US2429607A - Radio traffic signaling system - Google Patents

Description

Oct. 28, 1947.

FIGA.

W. H. CAPEN RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet l TRANSMITTER rm/vsmrrsn n02 3 O Q I l '1 RADIATOR RECORD AMPLIFIER F AND AND zmawcm aauuumn I l RADIO TRAFFlgMfiG/ML FREQUENCY--44 AM some:

anwcns'r REcE/VER AMPLIFIER SPEAKER SPEAKER INVENTOR. W/LL/AM H. CAPEN ATT NEY.

Oct. 28, 1947.

w. H. CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 'T Sheets-Sheet 2 [as/mail FILTER l CARRIER Z1 29 25 sou/ace 1 l man 27 28 FREOUENcr I %MEf|' muLfi FILTER Sal/R05 FREOl/EMV sum:

32 L FILTER w GENERAL mama co/va/r/ou: 33 speaks? FILTER j 39 0:15am

33 35 PL/FIER FILTER ---0 34 R0012? 31 Hum '33 I INVENTOR.

36 MLLMH ans/v A El.

Oct. 28, 1947. w. H. CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 3 GENERAL I 3 ZTRAF7/Co 30 con/o 7/ iv:

V DEMODULATflR DETECTOR AMPLIFIER FILTER ROI/7E3 rmw n/rmvs 98 RECEIVER INVENTOR. WILL/AM H CAPE/V AT 0/ NEY.

Oct. 28, 1947. w, cAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 4 NFRA-RED LIGHT -50 CONTROLS CONTROLS ro PLI T0 MODULATED 221m CURRENT SOURCE TRANSMITTERs ROUTE *1 INV EN TOR. MIL/AM H. CAPEN Oct. 28; 1947. w, cAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 5 HOUSING MITTER 60 E nsmowczj T0 TRANSMITTING AHPLIFIE MPLIFIER oouau: 63 -l T0 LAMP T0 AMPUFIEM INVENTOR. W/ZL/AM H. C'APEN AT NEY.

Oct. 28, 1947. w, c p 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 6 REP ODUC\ER$ RECORD MONITOR '71 mwsnn' 11 RECORD\ T0 INTERLOCKED ban/"cuts GROUP SELECTM REPRODUCER REPRODUtE/RS F6 To sascrons GROUP /77 JUNCTION *1 *1 2 3 SELECTOR uge mu l J re Jamar/av? 2 "1 '2 "3 can/ma CENTER L INVENTOR. t mu [AM H. O4PN AMPLIFIERS 1 2 -3 4 I a/ T0 RADIATING MEANS ATT EY.

Oct. 28, 1947. w, CAPEN 2,429,607

RADIO TRAFFIC SIGNALING SYSTEM Filed March 14, 1940 7 Sheets-Sheet 7 JUNCTION con/mm CENTFWSELECTUR 20.

I l -J L ,7 GROUP W GROUP GROUP sELEcron SELECTOR SELECTOR pup T0 REHMDUCER FIG 2 92 SELECTOR-S JUNCTION CONTROL CENTER sELEcToR I I I J T0 AMPLIFIERS GROUP cRol/P GROUP SELECTOR SELECTOR SELECTOR AMPLIFIE T0 RE IPODUCER SELECTOR SELECTO ----I TO REPRgDUCE/i' \S'ELECTORS 0PEmT/av- U0 OPE/PAT/ON JELEcToRS T0 AHPL/F EH5 MPLIF/ER J T0 RADM TING MEANS GROUP REPRODMZ'ER E m 1' INVENTOR. s R WILL/AM H. CAPE/V \LAMP GROUP SELECTORS 1/ T0 GROUP sELEcTons AT J UNCT IONS ATT Patented Qct. 28, 1947 .RADIO TRAFFIC SIGNALING SYSTEM William H. Capen, Mountain Lakes, N. J., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware 1 Application March 14, 1940, Serial No. 323,883

This invention relates to arrangements for providing audible signals on automobiles and more specifically to arrangements for providing audible sigrlials on automobiles for purposes of trailic con- Traflic on the highways is becoming more and more congested and cars are being driven at increasing speed. Multiple lane super-highways are being built and complicated clover leaf and other confusing intersections are increasing in number. All routes, whether simple low speed twolane roads, complicatedmulti-lane express highways, or intricate city street intersections, are today marked only by visual signs giving route numbers or destinations.

It is very difficult for a car driver to quickly see these signs, and the driver is often confused by trafilc signals of the visual type. In order to learn which way to go, which way to turn, the driver not familiar with his surroundings must take his eyes from the road and seek a sign for his guidance. Sign hunting at intersections also slows down the particular driverwho is searching for his routes and necessarily slows down the cars following him. This usually results in unnecessary passing of one car by another. Both of these actionsare extremely dangerous and result in many collisions and needless deaths and injuries each year.

All of these difliculties can ,be overcome by transmitting audible signals to the driver. In accordance with one embodiment of my invention, radio frequency energy is transmitted by means of special radiators along the route followed by an automobile. This energy is modulated by traffic or route direction signals, under control of sound records, for example, and a receiver 'on the automobile receives the modulated energy and transforms it into audible signals. In accordance with another embodiment of my invention energy at audible or super-audible frequencies is transmitted to an automobile and received therein. Another embodiment of my invention utilizes infra-red light for transmitting trafllc directions to an automobile.

