Note: Descriptions are shown in the official language in which they were submitted.
CA 02296225 2000-O1-17
Adjustable Windshield
Field of the Invention
The present invention pertains to windshields and, more particularly, to an
adjustable
windshield that provides the driver of an open-air vehicle with varying
degrees of frontal
protection.
Background of the Invention
For many decades now, high-speed open-air vehicles such as motorcycles,
snowmobiles,
speedboats, personal watercraft and convertible sportscars have served a
variety of purposes, be
it recreational, competitive or utilitarian.
In the continuing evolution of such vehicles, substantial efforts have been
made to
enhance performance, particularly speed, acceleration and fuel efficiency. In
the design of
motorcycles and snowmobiles, for example, the most common approach in
optimizing
performance is to design small engines that rev higher and deliver more power
and torque.
Another typical strategy to enhance performance entails minimizing the overall
weight through
the use of light materials such as aluminum, plastics and composites.
A third approach to enhance performance involves the reduction of aerodynamic
drag,
an objective common to all high-speed vehicles. At high speeds, aerodynamic
drag becomes a
significant consideration, hampering top speed and diminishing fuel
efficiency. One way for
engineers to reduce the aerodynamic drag that a vehicle experiences at high
speeds is to design
a windshield with a lower frontal profile. With a reduction in aerodynamic
drag comes a
commensurate increase in top speed and fuel efficiency.
On the obverse side of the coin, however, a lower profile windshield means
less
protection for the driver from the elements, notably wind, rain and snow. At
high speeds, the
driver of a motorcycle or snowmobile would probably prefer to hunch forward to
keep his or her
head sheltered by the windshield. Thus, the tradeoff facing open-air vehicle
designers is
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CA 02296225 2000-O1-17
essentially one of performance versus comfort. Whereas a lower profile
windshield would
provide better performance at the expense of frontal protection and comfort, a
higher profile
windshield would provide the inverse, better frontal protection and comfort at
the expense of
performance.
Ideally, however, a windshield should be adjustable so that the driver can
tailor the
height, or profile, of the windshield to match the type of driving he intends
to do. Should the
driver desire to travel at high speeds and to maximize his fuel efficiency, he
would lower the
profile of the windshield to reduce the aerodynamic drag. On the other hand,
should the driver
desire maximum comfort and frontal protection from wind, rain and snow, the
driver would raise
the windshield and sit upright as opposed to hunching forward in the
uncomfortable racing
posture. Of course, with the windshield offering its maximum frontal
protection, the driver
increases aerodynamic drag and sacrifices fuel efficiency. Heretofore,
however, designers of
high-speed open-air vehicles have by and large overlooked the issue of
adjustability in the design
of windshields.
Summary of the Relevant Prior Art
US Patent 4,514,006 (Maruoka) discloses a synthetic resin windscreen for
motorcycles
and motor tricycles. US Patent 4,799,568 (Tanaka) discloses an aerodynamic
front cover for
mufti-wheeled vehicles. Neither patent, however, features adjustability of the
windscreen.
US Patent 4,606,571 (Fujita) discloses an adjustable front-windshield
structure of an
open-top vehicle. The windscreen can be translated vertically. However, the
windshield is not
substantially deformable.
US Patent 4,830,423 (Nebu et al.) discloses an adjustable windshield which can
be
translated with respect to the windshield base. Again, however, the windshield
is not
deformable.
US Patent 4,465,315 (Barstow) discloses a hinged windshield for cycles which
can be
pivoted to from a position offering maximum protection to one offering maximum
exposure.
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No substantial deformation of the windshield is disclosed.
Canadian Patent Application 2,107,534 discloses a support and control device
for a
retractable vehicle windshield. This is another pivotal windshield like
Barstow's described above
and does not allow for deformation of the windshield, only pivoting.
US Patent 4,696,509 (Yagasaki) discloses a windshield adjustment device for
tilting the
windshield from a touring configuration to a racing configuration. The tilt
mechanism comprises
a pair of vertically angled grooves. The edges of the windshield ride in the
grooves. When
raised, the windshield slides in the grooves and becomes more upright. When
lowered, the
windshield is angled by virtue of the grooves. The windshield is not
deformable, however.
US Patent 3,622,196 (Sarra) discloses a windshield for a snowmobile which is
pivotal
from an operative position to a stowed position. The windshield is not
deformable.
