Note: Descriptions are shown in the official language in which they were submitted.
~ 21 9924
0
A Wiper Assembly
This invention relates to wiper assemblies.
Virtually all vehicles.today (cars, trucks, trains, airplanes,
boats etc) incorporate one or more windshield wipers which can be
deactivated at any time by a driver to sweep repeatedly across an
exterior surface of the windshield. A rubber or plastic wiper
blade of each wiper assembly engages the exterior surface to clear
debris from that portion of the windshield generally in front of
1,0 the driver to maintain unimpaired visibility. Debris left to
build up on the windshield impairs visibility for the driver and if
permitted to build up anywhere on the wiper assembly can also
reduce wiping efficiency. Maintaining good visibility for the
driver lessens the chances of the vehicle becoming involved in an
accident and hence increases the safety level for all occupants.
The type of debris which Can accumulate depends on the
geographical location and season. In particular, in parts of the
world where winter weather is severe, snow and ice build up on
wiper blades is a common experience. In particularly extreme
weaaher conditions, it is not uncommon for snow or ice to freeze to
a windshield wiper arm and/or wiper blade. While allowing for
movement of the blade across the windshield, such frozen debris may
seriously reduce the cleanirng- action of the blade on the windshield
surface. Such freezing may occur while a vehicle is being driven
or when stationary. Also, it is common for lumps of ice or snow
to become lodged under a wiper blade during use so as to be carried
with the blade on its wiping movement. This situation may occur
~ ~ 21 99 2 4~
if the blade in moving across the windshield surface is caused to
ride onto a mass of ice or snow and move it from a stationary
location upon the windshield.
As long as an ice or snow mass remains lodged the efficiency
of the wiper blade is severely reduced as a significant portion or
all of the wiper blade can no longer engage the exterior surface of
the windshield. The thickness of any mass of ice or snow may have
a bearing on the wiping efficiency especially if the mass extends
along a significant length of the blade. Ice lumps as small as
one millimeter if lodged can cause the wiper to experience reduced
efficiency. Snow and/or ice formation anywhere on the windshield
wiper assembly may contribute to reducing w~.pir~g efficiency also by
raising sections of the blade off the windshield.
A driver of a vehicle when experiencing any of the problems
discussed above generally has two options. The first and safest
option is to stop the vehicle and, even in extremely cold
conditions, exit the vehicle to manually break away the ice or snow
frozen to or trapped beneath the wiper blade. This is not always
convenient and is certainly not possible for pilots and train
operators. Even when driving a road vehicle there are times when
stopping to remove debris from a windshield is impossible due to
inherent danger. For instance, bridges or certain roadways have
little or no shoulder area and when busy with traffic, a driver may
not stop safely. Even when there is room to stop by the roadside,
it may not be prudent to do so a$ personal safety rnay be at risk if
the driver leaves the vehicle or if his parked position may present
2
2~ 99240
a dxiving hazard to other vehicles.
A common although unrecommended solution for many drivers is
to open a window and manually attempt to grasp a windshield wiper
as it travels within extended reach of the driver. In reaching
the wiper, the driver attempts to lift it momentarily from the
windshield in the hope that the debris will become dislodged.
Needless to say this i.s an extremely unsafe practice and, in many
cases, such as for larger vehicles, e.g. trains and airplanes, is
simply not an option:
A further problem concerns the coating of a wa.ndshield wiper
assembly with ice or snow when the wipex asembly is in the parked
position during storm conditions. The thickness of the ice or
snaw may be such as to trap the wiper assembly in the parked
position and thus prevent its operation when the operating motor i.s
energized. It can be azz extremely tedious and unpleasant
operation for a driver to need to free the wiper manually from the
parked position in winter conditions. To ease this problem, some
car manufacturers incorporate heating e~.ements in windshield glass .
The elements function to heat windshields in a manner similar to
that of present day electrical rear window defrosters. This
solution is not only expensive and extremely slow in effective
operation, it cannot dislodge or melt ice or snow while the wiper
assembly is in operation. Furthermore, windshield heating
elements are ineffective in releasing wipers from ice or snow when
in their parked positions if the wiper blades are not in engagement
with the windshields.
3
CA 02199240 2001-02-08
Other solutions, such as in U.S.Patent No. 5,325,561, issued
to Kotlar, teach electrically heating various portions of a wiper
blade to melt away snow and ice. Although this solution is
somewhat effective when the wipers are in operation, it is an
extremely slow operation. This solution can also be very
expensive for the owner of the vehicle as wiper blades wear away
and should be replaced regularly. Wiper blades of the type taught
in the above patent would incorporate an integral electrical
heating element thereby drastically increasing the cost of
replacement blades.
In addition, headlights on some cars incorporate a small wiper
arrangement to clean the exterior glass surfaces of the headlights.
Headlight wipers may suffer severe ice buildup in winter climates
and very often cannot be operated as they become frozen in
position. Their proximity to the ground and front end location
places them directly in the path of snow, slush and ice raised by
passing vehicles or vehicles in front.
Summary of the invention.
The invention seeks to provide a wiper assembly and a
combination of wiper assembly and light transmitting screen member
which seek to minimize the above problems.
According to the present invention, there is provided a wiper
assembly comprising a wiper arm having means for releasably holding
a wiper blade, resilient means connected to the wiper arm for
urging the wiper arm towards a surface to be cleaned in use, and a
vibration generating means including a driveably moveable mass
4
CA 02199240 2001-02-08
disposed upon the wiper arm and driveable to provide a
directionally changing inertial load to the wiper arm for imparting
vibrational movement to the wiper arm to cause at least parts of
the wiper blade to move repeatedly out of and into contact with the
surface to be cleaned for effecting release of the frozen mass when
this is trapped beneath the wiper blade, the driveably moveablemass
being driveably moveable independently of the movement of the wiper
arm.