With installations of the above kind, in accord ance with my invention, there is normally more than one radiating source at each intersection.

16 Claims. (Cl. 177-337) radiating point and apparatus for connecting all of the points to a central controlling station,

' My invention will be more clearly understood by reference to the attached drawings wherein:

Fig. 1 is a representative arrangement of the transmitting sources of my invention;

Fig. 2 illustrates the circuit arrangement of a transmitter of the type shown in Fig. 1 and a receiver for use on an automobile;

Figs. 3 and 4 are modifications of the receiver shown in Fig. 2;

Fig. 5 shows in elevation, and Fig. 5a is a plan view of an ultra-high frequency radiator for directing radio frequency energy in accordance with my invention;

Fig. 6 shows a modification of the transmitter 'and receiver of Fig. 2 whereby route selection of infra-red light;

Since there are numerous intersectionsand several radiators, it is desirable to tie one radiating vention is further concerned with means for easily changing the trafiic directions given out by each system;

Fig. 12 shows transmitting and receiving lamps for use with the system shown in Figs. 11 and Fig. 13 illustrates a typical arrangement of routes and distribution of transmitters of my invention; l

Figs, 14 through 17 illustrate manual switching arrangements for changing the tramc directions transmitted to an automobile and for monitoring the transmitters giving out said direction;

Fig. 18 shows a circuit arrangement for remote- 1y controlling the transmitters at the various route or street intersections;

Fig. 19 illustrates the circuit construction of relays for use in a remote control system of Fig. 18;

Figs. 20 and 21 illustrate modifications of the remote control system of Fig. 18;

Fig. 22 illustrates a map and-pilot light arrangement forindicating the operating conditions of the transmitters in a-remotely controlled Fig. ,23 shows a circuit arrangement for si- 3 multaneously operating the pilot lights of Fig. 22 with the remote control system of Fig. 18.

As shown in Fig. 1, when two highways cross there are four ways to approach the intersection.

It is possible to transmit directions to vehicles approaching this intersection by a si gle transmitting sourc and means to identify the directions intended for the different vehicles by vehicles going south, etc. However, a system of this sort is somewhat confusing and tends towards complexity rather than simplicity, a primary object of this invention. According to one embodiment of my invention I employ radiators having different di'rectivities or radiators whose energy is restricted to a single roadway and to automatically or manually switch a transmitter from one radiator to another. While this latter system has an economic advantage, it is desirable to transmit traffic directions to all roadways continuously and simultaneously.

According to a preferred embodiment of my invention, therefore, I provide four separate transmitters I, and associated radiators I, extending along the various roadways. Although I hav shown the four transmitters at separate locations, it is possible that the transmitters may be included in a single housing and wires provided to lead their respective energies to the proper transmitting or radiating point.

At intersections where the tramc is congested and/or automobiles must proceed at a moderate rate of speed, the radiators are preferably located a few hundred feet from the intersection, and if the radiators are located along high speed highways, the spacing of the radiators from the intersection may be conveniently calculated. Suppose, for example, the average announcement takes about ten seconds. This announcement should be repeated three times to a motorist, and with an automobile speed of 60 miles per hour-=88 feet per second, the automobile should be in the range of the radiator for a distance of 30x88=2640 feet, or one-half mile. The motorist should be warned of the route or road changes about one-quarter to one-half mile before reaching the intersection. Assuming a radiator range of one-half mile and a warning distance of one-half mile before the intersection, the radiator would then be spaced one mile from the intersection. These figures are, of course, purely hypothetical and are given to illustrate the method of determining the radiator spacing from the road intersection. This type of calculation may be extended to meet any set of conditions.

Under normal operating conditions, the directions given over a period of time will be a continuous repetition of this desired information and these directions may therefore be given out by a mechanical device. A disk type record with a repeating arrangement on the reproducer arm or a sound on film reproducer may be used, but the preferred reproducer for a system of this type is a reproducer of a well known type wherein voice or other signals are recorded electromagnetically on a wire or tape of magnetic material, the signal being retained in the form of variably magnetized areas of the wire or tape. This arrangement has the advantage that the recorded signals may be erased or wiped off by running the record medium through a magnetic field thus making it possible to use it for other recordings. Such an arrangement is disclosed in Patent No. 661,619, issued to Poulson, November 13, 1900.

A transmitter having a mechanical announcing device and a receiver are shown in Fig. 2, in this 4 e figure a rcproducer 3 controlled by a record modulates a radio frequency source 4 in the amplifier and modulating stage 5. The amplifier and modulator 5, preferably of a low power type so as to restrict the radiation to a small area, feeds the radiator I which may be one or more cables buried in the roadway and running parallel therewith, a network of conductors in the roadway, or a radiator at the side of the road either on the ground or mounted on poles.