US Patent 4,479,663 (Morns et al.) discloses a handlebar mounting for a
fairing which
allows the motorcycle fairing, including the windshield, to be both translated
and pivoted relative
to the motorcycle in order to allow the rider to adopt either a touring
posture or a racing posture.
There is no mention herein of a deformable windshield.
US Patent 4,707,017 (Minobe et al.) discloses an adjustable height windshield
apparatus
for motorcycles. The adjustment mechanism allows the windshield to be raised
or lowered, but
not to be substantially deformed.
Reissued Canadian Patent 23,039 (Comiskey), which was originally Canadian
Patent
2,396,493, discloses a motorcycle windshield for connecting to handlebars. The
windshield is
not deformable.
Canadian Patent 2,237,594 (Dunlap) discloses a foldable windshield for
motorcycles.
Once again, the windshield is not deformable.
US Patent 5,092,262 (Lacy) discloses an adjustable windshield and canopy for a
boat
CA 02296225 2000-O1-17
which can be folded into a variety of configurations.
As evinced by the foregoing survey bf the prior art, there is a need in the
industry for an
adjustable windshield which is deformable from a high-profile touring
configuration to a low-
profile racing configuration.
Object and Statement of the Invention
It is thus an object of the present invention to provide an improved
adjustable windshield
wherein the deficiencies of the prior art are overcome.
It is another object of the present invention to provide an apparatus for
quickly and easily
adjusting the profile of a flexible windshield of an open-air vehicle so that
a driver could opt for
either a low-profile, racing configuration (i.e. minimal protection and
minimal drag) or the more
comfortable, upright, high-profile configuration (i.e. maximum protection and
maximum drag),
or a compromise configuration therebetween.
It is another object of the present invention to provide an apparatus for
adjusting the
windshield without dismounting or alighting from the vehicle.
As embodied and broadly described herein, this invention thus seeks to provide
an
adjustable windshield assembly for an open-air vehicle, said assembly
comprising a substantially
flexible windshield capable of being repeatedly and elastically deformed, said
windshield being
deformable to a plurality of postures between a low-profile posture and a high-
profile posture
and an adjustment mechanism connected to a windshield base and connected to
said flexible
windshield, said adjustment mechanism comprising a rack connected to said
windshield and a
pinion connected to said base and meshing with said rack such that a rotation
of said pinion with
respect to said rack causes the flexible windshield to displace and deform
relative to the base.
This arrangement allows the driver to quickly and easily adjust the windshield
according
to the riding conditions. If the driver seeks maximum comfort and protection,
the windshield can
be raised. If the driver seeks optimal aerodynamic performance, the windshield
can be lowered.
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CA 02296225 2000-O1-17
The invention further seeks to provide an adjustable flexible windshield for
use with a
snowmobile, said snowmobile including a chassis defining a tunnel; an engine
mounted to said
chassis; a ground-engaging track connected to said engine via an output shaft
and drive sprocket;
a rear suspension assembly for mounting said track to said chassis; a seat
mounted to said chassis
generally above said tunnel; a pair of steerable skis, each of said ski being
mounted to said
chassis via a front suspension and being connected to a pair of handlebars via
a steering linkage;
said snowmobile further including a cab covering said engine; said cab
defining a windshield
base for supporting said adjustable, flexible windshield; and an adjustment
mechanism connected
to both said flexible windshield and said windshield base for displacing said
flexible windshield
relative to said windshield base.
Preferably, the adjustable windshield is capable of being repeatedly and
elastically
deformed without a substantial degradation of strength, stiffness, resilience,
elasticity,
appearance and translucence. The windshield can be repeatedly adjusted without
damaging the
windshield, reducing its structural integrity or impairing the visibility.
Preferably, the rack is formed integrally along a side of a slot within said
windshield.
This reduces the number of parts involved in the adjustment mechanism, keeping
costs and
assembly time at a minimum.
Preferably, the adjustable windshield is made of polycarbonate or a similarly
transparent
and flexible plastic. Such materials are resilient, tough and resistant to
scratching and cracking
in all kinds of weather conditions.
Other objects and features of the invention will become apparent by reference
to the
following description and drawings.
