US1640170A - Street-traffic-signal device - Google Patents
Street-traffic-signal device Download PDFInfo
- Publication number
- US1640170A US1640170A US574493A US57449322A US1640170A US 1640170 A US1640170 A US 1640170A US 574493 A US574493 A US 574493A US 57449322 A US57449322 A US 57449322A US 1640170 A US1640170 A US 1640170A
- Authority
- US
- United States
- Prior art keywords
- lamps
- circuit
- lantern
- shield
- lamp
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08G—TRAFFIC CONTROL SYSTEMS
- G08G1/00—Traffic control systems for road vehicles
- G08G1/09—Arrangements for giving variable traffic instructions
- G08G1/095—Traffic lights
Definitions
- the invention subject of this application for Letters Patent is an improvement in street tratlc signaling systems such as are now being adopted and use both in cities and elsewhere for the control and regulation of vehicles at the intersections of streets and roadways.
- the control has been mainly, if not exclusively, manual, but my object has been to devise a system more nearly automatic in its operation and in which the indicating or warning signals may be controlled from more or less central points, not necessarily and purely automatically, but with provision for manual control ⁇ when conditions arise which make such control desirable or necessary.
- a primary object of the invention has been to provide for meeting such conditions of trailic as arise chiefly in the cities and larger towns in a simpler and less expensive manner than has heretofore been practiced, and at the same time to provide for exceptional conditions. For example, in the case of a tire or some catastrophe, should it become necessary to throw and set all signals to indicate danger and thus stop all tratc, this may be accomplished manually, without interfering with or impairing in any way the automatic control which at any moment may be resumed.
- each signal post or station three sources of light. These may be gas jets or electric lamps, and may be operated by either gas or electricity conveyed from any suitable source through pipes or conductors. rIhe description which follows will be conned to electric lighting systems, but at the present state of the art, those skilled in such matters will readily perceive, and, if re-v quired, will follow the steps that are necessary for the utilization ot' either one or the other.
- the system involves the use of either one or another of the three lamps employed with each signal post at any given time.
- two of the lamps are enclosed in a revolving translucent screen ot' different colors, and the third in a compartment at the top of the post having display openings, the lamp either having a distinctive color, or the o nings being provided with colored glass. his upper light is used in emergencies to stop all 1922.
- the signal post is provided with mechanism, controlled from a central station which determines the color or period during which the particular light is displayed, and this mechanism is operated by anovel arrangement of circuits and mechanisms which maybe more readily comprehended from the detailed description which follows, and in which references are made to the accompanying drawings.
- Fig. 1 is a view in central vertical section of a lantern mechanism which is intended to surmount a post or the like set at a proper point, as for example, the intersection of two streets,
- Fig. 2 is a .view mainly in elevation of portions of the interior mechanism and the colored translucent shield or screeny which surrounds the two main signal lights.
- Fig. 3 is a top plan view of the said interior mechanism, the lantern proper being shown in horizontal section.
- Figs. 4 and 5 are sectional views of the colored shields or screens, showing the arrangement of the colors, Fig. 4 showing the lower and Fig. 5 the upper half of the same.
- Fig. 6 is a diagram illustrating the electric circuitsv or wiring by means of which the signal lights are operated and controlled.
- Fig. 7 is a plan view of a form of cam used in connection with the circuits as a means of control.
- the lantern of Fig. 1 is supposed to be 'carried at the top of any suitable form of postor standard l, permanently or removably set at the intersection of two or more streets or roads.
- the casing for this lantern 2 may be cylindrical, or polygonal, of any proper material and character and mounted upon a base plate 3 mounted on the post 1.
- the lantern contains two stationary lamps 4 and 5, properly set upon or supported by a standard 6 in the center of the lantern case.
- a sleeve 7 carrying or formed with a bevel gear 8, upon which is mountd and secured a plate 9, supporting a cylindrical shield or screen of glass, or any other suitable translucent material 10 having sections or different colors.
- ⁇ In the side walls of the lantern are set eight lenses 11 which project the light from the lamps in four directions.
- the screen or shield 10 is designed to be revolved by intermittent steps or movements and for this purpose I secure a casting 12 in the bottom of the lantern which carries a bevel gear wheel 13 meshing with the gear 8. 'lio the spindle 14 of this gear 13 is fixed a ratchet wheel 15, which is engaged by a pawl 16 carried by a lever 17 concentrically mounted with reference to the ratchet wheel and operated by the core of a solenoid 18 to which said lever is connected by means of a link 19.