Since many broadcast receivers are already installed on automobiles, my invention will be most readily adapted to the present equipment by radiating the tramc direction signals at very low power at radio frequency. In this case the antenna already provided may be used to pick up the trafllc signals -or an auxiliary antenna may be installed in a most advantageous position in the automobile, such as, for example, under the chassis close to the roadway. The frequency at which the traffic signals are to be radiated is preferably standardized and when the driver of an automobile desires to receive trafllc signals,

it is merely necessary to tune his set to a definite frequency or to throw an auxiliary switch which brings into operation a circuit tuned to that frequency. Alternatively, a separate antenna may be provided which is connected directly to the intermediate or detector stages of the receiver, or the radiating frequency may be made equal to. the intermediate frequency, and automatic switches provided which will disconnect the broadcast signals and allow the tramc to enter the intermediate stages directly. A manual switch or automatic switch later described in detail, included in the receiver or antenna circuit, maybe provided to chang the receiver over from broadcast reception to trafilc signal reception.

The transmitted signals may be transmitted at any predetermined frequency and a separate tuned or variable receiver installed on an automobile. If the frequency used for transmitting the tramc signals is outside the rangeof the ordinary broadcast receiver, it is not necessary to install an entirely separat receiver. To reduce the cost of the installation the traillc signals may be received on an antenna 8 as shown in Fig. 3, passed through a demodulator 9 and fed to the final'amplifler stage of the broadcast receiver. A switch Ill allows the receiver output to be easily changed over from broadcast to traflic signals.

Afurther convenience for changing over from broadcast signals to trafilc signals is shown in Fig. 4. When no trafiic signals are received. a relay armature II is in a rest position, as shown,

, and connects the detector stage of the broadcast receiver to the final amplifier stage. Under these conditions, the ordinary broadcast signals are emitted in audible form from the speaker l2. When trafilc signals are received on the antenna 8, these signals are detected and demodulated by demodulator 9; these signals then pass through an amplifier i3 and rectifier ll. The output of the rectifier M, which may be of the dry type, controls a relay coil i5 which operates to pull the relay armature ii to the right against contacts l6 and II. In this position the output of the demodulator 9 is connected to the final ampli fier stage of the receiver, and trafiic signals are emitted in audible form from the speaker l2. It is apparent that the relay coil I! may be switched in or out of operation, dependent upon the will of the driver.

The energy radiated may be ultrahigh frequency energy. In this case a horn or guide it may be located beside the roadway as shown in Fig. 5 or mounted on poles or cables overhanging the roadway. These horns or guides concentrate the energy into a very narrow beam at a short distance away from the source and hence with an arrangement similar to that of Fig. 1 one field of energy will not overlap a second field transmitting diflerent signals. The horns ,or radiators may be connected to their source or sources by any well known means such as dielectric guides. To further avoid interference the antenna l9 located on the automobile may be made highly directive, so that signals coming substantially only from in front of the automobile will be received.

A driver approaching an intersection may be interested in only a single route, and if the intersection is the-junction of several routes, the identity of the driver's desired route may be lost in the mass of information given. To clearly dis- I tinguish one route from another the information concerning each route may be transmitted on a diiferent frequency. If the frequency for a given route is standardized throughout its length the driver keeps his receiver tuned to the frequency of the route desired, and as he progresses, he will receive information concerning only the route along which he is traveling.

source 23 in a modulator H2. This first reproducer 28 may contain a record or tape giving directions or information concerning minor routes. A second reproducer 25 having a. record giving information of a major route or major routes. modulates a carrier frequency source 26 at a modulator 21. The output of this modulator 21 after passing through a filter 28 modulates the high frequency source 23 simultaneously with that from 22 at the modulator H2. The combined output from N2 is fed to the radiator 29. Other reproducers may also be provided so that each reproducer gives information concerning only one route.

At the receiving end an antenna30 receives the trafllc signals and feeds them to a first detector 3I which demodulates the radio frequenc energy and produces the combined modulated sub-carriers. The output of the first demodulator 3| is connected to a group of band- pass filters 32 and 33. Filter 32 passes the modulated energy carrying the general route information, and filters 33 each pass a band of frequencies corresponding to the frequencies of the modulated carrier giving the information concerning only a single route. The output of the filters 33 connect to a selector switch 34, which in turn connects to contact point 35 and amplifier-rectifier 36. The amplifier-rectifier 36 controls a relay coil 31. When the special route signals for the route on which route switch 34 is set are below a given predetermined level, relay armature 38 is at a rest position contacting point 39. In this position the output of filter 32 is connected to detector 48 which demodulates the carrier into audible signals at the speaker 4|. When the special route signals are above a predetermined level, the output of one of the filters 33 is connected through contact point 35 and armature 38 to the detector 48, and hence only signals presenting the particular route selected will be heard at the speaker 4!. Thus when approaching an intersection where special route signals are being sent out only these signals for the route corresponding to the setting of switch 34 will be heard.

The same carrier frequency may be used several times for different individual route information as long as any two routes using this carrier do not intersect. A chart or schedule could be published giving settings or designations of the filters for radio routes throughout a large area.

Hence to follow a desired route it would only be necessary to set the automobile receiver equipment to the proper designations and all route information and important instructions will be received automatically.

