US2015612A - Traffic signal - Google Patents

Description

Sept. 24, 1935'. c. ADLER, JR ,0

TRAFFIC SIGNAL i Filed Jan. 13, 19:52 I s Sheets-Sheet 1 Patented Sept. 24, 1935 UNITED STATES OFFICE l v 2,015,612 1 g 'raamo SIGNAL Y Charles Adler, In, Baltimore, 4 v ApplicationJanuary 13,1932, Serial No. 535420 'zolrin'm...(o1.1-1-1--,s: x-nl vv The present invention relates to trafllc signal started but is incompleted, the sounds created j systems, and more particularly comprises an im-' by the succeeding vehicle'will halt suchtransfer provement upon signals of that character which until the sound vibrations "are no ,longer sum are generally spoken of as traflic actuated. ciently intense to be received by the means at- 5 In the present case I employ a trailic actuated the intersection when the transfer will be conmeans, namelyasound box, which is arranged in. ti'nued.-, e the highwaysin advanc'eof the intersection which It is a further object'of the invention to proit is desired to control. Cooperating with such vide a mechanism wherein continuous subsequent trafllc actuatedmeans, but independent thereof, j actuation ofthe same'trafllc element in any one I 'are means arranged at the .intersection 'which road will have no effect upon the 'mechanismqo are directly sensitiveto sound waves created'by for transferring right (if-way. a. t v the passage of vehicles. It is therefore the pri- I An additional object of the. invention is to; mary object of the invention to provide a traffic provide l mp ir ui *w y' the, sisnal-jwill control system wherein the conditions prevailing operate'on the split amber pri'nciplef n n Y at the intersection will govern the transfer of A furtherobject ofthe inventionis topro- 5 the stop and go indication back and forth; In vide a signal system which can be msqemn other words, the transfer in accordance with automatic, orcaus'ed to asareverting'isignal the present system will 'talr'epla'ce substantially without changing the rnecl anisrn'; I instantaneously with the actuation of the traffic I It is, however, the prime purpose-of this in:

actuated element, but by reason of the' means at vention to avoid the use of any timing m en= the intersection, such immediate v transfer will anism and the signal whichhasno normal is f be prevented or halted at any point, i'. e.', sub-i completely controlled by name, beinggcharacter; ordinated between the movement of the signal ized y fre d mfromany so-called minimum or mechanism to present stop and 'go; j m m an avl 'aln immediate operable It will therefore, be seen that the present ins u d actuat d sisnalchansing means subordi 25 vention seeks to eliminate, and does eliminate, an d; h w veri t0 as parately.operablecontrol timing such as has been heretofore practicedin means which is superior "to said first named connection'with traihc actuated systems. There ans, fl y, t in ep nden 8nd is no maximum or minimum period for the parperior control is also sound actuated;

iticular signal indications as understood in the "Referring to t d aw ngs, I have illustrated in v art, and in fact the signal indications when no F SI 1 a i a O my System, and in Figurez,x traffic is present, are transferred immediately a f her dla ram ofa modification.

upon actuation'of the trafllc actuated element, F r s 3' and 4 are detailviews ofthe' name and where tr'aflic is present and sound waves are flctuatlednelements} I n being created at the intersection, suchsound I v illustreted'the invention nnl 't an 35,

