US 3200218 A
Description (OCR text may contain errors)
Aug. 10, 1965 T. WAGNER SAFETY TRAFFIC SIGNAL LIGHTS 5 Sheets-Sheet 1 Filed Aug. 16, 1962 INVENTOR. TOBIAS WAGNER V. f M '0 ww 04 m Y Aug. 10, 1965 T. WAGNER 3,200,218
SAFETY TRAFFIC SIGNAL LIGHTS Filed Aug. 16, 1962 5 Sheets-Sheet 2 IN V EN TOR.
TQBIAES WAGNER Fry. 15'
Aug. 10, 1965 -r. WAGNER 3,200,218
SAFETY TRAFFIC SIGNAL LIGHTS Filed Aug. 16, 1962 5 Sheets-Sheet 3 DONT WALK RED RED GREEN INVENTORE TOBIAS WAGNER ATTOlP/ViV T. WAGNER Aug. 10, 1965 SAFETY TRAFFIC SIGNAL LIGHTS 5 Sheets-Sheet 4 Filed Aug. 16, 1962 POWER SUPPLY 245 INVENTOR. TOBIAS WAGNER Aug. 10, 1965 T. WAGNER 3,200,218
SAFETY TRAFFIC SIGNAL LIGHTS Filed Aug. 16, 1962 5 Sheets-Sheet 5 All I) II II III II II I II II IA QQy JNVENTOR.
TOBIAS WAGNER 2'2 United States Patent Filed Aug. 16, 1962, Ser. No. 217,356 Claims. (Cl. 260-922) This invention relates to trafiic light signals designed to indicate at all times the duration of time remaining before a signal cycle changes or terminates. Considerable difficulty is experienced by motorists in bringing their automobiles to a stop when a green light suddenly changes to red. Although in many jurisdictions an amber caution light is included, this does not represent a full solution to the problem, since the amber light remains on, usually, only for a very few seconds. Thus, the motorist may be approaching an intersection, maintaining a normal rate of speed suflicient in his judgment to permit him to pass the intersection while he still has a green light, and may be suddenly confronted with an imminent light change when he is almost at the intersection. Under these circumstances, it is necessary that he either bring his vehicle to a sharp stop or alternately, continue on through the intersection despite the fact that the signal may have completely changed before he is fully through the intersection.
It will be seen from the above that it is highly desirable that a motorist be provided with a visual indication, from the time the signal changes until the next change thereof, that will provide him with full knowledge as to the amount of time remaining before the next change. In this way, he can prepare himself further in advance, either for bringing his vehicle to a halt at an intersection, or alternatively, for preparing the vehicle to leave the intersection after it has been stopped thereat by a red light.
The difiiculty experienced by motorists is experienced also by pedestrians, who oftentimes, in endeavoring to cross an intersection at which controls exist in the form of traffic lights, find themselves stranded in the middle of the intersection, thereby incurring considerable risk of injury as traffic begins to flow in a different direction.
It has been heretofore proposed to provide a visual indication on a trafiic light signal whereby one can determine, generally, the extent of time remaining before the next light change. However, the main object of the present invention is to provide an improved type of device, which will be particularly adapted to provide a visual indication that can be seen at a substantial distance, so that an oncoming motorist can readily perceive the extent of time in a signal cycle remaining before he reaches an intersection and so that pedestrians can perceive the extent of time in the signal cycle remaining during which they can safely cross the intersection or during which they must wait before they can safely cross the intersection.
Another object is to provide a trafiic signal with cycled red and green lights with or without an accompanying amber light and having associated signal units divided into illuminated sections which progressively are extinguished during the timing cycles.
A further object is to provide a traffic signal wherein progressively extinguished illuminated sections provide walk and dont walk indications to pedestrians.
A further object is to provide novel switching means for turning the successive illuminated sections of the traffic signal on and oif.
For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings, and to the appended claims in which the various novel features of the invention are more particularly set forth.
In the accompanying drawings forming a material part of this disclosure;
FIGS. 1 and 1A are perspective views of traiiic signal devices embodying the invention.
FIG. 2 is a sectional view on an enlarged scale taken on line 22 of FIG. 1, with an associated switching circuit and power supply shown diagrammatically.
FIGS. 3, 4 and 5 are front elevational views of other trafiic signal devices according to the invention.
FIGS. 6 and 7 are diagrams of switching and power supply circuits of the signal devices of FIGS. 3 and 5, respectively.
