U.S. patent number 3,705,401 [Application Number 05/225,401] was granted by the patent office on 1972-12-05 for electrical alarm system.
Invention is credited to Francis A. Scott.
United States Patent |
3,705,401 |
Scott |
December 5, 1972 |
ELECTRICAL ALARM SYSTEM
Abstract
A plurality of protected stations connected by transmission
lines to a central monitoring station. Each protected station has a
condition sensing device capable of transmitting an abnormal
condition signal to the monitoring station where all the protected
stations are simultaneously monitored by a master signal detector.
The monitoring station also has an individual signal detector and a
selector switch so that an abnormal condition signal from any
particular protected station may be monitored by the individual
detector in exclusion of all the other protected stations which are
monitored by the master detector.
Inventors: |
Scott; Francis A. (Daytona
Beach, FL) |
Family
ID: |
22844718 |
Appl.
No.: |
05/225,401 |
Filed: |
February 11, 1972 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
851895 |
Aug 21, 1969 |
|
|
|
|
Current U.S.
Class: |
340/515;
340/691.5; 340/502; 340/517; 340/521; 340/525; 340/535; 340/566;
340/593; 340/692 |
Current CPC
Class: |
G08B
26/006 (20130101) |
Current International
Class: |
G08B
26/00 (20060101); G08b 019/00 () |
Field of
Search: |
;340/412,258R,261,276,148 ;179/1R,1H,1MN |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Caldwell; John W.
Assistant Examiner: Mooney; Robert J.
Parent Case Text
This application is a continuation-in-part of my earlier filed
pending application Ser. No. 851,895, filed Aug. 21, 1969 now
abandoned.
Claims
What is claimed is:
1. An electrical alarm system, comprising a plurality of protected
stations and a remote monitoring station connected to all of the
protected stations by transmission lines, each of the protected
stations including a condition sensing device capable of
transmitting a signal along said lines to said monitoring station
when an abnormal condition exists at the protected station, a
master signal detector provided at the monitoring station and
simultaneously monitoring the sensing devices of all the protected
stations, an individual signal detector at the monitoring station,
and a selector switch at the monitoring station for transferring
from said master detector to said individual detector an abnormal
condition signal originating at any particular protected station,
whereby that particular protected station may be monitored by the
individual detector in exclusion of all the other protected
stations which continue to be monitored by said master
detector.
2. The system as defined in claim 1 together with a plurality of
indicator lamps provided at said monitoring station and energizable
by abnormal condition signals from the respective protected
stations, said selector switch being manually actuated and having a
plurality of settings corresponding to the respective protected
stations, whereby an abnormal condition signal from a particular
protected station as indicated by its respective lamp may be
transferred from said master detector to said individual detector
by an appropriate setting of said manually actuated selector
switch.
3. The system as defined in claim 1 which is further characterized
in that said condition sensing device of at least one of the
protected stations is responsive to sound and transmits an abnormal
condition signal to said monitoring station when sound at that
protected station reaches a predetermined threshold level.
4. The system as defined in claim 1 which is further characterized
in that said condition sensing device of at least one of the
protected stations is responsive to temperature and transmits an
abnormal condition signal to said monitoring station when
temperature at that protected station reaches a predetermined
degree.
5. The system as defined in claim 1 which is further characterized
in that said condition sensing device of at least one of the
protected stations is responsive to a manually actuated switch and
transmits an abnormal condition signal to said monitoring station
when said last mentioned switch is actuated.
6. An electrical alarm system comprising a plurality of protected
stations and a central monitor station connected to all of the
protected stations by transmission lines, each of the protected
stations including means for producing audio frequency electrical
signals, and means for coupling said audio frequency electrical
signals to said transmission lines for transmission to said central
monitor station; said central monitor station including a master
loudspeaker for simultaneously monitoring the audio signals from
all of the protected stations, an individual loudspeaker for
individually monitoring the audio signals from only one protected
station at one time, a multiposition selector switch, said selector
switch having a standby position, means at said standby position
for connecting audio frequency signals from all of said protected
stations to said master loudspeaker while excluding all the audio
frequency signals from said individual loudspeaker, a plurality of
site positions corresponding in number to the number of protected
stations, means at each of said site positions for singly
connecting audio frequency signals from the protected station
corresponding to said selected site position to said individual
loudspeaker and for simultaneously connecting the audio frequency
signals from all of the protected stations exclusive of the
selected protected station to said master loudspeaker, and means
provided at said monitoring station for coupling the audio
frequency signals from each of said protected stations to said
multiposition selector switch.
7. The apparatus set forth in claim 6 wherein said audio frequency
producing means at each of said protected stations includes at
least one sound transducer for picking up sounds produced in the
region of the protected station.
8. The apparatus set forth in claim 7 wherein said audio frequency
producing means also includes an audio frequency oscillator, and at
least one means for keying said oscillator when an abnormal
condition occurs in said protected station.
9. The apparatus set forth in claim 8 wherein there are plural
diverse means for keying said oscillator, each keying means being
responsive to a different abnormal condition and keying said
oscillator in accordance with a preselected code indicative of the
abnormal condition to which said keying means responds.
10. The apparatus set forth in claim 9 wherein at least one of said
keying means includes a rotary periodic switch encoder in circuit
with an abnormal condition sensing switch and a power supply for
energizing said oscillator, said abnormal condition sensing switch
being normally open in the absence of an abnormal condition and
being closed upon the occurrance of an abnormal condition whereupon
energy from said oscillator power supply is intermittently applied
to said oscillator through said encoder in accordance with a
predetermined code pattern.