If it is desired to avoid interruption of the general trafllc signals in the receiver arrangement of Fig. 6, a slow-acting relay 93 and a rectifier may be added to the output circuit of detector-amplifier 48 as shown in Fig. 7. When general trafllc signals are received through filter 32 and detected at detector-amplifier 48, relay 93 holds the circuit of coil 31 open so that individual route signals passing through one of the filters 33 will not interrupt the general traffic signals by operation of relay 31. If there is a short pause after each transmission of general trafllc information, relay 93 releases and the circuit of coil 31 is closed. Route signals from one of the filters 33 will then operate relay 31-38 transferring the input of the. detector-amplifier to that filter. To prevent operation of relay 93 by the individual route signals a contact 94 is added to relay 31. The circuit through contact 94, however, is broken slightly ahead of the making of the circuit controlled by armature 38 and its contact 35, and therefore relay '93 cannot be operated by individual route signals; When the individual route signals are discontinued. relay 31 releases and contacts 39 and 94 are closed, and the receiver is again ready for reception of general traffic signals.

The transmitting apparatus may be located at points where there is insufiicient traflic to justify continuous operation of the apparatus, and since all automobiles may not be equipped with trailic signal reception apparatus, it would not be economical to transmit the signals to all automobiles. I have therefore provided a remote control system as shown in Fig, 8 to switch on the transmitting apparatus when an automobile provided with suitable reception equipment approaches a transmitting point. A transmitter 95, which may be of small low-power type, located on an automobile having trafiic signal receiving apparatus, transmits energy to the receiver 96, the output of which controls relay 91. The receiver 95 is preferably located near the side of the road and some distance ahead of the transmitting apparatus 98 in order to reduce the power requirements of transmitter 95 and to start the transmitter before the automobile enters the signal zone. Contact 99 shorts the lines I88 which interconnect the receiving and transmitting points and thus energizes relay coil I8I. Arm I82 moves to the left against its contact closing the power circuits of the driving motor I 83 and transmitting apparatus 98. If desired, a delayed switching circuit may be employed to switch on the transmitter power and allow it to warm up before switching on the motor I83, and other controls 7 or contacts such as a motor clutch, etc. may be added to operate, simultaneously with the arm I02. A wheel I04 which is part of the transmitter reproducer mechanism preferably rotates once for each complete transmission by the record containing the traflic information and holds the arm I02 against its contact during the record transmission, and after an automobile transmitter passes out of range of receiver 00 the coil III is deenergized. After one complete revolution of the wheel the arm I02 opens the power circuits and the apparatus is ready for the next set of signals from an automobile.

If a second automobile passes the receiver 00 just before the arm I02 drops into the wheel slot, it will receive only a portion or none of the traffic signals. Two or more spaced receivers along the signal zone may then be employed .so that if a following car has passed out of range of the first control receiver one of the other receivers will be actuated to hold the arm I02 out of the slot and against its contact and insure that a second automobile will hear the directions, the transmitter normally repeating the same directions two or three times for each revolution of wheel I04. Alternatively the arrangement of Fig. 9 may supplement the parts in Fig, 8. A cam I05 is attached to the shaft of wheel I04 and has a periphery that corresponds to the portion of the wheel revolution required for the transmission of a series of trafilc signals. Suppose, for example, three repetitions of signals are transmitted for one revolution of wheel I04. Then. the periphery of cam I05 is substantially 120, not allowing for mechanical taper. If an automobile having a transmitter passes the receiver 90 of Fig. 8 too late in the transmission period to receive a complete set of traffic signals, the impulse received at receiver 95 energizes coils I01 and IN. The energization of coil I 0| has no effect during the motion of wheel I04, but coil I01 closes contact I00. Since this energization occurs during the transmission of the last series of signals, cam I05 has closed arm I 00 against contact I00 thereby shorting lines I00 and energizing coils I01 and IN from source IIO. When the slot is in front of the projection on arm I02, the power circuits do not open because arm I02 is held against its contact (or contacts) by the energized coil IN, and the transmitting apparatus repeats its cycle. After the slot has passed by the projection on arm I02, cam I05 opens the holding circuitbyallowing arm I05 to drop away from contact I09 and hence contact I08 also opens. When the transmitting apparatus is idle and an impulse at the receiver energizes coils I01 and IOI, the holding .circuit does not act to repeat the transmitting cycle since the holding circuit is opened by cam I05 during the first portion of a transmitting cycle. The length of periphery of cam I05 may, of

course, be changed to meet the requirements of the length of a set of signals, orto change the number of sets transmitted to a second automobile.

Since the energy carrying the trafllc signals is to travel only a short distance, it is possible to use electromagnetic energy of audible or superaudible frequency, or alternatively the signals may be transmitted and received by well known acoustic means using supersonic frequencies. An arrangement of the electromagnetic type is shown in Fig. 10. The information to be given out is spoken into the microphone 42 or recorded at the reproducer 43. A switch 44 connects either of these two sources to an amplifier 45 whose outvis located near the roof or under the chassis so as to be in a fairly strong field. Since traffic is passing in both directions along a given roadway, the inductive loop is confined to one-half of the roadway to avoid transmitting thesame directions to both traific lanes. The receiving loop is continually excited as long as it is in the loop area, and outside of the loop area the loop field rapidly decreases.

