U.S. patent number 3,710,313 [Application Number 05/106,170] was granted by the patent office on 1973-01-09 for emergency warning systems.
Invention is credited to Robert H. Hagey, Pleasent P. Kimball, Malcolm J. Macaulay.
United States Patent |
3,710,313 |
Kimball , et al. |
January 9, 1973 |
EMERGENCY WARNING SYSTEMS
Abstract
Communications warning apparatus of the type wherein a
transmitter is mounted in an emergency vehicle and one or more
frequency-adaptive receivers are mounted in other vehicles. This
system utilizes an FM transmitter coupled with recorder and play
back mechanism in the emergency vehicle so that transmission can be
effected in any of three modes, i.e. modulated C-W, voice
transmission or repetitive recorded voice message, and transmission
is effected at such frequency that all surrounding vehicles having
a required receiver instrument will receive such warning or message
preferentially over a receiver instrument or modular adapter
utilized with a standard car radio.
Inventors: |
Kimball; Pleasent P. (San
Francisco, CA), Hagey; Robert H. (Oklahoma City, OK),
Macaulay; Malcolm J. (Oklahoma City, OK) |
Family
ID: |
22309887 |
Appl.
No.: |
05/106,170 |
Filed: |
January 13, 1971 |
Current U.S.
Class: |
340/902; 369/19;
455/527; 340/904; 455/1 |
Current CPC
Class: |
G08G
1/094 (20130101); G08B 25/016 (20130101); G08G
1/0965 (20130101) |
Current International
Class: |
G08G
1/0962 (20060101); G08G 1/09 (20060101); G08G
1/0965 (20060101); G08B 25/01 (20060101); G08g
001/00 () |
Field of
Search: |
;340/33,34 ;179/1VE,1.1C
;325/64 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Caldwell; John W.
Assistant Examiner: Mooney; Robert J.
Claims
What is claimed is:
1. An electronic warning system for use in apprising one or more
vehicle operators of information relating to or emanating from an
emergency vehicle, comprising:
frequency modulated transmitter means including a directional
antenna mounted on said emergency vehicle to propagate radio
frequency energy essentially forward of said emergency vehicle;
modulator means disposed in said emergency vehicle to modulate the
transmitted output of said frequency modulated transmitter
means;
mode selector means consisting of plural position switch means
having first, second and third inputs and first and second outputs
connected to select one of plural inputs of audio frequency signal
for conduction via either a first output to said modulator means or
a second output;
microphone means providing a first audio signal input to said mode
selector means first input;
tone generator means generating a constant frequency second audio
frequency signal for input to said second input of said mode
selector means;
record-playback means connected to said mode selector means second
output and being actuatable to receive voice input from said
microphone means for recording on an endless record of pre-set
length, said recorder-playback means being actuable to playback
said recorded message to provide a third audio frequency signal
output to said third input of the mode selector means; and
one or more receiver means disposed at one or more vehicle
positions to receive said frequency modulated radio frequency
energy to provide an output in the form of a visible and/or audible
warning to said vehicle operator.
2. An electronic warning system as set forth in claim 1 which is
further characterized to include:
time indicating means actuated to commence time count upon
actuation of said record-playback means for recording.
3. An electronic warning system as set forth in claim 2 which is
further characterized in that:
said time indicating means total count duration is synchronized
with one revolution of said record-playback means endless
record.
4. An electronic warning system as set forth in claim 1 wherein
said record-playback means comprises:
a loop of magnetic recording tape;
tape transport means receiving said tape loop;
drive means providing drive output to said tape transport
means;
transducing means affixed in operative position engaging said tape
loop; and
control means controlling said transducing means for record or
playback of audio frequency signal.
5. An electronic warning system as set forth in claim 4 which is
further characterized to include:
time indicating means actuated to commence time count upon
actuation of said record-playback means for recording.
6. An electronic warning system as set forth in claim 1 wherein
said receiver means each include:
test oscillator means actuatable to produce an alternating
electrical signal output; and
inductive means coupling said alternating electrical signal output
to said respective receiver means.