- the lantern Within the lantern are four symmetrically spaced segments or blocks 20 the inner faces of which are arc-shaped and closely approach the revolving shield 10 and which serve to divide the lantern chamber into four lightpassages which provide direct outlets for the light from the lamps through the colored sections of the said shield.
- a single conductor 21 extends from a central control station A to one or in series to any desired number of signal posts 1 to the ground at B.
- a battery 22 grounded at its centre 'at 23 and with its terminals connected to two switch plates 24 and 25. Between these plates is a central Contact plate 26 connected with the con ductor 21 and a switch lever 27 adapted to sweep over the contact plates, is connected with a contact stop 28.
- a cam plate 29 which is revolved at a predetermined and relatively slow rate of speed by clockwork or by a motor of some other character has projections 30 which operate a spring retracted circuit closer 31 connectedv with the line conductor 21 causing it at predetermined intervals to make contact with the stop 28.
- r1he line conductor 21 includes the coils of the solenoid 32 at each signal post and also the coils of a polarized circuit controlling magnet 33, the armature 34 of which vibrates between stops 35 and 36, and is connected by a wire 37 to one pole of any suitable supplemental source of electric energy.
- the stop 35 is connected through the lower lamp 4 with a circuit closer 38 operating in connection with a contact stop 39, connected to the other pole of the supplemental source, and also through the heating coils 40, surrounding an expansible metal bar 52, to the said other pole of that source.
- the stop 36 is connected to the upper lamp 5 of the pair and also to the colored lamp 41, which is contained in a compartment at the top of the lantern having four display openings 42 therein.
- the othcrterminal of this top lamp 41 is connected to a terminal 43 of a switch 44, while the lamp 5 is connected in the same way as lamp 4, to the terminal 45 of the switch lever 44.
- the colors of the screen and their circumferential divisions are largely arbitrary, but I prefer those indicated and described. That is to say, the lower half of shield 10 has two equal sections of green 46, facing each other and occupying together 2/8 of the circumference, and intermediate -red sections 47 occupying the remainder or 6/8 of the entire circumference.
- the upper half of the shield shown in Fig. 5 has two opposite sections of green 48 each occupying 1/8 of the circumference, two opposite sections of red 50 each occupying 1/8 of the circumference and intermediate sections of yellow 49 occupying together the remaining 4/8 of the circumference of the shield.
- the ratchet has 32 teeth, and four impulses pass through the solenoid, the result will be a movement of rotation of the colored shield or screen to the extent of one quarter of a complete revolution, and by spacing the teeth, the shield may be caused toexpose any given color for any given length of time during any one revolution.
- green may be brought into view for one street, hel for a moment and then changed to red, which persists in both directions until by the next two impulses green is shown at the side or 90 lenses and so on.
- the switch lever 27 is thrown onto contact 24 with the result that the current is reversed, which causes the polarized magnet to connect the lamp 5 with the circuit and throws out the lamp 4.
- the solenoid being neutral is not aii'ected by the direction of the current, but continues to revolve the shield 10 exposing, say, first a green then a red, and then a yellow light alternately up and down the intersecting streets.
- the switch lever 44 which is'conveniently located on or in the vicinity of a post, is turned from the stop 45 to the stop 43 by a traiiic oiiicer or other person with authoritydat the time when the polarized armature is in contact with the stop 36.
- This carries the current from the supplemental source through the lamp 41 which is maintained continuously in circuit, and cuts out of the circuit both lamps 4 and 5,.
- the mechanism for revolving the colored shields l0 is not interfered with, but as the lamps 4 and 5 are not lighted they produce no visible eiiect.
- the character and the manner oi use of the colors is not of the essence of the invention and may be varied to meet local or other conditions.
- the apparatus it is my intent-ion to use the lower light and the colors red and green during the day to control tratlic, and the upper light and the colors yellow, green and red during the night'.
- the arrangen'ient of the colors on the glass shield is such that in changing the right of way-that to say, green, from one street to another running at right angles, the color red is always displayed in four directions for a moment, with the object ot holding up all vehicular tratiic to permit pedestrians to cross.
- a similar arrangement causes the red to show after the green momentarily, until the full change is completed. This result is reached by the disposition of the projections on the cam disk at the central station.
