US1880618A - Traffic signal system - Google Patents

Description

@CZC. 4, 15 232. c, WHETNEY 1,88%618 TRAFFIC S IGNAL SYSTEM Filed Nov. 19, 1928 Inverter Chaney F1 \Whitnag. O3

Patented Oct. 4, 1932 UNITED STATS PAENT OFFICE CHANCY r. WHITNEY, or SCOTIA, new YORK, ASSIGNOR ro GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK TRAFFIC SIGNAL SYSTEM Application filed November 19, 1928. Serial No. 820,247.

erated in response to sound produced on vehicles.

Means are now known whereby traflic signals which are utilized at the intersection of a main street and a side street may be adjusted normally to produce safe signals on the main street and danger signals on the side street and controlled in response to the sound'of the horn on a vehicle on the side street, the operator of which wishes to gain admission to the main street. In response to the sound of the horn the signals are operated through the usual cycle of operations including a safe signal to traflic on the side street and a danger signal to trailic on the main street and are then returned to the normal condition of safe on the main street and danger on the side street.

In systems of this kind it is necessary that means be provided whereby when the cycle of operations has once been started it cannot be interfered with by subsequent sounding of horns on the side street until the signals have returned to the normal condition and a safe signal on the main streetand a danger signal on the side street have been maintained for a predetermined period of time. It is also desirable that a signal be given to the vehicle operator who has sounded his horn during this predetermined period of time thereby to gain admission to the main street to inform him that the equipment has responded to the I sound of his horn and that the signals will change after this predetermined period'has terminated.

One of the objects of my invention is to provide means whereby these results may be accomplished which are of more simple construction and of more reliable operation than systems of known form, Another object of the invention is to provide means whereby the warning signal which is commonly used to indicate that a change in signals is about to occur may also be utilized as'an indication to the operator that the sound of his horn has been registered by the equipment and that the lights will change after a predetermined time interval.

Still another object of the invention is to provide means whereby the traflic signals may be operated not only in response to sound produced by vehicles on the side street but whereby the signals may also be operated by pedestrians who desire to cross the main street.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. y organization and method of operation, tonether with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawing in which the single figure represents an embodiment of my invention. 7

Referring to the drawing 1 and 2 represent respectively the'signal housings which are mounted upon the main and side streets in the usual manner. Each of these housings includes a danger signal R, a caution signal A, and a safe signal G, these letters being indicative of the colors red, amber and green which are commonly employed.

In accordance with the system to be disclosed these signals are controlled by means of a timing mechanism or controller 3 which is of well known construction, such as, for example, that shown in Patent N 0. 1,851,246, granted March 29, 1932 to Chester I. Hall, and this timing mechanism is in turn controlled responsively to sound produced upon vehicles upon the side street. The means invention itself, however, both as to its whereby this result is accomplished comprise 1y energized from an alternating current supply circuit 10 to which they are connected through conductors 11 and 12. The disk 8 serves'to drive the shaft 13 in a counterclockwise direction through a chain of gears 14. The shaft 13 carries a plurality of cams 15, 16, 17 18 and 19 which cams are arranged in spaced relation withrespect to each other and cooperate with levers 20 and 21 to control the position of a non-conducting member 22. This member 22 serves to operate contact fingers 23, 24, 25 and 26, which fingersin turn control the position of the signal lamps R, A and G. Each of these contact fingers cooperate with a stationary contact, all of which are connected together and to one side of the supply circuit 10 through conductors 27 and 28. v y

With the induction disk motor 8, 9 in the position shown in the drawing, it will be seen that contact finger 25 only is in engagement with its stationary contact. A circuit is completed which extends from one side of the supply circuit 10 through conductor 28, contact finger 25, conductor 29, lamps G on the main street and R on the side street, and conductor 30 to the opposite side of the supply circuit. Thus normally the lamp G provides asafe signal upon the main street and the lamp R a danger signal upon the side street. The motor 8, 9 is normally restrained in this position by means of a brake magnet 31. Brake magnet 31 has an armature 32 which swings about a. pivot 33 and which carries near its outer end a lever 34. The lever 34 swings about a pivot 35 and is arranged such that when the magnet 31 is energized, a projecting foot 36 on the lever 34 engages the disk 8 and the opposite end of the lever 34 falls within the path of travel of a stud 37 mounted upon a cam 38 which is carried by the shaft 13. Normally the stud 37 is in engagement with the lever 34 and bearing down thereon presses the foot 36 into engagement with disk 8 thereby restraining the disk and shaft 13 against rotation. This brake magnet 31 is energized through a circuit which extends from one side of the supply circuit 10 through conductor 11, actuating winding of the brake magnet 31, upper stationary contact and armature of relay 7 to theopposite side of the supply circuit 10. Relay 7 is normally connected across the supply circuit 10 through the armature and upper stationary contact of relay 6, which relay is included in the anode circuit of an electron discharge device 5.