The invention also includes according to a further aspect, a
combination of wiper assembly as defined above and a light
transmitting screen member. In this further aspect the screen
member has a surface to be cleaned and is carried in a supporting
body and the wiper arm of the wiper assembly is mounted to the
supporting body. Driving means is provided to move the wiper arm
in outgoing and return directions of travel across the surface to
be cleaned.
In the above combination according to the invention, the light
transmitting screen member is considered to include vehicle
windshields such as cars, trucks and buses. It is also considered
to include a window of an aircraft, ship or train, a protective
glass of a headlight and the glass surface found on a side mirror
of a truck. Any type of transport may thus benefit from the
invention, i.e. land, sea or air vehicles.
The resilient means is normally in the form of a tension
spring which applies the wiper blade to the light transmitting
screen member with a small force, perhaps of the order of 12 pounds
5
CA 02199240 2001-02-08
or less and which needs to be overcome by the vibration generating
means in effecting the vibrational movement.
Constructions according to the above invention dislodge ice or
snow debris trapped between the wiper blade and the light
transmitting screen member. These structures may possibly cause
the wiper blade to return to the surface of the light transmitting
screen member with an impact force sufficient to shatter ice and
snow accummulated on and frozenly adhered to the wiper blade or
wiper arm.
The invention also includes a wiper assembly comprising a
wiper arm having means for holding a wiper blade, resilient means
connected to the wiper arm for urging the wiper arm towards a
surface to be cleaned in use, a vibration generating means mounted
on the wiper arm and operable for imparting vibrational movement to
the wiper arm so as to cause at least parts of the wiper blade to
move repeatedly out of and into contact with the surface to be
cleaned for effecting release of a frozen mass when this is trapped
beneath the wiper blade, and means for operating the vibration
generating means, the operating means having an energizing mode and
a non-energizing mode, and in the energizing mode the operating
means operates the vibration generating means to continuously
impart vibrational movement to the wiper arm.
In addition, the invention includes a combination of wiper
assembly as defined in the last preceding paragraph, and a light
transmitting screen member. The light transmitting screen member
has a surface to be cleaned and is carried in a supporting body and
6
CA 02199240 2001-02-08
the wiper arm of the wiper assembly is moveably mounted to the
supporting body. Driving means is provided to move the wiper arm
in outgoing and return directions of travel across the surface to
be cleaned.
Description of Preferred Embodiments.
Embodiments of the invention will now be described, by way of
example, with reference to the accompanying drawings, in which:-
Figure 1 is an isometric front elevational view of part of a
vehicle and incorporating a wiper assembly according to a first
embodiment;
Figure 2 is a cross-sectional view taken along line 2-2 in
Figure 1 of part of the vehicle and showing the wiper assembly in
side elevation;
Figure 3 is a front elevational view of the windshield of the
vehicle in Figure 1 and to a larger scale to show greater detail;
Figure 4 is a view similar to Figure 2 and to a larger scale
to show the wiper assembly in a first position during use;
Figure 5 is a view similar to Figure 4 and showing the wiper
assembly in a second position of use;
Figure 6 is a view similar to Figure 3 and shows a
modification of the first embodiment;
Figure 7 is a front elevational view of part of a wiper
assembly according to a second embodiment;
Figure 8 is a cross-sectional view taken along line 8-8
in Figure 7 and showing the wiper assembly of the second embodiment
in one position upon a windshield of a vehicle;
7
CA 02199240 2001-02-08
Figure 9 is a view similar to Figure 8 showing the wiper
assembly of the second embodiment in another position relative to
the windshield;
Figure 10 is a view similar to Figure 7 of a modification of
the second embodiment;
Figures 11 and 12 are views similar to Figures 8 and 9 of a
third embodiment of the invention;
Figure 13 is a cross-sectional view taken along line 13-13 in
Figure 12 of the third embodiment;
Figures 14, 15 and 16 represent a fourth embodiment and are
views, respectively, similar to Figures 7, 8 and 9;
Figure 17 is a view similar to Figure 16 and showing only part
of the windshield wiper assembly of a modification of the fourth
embodiment;
Figure 18 is a wiper assembly according to a fifth embodiment
and showing a wiper blade held closely against a windshield;
Figure 18a is a view in the direction of arrow 18a in Figure
18;
Figure 19 is a view similar to Figure 18 and showing the blade
moved away from the windshield at both ends;
Figure 20 is a view similar to Figure 4, but to a larger
scale, and shows part of a windshield wiper assembly according to
a sixth embodiment;
Figure 20a is a cross-sectional view taken along line 20a-20a
in Figure 20 and to a larger scale;
Figure 20b is a view in the same direction as Figure 20 to
8
CA 02199240 2001-02-08
show flexing of a wiper blade in use of the sixth embodiment;
Figure 21 is a view similar to Figure 20a of a modification of
the sixth embodiment;
Figure 22 is a view similar to Figure 20 of a seventh
embodiment; and
Figure 23 is an isometric view partly in cross-section showing
a combination of wiper assembly and windshield according to an
eighth embodiment.
As shown in Figure 1, a vehicle has a body 10 with a
windshield 12 and has attached thereto a windshield wiper assembly
14 according to a first embodiment. As will be seen from Figure
1, only one windshield wiper assembly is shown. This is for
convenience only and it should be understood that as with other and
more conventional vehicles two windshield wipers are actually used,
i.e. one for each of the left and right sides of the windshield.