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CA 02296225 2000-O1-17
Brief Description of the Drawings
A detailed description of the preferred embodiments of the present invention
is provided
below with reference to the following drawings, in which:
Figure 1 is a side elevational view of a snowmobile disposed with an
adjustable
windshield in accordance with the present invention;
Figure 2 is a side front elevational view of a rack and pinion adjustment
mechanism in
accordance with a preferred embodiment of the present invention; and
Figure 3 is an exploded view of the rack and pinion adjustment mechanism of
Figure 2
In the drawings, the preferred embodiments of the invention are illustrated by
way of
example. It is to be expressly understood that the description and drawings
are only for purposes
of illustration and to facilitate understanding, and are not intended to be a
definition of the limits
of the invention.
Detailed Description of Preferred Embodiments
Referring to Figure 1, an adjustable windshield assembly 10 comprises a
flexible
windshield 20 and a windshield base 30. The flexible windshield 20 can be
raised to a high-
profile posture 22 or returned to a low-profile posture 24. The high-profile
posture offers
maximum protection from wind, rain, and snow but creates the most aerodynamic
drag on the
vehicle. The high-profile posture is also known as a touring posture because
the driver typically
sits in a comfortable upright position. The low-profile posture offers minimum
protection from
the elements but creates minimal aerodynamic drag on the vehicle. The low-
profile posture is
also known as a racing posture because the driver typically hunches or leans
forward. The
windshield normally can be adjusted to any posture intermediate the high-
profile and low-profile
postures.
The flexible windshield 20 can be repeatedly and elastically deformed without
a
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substantial degradation of strength, stiffness, resilience, elasticity,
appearance or translucence.
The windshield is preferably made of a clear, tough, resilient plastic like
polycarbonate (which
is an ester of carbonic acid and an aromatic bisphenol). Preferably, the
windshield 20 is
deformed when it is moved from the high-profile posture to the low-profile
posture and vice
versa. The polycarbonate windshield does not acquire a permanent set when it
is in either the
high-profile or low-profile posture. The adjustable windshield itself is made
from a transparent,
flexible plastic that can be repeatedly and elastically deformed without
degrading its key
mechanical properties. Although the preferred material for this particular
windshield is
polycarbonate, there are other plastics having similar mechanical properties
and transparence that
could be substituted for polycarbonate such as transparent acrylics.
Polycarbonates, however,
are generally preferred for their superior impact strength. It should be noted
for the purposes of
this specification that the term transparent includes windshields that are
tinted.
At the junction of the flexible windshield 20 and the windshield base 30 is a
rubber,
plastic or foam interface. While the windshield 20 is displaced and deformed,
it is also
maintained in substantial contact with the base 30 (via the interface) by
virtue of fasteners, inserts
or retaining springs so that at most only an insubstantial amount of air can
flow through the
interface of the windshield and base in any posture.
The adjustment (i.e. raising or lowering) of the flexible windshield 20
between the high-
profile posture 22 and the low-profile posture 24 is achieved by operating an
adjustment
mechanism 40 that comprises a rack 42 and a pinion 44. The rack 42 is formed
integrally with
the windshield 20. The rack 42 can be formed by molding or end-milling of the
windshield 20.
Integrally formed in the windshield 20 is also a slot 41. The slot 41 is
disposed at least
somewhat vertically to allow the windshield 20 to be displaced in a somewhat
vertical direction.
The rack 42 has a plurality of teeth which are aligned along one side of the
slot 41 such that the
teeth protrude into the slot. The teeth of the rack 42 mesh with the teeth of
equal size and pitch
formed around the periphery of the pinion 44. The rack 42 is thus fixed to or
integral with the
windshield 20 so that it translates with respect to the base 30 or the rest of
the vehicle.
As illustrated in Figure 3, the windshield 20 is sandwiched between a cap 46
and a knob
45. The windshield base 30 is maintained in place by a retainer 49 and a
fastener 38. The plate
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CA 02296225 2000-O1-17
holder 36 has a cavity 21 into which a plug portion 47 of the cap 46 is fitted
when the adjustment
mechanism 40 is assembled. The pinion 44 is at least partially enclosed by the
knob 45 and the
cap 46. The knob 45 is disposed with a plurality of gripping portions 43. The
gripping portions
43 are arranged circumferentially around the outer perimeter of the knob. The
gripping portions
are ridge-like protrusions equally spaced around the outside surface of the
knob 45.
