Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
BLAST WIPER FOR MOTOR VEHICLE LIGHTS
FIELD OF THE INVENTION
The present invention relates to devices for cleaning motor vehicle
lights, and more specifically, to a wiping system for cleaning snow
accumulating on the rear lights of a transport trailer, using intermittent
gushes of air.
5 BACKGROUND OF THE INVENTION
A common problem with driving a transport truck during the winter
is that the turbulence created by the moving transport swirls up flurries of
snow which pack against the rear end of the trailer, covering the braking
and tllrning lights of the vehicle. The operator of the transport must stop
10 frequently, especially at night, to clean the light lenses to prevent accident
from a following driver.
One difficulty in providing light wiping function on a transport
trailer is that a source of power for operating such device is often a
restricted one. The number of electrical conductors in the service cable
15 from the truck to the trailer is, in many cases, limited to power supply to
the position lights, signal lights, brake lights, and a third axle lifting
mech~ni.~m. Similarly, the air power supply to the trailer brake actuators
is conforming to strict safety regulations, and a taping into an air line must
not alter the performance of the braking system.
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Another obstacle in providing light wiping functions on a transport
trailer is that the wiping device must be adaptable to existing trailers with
as few modifications as possible. Furthermore, if the installation is done
by a person having limited knowledge of electricity and pneumatic, the
installation instructions must be easily understood such that an installer will
not tamper with the safety aspects of the vehicle.
A number of prior art devices have been developed for cleaning light
lenses, and especially for cleaning the head lights of a vehicle having a
compressed air system. For example U.S. Patent no. 4,505,001 issued Mar.
19, 1985 to Fasolino describes a high pressure nozzle in combination with
a flexible tube whipping from side to side against the surface of the light.
The high pressure nozzle discharges cleaning fluid against the surface of
the lens, while the whipping effect of the tube is obtained by forcing a
stream of air under high pressure through the tube.
Another example of an air wiping system is described in U.S. Patent
no 5,083,339 issued Jan. 28, 1992 to Bristow. The device uses a wiper
arm driven by a pneumatic motor. The arm has a plurality of apertures
through which a mixture of air and cleaning fluid is ejected under high
pressure against the surface of a heafllight
In both the previously described inventions, the operation of the
wiper is continuous upon energizing the system by the driver. The flow of
air from the vehicle's air reservoir is also continuous during the operation
of the wipers. Such a constant outflow of air from a truck's air brake
system is not desirable because it may affect the performance of the air
brake system of the vehicle, as will next be explained.
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According to an aforesaid comment, an air brake supply system of
a vehicle is made to comply to safety standards from regulatory bodies.
For example, an air brake supply system for a transport truck must
comprise an air reservoir on the truck which has the volume of at least 12
times the combined volume of all service brake chambers at a maximum
displacement of the pistons or diaphragms. Similarly, the trailer must be
equipped with one or more air reservoirs having a combined volume of air
that is at least 8 times the combined volumes of all service brake chambers.
The air pressure in those reservoirs must be m~int~ined preferably at above
0 100 psi, and not less than 90 psi. The compressor of the truck must be
capable of building air pressure within the system after every use of the
brakes. Typically, the requirement is that the compressor must be capable
of building up air pressure in the air system from 85 psi to 100 psi within
25 seconds.
Thus, an air wiping device which continually drains air from the air
brake system may require a larger compressor on the vehicle to ensure
compliance to the required performance of the safety standard. Moreover,
such a continuous outflow of air of the prior art devices may cause the
compressor to engage often to make up the system pressure, and may
increase thereby the fuel consumption of the vehicle.
Other air wiping systems to remove snow from vehicle mirrors and
windows are described in U.S. Patent no. 5,097,563 issued on Mar. 24,
1992 to Cowan, and in U,S. Patent 5,140,719 issued on Aug. 25, 1992, also
to Cowan. These systems comprise a blower to deliver a pre-heated high
velocity air stream to nozzles located adjacent the surfaces to be cleaned.
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An installation of such a blower and a heater under a transport
trailer would likely require intricate housing to protect the devices and
nozzles from the climate and road splashes. Such installation would also
probably require the upgrading of the service cable from the truck to the
5 trailer to supply electrical energy to the blower and the heater.