11. The apparatus set forth in claim 7 wherein said sound
transducer is a microphone and wherein said means for coupling said
audio frequency signals from said sound transducer to said
transmission lines is a coupling transformer having a centertapped
secondary winding, each protected station further having an audio
amplifier interposed between said microphone and said coupling
transformer, a power supply for energizing said audio amplifier and
microphone, an audio noise generator in circuit with said amplifier
power supply and a normally open relay switch, said normally open
relay switch having an energizing coil in circuit between said
center-tapped secondary winding and ground, said monitor station
further having a grounded power source for energizing the coil of
said relay switch in each remote station through said transmission
lines and circuit means for separately connecting said grounded
power source to the transmission lines between each protected
station and said monitor station including a test lamp means in
each circuit means for indicating the operative condition of the
protected station, and a test switch means paralleling said test
lamp for applying a sufficient energy from said grounded power
source to said relay coil when said test switch is closed to
activate said relay switch whereupon said noise generator is
energized to produce sound in said protected station which is
picked up by said sound transducer and monitored in said monitor
station.
12. The apparatus set forth in claim 6 together with a plurality of
indicator lights at the monitoring station, there being one
indicator light for each protected station, separate audio
frequency signal responsive means at said monitoring station for
each protected station for energizing the indicator light
associated with a particular protected station when an audio
frequency signal above a preselected threshold level is received
and for deenergizing said indicator light when the audio frequency
signal falls below said threshold level.
13. The apparatus set forth in claim 12 together with an audible
alarm in normally open circuit with all of said indicator lights,
said multiposition selector switch having means at said standby
position for closing said normally open circuit between said
audible alarm and said indicator lamps so that said audible alarm
will sound whenever one of said indicator lights is energized.
14. The apparatus set forth in claim 6 wherein said selector switch
is a multideck rotatable switch having multiple equally spaced
fixed contacts circularly arranged on each deck, one deck having an
annular rotatable conductor of smaller diameter than the inside
diameter of the circle of contacts in said one deck, an arcuate
segment extending radially outwardly from said annular conductor
for separately engaging one of the fixed contacts at a selected
position of said selector switch, a fixed brush in continuous
engagement with said annular conductor and circuit means connected
to said brush for transmitting signals from said brush to said
individual loudspeaker, the fixed contacts of said one deck at said
site positions being individually connected to receive audio
frequency signals from one of the protected stations so that when
said arcuate segment engages any one of the fixed contacts in said
plural site positions, audio frequency signals appearing at the
selected site position will be applied through said annular
conductor and said brush to said individual speaker, a second deck
having an annular rotary conductor interrupted by a narrow gap of
arcuate length less than the distance between two adjacent fixed
contacts on said second deck, means associated with each fixed
contact in the site positions of said selector switch for wiping
said interrupted annular conductor, a fixed brush in engagement
with said interrupted annular conductor and circuit means connected
to the fixed brush on said second deck for transmitting signals
from said brush to said master loudspeaker, the fixed contacts on
said second deck at said site positions each being individually
connected to receive audio frequency signals from one of the
protected stations, the gap on said interrupted annular conductor
being in the same angular position as the arcuate segment extending
from the annular conductor on said first deck so that when said
selector switch is in a standby position the annular conductor on
said second deck will be in conductive contact with all of the
fixed contacts in the site positions, and the annular conductor on
said first deck will be out of conductive contact with all of the
fixed contacts in the site positions, and when said selector switch
is in one of the site positions only the fixed contact at the
selected site position on the first check will be in conductive
contact with the annular conductor of the first deck, and all of
the fixed contacts of all of the site positions except the selected
site position on said second deck will be in conductive contact
with said interrupted annular conductor on said second deck.
15. The apparatus set forth in claim 14 together with a plurality
of indicator lights at the monitoring station, there being one
indicator light for each protected station, separate audio
frequency signal responsive means at said monitoring station for
each protected station for energizing the indicator light
associated with a particular protected station when an audio
frequency signal above a preselected threshold level is received
and for deenergizing said indicator light when the audio frequency
signal falls below said threshold level, an audible alarm in
normally open circuit with all of said indicator lights, said
multiposition selector switch having a third deck and means
provided on the third deck only at a standby position for closing
said normally open circuit between said audible alarm and said
indicator lights so that said audible alarm will sound whenever one
of said indicator lights is energized.
16. The apparatus set forth in claim 6 wherein said coupling means
at said monitor station for coupling the audio frequency signals
from each protected station to said multiple position selector
switch is included in a site module, there being plural separate
site modules corresponding in number to the number of protected
stations, each site module having a coupling transformer, an audio
amplifier, and means connecting the output of said audio amplifier
to a particular site position on said multiple position selector
switch, said coupling transformer coupling the audio signals
transmitted over the transmission lines from a particular remote
station to said audio amplifier wherein the audio signals are
amplified.
17. The apparatus set forth in claim 16 together with a plurality
of indicator lights at the monitoring station, there being one
indicator light for each protected station, electric power means
for energizing said indicator lights, and audio signal responsive
means in each site module for energizing the indicator lights
associated with a particular protected station when an audio
frequency signal above a preselected threshold level is received
and for deenergizing said indicator light when the audio frequency
signal falls below said threshold level.