As shown by Figure 1, and more particularly by Figure 3, the wiper
assembly 14 is conventional in that it has a wiper arm 16 pivotally
attached at one end to a short oscillatable shaft 18 which extends
through a part of the body (Figure 2) directly beneath the
windshield 12. In known manner the arm 16 may be oscillated from
side to side upon the outside surface of the windshield for the
express purpose of cleaning the windshield during adverse weather
conditions. Also, conventionally, the wiper arm 16 carries, about
a mounting pin 20, a wiper blade 22 which is to be held against the
9
i
~ X2199240
windshield with a surface engaging pressure to perform a cleaning
operation. To provide the surface engaging pressure, means is
provided for urging the wiper arm towards the windshield. The
urging means comprises in the embodiment, a tension spring 24
(Fi.gure 4) which extends partly along the length of the arm 16 from
the shaft 18. The action is such that any manual effort to raise
the arm 16 away from the windshield is resisted by the tension
spring 24 which upon the arm being released, immediately forces the
blade 22 to return into its normal position in engagement with the
surface of the windshield.
The invention differs from conventional constructions and as
illustrated, for instance, by the first embodiment, in that an
urgEing means is also provided to move the arm 16 in a direction
away from the windshield and against the influence of the spring
24. This latter urging means is operable to at least lessen the
surface engaging pressure of the blade 22 upon the windshield and
preferably, as in the embodiment, to move the blade 22 completely
away from the windshield for a specific time period. Lessening of
the surface engaging pressure is intended to decrease any grip that
the blade may have upon any debris in the form of lumps of ice or
snow which have become lodged under the wiper blade 22 and are
being carried with the blade on its wiping movement across the
windshield. Such lumps ,if remaining in place seriously impede
contact of the blade upon the windshie~.d and, as a result,
seriously reduce the cleaning action of the blade. Lessening of
the surface engaging pressure permits such debris to fall from
,~, X2199240
between the blade and the windshield. Preferably, however, the
movement away from the windshield is complete such that debris
being carried on its oscillating movement by the blade 22 is
released thereby clearing the windshield of the debris.
In this embodiment the means for urging the wiper aim away
from the windshield comprises an electrically powered means in the
form of two magnets 26 and 28 (Figures 3, 4 and 5). The magnet 26
is securely mounted upon the arm 16 at a position towards its
pivotted end and out of the line of swept area of the wiper blade
22. However the magnet 26 could. also be disposed further along
the arm so as to lie within the swept area. The magnet 26 is
mounted on the arm 16 ~o as to be directed towards the windshield
12, as shown particularly in Figure 4, and is held in place in the
embodiment by a holding means which may be in the form of a strap
30 extending around the arm 16 so as to hold the magnet 26 against
the arm and with the magnet projecting through an orifice in the
strap towards the windshield. The other magnet 28 is mounted by
epoxy, for example, on the inside surface of the windshield in a
position such that during oscillation of the wiper arm 16 across
the windshield, the magnet 26 passes directly over the magnet 28.
One of the magnets 2,6 and 28 is an electromagnet, although
both may be electromagnets. In the embodiment the magnet 28 is a
permanent magnet and the magnet 26 is an electromagnet and is
energized by wires 32 extending down the arm and forming part of
the circuitry of the vehicle, the wires connected to a manually
operable switch 34. Upon energization of the magnet 26, a
11
~~ 9924p
repelling force i.s generated between the two magnets when the
magnets 26, 28 are directly over one another such that the
repelling force acts against the wiper arm 16 to move it away from
the windshield. The spring 24 offers only light force to move the
arm 16 against the windshield i_e. to the order of a few pounds
only. The repelling force of the two magnets 26.and 28 may be
made sufficient to move the arm 16 so that the wiper blade 22 is
forced to lose contact with the windshield.
Tn use, the wiper arm 16 is actuated in conventional manner to
perform its oscillating movement so that the blade may clean the
windshield in normal fashion. However, when debris, such as a
mass of ice or scow, is caught between the blade and the windsh~.eld
and carried by the blade across the windshield, the oscillating
movement of the blade will not release sur_h dP'(r;s_ HPnr~P_ ac
_ _ ________ _____ _______ _______,
shown by Figure 2, the arm 16 is moving across the windshield in
the full outlir~e position with the blade normally in contact with
the windshield. Should debris be required to be removed from
bsneath the wiper blade 22 then.the magnet 26 is energized by the
driver from within the vehicle. As soon as the magnet-26 passes
directly over the magnet 28 a repelling force is generated thereby
forcing the arm 16 and blade 22 into the ch~indotted position
(Figure 2) until the magnet 26 has passed beyond the magnet 28 at
which point the arm 16 returns to its full outline positon. As
may be seen, and as is more clearly shown in Figures 4 and 5, the
movement to the chaindotted position in Figure 2 and as represented
in greater detail by Figure 5, provides sufficient gap between the
12
~~ X9240
blade 22 and the windshield to enable the debris either to fall
away from or be blown away from the blade 22 thereby clearing the
windshield of obstruction. For debris which refuses to fall away
from, or be blown away from under the blade 22, the wiper blade,
whale in the raised chaindotted position (Figure 2) will usually
travel over and beyond the debris before returning to its normal
position. This action generally results in the debris being
cleared from the windshield on the next or subsequent pass of the
wiper blade as the blade along its complete length is then engaging
the windshield. In addition to this, when the blade 22 returns to
the windsh~.eld, (full outlined position in Figure 2 and as shown in
Figure 4), it may return with sufficient force as to shatter
accummulations of ice or snow which are frozen on the wiper
assembly itself. This shattering action will of course depend
upon the hardness and concentration of the ice or snow and upon the
impact force.