The traffic information may also be transmitted to the automobile by means of infra-red light. As shown in Figs. 11 and 11a an infra-red light radiator controlled by the modulating source 50, transmits signals directly to the automobile 5|. The light is received by a photocell or other known device 52. It is also possible to use other types of light to which the eye is not highly sensitive, such as visible red or blue, as long as the light is not of sumcient intensity as to be distracting.

To concentrate the light beam and to filter out unwanted light, the light source and the receiving device may be placed in housings oi' the type shown in Fig. 12. In this figure a light source 53 is placed at the focus point of a parabolic reflector 54. A lens 55 further aids in concentrating the light rays into a parallel beam. A filter 50 is interposed between the light source 53 and the lens 55, and this filter passes only a very narrow band of light of the color which it is desired to use. Thelight sensitive device 51 is contained in a similar housing as shown at the right of the figure. A lens 50 focuses the light on the device 51 and a filter -59 having the same color characteristic as the filter 50 restricts the received light to only the color which is carrying the trafilc information.

'While in the embodiments thus far described I have shown the radiators located at the intersections, it is evident that the radiators may be placed at any point along a highway. The radiators may, for example, be located at points of hazardous driving to warn of dangerous curves,

etc. The information given out may alternatively describe points of ,interest. Such auto radio road information service would be important to advertisers, and objectionable signboards could be removed and replaced by this convenient sort of information service. In these latter cases one transmitter and radiator may radiate energy to a plurality of trafilc lanes.

As an example of an application of my invention, a driver' approaching from the left along route 1, such as in Fig. 13, and nearing the first intersection, would hear from his receiving apparatus "route 1 straight ahead-route 3 right route 2 left, or reduce speed-route junction ahead. If the driver continued along route 1 at the next junction he might hear route 5, Worcester, Springfield, left-route 1, Hartford, New York, straight ahead." Similar information could be given out at the various other junctions illustrated in Fig. 13.

It is sometimes necessary to change the information given out due to weather conditions, road repairs, etc. The record may then be changed, dependent upon the conditions prevailing, or if the change in information is cyclic one or more reproducers may be provided, as shown in Fig. 14. In Fig. 14 three reproducers, each of which has a different recording, or serves as a replacement reproducer, has a plug attached which may be inserted in the jack of amplifier to change the recording being transmitted.

It a magnetic recorder and reproducer is used, a. double plug arrangement or the type shown in Fig. may be used to change the recording. A multi-sleeve double plug 63 is connected to a recording amplifier 84, a source of wipe out voltage 55, and a pilot lamp (not shown). With the plug removed from the jack the reproducer is connected directly to the transmitting amplifier. When the plug is inserted, the reproducer is disconnected from the transmitting amplifier and the recording amplifier is connected to the input of the reproducer. The lower half of the double plug 53 connects a wipe out voltage to the reproducer wipe out coil and a pilot lamp to the circuit operated by cam 66. Cam 66 revolves once for each revolution of the recording tape, and indicates by closing the contacts 61 and operating the lamp that .the recording tape is in the correct position for recording. Closing the switch 68 for a short period preceding the recording process removes the old recording from the recording tape.

In the preferred form there will be one reproducer for each of the routes approaching the route junction, and as many other reproducers as is necessary to take care of any emergency. Although each of the reproducers may have a difierent recording, a change in one recording will often aifect all of the recordings, that is, when the directions concerning one route are changed to provide for a detour, it is usually necessary to change the directions concerning the other associated routes. To facilitate the simultaneous changing of information for several interrelated routes and. to make certain that the direction given out by a transmitter cannot be changed from normal without suitable changes in the directions given out by any other transmitter located at the same junction, I have provided the interlocking switching arrangement of Fig. 16. In this figure it may be seen that the output of each of the normal reproducers A, B and C is connected to a pair ofswitch contacts associated with each of the keys A, B and C. The emergency reproducers of the groups 69, ill and H3 are respectively connected to the lower contacts of keys A, B and C. The keys operate their upper and lower contacts simultaneously, and when the upper contacts are closed, thelower contacts are open, or vice' versa. With the switches in the position shown the information contained on the recording of the normal reproducers is conveyed to the respective amplifiers. If, for some reason, itis necessary to change over from the recording of the normal reproducers 'to the recording of the reproducers in any one of the groups, a key, for

example, key A, is thrown. In this new key position the output of all the normal reproducers are removed from the amplifier inputs, and the output of the reproducers in group 69 are connected to the amplifier. In a similar manner, by leaving key A in its normal position and throwing either key B or C, the reproducers of groups Ill and 3 may be connected to the amplifier. Since changes in the directions concerning any one route will usually produce changes in directions concerning the other routes that may be predetermined, the recording of the emergency reproducers may be prepared in advance, or the recordings may be made when the emergency condition arises. In any event, when the directions concerning one route is changed by throwing a key, the directions concerning the other associated routes will also be changed, and it the recordings in the emergency group are predetermined and prepared, the correct directions for each of the routes are then automatically and simultaneously switched onto the transmitting amplifiers. This interlocking switching arrangement may be extended to include a larger number of groups or reproducers or a larger number of reproducers in a group with modifications apparent to those skilled in the art. a