waves control the transfer, i. e.," are superior intersection hfiv'ingfih nve s ng oadways A and-there'is no definite time period for either nd Preferably i hf w ys I road leading to the intersection. place a traffic actuated element'which is disposed The present invention is practicable because in ad n the intersection; These n me 5 40 -it has often been observed that vehicles apmated elements ll d eas lfand 2 'in proach the intersection in a stream and as long street A, and 3 and l in street B. They wmw e as such vehicles are sufficiently close together, re sp fi y 'hereflf erlbut in the the soundvibrations created by them will pre- Present instance comprise elongated hollow sealed vent any transfer of the signal to the other road. boxes 1 re p s w h interposed i the? When, however, a gap occurs in the vehicle street .with theirtop surfaoes'ilush therewith, and 45 stream, as experience indicates is the usual conh associated microphones w e y the lvib'ra dition of moving traffic, an actuation of the-traflic t n created y v hicles moving over the hollow; element onthe other; intersection will instantly box w l b t an to h? is c em mtransfer the signal and halt'traillc in the line of e so d bo e an 2 areeormected by a wire the trafllc stream.- 5 to each other andare connected in series by the 50 Asa condition, however, to such a transfer, wires 6; and 'l with the primary of a transformer if the gap is not sufficiently large, or if the A ryfl1Sin 1l S dinthelinetothe'p flsounds created by the succeeding vehicle are suilimary. The elements I and A are similarly conciently intense, actuation of the traffic element nected to the'prlmary of a transformer 'll; The will not causea transfer, or if the transfer has 1 secondary or microphonecircuit includes the sec- 55 the usual electromagnet I 3 and armature l4. The

armature I4 is connected by a wire II! to a battery or other source of direct current 18. The armature also rests at its other end upon a contact II which leads by a wire I8 to a contact member l8 associated with a relay 28 comprising the usual electromagnet 2| and armature 22. There is also connected to the battery by the wire 23 through contact 82a second, armature 24 which is associated with the armature 22 and electromagnet 2! of relay 28. The armature 24 is connected by a wire 25 to a second armature 28 which is 'connectedthrough contact 82' to a wire 21 leading to an electromagnet 28. This electromagnet 28 is associated with a brake mechanism comprising an armature 28 mounted at the end 01' a pivoted arm 38 from which armature extends a leg 8i carrying a stop lever 32.- The stop lever 32 has an upstanding brake shoe 33, and at one end is provided with a tapered foot 34. The electromagnet 28 is normally energized and thereiore supports the trip lever 32 in elevated position.

The braking mechanism just described is adapted to engage a disc 35 which is rotated by means of an induction motor 36. The induction motor is wired to a source of alternating current through the wire 31 and is also connected by a 88 to the armature 39 of a relay 40 having an electromagnet 4|, which armature is normally nected by a train of gearing 41 to a shaft 48' carrying insulated contact arms 49 and 50, thecontact arm 58 extending beyond the varm 48. Both arms 48 and 58 are connected through leads 83-84 to battery l8 atall times.

The contact 5|) is adapted to engage respectively thecontacts 5|. and 52, which are diametrically disposed about the path of rotary movement of such contacts. The contact segment 52 is connected by a wire 53 with a relay 54 comprising an electromagnet 55 and an armature 56. when the contact 58 is in engagement with the segment 52, it will energize the magnet 55 and lift the armature 55 to engage, a contact 51 leadingto the amber light 58 on road B. When the contact 58 engages the segment 5|, the relay 58 comprising electromagnet 68 is energized to attract the armature 8| to engage the contact 52 which leads to the amber light 53 on road A. The contact 48 engages a'circular contact surface which is divided into segments a and b defined by the diametrically disposed insulated points 64. When the contact 48 engages the segment b, as shown in the drawings, the relay 65 has its electromagnet 66 energized to attract the armature 61 into engagement with contact 68, which leads to the green light 69 on road B. The red indication 18 on road A is in multiple with the circuit to the green light 88 and consequently when the green on road B is illuminated, the red on road A will likewise be illuminated. When the contact 49 engages the contact segment a, the electromagnet 65 is deenergized and the armature 61 drops into engagement with contact 1| which is connected to the green light 12 on road A and, as shown, the red light 13 on road B is in multiple with the circuit to green light 12 so that illumination of green light 12 on road A will simultaneously illuminate red light 13 on road 13.

It is to be observed that by reason of the position of the amber segment 52, coinciding as it does with a portion of segment b, that in the a transfer from road B to road A, the respective contacts 48 and 50 will engage respectively the contactv segment 22 and the amber segment 52. Thus in transferring right at way mm road B, there will appear with the greenon road B also an amber indication since the lights 58 and 69 will both be illuminated.' At the same time, however, the red light 18 on road A will remain illuminated until the contact 48 engages the contact segment a when the amber and green on road B will be 15 extinguished and simultaneously red will appear on road B and green on road A.

