Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
TITLE
TRAFFIC SIGNAL SNOW SHIELD
CROSS REFERENCE APPLICATIONS
This non-provisional application claims priority from
provisional application serial number 62534412 filed July 19,
2017 and provisional application number 62559289 filed September
15, 2017.
FIELD OF THE INVENTION
The present invention relates to traffic signal visors and
shields that help prevent a snow buildup on an LED traffic light
lens.
BACKGROUND
Traffic lights are well known and typically comprise a trio
of lights aligned vertically. Depending on which light is
illuminated, a motorist facing the light on an associated street
is directed whether to proceed through an intersection, proceed
with caution, or to stop and not enter the intersection. The
ability for motorists to clearly see which of the three lights
is illuminated from a distance is critical in ensuring the safe
flow of traffic through an intersection.
To prevent the buildup of snow and ice on the colored
lenses of the lights and to help shade the lights in bright
sunlight, many traffic lights include visors (or fairings) that
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Date Recue/Date Received 2021-08-16
extend around the lights except for an opening at the bottom
thereof to permit water to flow and snow to fall therefrom.
Sometimes these visor enclosures have performed as desired.
In the past under certain circumstances, such as heavy snow
storms with blowing snow, snow tended to build up in front of
the lenses of prior art traffic signals; however, because the
underlying lights were incandescent they gave off a significant
amount of heat that melted the snow and prevented the lenses
from becoming covered, thus maintaining suitable visibility.
In the recent past, state and federal government
regulations have dictated that all traffic lights be changed
over to brighter and presumably more visible LED type bulbs.
Since LED lights are much more energy efficient than
incandescent lights of similar output, they do not generate
sufficient heat to melt snow that can accumulate on the lens in
heavy snow storms.
A brief summary of some prior art references follows below.
Pub.No. U.S.2012/0119672 to Meyer discloses a dome shaped
shield placed at the outermost edge of a traditional visor.
U.S Pat. No. 9,581,308(2017) to Watkins discloses a
cylindrical lens having a slanted convex front cutout, the lens
fits around the LED traffic light. The slanted cutout supports a
domed shield in front of the traffic light.
JP 2003109187A [Munesawa] discloses a display in which
snowing on the surface of the display can be prevented, a light
unit 5A of a signal lighting having a hood 10 and a transparent
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snowing-proof plate 31 is arranged in front of this light unit
5A while being inclined forward. This snowing-proof plate 31 is
incorporated inside the hood 10 through a packing 32, and a
space 34 is formed from a transparent resin cover 6. Wind 36 is
decelerated on the surface of the snowing-proof plate 31,air
uniformly flows obliquely downward along with the relevant
surface and blows out snow on the snowing-proof plate 31
(Abstract; Figure3).
U.S.Pat.No.5,785,418 [Hochstein] discloses casing 42
surrounding the base 36 of the heat sink, and insulating
material 44 is disposed between the base 36 and the casing 42 to
limit heat transfer to the heat sink from outside the casing
42,i.e., from sources other than the LEDs 28. Transparent cover
46 is retained within the shell 38 by a weather seal 48, casing
14 defines a heat shield surrounding the thermally insulating
material 44 to act as an additional barrier to heat transfer
into the heat sink 36 (Figure8; Column 5, Lines 35-65; Claims 1-
7).
The following non-patent literature articles are noted:
1."SNOW SENTRY", Fortran, fortrantraffic.com, accessed:
February 2018. http://www.fortrantraffic.com/shop/signals
/snow-sentry-snw008/.Discloses a device that when installed
over the led module reduces the potential build-up of snow
and ice on the lens.
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2."Snow Scoop Visor," McCain ID, mccain-inc.com, accessed:
February 2018. https://www.mccain-
inc.com/products/signals/signalaccessories/scoop-tunnel-
visor discloses advanced signal visors that combat snow
buildup on signal lenses in cold climates, louvered vent on
top, coupled with an open bottom help funnel air across the
face of the lens reducing snow accumulation.
3."Safetran Systems CLS-20R Railroad Signal Light," eBay,
ebay.com, seller: wcartey, ebay item number: 282807541745,
February 8, 2018. https://www.ebay.com/itm/Safetran-Systems-
CLS-20R-Railroad-Signal-Light-/282807541745 discloses a
traffic signal with an extended shield.
4.Adreama,"Traffic light visor," adreama.blogspot.com, June
9, 2012. http://adreama.blogspot.com/2012/06/traffic-light-
visor.html discloses set of drop-down visors which could be
deployed for non-functioning traffic lights, could be
remotely electronically deployed, allowing rapid response to
traffic light failure, would be on a separate circuit to
avoid both the traffic lights and the visors being out of
action simultaneously.