18. The apparatus set forth in claim 17 wherein said audio signal
responsive means includes a threshold level adjusting means
connected to the output of said audio amplifier for picking off a
selected level of the audio output signal, a threshold amplifier
connected to said threshold level adjusting means, a detector means
for detecting the d.c. level of the audio output signal from said
threshold amplifier, a sound operated relay means for opening and
closing the energizing circuit to a particular indicator light, and
means responsive to the d.c. output from said detector means for
energizing said sound operated relay means when the d.c. level is
above a certain level and for deenergizing said sound operated
relay when said d.c. level is below a certain level.
Description
This invention relates to new and useful improvements in electrical
alarm systems of the general type in which a plurality of protected
stations are connected by transmission lines to a central
monitoring station so that abnormal conditions such as burglaries,
fires, hold-ups, or the like, occuring at the protected stations
may be signalled to and detected at the monitoring station.
In conventional systems of this general type the monitoring station
requires separate detecting equipment for each protected station,
thus involving a duplication of components, higher cost, larger
space, and some measure of coordination and dexterity on the part
of the attendant in dealing with the separate detecting equipment
of the several protected stations which are being monitored.
The principal object of the invention is to avoid the above
outlined disadvantages of conventional systems, this being attained
by providing the monitoring station with a master signal detector
which simultaneously monitors all the protected stations, and also
with an individual signal detector and a selector switch so that
when the abnormal condition signal originating at any particular
protected station is detected by the master detector, an
appropriate actuation of the selector switch will transfer that
signal to the individual signal detector where the abnormal
condition at that particular protected station may be individually
monitored, in exclusion of all the other protected stations which
continue to be monitored by the master signal detector.
Thus, undue duplication of components is eliminated in terms of it
not being necessary to provide separate detecting equipment of each
individual protected station. Also, the equipment costs and space
requirements are kept low, and the task of the attendant at the
monitoring station is considerably simplified.
With the foregoing more important objects and features in view and
such other objects and features which may become apparent as this
specification proceeds, the invention will be understood from the
following description taken in conjunction with the accompanying
drawings, wherein like characters of reference are used to
designate like parts, and wherein:
FIG. 1 is a block diagram broadly showing the relationship of
multiple remote protected areas with a central monitoring unit;
FIG. 2 is a front elevational view of the central monitor unit
display panel showing the master detector, individual detector,
selector switch and indicator lights at the central monitoring
station;
FIG. 3 is a partial schematic and partial block diagram of one of
the remote protected stations;
FIG. 4 is a partial schematic and partial block diagram of the
central monitor station;
FIG. 5 is a schematic diagram of the power supply for the central
monitor;
FIG. 6 is a schematic diagram showing the individual lamps
indicating which remote stations are turned-on and the remote
station test switches located at the monitor station;
FIG. 7 is a schematic diagram of the components contained within
each individual site module located at the monitor station; and
FIG. 8 is a schematic diagram of the amplifier circuits for the
individual and master loud speakers. Only one circuit is shown but
two separate similar circuits are required.
Referring now to the accompanying drawings in detail, the
electrical alarm system of the invention comprises a plurality of
remote protected stations which are connected by transmission lines
to a central monitoring station. For illustrative purposes, five of
the remote protected stations, designated generally as 10 in FIG. 1
are connected by transmission lines 12 to a remote monitoring
station 14, it being understood that several, perhaps ten, twenty
or more, protected stations such as the station 10, are connected
to the same monitoring station 14 by additional transmission lines.
For all practical purposes, the transmission lines 12 are leased
telephone lines, so that the use of special lines is not necessary
for purposes of the invention.
In each of the protected stations 10 a condition sensing device is
included which is capable of being monitored and is also capable of
transmitting a signal to the monitoring station 14 when some type
of an abnormal condition comes into being at the protected station,
as for example, a burglary, a fire, a hold-up, or the like.
The monitoring station 14, shown in block diagram in FIG. 1 and
having an instrument panel portion 14a thereof shown in elevation
in FIG. 2, includes a master signal detector 15 which monitors the
condition sensing devices of all of the protected stations 10 at
the same time, and it also includes an individual signal detector
16 and a manually operable selector switch 17, arranged so that
when any particular one of the protected stations 10 sends an
abnormal condition signal which is detected by the master detector
15, that signal may be transferred by an appropriate actuation of
the selector switch 17 to the individual detector 16 in order that
the abnormal condition signal of that particular station may be
monitored individually by the detector 16, in exclusion of all the
other protected stations which continue to be monitored
simultaneously by the master signal detector 15. The instrument
panel portion 14a of the monitoring station 14 also includes a
plurality of indicator lights 18, one for each of the protected
stations 10, and the circuit arrangement at the monitoring station
is such that when an abnormal condition signal is received at the
master signal detector 15 from any one of the protected stations
10, the appropriate indicator lamp 18 of that protected station
becomes energized and thus alerts the attendant of the monitoring
station 14 to the fact that an abnormal condition exists at a
particular protected station. Conveniently, this visual alert may
be accompanied by an audible alert, for example from a buzzer,
which becomes energized with any one of the indicator lamps 18.