As stated, the induction motor-circuit is normally made through wire 31 from the source of alternating current and wire 88 leading to armature 38 and ground. The relay 48 is associated with a microphone 15 having a megaphone 16- associated therewith, one side of the microphone circuit being suitably grounded, as at 11, and the other side leading by a wire 13 to the battery I8. In the line 18 is a resistance 18 forming a primary transformer coil cooperating with a secondary coil 88 having its terminals connected with th eiectromagnet 4|.

The operation of the invention will now be described, and it is to be observed that with the diagram shown in Figure Lthe'green light 69 and the red light 10 are illuminated, the contact 48. engaging the contact segment I), and hence the. signal is set to move traflic along road B, and halt traflic on road A.

Upon avehicle passing from one of the traflic actuated elements I- or 2, 'or both oi them, an alternating E. M. F. is set up in the secondary, ll oi the circuit to relay l2, which attracts the arma 4 ture l4 and breaks the circuit from the battery through this armature and wire l8 to electromag-' net 2!. The electromagnet being thus de-energized, permits the armature 22 to drop from the; contact i8 and the armature 24 to drop from the contact 82. The armatures 22 and 24 are mechanically associated withthe relay 20 and simultaneously operated thereby. I

When the armature 24 drops, the circuit from' the battery through the wire 28 tothe contact 0 82 is broken, and hence the circuit from the bat-- tery through wire 21 to' electromagnet 28 is broken, de-energizing this electromagnet and permitting the trip lever to drop out of engage ment with the pin 48. Since the motor 35 15 constantly energized and is only restrained by the brake shoe 33, it will at once through the gear 43, disc 44 and associated gearing, act to revolve the shaft 48. As the shaft 48 revolves, the contacts 49 and move toward the insulated 00 points 64 and the-split amber indication is given on road B with the green and amber. lights energized due to. engagement of contact members 48 and 50 with segment I) and amber segment 52.

As the insulated contact arms are rotated, and 85 pass into contact with segment a, the green light on road A is illuminated and the red light on road B likewise illuminated. At the same time,

a circuit is established through wire 83 which is connected to the contact members 49 and. 50 and battery l6 through wire 84, on the one hand, and wire 85 which is connected to the contact segment a, and to relay 2D and its ground on the other hand. This circuit will energize the electromagnet 2! as soon as contact 49 engages conengage the periphery of the disc 35 and stop further rotation of the parts. Hence the signal will havebeen transferred toroad A.

, It will be understood, of course, that as soon as vibrations created by passage of a vehicle over the sound elements I and 2 cease, the armature II will drop into engagement'with contact I1 and the circuit will be re-established. In this connection, it will be noted that with the signal now set for go on road A, the'passage vehicles over the sound elements in road A will not circuit is now made through t produce any transfer movement, forwhile the armature H will'jiggle due to the vibrations set up by the sound elements i and 2, the circuit to the relay 2!! is independent t reof since said contact segment a, and therefore armature 24 -will not drop. Hence a stream of vehicles may continue to pass over road A without ,ail'ecting the signal unless one of the sound actuatedfelements 3 or on roadBis actuated.

The purpose of the microphone and associated circuit will now be described. At this point, however, it should be stated that the disc and the associated mechanism whereby the shaft 48 is operated, are simply actuating means and have for trafllc purposesno' timing value. Thus actuation of either of the sound actuated members i, 2, 3, and l will'cause a sub-' stantially immediate transfer of the signal back and forth between the roadways, and whatever a time period may be required to effect such transintersecting highways.

ground at the intersection Also, I may'use a single microphone positioned in the box or housin: for the signal mechanism which is disposed 5 at the intersection. Again, where a centrally disposed signal box is employed, that is, one situated on an island in the center of the intersectiom'I may place one or more microphones in the proper position sons to be exposed to travelling on both The sensitivity of the microphone may iusted and controlled by a suitable regulable resistance 90, asshown.