- Fig. 7 has two sets ot projections which allow for two changes of lights in one direction it the shield be properly constructed, and colored. That is to say, the portion of the cam indicated at 53 may be assigned to the green, or right of Way, color, on a comparatively traiicless street, while the part 54 might be allotted to an important avenue, the traiic of which demanded a longer period. of right of way.
- the camprojections might be made movable or adjustable, so that any conditions of traflic on contiguous thoroughtares may be met.
- hA highway traiiic control system comprising, in combination, a signal lantern, two lamps in said signal lantern, a translucent revolving shield with differently colored sections surrounding each lamp, a pawl and ratchet mechanism for revolving said shield l step-by-step, an electromagnet for operating said pawl and ratchet mechanism, a circuit from a.
- central station including said electromagnet, means at the station for making and breaking said circuit at predetermined intervals, a second circuit adapted to include either one of said two lamps, and a polarized electromagnet in said firstmentioned circuit whereby either one of said two lamps may oe included in said second mentioned circuit.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Audible And Visible Signals (AREA)
Description
Au 3 1927. y
g *2 J. E. WRIGHT STREET TRAFFIC SIGNAL DEVTCE Filed July l2. 1922 2 Sheets-Sheet l wuemtoz lllllllllllllll l nml 9 141m@ v H il ENEL . 1,640,170 .1. E.V WRIGHT STREET TRAFFIC siGNAL DEVICE Aug. 23, 1927.
.Filed July l2. 1922 N 2 Sheets-Sheet 2 Patented Aug. 23, 19247.
UNITED STATES JOHN E. WRIGHT, or NEW YORK, N. Y., Yomr,
AssIGNon To AUSTEN H. Fox, or NEW N. Y. Y
STREET-TRAFFIC-SIGNAL DEVICE Application filed .'luly 12,
The invention subject of this application for Letters Patent is an improvement in street tratlc signaling systems such as are now being adopted and use both in cities and elsewhere for the control and regulation of vehicles at the intersections of streets and roadways. In these systems, as heretofore employed, the control has been mainly, if not exclusively, manual, but my object has been to devise a system more nearly automatic in its operation and in which the indicating or warning signals may be controlled from more or less central points, not necessarily and purely automatically, but with provision for manual control`when conditions arise which make such control desirable or necessary.
A primary object of the invention has been to provide for meeting such conditions of trailic as arise chiefly in the cities and larger towns in a simpler and less expensive manner than has heretofore been practiced, and at the same time to provide for exceptional conditions. For example, in the case of a tire or some catastrophe, should it become necessary to throw and set all signals to indicate danger and thus stop all tratc, this may be accomplished manually, without interfering with or impairing in any way the automatic control which at any moment may be resumed.
In carrying out the invention I have adopted foreach signal post or station three sources of light. These may be gas jets or electric lamps, and may be operated by either gas or electricity conveyed from any suitable source through pipes or conductors. rIhe description which follows will be conned to electric lighting systems, but at the present state of the art, those skilled in such matters will readily perceive, and, if re-v quired, will follow the steps that are necessary for the utilization ot' either one or the other.
In general terms, the system involves the use of either one or another of the three lamps employed with each signal post at any given time. For example, two of the lamps are enclosed ina revolving translucent screen ot' different colors, and the third in a compartment at the top of the post having display openings, the lamp either having a distinctive color, or the o nings being provided with colored glass. his upper light is used in emergencies to stop all 1922. Serial N'o. 574,493.
traffic, during which the two lower lights are -cut entirely out of circuit or action. Again the upper of the two lower lights .is used only at night, while the lower one only by day. The signal post is provided with mechanism, controlled from a central station which determines the color or period during which the particular light is displayed, and this mechanism is operated by anovel arrangement of circuits and mechanisms which maybe more readily comprehended from the detailed description which follows, and in which references are made to the accompanying drawings.
Fig. 1 is a view in central vertical section of a lantern mechanism which is intended to surmount a post or the like set at a proper point, as for example, the intersection of two streets,
Fig. 2 is a .view mainly in elevation of portions of the interior mechanism and the colored translucent shield or screeny which surrounds the two main signal lights.
Fig. 3 is a top plan view of the said interior mechanism, the lantern proper being shown in horizontal section.
Figs. 4 and 5 are sectional views of the colored shields or screens, showing the arrangement of the colors, Fig. 4 showing the lower and Fig. 5 the upper half of the same.
