US2131818A - Automatic traffic control system - Google Patents

Description

ct. 4, 1938. s, CQRQTH 2,131,818

AUTOMATIC TRAFFIC CONTROL SYSTEM I Filed Feb. 19, 1936 2 Sheets-Sheet 1 J7 JZ 6 BY myam l ATTORNEY-S s. c. ROTH AUTOMATIC TRAFFIC CONTROL SYSTEM Oct. 4, 1938.

Filed Feb. 19, 19:56 2 Speets-Sheet 2 ATTORNEYS Patented Dot. 4-, 1938 ATENT FFQ AUTOMATIC TRAFFIC CONTROL SYSTEM Samuel C. Roth, Allentown, Pa., assignor to Automatic Signal Corporation, East Conn a corporation of Delaware Norwalk,

Application February 19, 1936, Serial No. 64,771

" 1 Claim. 1 (01. 177-337) This invention relates to electrically operated traffic sgnal lights and has for an object to provide an automatic signaldevice of the stop and go,

or stop, caution, and go type capable of adjusting 5 itself to varying conditions of trafiic at all timesa A further object is to provide a device of this character adapted" to be installed at intersections where traffic is unequally divided and provide positive safety to vehicles desiring to cross the 1 main highway. v

A further object is top-rovide a device of, this character which will so control traffic that the traffic on the main highway will have uninterrupted right of way as long as no vehicles appear on the cross road to contestright of way.

A further object is to provide magnetically operated switches, responsive to cams, or contacts on the program control rotor, and a switch operated by Vehicles on the cross road, tooperate the traific signal on the main highway as an ordinary stop and go signal light as long as there are vehicles on the cross road to cross the intersection, and to maintain the trafiic signal continuous as a go signal for traffic on the main highway when no vehicles are on the cross road, thus preventing the unnecessary interruption of the main highway traffic by a stop signal when no traffic appears on the cross intersection.

With the above and other objects in View the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various-modifications may be resorted to within the 'scope of the appended claim without departing from the spirit or sacrificing any of the advantages of the invention.

In the accompanying drawings forming part of this specification,

Figure 1 is a diagrammatic view of trafiic signal apparatus constructed in accordance with the invention and showing the motor circuit open to maintain the green or go light continuously on' the main highway.

Figure 2 is a view similar to Figure 1 but showing the motor circuit closed to turn the rotor and the upper magnetically operated switch in open position thus to operate the device as a continuous stop and g signal of the conventional type.

Figure 3 is a view similar to Figure 2 but'showing the upper switch of the pair of magnetically operated switches in closed position to permit stopping of the program control rotor by cam 25 when one revolution of the rotor has been completed.

Figure 4 is a diagrammatic view showing how certain camsfon the program control rotor close associated switch contacts. 1 V

Figure 5 is a diagrammatic view showing how another cam on the program control rotor closes associated switch contacts. 5

Figure 6 is a diagrammatic view showing suggested arrangement of the signal apparatus" at an intersection of a main highway and a cross road.

Referring now to the drawings in which like characters of reference designate similar parts in the various views, 8 designates a traific signal of the type adapted to indicate a go or green signal 9 on the main highway simultaneously with a stop or red signal It) on the intersecting cross 1 5 road and vice versa. Vehicle operated switches H are disposed. on the cross road in the path of vehicles approaching the intersection'from either direction and these switches are shown as the type adapted to be closed by contact with a vehicle passing thereover although any preferred type of vehicle operated switch may be employed.

Assembled with the traflic signal 8 are a pair of opposed electro-magnets l2 and Hi and between the poles of the magnets there is mounted an armature M which is magnetically attracted by one or the other of the magnets to open and close a switch l5 which controls the motorcircuit of the trafiic signal. The switch l5 may be a single throw switch of the snap type adapted to be yieldably held at either limit of its movement, at one limit of its movement engaging a switch contact [6 in the motor circuit, shown best in Figure 2. l

When the vehicle operated switch H is closed by a vehicle passing thereov-er when approaching the intersection, a circuit H is closed through the magnet 53 which is thus energized to attract the armature l4 and close the switch It in the circuit E8 of the traffic signal motor IS. Themotor ro- .40 tates the program rotor 20 through a worm 2i and worm gear 22 to set in motion the program control cams 23.

The program control cams operate in the usual manner to close switch contacts 24 in the signal light circuits in sequence to first change the signal to caution or amber for the main highway. Then after an'interval the signal will be changedto go or green for the cross road and simultaneously to stop or red for the main highway. After another interval the signal will change to caution for the crossvroad and thereafter to stopor red for the-cross road and simultaneously to go or green for the main highway.