' vAs set forth, the normal circuit to the induction'motorjt is made through the armature which is grounded at 42. However, assuming that vehicles are passing cm road A, they willset up sound vibrations, as for example those created by the motor, as well as any incident to the character and condition of the machine, which vibrations will be caught by the microphone It to induce an alternating E. M. F. into the secondary ll to energize the electromagnet 4i and attract the armature to thereby break the circuit to the motor 36.

I will now describe the conditions under which v The present signal in addition permits the the'micro'phone 15 operates to render the trafljlc signal efficient.

In the-first problem, where traflic is light on both streets, if the "go signal is onroad is, ac-

The second problem is where a stream of trame is passing on road A and'tramc desires to cross "road B. In this situation, as long'as vibrations are set up at the intersection-to which i0.

phone is sensitive, actuation 'of'the' elements 3 and l, is subordinate, and'while'it break the circuit and de-energize thebr'ake magnet 20, can not cause a transfer since the 1 motor circuit through armature the broken because the armail;

ture 38 will be attracted bythe electromagnet 4i and hence microphone I ll and associated mechanism is superior. 'Iherefore,'the-signal will not transfer until the sounds eitherceaseor microphone.

With this conditionin trafllc engineers have observed from experience that in trafllc streams there'is usually, a gap,'and hence if one,

tuatlon of "elements i and 2 will immediat transfer it to road A, vice are of less intensity than sensitivity of the-l0; I

of elements 8 or 4 have been actuatedfwhenu this gap occurs the sound" vibrations either cease or become of decreased-intensity, the armature 39 will drop and the motorligwill' operate to transfer-right'of way. of thefact that the actuating mechanism comprising the- '30;

disc 35 associated parts to the shaft 49 move too rapidly to have anytrafllc cone trol value, advantage can be taken of the gap to transfer the signal without dimculty;

However, it is necessary to safeguard sunburn- 35- mediate transfer as where the gap-betweenthe vehicles is relatively short, and hence where such a short opening in the trailicstream exists, the vibrations set upby the succeeding vehicle 612- flningthe gap will be" at once .picked up by the 40 I microphone to lift thearmature 39 and stop the operation of the motor,and hence the transfer of the signal. Thus such transfer may bev halted,

. i. e., is subordinated atany point in therotating movement of the shaft 48 to the action of the, superior'microphone circuit. Asga result, trafllc waiting to cross the intersection must wait until another gap occurs-inthe stream on road A, when the armature will drop'and the motor willcontinue to operate the parts.

, Of course, the same result 5 is a stream of traffic. on road 13 and eitherof the 7 or sound waves, or such sound waves-as are present are not sumciently intense to be picked upby the microphone.. r

transfer-to be interrupted at any point in the Lrotation of the shaft 48, with the result that the transfer although released may be retarded whena I ever the sound-vibrationsare suchas will be Y picked up by the microphone. As theresult, there f7 is no definite timeperiod for the rotation of the shaft inresponse to anactuationof the Mo elements.

In some cases there is a natural tendency of the I l' disc V3! to coast slightly,-which wmact to move" the shaft in the direction. of transfer, and of course the vibrations may be such that the armature 88 will jiggle to intermittently move the shaft 48 in the direction of, transfer.

It is these important characteristics of the present invention which makeit as near to the presence of a trafllcoflicer as it is possible for a machine to be.

The present invention can be made into an m. automatic reverting signal independent of the sound means by interposing a manual switch 88 I in the lead II or the lead M which switch when thrown open will render the sound means I, 2, 3, 4 and 18, I8 ineffective.

u. In this manner, if it is desired to have the signal indication normally green on road A and the mechanism operable to transfer to green on road B, the switch 88 in lead 8| will be opened and permitted to remain so. Thereupon, when {9 the sound elements 8 or 4 on road B are actuated, relay I2 attracts the armature I4 and breaks the circuit through lead H to relay 28', whereupon armatures 22' and 26 drop and the electromagnet 28 is de-energized. The brakelever then 2| :dropsiand-the shaft 48 rotates to transfer the signal to road B. Electromagnet 85 being thus energized by connection to the contact segment b attracts not only the armature but also the armature 86, establishinga circuit from the.

