least one rechargeable battery,
a charging device for keeping said at least one rechargeable battery
fully charged during periods of nonuse and circuit for switching
between said emergency electric power supply and the primary electrical
power source.
30. The exit sign in accordance with claim 28 wherein said emergency
electrical power supply is mounted within said lighting device housing.
31. The exit sign in accordance with claim 28 wherein said emergency
electric power circuit operationally connected to said primary electric
power circuit to detect failure of the primary electrical power
source and thereafter provided auxiliary power to said at least
one lighting device.
32. The exit sign in accordance with claim 17 further including
a rectifying circuit in said lighting device housing for rectifying
electrical power from the primary electrical power source into direct
current for powering said illumination means.
33. The exit sign in accordance with claim 17 a mounting base
assembly on said lighting device housing for electrically connecting
said illumination means to an electrical socket in said lighting
device housing, said mounting base assembly matingly received in
said electrical socket through relative rotational and axial movement
therebetween.
34. The exit sign in accordance with claim 33 wherein said mounting
base assembly permits orientation of said lighting device housing
relative to said mounting base assembly.
35. The exit sign in accordance with claim 17 wherein said at
least one lighting device is two lighting devices spaced from one
another within said enclosure to fully illuminate said indicia.
36. The exit sign in accordance with claim 35 wherein said two
lighting devices have their respective light emitting diodes facing
one another.
37. The exit sign in accordance with claim 35 wherein said two
lighting devices have their respective light emitting diodes facing
away from one another.
Description BACKGROUND OF THE INVENTION
The present invention relates generally to electrical lighting
sources and, more particularly, to electrical lighting sources in
illuminated exit signs.
Under current local fire and building codes, buildings to which
the public has access are required to have signage therein identifying
the exits. Most of these signs are required to exhibit a specific
amount of illumination and, oftentimes, must have an emergency backup
power source to provide emergency illumination to the light for
a specified period of time during periods when utility power to
the building is discontinued, thereby facilitating egress of persons
from the building.
Traditionally, two 15-watt incandescent lamps driven by 120 volt
alternating current (120 VAC) have been employed to provide normal
illumination while two 3.6-watt incandescent lamps driven by a self
contained emergency battery power supply are used for illumination
during power failure situations. A switching or transfer device
will automatically operate the emergency backup illumination system
when a power failure is detected.
While these traditional exit sign lighting arrangements perform
adequately, they do have a few drawbacks. A major drawback is that
the incandescent bulbs use large amounts of electric power thus
requiring a relatively large emergency battery power supply for
use during emergency lighting situations. Furthermore, while the
incandescent bulbs provide adequate illumination, such bulbs do
not have a long life in service and require frequent replacement.
To alleviate the drawbacks associated with incandescent bulbs,
many manufacturers are beginning to utilize light emitting diodes
(LEDs) rather than incandescent bulbs in exit signs. Each light
emitting diode provides a relatively small amount of light as compared
to the traditional incandescent bulbs whereby a large number of
light emitting diodes must be used to provide the same amount of
illumination offered by the traditional incandescent bulbs.
It is an object of the present invention to provide a novel lighting
device for an exit sign using a plurality of light emitting diodes.
It is also an object to provide such a lighting device which allows
the light emitting diodes to be powered by both the normal utility
electrical power (120 VAC) and, during emergency power situations,
an emergency battery power supply and associated charging and transfer
circuitry.
Still another object is to provide such a lighting device in which
the light emitting diodes are arranged in the exit sign to provide
the amount of illumination required by building codes.
A further object is to provide such a lighting device which may
be readily and economically fabricated and will enjoy a long life
in operation.
SUMMARY OF THE INVENTION
It has now been found that the foregoing and related objects can
be readily attained in an exit sign connectable to a primary electrical
power source and having a sign housing, a primary electrical power
circuit and at least one lighting device. The sign housing defines
an enclosure therein and has indicia to be illuminated. The primary
electrical power circuit is adapted to be connected to the primary
electrical power source and is electrically connected to the at
least one lighting device. The at least one lighting device is positioned
within the sign housing enclosure for illuminating the indicia.
Each lighting device has a lighting device housing which defines
a lighting device enclosure. A plurality of light emitting diodes
extend from the lighting device housing. A light directing member
is spaced from the plurality of light emitting diodes for directing
light from the light emitting diodes into the enclosure to illuminate
the indicia of the sign housing. The light directing means can have
a wedge or parabola shape.
In order to obtain a variety of illumination patterns, the light
directing member is moveable relative to the light emitting diodes.
To space the light directing member from the light emitting diodes,
the lighting device housing has two legs extending therefrom and
the light directing member extends between the two legs. The light
directing member is connected to the legs for pivotal and rectilinear
movement relative to the light emitting diodes to obtain the variety
illumination patterns.