FIG. 8 is a perspective view of a switching device which may be employed in the trafiic signal, certain components being shown schematically.
FIG. 9 is a vertical sectional view of another switching device, with certain components shown schematically.
FIG. 10 is an exploded perspective view of parts of the device of FIG. 9.
FIG. 11 is a vertical sectional view of another switching device.
FIG. 12 is a vertical sectional view taken on line 1212 of FIG. 11.
FIG. 13 is a side elevational view of another switching device, parts being shown schematically.
FIG. 14 is a side elevational View partially in section of another switching device.
FIG. 15 is a cross sectional view taken on line 15-15 of FIG. 14.
FIGS. 16, 17 and 18 are front elevational views of still other traffic signal devices.
Referring to the drawings, there is shown in FIGS. 1 and 2, a traflic signal device 10 in which five units 11-15 are stacked one above the other and secured in a housing 16. Unit 11 at the top of the assembly includes a front frame 18 in which are a plurality of rectangular openings 25 Behind each opening is a transparent clear or colored lens plate 22. Preferably colored red. A lamp socket 24 is mounted behind each plate 22 on floor plate 25 and carries an electric bulb 26. Each socket is connected via an electric cable 28 to a switching circuit and power supply 3% shown diagrammatically in FIG. 1. This circuit arrangement is explained below in connection with FIG. 6. A tapered rectangularly U-shaped hood 32 extends forwardly from frame 18.
Below unit 11 is unit 12 which has a front panel 34 provided with an opening 36. A transparent clear or colored lens plate 33 is located behind panel 34. Plate 38 i preferably colored red. A lamp socket 4G is mounted on floor plate 42 behind lens plate 38. The socket carries a lamp bulb 44 and is connected by cable 46 to the switching circuit and power supply 30. A curved hood 45 extends forwardly of panel 34.
Unit 13, which is below unit 12, has the same construction as unit 12 except that lens plate 38 is preferably colored yellow or amber.
Unit 14, which is below unit 13, has the same construction as unit 11 except that lens plates 22 are preferably colored green.
Unit 15, which is below unit 14, has the same construca tion as units 12 and 13 except that lens plate 38 is preferably colored green.
In signal device 1d of FIG. 1A, the same units are employed as in signal device it) except that units 12, 13 and 15 are disposed in a horizontal array. Unit 11 is placed on top of unit 12 and unit 14 is placed on top of unit is as in device lit. Other parts of the device 10' corresponding to those of device 10 are identically numbered.
In FIG. 3 is shown another trafiic signal device Id Three units 12 13 and 15* are mounted one below the other. The construction of these units is similar to units 12-, 13 and 15, respectively, except that hood 45 are shown as rectangular, although they could have other shapes. The lens plates 33, 38 and 38 of the several units are respectively colored red, amber and green. At one side of the three units is a unit 11? having a plurality of sections in' which are exposed lens plates 22' preferably colored red. The internal construction of unit ill is similar to thatalready described for unit ll, except that the unit fil may have a greater number of compartments containing the lamp bulbs. At the other side of units 12 13 and 15 is another multiple section unit 14 similar to unit 14 except that a greater number of compartments and lens plates 22" are provided and these lens plates are preferably colored green. The device titl employs a circuit as shown in detail in FIG. 6. In FIG. 4, trafiic signal device ltl is similar to device te except that unit 13 which contains an amber lens plate is omitted. The'laterally disposed units 11 and 14 are substantially identical with units it and M with red lens plates 22' in unit llll and green lens plates 22" in unit 14*. Also the same number of compartments are provided for the lamp bulbs in units 11 and 1 1 as are provided in units 11 and 1d. Device lh employs a circuit which is explained below in connection with FIG. 6. In FIG. is shown another traffic signal device lit This device has two units 11 and 11 Unit 13 includes a cabinet 5%) having front panels 52 provided with cutouts or apertures 54 spelling out the word DONT. Behind the panels are translucent or transparent lens plates 56 preferably colored red. A single lamp bulb 53 is located behind each of thefront panels. If desired, bulbs 5? can be colored red. Unit 11 has four compartments divided by horizontal floor plates or panels 69. It is to be understood that one or more lamp bulbs may be provided instead of the single bulb shown at 58. Attached to cabinet Sit by hinge 62 is a rear cabinet 64 which contains a switching circuit and power supply shown schematically in FIG. 7. 'Unit 11 is'similar to unit 11 except that two lamp bulbs 59* and 59* are located in each compartment. The lens plates 56* may be colored red, green or White but are preferably transparent, translucent or any color or uncolored while the lamp bulbs 59 and 59 are respectively colored red, green, white or any other color. In operation of the device, only the green bulbs 59* will light during one part of the operating cycle as will be explained in connection with the circuit of PEG. 7.