The latter or go signal for the main highway will remain continuous as long as no other vehicles appear on the cross road at the intersection and this is accomplished'by stopping the rotor at the end of one revolution by means of a cam 25 on the program control rotor. The cam is disposed to affect contact 26 preferably at the end of the predetermined go period for the main highway and closes switch contacts 26 in a circuit 21 which energizes the electro-magnet I2. When the magnet is energized it attracts the armature I4 to open the switch I5 which breaks the motor circuit, as shown in Figure 1. Thus the rotor will stop at a point which will give a cross lane vehicle a favorable light without delay.

It is essential that means be provided whereby a late arriving vehicle on the cross road will not be trapped at the intersection if the signal is about to change against it. For this purpose a pair of opposed electro- magnets 28 and 29 are assembled with the trafficsignal and between the poles of the magnets there is mounted an armature 30 which is magnetically attracted by one or the other of the magnets to open or close a switch 3! in the circuit 27. The magnet 28 is connected in series with the vehicle operated switch II and in parallel with the motor circuit closing magnet I3, as shown at 32. The magnet 29 is connected in circuit 33 with a pair of switch contacts 34 which latter are in the path of a cam 35 on the program control rotor 29. The cam 35 is disposed to affect contact 34 at or near the end of the go period for the cross road, or at the beginning of the caution period that follows, so that a late arriving vehicle will command the right of way regardless of its time of arrival, The magnet 28 should be more powerful than the magnet 29 in order to assure opening of the circuit 21 in the event that both magnets 28 and 29 are energized simultaneously.

When a late arriving vehicle that is, one arriving just as a change of signal is about to take place, passes over the vehicle operated switch II it will be seen that the circuit through the magnet 28 will be closed and the magnet thus energized attracts the armature 30 to open the switch 3| in the circuit 2! which controls the motor stopping electro-magnet I2. Consequently, when the advancing cam 25 closes the circuit 21 at the contacts 26 and magnet I2 cannot be energized to open the switch I 5 and stop the motor since its circuit 27 is open at the switch 3|, as shown in Figure 2. Thus the program control rotor must continue to another revolution during which time the late arriving vehicle may proceed safely across the intersection under the protection of the green or go, light of the cross road.

When the cam 35 subsequently closes the contacts 34 the magnet 29 will be energized to close the switch 3| which controls the circuit 21 so that in the event of no more trafiic appearing on the cross road, when the cam 25 next moves around into circuit closing position to close the circuit 21 at the contacts 26 the magnet I2 will be energized to open the switch I5 and break the motor circuit to stop the motor.

From the above it will be apparent that a vehicle on a cross road approaching a main highway intersection will always command a go signal and yet grant the traific on the main highway a sufiicient go interval to avoid unnecessary delay for traific on the main'highway.

From the above description it is thought that the construction and. operation of the invention will be fully understood without further explanation.

What is claimed is:

In a trafiic control system of the class described, a program control rotor, an electric motor for driving the rotor. a motor circuit which when closed energizesthe motor and when opened reenergizes the motor, a switch in the motor circuit, opposed electro-magnets one of which closes the switch and the other of which opens the switch, a vehicle operated switch connected in circuit with the switch closing electro-magnet, switch means operated by the rotor and controlling the electro-magnet which opens the motor circuit switch to normally confine the rotor to a single revolution; and means for permitting the rotor to continue through more than one revolution when the vehicle operated switch is actuated just as a change of signal is about to take place comprising a circuit, a switch in said circuit, opposed electro-magnets one of which closes the switch and the other of which opens the switch, the electro-magnet which opens the switch being connected in series with the vehicle operated switch and being connected in parallel with the electro-magnet which closes the motor circuit switch, switch contacts in said circuit, the other of the electromagnets being connected in series with the switch contacts, and a cam on the rotor for closing the switch contacts, coasting of the motor permitting the rotor to move sufliciently to disengage said cam from said switch contacts to deenergize said electromagnet which opens said switch.

SAMUEL C. ROTH.

, CERTIFICATE 0F CORREGTION. Patent No. 2,151,818. October h, 1958 SAMUEL c. ROTH,

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 2, for "sgnal" read signal; page 2, first column, line L 9, for "and magnet" read the magnet; same page, second column, line 26-27, for "re-energizes" read de-energizes; and that the said Letters Patent shouldbe read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this Zhth day of January, A, D. 1959..

Henry Van Arsdale (Seal) 7 Acting Commissioner'of Patents.

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