What is needed in the art is a Manual on Uniform Traffic
Control Device (MUTCD) compliant wind accelerating traffic
shield that uses ambient wind to form a high speed wind
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blower across the face of an LED traffic signal. The present
invention places a transparent cone over the LED traffic
signal lens. A cylindrical opaque wing or visor surrounds
the peripheral base of the cone, thereby creating a
Bernoulli's effect wind across the traffic signal lens.
SUMMARY OF THE INVENTION
The main aspect of the present invention is to mount a
transparent cone over an LED traffic signal, and surround the
cone with a cylindrical shield, thereby using a Bernoulli
effect to accelerate ambient wind toward the LED traffic
signal and cause a vacuum in front of the LED traffic signal,
thereby forcing snow on the LED traffic signal outbound away
from the base of the cone.
Another aspect of the present invention is to enhance the
vacuum in front of the LED traffic signal.
Another aspect of the present invention is to provide a
retrofit kit to a prior art visor that mounts a cone inside
the visor that forms the vacuum.
Another aspect of the present invention is to increase the
time of freezing of the LED traffic signal by speeding up the
flow of air across the LED traffic signal, thereby reducing
the buildup of water on the LED traffic signal, wherein water
captures snowflakes.
Another aspect of the present invention is to minimize any
quick freezing on the LED traffic signal because in 5 to 15
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minutes an LED traffic signal can freeze over causing
accidents, and it takes hours for the frozen snow to melt,
after ambient goes over 32 F.
Embodiments of an Improved Signal Fairing and Head
Embodiments of the present invention comprise an improved
signal fairing and head configured to replace currently used
visors. Advantageously, the design and configuration of the
head prevents the buildup of snow and ice on the lens cover by
directing the wind associated with a storm around the interior
of an aerodynamic visor and transparent conical lens cover in
such a manner as to blow any snow therefrom, and prevent it
from settling on surfaces that would hinder the light's
visibility.
Several embodiments are disclosed of a signal
head for use with a traffic signal device
incorporating an improved frustoconical fairing and
conically shaped transparent lens cover. The fairing
and lens cover are typically secured to a light
fixture that utilizes an LED bulb. The design of the
fairing in combination with the lens cover act to
prevent the buildup of snow and ice over the lens of
the light fixture that could cause the underlying
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light to be obscured even when illuminated, thereby
not giving viewing motorists adequate notice as to
what traffic has the right of way at an intersection.
One embodiment is best characterized by the following
parts or components: (i) the light fixture, which typically
includes an LED bulb; (ii) a fairing with an aerodynamically
derived cross sectional profile; (iii) a conically shaped lens
cover; and (iv) a plurality of screws and/or other fasteners
to secure the fairing and lens cover to the light fixture.
The light fixture, itself, can be of a fairly
conventional design comprising a housing having a socket
to receive a light bulb at a back end including a means
to connect electrically to the signal light assembly. The
bulb can be of any suitable type but is typically a high
powered LED bulb. LED bulbs are largely mandated by state
and federal agencies for being both brighter and
consuming far less power than legacy bulb technologies.
The front end is typically characterized by a relatively
large red, green or yellow colored lens. A flange and/or
ring bracket is provided around the front edge of the
body and is used to both hold the lens to the body and to
provide a means for connecting a fairing to the light
fixture. The bracket is also used to secure the lens
cover to the light fixture.
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The fairing includes a ring or other means to
receive the fasteners at its distal end and extends
forwardly therefrom comprising an expanding generally
frustoconical shape. The bottom of the fairing is open
with the opening having an extent of about 45 degrees
but which can vary significantly.
The cross section of one embodiment of the fairing
wall is aerodynamically configured having a rounded
leading edge, a largely straight inside wall that is
canted outwardly at a small angle and more significantly
outwardly angled outer wall. The inside diameter of the
fairing varies a relatively small amount from the distal
end to the proximal end where it intersects with the
leading edge, and the outside diameter variance is much
more pronounced from the distal end to the proximal end.
Accordingly, the fairing is much thicker proximate the
leading edge intersection than it is proximate the
distal end mounting ring. There is a gap provided between
the light fixture and the distal end of the fairing.
Typically threaded fasteners (screws) are distributed
around the circumference of the light fixture mounting
bracket and the fairing ring. These fasteners and
associated hardware are used to both secure the fairing to
the signal head assembly, as well as space the distal end
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of the fairing a predetermined distance from the light
fixture. A predetermined distance of about 0.375- 1.25"
inches is desirable, but other spacings can be used in
variations.