In Fig. 1'7 I have shown a switching arrangement for optionally recording. monitoring or transmitting. This switching arrangement may be used in conjunction with the interlocking switches of Fig. 16 as shown, but is not necessarily restricted to use therewith. With switch II in the position shown. any reproducer is ready to transmit and the reproducer is selected by means of the interlocked switches. If it is desired to change the recording on anyone of the reproducers l or 2, a suitable wipe-out voltage is applied to that reproducer and switch ll, corresponding to that reproducer, is moved to the left. Switch 12 is moved to the recording position and the desired information is impressed upon the recording tape by means of the microphone I3 and the amplifier ll. After the recording is made, switch 12 is moved to the monitor position and by listening to the reproduction through amplifier l5 and speaker 16 it is possible to aflirm the recording made. By the same process any recording that has previously been made may also be listened to in order to ascertain its condition or information. When it is found that he recording made is correct, the switch H is returned to its transmit position, and the reproducer is ready for operation as a trafilc director.

While in the above cases I have described the reproducing and transmitting apparatus as being at the junction point, it is possible to locate all the apparatus at a central control point and convey the information to the radiators by means of connecting lines. In some installation of this sort it is then possible to use one reproducer and one recording for several junctions provided similar directions are to be given out at the different junctions. Connecting the apparatus to the radiators in this latter manner requires a considerable number of lines unless some sort of carrier system is utilized. A carrier system is somewhat objectionable since it requires apparatus not as readily constructed as that in the further embodiments of my invention.

In a preferred embodiment of my invention I locate the reproducers and the transmitting apparatus at a desired junction'point and select and remotely control the reproducing and transmitting apparatus by means of well known telephone dialing apparatus as shown in Fig. 18. A telephone 15 located at they control center controls a junction selector 16, a group selector l1, and a group of reproducer selectors I8. A telephone line, or a power line over which carrier control currents may be transmitted connects the junction selector .to the group selectors, the group selectors being located at the Junction point. The group selector I1 selects one of the group of reproducer selectors 18 or a telephone 19 which may be used in conjunction with proper circuits for two-way conversation between the control center and the junction. The reproducer selector 18 connects one of the reproducers to its respective amplifier. In addition to this means of selecting the desired reproducers at a number of junctions, the starting and stopping the operation of the transmitter may be accomplished by dialing designated digits at the central control point. At the control center the first digit dialed selects the proper trunk to the desired road junction, the second digit selects the desired group at the road junction, and the third digit selects the desired reproducer in the group and connects it to its respective amplifier. When the telephone is hung up by the operator at the control center a special key or the reproducer selector keeps the reproducer connected to its amplifier and the junction selector and group selector return to their home position. I If the reproducer selectors 18 of Fig. 18 are to keep a reproducer connected to its respective amplifier after the telephone at the control center has been hung up or replaced to its normal position, the reproducer selector cannot be of the ordinary homing type. In Fig. 19 I have shown a reproducer selector that will remain in its dialed position after the telephone at the control center has been replaced. A slow acting relay 8| does not operate when the selector arms of the group selector l! are passing over their contacts but when the group selector finally reaches its dialed position, relay 8| pulls the relay armature 82 to the down position. This action of armature 82 closes the circuit of relay coil 83 and opens the pawl 85 allowing the selector arms 86 to return to a home position. At the home position the circuit of relay coil 81 is completed, and the relay armature 84 is pulled to the right, opening the circuit of coil 83 and allowing pawl 85 to again come into operation. Selector arms 86 are now ready to be dialed into the desired position by means of a stepping relay comprising coil 88 and armature 89. When the telephone is replaced at the control center, the selector arms of group selector 1! return to their home position and coil 8| releases the armature 82. The selected reproducer is then connected to its amplifier and coil 98 is energized drawing armature 84 to the left position. Pawl 85 bears against its ratchet SI, and the selector arms 86 are held in their dialed position. The reproducer selector will remain in this position until it is again selected by the group selector, and a repetition of the above described action will ensue.

It may also be desirable to monitor the reproducer selected before the information of .that reproducer is transmitted. This further feature may be added to the reproducer selector as shown by Fig. 19. When relay coil 8| acting with group selector l1 pulls the armature 82 to the down position, a pair of contacts associated with armature 82 connect the output of the reproducer to the group selector line and hence transmits the recording to the telephone at the control end, and thus enables the operator at the control center to monitor the reproducer'selected. If the reproducer is correct, replacing the telephone at the control center returns the armature to the up position and connects the reproducer to its amplifier.