'During another part of the operating cycle as each one red bulb 58 in each compartment of unit ll lights up a companion red bulb 59 will light up in a compartment on the same horizontal level of unit 11 Thus, the device will display either WALK signs or red DONT WALK signs.
Circuit 3d shown in FIG. 6 is arranged for operation of device Til of FIG. 3; The circuit includes lamps 44,
' 4 5 and 44- which project red,'amber and green lights,
respectively, through the lenses of the compartments in which they are disposed. A first series of lamps 26 are designated 26A-26Fand are disposed in compartments of .unit 11*, A second series of lamps 26' designated 26G-ZdL are located in compartments of unit 14*. Each of the lamps has one terminal connected to common line 60 which terminates at one terminal 61 of a power supply 62. This power, supply may beanalternating or direct current source and may be connected to an external source of electric power or to a self-contained battery pack.
, A switching device 65 is provided for turningthe various lamps on and oh in a predetermined timed sequence This device includes tworotatable insulated or cycle.
ZtiA-ZdF and a power supply terminal 83. A stepped 1 switching plate 84; made of conductive material is secured and vice versa.
disks or plates 66, 68 mounted and rotated on a common insulated shaft 70 connected to. and driven by drive shaft '72 of a continuously driven motor 74; A first insulate (1' arm 76* is disposed radially 'adjacentrdisk 6d. This arm is'held stationary on a support 7%. The arm 76 carries a series of spaced brushes or wiper contacts fih dtl Each contacthas a lug hit to which is connected a wire 82 terminating at a different one of the red lamps to disk '66 and is contacted by brushes thi 8th as the disk 66 rotates.
Another stationary insulated arm 86 carries spaced brushes or wiper contacts 90 9tl Each contact hasa lug 92 to which is connecteda wire 93 terminating at a ditferent one or" green lamps 2dG-26L and at power supply terminal 83. Arm 86 is disposed-radially of disk 68. On the disk is a circular central switch plate 94 with a short circumferential segment 96 extending radially thereof. An arcuate stepped switching plate 98 isfdisposed.
radially of the centerplate 94 and makes electrical contact with segment 96 and plate 94 at point 99 where plate 93 is soldered or weldedto segment 96. V
Switching plate 84 has a series of six steps S which are spaced apart predetermined circumferential distances. The steps are uniformly radially spacedapart. Switching plate 9% has a series of six steps S which are spaced apart predetermined circumferential distances and are uniformly radially spaced apart. a p In operation of circuit 30 brush 36 makes continuous contact with plate 84 as disk 66 rotates. This connects terminal 83 continuously to the contact plate 84. Brush hil contacts plate 34 only during approximately 0t the'cycle of rotation of the disk. Brushes W -30 in turn contact plate 84 for approximately 30 shorter intervals. Brush 9%? contacts center plate continuously. as disk. 88 rotates. -Brush' 94% contacts segment 96 for a short intervalof a-few angular degrees. Brush 90 contacts plate 98 for an interval. slightly less than Brushes 9e -9tl contact plate 98 for successively shorter intervals, each about 30 or shorter than the next. While brush 90 contacts segment 96 no other brush contacts either of plates 34 or 9?. While brushes 9tl 9il arecontacting plate 98 none of. brushes 8tl 8tl contact plate 84 Due to the arrangement described it will be apparent that green lamp 44 will be lighted along with all of lamps 26. Then each of lamps 26G-26L will go out in succession and when lamp26L goesout, lamp 44 will also go out. Then only the amber lamp 44 will be lighted. When this lamp goes out, all the red lamps26 will go on along with red lamp 44-. Then each red lamp 26A-26F will go out in turn. When lamp 26F goes out, lamp 44 goes out also and a new cycle starts with the lighting of green lamp 44 and lamps 26.
The device 10 as viewed in FIG. 3, will show all the green lights in unit 13* and unit 1.5 coming on together.
The green lights 26 will go out one at a time from top to bottom, and when the viewer sees the last light on at the bottom of unit 14* he knows that the amber light td is about to come on. After the amber light goes out all the red lights in unit it? come on along with red light in unit 12 The red lights 26 go out one at a time from top to bottomjof the unit and when only the bottom red light remains the viewer knows that the green lights are about to come on and the red light 44 is about to go out, vice versa.
