Note: Descriptions are shown in the official language in which they were submitted.
CA 02649084 2009-01-08
Heated Windshield Wiper
Field Of Invention
The present invention relates to the general art of motor vehicles, and to the
particular field of
windshield wipers.
Background to the Invention
Windshield wipers are utilized with vehicle windshields in order to maintain a
clear view for
the driver of the vehicle from rain, snow or other debris. During freezing
rain or snow
conditions, precipitation often accumulates upon the windshield wiper,
including the wiper
blade, thereby preventing the windshield wiper blade from making contact with
the
windshield so as to leave a "blurred" windshield that is extremely dangerous
for drivers.
More specifically ice builds up on the leading edge of the blade to loose
partial and often
most of its contact with the windshield. Furthermore driving in winter
conditions often
causes the problem of snow and ice buildup on the blade thereby lifting the
blade entirely off
the windshield.
Other problems can be encountered when the temperature is just below freezing
or a light
frost is on the windshield which is generally removed by the wiper. However,
under such
conditions the windshield wiper blade can become stiff from the cold so as not
to follow the
curvature of the windshield, therefore giving poor visibility.
In the conventional windshield wiper, a flexible rubber strip is attached to
an articulated
wiper arm designated to accommodate to the curvature of the windshield. The
conventional
wiper arm of a personal transport vehicle typically includes a main support or
beam that is
pivotally linked to a mover arm, driven by a motor for reciprocating, pivotal
movement on a
motor shaft. A secondary wiper support or beam is pivotally linked to each end
of the main
beam, each secondary beam pivotally carrying a rubber strip holder in each end
of the
secondary beam. Tertiary wiper supports are also used. The rubber strip holder
is typically
arched and attaches with ends thereof to a metal rail, clamped about the
profiled backside of
the rubber strip. Thus, the conventional wiper arm mechanism typically
includes a plurality
of pivot joints and attachment points with the flexible rubber strip.
The ability of the wiper strip to accommodate to the windshield curvature in
order to clear the
glass surface from ice, snow, water is dependent on the flexibility of the
wiper blade.
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Typically the blade stiffens with cold, and a stiff blades does not conform to
the curvature of
the windshield.
Several prior art devices and methods have heretofore been proposed for
heating windshield
wipers. For example, U.S. Patent No. 5,426,814 relates to a heated windshield
wiper which
includes an elongated cylindrical body having a hollow interior and three (3)
wiping surfaces
which project from the body and extend longitudinally along the wiper. A
helical heating
element is concentrically positioned within the hollow interior of the wiper
and is
connectable to the vehicle battery to heat the entire outer circumference of
the wiper body
and the wiping surfaces to melt ice surrounding the wiper and on the
windshield. Alternate
embodiments include a fluid dispensing arrangement for dispensing fluid over
the heating
coil as well as an air expansion assembly for expanding the cylindrical body.
U.S. Patent No.
5,426,814 presents a relatively complicated blade assembly which is expensive
to
manufacture and maintain. Furthermore U.S. Patent No. 5,426,814 utilizes plugs
at the end
of the windshield wiper which connects to the heating elements; which can be
knocked off
during operation.
Furthermore U.S. Patent No. 5,787,543 relates to a heated windshield wiper
blade having a
heating element which comprises a flexible, spiraled resistance wire coiled
around stranded
fiberglass. This patent illustrates a complicated and expensive wiper blade
assembly. Also
the connections at either end of the rubber wiping surface can be displaced.
Another arrangement is shown in U.S. Patent No. 5,791,010 which relates to a
heated
windshield wiper having a heating element disposed above the blade. Any heat
from the
heating element will quickly dissipate into the atmosphere particularly if the
vehicle is driven
at more than moderate speed.
Also U.S. Patent No. 6,058,554 relates to a heated windshield wiper blade
which includes a
gel-filled core which extends the length of the windshield wiper blade which
gel-filled core
includes material which is both heat conducting and electrical conducting
while an electrical
conductor extends the length of the gel-filled core.
It is therefore an objection of this invention to provide for an improved
heated windshield
wiper blade.
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Disclosure of Invention
The above discussed disadvantages of the prior art are minimized by a
windshield wiper
blade that includes an electric heating element in the rubber wiper portion
thereof The
heating element is controlled by a switch on the dashboard and a temperature
sensor on he
wiper arm.
Other systems, methods, and advantages of the invention will be, or will
become, apparent to
one with skill in the art upon examination of the following figures and
detailed description. It
is intended that all such additional systems, methods, features and advantages
be included
within this description, be within the scope of the invention, and be
protected by the
following claims.
It is an aspect of this invention to provide a windshield wiper assembly
comprising a flexible
blade having two opposite ends thereof; a heating wire disposed within said
flexible blade
and having a connection to a power source intermediate said ends whereby said
heating wire
heats said flexible wire upon activation of said power source.
It is a further aspect of this invention to provide a windshield wiper
assembly for wiping the
outer surface of the windshield of a motor vehicle comprising a windshield
wiper assembly
for wiping said outer surface of said windshield, said assembly including a
support arm
adapted for rotational reciprocal movement across said windshield; wiper
support means
connected to said support arm; a flexible wiper blade mounted on said support
means, said
flexible wiper blade having a proximal end and a distal end; electrical
resistance heating wire
embedded in said flexible wiper blade extending from said distal end to said
proximal end;
power means for heating said electrical resistance heating wire; switch
between said power
means and said electrical heating wire; electrical power control means
disposed between said
switch and said electrical resistance heating wire for varying the power to
said electrical
resistance heating wire in response to temperature fluctuations.