7. An electronic warning system as set forth in claim 4 wherein
said plural position switch means comprises:
switch means for selectively connecting said microphone means first
audio signal to said modulator means, or said microphone means
first audio signal to said record-playback means, or said tone
generator means second audio signal to said modulator means, or
said record-playback means third audio signal to said modulator
means.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to emergency vehicle warning
systems and, more particularly, but not by way of limitation, it
relates to improvements in radio frequency transmission systems as
used for intercommunication between motor vehicles and the
like.
2. Description of the Prior Art
The Prior Art includes various types of radio energy transmission
systems of the general type which serve to effect a selective
transmission from an emergency vehicle, i.e. ambulance, fire truck,
police car, etc., for the purpose of generating a warning
transmission for reception by various other vehicles which may be
in the immediate path of the emergency vehicle. Receivers of the
forerunner systems have been adapted to provide such as a warning
buzzer or dash-light indication to normal traffic drivers in their
vehicles an response to such emergency vehicle transmission, and
some receiver instruments have been adapted to exercise
preferential transmission selection or override reception of
emergency warning information on the standard vehicle receiver.
Systems have also been designed wherein transmission from an
emergency vehicle or the like can provide output energy at a
preselected frequency for the purpose of effecting charge of
on-coming traffic lights to green along the route of travel. These
systems too are primarily a modulated FM frequency transmitter
propagating a characteristic frequency adapted or selected for
reception and operational control by a suitable device associated
with the traffic light switching system.
SUMMARY OF THE INVENTION
The present invention contemplates an emergency warning
transmission system wherein the emergency vehicle transmitter
instrument is capable of plural mode transmission operation to
enable selection of one of several types of warning transmission.
In a more limited aspect, the invention consists of a transmitter
assembly in the emergency vehicle which includes an associated
record-playback apparatus which enables the emergency vehicle
operator to transmit at any of several modes, i.e. modulated C-W
transmission, direct voice transmission, automatic repetitive voice
warning as effected by the play back instrument. One or more
vehicles, preferably all surrounding vehicles, are then outfitted
with receiver instruments which are sensitive to the characteristic
frequency transmission to pick up such emergency transmissions for
reproduction to the driver of the vehicle or vehicles in the
immediate vicinity to audibly reproduce a suitable warning message
as to approach of an emergency vehicle, accident ahead, icy bridge
condition, etc.
Therefore, it is an object of the present invention to provide an
emergency warning system having greater capability through
increasing the number of modes of operation to satisfy requirements
of all exigencies.
It is also an object of the invention to provide emergency warning
apparatus which will provide emergency warning to all vehicles in
the vicinity despite tightly sound-proofed autos, air conditioner
noise within individual autos, and other hindrances to the
audibility of siren-type warnings as presently employed.
It is yet another object of the invention to provide a warning
system which is cable of delivering a voice message in repetitive
form automatically without requiring constant attention from the
operator of an emergency vehicle.
Finally, it is an object of the present invention to provide an
emergency warning system of the type utilized in radio energy
transmission which is of very low cost and high reliability and
which enables plural operating modes for maximum effect warning
operation as between an emergency vehicle or warning station and
the general or normal flow of vehicle traffic.
Other objects and advantages of the invention will be evident from
the following detailed description when read in conjunction with
the accompanying drawings which illustrate the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a radio transmitter as employed in the
system of the invention;
FIG. 2 is a suitable form of front panel layout of one form of
vehicle-mounted transmitter instrument as may be employed in the
invention;
FIG. 3 is a block diagram of the recorder portion of the FIG. 1
transmitter circuitry;
FIG. 4 is a block diagram of a suitable form of receiver instrument
for use in the present invention;
FIG. 5 is an elevation view of a suitable form of front panel lay
out as might be employed with a receiver instrument;
FIG. 6 is a plan view illustrating an alternative usage of the
present invention; and
FIG. 7 is a block diagram of an alternative form of receiver
structure.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, the transmitter 10 includes such as a
signal input circuitry 12 providing input to a modulator 14. The
modular 14 is then connected in conventional manner to apply
modulating signal to an FM transmitter 16 which, in turn, provides
output to an antenna 18 for propagation of the radio frequency
energy. The FM transmitter 16 may be such as a standard solid state
FM transmitter of the continuous wave type and including design
allowances for the specific amplification functions. It is
contemplated that production considerations will result in the use
of modularized or encapsulated circuits.
