Delayed power interruption alarm

An alarm device indicates the occurrence of a power failure or other interruption of power supplied to businesses or residences which triggers the alarm indication only after the elapse of a predetermined adjustable delay interval commencing upon the occurrence of the power failure. The device includes a mechanically-operated timer-alarm device, the operation of which is controlled by a lock and release lever, with the lever position in turn controlled by an electrically-operated solenoid plugged into the circuit to be monitored. As long as the circuit supplies power to the solenoid, release of the timer is prevented. Upon occurrence of a power failure, the release of the lock and release enables the timer to begin timing out intervals of a preselected duration, after which the alarm is sounded.

BACKGROUND DISCUSSION 
In many instances, it is highly important that homeowners and operators of 
commercial establishments be promptly made aware of the occurrence of a 
power failure since considerable damage or property loss may occur if the 
power failure continues for extended lengths of time. If the proprietor or 
homeowner is alerted, emergency power generating equipment could be 
pressed into service or other steps taken to reduce the incidence of 
damage or loss of perishables. 
These circumstances, for example, include the shutdown of refrigerators, 
freezers, and/or the interruption of service of sump pumps. If the power 
failure occurs at night, the homeowner may remain unaware of the power 
failure until a considerable lapse of time has transpired and the damage 
or loss already occurred. 
At the same time, many instances of interruption of service are relatively 
short in duration such that damage or loss would not occur and, 
accordingly, an alarm system for monitoring such failures would desirably 
not sound until after the failure has persisted for some time after which 
preventive steps should be taken. 
U.S. Pat. Nos. 4,001,803 and 3,958,212 both disclose typical prior art 
power failure alarms. These arrangements disclose a coil used to hold an 
alarm device in the inoperative position, which hold-in device is powered 
by the circuit to be monitored, thus upon interruption of the power, the 
alarm is sounded. 
However, this results in the sounding of the alarm for even momentary power 
interruptions such as to create unnecessary disturbances and the necessity 
to reset the device. Particularly, this is so since these interruptions 
could occur at relatively inconvenient times such as during the nighttime. 
An additional disadvantage of this approach is the necessity for an 
auxiliary power source, i.e., batteries, to power the alarm. Batteries 
degenerate with time and it is possible that the relatively long intervals 
of time during which the device would not get attention could very well 
lead to the failure of the device when needed. 
U.S. Pat. Nos. 3,588,856 and 1,999,811 disclose alarm arrangements for 
circuitry which incorporates delays. These appear to allow for a slight 
delay before the activation of the alarm device is produced and do not 
appear to interpose delays of sufficient duration to be applicable to the 
situation described above. In addition, these arrangements are relatively 
complex and not well suited to use by the homeowner. 
Accordingly, it is an object of the present invention to provide a power 
failure monitor or alarm which provides an alarm indication in the event 
of a power failure in the circuit to be monitored, but only after a 
predetermined adjustable delay of sufficient duration to eliminate giving 
false alarm conditions. That is, only upon continuance of the power 
failure or interruption for an interval of sufficient length is the alarm 
given such that steps may be taken to protect property endangered by the 
power failure. 
It is another object of the present invention to provide such a power 
failure monitor which does not depend on auxiliary power sources such as 
batteries, but which is self-contained so as to be relatively reliable in 
operation. 
It is yet another object of the present invention to provide such a power 
failure alarm which is simple and reliable in operation and which may be 
manufactured at relatively low cost. 
SUMMARY OF THE INVENTION 
These and other objects of the present invention, which will become 
apparent upon a reading of the following specification and claims, are 
achieved by the use of a mechanically-operated timer-alarm which sounds an 
alarm upon the elapse of a predetermined adjustable interval after 
activation of the timer. The actuation of the timer in turn is controlled 
by an electrical solenoid which serves to position a lock and release 
lever movable to a position to restrain release of the timer as long as 
power is supplied to the solenoid, but which is spring-biased outwardly to 
release the timer upon de-energization of the solenoid. The solenoid in 
turn is powered by the circuit being monitored such that upon the 
occurrence of a power failure, the solenoid is released and the lock and 
release lever moves to the release position and the timer begins to 
time-out.