According to the invention, the plurality of light emitting diodes
are mounted on a printed circuit board positioned in the enclosure
of the lighting device housing. The printed circuit board is electrically
connected to and has electrical components for the plurality of
light emitting diodes
Desirably, the exit sign has an emergency electric power supply
to provide auxiliary power to the light emitting diodes in event
of failure of the primary electrical power source. The emergency
electric power supply is at least one rechargeable battery and includes
a charging device for keeping the at least one rechargeable battery
fully charged during periods of nonuse. The emergency electrical
power supply is mounted within the lighting device housing or outside
the lighting device housing inside the exit sign housing. The emergency
electric power supply is operationally connected to the primary
electric power circuit to detect failure of the primary electrical
power source and thereafter provided auxiliary power to the at least
one lighting device.
Ideally, a mounting base assembly is provided on the lighting device
housing for electrically connecting the light emitting diodes to
an electrical socket in the lighting device housing. The mounting
base assembly is matingly received in the electrical socket through
relative rotational and axial movement therebetween. The mounting
base assembly permits orientation of the lighting device housing
relative to the mounting base assembly.
Preferably, the at least one lighting device is two lighting devices
spaced from one another within the enclosure to fully illuminate
the indicia. The two lighting devices can have their respective
light emitting diodes facing one another or can have their respective
light emitting diodes facing away from one another.
The invention will be fully understood when reference is made to
the following detailed description taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of an exit sign housing with
portions removed and broken away to illustrate internal structure
including two light emitting diode lighting devices made in accordance
with the first embodiment of the present invention;
FIG. 2 is a perspective view of one of the light emitting diode
lighting devices from the exit sign of FIG. 1;
FIG. 3 is a cross-sectional view of the light emitting diode lighting
device taken along the 3--3 line of FIG. 2 and illustrating the
adjustability of the wedge reflector in phantom line;
FIG. 4 is an exploded perspective view of the light emitting diode
lighting device of FIG. 2;
FIGS. 5 and 6 are illustrations of the illumination pattern of
the exit sign of FIG. 1 as viewed from above;
FIGS. 7 and 7A are an electrical schematic for the exit sign of
FIG. 1;
FIG. 8 an exploded perspective view of an alternative arrangement
for the light emitting diode lighting device of FIG. 2 which has
electronic circuitry mounted therein;
FIG. 9 side elevational view of an exit sign housing with portions
removed and broken away to illustrate internal structure including
two light emitting diode lighting devices as shown in FIG. 8;
FIG 10 is a perspective view of a second embodiment of the light
emitting diode lighting device of the present invention which uses
a parabola shaped reflector;
FIG. 11 is a perspective view of the parabola shaped reflector
of the second embodiment of the light emitting diode lighting device
as shown in FIG. 10;
FIG. 12 is a cross-sectional view of the second embodiment of the
light emitting diode lighting device taken along the 12--12 line
of FIG. 10;
FIG. 13 is a side elevational view of an exit sign housing with
portions removed and broken away to illustrate internal structure
including two light emitting diode lighting devices according to
the second embodiment of the invention as shown in FIG. 11; and
FIGS. 14 and 15 are illustrations of the illumination patterns
of the exit sign of FIG.13 as view from above.
DETAILED DESCRIPTION OF THE INVENTION
Referring first to FIG. 1 of the drawings, therein illustrated
is an exit sign generally designated by the numeral 10. The exit
sign 10 is mountable to both a canopy bracket (not shown) and a
standard electrical junction box (not shown) in a manner explained
in copending U.S. patent application Ser. No. 07/925313 U.S. Pat.
No. 5272605 entitled CANOPY MOUNTING DEVICE FOR EXIT SIGNS AND
THE LIKE. With this arrangement, the exit sign construction of this
invention can be mounted directly to a standard electrical junction
box found in a ceiling or wall of a building in any desired location.
The exit sign 10 comprises a central rectangularly shaped frame
12 with front and back cover members 14 and 16 at least one of
which incorporates a large stencil 18 having the letters "EXIT"
in the major surface thereof and a colored plastic diffuser 20 therebehind.
The central rectangularly shaped frame 12 and the front and back
cover members 14 and 16 are snap-fit together and cooperate to form
a housing having an enclosure 22 containing the necessary internal
electrical lighting components. The front and back covers 14 16
can use a plurality of finger clips (not shown) to hold them in
assembly with the central rectangularly shaped frame 12. The exit
sign 10 is preferably molded from a plastic resin such as an engineering
type thermoplastic such as ABS, polycarbonate or polyphelyene oxide
but it should be apparent to those skilled in the art that they
may be manufactured from other suitable materials.
