U.S. patent number 3,895,345 [Application Number 05/384,810] was granted by the patent office on 1975-07-15 for traffic signal apparatus.
This patent grant is currently assigned to Belmar Electronics Corporation. Invention is credited to Carl L. Elvers, Ralph A. Elvers.
United States Patent |
3,895,345 |
Elvers , et al. |
July 15, 1975 |
Traffic signal apparatus
Abstract
A traffic signal for controlling vehicular traffic and typically
having red, yellow and green signal lights therein, is provided
with an additional signal light, in the form of a circular type
strobe light, which is centrally disposed in front of one or more
of the signal lights. Electronic control circuitry is provided for
initiating operation of the strobe light when the signal light
associated therewith is illuminated including when the lamp in the
associated signal light fails to function.
Inventors: |
Elvers; Carl L. (Indianapolis,
IN), Elvers; Ralph A. (Indianapolis, IN) |
Assignee: |
Belmar Electronics Corporation
(Tampa, FL)
|
Family
ID: |
23518849 |
Appl.
No.: |
05/384,810 |
Filed: |
August 2, 1973 |
Current U.S.
Class: |
340/907;
340/331 |
Current CPC
Class: |
G08G
1/095 (20130101); G08G 1/097 (20130101) |
Current International
Class: |
G08G
1/097 (20060101); G08G 1/095 (20060101); G08g
001/07 () |
Field of
Search: |
;340/41,42,43,105,103,44 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Habecker; Thomas B.
Attorney, Agent or Firm: Trask, Jenkins & Hanley
Claims
We claim:
1. An apparatus for controlling vehicular traffic, which comprises
a signal light housing, a signal light having a reflector, a
signalling bulb and a lens mounted in said signal light housing,
said signalling bulb being interposed between said reflector and
said lens, a strobe light housing secured to said signal light
housing, a strobe light mounted in said strobe light housing and
disposed on the viewing side of said lens, timing means for
energizing said signalling bulb, and electronic control circuit
means operable by said timing means for operably pulsing said
strobe light off and on at a preselected rate when said signalling
bulb is energized, said strobe light being generally circular in
shape and suspended by a plurality of filaments in a substantially
concentric position with respect to the light emitted by said
signalling bulb and reflected by said reflector.
2. The apparatus as claimed in claim 1 wherein said filaments for
supporting said strobe light are comprised of a light transmitting
material.
Description
BACKGROUND OF THE INVENTION
This invention relates to a traffic signal of the variety having
red, yellow and green signal lamps mounted therein for controlling
vehicular traffic on streets and highways.
Conventionally, vehicular traffic is controlled through the use of
traffic signals having a red signal light for stopping traffic, an
amber light for indicating a caution condition and a green signal
light for allowing traffic to proceed. Of these lights, the
observance of the red signal is perhaps the more important, as it
is imperative for safe highway conditions that the red signal and
its indicated action be observed. The red light, however, has
several disadvantages which make its use in urban areas less than
satisfactory.
More specifically, it is known that everyone, due to the
physiological construction of the human eye, is color blind to the
color red when the eye is directed in a normal straight ahead
viewing line, and the color red is presented to the eye from an
angle of greater than about 20.degree. with respect to the straight
ahead viewing line. Therefore, if the attention of a driver of a
vehicle is diverted as he approaches an intersection having a
traffic signal, there is the distinct possibility that the red
signal light will not been seen at the required time or will go
completely unnoticed due to the driver's angle of attention.
Secondly, some cities are now using high energy street lights, such
as of the Lumilux variety, which yield an orange glow over the
lighted area and which tend to negate the red color of a traffic
signal when it is viewed in the shaded environment created by such
street light. Large numbers of illuminated and brightly colored
advertising signs, which are common at, or in the vicinity of, high
traffic density intersections, have also beeen found to distract
from and even totally negate the effect of a red light and cause
its warning to go unheeded.
It is, therefore, particularly desirable to provide a traffic
signal wherein the red signal light in that signal has reinforcing
means to indicate that a red signal is illuminated and which can be
detected at virtually all angles of observation; which is effective
in an environment utilizing street lights casting a colored glow
over the environment; which can be used to negate the effects of
illuminated and brightly colored advertising signs located at
proximate locations to the intersection controlled by the traffic
signal; and which is, if desired, capable of being added to an
existing traffic signal.