DETAILED DESCRIPTION 
In the following detailed description, certain specific terminology will be 
utilized for the sake of clarity and a particular embodiment described in 
accordance with the requirements of 35 USC 112, but it is to be understood 
that the same is not intended to be limiting and should not be so 
construed inasmuch as the invention is capable of taking many forms and 
variations within the scope of the appended claims. 
Referring to the drawings, the alarm device 10, according to the present 
invention, includes a base plate 12 to which is mounted the various 
components. A cover or housing would normally enclose these, but is shown 
removed to reveal the details of the components. 
These components include a mechanically-operated, spring-wound timer-alarm 
14, electrical operator means including an electrical solenoid 16 and a 
pivoted lock and release lever 18. 
The solenoid 16 is linked to the lock and release lever 18 by a link 20 
joined at one end to the plunger 22 of the solenoid 16 and at the other 
end to one end of the lock and release lever 18. 
The lock and release lever 18 is pivoted at 26 such as to be rotated in a 
counterclockwise direction upon energization of the solenoid 16 to be 
maintained in the position shown in FIG. 1. This movement is against the 
bias of an extension spring 28 secured at one end to a mounting post 30 
and at the other end to a mounting opening 32 formed in the lock and 
release lever 18. 
The opposite end of the lock and release lever 18 is formed with a blade 
end 34 which is engaged with a gear 36 normally forming a part of the 
timer-alarm 14, such that as long as the lock and release lever 18 is in 
the position shown in FIG. 1, the timer-alarm 14 is prevented from 
operating. 
The timer-alarm 14 may be of a conventional design such as used for kitchen 
timers and comprises a selector handle 38, the rotation of which serves to 
allow adjustment of the predetermined time of operation of the timer-alarm 
14, since after release, the alarm is sounded only after the elapse of a 
predetermined interval. 
The solenoid 16 is maintained in an energized condition by the power cord 
40 which may be plugged into an A.C. outlet 42 in the circuit of which the 
power is to be monitored. 
Accordingly, if the power is interrupted in that circuit, the solenoid 16 
is released and the lock and release lever 18 rotated clockwise by the 
extension spring 28, moving the lock and release lever 18 to the release 
position. 
When power is restored in the circuit, the lock and release lever 18 is 
again moved to the position shown in FIG. 1 to arrest the movement of the 
gear 36 and prevent sounding of the timer-alarm 14. 
The homeowner or proprietor observing the lapse of a portion of the time 
may reset the timer-alarm 14 to allow the full delay period to be 
interposed after the next power failure. 
Accordingly, it can be appreciated that the objects of the invention have 
been achieved by this arrangement in that a delay of considerable and 
selected duration may be built into the alarm system to cause activation 
of the alarm only after delay of sufficient duration to present a hazard 
and which may be tailored to the particular situation encountered by the 
user requiring protection. The device relies only on a 
mechanically-operated timer-alarm and may remain inactive between 
intervals of relatively great duration while remaining operative, inasmuch 
as the device does not depend on batteries which may fail over long 
periods of nonuse. 
The extreme simplicity of this device is such that it may be manufactured 
at relatively low cost. 
It is noted that the device may also be utilized as a conventional kitchen 
timer merely by unplugging the solenoid and releasing the lock and release 
lever to enable use of the device as a conventional timer. 
Accordingly, during daytime hours when the power failure would be readily 
observed, the timer may be pressed into use in various kitchen or other 
applications and then plugged into the wall outlet for such use and 
continue to function as a power interruption monitor. 
It should also be understood that while the use of a conventional timer 
results in the advantages described above, other timer-alarm devices could 
be employed.