Another prior art device for cleaning the lenses of vehiclels lights is
disclosed in C~n~ n Patent no. 1,131,858 issued on Sept. 21, 1982 to
Savage et al. The system comprises a source of compressed air, pressure
accl1m~ tors, regulator valve, check valve, directional valve, a reservoir of
10 washing fluid and delivery nozzles.
Likewise, the complexity of the proposed piping of this invention
renders it difficult for retrofitting the equipment on a transport trailer by a
person unexperienced with pneumatics.
Furthermore, another inconvenience with an air wiping system
l 5 installed near the rear lights of a transport trailer is that when the system is
not in use, the orifice of a prior art nozzle may freeze from snow and slush
accllm~ ting thereon, rendering thereby the system inoperative.
SUMMARY OF THE INVENTION
In the present invention however, there is provided a blast wiper for
20 cleaning snow from the li~hts of a vehicle having a compressed air system.
The blast wiper comprises automatic control means for regulating the
outflow of air from the compressed air system into intermittent gushes of
air. The blast wiper comprises also supply tubing for connecting the
automatic control means to the compressed air system, nozzle means for
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directing the i~ lelll gushes of air toward a surface of the vehicle's
light, and delivery tubing for cormecting the automatic control means to the
nozzle means.
The most significant advantage of the blast wiper is that intçrmittent
5 gushes of air directed toward a surface of the rear lights of a vehicle are
sufficient to m~int~in the rear lights visible when that vehicle is driving in
snowy conditions, while preventing excessive outflow of air from vehicle's
alr reservoir.
Considering that a layer of snow is not completely opaque, a
o substantial thickness of snow can accllm~ te on the surface of a light lens
before a signal from that light cannot be seen from a following driver.
Therefore, an air blast wiping system which cleans the light surface at
regular intervals is sufficient to m~int~in safe driving conditions, while
using a minimum volume of air from the compressed air system.
In accordance to another aspect of the present invention, the nozzle
of the blast wiper is placed near a lower quadrant of the light surface. The
nozzle is further oriented to deflect a gush of air in a tangential upward
direction relative to the surface of that light, whereby a layer of snow on
that surface is lifted off and blown away by the gush of air, in a patch-like
20 formation.
The additional advantage of this particular positioning of the nozzle
is that a short blast directed tangent to and from below a snow covered light
lens compresses the layer of snow upwardly and removes the layer as a
large piece. Therefore, such positioning of the nozzle further ensures that
25 a relatively small volume of air from the compressed air system of the
vehicle is efficiently used to clean the light lens entirely.
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In accordance with a further aspect of the present invention, the
nozzle means is a popping nozzle comprising a spring biased expandable
piston chamber and apertures co~ icating inside the piston chamber
when the piston chamber is expanded from a nominal air pressure applied
5 therein. Therefore the air flow directed through the piston chamber and
exiting through the apertures is at least at that nominal pressure.
The popping nozzle of the present invention further ensures that the
i"""" volume of air drained from the air brake reservoir is used to its
full pressure and velocity potential.
In accordance to another aspect of the invention, the air blast wiping
system for transport trailer is a retrofit kit comprising a protection valve formounting on the compressed air system of the transport trailer, for
preventing an outflow of air from the air system when a pressure in the air
system is below a pressure setting of the protection valve, and automatic
15 control means for regulating the outflow of air from the compressed air
system into intellnilLelll gushes of air. The retrofit kit also comprises a
single supply line tubing for connecting the protection valve to the
automatic control means, nozzle means, and delivery tubing for connecting
the automatic control means to the nozzle means.
The retrofit kit has pre-wired and pre-tubed components such that
an installation of the air blast wiping system on a transport trailer by a
person unexperienced with pneumatic does not colllplol--ise the safety
aspects of the air brake system of the vehicle.
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BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiment of the invention will be further
understood from the following description, with reference to the drawings
in which;
5 - Figure 1 illustrates a rear view of a transport trailer, and a typical
location of the sign~lling lights.
- Figure 2 is a piping schematic showing a preferred connection of
the present invention to an air brake reservoir.
- Figure 3 is an electrical schematic of the control circuit for the
I o present invention.
- Figure 4 illustrates the major components of a retrofit kit of the air
blast wiping system.
- Figure 5 shows the interior of the control box of the retrofit kit of
the present invention.
15 - Figure 6 illustrates a preferred mounting of an air blast nozzle on
a double light fixture. The double light fixture is an enlargement of
detail 6 of Figure 1.