Equivalently, the gripping portions can be either depressions sunken into the
knob 45, knurling,
or regions of roughened, high-friction material as long as the end result is
that the grip on the
knob is enhanced. Since the knob 45 is used primarily for open-air vehicles
like snowmobile,
motorcycles or straddle-type vehicles and are thus commonly exposed to rain,
snow and ice, the
gripping portions are helpful for improving the grip of the knob, especially
if the driver's hands
are encumbered by thick gloves.
The retainer 49 penetrates a central cavity in the knob 45, a central cavity
in the pinion
44 and engages the plug portion 47 of the cap 46. The fastener 38 fixes the
windshield base 30
to the retainer 49. The retainer 49 fits into the plug portion 47 of the cap
46. The plug portion
of the cap 46 has an outer profile that mates with the cavity 21 of the plate
36. The plate 36 is
thus fastened to the windshield base 30. It is understood that the plate
holder 36 can be
eliminated if the inside surface of the windshield base 30 comprises a cavity
that mates with the
outer profile of the cap 46. A coil spring 48 encircles the retainer 49 in
order to give the
adjustment mechanism a degree of elasticity or play along the axis of the
retainer and fastener.
The spring 48 urges the knob 45 against windshield 20 thereby locking the
adjustment
mechanism in a desired position. The retainer 49 has a square end portion for
engaging with a
matching square cavity on the plug portion 47 of the cap 46. This ensures that
the retainer 49
and the cap 46 remain angularly aligned {i.e. do not rotate with respect to
one another about the
axis defined by the retainer and fastener). The knob 45 is rotatably engaged
with the pinion 44
so that turning the knob turns the pinion. The pinion 44 is non-rotatably
engaged to the cap 46
so that the pinion is free to rotate within the inner confines of the cap. The
cap 46 is prevented
from rotating with the knob because the plug portion 47 of the cap is fitted
into the cavity 21 of
the plate holder 36. The spring 48 is selected to have a stiffness
sufficiently low that it allows
the adjustment mechanism to be operated manually and without undue wear of
tightly interfaced
parts. On the other hand, the spring 48 must have a sufficiently high
stiffness such that the
adjustment mechanism remains in place, and does not vibrate or rattle around.
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CA 02296225 2000-O1-17
Normally, the open-air vehicle has two adjustment mechanisms as described
herein, one
on each side of the flexible windshield to allow for symmetrical displacement
and deformation
of the windshield.
In operation, the driver who wishes to either raise the windshield to the high-
profile
posture 22 or to lower the windshield to the low-profile posture 24 simply
toms the knob 45. As
seen above, the rack 42 is an integral portion of the windshield 20 and is
movable relative to the
base 30 while the pinion 44, the knob 45 and the cap 46 are fixed. The cap 46
is matingly
connected to the cavity 21 in the plate 36. Any rotation of the knob 45 causes
the rack 42 to
travel along the pinion 44 and the windshield 20 is thus displaced with
respect to the base 30.
The same operation is performed either sequentially or simultaneously on the
second adjustment
mechanism. Since the windshield is flexible, the displacement of the
windshield on both sides
results in a deformation of the windshield. The adjustment mechanism may
comprise a plurality
of gradations for making symmetrical adjustments to the windshield.
Alternatively, it may have
a rotary member that can only be rotated in discrete amounts, similar to a
Geneva mechanism in
order to limit the adjustability of the rack and pinion to precise, discrete,
predetermined steps.
The rack and pinion may also have a locking mechanism to lock the rack
relative to the pinion.
It is understood that the adjustment mechanism may be motorized by providing
an
electrical switch, a reversible electric motor and a gear train transmission
that is self locking.
Indeed, in this construction, the vehicle comprises an electrical switch
carried by, or juxtaposed
to, the steering control of the vehicle. This switch is operatively connected
to one or two
reversible motors. The motor has an output shaft drivingly connected to a worm
gear which is,
in turn, enmeshed with a worm wheel. The teeth of this worm wheel mesh with
the teeth of
equal size and pitch of those formed integrally with, or connected to, the
windshield. This type
of construction is well known in the art and has been used in cars for many
years (e.g. power
windows).
The above description of preferred embodiments should not be interpreted in a
limiting
manner since other variations, modifications and refinements are possible
within the spirit and
scope of the present invention. The scope of the invention is defined in the
appended claims and
their equivalents.
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