30 battery I8 through lead 84, armature 88, lead-8l to the relay 28', thereby attracting the armatures 22' and 28.

In the normal operationof the invention with both switches 85 closed, this would re -establish the as circuit through the line from battery I8 and leads i8--8224-25282l to energize. solenoid 88 raising brake lever 82 and fix thesignal for road B as shown in the drawings, the operation of the parts for'each road being the same.

However, with switch 85 in lead 8I open, such circuit cannot be established except when contact 48 engages segment a, since armature 24 only contacts with contact 82 when relay 28 is energized, and the latter is only energized when green'is given on road A, i. e., through battery II, lead 84, 88, contact 48, segment a, lead 85 to relay 28.

'Thus the contact arm 49 will, in the absence of actuation of relay 48 through sound vibrations 0 which, like the other sound actuated means, is rendered ineffective, continuously move over thesegment I), and return the signal to road A when the circuit above mentioned will be completed and solenoid 28 energized. g5 The speed at which the disc 35 rotates will be such that notwithstanding it must make a complete revolution to return the green or right of way to road A in the vehicle operated reverting type of signal in accordance with this invention, 50 the time period will not be comparable to that now permitted or required in normal traflic operation. Dependence is therefore placed upon the superior microphone system I5 disposed adjacent the intersection which, in accordance with the 55- sound waves or vibrations created by the passage of moving vehicles, will control the transfer of the signal indication. Hence it will be seen that in this vehicle actuated reverting signal no predetermined minimum or maximum time periods 70 tare possible and the transfer is solely regulable by the continuity of the sound waves and their intensity relative to the microphone. system. In other words, the vehicle actuated reverting system has no compellable features such as under- 75 I stood in the art. Thus the signal will not change to give the green to road B as long as the sound waves at the intersection are such as to maintain the electromagnet 4| energizedand hence there is nothing resembling a predetermined maximum.

Similarly if the brake lever has been released by 5 actuation on road B, the rate of transfer can be interrupted and delayed in accordance with the sound waves at the, intersection again excluding the uselof any predetermined maximum. when the signal indication has been given to road B it will remain on road B only as long as the intensity of the sound waves causes energizetion of electromagnet H in the event of actuation of eitherthe element I or 2 in row A. Hence,

there is no condition resembling the so-called minimum. When it starts to revert, this reversion may be halted or delayed as the conditions at the intersection, namely the intensity of the vibrations or sound waves, require.

The invention is capable of acting as a full automatic signal by opening both of the switches 85 and then changing the gear ratio between the motor and. shaft 48 to produce an appropriate timing, in which event solenoid 28 can never be energized.

' signal operation.

It will be understood that the ratio of the gearing between the disc44 and the shaft 48 is such that the arm carrying the contacts 48 and 88 will rotate at the same speed as the disc 44. This may be varied, if desired, but it is preferred that they have the same speed of rotation.

Referring to Figure 2, I have illustrated a construction which is substantially similar to that shown in Figure l, but in which a motor, pref- 5, erably a series motor I88, drives the shaft 48 to rotate the contact members 48 and88.

The signal being set for go on road B, it is to be observed that actuation of either of the traflic actuated elements I, 2, will cause the ar- '56 mature ml of relay I82 to be attracted, thereby breaking the circuit from the battery to the electromagnet I88 of relay I84. This will deenergize the electromagnetand permit the armature I85 thereof and armature I88 which is mechanically connected with armature I88, to drop. Armature I88 will engage the contact I8'I which leads to the armature I88 of microphone relay I88. Armature I88 is electrically connected with the motor through lead II8. Thus the circuit to to the motor includes the source of alternating current, armature I86, and the circuit just described. The control of the motor is obtained in the same .manner as heretofore described in connection with the microphone 18. Since the insulated an for example byimposing gearing between"the motor and shaft 48. t v