- Figure 7 illus~ates an enlargement of detail 7 of Figure 1 showing
a preferred mounting of an air blast wiper on a single light fixture.
20 - Figure 8 is a second preferred installation of a blast wiper under a
totally enclosed double light fixture.
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- Figure 9 is a cross-section of a popping nozzle.
- Figure 10 is an exploded view of a popping nozzle.
- Figure 11 is a perspective view of a popping nozzle.
- Figure 12 is a side view of a popping nozzle mounted on a light fixture surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Figure 1, there is illustrated a transport trailer 20, and
a typical location of braking and turning lights 22. Some trailers, especially
the newer models, have a single tllrning light 24 mounted near the middle
10 of each lower side of the trailer 20, as illustrated on detail 7, for warning a nearby driver during a lane change.
The control box 76 of the rear light wiping system of the present
invention is preferably mounted on the rear end of the trailer 20, where a
length of tubing to the nozzles is ~ Another preferred location for
15 this control box 76 is under the lower driver side of the trailer near the
front end thereof, where the operator can energize the blast wiper without
having to walk to the rear of the vehicle.
Referring now to Figure 2, there is illustrated a piping schematic of
a typical air brake piping system for a transport trailer. There is also
20 illustrated the preferred piping instructions for an installation of the
preferred embodiment of the invention. A typical air brake piping system
comprises gl~f1h~tld connectors 26 for mating with the air supply lines on
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the tractor truck, and air supply piping 28, connecting the gl~-lh~nd
connectors 26 to a full function valve 30. The full function valve 30 is
mounted on an air reservoir 32, and provides air pressure to the brake
chambers 34, through an emergency parking brake supply line 36, and a
5 service braking supply line 38.
The air reservoir 32 of a transport trailer is normally equipped with
several threaded fittings 40 for mounting for example, a pressure gauge, a
drain valve, or ~-lxili~ty equipment of that kind in an orientation which best
10 suits the location of the reservoir.
The supply line for the blast wiping system of the invention is
connected to one of these fittings 40. The supply line for the blast wiper
comprises a protection valve 42, a manual shut off valve 44, an inlet
flexible tube 46 connected into a solenoid directional valve 48. The
15 delivery line of the blast wiping system comprises an outlet flexible tube
50 connected into air delivery nozzles 52.
The m~nl1~1 shut-offvalve 44 enables a person to close the system
completely during non-use periods such as during the summer time. The
protection valve 42 is a pressure controlling valve which allows full flow
20 therethrough when the pressure inside the air reservoir is above a preset
level of the valve 42, and which closes completely when the air pressure is
under the preset level. A typical preset level for a protection valve 42 on
an air brake system of a transport trailer is 90 psi. The protection valve 42
prevents outflow from the reservoir when such outflow could complolllise
25 the braking performance of the vehicle.
The solenoid directional valve 48 is controlled by two timers 54,56.
A first timer 54 controls the span between each blast, while the second
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timer 56 determines the duration of the air blast. Accordingly, a preferred
time span between bursts of air is about 5 to 10 minutes, and a preferred
duration of the air blast is 1 to 3 seconds.
The Figure 3 is an electrical schematic of the control module
5 controlling the operation of the solenoid inside the directional valve 48.
The control module comprises a first timer 54 which is a flicker type timer
where the output contacts are alternatively turned on and off as long as the
input signal is m~int~ined thereon. The control module also comprises a
second timer 56 which is an off delay timer.
The coil of the first timer 54, labelled as Tl, energizes a first
normally open relay 60, which in turn energizes the solenoid 48, and the
coil of the second timer 56, labelled as T2. A normally closed contact on
a second relay 62 in series with first relay 60 responds to the second timer
56, to shut the power off solenoid 48 after the preset time interval of the
15 second timer 56.
The circuit also comprises a first manual on-off switch 64 to
energize the circuit, and a second push button switch 66 to bypass relay 60
and relay 62 for the purpose of verifying the operation of the nozzles 52.
The circuit is preferably energized by connecting termin~l~ 70 and 72 to
20 the electric circuit of the park lights of the transport trailer such that the
system is operative only when the park lights are turned on.
Referring to Figure 4, the retrofit kit for a blast wiping system for
a transport trailer comprises a moisture resistant control box 76 cO~ g
the pre-wired electrical components, and a pre-tubed solenoid valve 48.