The enclosure 22 of the exit sign 10 is divided into a wiring compartment
24 and a lighting compartment 26 by a retaining wall 28 which extends
around the interior sides and top of the central rectangularly shaped
frame 12. In a manner explained further hereinafter, the wiring
compartment 24 contains an appropriate wiring harness 30 and battery
power pack module 32 for powering two 1-watt direct current light
emitting diode lighting devices 34 held by standard screw type lamp
sockets 36 extending downwardly into the lighting compartment 26
from an upper part of the retaining wall 28.
Referring to FIGS. 2-4 taken in conjunction with FIG. 1 each of
the light emitting diode lighting devices 34 has an elongated plastic
housing 38 having a pair of parallel legs 40 extending from one
side thereof which each have an elongated slot 42 defined therein.
Positioned between the legs 40 is a moveable wedge member 44 having
pins 46 on either end thereof. The pins 46 mount in the elongated
slots 42 to permit the wedge member 44 to move toward and away from
the plastic housing 38 and rotate around the axis of the pins 46
as illustrated in FIG. 3. Inside the elongated plastic housing 38
is a printed circuit board 48 with a plurality of light emitting
diodes 50 thereon. The light emitting diodes 50 are positioned to
extend toward the wedge member 44 from a plurality of apertures
52 in a pedestal portion 54 of the elongated plastic housing 38.
The wedge member 44 is designed to direct light rays 56 from the
light emitting diodes 50 in an appropriate illumination pattern
as shown in FIGS. 5-6 to provide full illumination for the stencil
18. Through cooperation of the pins 46 and the slots 42 the wedge
member 44 can be rotated and also moved toward and away from the
light emitting diodes 50 to make appropriate adjustments to the
illumination pattern for the stencil 18. The plastic housing 38
and the wedge member 44 are made of or coated with a reflective
material so as to provide the proper amount of illumination.
As illustrated in FIGS. 1 and 5-6 in order for light rays from
the light emitting diode lighting devices 34 to evenly illuminate
the stencil 18 when they pass through the diffuser 20 the light
emitting diode lighting devices 34 with the light emitting diodes
50 therein have to face one another. To obtain this type of alignment,
the light emitting diode lighting devices 34 are provided with mounting
base assemblies 58 (one shown in FIG. 4) which permit adjustment
of the elongated rectangular plastic housings 38 relative to the
mounting base assemblies 58 once the assemblies 58 are fully inserted
and tightened into their respective screw-type lamp sockets 36.
The adjustment of the elongated rectangular plastic housings 38
relative to the mounting base assemblies 58 is described in U.S.
Pat. No. 5416679 entitled MOUNTING BASE ASSEMBLY FOR A LIGHTING
DEVICE USED IN AN EXIT SIGN by inventors Charles R. Ruskouski and
James J. Burnes, which is hereby incorporated by reference, particularly,
FIGS. 3 and 4 and the description thereof.
Turning now to FIGS. 7 and 7A taken in conjunction with FIG. 1
to power the light emitting diode lighting devices 34 the utility
power (120 VAC) is provided to the wiring harness 30 through electrical
leads (not shown) which extend into an electrical junction box (not
shown) found in the ceiling or wall of the building. The battery
power pack module 32 is electrically connected to the wiring harness
30 and incorporates a battery charger and converter circuit 60.
The circuit 60 is designed in a manner well known to those skilled
in the art to rectify the utility power into direct current and
charge an auxiliary rechargeable battery pack 62. The circuit 60
also is designed to switch between the primary alternating current
power supply and the emergency direct power supply provided by the
rechargeable battery pack if the alternating current power supply
fails as would be the case during a utility power outage.
During normal operation, utility power on the wiring harness 30
energizes the light emitting diodes 50 and maintains a charge on
the battery pack 62 and, during emergency operation when the utility
power fails, the battery pack 62 energizes the light emitting diodes
50 until utility power resumes on the wiring harness 30.
When the utility power is supplied on the wiring harness 30 the
alternating current is first passed through a current limiting resistor
R1 and capacitor C1 and is then passed through a bridge circuit
BR1 which rectifies the alternating current into direct current.
If the utility power fails, the current in the capacitor C1 discharges
through the resistor R1 to prevent electrical shocks. The direct
current from the bridge circuit BR1 initially flows through a Zener
diode D1 and energizes a coil K1 for closing contacts Ca and Cb
and opening contacts Cc and Cd so that the battery pack 62 is connected
in series with the coil K1 and the light emitting diodes 50 which
are electrically connected in series, parallel or series parallel
to one another. This maintains the closure of the contacts Ca and
Cb, charges the battery pack 62 and energizes the light emitting
diodes 50. At this point, no current flows through the Zener diode
D1.