Fig. 20 shows an arrangement of selectors whereby a reproducer that is already in operation or a reproducer after it is put into operation may be monitored. In this figure an amplifier selector 92 is also connected to the output of group selector 11. The output of the amplifier selector may be connected to any part of the transmitting apparatus, but the output is preferably connected to the output of the transmitting amplifier so as to monitor the entire transmitting system. The amplifier selector 92 comes into operation when selected by the group selector I1 and remains operative until the telephone at the control center is replaced when the amplifier selector returns to its home position. In this type of monitoring arrangement, as in the others herein described, a high impedance amplifier may be connected in the lines joining the control center and the transmitters and/or at the transmitter to amplify the output signals of the monitored apparatus before and/or after transmission over the connecting lines.

Fig. 21 illustrates a circuit arrangement for recording, monitoring and transmitting. The first digit of a call from the control center selects the proper junction; the second digit selects the desired group; the third digit selects the desired reproducer; and the fourth digit selects the proper reproducer circuit for transmitting, recording, or monitoring. The operation selector is preferably constructed so that in the home position the selector arms are connected to the transmitting terminals of the reproducer and the input of the amplifier is connected through the reproducer selector to these terminals. In the second position the selector arms are connected to the recording terminals of the reproducer with the input of the amplifier disconnected by a relay associated with the operation selector, and in the third position to the output terminals of the reproducer with the transmitting amplifier input disconnected. To connect the amplifier input to the reproducer at only the home position, it is also possible to add an extra arm or contact to the operation selector that is operative in only the home position. With this form of operation selector, it is possible to record, and monitor at the reproducer without transmitting the information to the roadway radiators. The reproducer selector shown in this figure performs the same function as that of Fig. 18, and the amplifier selector is similar to the amplifier selector of Fig. 20.

In any remote control system it is desirable to know that the reproducer or transmitter is in operation. A convenient system for maintaining a constant check on the reproducers or transmitters in operation is shown in Fig. 22. A map 88 containing a plan view of all the roads or routes under the control of a particular control center is studded with lamps located at positions corresponding to the actual positions of the transmitters, and these lamps are turned on or off by special switches acting with the operation or non-operation of the transmitters. Since there maybe more than one reproducer at each transmitter, a plurality of lamps may be located at the map junctions to correspond to the exact location of the transmitters, or lamps may be located behind a single pilot lens, these lamps giving a different color illumingion for each of the individual reproducers. g5

When the reproducers arid transmitters are manually controlled, the lamps of Fig. 22 may be operated by switches simultaneously actuated with the manual switches. When lamps are used with the dialing arrangement of Fig. 18, a group selector and reproducer selector shouldbe provided at the control center to operate in conjunction with the junction selector and simultaneously reproduce the switching operations of the junction point'group selector and reproducer selector. An arrangement of this type is shown in Fig. 23 wherein group selector I1 and reproducer selector 18' perform operations that duplicate the 13 switching actions of group selector I1 and reproducer selector 18 of Fig. 18.

In all of the arrangements herein described it is understood that additional switches may be included that operate simultaneously with the automatic ormanual switches to make any or all of the reproducers or amplifiers operative or inoperative. In the remote control arrangement, while I have described the apparatus as being at fixed definite location, it is to be understood that the location of the apparatus is not restricted but that the apparatus may be located entirely at the center controlling point or at the junction point.

While I have described particular embodiments of my invention for purposes of illustration, it will be understood that various modifications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

What is claimed is:

1. A system for transmitting signals along highways to vehicles traveling thereon and receiving said signals on said vehicles, comprising a plurality of signal sources, transmitters of radio frequency energy connected thereto each comprising a plurality of radio frequency generators, each of said generators operating at different predetermined frequencies and being controlled by one of said sources, radiating means associated with said transmitters for radiating radio frequency energy substantially only within the width of said highways and along a short distance thereof, and receivers on said vehicles for receiving said energy each comprising a plurality of detector stages, filters connected to the output thereof, each filter passing a different band of frequencies, an amplifier having an input and output, the input normally being connected to one of said filters, a switch for selectively connecting to any one of the remaining filters, automatic switching means under control of signals passed by the filter selected by said switch for changing the input connections of said amplifier from normal to the output of said selected filter when energy of the frequency passed thereby is received, and speaker means connected to the output of said amplifier.

2. A system for transmitting signals along highways to vehicles traveling thereon and receiving said signals on said vehicles, comprising a plurality of signal sources, transmitters of radio frequency energy connected thereto each comprising a plurality of carrier frequency generators, each of said generators operating at different pre determined frequencies and being controlled by one of said sources, and a generator of radio frequency energy modulated by said carrier frequency generator, radiating means associated with said transmitters for radiating radio frequency energy substantially only within the width of said highways and along a short distance thereof, and receivers on said vehicles for receivin said radiated energy each comprising a demodulator stage, band-pass filters connected to the output thereof, each filter passing one of said carrier frequencies. a detector and amplifier having an input and output, the input normally being connected to one of said filters, a switch for se lectively connecting to any one of the remaining filters, automatic switching means under control of signals passed by the filter selected bysaid switch for changing the input connections of said amplifier from normal to the output of said sefurther comprises means for rendering said further switching means inoperative in response to receipt of energy of the frequency passed by said selected filter prior to receipt of energy of the frequency passed by said normal filter.