The electron discharge device 5 is of the usual three-element type having a condenser and grid-leak. combination 39 connected in the grid circuit thereof, in series with the secondary winding of a microphone transformer 40. The primary winding of this transformer is included in circuit with a smoothing condenser 41 and the microphones 4. A

direct current potential is impressed upon supply circuit and the secondary 43 of which supplies potential through'a rectifying unit 45 to the condenser 41. This rectifying unit may be of any suitable form but preferably is comprised of rectifiers of the type shown in United States Patent No. 1,640,335 to Lewis 0. Grondahl issued August 23, 1927. The anode circuit of the electron discharge device 10 extends from the upper side of the supply circuit 10 through the space between the cathode and anode of electron discharge device 5, winding of relay 6, armature and upper contact of relay 6 to the opposite side of the supply circuit.

With the apparatus in the position shown in the drawing, let us assume that an operator, desiring to gain admission from the side street to the main street, sounds his horn. The microphones 4 operate and in a well known manner act upon the grid of the device 5 to diminish the current flowing in the anode circuit of that device. Relay 6 is deenergized and its armature is actuated into engagement with its lower contact thereby interrupting the anode circuit of device 5- and deenergizing relay 7. The armature of relay 7 is then actuated to its lower position thereby deenergizing the brake magnet 31, which in turn releases its armature and thereby permits themotor 8, 9 todrive the cam shaft 13 in a counterclockwise direction. "At the same time the armature of relay 7 completes an indicating circuit which extends from one side of the supply circuit 10 through the armature and lower contact of relay 7, conductor 46, signal lamp A in the housing 2 on the side street and conductor 30 to the opposite side of the supply circuit 10. The lighting of the signal lamp A indicates to the operator that his signal has been registered, and that after a predetermined interval of time the signals will change.

Upon rotation of the shaft 13through apre; determined are it will be seen that the lever 21 which rides upon cam 17 will drop down upon cam 19 and in so doing the member 22 carried by the lever 21 will be moved forward. This movement will be suflicient to,

at this time since this lamp is already lighted.

Upon further'rotation of the shaft 13 the lever 21 will drop from cam 19 on to cam 18 and'thereby move member 22 a second step forward. In this position contact finger 26 will be actuated into engagement with its Finger stationary contact and will thereby cause the energization of the danger lamp R on the main street and the safe lamp G on the side street. -At the same time this finger will again complete the anode circuit of discharge device 5 and energize relay 6. This circuit extends from one side of the supply circuit 10 through conductor 28, finger 26, lower stationary contact and armature of relay 6, act-uating winding of relay (3, anode and cathode of electron discharge device 5 to the other side'of the circuit 10. Relay 6 will now again be energized and will actuate its armature to the normal position thereby again energizing relay 7 which in turn actuates its armature to the normal position. In this position these relays are maintained energized through the armature and upper contact of relay 6. Brake magnet 31 is now again energized and actuates its armature 32 and lever 34 to the position shown in the drawing. However, since the stud 37 is not now in the position shown in the drawing the foot 36 of lever 34 will be held away from disk 8 by spring 50 and, hence, will not stop the rotation of the disk. lVith the controller in this position contact fingers 23 and 21 are both moved out from engagement with their sta tionary contacts, and, accordingly, the caution signals A on both the main and the side streets are extinguished.

The lever 20 which is now riding upon cam 16 will, after a further rotation of the shaft 16, drop down upon the portion 48 of cam 15. Upon this movement the upper end of lever 20 will engage lever 21 and thereby operate the member 22 into the position where caution signals were given. In this position fingers 23 and 24; are in engagement with their stationary contacts, and thereby energize the caution signals, while fingers 25 and 26 are both out from engagement with their stationary contacts. hen the period for caution signals has terminated the lever 20 will drop from the portion 48 of the cam 15 on to the portion 49 of that cam. and w ll thereby operate the member 22 back to the position shown in the drawing, thereby extinguishing the caution signals and again lighting the safe signals on the main street and the danger signals on the side street. After these signals have been maintained for apredetermined interval of time the stud 37 will again engage the end of shaft 34. Since the magnet 31 is now energized the lever 3 will fulcrum about the point 35. and thereby bring pressure upon the disk 8 sufficient to stop the motor. The signals will then be maintained in this position until the microphones et again respond to sound produced upon a vehicle.