In any event, the attendant at the monitoring station 14 then
proceeds to actuate the manual selector switch 17, which has a
plurality of settings corresponding to the respective protected
stations and also to the respective indicator lamps 18, so that
when an abnormal condition signal is received by the master
detector 15 and the protected station sending that signal is
identified by energization of one of the indicator lamps 18, the
attendant turns the selector switch 17 to the appropriate setting
of the protected station as indicated by the corresponding lamp.
This causes the abnormal condition signal from that particular
station to be transferred from the master detector 15 to the
individual detector 16, where that signal may be individually
monitored in exclusion of all the other protected stations which
continue to be monitored simultaneously on the master detector
15.
It may be noted at this point that although the signal transfer
from the master detector 15 to the individual detector 16 is
effected by manual actuation of the selector switch 17 as prompted
by energization of one of the indicator lights 18, the same
operation may be made automatic by utilizing the same signal which
energizes one of the indicator lights 18 to also actuate a suitable
relay circuit by which the selector switch 17 automatically
responds to transfer the signal of a particular protected station
from the master detector 15 to the individual detector 16.
Referring now to FIG. 3 each protected remote station 10 such as a
home, store, office, school, etc. which is being monitored includes
one or more microphone sound pickups 20 located within the remote
station for detecting sound produced within the range of the
microphones. Sound picked up by the microphones is amplified in an
amplifier 21 which may include one or more audio amplifier stages
of conventional type. The audio output from the amplifier 21 is
coupled by means of a coupling transformer 37 and a Y-pad 38 to a
pair of leased telephone lines 12 extending between the remote
station and the monitor station subsequently to be described. The
amplifier 21 is powered from an AC to DC power supply 28 of a
conventional type which receives AC current from a 117 volt AC
source through a fuse F1 in one leg and through one section 30a of
a double pole activate switch 30. When the activate switch 30 is
closed, the power supply 28 is energized and converts AC to DC for
supply of the amplifier 21 and various devices to be described.
For the purpose of testing the operative condition of the remote
station from the monitor station 14 an audio noise generator 40,
which will also be referred to as a Sonalert, is connected in
circuit with the power supply 28 and a relay switch 39a. The
energizing coil 39 of the relay switch is connected on one side to
a second section 30b of the activate switch 30 and from there to
ground, and the other side is connected through a center tap 37c on
the secondary side 37b of coupling transformer 37, the conductors
41, telephone lines 12 to line transformer 22 at the monitor
station 14 (See FIG. 4) from whence it is connected by means of a
center tap on the primary side of the line transformer 22 through a
normally open test switch (See FIG. 6) to a 91 volt DC bus at the
monitor station 14. When it is desired to test the operativeness of
the microphones 20 and amplifier 21 at a remote station the
operator at the monitor station 14 actuates the test switch
associated with the selected remote station which energizes the
relay coil 39 and closes the circuit to the Sonalert device 40. The
Sonalert device 40 produces an audible sound which is picked up by
the microphones 20, amplified and transmitted from the remote
station 10 over the leased lines 12 to the monitor station 14 where
the sound is monitored in a manner subsequently to be
described.
Also present at the remote station may be various auxiliary devices
including an emergency alarm overide switch 29, and several means
for detecting and signalling various abnormal conditions such as
fire, temperature, burglary etc. The emergency alarm overide switch
29 is provided so that someone at the remote station may signal to
the monitor station 14 merely by depressing the emergency alarm
overide switch 29. The switch 29 is in circuit with a 6 volt
battery source 28' which energizes an oscillator 32 to produce a
three thousand Hertz signal which is coupled through a coupling
transformer 42, the Y-pad 38 and the telephone lines 12 to the
monitor station 14.
Connected in parallel circuit with the normally open switch 29 are
a plurality of diverse condition sensing and encoding circuits. A
fire condition sensing circuit includes the fire sensing switch 33a
and a fire alarm encoder 33 driven by a 12 rpm DC motor 33b. The
encoder 33 is a rotary switch having an annular rotary conductor
ring 33' which is continuously wiped by a brush contact 33"
connected to one side of the sensing switch 33a. An arcuate
conductor segment projecting radially from the conductor ring 33'
successively engages the fixed contacts which are equally spaced in
an annular ring about the annular conductor 33'. The arcuate
segment 33c is long enough so that it will bridge a pair of
adjacent fixed contacts 33d simultaneously so that the segment 33c
will always be in contact with one of the fixed contacts 33d as it
rotates through 360.degree.. By contacting various of the fixed
contacts to the other side of the circuit from the sensing switch
34a and leaving other of the fixed contacts vacant, it will be
apparent that different code patterns may be established based on
successive pulse code patterns wherein the pulses are of various
widths and are variously spaced. The encoder 33 is connected to
produce a dash-dash code of equally spaced pulses of equal
prolonged pulse width.
The other encoders 34 and 35 are similar to the encoder 33 except
that they are connected to produce a different pulse pattern. They
each have a condition sensing switch 34a and 35a associated with
the encoders 34 and 35 respectively. The encoder 34, which is
designated a temperature alarm encoder is connected to produce a
code of successive dot-dash-dot-dash pulses. The encoder 35 which
is designated "other" is connected to produce dash-dot-dash pulse
sequences. The sensing switches 33a, 34a and 35a are selected
according to the condition which they are intended to sense and may
be of various types well known in the art. The fire and temperature
sensing switches may be thermostats of various temperature settings
adapted to close circuits when temperatures are too high, or if the
temperature has too rapid a rate of rise. Any number of condition
sensing circuits may be included as desired. The condition sensing
switch 36 which may be closed in response to the misplacement of an
object during a burglary attempt will produce a continuous signal
when closed.