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The retrofit kit is sold in a fully assembled format having a supply
flexible tube 46, a m~nll~l shut off valve 44 and a protection valve 42 with
a fitting 43, for cormecting into an air brake reservoir. The retrofit kit
further comprises a delivery flexible tube 50 connected to one or more
S nozzles 52 through a T-fitting 51.
It will be apparent to those skilled in the art of compressed air
systems that the retrofit kit of the present invention may also be connected
to the pressure piping of the air brake system, whenever such installation
would be more appro~.iate to a particular type of vehicle.
The installation instructions for the retrofit kit herein described are
simplified to four major steps, as follows;
a) to connect fitting 43 to the air system piping, or to the air reservoir
32 of the trailer,
b) to connect electrical power supply wiring from the park lights
l 5 circuit of the trailer into the on-off switch 64 of the control box 76,
through a water-tight connector 84,
c) to install the delivery nozzles 52 adjacent the light lenses to be
cleaned, and
d) to optionally shorten the flexible tubes 46 and 50 to provide a
proper fit under the trailer.
The advantage of presenting the air blast wiping system in the form
of a pre-assembled retrofit kit is that the possibility of tampering with the
air brake supply system by an unexperienced installer is practically
elimin~ted.
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-
The moisture resistant control box 76 of the retrofit kit is better
illustrated on Figure 5. The enclosure 76 contains a directional solenoid
valve 48, a first timer 54, a second timer 56, a manual on-off switch 64,
and a push button switch 66. The electrical components are pre-wired, and
5 the timers are preferably preset at the factory. Similarly, the solenoid valve 48 is pre-tubed upon assembling this control module.
The control box 76 has a cover 78 with a sealing strip 80 and a
closing latch 82, to provide easy access inside the enclosure by the
10 operator, while protecting the control components from road splashes and
other conditions natural to road driving.
For the same reasons, the electric supply wiring is routed inside the
control box 76 through a watertight electrical connector 84. Similarly, the
push button of manual bypass switch 66 is preferably a watertight panel
15 mount type where the button is exposed on the outside surface of the
control box 76, such that the operation of the nozzles 52 may be verified
without opening the control box 76.
Referring now to Figure 6, 7 and 8, there is illustrated a nozzle 52
20 which is installed near a lower quadrant of both the braking light 90 and thetur~ing light 92. The nozzle 52 is installed through the front surface 94 of
braking and tllrning light fixture 22 or turning light fixture 24, or onto a
bracket 96 under a fully enclosed braking and turning light fixture 98.
Optionally, a rear double light fixture 22, or a single side light
25 fixture 24 having a nozzle incorporated in its front surface may be
m~nllf~ctured as an integral component, and included in the retrofit kit of
the invention.
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The nozzle 52 has either two slotted openings for directing a gush
of air toward light lenses on both sides of the nozzle, or one slot for
directing air toward one light lens of a single tllrning light fixture 24.
The slots of the nozzle 52 are oriented to discharge a gush of air in
an upward direction tangent to the surface of the lenses to be cleaned. The
reason for this is that snow which acc-lm~ tes on the surface of the lenses
is compressed upwardly by the blast, causing a layer of snow to lift off in
a patch-like formation exposing thereby the entire surface of the light. This
is a commendable advantage over a stream of air coming from the top of
the lenses where gravity helping, the layer of snow is blown in small
fragments. In this later case, one short blast of air may often be not
sufficient to clean the surface of the lenses completely.
The preferred embodiment of the delivery nozzle 52 is a popping
nozzle as illustrated on Figures 9 to 12. The popping nozzle 52 comprises
a hollow threaded stem 100 machined to receive a tube fitting 102,
whereby delivery tube 50 is connected thereto. The nozzle also comprises
a mounting nut 104, a backing housing 106 and a sliding housing 108.
The sliding housing 108 is slidingly held against the backing
housing 106 by means of a spring 110 retained on a high nut 112 by a snap
ring 114 and a flat washer 116. The backing housing 106 and the sliding
housing 108 are preferably made of a plastic material resistant to
deterioration from winter road conditions.
The spring assembly of the nozzle is enclosed in a cavity 118 of the
sliding housing 108, and enclosed by a cover 120 which is made to
snappily engage in an internal groove 122 in cavity 118. The cover 120 is
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also preferably made of a similar plastic material as the backing housing
106 and sliding housing 108.