As may be seen, therefore, the magnets 26 and 28 are operable
to clear masses or accummuiations of ice and snow which ire either
frozen to the wiper assembly or are carried by the wiper blade
across the windshield surface. Movement of the wiper blade away
from the windshield has a secondary advantage in that it allows
other materials, e.g. leaves or paper, to fall from the windshield.
Preferably, an electronic switch means is provided (not shown) to
activate the electromagnet 26 which only requires a single
momentary action by the user. The electronic switch means would
iriclude an electronic holding circuit capable of keeping the
13
~2~~~24~
electromagnet 26 energized for a suffic~.ent period of time to
guarantee the required positioning of the magnets 26, 28 to
generate the repelling force, regardless of where in the wiper
travel the switch is activated. These advantages also apply to
further embodiments and modifications thereof now to be described.
In a modification of the first embodiment as shown by Figure
6, a plurality of permanent magnets 28 are provided on the inside
surface of the windshield. These magnets are positioned in spaced
locations around an arc which is to be swept by the electromagnet
26. In use of the modification shown in Figure 6, with the
electromagnet 26 energized, the blade 22 is held away from the
windshield for an extended period, l . e. over the full length of the
sweep of the blade across the windshield. This provides longer
periods of time than is possible in the use of the first
embodiment, for enabling masses of ice or snow to be removed from
beneath the wiper blade, or from frozen adherence to the wiper
assembly.
In an alternative circuitry arrangement for the modification
of Figure 6, one or ail of the magnets 28 ale also electrdmagnets.
This structure enables the blade 16 to be moved outwards from the
windshield at any chosen location during its sweep dependent upon
which of the electromagnets 28 is. energized for this purpose.
In further embodiments now to be described, features of
similar construction to those described in the first embodiment
will be referred to by use of the same reference numbers as in the
first embodiment without further discussion.
14
'~ ~9 2 ~0
In a second embodiment as shown in Figures 7, 8 and 9, the
means for urging the wiper arm and thus the blade away from the
windshield 12 is again an electrically powered means and comprises
a solenoid actuator 40 having an axially moveable plunger core 42
within a cylindrical housing 44. Means are provided for mounting
the solenoid actuator upon the wiper arm 16 with the plunger core
42 having an operative end 46 extending from the solenoid housing
44 and towards the windshield 12. The means for securing the
solenoid actuator to the arm comprises a protective rubber or
plastic molded surround 48 which is shaped intimately around the
cylinder 44 and extends inwardly of the cylinder adjacent the end
46 of the solenoid to surround the plunger core 42 of the solenoid
while allowing for its sliding axial movement. The surround 48
has a mounting portion 52 by which it is mounted to the wiper arm
1.6 as shown in Figures 7 to 9. This mounting portion (which
extends in a direction normal to the axis of the solenoid actuator)
may be cylindrical in molded form so ~s to be received upon the
arm 16 by its sliding reception down the arm. Alternatively (not
shown) the mounting portion 52 may be split along its length to be
wrapped around the arm 16. In either case, the surround 48 is
secured in position by a holding means comprising two metal clamps
54 surrounding two end portions of the mounting portion 52 and
tightened to grip the mounting portion upon the arm 16.
Alternatively, other holding. means may be provided such as
resilient clips which are sprung resiliently into position around
the mounting portion 52. ~s a result, and as shown particularly
,. ~ ~~~ ~9~0
by Figure 7 when the solenoid actuator 40 is in position a.t is
disposed towards one side of the wiper arm 16.
In use of the second embodiment, the wiper arm 16 is moved in
oscillatory fashion across the windshield as in the first
embodiment while occupying a position relative to the windshield as
shown in full outline in Figure 2 and by Figure 8, i.e. with the
wiper arm in contact with the windshield with a surface engaging
preasure. Should it be required to remove a mass of ice or snow
from beneath the wiper blade it is merely necessary to actuate the
solenoid actuator which is connected to the circuitry of the
vehicle by conductors 32 as in the first embodiment. Solenoid
actuation by driver operation of the switch, results in the
movement of the plunger core 42 outwardly and into contact with the
windshield. As a result of this, the action of the spring 24 to
hold the wiper arm in the position of Figure 8 is overcome and the
wiper arm is caused to move outwardly to the position of Figure 9.
This moves the wiper arm in a direction away from the windshield
and positions the assembly somewhat as shown in the dotted position
for the assembly in Figure 2. Upon the debris being released from
beneath the wiper arm the solenoid actuator is de-energized by the
driver to cause the wiper arm to return to its Figure 8 position.
Dependent upon the solenoid characteristics and its power
relationship to the spring 24, it is possible that the wiper arm
may return to the windshield at sufficient speed to create an
impact load to break any ice or snow accummulation frozen to the
wiper arm or wiper blade. The usefulness of the wiper assembly in
16
2~ 9~24a
this respect and in other embodiments, depends not only on the
return speed and impact force of the wiper assembly as mentioned
above but also on the accummulation, hardness and other
characteristics of the snow or ice upon the wiper assembly.
depending on the speed with which the plunger core 42 moves
outwardly and into contact with the windshield, a cushioning tip
(not shown) placed over the operative end 46 may be required to
prevent damage to the windshield. t
In a modification of the second embodiment as shown by Figure
10, a solenoid actuator 40 is mounted in a different manner upon
the wiper arm. In this modified construction the wiper arm 16a is
of slightly different construction from the arm 16 of previous
embodiments in that it has a local wider~ed area 56 provided
with a central aperture 58 for receiving the solenpid actuator 40
through the aperture. The end 46 of the plunger core is directed
towards the windshield as described in the second embodiment. The
solenoid actuator is mounted within a molded plastic or rubber
surround 60 which has integrally formed therewith a metal or hard
plastic bracket 62 atone end. This bracket 62 is attached to the
wiper arm 16a by rivets 64 although other holding means such as
shrews or nut and bolt assemblies may be used.