Fig. 6 is a diagram illustrating the electric circuitsv or wiring by means of which the signal lights are operated and controlled; and,
Fig. 7 is a plan view of a form of cam used in connection with the circuits as a means of control.
The lantern of Fig. 1 is supposed to be 'carried at the top of any suitable form of postor standard l, permanently or removably set at the intersection of two or more streets or roads. The casing for this lantern 2 may be cylindrical, or polygonal, of any proper material and character and mounted upon a base plate 3 mounted on the post 1. The lantern contains two stationary lamps 4 and 5, properly set upon or supported by a standard 6 in the center of the lantern case. Around this standard is a sleeve 7 carrying or formed with a bevel gear 8, upon which is mountd and secured a plate 9, supporting a cylindrical shield or screen of glass, or any other suitable translucent material 10 having sections or different colors. \In the side walls of the lantern are set eight lenses 11 which project the light from the lamps in four directions.
The screen or shield 10 is designed to be revolved by intermittent steps or movements and for this purpose I secure a casting 12 in the bottom of the lantern which carries a bevel gear wheel 13 meshing with the gear 8. 'lio the spindle 14 of this gear 13 is fixed a ratchet wheel 15, which is engaged by a pawl 16 carried by a lever 17 concentrically mounted with reference to the ratchet wheel and operated by the core of a solenoid 18 to which said lever is connected by means of a link 19.
Within the lantern are four symmetrically spaced segments or blocks 20 the inner faces of which are arc-shaped and closely approach the revolving shield 10 and which serve to divide the lantern chamber into four lightpassages which provide direct outlets for the light from the lamps through the colored sections of the said shield.
Assuming the signal lights,l as l have, to be produced electrically, a single conductor 21 extends from a central control station A to one or in series to any desired number of signal posts 1 to the ground at B. As a source of current ll have shown a battery 22 grounded at its centre 'at 23 and with its terminals connected to two switch plates 24 and 25. Between these plates is a central Contact plate 26 connected with the con ductor 21 and a switch lever 27 adapted to sweep over the contact plates, is connected with a contact stop 28. A cam plate 29 which is revolved at a predetermined and relatively slow rate of speed by clockwork or by a motor of some other character has projections 30 which operate a spring retracted circuit closer 31 connectedv with the line conductor 21 causing it at predetermined intervals to make contact with the stop 28.
The colors of the screen and their circumferential divisions are largely arbitrary, but I prefer those indicated and described. That is to say, the lower half of shield 10 has two equal sections of green 46, facing each other and occupying together 2/8 of the circumference, and intermediate -red sections 47 occupying the remainder or 6/8 of the entire circumference. On the other hand, the upper half of the shield shown in Fig. 5 has two opposite sections of green 48 each occupying 1/8 of the circumference, two opposite sections of red 50 each occupying 1/8 of the circumference and intermediate sections of yellow 49 occupying together the remaining 4/8 of the circumference of the shield. Under the conditions assumed, for day operation the switch lever 27 is turned to connect one pole of battery 22 by the contact, say, 25, with the stop 28, and the cam disk 29 permitted to rotate at a relatively slow speed in the direction of the arrow 51. Each projection 30 when it encounters the lever 31, closes the circuit from 25 through the conductor 21 and this operates the pawl 16 to move the ratchet the distance of', say, two teeth, and throws the polarized armature to a position in which it connects lower lamp 4 with the supply circuit. The lamp remains in this circuit until a second current is sent through thepolarized relay. 1f the ratchet has 32 teeth, and four impulses pass through the solenoid, the result will be a movement of rotation of the colored shield or screen to the extent of one quarter of a complete revolution, and by spacing the teeth, the shield may be caused toexpose any given color for any given length of time during any one revolution. Thus, green ma be brought into view for one street, hel for a moment and then changed to red, which persists in both directions until by the next two impulses green is shown at the side or 90 lenses and so on.
At night the switch lever 27 is thrown onto contact 24 with the result that the current is reversed, which causes the polarized magnet to connect the lamp 5 with the circuit and throws out the lamp 4. The solenoid being neutral is not aii'ected by the direction of the current, but continues to revolve the shield 10 exposing, say, first a green then a red, and then a yellow light alternately up and down the intersecting streets.
If the switch lever be shifted onto the central contact 26, no current will besent to the solenoids. If it be shifted so as to close contacts 24 or 25 and the center contact at the same time, the solenoids and the polarized magnets are continuously energized, and the functions of the cam cease altogether.