The rounded leading edge creates an overpressure
situation at the front of the fairing to slow down blowing
snow and channel a significant portion of it over the
outside of the fairing. The frustoconical shape of the
exterior wall of the fairing helps create a low pressure
area behind the leading edge where low pressure vortices
are created. The lower pressure helps pull the snow slowed
down in front of the leading edge around the fairing
rather than into it. The low pressure region also acts to
help pull snow that has entered the interior of the
fairing out through the bottom opening and through the
gap between the fairing and the light fixture at the
fairing's distal end.
The fairing can be made of any suitable material,
however, lightweight materials are preferred given the
relatively large volume of the fairing. In one
variation the fairing can comprise a foam core having a
plastic or fiberglass skin thereover providing light
weight and the necessary strength.
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The transparent conically shaped lens cover includes
a circular flange extending from its distal outer edge.
When installed the flange is compressed between the
mounting bracket of the light fixture and the lens to hold
it securely in place. The lens cover is made of any
suitable transparent material but most typically it is
comprised of a plastic, such as polycarbonate.
The conical shape acting in concert with the inside
wall of the fairing causes the speed of any snow received
into the fairing to increase as it penetrates deeper
therein reducing the chance that the snow will settle on
the surface of the lens cover or fairing inside wall. The
increased speed also increases the pressure at the back
of the fairing which pushes the snow out of the bottom of
the fairing and through the gap between the fairing and
the light fixture into the lower pressure region on the
outside thereof.
A second embodiment is a kit that can take a
standard visor, offset its base away from the LED lens,
and add the cone. A third embodiment combines a custom
visor with the cone.
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Inventive Aspects
The various inventive aspects of embodiments of the
signal head assembly and associated fairing and conical
lens cover include but are not limited to the following:
A) A signal head assembly for a traffic signal, the
assembly including a light fixture, a frustoconical
fairing, and a conically-shaped lens cover wherein the
fairing has a rounded leading edge and tapers in
outside diameter towards a distal end.
B) The signal head assembly of (A) wherein there is
a gap between the distal end of the fairing and the
light fixture.
C) The signal head assembly of (A) wherein the bottom
of the fairing is open and has an extend of about 45
degrees plus or minus 15 degrees.
D) The signal head assembly of (B) wherein the fairing
is attached to the light fixture by way of a plurality
of elongated fasteners.
E) A fairing and lens cover combination configured to
prevent the buildup of snow and ice over the lens of
a light fixture that would otherwise obscure its
visibility.
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The method of using the signal head assemblies of (A)-
(D) to prevent the buildup of snow over a light fixture
lens in a snow storm.
G) The signal head assembly of (A) wherein the conical
lens cover is secured to the light fixture by way of a
ring mounting bracket that also acts to secure the
light fixture lens to the light fixture.
H) The signal head assembly of (A) wherein the
fairing is thicker proximate the leading edge
than proximate the distal end.
Other aspects of this invention will appear from the
following description and appended claims, reference being
made to the accompanying drawings forming a part of this
specification wherein like reference characters designate
corresponding parts in the several views.
These and other features and advantages of the Traffic
Signal Snow Shield reside in the construction of parts and
the combination thereof, the mode of operation and use, as
will become more apparent from the following description,
reference being made to the accompanying drawings that form a
part of this specification wherein like reference characters
designate corresponding parts in the several views. The
embodiments and features thereof are described and
illustrated in conjunction with systems, tools and methods
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which are meant to exemplify and to illustrate, not being
limiting in scope.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.lA is an exploded view of a first embodiment snow shield.
Fig.1B is a front perspective view of the first embodiment
snow shield.
Fig.2 is an exploded view of a second embodiment snow shield.
Fig.3 is a longitudinal sectional view of the Fig.2
embodiment.
Fig.4 is a front perspective view of the cone.
Fig.5 is a front perspective view of the Fig.2 embodiment.
Fig.6 is a rear perspective view of the Fig.2 embodiment.
Fig.7 is a front perspective view of the standoffs.
Fig.8 (prior art) is a front perspective view of a snow
buildup on an LED lens.
Before explaining the disclosed embodiments in detail, it
is to be understood that the embodiments are not limited in
application to the details of the particular arrangements
shown, since other embodiments are possible. Also, the
terminology used herein is for the purpose of description and
not of limitation.
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DETAILED DESCRIPTION OF THE DRAWINGS
Referring first to Figs.1A, 113 a snow shield is labeled 10.
A prior art LED bulb base 1 is square. A bulb (not shown) is
convex within the base 1. Mounting posts 2 are secured in holes
3 of the base 1. Cylindrical collars 4 slide over posts 2, and
the collar supports 5 of the standoffs 6 slide over the collars
4. The collar 7 is mounted on the supports 5 via nuts 8 that
thread onto posts 2. The standoffs 6 form a gap G (about 5/8
inch) between the base 1 and the collar 7. The snow slot is
labeled 15.