The circuit 3% can be used in the devices 10 and 10' of FIGS. 1, 1A, it six compartments are provided in each of units ll and 14. If only four compartments are provided in each of units lit and 14 as illustrated in FIGS. 1, 1A and 2, then contact plates 34 and 98'will be modified by omission of two. of each ot'steps S and S and spreading out circumterentially the remaining steps. V i The circuit 3W can be modified foruse in the device til of FIG. 4 by. omitting the segment 96 and the amber light 44 leaving only the red and green lights 44 and 44 in addition, two eachot steps S and S.will'be omitted from the plates 84- and hSand the remaining steps will be elongated circumferentially'so that the steps of each plate occupy about lSt). I 1
FIG. 7 shows circuit 3d? adapted for operatingthe pedestrian traflic signal 10 of FIG. 5. Each of lamps 58,
disk 100 rotates on insulated shaft 70' 59 and 59* has one terminal connected to the common line 60' terminating at terminal 61' of power supply 62. Terminal 83' is connected via wire 115 to the radially inner one of brushes 112 on stationary arm 110. Arm 110 extends radially of rotating insulation disk 100 carrying conductive switch plate 102. This plate has circumferentially spaced steps 106 and a circular portion 104. The driven by shaft 72 of motor 74'. Wires 114 are connected between the other brushes on arm 110 and the respective red lamps 58.
Terminal 83' is also connected via wire 125 to the radially inner of brushes 124 on stationary arm 122. The other brushes 124 are connected by wires 126 to green lamps 59*. Red lamps 59 are connected in parallel with red lamps 58. Disk 120 carries stepped contact plate 123 having four circumferentially spaced steps 130. When brushes 112 are on the outer stepped portions of plate 102, brushes 124 are off of the outer stepped portions of plate 128.
In operation of 30 and device all the red lights projected by lamps 53 and 59 through their lenses come on together to present red DONT WALK signs. Then the pairs of lamps 58, 59' go out in turn. When the lowermost red lamps 58, 59 go out, the green WALK lamps 59 all go on together. These lamps go out one by one as the several brushes 124 pass the several steps 130. When the last green lamp at the bottom of the device goes out, all the red DONT WALK lamps go on together to repeat the cycle. The last one or two green or red lights may be made to flash on and 011.
FIG. 8 shows diagrammatically a switching device which can be used in place of the switching devicesemploying stepped contact plates and brushes of circuits 30 and 30". Motor '74 drives a cam shaft carrying insulated cam plates or disks 152 spaced axially along the shaft. The cam plates have certain circularly edge portions 154 and other straight edge portions 156 chordal to the curved portions. The cam plates rotate between pairs of spring contacts 153, 160 supported by stationary bus bars 162, 164. The bus bars terminate at a power supply unit 62 Stationary contact elements or strips 166, 168 are supported on stationary conductive bases 170, 172 and are normally closed with or in contact with contacts 153, 160, respectively. Each of bases 170 is connected to a different lamp L which may be any one of a series of lamps shown in any of devices 10, 10 -10. Each of bases 172 is connected to a common line 175 connected to one terminal of each lamp.
As the cam shaft 150 rotates, each cam plate will separate a pair of spring contacts 158, 160 when the arcuate edge portions of the cam plate pushes the contacts outwardly to open the circuit normally closed through associated contact strips 166, 168. This opens the power supply circuit or" the lamp associated with the open contacts and the lamp goes out. The arcuate and fiat edges of the cam plates are arranged so that the lamps go out in turn as their power supply circuits are opened. This is the same function accomplished by the switching plates in circuits 350 and 30 FIGS. 9 and 10 illustrate another switching device which can be used in place of the switching devices employing stepped contact plates and brushes of circuits 30 and 30 The switching device 200 includes a frame 202 having a first pair of vertical rails 204 provided with opposing grooves 206 in which is slidable a first flat electrical contact plate 208. Plate 208 has a series of steps 210 formed in its upper edge. A lateral portion 212 of the plate carries an insulation strip 214 on which is a. rack gear 216 extending longitudinally of the plate.