It is yet another aspect of this invention to provide a method of heating a
flexible wiper blade
for a windshield comprising disposing electrical resistance wire within said
flexible wiper
blade between opposite ends thereof; connecting said electrical resistant wire
to said
electrical heating wire intermediate said ends of said flexible wiper blade;
providing a power
source to said electrical wire so as to heat said electrical resistance
heating wire in said
flexible wiper blade; varying the supply of power to said electrical
resistance heating wire
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through the use of a varistor disposed between said electrical resistance
heating wire and said
power source.
It is a further aspect of this invention to provide a method of heating a
flexible wiper blade
wherein said electrical resistance heating wire heats said body of said
flexible wiper blade so
as to maintain the flexibility of said blade.
Brief Description of Drawings
Fig. 1 is a perspective view of a heated windshield wiper embodying the
present invention.
Fig. 2 is a perspective view of a partial section view of detail A of Fig. 1.
Fig. 3 is a side view of the wiper blade.
Best Mode for Carrying Out the Invention
In the description which follows, like parts are marked throughout the
specification and the
drawings with the same respective reference numerals. The drawings are not
necessarily to
scale and in some instances proportions may be exaggerated in order to more
clearly depict
certain features of the invention.
Most vehicles have two wiper assemblies 10 on the windshield, and they may
have one on
the rear window and one on each headlight. The windshield wiper assembly 10
generally
comprises a wiper arm 20 pivotally connected at pivot 22 to a reciprocating
rotating motor
shaft assembly having a reciprocating rotating shaft 24 in a manner well know
to those
persons skilled in the art. The wiper arm 20 is connected to wiper support
means 30 by
means of pin receiving holes 32 in a manner well known to those persons
skilled in the art.
The wiper support means 30 carry the wiper blade 70. More particularly the
wiper support
means 30 comprises a main beam support or linkage 34 having ends 36 and 38
thereof
Second beam supports or cradle blade carrier 40 and 42 are connected to the
ends 36 and 38
of main beam 34, while third beam supports or linkages 44 and 46 are each
connected to
second support beams 40 and 42 respectively all in a manner well known to
those persons
skilled in the art.
In the wiper assembly 10 shown in Figs. 1, 2, and 3, the wiper assembly 10 has
up to six (6)
parts called pressure points or claws 50, 52, 54, 56, 58 and 60. The claws 50,
52, 54, 56, 58
and 60 distribute pressure from the wiper support means 30 along the back of
the blade 70.
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Generally speaking this is known as a balance beam with a suspension system.
The claws 50,
52, 54, 56, 58 and 60 keep the blade flexed against the windshield to
distribute even pressure
to clean the glass along the blade 70.
The wiper blade 70 comprises a flexible or rubber portion 72 and includes
exterior metal
strips 74 and 76 generally known as a blade frame within a slot 78 and 80
along the length of
the rubber member 72 as shown. The blade frame includes cut-outs (not shown)
which are
adapted to receive the claws 50, 52, 54, 56, 58 and 60 respectively all in a
manner well
known to those persons skilled in the art.
The standard two windshield wipers are generally operated as a single-motor,
tandem scheme
with one wiper on the driver's side in one position near the middle of the
windshield that
moves across the passengers view. The wiper arms 20 are secured to pivots 22
connected to
the reciprocating rotating shaft 24 so as to move the wiper assembly 10.
A slender spring linkage (not shown) ties the pivot 22 to the reciprocating,
rotating shaft 24
so as to return the wiper support 10 to its resting or parked position,
hugging the wiper close
to the windshield and keep it attached to the car if the links are damaged.
The motor vehicle has a power source such as a battery or the like.
Alternatively, the power
source may be electrically connected to the ignition system to avoid draining
the battery.
The wiper blade 70 is mounted to the support means 30 and has a proximal end
90 located
near the rotating shafts 24 as well as a distal end 92. An electrical
resistance heating wire 96
is embedded in the flexible wiper blade 70 and extends from the proximal end
90 to the distal
end 92 as shown.
In one embodiment the heating element 96 comprises a nickel chromium wire
which is
heated by means of a current which is carried by wire 100 to a dash mounted on-
off switch
102 that is connected either directly to the battery or more preferably to the
ignition system
(not shown) to avoid battery drain in the event that the wiper heater switch
102 is left on
unintentionally when the engine is shut of The power supply from the on-off
switch 102
flows to a thermal varistor 104 which acts both as a resistor and a
thermostat. The
thermostatic portion of the varistor 104 will allow the flow of power to
increase as the outside
temperature decreases and vice versa. The increased flow of power will
increase the
temperature of the internal heating element while a decrease of power will
decrease the
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temperature of the element. The varistor also has the ability to shut off the
power flow
should the air temperature rise above a given set point.
The power from the varistor 104 flows to a connection plug106 which has two
parts that are
separable and connectable to each other. The wire 100 enters the support means
in the center
and runs internally in the rubber portion 72 as shown in Fig. 3. More
particularly the wire
100 enters the blade in the center and then runs to one end and then loops
back to the other
and then back to the center. Accordingly there are no plugs at the ends of the
wiper blades to
fall off.
In one embodiment the heating element is made of Ni-chrome wire which is an
alloy of
nickel and chromium. In one embodiment the diameter of the nickel chromium
wire can vary
according to the length of the blade. There is no need for any type of coating
around the
nickel chromium heating element.
The thermostatic portion of the varistor 104 includes a temperature sensor to
sense the
temperature and electrically connect or disconnect the flow of power to the
heating element.
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