It will be seen that after the motor 8, 9 has been released by deenergizing the brake magnet 31 in response to sound, the foregoing cycle of operations will ensue and that no of device 5.

interference can result from any subsequent sounding of horns upon the side street. During the cycle of operations the period of each of the different signals is determined entirely by the controller. the main street and the danger signal on the side street have been restored the controller is stopped by engagement of stud 37 with the lever 31 and these signals are maintained until subsequent actuation of the controller in response to sound produced on the side street. If, prior to this engagement one of the micro phones 1 is actuated, it will be seen that the caution light A on the side street will be lit'hted informing the vehicle operator that the sound of his horn has been registered. The magnet 31 will also be deenergized but the safe signal will be continued for the predetermined interval which is determined entirely by the controller. lVhen this interval is terminated. due to the fact that the magnet 31 is deenergized, the stud 37 will not engage the member 31, and, accordingly, another revolution of the shaft 13 will follow, thereby causing a subsequent cycle of operations.

To provide means whereby pedestrians upon the side street may obtain the right of way to cross the main street a key 51 is inserted in the microphone circuit. This key will preferably be mounted in convenient reach of the 1 edestrian at the street corner, and if desired one key may be provided at each corner and all arranged to interrupt or vary the current in the microphone circuit. hen the pedestrian opens the contacts of key 51 the current in the microphone circuitis interrupted thereby producing, through transformer 10, a voltage impulse upon the grid This impulse will cause the above cycle of operations to ensue.

lVhile have mentioned the use of my invention particularly in the operation of traftic signals at street intersections it will of course be understood that it has utility in other fields, as, for example. in railway signaling. Further. while I have described a particular cycle of operations. it will be understood that this cycle of operations, is dedetermin'ed entirely by the controller and may be varied as desired.

IVhile I have shown a particular embodiment of my invention, it will of course be understood that I do not wish to be limited thereto since many modifications. both in the circuit arrangement and in the instrumentalities employed, may be made without departing from the spirit and scope of my invention, as set forth in the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In a signal system for intersections of main and side streets, comprising a danger signal on the main street and safe and danger signals on the side street, a controller arranged for rotation, means tending to rotate lVhen the safe signal on Ill] ' troller and for interrupting said anode circuit, connections between said controller and said signals, whereby after said controller is released the signals on the side street are changed from danger to safe and then to danger, and said danger signal on the main street is operated simultaneously with the safe signal on the side street and means responsive to operation of the controller to a predetermined position for completing said anode circuit thereby to restore said relay and brake magnet to the normal condition.

2. In a signal system for main and side street intersections, comprising a danger signal on the main street and safe, danger and caution signals on the side street, a relay having normally closed and normally open contacts and an energizing circuit, means responsive to sound produced on the side street to interrupt said energizing circuit, a circuit for said caution signal including said normally open contacts, a controller arranged for rotation, means for restraining said controller in a predetermined position against rotation, said means including a magnet having a holding circuit including said normally closed contacts, whereby in response to said sound on said side street said caution signal is energized through said normally open contacts and said magnet is deenergized, connectlons between said controller and said signals whereby said caution, safe and danger signals are operated through a predetermined cycle of operations when said controller is released, and means responsive to operation of the controller to a predetermined position to complete said energizing circuit of said relay and thereby cause deenergization of said caution signal and energization of said magnet.

53. In a signal system for main and side street intersections, comprising a danger signal on the main street and safe and danger signals on the side street, an electron discharge device, a relay having a Winding and contacts included in said anode circuit, means including said electron discharge device whereby sound produced on the side street is caused to operate said relay thereby to interrupt said anode circuit, a controllerarranged for rotation, means for restraining said con troller in a predetermined position against rotation, said means including a magnet, a second relay, means to control said second relay in accordance with the operation of said first relay, said second relay having contacts ing said contacts whereby said controller is released upon operation of said second relay,

connections between said controller and said signals whereby when said controller is released said signals are operated through a cycle of operations, means including said first relay responsive to operation of said controller to a predetermined position for again completing said anode circuit whereby said first relay is energized and said second relay is operated to restore said magnet to the initial condition.

4. In a signal system for main and side street intersections, comprising a danger signal on the main street and safe, danger, and caution signals on the side street, an electron discharge device, a relay having a winding and contacts included in said anode circuit, means including said electron discharge device whereby sound produced on the side street is caused to operate said relay, thereby to interrupt said anode circuit, a controller arranged for rotation, means for restraining said controller in a predetermined position against rotation, said means including a magnet, a second relay, means comprising connections to control said second relay in accordance with the operation of said first relay, said second relay having contacts in circuit with said caution signal and said magnet, means comprising said contacts whereby said controller is released upon operation of said second relay, and said caution si nal is simul-- taneously energized, connections between said controller and said signals whereby when said controller is released said signals are operated through a predetermined cycle of operations, means including said first relay responsive to operation of said controller to a predetermined position for again completing said anode circuit whereby said first relay is energized and said second relay is operated to restore said magnet to the initial condition and said caution signal is deenergized.

In witness whereof I have hereunto set my hand this 17th day of November, 1928.

CHANGY F. WHITNEY.

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