When the utility power is not supplied on the wiring harness 30
the coil K1 is deenergized, which opens the contacts Ca and Cb and
closes the contacts Cc and Cd. This causes the battery pack 62 to
discharge through a boost regulator circuit 64 (shown in detail
in FIG. 9A) which boosts the battery voltage to a level sufficient
to operate the light emitting diodes 50. For example, when the utility
power is off, the direct current flows from the positive side of
the battery pack 62 through the contact Cc, into point a and out
point b of the boost regulator circuit 64 where the output voltage
Vb is greater than the input voltage Va. The direct current then
flows through the light emitting diodes 50 which are electrically
connected across points b and c as shown, into point c and out point
d of the boost regulator circuit 64 through the contact Cd and
back to the negative side of the battery pack 62.
The boost regulator circuit 64 is well known in the art and one
example is shown in FIG. 7A. It has an input voltage Va coupled
to pin 1 of a DC-to-DC converter IC1 and to one side of an inductor
L1. The other side of the inductor L1 is coupled to a drain of a
FET transistor Q1 having its gate coupled to pin 6 and its source
coupled to ground. A Schottky diode D3 is connected between the
drain of the FET transistor Q1 and an output voltage Vb. In operation,
the direct current passes into the boost regulator circuit 64 at
point a discharges through the inductor L1 and the diodes D2 and
D3 and passes from the boost regulator circuit 64 at point b to
the light emitting diodes 50. The inductor L1 the DC-to-DC converter
IC1 the FET transistor Q1 the diodes D2 and D3 combined to boost
the output voltage Vb so it is greater than the input voltage Va
needed to provide the direct current to the light emitting diodes
50. Upon return from the light emitting diodes 50 the direct current
passes into the boost regulator circuit 64 at point c, through a
resistor R2 and passes from the boost regulator circuit 64 at point
d. From there, the direct current passes through the contact Cd
and back to the negative side of the battery pack 62 to complete
the circuit. The Zener diode D4 fixes the voltage at pin 5 of the
DC-to-DC converter IC1. A capacitor C4 filters out undesirable voltage
surges at point c of the boost regulator circuit 64 pin 3 is a
ground connection for the convertor IC1 and pin 8 is grounded since
it is not being used.
Turning now to FIGS. 8-10 therein is illustrated an alternative
mounting arrangement for the electronic circuitry of the present
invention. In this alternative arrangement, essentially all components
are identical to the arrangement in FIGS. 1-7A and like components
have been designated with like reference numerals except for the
addition of the reference character A.
As shown in FIG. 8 a circuit board 48A is mounted inside an elongated
plastic housing 38A and incorporates an appropriate battery charger
and converter 60A designed in a manner well known to those skilled
in the art (see FIGS. 7 and 7A) to rectify the alternating current
and to charge an auxiliary rechargeable battery pack 62A as well
as to switch between the primary alternating current power supply
and the emergency direct power supply provided by the rechargeable
battery pack 62A if the alternating current power supply fails as
would be the case during a utility power outage. The rechargeable
battery pack 62A is also arranged inside the elongated plastic housing
38A. As shown in FIG. 9 with two light emitting diode lighting
devices 34A, each having their own circuit 60A and battery pack
62A, the battery power pack module 32 of FIG. 1 can be eliminated.
Turning now to FIGS. 11-15 therein is illustrated a second embodiment
of the light emitting diode lighting device of the present invention.
In this second embodiment, essentially all components are identical
to the arrangement in FIGS. 1-7A and like components have been designated
with like reference numerals except for the addition of the reference
character B. The difference between the first and second embodiments
is the substitution of a parabola member 66 for the wedge member
44. As shown in FIG. 12 the parabola member 66 is moveable in the
same manner as the wedge member 44.
Referring to FIGS. 13-15 in order to accommodate the different
reflective capabilities of the parabola member 66 verses the wedge
member 44 the light emitting diode lighting devices 34B are aligned
with their light emitting diodes 50B pointing away from one another.
Light rays 56B captured in the parabola members 66 are directed
to illuminate the stencils 18B.
With regard to powering the light emitting diode lighting device
34B, it will be appreciated by those skilled in the art that the
second embodiment can be powered in the same manner as the first
embodiment, i.e., externally with battery pack module (FIGS. 7 and
7A) or internally (FIG. 8).
It will therefore be seen from the above that the present invention
provides an effective light emitting diode lighting device within
an exit sign. The exit sign using the light emitting diode lighting
devices has the same amount of illumination as found in exit signs
using traditional incandescent lamps while at the same time greatly
reducing power consumption.
It will thus be seen that the objects set forth above, among those
made apparent from the preceding description, are efficiently attained
and, since certain changes may be made in the above product without
departing from the scope of the invention, it is intended that all
matter contained in the above description or shown in the accompanying
drawings shall be interpreted as illustrative and not in a limiting
sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the invention which, as
a matter of language, might be the to fall therebetween.
|