In the illustration' givenin-Figure 2','the green light on road B is operatingfbut the transfer of right of way is substantially similar to that setforth in connection with Figure l. As with theconstruction shown in Figure l,- the mechanism which is operated by'actuation of the respective sound elements for the respective streets 1d of the intersectionis similar, and'I have therefore simply described the operation oi the apparatus as far-as possible to effect transfer of right of way from road B to road A; it being understood that the circuits to the lamps are identical with the prior described arrangement;

In connection with the construction of Figure 2, it will be understood that the motor will-stop whenever the contact 40 engages either'of the segments a' or I), this being due to the circuits established on the one'hand through 'line 'III' to relay II2, whereby the circuit from thebattery through line 3, armature H4 and line II5 to relay I04 is completed, breaking the contact between armature I06 and contact I0'I. In the same manner, when the contact 40. engages the segment a, the motorcir'cuit is broken by reason "of the energization of relay I04 through the medium of line I I6 and line I I 3 leading from the bat- .tery through line I II to the contactor and lifting relayI06.

' Referring to Figure 1, and providing there are no sound wavesat the'intersection such as would afi'ect'the relay 40, movement over one of the sound boxes in one highway will startthe trans- 051 ferring of the signal, and ifimmediately there-.

after the sound box in the other int'ersectingroad be actuated, the brake will not be applied.

will be'cle'ar, since if the element 2 be actuated,

cent pin or 46, element3 be operated, the siga up nal will return to give right of way" to road B.

This-is due to the fact that while armature 24 may be picked up when the contact 49 is on segment a, armature 26 cannot be picked up until the contact 48 is on segment b, and consequently the electromagnet 28 will remain de-energized.

Of course, this transfer of right of way in accordance with my invention will be too rapid for practical traffic regulation, and in actual operation the microphone 15 will pick up vibrations 55 from the first car and delay or retard the return of the signal to road B since the induction motor will at least, if there be only a single car crossing road A, be halted or stopped for suflicient time to properly control the intersection and prevent 00 any dangerous result. As will be observed, the

signal is operated by independent sound actuated means, (one subordinate, namely the. transferring means, actuated by elements I, 2, 3, and 4, and the other superior, namely the microphone 1'06 control "I5-394I) and is free from any minimum or maximum timing. Furthermore, the signal does not require anynormal.

It will be understood that a single microphone 15 may be employed, and where I employ two or more microphones, whether they be positioned at the comers of the intersection or on an island in the center, I prefer to connect them in series.

In the drawings, I have indicated the batteries by the numerals D. C., and the source of operating current for the motor as A. 0., although it will be understood current-can em.-

playedwhere available.

" The construction shown Figure may be.

adapted for a reverting signal or fullautomatic signal by interposing switches similar to those *5 of Figure-1 and changing the gear ratio between the motor and shaft 4a- Innormal operatiomno timing is providedfor, the signal being solely responsive to conditions at the intersectiongand in the absence of soundsor m vibrations at the intersection, the j'actuating means has no trafilc control value. :In this; man-' ner; I obviate the use of such objections .as; time extension, since nominimum or maximum ispro- M vided forin normalop'eration and transfer being 16' solely under control of microphone. I5. is; ;-in-

The microphone-or. microphones maybe sensitive to vibrations, soundiwaves, orboth, and ad-.

justed' to pick up and handleall character of con- 20.

ditions prevailing at the .intersection;. When used as a reverting signaLtmmc elementsin one" street; will notbe necessarmeswlll be-understood- 0 Referring toFigures 3 the construction 2 5 and 4 will..-be.explained.-

. .1 Each" of these elements makes use of .an outer shell comprising abottom' I22;.'-two side-walls I20 and two end walls I24 and I25. This shell, in practice, isof a rectangular-shape and-is. about five feet ten inches long, more'or less; about-ten or-eleveninchesin width and between 'nineand of the sound-producinghighway elements ,Ij;.2,; l,

ten inches in heightmIn practice, this shell is 1 embedded in-the' highway.