The sliding housing 108 has a circular shoulder 124 which is
dimensioned to slide fittingly inside a cylindrical portion 126 of backing
housing 106. The circular shoulder 124 and the cylindrical portion 126
mate with one another to form an expandable piston chamber 128.
The air flow from tubing 50 is introduced into the piston chamber
128 through a passage 130 on the central axis of stem 100, and through
slots 132 on the high nut 112. The slots 132 on the high nut 112 are longer
than the engagement of the high nut 112 onto the stem 100, whereby the
exllelllilies of slots 132 provide openings 134 to let air enter the piston
chamber 128.
The spring action on the sliding housing 108, and the axial
displacement of sliding housing 108 on high nut 112 cause a sudden
opening of the nozzle 52 only after a nominal pressure has built up inside
the piston chamber 128. Thus the air flow from the nozzle 52 is a bursting
flow, wherein the typical and ineffective initial seeping of conventional
nozzle from restriction in the tubing system upon opening the solenoid
valve is elimin~ted. Hence the entire volume of air taken from the air brake
reservoir 32 is advantageously used to its full pressure and velocity
potential.
The circular shoulder 124 of sliding housing 108 has circumferential
slots 136 at one or two locations around the perimeter thereof, depending
upon whether the nozzle is designed for installation on a double light
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21 39402
fixture or on a single light fixture. The length of each slot 136 covers
approximately an arc of between 30~ to 90~, and preferably between 40~
and 60~. Thereupon, the dotted lines 138 on Figures 6, 7 and 8 represent
an air flow pattern with an arc length for slot 136 of between 40~ and 60~.
When the blast wiper nozzles of the present invention are installed
on a transport trailer having light lenses of 4" in diameter, the backing
housing 106 has a preferred overall diameter of about 1-1/2" and a
preferred thickness of about 1/4". The nozzle is preferably installed at a
location which is about 4" to 5" from the centre of a light. When the
lo nozzle is installed on a double light fixture, the preferred location is also
at 4" to 5" from each light of the fixture.
Con~ elllly with the above dimensions, the backing housing 106
has a front frustum 140 having a conical surface following an angle of
between 15~ and 25~, and preferably an angle of about 2~ from a plane
perpendicular to the longitudinal axis of the nozzle. Similarly, the sliding
housing 108 has a flared circular edge 142 which matches the shape of the
front frustum 140, such that a stream of air expelled from within the piston
cavity 128 through slot 136 is directed toward the surface to be cleaned,
and deflected thereon in a tangential direction, under the layer of snow to
be removed.
The backing housing 106 has further a rear frustum 144 having a
maximum diameter near the front frustum 140. The purpose of this rear
frustum 144 is to prevent the accllmlll~tion of melting or falling snow near
the intersection of the flared edge 142 and front frustum 140, and to
prevent thereby the obstruction by freezing of the nozzle 52.
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Likewise, the circular shoulder 124 has a series of apertures 146
equally spaced in a same circumferential alignment than slot 136. Thus at
every operation of the nozzle 52, a small amount of air is expelled through
these apertures 146 to clean dust and snow from between the flared edge
142 and the front frustum 140, and hence to m~int~in the telescoping
portion of the nozzle 52 free from freezing or obstructing substances.
Referring now specifically to Figures 10 and 12, the sliding housing
108 has an hexagonal opening 148 along its axis of displacement such that
it slides fittingly over the high nut 112, while retaining its radial orien-
tation relative to the high nut 112. To fu~ther retain the orientation of the
sliding housing 108 relative to the light lenses to be cleaned, the nozzle 52
is mounted through a hole in mounting plate 94, and retained in place with
the slots 136 oriented toward the light lenses, by tigll~e~ g mounting nut
104 until mounting plate 94 is pressed tightly against backing housing 106.
While the pl~relled embodiment of the invention has been described
as a retrofit kit with preset timers and popping type, self cleaning nozzles,
other method of marketing the blast wiping system, and other type of
nozzles and control devices are possible without altering the structure of
the invention.
Therefore, the preferred embodiment of the invention as described
herein is not limited thereto, and it will be apparent to those skilled in the
art that numerous modifications form part of the present invention insofar
as they do not depart from the spirit, nature and scope of the described and
claimed invention.
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