In case of emergency, as when a ireoecurs, which makes it necessary to block all traiiic, the switch lever 44 which is'conveniently located on or in the vicinity of a post, is turned from the stop 45 to the stop 43 by a traiiic oiiicer or other person with authoritydat the time when the polarized armature is in contact with the stop 36. This carries the current from the supplemental source through the lamp 41 which is maintained continuously in circuit, and cuts out of the circuit both lamps 4 and 5,. The mechanism for revolving the colored shields l0 is not interfered with, but as the lamps 4 and 5 are not lighted they produce no visible eiiect.
It is or may be desirable that all of the lamps, instead ot burning continuously, should flash, and for this purpose the circuit from the switch lever 44 is split, one path being through the bar 38 and stop 39 and the other through a high resistance path including a heating coil 40, surrounding an expansible metal bar 52, which normally holds the bar 88 out ot contact with the stop 39. lVhen current passes through coil 40 the'bar 52 expanded and closes this contact with the result that a path of low resistance is offered for the current which lights up the lamp. Thereupon the heating etl'cct ot' coil 40 is destroyed with the result that the contact is broken, to be again closed a moment later'. Any other and suitable form of vibratorI may be used for this purpose, that shown being merely typical of such means.
As above stated, the character and the manner oi use of the colors is not of the essence of the invention and may be varied to meet local or other conditions. As I have designed the apparatus it is my intent-ion to use the lower light and the colors red and green during the day to control tratlic, and the upper light and the colors yellow, green and red during the night'.
The arrangen'ient of the colors on the glass shield is such that in changing the right of way-that to say, green, from one street to another running at right angles, the color red is always displayed in four directions for a moment, with the object ot holding up all vehicular tratiic to permit pedestrians to cross. At night, when traiiic is light, a similar arrangement causes the red to show after the green momentarily, until the full change is completed. This result is reached by the disposition of the projections on the cam disk at the central station.
I have shown two forms of cams. That in Fig. 7 has two sets ot projections which allow for two changes of lights in one direction it the shield be properly constructed, and colored. That is to say, the portion of the cam indicated at 53 may be assigned to the green, or right of Way, color, on a comparatively traiicless street, while the part 54 might be allotted to an important avenue, the traiic of which demanded a longer period. of right of way. As a matter of fact, the camprojections might be made movable or adjustable, so that any conditions of traflic on contiguous thoroughtares may be met.
From the foregoing it will be seen that by the use of this system traffic-controlling lamps operated automatically, by means of a single control wire, may be placed at various points remote from a central station, and be made to display lights for the guidance of traiiic whether varying or of equal volume, on contiguous cross thoroughfares. The control at the central station, under ordinary circumstances is automatic, prearranged to meet known conditions, even though these vary. However, in case of eX- ceptional conditions or emergencies the control of the lights may be effected manually without impairment of the automatic operation when resumed. The system is therefore both elastic and effective.
In the practice of the invention it will be understood by those skilled in the art that certain precautions commonly recognized in all such systems should be taken. Among these may be mentioned the synchronizing, by well known means, of all of the lanterns and the use of means at the central station to shown these conditions at all times. Again, it will be understood that while the devices herein set forth are adapted for use with thoroughfares which cross at right angles, by properly constructing the lanterns streets running at any other angles may be similarly protected. These and other matters being well understood in the art, require no further or detailed description.
Having now described my invention what I claim as new and desire to secure by Letters Patent is:
1. In a system of highway traiiic control, the combination with a plurality of signal lanterns placed at the intersections ofstreets and roadways each containing two sets of lamps, one for use by day and the other by night, means in each lantern for displaying the lights of such lamps in different colors, a solenoid for operating said means whereby the color of the light displayed is changed, a polarized electro-magnetic switch for connecting with a source of current either the day or the night lamps, a controlling circuit from a central station including all the solenoids and all the polarized magnets of said switches and means in said circuit for sending over it currents 4in either direction for operating the light controlling means.CV
2. In a system of highway traffic control` the combination with each of a plurality of signal lanterns placed at desired positions, o
lamp, means for operating said shields for displaying dilerent colors, and means for switching in one or the other of said lights according to the conditions of traffic,
3. In a system of highway tra-flic control.` the combination with each of a plurality of signal lanterns placed at desired positions, of two lamps in each lantern arranged one above the other, a revolving translucent shield or screen having different color sections around each of the lamps, means for `revolving the shields electrically from a central station, and means for switching in one or the other of the said lamps according to the traflic conditions.
