Abstrict A system for testing the electrical integrity of an illuminated
exit sign alternately powered by a battery, rechargeable from a
source of alternating current power. The system includes an alarm
for indicating an electrical failure, precluding the illumination
of the exit sign. A circuit tests the presence of battery electrical
power for illuminating the exit sign. In addition, the circuitry
periodically tests for the provision of adequate battery power to
achieve the same function. Moreover, the system periodically tests
and retests for adequate recharging of the battery during a preselected
period of time and includes an alarm for indicating failure of the
recharging system.
Claims What is claimed is:
1. A system for testing the electrical integrity of an exit sign
illuminated by a lamp, alternately powered by a battery rechargeable
from a source of AC power and powered by the AC power source; comprising:
a. alarm means for indicating an electrical failure precluding
illumination of the exit sign;
b. means for periodically testing for the presence of battery electrical
power to illuminate the exit sign, said alarm means indicating the
absence of battery power;
c. means for periodically testing for the provision of adequate
battery power to illuminate the exit sign, said alarm means indicating
inadequate battery power;
d. means for periodically testing for adequate recharging of the
battery during a preselected period of time, said alarm means indicating
the failure of the recharging of the battery; said means for periodically
testing for the presence of the battery power, said means for periodically
testing for the provision of adequate battery power, and said means
for periodically testing for adequate recharging of the battery
further comprise means for transferring the source of illumination
of the exit sign between the AC source and the battery; and
e. means for periodically testing for the existence of the lamp
and for the operation of said means for transferring the source
of illumination of the exit sign between AC source and the battery,
including a detector for a ripple voltage associated with the AC
source.
2. The system of claim 1 in which said alarm means comprises a
visual unit having distinctive signals to selectively indicate the
absence of battery power, inadequate battery power and failure of
the recharging of the battery.
3. The system of claim 1 in which said detector comprises a control
circuit, said control circuit includes a comparator for detecting
the presence of said ripple voltage at the output of said comparator.
4. The system of claim 3 in which said alarm means comprises a
visual unit having distinctive signals to selectively indicate the
absence of battery power, inadequate battery power, and failure
of the recharging of the battery.
5. The system of claim 4 in which said alarm means comprises a
light emitting diode.
6. The system of claim 4 in which said alarm means further comprises
a bicolor light emitting diode.
Description BACKGROUND OF THE INVENTION
The present invention relates to a novel and useful system for
testing the electrical integrity of an illuminated exit sign.
Illuminated exit signs are required by law to be placed in edifices
to indicate egress from a structure as a matter of convenience and
during periods of emergency. It is, thus, important that such exit
signs be reliable, being provided with a constant supply of electrical
power to maintain illumination of the exit signs at all times. Along
these lines, it is imperative that the integrity of the electrical
system of an illuminated exit sign be tested at selected intervals
to ensure that power is always available to the exit sign under
all conditions. That is to say, the existence of a battery, the
integrity of the battery, the charging system for the battery, and
the like, must constantly be determined.
In the past, many testing procedures for illuminated exit signs
have been accomplished manually by roving personnel. Written records
must also be kept of such visual inspections and tests for review
by legal entities having jurisdiction over such matters. Recently,
many rules and regulations have permitted the use of self-testing
and self-diagnostic illuminated exit signs operated by a battery,
in conjunction with limited visual inspections by personnel. Thus,
it is advantageous to provide illuminated exit signs that are capable
of accomplishing such self-tests.
U.S. Pat. Nos. 3384886 4088986 and 4544910 describe emergency
lighting and exit sign systems that include indicators showing the
existence of stand-by power, the proper level of voltage of the
stand by power and the integrity of a battery.
U.S. Pat. No. 4199754 shows a circuit for an emergency lighting
and fire detection system which latches an emergency light in an
off position indicating that a low voltage condition exists in the
battery power source.
An exit sign which is capable of continually self testing and retesting
source of battery power and recharging system for such battery would
be a notable advance in the emergency lighting field.
SUMMARY OF THE INVENTION
In accordance with the present invention a novel and useful system
for the testing of the electrical integrity of an illuminated exit
sign is herein provided.
The system of the present invention utilizes an exit sign that
is alternately powered by a battery or a source of alternating current,
which also is capable of recharging the battery. The exit sign includes
alarm means for indicating an electrical failure which would preclude
the illumination of the exit sign. Such alarm means may be a bi-color
indicator which is capable of emitting a steady light or a blinking
light, as the case requires.
Circuit means is included in the exit sign for periodically testing
the presence of a battery at certain time intervals. In other words,
the absence of battery power is determined during intervals. In
addition, means is provided for periodically testing the level of
battery power which is adequate to illuminate the exit sign. The
alarm means indicates either situation.
Further, the existence of source of lighting, such as an LED light
strip is also determined by the circuitry of the present invention.
Again, the alarm means would indicate by a certain color of light
or a particular pattern of light the existence or non existence
of the LED strip. In one embodiment of the invention, signal voltage
of a peculiar pattern is detected by comparator which is indicative
of the presence of the LED strip. If such peculiarly patterned signal
disappears, the alarm means would indicate the absence of an LED
strip.
Besides the existence and failure of the battery source for the
exit sign, the system of the present invention periodically tests
the charging system for the battery. That is to say, although a
battery may pass its end-of-life test, a subsequent test within
a short period of time after charging the battery may indicate a
failure. Usually this is interpreted as a charging system failure.
During most of the self-testing activities of the system of the
present invention a transfer function takes place in which illumination
of the exit sign occurs as a result of exchanging the alternating
current source for the battery source. The system of the present
invention also checks the integrity of such transfer system, which
is the basis of many of the tests herein above described. In other
words, the presence of the battery, power level of the battery,
and recharging of the battery of the exit sign will require the
functioning of the transfer system between the AC and DC power sources.
It may be apparent that a novel and useful system for the testing
of the electrical integrity of an illuminated exit sign is herein
provided.
It is therefore an object of the present invention to provide a
system for testing the electrical integrity of an illuminated exit
sign which is capable of testing for the existence of a battery
source of power, an adequate level of battery voltage, and recharging
system for the battery.
A further object of the present invention is to provide for a system
for testing the electrical integrity of an illuminated exit sign
which is capable of retesting the battery charging system and a
battery end-of-life function after a specific interval following
the initial tests of these functions to eliminate false signals.
A further object of the present invention is to provide a system
where the testing of the electrical integrity of an illuminated
exit sign eliminates many manual tests and reduces the cost of maintaining
exit signs in buildings.
Yet another object of the present invention is to provide a system
for the testing of the electrical integrity of an illuminated exit
sign which includes an alarm indicator having multiple visual cues
which are easily interpreted by the user.
A further object of the present invention is to provide a system
for the testing of the electrical integrity of an illuminated exit
sign which is highly reliable in an emergency situation.
The invention possesses other objects and advantages especially
as concerns particular characteristics and features thereof which
will become apparent as the specification continues. |