Gear 216 is engaged by a spur gear 218 mounted on a shaft 220 and driven by a motor 74*. The motor is of reversing type. It is connected in circuit with power supply terminals 224 and a reversing switch 225 which may be a double-pole double-throw switch. The switch 7 has an operating arm 226 which is contacted by bottom edge of plate 208 at the lower end of travel of the plate so that the switch is thrown and the motor is reversed.
An insulation block 230 carrying spaced vertical contact elements or strips 232 is located so that the elements will contact plate 208 for different lengths of time as the plate moves vertically while being driven by gear 218.
Another contact plate 234 has steps 236 formed on its upper edge. Plate 234 faces plate 208 and carries an insulation strip 238 on which is another rack gear 240 facing rack gear 216. Rack gear 240 is also engaged by gear 216 which drives the plate 234 vertically in opposite directions to plate 203, so that when plate 208 is descending plate 234 is rising and vice versa. Plate 234 is guided in grooves 242 between two other rails 244 forming part of frame 202. Contact strips or elements 246. are vertically disposed to contact plate 234 for different periods of time as the plate moves vertically. Elements 246 are mounted on insulation block 250. Contact elements 232 and 246 have lugs 233, 245 which will be connected in circuit with the lamps, in place of the brushes of circuits 50 and 30* while the contact plates 208 and 234 will replace the contact elements carried by the rotating disks in those circuits.
It will be apparent from an inspection of FIGS. 9 and 10, that the left contact elements 232 and 246' will contact plates 2% and 240 for the shortest periods of time while motor 74 rotates at uniform speed. When plate 234 reaches the bottom of its travel between rails 244 it contacts operating arm 226 of the reversing switch and again reverses the motor. Thus, each time a plate 208 or 234 reaches the bottom of its travel it reverses the motor at the same time that the other plate reaches the upper end of its travel. In FIG. 9, plate 234 is just about to contact arm 226 to effect reversing of the direction of motor travel. When elements 232 are contacting plate 203 elements 246 are out of contact with plate 234 and vice versa.
The construction of the switching device 200 is preferred for some installations Where reciprocating rather than rotating contacts are desired.
FIGS. 11 and 12 show another switching device 200*, having another arrangement for reciprocating contact plates 203 and 234 provided with steps 218 The plates are movable in opposite directions in parallel grooves 250 ZSti formed in parallel insulated walls 252, 254. Each plate carries a horizontal insulated channel bar 256 256 A first crank pin 253 slidably engages in the channel of bar 256*". This pin is eccentrically carried by a spur gear 259 rotatably in a channel ring 260. Another pin 262 diametrically opposed to pin and extending oppositely from gear 259 and is slidably disposed in the channel of bar 256. A gear 264 on a shaft 265 is driven by a motor 266 rotates gear 259 and causes the plates 208 234 to slide in opposite directions. The steps of the plates alternately contact respective sets of contact elements 232 246 and the contact elements in each set respectively contact each contact plate for different lengths of time in a manner similar to that explained for the device 200. The contact elements will be connected to cincuits 30* or 30 in place of the switching devices therein employing stepped contact plates and brushes.
FIG. 13 shows another switching device 200 having another arrangement for reciprocating contact plates 208, 234" each provided with steps 210*. The plates move in parallel grooves formed between parallel walls, 270, 2723, 2'74. Insulated nuts 275 275 are secured to sides of the plates and receive threaded shafts 276 279. The shafts are journaled in bearings 280 280*, in an end wall 232 joining walls 270, 272, 274. The shafts have gears 286, 288 at their outer ends driven by a gear 290 on the end of a shaft 292 of motor 294. When the motor is running the threaded shafts are turned in opposite directions so that the plates 208 234 move in opposite directions. Thus the sets of contact elements 232 246 alternately contact the plates and the elements in each set contact the associated contact plate for a different length of time. The contact elements may be connected to circuits 3th or 36 in place of theswitching devices employed therein.