I "A-cover l26 is-providedover thetop of the 1 hollow shell and fromtheunder side of this cover there'depends an inner shell I21. "This inner shell is formed of metal that is very much thinner than that of the outer shell: and isclosed'at the 40- bottom, sides,-one end and of course at the top,

because its upper edges} are preferablyi'welded to the under side-of the cover I25. :'I'here' is no' contact between the*sides,- ends,*or bottomQoi'cthis inner "shell I21 and thesides, ends 'or bottcm of 46- the' outer shell and. saidinner. shell ls absolutely hollow. V V I One end I20 of the inner shell has a circular opening I20 therein and a microphone structure I30 is attached to said endover said opening- '50 t This microphone structure projects through an opening in the end wall I25 of the oute'rfshell and this projecting portion of the said microphone is conflned in a separate end-chamber Ill formed on the end of the outer shell andacces- 55 sible by means of a detachable cover I32, so that access may be gained tothe microphone'for the purpose of connecting or disconnecting the wires leading thereto. These various wir'es,-in practice, are carried through pipes to one wall Ill of 50 the microphone chamber.

I havefound in practice that it is 'quitedesirable to provide a second covering over the cover I26 of the shell because sound vibrations in the inner shell are so readily set up that a heavy rain, 65 or hail beating down directly on the cover I20 will cause vibrations atthe microphones which will cause an operation of the signal mechanism. To

- avoidthis, I use a .rectangularshim I34 around 7 and cover so that when rain or hail beat down on 75 the steel plate, there will be no direct transmission of sound to the inner. shell.

A rectangular frame I31 is bolted through the marginal edges of the saw-steel plate .tothe cover to hold the said plate in spaced relation above the cover. w

It is, therefore,to be understood that each of the sound-producing highway elements has the form of one hollow receptacle within another, and that each element is embedded in. the highw y. preferably with the rectangular frame I31 flush with the upper highway surface, so that the wheels of a vehicle may pass overthe frame and the saw-steel plate without jolt or jar to a vehicle or its occupants. 1

It is also to be understood-that there are no movable'parts or switches that have any movement as the result of actual contact with the vehicle wheels and, therefore, nothing to get out of order or requiring constant maintenance as is the case where movable switch contacts are actuated by the pasage of vehicles.

I claim:

l. A signal system for intersecting trafllc lanes having a right-of-way signal indication for separate display to saidulanes; means actuated by tramc on one lane to display the right-of-way to that lane, and means actuated by the sound of trafllc on the lane having the right-of-way for maintaining such right-of-way so long as such sound actuates the last said means.

2. A. signal system for intersecting trafllc lanes having a right-of-way signal indication for separate display to said lanes, means actuated by I trafllc passing in said lanes to transfer right of way back and forth between said lanes, and means actuated by thesound oftrailic on the lane having the right-of-way for maintaining such right-of-way so long as such sound actuates the last said means.

wayfback and forth between said lanes, said means comprising sound actuated devices, and means actuated by the sound of traffic on the lane having the right-of-way for maintaining such right-of-way so long as such sound actuates the last said means.

4. A signal system for intersecting trafllc lanes having a right-of-way signal indication for sepa- .rate display to said lanes, means actuated by having a right-of-way signal indication for separate display to said lanes, means actuated by trafllc passing in said lanes to transfer right-ofway back and forth between said lanes, said means comprising sound actuated devices disposed in said lanes, and separate means actuated l0 3 by the sound of trafllc on the lane having the right-of-way for maintaining such right-of-way so long as such sound actuates the last said means.

6. A signal system for intersecting tramc lanes having a right-of-way signal indicationfor sepa- 1 rate display to said lanes, means actuated by traillc on one lane to display the right-of-way to that lane, means actuated by the sound of traffic on the lane having the right-of-way for mainthat lane, means actuated by the sound of tramc 40 on the lane having the right-of-way for maintaining such right-of-way so long as such sound actuates the last said means, and means-operated by trafllctin another lane operable to transfer right-of-way to that lane but subordinate to said last named sound actuated means.

CHARLES ADLER, JR.

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