US2166721A - Traffic signal system - Google Patents

Description

July 18, 1939. w. M. JEFFERS TRAFFIC SIGNAL SYSTEM Filed July 1, 1937 OR. M

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Patented July 18, 1939 TRAFFIC SIGNAL SYSTEM Walter M. Jeflers, Syracuse, N. Y., asslgnor to Grouse-Hinds Company, Syracuse, N. Y., a corporation of New York Application July 1, 1937, Serial No. 151,478

2 Claims.

This invention relates in general to trafllc signal systems, and more particularly to such a system embodying means operable, in the event one of the lights in the signal becomes burned 5 out, to disconnect the signal from regular operation, and to display either a steady or a flashing caution signal. Frequently, the lamp or bulb in the green or red signal burns out, and when the lamp in the red signal burns out considerable confustion to traflic results until persons in charge of the signaling system have had an opportunity to replace the burned out bulb. This confusion results due to the fact that trafflc on one street receives a green or go signal, and the ll traflic on the other street receives no signal and often passes into the intersection, and this situation makes for collisions and serious accidents. This invention has as an object a particularly economical and simple arrangement whereby 20 upon one of the signal lights being burned out, a steady caution signal, or preferably a flashing caution signal, will be displayed to traffic.

In describing the invention, I make particular reference to the embodiment disclosed in the ac- 25 companying drawing which represents an across the line, schematic diagram of a signal system for one intersection embodying my invention.

However, at the close of the description it will be obviously apparent to those familiar with the 30 art that my invention may be also practised by making numerous changes in the wiring or hookup of the apparatus.

In the drawing, the signals MG, MR and MA designate respectively the green, red and amber 35 signals arranged to direct tramc on the main street of the intersection, and the signals CG, CR and CA designate the green, red and amber signals directing traiflc on the cross street.

On streets which pass through the intersec- 40 tion, the signals are displayed in both directions on the street, and it is conventional to employ a separate bulb or lamp for each direction. Accordingly, the signals above referred to on the drawing each employ two bulbs being grouped 45 together for simplicity in the drawing. These signals are successively and repeatedly displayed through regular trafllc cycles after the manner well hown to those familiar with the art. The successive and repeated display of the signals 50 may be accomplished by any suitable cycle timer mechanism.

As here shown, the shaft i is constantly rotated by motor H which includes driving coil 13 connected to the feed wire 14 and the com- 55 mon return wire l through wires 16, I1. A plurality of cams 18, I3, 26 and 2| are secured to the shaft I0 and rotatable therewith, and are arranged to actuate the movable members 22, 23, 24 and 25 of switches which include complemental stationary members 26, 21, 28 and 29. 5 The motor, cams and switches constitute a cycle timer for successively and repeatedly energizing the respective signal circuits.

The timer further includes a flashing switch comprising contacts 36, 3|, the movable contact 30 being operated by star wheel 32 secured to shaft Ill. The points of the star wheel 32 are arranged so as to actuate the movable element 30 at comparatively frequent intervals during rotation of the shaft Ill. The stationary mernher 3| is energized by wire l6.

The switch elements 22, 26 control the circuit energizing the main street green and cross street red signals. Each of the stationary members 26, 21, 28 and 29 are energized from the feed wire I4 by wire 35, movable contact 36, stationary contact 31, wire 38. When the movable member 22 is actuated into engagement with stationary member 26, a circuit is completed through wire 39, coil of relay 46, wire 4|, cross street red slgnal, wires 42, 43, to common return l5. A circuit is also completed through the main street green signal through wire 44 and common return wire 45.

Relay 46 is so designed or constructed as to 30 actuate its movable contact 46 by current flowing through both of the lamps in the cross street red signal. However, if either one of these lamps should burn out, the current flowing through the remaining lamp is not suflicient to cause movement of the armature 46, and permits it to move into engagement with stationary contact 41. The armature 46 is connected to the wire 39, and when the armature 46 is in engagement with contact 41, a circuit is completed through coil 49 of a thermal switch, the opposite leg of which is connected to the common return wire through wires 50, 5|, 43. When coil 49 is energized, movable member 54 of thermal switch is moved into engagement with contact 55 establishing a circuit through the coil of relay 56, through wires 35, 48, 51, contacts 54, 55, wire 56, relay 56, wire 43, to the common return. When relay 56 is energized, its armature 36 is moved out of engagement with stationary contact 31 thus breaking the feed circuit to the timer switches, and is moved into engagement with stationary contact 59. Inasmuch as armature 36 is energized from the feed circuit through wire 35, a stick circuit is established for relay 56, through wire 63, contacts SI, 62 of the manually operable switch or push button 3, wire 64. when armature 38 is moved into engagement with contact I9, aacircuit is also completed through the coil of relay 65, this circuit being established through wires 60, 68 and wires 69, 43, to the common return. The function oi relay 64 will be hereinafter explained.