4. lin a system of highway traffic control, the combination with a signal lantern of three lamps one designed to display a single color, means for causing the other two to display different colors successively, means for switching into circuit either of the two lamps last mentioned, means for throwingl both out of action and the first-named lamp into circuit, a control circuit to the lantern from a central station, and means at said station for controlling such circuit.
5. ln ay system for highway traiiic control, the combination with each of a plurality of signal lanterns placed at desired points of a plurality of lamps, means or'causing some of said lamps to display diferent colors, and
means for causing one of them to display the same color, a controlling circuit from a central station for operating said first mentioned means, a neutral electromagnet there- 1n for operating said first mentioned means and a polarized magnet in said circuit for determining which of the said lampsfshall be brought into action. hA highway traiiic control system comprising, in combination, a signal lantern, two lamps in said signal lantern, a translucent revolving shield with differently colored sections surrounding each lamp, a pawl and ratchet mechanism for revolving said shield l step-by-step, an electromagnet for operating said pawl and ratchet mechanism, a circuit from a. central station including said electromagnet, means at the station for making and breaking said circuit at predetermined intervals, a second circuit adapted to include either one of said two lamps, and a polarized electromagnet in said firstmentioned circuit whereby either one of said two lamps may oe included in said second mentioned circuit.
ln testimony whereof l hereto aiix my signature.
JHN E. WRGHT.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US574493A US1640170A (en) | 1922-07-12 | 1922-07-12 | Street-traffic-signal device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US574493A US1640170A (en) | 1922-07-12 | 1922-07-12 | Street-traffic-signal device |
Publications (1)
Publication Number | Publication Date |
---|---|
US1640170A true US1640170A (en) | 1927-08-23 |
Family
ID=24296381
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US574493A Expired - Lifetime US1640170A (en) | 1922-07-12 | 1922-07-12 | Street-traffic-signal device |
Country Status (1)
Country | Link |
---|---|
US (1) | US1640170A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2457019A (en) * | 1945-08-20 | 1948-12-21 | Earl E Weber | Signal lamp |
US2524657A (en) * | 1945-12-20 | 1950-10-03 | Paul B Ford | Lighting device |
US4652851A (en) * | 1983-11-07 | 1987-03-24 | Ian Lewin | Lamp control system |
US5433166A (en) * | 1992-10-13 | 1995-07-18 | General Railway Signal Corporation | Railway light signal |
-
1922
- 1922-07-12 US US574493A patent/US1640170A/en not_active Expired - Lifetime
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2457019A (en) * | 1945-08-20 | 1948-12-21 | Earl E Weber | Signal lamp |
US2524657A (en) * | 1945-12-20 | 1950-10-03 | Paul B Ford | Lighting device |
US4652851A (en) * | 1983-11-07 | 1987-03-24 | Ian Lewin | Lamp control system |
US5433166A (en) * | 1992-10-13 | 1995-07-18 | General Railway Signal Corporation | Railway light signal |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2736002A (en) | oriel | |
US6175313B1 (en) | Attachment to traffic light apparatus for visual indication of traffic light duration | |
US6552668B1 (en) | Attachment to traffic light apparatus for visual indication of traffic light duration | |
US1640170A (en) | Street-traffic-signal device | |
US2480290A (en) | Luminous time lapse traffic signal | |
US2842627A (en) | Traffic time signal device | |
US2121179A (en) | Parking control apparatus | |
US1662348A (en) | Changeable sign and traffic signal | |
US2323793A (en) | Traffic signaling mechanism | |
US2526442A (en) | Combined clock and signal with time lapse indicator | |
US1756144A (en) | Traffic signal | |
US1973563A (en) | Highway traffic signal system | |
US2235728A (en) | Traffic signal | |
US1490567A (en) | Automatic traffic signal | |
US1251666A (en) | Municipal traffic-control system. | |
US1905378A (en) | Traffic regulating device | |
US1567871A (en) | Traffic-signaling system | |
US1818983A (en) | Signal timing device | |
US1954992A (en) | Traffic control system | |
US1625990A (en) | Traffic signal | |
US1863658A (en) | Switch mechanism for signal and other electrical circuits | |
US1536922A (en) | Traffic signal | |
US2435683A (en) | Traffic signaling system | |
US1575571A (en) | Traffic signal | |
US1328269A (en) | Signal system for controlling street traffic |