The condition sensing switches and their respective encoders being
parallel connected in the energizing circuit of the 3KHZ oscillator
effectively key the oscillator when activated in response to an
abnormal condition so that the oscillator produces a pulse coded
output of audible frequency. The 6 volt battery 28' is common to
all of the encoders. The relays 43, 44 and 45 having their
energizing coils connected in parallel with the encoder drive
motors 33b, 34b and 35b respectively and having their movable
contacts 43a, 44a and 45a connected in circuit between the encoders
33, 34 and 35 respectively and the oscillator 32 are provided so
that the alarms will not sound if the encoder motors stop on a
contact position. The relays 43, 44 and 45 will normally open their
respective encoder circuits when the associated motors 33b, 34b and
35b are de-energized, but will close their respective encoder
circuits when the associated motors are energized.
Turning now to the monitor station as shown in FIG. 4 it will be
seen that transmission lines 12 from each protected station 10
connect with an individual site module 47 of which there are
several identical modules corresponding in number with the number
of protected remote stations 10. Since the site modules 47 are
identical, only one will be described. The site modules each
include a line transformer 22, an audio line amplifier 23, and a
threshold amplifier and relay switch package 24. Audio frequency
signals transmitted from the protected station over the
transmission lines 12 are coupled through the line transformer 22
to the audio amplifier 23 which amplifies the audio frequency
signal. The line amplifier 23 may include one or more audio stages
as needed. Parallel outputs from the line amplifier are taken off
by means of adjustable potentiometers 48 and 49. The potentiometer
48 is a volume control potentiometer and the audio signal taken
therefrom is fed simultaneously to fixed contacts on the first and
second decks of the three deck rotary selector switch 17. The audio
signal from a particularly numbered site module is fed to
correspondingly numbered fixed contacts on the first and second
decks of the switch 17. That is, the audio output from site module
#5 is fed to the fixed contacts #5 on the first and second switch
decks, the audio output from site module #4 is fed to the #4 fixed
contacts on the first and second switch decks, and in like manner
the audio outputs from the other side modules #3, #2 and #1 are fed
to fixed contacts #3, #2 and #1 on the first and second switch
decks respectively.
The switch deck #1 includes an annular conductor ring 50 having an
arcuate lateral projection which engages the fixed contacts 1-10 on
the switch deck in sequence. A brush 52 contacts the conductor ring
50 at all times and transmits any signal picked off by the arcuate
segment 51 from a particular numbered fixed contact to an amplifier
27 which feeds the signal to the individual loud speaker 16. It
will therefore be seen by examination of the switch deck #1 that
only the audio signal from one site module and thus from one
protected station can be fed to the individual speaker 16 in any
one position of the selector switch 17 thus the operator at the
monitor station 14 is able to monitor the sound and audio alarm
signals derived from a selected remote station.
The switch deck #2 includes an arcuate rotary conductor segment 54
which lacks being a complete circle by a short gap 55 of length
less than the distance between adjacent fixed contacts which are
uniformly spaced circularly about the outside of the conductor
segment. The fixed contacts 1-10 are all provided with means for
wiping the arcuate segment 54. A brush 56 connected with the
amplifier 26 is also in contact with the rotary conductor segment
54 and will transmit any signal being picked up by the rotary
segment 54 from the fixed contacts 2-10 wiping the segment 54 to
the amplifier 26. The amplifier 26 amplifies the audio alarm
signals present and drives the master loud speaker 15 with the
amplified audio signals. Since the conductor segment 54 is in
contact with all of the fixed contacts 1-10 except the one where
the gap 55 occurs it will be seen that all signals from the site
modules 47 connected to the switch deck #2 will be sampled
simultaneously except for the signals from the site module 47
connected to fixed contact adjacent gap 55. In the position of the
selector switch 17 shown the gap 55 is adjacent contact 1, thus the
signal from site module #1 is not being picked up by the master
speaker 15. However, turning now to switch deck #1 it will be
observed that any signals from site module #1 are being transmitted
from contact 1 through the arcuate segment 51 conductor ring 50,
and brush 52 to the amplifier 27 from which the audio signals are
applied to the individual speaker 16.
The switch deck #3 of the selector switch 17 is provided so that an
energizing circuit through an audible buzzer 65 may be put in a
ready condition by switching the selector switch 17 to a standby
position which is just to the right, or counterclockwise from the
fixed contact #1. The deck #3 includes an annular rotary conductor
57 which has a lateral arcuate projection 58 and multiple fixed
contacts equally spaced in a circle about the rotary conductor 57.