In a third embodiment as shown in Figures 11, 12 and 23, in a
wiper assembly, a means 74 for urging the wiper arm away from the
windshield comprises a solenoid actuator 72 mounted within, a
pra~tective surround 74, the surround being mounted upon the wiper
arm. 16 in a manxier simzlar to that of the second embodiment and
17
~ ~ 9940
also receiving the solenoid actuator in like manner. The solenoid
actuator 72 has a projecting plunger core end 76 which faces
towards the windshield 12. Positioned upon the windshield 12 is a
rigid ramp 78 which is localized in position and disposed along the
arc of movement of the plunger core end 76. In normal operation
(Fi.gure 11 and full outline in Figure 13) the plunger core end 76
is in a retracted position so that as the wiper arm oscillates over
the windshield, the end 76 is spaced from the ramp 78 as it passes
over it. However, should it be required to remove a mass of ice or
snaw moving with and positioned beneath the wiper blade, thin the
solenoid is actuated by driver operation of the switch to force the
end 76 outwards towards the windshield ( chaindotted position 76a in
Figure 13). Upon the end 76 reaching the ramp, and as shown in
the chaindotted position 76b in Figure 23, the end 76 is caused to
ride over the ramp thereby forcing the wiper arm into a position
away from the windshield, e.g. as shown in Figure 12 i.e. in the
cha:indotted position in Figure 2, thereby enabling masses of ice or
snow caught between the wiper arm and the windshield to be
released. To cause the outward movement of the wiper arm, either
the ramp 78, the plunger core 76 or each of them as shown in Figure
13 has two inclined side surface reg~.ons to enable the plunger core
end 76 to ride over the ramp while being directed outwardly. It
is considered that each ir~clined surface may lie at a preferred
angle of between 15 and 45 degrees to the plane of the windshield
at the ramp position to achieve the desired result.
In a fourth embodiment as shown by Figures 14, 15 and 16, a
18
2'~ ~9~0
means 80 for urging the wiper arm away from the windshield 12
comprises an electrically powered means having a DC motor 82 held
in position between the wiper arm and the windshield by a U-shaped
holding bracket 84 which extends around the housing of the motor
and has two ends 86 which are attached to' the underside of the
wiper arm by srewthreaded means 88 or rivets as required. The
motor 82 is disposed with its axis of rothtion extending generally
in the direction of oscillating movement of the wiper arm. The
means 8D a~.so includes an edge cam 90 which is secured to one end
of the rotatable mass of the motor 82 and outwardly from the motor
so as to be exppsed. As will be seen from Figure 15, the cam edge
surface of the cam 90 is shaped so that with the arm 16 moving
along its normal path, the cam is clear of the windshield 12.
However, should it be required to remove ice or snow from beneath
1~ and moving with the wiper arm, then the motor 82 is energized by
driver operation of the switch thereby rotating the cam 90 in the
direction of the arrows in Figures 15 and 16. The edge profile of
the cam is such that the cam rotates into engagement with the
windshield 12 and has suff~.cient lift as illustrated by Figure 16
to raise the arm 16 away from the windshield, e.g. as shown in
chaindotted outline in Figure 2, with the wiper blade removed from
the windshield. As in previous embodiments, this action results
in ice or snow trapped by tyre wiper arm being permitted to fall or
be blown away out of contact with the arm. It will be noticed
that a lift portion 92 of the cam 90 ends abruptly at an inwardly
extending edge face 94. Upon the cam moving past the position
19
~ 92~ 99240
where the lift surface engages the windshield, the wiper arm is
caused to return towards the windshield with an impact force under
the influence of the spring 24. This may have the effect of
shattering ice or snow which has settled and has frozen to the
wiper assembly, and comments regarding the usefulness of this
action for snow or ice removal are similar to those contained in
the second embodiment.
It is interesting to note in the fourth embodiment that the
motor 82 may be energized over any desired period of time. Thus
20 the cam 90 will continue rotation during this time period and
causes repeated cycles of movement of the arm away from the
windshield. This action may be particularly useful for ice or snow
removal and will take place progressively along the sweep of the
arm over the windshield.
In modifications of the fourth embodiment, a cam may have a
different edge profile to provide a different result. For
instance as shown in the modification by Figure 17, a symmetrically
arranged elliptical form of cam surface is provided upon a cam 98.
This shape of cam will of course result in movement of the wiper
arm 16 away from the windshield twice for each motor revolution.
The effectiveness of the impact force upon the windshield for
ice and snow removal in the fourth embodiment and the modification
thereof, depends upon the shape of the cam surface and also may
depend upon the rotational speed of the motor.
In a fifth embodiment as shown in Figures 18, 18a and 19, a
wiper assembly has means 100 for urging an end p~r~tion of a wiper
,~ ~ !~ 2'~ ~~ ~ 40
blade away from the windshield 12. The means 100 actually operates
to move either end portion or both end portions of the wiper blade
away from the windshield as desired dependent upon the position of
location of debris under the wiper blade.