SUMMARY OF THE INVENTION
In accordance with the invention, a traffic signal is provided
wherein at least the red signal portion of the overall device is
provided with a brilliantly flashing strobe light positioned on the
viewing side thereof and preferably centrally disposed within the
viewing area of the red signal portion. The portion of the overall
device containing the strobe light can be factory installed during
the construction of the overall device, or, in the alternative, can
be installed in an auxillary red signal light housing mounted atop
or proximately to an existing traffic signal device to accentuate
and draw attention to the red or other signals therein.
A flashing or pulsating of the strobe light can be effected by
electronic circuitry concurrently with the illumination of the red
signal light, even if the lamp in the red signal is inoperative.
The electronic control circuitry for the pulsating strobe light can
be controlled by the standard timing mechanism associated with the
traffic signal to initiate operation of the strobe each time the
red or other signal light with which it is associated is
illuminated.
The brilliantly flashing strobe light has been found to provide
somewhat of an irritant to the human eye so that when the red light
is illuminated, and the strobe light is pulsating or flashing,
attention of vehicle operators are drawn to focus on the red light
which appears to surround the centrally disposed strobe light. The
light emitted by the strobe has also been found capable of being
peripherally detected up to an angle of 95.degree. taken with
respect to a straight ahead viewing line, and, thereby compensates
for the color blindness to the color red which is incurred when the
red light is peripherally viewed at an angle of greater than about
20.degree. with respect to the same straight ahead viewing
line.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate the invention and, by way of
example, show a preferred embodiment. In such drawings:
FIG. 1 is a front view, taken in perspective, of a conventional
three light traffic signal;
FIG. 2 is a perspective view, in exploded form, showing a signal
light embodying the invention;
FIG. 3 is a front view of the strobe housing of FIG. 2 showing a
strobe light mounted therein;
FIG. 3a is a front view of the strobe housing showing an alternate
configuration of strobe light and mounting; and
FIG. 4 is an electronic circuit diagram of a circuit for
operatively controlling a signal light and a strobe light.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The traffic signal shown in the accompanying drawings is for the
effective and safe control of vehicular traffic, especially in an
intersection with a high number of intersecting highways, or where
such area is environmentally illuminated at night with Lumilux
lighting, or in an area having a high concentration of illuminated
or brightly colored advertising signs immediately adjacent the
intersection. The high intensity Lumilux type street lighting has
been used in urban areas to reduce the possibility of crime
incidence in such areas which would be encouraged and aided by poor
lighting. Although such lighting does provide a more adequate
illumination of the surrounding environment, a somewhat detrimental
effect of it is to cast an amber or orangish glow. These amber
tones have been found to cancel out the red of traffic signals in
the proximate area thereto, thereby causing such signals to go
unnoticed.
The present invention can be incorporated into a standard three-way
traffic signal housing which is illustrated in FIG. 1. The signal
10 is comprised of three sub-parts 12, 14, and 16 which are
integrated by a singular housing 18. Typically, the top sub-part 12
contains a red lens 20, the middle sub-part 14 an amber lens 22,
and the bottom sub-part 16 a green lens 24. Access doors 26, 28 and
30 on the respective sub-parts 12, 14 and 16 of the signal 10
provide access to the respective signal lamps (not shown in FIG. 1)
and the various electrical apparatus therefor. These access doors
26, 28 and 30 can be swung open on individual hinges 32 for repair
and maintenance of the enclosed apparatus, and are held in their
closed position by single turn fasteners (not shown).
The assembly and apparatus showing the inclusion of the inventive
assembly is best seen in FIG. 2, wherein one of the sub-part signal
units 12, 14 and 16 is shown. It should be understood that the
inventive assembly can be incorporated into any one or all of the
aforementioned sub-part units 12, 14 and 16. However, it has been
found preferable to include the inventive assembly in the red
signal sub-unit 12 to overcome the above discussed inherent
problems associated with the use of red signals for traffic
control.
For the purpose of facilitating the description, only the apparatus
used in the top signal unit 12, i.e., the red signal, of the three
sub-part signal 10 shown in FIG. 1 will be described with reference
to FIG. 2. The primary signalling device within the signal unit 12
is a conventional signalling bulb 42. The bulb 42 is enclosed by a
hyperbolic reflector 44 which surrounds the signalling bulb 42 to
increase the intensity of and direct the light from the signalling
bulb 42 through the red lens 20 toward the front of the signal unit
12. A retaining flange 46 is provided around the forward perimeter
of the hyperbolic reflector 44 for mounting the red lens 20. The
lens 20 is retained in the reflector flange 46 by retaining spring
clips 48.