The fixed contacts numbered 1-10 are vacant and thus have no
electrical function in the system. The two contacts a and b to the
right of the fixed contact #1 have conducting means for engaging
the arcuate segment 58; they also are electrically tied together by
a conductor 60 and are connected to one side of a buzzer 65, a
capacitor 66 and a resistor 67 which are parallel connected between
conductor 60 and ground. A brush 59 which engages the rotary
conductor 57 is connected to the fixed contact c just clockwise of
the numbered contact 10. When the selector switch 17 is turned
counterclockwise off of the fixed contact 1 it is placed in a
standby position wherein the arcuate segment 58 is in electrical
contact with the fixed contact a and an electrical circuit is
completed from ground through the buzzer 65 fixed contact a,
segment 58, conductor ring 57, brush 59, diode D1 to the bottom
side of parallel alarm indicator lamps 18 whose function will be
subsequently described. Looking to switch decks #1 and #2, when the
selector switch 17 is moved to the standby position arcuate segment
51 is moved counterclockwise off contact 1 so that none of the site
modules 47 will be connected through deck #1 to the individual
speaker 16. The gap 55 in rotary conductor 54 will be moved from
position over contact 1 to a position over contact a and the
conductor segment 54 will contact all of the fixed contacts to
which the site modules 1-5 are connected. Thus in the standby
position all of the protected areas 10 will be monitored by the
master speaker 15 through switch deck #2 while none of the
protected areas 10 will be monitored by the individual speaker 16.
If the selector switch 17 is moved one more position
counterclockwise so that segment 58 on deck #3 engages contact b
the circuit from the bottom of lamps 18 through buzzer 65 to ground
will still be closed. However since the brush 56 on deck #2 is
connected to contact b and the gap 55 will now overlie the brush 56
none of the protected areas 10 can be monitored by the master
speaker. In deck #1 the segment 51 will be over contact b to which
brush 52 is connected but none of the site modules will be
connected to the conductor ring 50 and therefore no signals from
any of the protected areas will be monitored by the individual
speaker.
Referring back to the site module #5 it will be seen that a portion
of the audio output signal from amplifier 23 is tapped off by the
sensitivity adjust potentiometer 49 and is fed into a threshold
amplifier and relay switch package 24. This package 24 which will
be discussed in greater detail with reference to FIG. 7 controls
the sound operated relay switch 68 so that the switch 68 closes
when the audio level of signals from the amplifier 23 exceeds a
predetermined threshold level determined by the position of the
adjustable sensitivity potentiometer 49. As seen in FIG. 4 each of
the site modules includes a sound operated relay switch 68. One
side of each relay switch 68 is connected to a 6.3 volt AC bus
supplied from a grounded 6.3 volt AC power supply seen in FIG.
5.
The other side of each relay switch 68 is separately connected in
series with one of the multiple parallel connected indicator lamps
18, and diode D2 to ground. Thus when one of the sound operated
relay switches 68 is closed in response to a signal received from a
protected station 10 one of the indicator lights 18 will be
energized. Each of the indicator lights are numbered to correspond
to the number assigned to the protected station with which it is
associated so that an operator at the central monitor station can
determine from the lighted indicator lamp which protected station
is sending an alarm signal. The circuits for the indicator lamps 18
do not go through the selector switch 17 so the indicator lamp will
signal upon actuation of an associated sound operated relay switch
irrespective of the position of the selector switch.
The audible buzzer 65 is intended to give an audible alarm signal
to the operator at the central station only when the selector
switch 17 is in a standby position and any one of the sound
operated relays closes in response to an alarm signal from a
protected station. The operator being advised that an alarm
condition exists by means of the audible sound from buzzer 65 can
determine from observation of the visual alarm lamps 18 which
station is sending the alarm. The operator will then switch the
selector switch 17 to a position corresponding to the protected
station sending the alarm. The operator then will be able to
monitor the sound originating at the station to which the selector
switch is set by means of the individual speaker 16, and can also
monitor sound originating at all other protected stations by means
of the master speaker 15.
The power supply for the central monitor is shown in FIG. 5 and
includes a regulated 12 volt DC supply 70, a 6.3 volt AC supply 71
and a regulated 91 volt DC supply 72. These supplies are of
conventional construction and need not be further described in
detail except to say that the power supplies are energized from a
117 volt AC source 73 through appropriate sections of a transformer
74. The 12 volt DC supply rated at 625 ma provides power for all
site modules 47 and the amplifiers 26 and 27; the 6.3 volt AC
supply rated at 2 amperes provides power to energize the visual
indicator lamps 18; and the 91 volt DC supply rated at 40 ma
provides power for the neon lamps 31 and for activating the relays
39 in the remote stations 10.
The circuits shown in FIG. 6 are provided so that an operator at
the monitor station 14 can observe and test the operative condition
of the equipment at the protected stations 10 and the continuity of
transmission lines 12. Neon lamps 31 (there being one for each
protected station numbered in accord with the number of the
protected stations with which a particular lamp is associated) are
mounted on the instrument panel 14a (see FIG. 2) within view of the
operator at the monitor station. Beside each neon lamp 31 is a push
button test switch 46 also associated with a particular protected
station. The parallel neon lamps 31 each with an associated voltage
dropping resistor 76 in series with the power supply 72 and with a
shunting resistor 75 are connected through separate conductors
shown broken away at X1, X2, X3, X4 and X5 respectively to
similarly marked conductors shown in FIG. 4 and to the center taps
22' on the primary windings of the line transformers 22 in
particular site modules with which the individual lamps are
associated. The neon lamp circuits are completed through associated
transmission lines 12, conductors 41, transformer primary 37b,
relay coil 39 and activate switch section 30b in the remote station
10. When the activate switch 30 is closed in a particular remote
station 10 and the circuits between the indicator lamps 31 and the
activate switch 30 are continuous the lamp 31 associated with the
particular remote station 10 will light indicating the integrity of
the circuits and that the set in the protected station 10 is
activated. The current flowing through the neon lamps 31 and
resistors 75 and 76 will normally be insufficient to energize the
relay 39 in the remote station. The parallel test switches 46 in
series with resistor 77 and the 91 volt DC power supply 72 are
connected to parallel the indicator lamps 31 and resistors 75 and
76. Depression of any of the test switches 47 will provide
sufficient current through an associated relay 39 in a particular
remote station to energize the relay and close relay switch 39a so
that the circuits between power supply 28 and the audible noise
generator 40 in the remote station is completed. The noise
generator 40 will then sound and the noise will be picked up by
microphones 20 and transmitted as an alarm test signal to the
monitor station. If the test signal is received at the monitor
station 14 in the normal manner the operator at the monitor station
will be assured that the equipment at the remote station and at the
monitor station associated with the particular remote station being
tested is in operative condition. If the test signal is not
received at the monitor station in the normal manner the operator
will know that equipment associated with the particular remote
station being tested is impaired and can take appropriate
corrective action.