The means 100 comprises two solenoid actuators 102 secured to
a wiper blade carrier 104 for the wiper blade 22, one solenoid
actuator on each side of the mounting pin 20 of the wiper blade
carrier to the wiper arm 16. The solenoid actuators face in
opposite directions along the wiper arm carrier 104, (see Figure
18a particularly) with each solenoid actuator having a plunger core
with an end 108 projecting from the cylindrical housing 110 of the
actuator 102 towards the closer free end of the wiper blade
carrier. Each of the plunger core ends 108 is connected by a
rigid link 112 to the closer free end region of the wiper blade
carrier 104, the link 112 having a pivotal connection at each end.
Upon energization of each of the actuators 102, the associated
plunger core moves in a direction away from the closer free end of
the wiper arm carrier thereby drawing the end 108 and the link 112
in 'the same direction. This effects a shortening of the distance
between the pivotal position of the link 112 to the carrier 104 and
the housing 110 of the solenoid actuator. As a result of this,
the carrier arm and thus the wiper blade at that end of the wiper
blade are caused to move outwards from the windshield thereby
providing a clearance between the blade and the windshield such as
is shown at either end of the structure in Figure 19. At this
stage, only the central rec,~~:.p~a of the wiper blade actually touches
2x
~ ~~ z ~o
the windshield. The clearance between each end portion of the
wiper arm and the windshield enables loosening of ice or snow
debris carried beneath the wiper blade at the end portion. A
subsequent shattering effect may occur when the solenoid actuators
de-energize and the ends of the wiper blade return against the
windshield with impact. --
In each of a sixth and seventh embodiments to be described, a
wiper arm and thus a wiper blade are subjected to vibration which
produces a recurrent impact on the windshield with. sufficient force
to dislodge or shatter ice or snow when this is trapped between the
blade and the windshield or is frozen to the wiper arm or blade.
In these particular embodiments, as will be Seen, a moveable mass
is driven for the purpose of creating this vibration. Thus, the
driven .speed and size of the moveable mass, together with its
manner of application and distance from the pivotal axis of the
wiper arm are all instrumental. in deciding the frequency of
vibration of the wiper arm and wiper blade. This frequency may
also be partly governed, by the natural frequency of oscillation and
stiffness of the wiper arm and wiper blade assembly and is also
largely influenced by the size and design of the assembly and the
force of the tension spring which normally urges the wiper blade
against the windshield. Further, ambient temperature conditions
may play a role as they have axe influence upon the stiffness of the
wiper blade material and also upon, the tension spring. It follows
that many parameters are involved in producing the desired force to
dislodge or shatter ice and snow tapped and carried by the wiper
22
.' ~ ~~9 ~ 40
blade or frozen to the wiper assembly. Hence, the size of the
mass which is needed to produce the desired result is dependent
upon the above parameters for any particular wiper assembly
structure. Indeed, the seed of movement of the driven moveable
mass and the size of the mass may be such that the resultant
frequency and amplitude of vibration of the wiper blade are
entirely erratic. Hence, the resultant frequency and amplitude
may differ from one vibration to another dependent upon whether the
moving mass is working in sympathy with, or is acting against, the
direction of vibration caused in the wiper blade at any instant.
It is clear from studies which have been conducted that the
vibrational force produced should not only provide visible
vibration to the naked eye of the wiper blade assembly, but also
should cause at least parts of the wiper blade to move repeatedly
into and out of contact with the surface of the windshield when no
ice or snow is present. The vibrational force operating in
conjunction with springs mounting the wiper blade to the wiper arm
may, for instance, at specific moments in time, cause the end
regions of the wiper blade to move out of contact with the
windshield surface in repeated fashion. At other specific
moments, lengths of the wiper blade between the end regions may
move away from the windshield surface with lengths of the wiper
blade towards or at the end regions at that time in contact with
the windshield surface. The vibrational force produced and which
cau;~es the blade to move into and out of contact with the
windshield as just discussed, results in movement of the blade into
23
. ~~ s
and out of contact with ice or snow when this is trapped by, or is
moving with, the wiper blade, either to release the mass of ice or
snow as a single entity or to give repeated blows to shatter the
mass, thus resulting in its dispersion.
While the term "amplitude" is used in this discussion, the
term is used rather loosely in that it is normally used to refer to
the extent of swing of a vibrating body on each side of a mean
position. However, in constructions in the sixth and seventh
embodiments, there is no mean position as the wiper blade is forced
by the tension spring on the arm against the windshield thereby
deadening or damping out "amplitude" in its normal sense. The
term "amplitude" is thus used in this specification to refer to the
extent of lateral movement of the wiper arm and blade assembly over
the dampening effect of the tension spring.
From the above, it follows that with regard to the employment
of vibrational movement under the instrumentation of a driven
moveable mass, the invention as exemplified in the sixth and
seventh embodiments is concerned, with the generation of vibrational
characteristics which is in combination with the momentum of the
moving mass to produce sufficient vibrational force to release
and,~or shatter a mass of ice or snow beneath the wiper blade or
shatter a mass frozen to the blade or to the wiper arm. It is in
this realization that the inventive concept lies with these
embodiments.
In a sixth embodiment as shown in Figure 20, a means 120 is
provided for imparting a vibrational movement to the wiper arm and
24
~ a ~92~0
thus to the wiper blade during a sweeping action of the wiper arm
or in a stationary position. The means 120 comprises a DC electric
motor 122 which is positioned on the side of the wiper arm remote
from the blade and close to the pivot position of the wiper blade.
The driven shaft 124 of the motor carries a mass 126 which is
eccentrically carried in relation to the rotational axis of the
motor. The motor 122 is rigidly held within a surrounding
environmentally protective casing 129 of rubber or plastic and
which also surrounds the mass while providing clearance to allow
for eccentric rotation of the mass. Surrounding the casing and
the arm 16 is a strong metal strap 127 to secure the casing and the
means 120 in position.