A circuit parallel to that previously described is also established through the cross street green and main street red signals. This circuit is controlled by elements 23, 21 of the timer switch, and when these elements are moved into engagement by cam IS, a circuit is established through wires 10, H, through the coil of relay 12, wire 13, main street red signal, wire 45, to the common return. A circuit is also established through the cross street green signal by wire ll, wires 42, 43, to the common return. Armature 15, associated with relay I2, is connected to the wire Ill. The relay I2 is of similar design and construction as relay 40. That is, when either of the lamps in the main street red signal burn out, armature I5 is released or dropped into engagement with stationary contact 18. Accordingly, a hot feed is established through wire I! to coil 00 oi the second thermal switch, the opposite leg of the coil 00 being connected to the common return through wires SI, 43. When coil ill is energized, member 18 is moved into engagement with contact Bi, and a circuit is then established through relays 56, 64, as previously described.

Normally, the main street amber signal MA is energized by switch elements 25, 25, this circuit being established through wires 82, contact 83, armature 84, wire 85, through the main street amber light to the common return wire I! by wire 45. Also, in normal operation, the cross street amber signal CA is controlled by the switch elements, 18, the circuit being through wire 86, contact 81, armature 88, wire 89, through the cross street amber light, wires l2, 43, to the common return.

It will be observed, from the description thus far, that upon the failure of either lamp in the main street red signal, or cross street red signal,

relay becomes energized, causing the armatures 84, 83, associated therewith, to move out of engagement with contacts 83, 81, and into engagement with contacts 90, 9|. This eflfects deenergization of the two amber circuits, and inasmuch as the contacts 90, ii are connected with the movable element 30 of the flasher switch through wires 92,13, the amber signals are shifted from the control of cams 20, 2i, and displayed in flashing sequence by the operation of star wheel 32 and switch elements 30, 3|. This condition will maintain until the burned out light or lights are replaced, and the manually operable switch 63 is opened.

The purpose or the manual switch or push button 33 is to release the stick circuit of relay 5.. That is, after the attendant has replaced the burned out bulb, the switch 63 is momentarily opened to deenergize the relay 56 and permit armature 38 to drop into engagement with contact 31.

The purpose or the thermal switches 54, 16 is to permit relay 40 to move armature 48 out of engagement with contact 41 without energizing relays II, I when the switches controlled by cams l8, I! are initially closed. That is, due to the fact that armatures It, I! are energized by wires 39, I0, relay 58 might be energized sufllciently to actuate the armature 36 and close the stick circuit for relay 5 and energize relay 65. The thermal switches 54, 1B are so designed and adjusted as to close into engagement with contacts 55, 3| four or flve seconds after their re spective coils 48, I0 have been energized.

What I claim is:

l. A trafllc signaling system including a plurality of signal circuits, each of said circuits including a signal light and a switch, a timer operable to successively and repeatedly actuate said switches, a flasher switch, a feed circuit for said flasher switch, a feed circuit common to said first mentioned switches including means normally connecting said feed circuit to said switches and operable to disconnect the ieed circuit from said switches, certain of said signal circuits including means normally connecting the same to oertain or said first mentioned switches, and being operable to disconnect said caution signal circuits from said first mentioned switches and to connect the same to said flasher switch, certain other 0! said signal circuits including means operable, upon failure of the signal light in said other circuit, to eflfect operation of said means in said ieed circuit, and to effect operation of said means in said first mentioned signal circuit.

2. A traillc signal system including a go signal circuit, a stop signal circuit, and a caution signal circuit, each of said signal circuits including an electric light illuminated when said circuit is energized, a timer including a switch connected in each or said signal circuits, a feed circuit common to all of the switches of said timer,

and said timer and switches being operable to successively energize said signal circuits, said stop signal circuit including means operable, upon failure of the light in said circuit, to eilect deenergization of said i'eed circuit to the timer switches and to energize said caution signal circuit.

WALTER M. JEFFERS.

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