A detailed schematic of typical circuitry within a site module 47
is shown in FIG. 7. The basic components of a site module are
indicated in the site module #5 shown in FIG. 4 as being a line
transformer 22, an audio line amplifier 23, a threshold amplifier
and relay switch package 24 and the sound operated relay switch 68.
Each of these components are individually of substantially
conventional design and various circuits capable of performing the
same function as has been described for the basic components may be
substituted within the scope of this invention. Thus while the
circuits of a typical site module are shown in FIG. 7 this
invention is not limited to the details of the circuits shown in
FIG. 7.
Since each site module 47 is a self contained unit which can be
readily interchanged with identical units in the event of
malfunction, FIG. 7 shows all connecting terminals for the unit on
the left hand side. It will be understood that these terminals are
associated with a suitable connector so that the site module unit
may be quickly connected and disconnected as need arises. The
transmission lines 12 from a remote station are connected to the
input terminals 3 and 5 and these terminals are connected
internally to opposite sides of the primary winding of line
transformer 22. Terminal 2 is connected to the 91 volt DC supply 72
in the power supply unit shown in FIG. 5. Audio signals coupled
through the line transformer are fed to the audio line transformer
23 which includes a transistor amplifier Q1 of the type 2N1305
operating Class A. Output signals from the emitter of transistor Q1
are taken off from adjustable gain and sensitivity potentiometers
48 and 49 connected in parallel. The audio output from gain
potentiometer 48 is fed through a coupling capacitor 78 to the base
of a second stage amplifier Q2 also of type 2N1305 and operating in
Class A. The second stage amplifier Q2 further amplifies the audio
signal taken from the gain potentiometer and feeds the audio output
through coupling capacitor 79 to output terminal 1 from which it is
fed by suitable conductor means to the numbered fixed contacts on
the decks #1 and #2 of the selector switch 17 corresponding to a
particular numbered site module. The output from the sensitivity
adjust potentiometer is fed through a coupling capacitor to the
threshold amplifier Q3 in the threshold amplifier, relay switch
package generally indicated by the arrow 24. The amplifier Q3 is a
transistor amplifier type 2N3638 operating Class A for further
amplifying the audio signal taken from the sensitivity
potentiometer 49. The output from amplifier Q3 is coupled through
capacitor 81 to the transistor detector Q4 which produces a DC
output corresponding to the voltage level of the audio signal. The
output from detector Q4 is used to trigger the transistor switch Q5
which is in series circuit with the relay coil 68' of the sound
operated relay switch 68. When the transistor switch Q5 is
triggered on by an audio signal of a selected threshold level
current flowing through the transistor Q5 will also flow through
the relay coil 68' causing the relay switch 68 to close. One side
of the relay switch 68 is connected to the 6.3 volt AC bus through
terminal #6. And the other side of switch 68 is connected to an
indicator light 18 through terminal 7. As previously explained the
closing of relay switch 68 will cause the indicator light 18
associated with a particular site module to light. The sensitivity,
or audible threshold level of the sound operated relay 68 is
adjusted by means of the sensitivity potentiometer 49. Sounds
picked up by the microphones 20 in the protected area 10 which are
below a predetermined threshold level will not cause the sound
operated relay 68 to operate. However sounds above the
predetermined threshold level will trigger the transistor switch Q5
and close the sound operated relay switch 68 thus providing an
alarm signal through a visual indicator lamp 18 and if the central
monitor is in standby condition will cause the audible buzzer alarm
65 to sound.
The terminals 8 and 9 of the site module are connected to the 12
volt DC bus in the power supply and to ground respectively.
Normally the threshold amplifier sensitivity potentiometer 49 will
be adjusted so that a minimum signal of -20 d.b. is required to
close the relay switch 68. Transistors Q4 and Q5 are of type
2N3638.
FIG. 8 shows typical circuitry suitable for the individual speaker
16 and speaker amplifier 27 as well as for the master speaker 15
and master speaker amplifier 26. This circuitry is of conventional
design whose function will be obvious to one with ordinary skill in
the art for which reason a detailed description thereon will be
omitted. However, depending on whether the circuit is used in
conjunction with the individual speaker or the master speaker, both
using similar circuitry, audio signals from the selector switch are
fed through a volume control potentiometer 90 and coupling
capacitor 91 to an audio amplifier module 92. The output from
amplifier module 92 is fed to the primary 93 of transformer T1.