The mass 126 is offset in such a way as to cause the wiper
arm 16 to vibrate in a direction towards and away from the
windshield, as shown by the arrows 128, when the motor 222 is
energized by the driver by operation of switch 34 within the
vehicle. As vibrational movement occurs during oscillation of
the wiper arm, any mass of ice or snow trapped beneath and moving
witlh the wiper blade is either ejected to cause its dispersion or
any ice or snow frozen to the wiper assembly is shattered. The
momentum of the eccentrically rotating mass in combination with the
vibrational characteristics of the wiper arm and blade assembly
produces a vigorous vibrational force which deflects and deforms
the wiper blade sufficient to raise parts of the blade repeatedly
out of contact with the windshield. The repeated movement into and
out of contact with the windshield permits and encourages the
~~~99240
dislodgement of ice or snow when trapped beneath the wiper blade
and this is assisted by the repeated hammer-like blows of the blade
upon the ice or snow as the parts of the blade return towards the
windshield surface. It is found that such masses of ice or snow
are dispersed within a few seconds, e.g. 1 to 10 seconds.
Further, the vibrational force provides a sufficiently vigorous
vibration of the wiper assembly as to shatter ice and snow frozen
to -the assembly. Such shattering is also assisted by a flexing of
the wiper blade during its vibrational movement. The blade may
flex so that in some flexed positions, end parts of the blade move
out of contact with the windshield while other parts remain in
contact therewith. In other flexed positions, the end parts
remain in contact with the windshield while other parts are flexed
outwards away from it. This is illustrated diagrammatically in
Figure 20b wherein -the windshield engaging edge of the wiper blade
22 is shown in one flexed position 23a with end_parts raised away
frorn the windshield as shown by arrows at the blade ends and in
another flexed position 23b with more central parts away from the
windshield (arrows in blade center). In the latter position the
end parts are in contact with the windshield. In Figure 20b,
other parts of the wiper assembly are omitted for clarity.
The rotational speed of the motor together with the size and
eccentric positioning of the mass from the pivotal axis of the
wiper arm all contribute to the effect of the vibrational motion.
The vibrational characteristics are determined by the design and
size of the wiper arm and blade assembly and the natural
26
' ~ ~ ~~ 99~~0
vibrational frequency thereof together with the strength of the
tension spring and the force with which the tension spring urges
the wiper blade against the windshield. Hence, these
characteristics differ from one design to another. In this
embodiment it has been discovered that the means 120 of the
embodiment is particularly effective. In the embodiment, the
electric motor is one made by Sanco Electrical Company and is a 12
volt DC motor having the code number M8M12M24 and operable, in this
embodiment, up to or around 13,500 rpm. The driven shaft of the
motor is secured by solder to the mass 126 which is approximately
45 grams, made from lead and is circular with a diameter of 1.1/4
inches (see Figure 20a) . The axis of the motor lies 3/16 of an
inch from an edge of the mass.
The wiper blade has a length of 16.5 inches and the mounting
axis of the blade is 14.75 inches along the wiper arm from the
pivotal axis of the arm, i.e. at shaft 18. The mass 126 operates
effectively at a distance of 3.5_ inches approximately along the
wiper arm towards the shaft 18, i . a . away from the mounting axis of
the blade to the wiper arm. For guidance, with the mass effective
at this position, a force of between 2 and 3 pounds is necessary,
with the wiper assembly inoperative so as to raise the wiper blade
0.5 inches approximately away from the windshield surface.
However, such a distance is not required in performance of the
invention as lesser distances of movement away from the windshield
will achieve the desired objective, e.g. about .0625 inches or
slightly greater . If distances progressively closer -t~ the shaft
27
~' ~ 2~ 99~~0
18 are chosen for positioning the means 120, vibration of the
assembly becomes less pronounced and progressively larger masses
may become necessary to achieve the inventive effect. In the
embodiment, the rotational axis of the motor and mass is parallel
to -the longitudinal axis of the wiper arm as shown. However, the
motor and mass may be oriented at a different angle to the
longitudinal axis and produce a similar effect. It has also been
found that an eccentric mass of 30 grams has had a similar effect,
but has required slightly longer to remove ice and snow trapped
beneath the wiper blade. It is also found that masses lesser than
30 grams showed a decreasing ice or snow removal effect. With this
particular structure and with a mass below 15 grams in the means
120,. it is found that there is no effect upon removal of ice or
snow either trapped beneath the wiper blade or frozen to it. It is
possible that this smaller mass may achieve the desired effect upon
smaller wiper systems, e.g. headlight wiper systems. In the
construction of the embodiment with the small mass, the wiper blade
does. not move away from the windshield at any position along its
length when no ice or snow is trapped beneath the blade.
In a modification of the sixth embodiment. a mass 130, as
shown in Figure 21 has been used instead of the mass 125. The
mass 130 has a weight of 45 grams and has a substantially crescent
shaped main portion 132 mounted by an integral radial arm 133 to
the driven shaft 124 of the motor 122. The nart of tt~A ctr"nt"rr
with most of the mass, i.e. the main portion 132, located to one
side of the axis of rotation about shaft 124 places the center of
28
~ ~ 9924~
gravity of the mass at a substantially greater distance from the
axis than is found with the mass 126. This positioning of the
center of gravity effectively increases the vibrational force
beyond that possible with mass 126 although both masses are of
substantially equal weights. The mass 130 has a smaller radius,
thu:~ allowing for smaller commercial packaging.