in grooves 509 wit formed in opposed insulated walls 362, 304 secured together by end walls 3%, 308. A shaft 309 passes through the parallel plates and engages a drive shaft 31%) which is connected by pin 312 to a crank or drive wheel 314. The wheel is rotated by a motor 316. The steps 210 and Zld of the respective contact plates extend in opposite directions and alternately contact the sets of contact elements 232, 2%". The elements in each set contact their associated contact plate for different lengths of time. The contact elements may be connected to the circuits 3th, or 36 in place of the switching devices employed therein. a
The invention may thus employ several different switching devices for automatically and cyclically turning oil? the green and red lights in a traffic signal for motorists and pedestrians. The traflic signal device may include time lapse signals in association with red and green signals with or without an amber warning signal; or the device may consist only of time lapse pedestrian signals. The several time lapse signals can be disposed in vertical arrays in a vertical assembly with the red and green lights with or without an amber light; or the time lapse signals can be disposed in vertical arrays alongside of vertical having a series of stepsat one end, means for reciprocab. ing the plates cyclically, two sets of contact elements, said sets being disposed to contact respective contact plates alternately, the contact elements in each set contacting a contact plate for a different length oftime as the plate is reciprocated by the reciprocating means, said reciprocating means including a motor, a circular drive means operatively driven by said motor, crank pins eccentrically carried by said drive means and disposed at diametrically opposed points, said pins engaging the plates respectively, and guide means for guiding the plates to move in different directions alternately as the drive means is driven by said motor.
, 3. In a traffic signal assembly having difierently colored lights, switching means for successively turning the lights on and off, comprising a pair of contact plates each having a series of steps at one end, means for reciprocating the plates cyclicallyptwo sets of contact elements, said sets being disposed to contact respective contact plates alternately, the contact elements in each set contacting a contact plate for different length of time as the plate is reciprocated by the reciprocating means, said reciprocating means including a motor, a drive gear operatively driven by said motor, crank ins eccentrically carried by said gear and disposed at diametrically opposed points, said pins engaging the plates respectively, and guide means for guiding the plates to move in different directions alternately as the drive gear is driven by said arrays of the red and green lights with or without an amber light.
The signallights can be disposed in horizontal or vertical arrays, or in any other formation. And the diiferently colored lights may be interchanged from the positions shown in the drawing.
All of the various modes of operation described above can be controlled remotely by means of well known radio control circuits. The remotely controlled devices can be made responsive to a fixed frequency or to a combination of frequencies or to coded signals. The traffic signals can be controlled by vehicle counter devices which register traific loads and can be set to vary the'timing of the trafiic signals in response to traffic loads.
In FIG. 16 two round lens plates are shown on one side and the corresponding parallel plates 22* are shown on the other side. In FIG. 17 three sets of similarly arranged plates 3tl and 2% are shown. In FIG. 18, the
, DONT WALK plates 3% are shown on one side and the corresponding parallel plates 22 on the other side.
While I have illustrated and described the preferred embodiments of my invention, it is to be understood that I do not limit myself to the precise construction herein disclosed and that various changes and modifications may be made within the scope of the invention as defined in the appended claims.'
Having thus described my invention, what I claim as new, and desire to secure by- United States Letters Patent is: v V
ll. In a trafiic signal assembly having difierently colored lights, switching means for successively turning the lights on and oil, comprising a pair of contact plates each having a series of steps at one end, means for reciprocating'the plates cyclically, two sets ofcontact elements, said sets being disposed to contact respective contact plates alternately, the contact elements in each set contacting a contact plate for a different length of time as the plate is reciprocated by the reciprocating means.
'2. In a trafiic signal assembly having dififerently colored lights, switching means for successively turning the lights on and off, comprising a pair of contact plates each In atrsfilc signal assembly having differently colored lights, switching means for successively turning the lights on and off, comprising a pair of contact plates each having 'a series of steps at one end, means for reciprocating the plates cyclically, two sets of contact elements,
said sets being disposed to contact respective contact plates alternately, the contactelements in each set contacting a contact plate for a different length of time as the plate is reciprocated by the reciprocating means, said reciprocating means including a motor, a drive gear operatively driven by said motor, threaded shafts operatively driven in different directions by said gear, nuts carried by said plates and engaged by said threaded shafts, and guide means for guiding the plates to move in different directions alternately as the drive gear is driven by the motor.
5. In a traflic signal assembly having differently colored lights, switching means for successively turning the lights on and olf, comprising a pair of contact plates each having a series of steps at one end, means for reciprocating the plates cyclically, two sets of contact elements, said sets being disposed to contact respective contact plates alternately, the contact elements in each set contacting a contact plate for a different length of time as the plate is reciprocated by the reciprocating means, said reciprocating means including a motor, a crank means operativeiy driven by the motor, a crankshaft connected to said crank means and reciprocated thereby, means connecting said crank shaft to said plates, and guide means for guiding the plates to reciprocate as the crank shaft is reciprocated.
References Cited by the Examiner UNITED STATES PATENTS NEIL C. READ, Primary Examiner. THOMAS E. I-IABECKER, Examiner.