Balanced outputs are taken from the secondary transformer coils 94
and 95 and fed as inputs to the loudspeaker driver amplifiers Q6
and Q7. The driver amplifiers Q6 and Q7 are type 2N2869 transistors
which are connected to drive a loudspeaker which may be either the
individual speaker 16 or the master speaker 15 as the case may
be.
The operation of my alarm system which it is believed will be
understood from the foregoing description will be briefly
summarized.
A central monitor station 14 is connected to plural remote
protected stations 10 by transmission lines 12 and is adapted to
receive audio frequency signals from the protected stations. The
audio signals may merely be derived from sound pickup microphones
20 within the protected stations 10 or may be obtained from
abnormal condition sensing devices and encoders such as the fire,
temperature, other, and burglary encoders 33,34, 35 and 36 shown in
FIG. 3. The abnormal condition sensing devices which are energized
from the 6 volt battery 28' are emergency items which are intended
to be operative at all times especially when the activate switch 38
is open and the sound pickup system is off. Each remote station 10
must close an activate switch 30 in order to put the premises under
the sound surveilance of the central monitor station. Normally the
activate switch will be closed at times when normal use and
occupation of the building is not anticipated such as in the case
of an office at the close of a business day. Closing the activate
switch 30 energizes the audio amplifier 21 and pickup microphones
20.
In the central monitor station an attendant will normally be on
duty in the vicinity of the instrument panel 14a shown in FIG. 2.
The attendant will usually keep the selector switch 17 in a standby
position as indicated in FIG. 2, where the rotary dial knob 63 is
turned so that the pointer 64 is in one of two positions, a or b,
counterclockwise of the first site position 1. In the standby
position a the attendant at the monitor station can listen through
the master speaker to sounds being derived from all of the
protected premises wherein the activate switch 30 has been closed.
When sound above a predetermined threshold level is derived from a
protected station 10 the sound operated relay 68 within the site
module associated with the protected station sending the audio
signal will close and the visual alarm indicator light 18
associated with the particular protected station will light to
indicate which station is sending the alarm. Also the buzzer 65
(see FIG. 4) will sound to further attract the operator's
attention. The operator may then turn the selector switch indicator
dial 63 so that the pointer 64 points to the number of the station
from which the alarm signal is being sent. The individual speaker
16 will then be connected through deck 1 of the selector switch 17
to the output of an audio amplifier 23 in the site module of the
selected station and audio signals coming from the selected station
will be monitored by the individual speaker 16 to the exclusion of
all other stations. However, any sounds from the other stations
will be monitored by the master speaker 15 simultaneously through
switch deck #2 of the selector switch. The buzzer 65 will be turned
off as soon as the selector switch 17 is turned to point to a
particular site number, but the visual indicator lamps 18 will be
in ready condition at all times irrespective of the position of the
selector switch 17. The attendant at the monitor station can adjust
the volume of sound from the speakers 15 and 16 by means of volume
control knobs 100 and 101 respectively on the instrument panel 14a.
These knobs control the gain potentiometer 90 of identical audio
amplifiers 26 and 27 respectively as shown in FIG. 8.
The attendant can also observe which remote stations are activated
by means of the lamps 31 which will be energized as soon as the
activate switch 30 in protected stations are closed. A lighted lamp
31 means that a station 10 associated with the lamp is activated.
If a lamp 31 is not lighted the associated remote station is either
not activated or there is a malfunction. The attendant can test the
sound monitoring system of a particular station 10 by depressing an
associated test switch 46 which will energize a noise generator in
an activated remote station which sound will be picked up in the
remote station by microphone 20 and transmitted to the monitor
station 14 provided the audio monitoring system is functioning
properly. If no sound is received the attendant knows that a
malfunction associated with the particular station being tested
exists.
The reason for providing the condition encoders 34, 35 and 36 with
different code patterns is so that the monitoring attendant can
identify the particular abnormal condition being detected and take
appropriate action.
It is preferred that the audible noise generator 40 described in
reference to FIG. 1 and the audible buzzer 65 described in
reference to FIG. 4 be an electronic audible signal generator of
the type manufactured and sold under the trademark SONALERT by P.
R. Mallary and Co., Inc. and described in the two page
specification Form 9-398A entitled "Sonalert." While other noise
generators may be used the Sonalert device is especially suitable
for use with this invention because its circuitry is all solid
state with the consequent low current requirements. With reference
to FIG. 4, the 6.3 volt AC through lamps 18 is fed to the
rectifiers D1 and D2 and is filtered by condenser 66. The resistor
67 determines the amount of voltage to be rectified for the
Sonalert 65 from the 6.3 volt AC applied to the indicator lights
18. The current consumption of the Sonalert will be very low.
Again with reference to FIG. 6 the resistors 75 and 76 associated
with the neon lamps 31 are provided to simulate transmission line
leakage of a minor nature. Otherwise the neon lamps 31 would fire
with most any high resistance line leakage to ground. The neon lamp
circuits use the ground path to return.
It should be recognized that while for convenience and simplicity
in illustrating the invention only five remote protected stations
have been shown and a selector switch with only ten site positions
has been shown; it will be understood that the system is not
limited to a specific number of remote protected stations as long
as a selector switch with sufficient positions to handle the
desired number of remote stations can be obtained.
While in the foregoing there has been described and shown the
preferred embodiment of the invention, various modifications and
equivalents may be resorted to within the spirit and scope of the
invention as claimed.
* * * * *