4. In a system for transmitting signals along highways to vehicles traveling thereon and receiving said signals on said vehicles comprising a signal transmitter, means for rendering said transmitter operative in response to signals from said vehicles comprising a transmitter on said vehicle, a receiver for energy from the transmitter on said vehicle at a predetermined position with respect to said highways and spaced from said signal transmitter, switching means for energizing said signal transmitter, control means responsive to the output of said receiver for operating said switching means to energize said signal transmitter, and means for maintaining said first mentioned switching means operative over a predetermined period of time.

5. A system according to claim 4 comprising further switching means for maintaining said first mentioned switching means operative over a second predetermined period of time upon the receipt of energy in said receiver during said first predetermined period.

6. A system for transmitting signals along high.- ways to vehicles traveling thereon and receiving said signals on said vehicles comprising a plurality of transmitters, a plurality of signal sources associated with each of said transmitters, switching means remotely controlled from a common station for selectively connecting any of the signal sources associated with a transmitter to the input thereof, a plurality of radiating means associated with said transmitters for radiating energy substantially only within the width of said highway and along a short distance thereof, the energy radiated along one highway having negligible effect in other highways and in other portions of the same highway, receivers on said vehicles for receiving said energy, and means connected to the outputs of said receivers for emitting audible signals.

7. A system according to claim 6 wherein the operation of any one of said switching means simultaneously changes each of the signal sources connected to the transmitters.

8. A system according to claim 6 wherein said signal sources comprise records and reproducing devices and said system further comprises recording apparatus, monitoring apparatus, and switching means for selectively connecting said reproducingdevices to said recording apparatus, monitoring apparatus, and said first mentioned switching means.

9. In a system for transmitting Signals along intersecting highways to vehicles traveling thereon and receiving said signals on said vehicles comprising a plurality of groups of transmitters and associated reproducers at each of the intersections of said highways, a system for remote control thereof comprising a controlling center relected filter when energy of the frequency passed mote from at leastone of said intersections comprising impulse transmitting apparatus, intersection selecting means under control or said impulse transmitting apparatus, group selecting means under control of said intersection selecting means and operated by said apparatus, and reproducer selecting means under control of said group selecting means and operated by said apparatus for connecting a predetermined reproducer to its associated transmitter.

10. A system according to claim 9 further comprising a map of said highways and intersections and lamps under control of said selecting means located on said map in positions corresponding to the locations of said transmitters, said lamps indicating the operating conditions oi said transmitters.

11. A system according to claim 9 further comprising a map of said highways and intersections and lamps under control of said selecting means located on said map in positions corresponding to the locations of said groups, said lamps indicating the operating conditions of said transmitters and reproducers.

12. A system according to claim 9 wherein said reproducer selecting means comprises switching means for disconnecting a reproducer from an associated transmitter, switching means for connecting a predetermined reproducer to its associated transmitter, and switching means for maintaining said predetermined reproducer connected to its transmitter after said reproducer selecting means is released by said group selecting means.

13. A system according to claim 9 wherein said controlling center further comprises speech transmitting and receiving apparatus and said reproducer selecting means further comprises switching means for connecting the output of said predetermined reproducer to said speech receiving apparatus prior to connection to its associated transmitter and for disconnecting the output thereof from said speech receiving apparatus upon connection to its associated transmitter.

14. A system according to claim 9 wherein said controlling center further comprises speech transmitting and receiving apparatus and said remote control system further comprises operation selecting means under control of said reproducer selecting means for selectively connecting said speech transmitting apparatus to the input of said predetermined reproducer, said speech receiving apparatus to the output of said predetermined reproducer, and the output of said predetermined reproducer to said reproducer selector and transmitter. the input of said transmitter being disconnected from said predetermined reproducer upon connection of said speech transmitting and receiving apparatus to said predetermined reproducer.

15. In a trafilc signaling system having a transmitter for communicating with tramc proceeding through a. predetermined signaling zone, a signal record means electrically connected to said transmitter to effect modulation of said transmitter by audio-frequency signal energy impressed on said signal record means, a timing device for controlling duration of operation of said signal record means to establish a signaling'cycle of predetermined duration, said signaling cycle being substantially equivalent to the length oi. time required for trafllc to negotiate the signaling zone, and means electrically connected to said transmitter for establishing a. definite signaling field primarily embracing the signaling zone.

16. In a. traflic signaling system, a carrier wave transmitter, automatic means for modulating carrier wave energy from said transmitter by prerecorded audio-frequency signal energy, said modulating means including a magnetic signal record device having a strip record-bearing medium of endless loop type and having a magnetic signal record pickup and amplifying means cooperatively associated therewith, said magnetic record device having circuits normally operative to eilect automatic repetitive transmission of recorded intelligence in a transmitting cycle of predetermined duration, and electric switching means under control of an electric timing mechanism having a control period of predetermined duration for connecting circuits of said magnetic record device to eflect obliteration of a magnetic signal record on said record bearing medium concurrently with the recording of a new signal record on said record-bearing medium, said control period being initiated by manually operable switching means interconnected with said electric switching means and said electric timing mechanism, said control period being automatically terminated by said electric timing mechanism.

WILLIAM H. CAPEN.

REFERENCES CITED The following references are of record in the Halstead III Sept. 9, 1941

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