Transmitter 16 should transmit energy at a frequency as assigned or
selected by the FCC. Propagation from antenna 18 should be
concentrated in the forward direction. It is probably sufficient
that the transmitter operate with an input of between 1 and 25
watts average power so as to limit the range of reception of the
transmitter to approximately 1 mile. Further, the frequency of
transmission should be high enough to be directional so that the
energy can be transmitted from the front of the emergency vehicle,
by means of a suitable form of antenna instrument (not specifically
shown) and yet the frequency should be low enough to eliminate line
of sight limitations such that adequate coverage is assured for
downtown business or high building areas.
The antenna 18 should be designed to propagate the radio energy in
a major lobe approximately 120.degree. between half power points
and directed forwardly of the emergency vehicle. Minor side lobes
and other lobing effects may be sufficiently minimized utilizing
well-known antenna design considerations that should not
necessitate expensive fixtures. The antenna 18 may be permanently
affixed atop or on the front of an emergency vehicle or emergency
warning station along a highway since the antenna is highly
specialized in form and function.
The input circuitry 12 includes a microphone 20 connected to
provide voice input upon depression of key 21 via connector cable
22 to a mode selector 24. The mode selector 24 may be such as a
ganged, plural contact switch, e.g. a plural circuit rotary wafer
switch, for receiving input signals relative to various modes of
operation. A tone generator 26 serves to generate a suitable
constant frequency tone for modulated C-W operation. Tone generator
26 provides such as a 1,000 cycle tone as output via lead 28 for
application to mode selector 24.
A recorder 30 may be a conventional form of record-playback
instrument as connected via leads 32 and 34 to mode selector 24 to
provide yet another mode of operation, as will be further described
below. Thus, mode selector 24 may select any of (a) voice
communication as input at microphone 20, (b) C-W tone modulation as
generated by tone generator 26 or (c) a selected recorded message
as recorded on recorder 30 for selected playback and
transmission.
FIG. 2 illustrates the front panel of one form of instrument which
may be mounted in the emergency vehicle. Thus, a transmitter
instrument 36 may include a front panel 38 with connections being
made at side-mounted receptables. Supply voltage from the system
battery or the like may be applied via lead 40 through the ignition
system 42 and lead 44 to an input jack 46, and voice input from
microphone 20 is effected through a cable 48 and input jack 50.
Front panel 38 may include a loudspeaker grille 52 and an indicator
dial light 54 to denote equipment ON condition. A screwdriver
adjust 56 may be included to enable permanent setting of modulation
and volume levels. A two position switch 58, e.g. a conventional
toggle-type switch, may be utilized to provide ON-OFF control or
application of the supply voltage.
A mode selector switch 60, here shown in the modulated C-W or alert
position 62, may be operated to any of additional positions 64, 66
and 68 to select voice transmission, tape message transmission and
tape message record mode, respectively. Thus, tape record position
68 enables the operator of the emergency vehicle to speak a message
through microphone 20 for recording on the recorder 30 (as will be
further described below), whereupon placement of the mode switch 60
to tape transmit position 66 will then enable repetitive play back
and transmission of the taped message. A time meter 69 enables the
operator to observe elapsed record time visually during recording
so that the message is better fitted into available time. It is
probably preferrable that time meter 69 only be energized during
the Tape Record position 68 of mode switch 60.
FIG. 3 illustrates the mode selector 24 and recorder 30 in greater
detail. Thus, a suitable form of record-playback mechanism 70 is
utilized to provide recording capability, e.g. 20 to 30 seconds of
record time. While record-playback mechanism 70 may be any of
various commercially available units, considerations of cost,
reliability and preferable function have prompted the selected of
an endless record type of record-playback apparatus. Thus, an
endless record, e.g. a tape or wire record, is driven around a
drive pulley 74 and an idler pulley 76 across a transducing
position 78 wherein recording and playback are effected. Drive
pulley 74 is driven by means of a drive control 80 as indicated by
dash-line linkage 82. Drive control 80 is controlled via electrical
connection 84 from mode selector switch 24.