The rearward end 50 of the hyperbolic reflector 44 is securely
fitted, as by screw threads, into the face of a light socket 52
which also receives conventional screw threads 54 on the signal
lamp 42. The signal lamp 42 is screwed into the socket 52 and, by
means of electrical conductors 56 and 58 leading to the socket,
receives the energizing voltage at the appropriate time.
The hyperbolic reflector 44, the lamp 42 and the socket 52
therefor, form a unitary assembly which is mounted in a supporting
and swingable ring member 60 which has a circumferential groove 62
in the forward face thereof into which a mating edge or flange 64,
formed in the outer and rearwardly extending periphery of the
reflector 44, snugly fits. Epoxy resin or the like can be used to
further secure the reflector edge 64 in the supporting groove 62.
The supporting ring 60 has an upright portion 66 formed on one side
thereof. The upper and lower ends of this upright member 66 are
reduced in diameter to form mounting pins 68 which are swingably
received in mounting brackets 70 which are secured to the internal
sides of the top and bottom of the unit housing 12. In this manner,
the entire light and reflector assembly can be swung outwardly to
provide access to the internally located electronic control
circuitry for the device.
The above described apparatus is enclosed in the housing 12 and
sealed therein by the front door 26 of the unit which itself is
comprised of a door portion 72 having a circular hole 74
therethrough and which is surrounded by a mounting flange 76. The
door portion 72 has two projections 78 extending from one side
thereof and each of which have a pin 80 protruding therefrom. The
pins 80 are swingably received in supporting flanges 82 to form and
comprise the hinges 32. A sealing gasket 84 is provided around the
outer face 86 of the housing 12 to provide a tight seal against
such face 86 when the front door 26 is held in its closed position
by a single turn threaded fastener 88 which acts against a
bifurcated locking member 90 formed as an integral part of the door
26 on the side opposite to that of the supporting pins 80.
A strobe housing 92 is mounted on the mounting flange 76 on the
front of the door 26. This housing 92 contains and supports a
circular strobe light 94 and a clear lens 96. A gasket 98 is
interposed between the rim 100 of the clear lens 96 and the
interior side of a radial flange 102 formed and radially extending
from the periphery of the front of the strobe housing 92. The lens
96 and gasket 98 are held in place against this flange 102 by
appropriate means such as clips 104. The strobe light housing 92 is
fastened tightly to the exterior side of the door flange 76 to
provide a weather proof encasement for the strobe light 94.
As best seen in FIG. 3, the strobe light 94 is centrally suspended
within the strobe housing 92 by three Teflon filaments 106 which
can be wrapped around the strobe 94 in the appropriate arcuate
position or, can be attached to Teflon collars 108 for connecting
the strands 106 to the strobe light 94. The outer ends of the
filaments 106 are securedly fastened in holes 110 formed in the
strobe housing 92. The Teflon filaments 106 provide adequate
support for the strobe light 94, yet do not interrupt the rays of
the red signal light which must pass therethrough.
The Teflon filaments 106 can be replaced with appropriate thin
wires which can be interrupted by springs for providing a shock
absorbing quality to the strobe light supports to prevent
unnecessary shock to the strobe light 94 during high winds which
would jolt the overall signal light 10.
Energizing voltage for the gas, desirably Xenon, in the strobe
light 94 is applied by input conductors 112 and 114 leading to the
light 94. The strobe light will only be illuminated when a grid
wire 116, which is wound externally around the light 94, is
triggered or energized by means of an energizing conductor 118
which is electrically connected to the grid wire 116. The three
electrical conductors 112, 114 and 118 for the strobe light 94
extend generally axially outward from the strobe light into the
sub-unit housing 12 where they are conveniently secured to a
terminal block 120 along with the two conductors 56 and 58 from the
primary signal lamp socket 52. Electrical connections can then be
made from a control circuit board 122 to the terminal block 120 for
providing energizing voltage for the main signal lamp 42 and the
requisite pulsating signal voltage for the strobe 94 at the
appropriate times.
An alternative embodiment of the strobe light and mounting therefor
is illustrated in FIG. 3a. In this instance, the strobe light 95 is
linear and is mounted in shock absorbing sockets 97 and 99 which
are secured to the interior side of the housing 92. The electrical
conductors 112, 114 and 118 can extend into the sub-unit housing 12
to be secured to the electrical terminal block 120. The strobe
light in this embodiment presents a brilliantly flashing line
within the observed red light, where the embodiment of FIG. 3
presents a circular light centrally emanating from the observed red
light.