The cone 9 affixes to the collar 7 via posts 2 and nuts 8.
The cone 9 is transparent and preferably plastic. The wing
assembly 11 consists of an outer wing shaped (plastic) shroud 12
having a cylindrical inner wall 13 secured with rivets 14. The
nut 8 secures all items 12,13,9,7 to the posts 2.
The incoming wind W enters the shroud 12 (which can be 3 to
4 inches wide) with a wide distance dl between the inner wall 13
and the cone 9. The wind W is then forced into a narrow distance
d2 between the inner wall 13 and the base 16 of the cone 9, and
the wind is accelerated by the Bernoulli principle to exit the
gap G as shown by arrows BER. This accelerating air BER forms a
vacuum across the lens in the base 1 which removes any snow from
the lens. The cone 9 can be about 11 inches tall with a 45
degree flange. The shroud 12 extends about one inch beyond the
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cone 9. The snow shield 10 is designed to withstand winds of up
to 100 mph. The base 1 is a square 13 inches a side with a
standard lens diameter of 11.4 inches. The wind travelling along
the outside of wing 12 is shown by arrow AA. It can add to the
force of the vacuum at the surface of the lens.
Bernoulli's principle
Fluid dynamics, Bernoulli's principle states that an
increase in the speed of a fluid occurs simultaneously with a
decrease in pressure or a decrease in the fluid's potential
energy. The principle is named after Daniel Bernoulli who
published it in his book Hydrodynamica in 1738. Although
Bernoulli deduced that pressure decreases when the flow speed
increases, it was Leonhard Euler who derived Bernoulli's
equation in its usual form in 1752_ The principle is only
applicable for isentropic flows: so when the effects of
irreversible processes (like turbulence) and non-adiabatic
processes (e. g. heat radiation) are small and can be
neglected. Bernoulli's principle can be applied to various
types of fluid flow, resulting in various forms of Bernoulli's
equation; there are different forms of Bernoulli's equation
for different types of flow. The simple form of Bernoulli's
equation is valid for incompressible flows (e.g. most liquid
flows and gases moving at low Mach number). More advanced
forms may be applied to compressible flows at higher Mach
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numbers. Bernoulli's principle can be derived from the
principle of conservation of energy. This states that, in a
steady flow, the sum of all forms of energy in a fluid along
a streamline is the same at all points on that streamline.
This requires that the sum of kinetic energy, potential
energy and internal energy remains constant Thus an
increase in the speed of the fluid - implying an increase
in its kinetic energy (dynamic pressure) - occurs with a
simulLaneous decrease in (the sum of) its potential energy
(including the static pressure) and internal energy. If the
fluid is flowing out of a reservoir, the sum of all forms
of energy is the same on all streamlines because in a
reservoir the energy per unit volume (the sum of pressure
and gravitational potential p g h) is the same everywhere
Bernoulli's principle can also be derived directly from Isaac
Newton's Second Law of Motion. If a small volume of fluid is
flowing horizontally from a. region of high pressure to a
region of low pressure, then there is more pressure behind
than in front. This gives a net force on the volume,
accelerating it along the streamline. Fluid particles are
subject only to pressure and their own weight. If a fluid is
flowing horizontally and along a section of a streamline,
where the speed increases it can only be because the fluid on
that section has moved from a region of higher pressure to a
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region of lower pressure; and if its s peed decreases, it can
only be because it has moved from a region of lower pressure
to a region of higher pressure. Consequently, within a fluid
flowing horizontally, the highest speed occurs where the
pressure is lowest, and the lowest speed occurs where the
pressure is highest.
Referring next to Fig.8 (prior art) the base 1 has lens
82. A standard shroud 80 has the typical snow slot 81. The
wind W carries snow with it which sticks on the cold surface
of the lens as labeled 83outbound as shown in Fig.1B arrows
BER.
Referring next to Figs. 2-7 the snow shield 200 mounts on
the same prior art base 1. A mounting ring 20 secures the
cone 9 to the base 1. The shroud 21 is cylindrical having the
snow slot 15.
Fig.3 shows the Bernoulli's principle of the air
traveling from a wide diameter passageway dl to a narrow
passageway d2 to egress from the base 1 via gap G as shown by
arrows BER. Gap G can range from about 14 inch to about 11
inch.
While a number of exemplifying features and embodiments
have been discussed above, those of skill in the art will
recognize certain modifications, permutations, additions and
subcombinations thereof. No limitation with respect to the
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specific embodiments disclosed herein is intended or should be
inferred.
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