Input audio information from mode selector 24 is applied via lead
86 through a suitable form of input amplifier 88 and lead 90 to a
recording head 92. Recording head 92 then engages endless tape 72
at the transducing position 78 to effect recording of the input
audio message. Playback from endless tape 72 may be effected by a
transducer 94 with signal output on a lead 96 for input to an audio
amplifier 98 whereupon amplified audio energy is available on lead
34 for input to mode selector 24. A head selector 100, e.g. a
suitable solenoid control, receives energization via lead 102 from
mode selector 24 to engage one or the other of the record head 92
or play back 94, as indicated generally by the connecting linkage
104. While the record-playback transducing heads 92 and 94 are
indicated as separate implements, it should be understood that
there are many choices regarding this structure and it may be most
desirable to employ a combined-type of head which effects both
playback and reproduction without the necessity for physical
movement. In addition it should also be understood that the record
head 92 containing suitable erase windings supplied by an erase
bias amplifier to effect erasure of any previously recorded message
on the tape immediately before recording a new message.
A receiver 110 suitable for use in the emergency warning system is
illustrated in FIG. 4. Incoming radio energy received by an antenna
112 is applied to an FM receiver 114. FM receiver 114 may be such
as an FM crystal-controlled receiver of solid state design which is
tuned to receive the frequency or frequencies at which the system
transmitter in one or more emergency vehicles is operating. A
simple form of test oscillator 116 may be included for test
purposes and the output energy may be coupled as by a winding 118
about the antenna input.
The F.M. receiver 114 may be a standard, modular form of receiver
including discriminator circuitry for generating an output via lead
120 for audio amplification in amplifier 122 and output through
loudspeaker 124. Either modulated C-W tone frequency or voice
message may be reproduced through loadspeaker 124. It is also
contemplated that the receiver output via lead 126 may be applied
to energize a relay circuit 128, e.g. a semi-conductive controlled
relay. The output from the energized relay circuit 128 will then
energize a suitablee flasher 130 and dash-mounted warning indicator
132. The relay circuit 128 may be reset by a reset circuit 136,
e.g. in the case of the semi-conductive controlled rectifier it may
be merely a momentary open switch connected to open the rectifier
cathode circuit upon actuation.
FIG. 5 illustrates one form of front panel 140 which may be
utilized with the receiver 110. Supply voltage from the vehicle
system may be applied via lead 142 through ignition 144, input
cable 146 and an input jack 148. The front panel 140 includes a
speaker grille 150 providing audible sound output and a volume
control 152 may be utilized to set the audio output in accordance
with each operator's preference. A dial indicator light 154 denotes
the ON-OFF condition of the receiver 110 and a Test-Reset switch
156 is used to effect the designated functions. Test-Reset switch
156 would preferably be a toggle-type switch of the spring return
type wherein it is normally in its off or central position with
momentary make at either side to effect the respective test or
reset functions.
In operation, the driver of an emergency vehicle or an attendant at
a road way warning station can select his mode of transmission to
mode selector switch 60 (FIG. 2). In position 62 as shown,
operation is in modulated C-W wherein tone generator 26 (FIG. 1)
provides an output tone of a predetermined number of cycles through
mode selector 24 for modulation in modulator 14 and FM transmitter
16. In the voice position 64 of mode selector switch 60, the
emergency vehicle operator or station attendant can speak into
microphone 20 whereupon mode selector 24 and modulator 14 effect
voice modulation of transmission energy from FM transmitter 16.
When it is desired to tape a recorded message, the selector switch
60 is placed on tape record position 68 whereupon mode selector 24
serves to receive voice input from microphone 20 and line or cable
22 (See FIG. 3) to apply such audio frequency energy through
amplifier 88 and record head 92 for recording on endless record 72.
The endless record 72 may be of any pre-set time length, e.g. 20
seconds message length per revolution of endless record 72. After
recording of a desired message, mode selector switch 60 is switched
to the tape transmit position 66 whereupon the selected message is
played back repeatedly for transmission without further attention
from the emergency vehicle or road way station operator. Thus, in
the tape transmit position 66 energization via lead 102 energizes
head selector 100 to enable playback head 94 such that audio
playback from endless record 72 is amplified through amplifier 98
for application through mode selector 24 to modulator 14. The
modulator 14 then effects modulation of FM transmitter 16 so that
energy conveying the repetitive recorded message is propagated from
antenna 18.