In the sixth embodiment and in the modification thereof, the
vibrational force is sufficiently vigorous to flex parts of the
wiper blade into and out of contact with the windshield when no ice
or snow is present. This effectively produces the desired result
whexz masses of ice or snow are trapped beneath and move with the
wiper blade as the wiper blade moves into and out of contact with
the trapped mass or vigorously vibrates against it. This results
in the release of the mass or in shattering of the mass which
again releases it. Shattering of ice or snow frozen to the wiper
assembly also results. In contrast, as referred to above, it has
been found in tests that when lesser masses have been employed in
vibration generating means to provide less vibrational force, i.e.
no part of the wiper blade has been raised from the windshield,
then.over an unacceptable time period of several minutes, masses of
ice or snow, when trapped, have not been released from beneath the
wiper blade or shattered.
In addition, in the sixth embodiment, vibrational movement may
be effective in removing and/or shattering ice and/or snow
accumulated upon and around the wiper assembly when this is in the
parked, i.e. non-use position, alongside or below a bottom edge of
29
~ 1 g~~~Q
the: windshield. The vibrational force creates cracks in the ice
and snow thereby loosening its hold upon. the wiper arm and blade
and. permitting oscillating movement of the wiper assembly across
the windshield.
In a seventh embodiment as shown in Figure 22, a windshield
wiper assembly 138 which is otherwise similar to the sixth
embodiment has instead of a vibration generating means with an
eccentrically driven mass, a vibration generating means 139 having
a reciprocally driven mass. In the seventh embodiment this
vibration generating means comprises a solenoid actuator 140
mounted upon the wiper arm with the axis of the solenoid actuator
extending substantially normal to the longitudinal direction of the
arm 1b. The solenoid actuator is mounted within a protective
molded surround 142 which has an inside space 143 to allow for
axial movement of the plunger core 144 of the solenoid actuator
within the surround. The surround 142 is secured to the arm 16 by
two spaced metal straps 145. The plunger core is springloaded in
one direction and actuation of the actuator causes movement of the
core into the space 143. The core has a mass such that upon being
actuated intermittently at short spaced intervals, the wiper
assembly 138 is caused to vibrate towards and away from the
windshield. The mass, which may need to include a head weight 14&
at one end of the core, is sufficient for its momentum in
conjunction with the vibrational characteristics of the wiper arm
and blade to produce a sufficiently vigorous vibration of the
assembly 138 as to raise parts of the wiper blade from the surface
,- ~ ~ ~ g9 2 40
of the windshield as in the sixth embodiment, i . e. when ice or snow
is not trapped beneath the blade. The total mass of core and head
weight may be less than is required in the sixth embodiment,
because all of the mass is acting at any particular moment in one
direction and is not at least partly counterbalanced by part of the
mass acting in the opposite direction as with a rotational mass.
This satisfactorily results in removal and/or shattering of masses
of ice or snow when trapped beneath the wiper blade and in
shattering ice or snow frozen to the wiper assembly. The
vibration generating means also includes a driver operated on/off
electronic or electrical switch 148 as shown diagrammatically in
Figure 22, the switch operating a pulsing circuit. This switch,
actuates the solenoid actuator in pulsing fashion by the elctronic
pulsing circuit to produce a required reciprocating movement of the
plunger care which causes the desired vibration of the wiper arm
assembly.
In an eighth embodiment as shown in Figure 23, as in previous
embodiments the wiper arm 16 is carried upon the shaft 18 for
oscillating movement. In this embodiment the means fnr n,nv;»~ +»A
wiper arm and thus the blade away from the windshield comprises a
solenoid actuator 150 which is operably mounted to apply a force
between the shaft 18 and the arm 16. Thus one end of the actuator
is attached either to the shaft 18 or a sleeve (not shown)
surrounding it and the other end is attached to the arm. In this
particular embodiment, the cylindrical housing 152 of the actuator
is pivotally mounted in trunnions 154 to the shaft 18 and at the
31
.° ~ ~ ~ ~9 2 40
other end, the plunger core 156 is pivotally connected by a pivotal
cross-shaft 158 mounted in sides 160 of the wiper arm 16. In this
structure the means for urging the wiper arm towards the windshield
is provided by a return compression spring 162 within the housing
152. Thus, with the actuator de-energized the spring is in an
expanded condition to hold the wiper arm towards the windshield for
normal wiping operation and as shown in full outline in Figure 23.
To release and/or shatter ice or snow debris from beneath the wiper
blade, the solenoid is energized against the spring so that the
plunger core moves upwards and forces the wiper arm 16 to pivot
outwardly and away from the windshield to space the wiper blade
therefrom. This latter position is shown in chaindotted in Figure
23 and corresponds to the chaindotted position in Figure 2.
For those embodiments which can raise the wiper arm away from
the windshield at any point during wiper arm travel (e. g.
embodiments 2, 4 and 8) it may be advantageous to provide a switch
disabling means capable of disabling the lifting action while the
wiper assembly is parked. This,may be especially advantageous on
those vehicles which effectively hide the wiper assembly in the
parked position, e.g. under a cowl assembly. The switch disabling
means may comprise, for example, a mercury switch arrangement
disposed on the wiper arm and electrically connected to disable the
acttuators, e.g. in embodiments 2, 4 and $ from being energized in
the parked position. The switch disabling means may also comprise
a switch which is enabled or disabled dependent on the rotational
position of the drivable mounting.
32
.~ ~ ~ ~ ~ ~ 4~
It is envisaged that the invention in any of its various
eYn~odiments may be sold in kit form. The kit would comprise
replacement arms with or without wiper blades and would include,
for example, the solenoid actuators, and vibrational means together
with any hardware required for mounting to a vehicle.
15
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33