The control circuitry 124 for operating the strobe light 94 is
mounted on the control circuit board 122 and is shown in detail in
FIG. 4. An alternating current supply voltage is impressed across
two input conductors 128 and 130 from a conventional AC power
supply (not shown). One of these input conductors 128 is connected
to one side of a normally open timed switch 132 which is integral
with and forms part of a switching mechanism (not shown) as is
conventionally used to operate a traffic signal light. The normally
open switch 132 is opened and closed in accordance with a typical
manner to change from a red signal, to an amber signal then to a
green signal, etc. The input conductors 56 and 58 for the signal
light socket 52 are connected between the switch 132 and the other
side 130 of the input voltage supply. The remaining portion of the
circuitry shown in FIG. 4 is for the control and operation of the
strobe light 94.
In general, the strobe light 94 must be supplied with a triggering
pulse and a relatively large direct current voltage each time the
strobe light is to be illuminated. Alternating current at line
voltage is supplied to a pair of diode clamping circuits 134 and
136 when the timed switch 132 is closed. These clamping circuits
134 and 136, which are each comprised of a diode 138 and a
capacitor 140 effect a shift in the incoming alternating current
wave form so that the wave form has no negative excursions. Two
peak rectifiers 142 and 144 are coupled to the diode clamping
circuits 134 and 136, respectively, to rectify the now positive
wave form, which, in effect, provides a D.C. voltage across a
capacitor 146 and 148 in each of the peak rectifiers 142 and 144.
This D.C. voltage is equal to twice the amplitude of the line
voltage which is impressed across the input conductors 128 and
130.
The output from the peak rectifiers 142 and 144 is taken from the
positive side 150 of the capacitor 146 in the first rectifier 142,
and from the negative side 152 of the capacitor 148 in the second
rectifier 144. It should be seen and understood that the voltage
measured across these conductors 150 and 152 is equal to four times
the amplitude of the alternating current input voltage.
The positive output conductor 150 is connected to the positive
terminal input conductor 112 of the strobe light 94. The second, or
negative output conductor 152 is similarly connected to the
negative input conductor 114 of the strobe light 94. The voltage
thereby impressed across the strobe light 94 is present whenever
the timing switch 132 is closed. However, the pulsating
illumination of the strobe light 94 must be initiated by the
application of a triggering pulse to the triggering conductor
118.
The triggering pulses are supplied by an SCR triggering circuit
154. The anode 156 of an SCR 158 in this circuit is coupled to the
positive D.C. conductor 150 by a coupling resistor 160, while the
cathode 162 of the SCR 158 is connected directly to the negative
D.C. conductor 152. The SCR, which is normally in a non-conductive
state, is turned on by the application of a sufficient level of
voltage to its gate electrode 164 through a diac 166. A resistor
168 and a charging capacitor 170 determine the firing rate for the
SCR according to their combined R.C. time constant. Charging
voltage is supplied to the R.C. network through a coupling resistor
172 which is connected to the anode 156 of the SCR. When the
capacitor 170 has charged to a sufficient voltage level, such
voltage being available at the gate electrode 164 of the SCR 158,
the SCR is rendered conductive and provides a short circuit from
the negative potential line 152 to a capacitor 176 which is coupled
between the SCR anode 156 and one side of the primary winding 178
of a transformer 180. The other side of the primary winding 178 is
connected to the negative potential line 152. The conductive state
of the SCR 158 rapidly discharges the capacitor 176 and collapses
the voltage impressed across the primary winding 178 of the
transformer 180. This rapid change of voltage in the primary
winding 178 induces a large pulse of current in the secondary
winding 182 of the transformer 180. This pulse is thereby
communicated to the triggering conductor 118 of the strobe light
94, as the conductor 118 is connected to one side of the
transformer secondary winding 182.
The triggering pulses are very short in duration, e.g., on the
order of one thousandth of a second. It has been found more
desirable for traffic control to effect a triggering frequency of
approximately 60 times a minute. The resulting short duration, 1
hertz triggering of the strobe light 94 creates a high intensity
flashing of the strobe, on the order of one million candle power,
which, when disposed in front of the red signal light 42, has been
found to provide a highly effective and safe traffic controlling
apparatus. It is believed that the flashing of the strobe, which
from a distance is viewed as emanating from the center of the red
signal light or, in the alternative, as a line across the signal
light, draws the attention of the drivers of approaching vehicles
to focus upon the red light, thereby ensuring its observance.
* * * * *