Output from the discriminator stage of FM receiver 114 should
preferably be such that relay circuit 128 will be energized in
response to reception of either modulated C-W or a voice
transmission so that flasher 130 and indicator light 132 will be
energized whenever some form of emergency warning is received. Each
individual operator is able to test his receiver by placing the
Test-Reset switch momentarily in the test position (switch 156)
whereupon test oscillator 116 of FIG. 4 is energized to couple
output energy from the oscillator through coupling coil 118 into
the RF stages of FM receiver 114 such that a characteristic output
will indicate proper operational capability to the operator.
In addition to the primary or normally applied use of the emergency
warning system, it is also contemplated that the system as
described herein could be adapted in a highway information system
such as that shown in FIG. 6. Thus, a plurality of transmit-receive
stations 170a, 170b through 170n could be positioned at designated
intervals along such as the specialized access of four- lane
highway 172. The individual transmitter-receiver stations 170a
through n may each function to cover a certain information zone
wherein all cars passing therethrough would be advised of roadway
conditions, weather reports, or other selected information.
Alternatively, transmitted energy from transmiter-receivers 170a
through 170n could also be used to energize predetermined sign
notices on visual notice boards stationed at selected intervals
along highway 172.
Each of the transmitter-receivers 170a through 170n would include a
transmitter system similar to that of FIGS. 1 and 3, i.e. including
a record-playback unit, and the stations would also include an
associated receiver which could effect message recording and
enabling of playback from a central remote station 176. The central
station 176 may include a suitable form of microphone or voice
input stage 178 operating through a modulator 180 to modulate
carrier output from a central transmitter 182 and antenna 184. The
antenna 184 may be omni-directional or highly directional as placed
in line along the roadway but, in any event, it should radiate
sufficient power to transmit to all transmitter-receiver stations
170a through 170n . A pulse code as selected at a pulse code input
stage 186 provides further pulse input to modulator 180 for the
purpose of providing an interrogation output from central
transmitter 182 for the purpose of interrogating only selected ones
of transmitter-receivers 170a through 170n to effect recording of
their designated repetitive voice message. Thus, the system will
have the capability of sending voice messages for recording on all
or only selected ones of transmitter-receiver stations 170a through
170n.
Transmitter output power at the stations 170a through n would
probably be limited to a short, minimum range power output
utilizing directional antenna as directed along highway 172. If a
vehicle operator did not care to further listen to such bulletins
or weather information, road warnings, traffic hazards, notices,
general information to motorists and the like, he has the option of
controlling his receiver through volume control; however, emergency
vehicle attention can still be communicated by means of the dash
warning light. For example, and referring again to FIG. 4, the
warning light 132 could be energized to blink and to continue to
blink until reset by the reset switch 136, i.e. to open the relay
circuit 128 sufficiently long for quenching of the semiconductive
controlled rectifier.
FIG. 7 indicates still another alternative form of receiver
structure wherein existing circuitry of the standard operating
receiver 190 may be utilized in the emergency vehicle warning
system. Thus, emergency warning transmission received via antenna
192 may be amplified through a suitable frequency selector stage
194 for discrimination in discriminator stage 196. Discriminated
output is then applied through an amplifier 198 for input to the
audio amplifier stages 200 to give visual message or audible
indication through the radio receiver loudspeaker 202. A visual
indicator 204 may still be utilized as it can receive output direct
from amplifier 198 in a manner as aforedescribed. The automobile
receive 190, as well as the frequency selector 194 and
discriminator 196, could be maintained in standby energization
whenever the auto ignition key is on since transistorized
structures used in the modern receiver art require little or no
power for operation.
The foregoing describes an emergency vehicle warning system of a
type which is highly reliable and can be constructed at minimum
cost to enable a simple and adaptable warning system of highly
automatic function. The system utilizes low powered radio frequency
energy transmission of relatively directive propagation although it
is contemplated that certain systems may utilize a selectively
energized second omni-directional antenna which could be utilized
in special circumstances such as congested downtown areas. While
the system is described primarily with respect to moving emergency
vehicles, it should be understood that present usage in many major
applications may include radio warning, information or control
systems for use along a highway right-of-way. Such special
adaptations, although in some cases requiring particular selection
of transmission and reception equipment, can easily be carried out
using the same general system design.
Changes may be made in the combination and arrangement of elements
as heretofore set forth in the specification and shown in the
drawings; it being understood that changes may be made in the
embodiments disclosed without departing from the spirit and scope
of the invention as defined in the following claims.
* * * * *