Note: Descriptions are shown in the official language in which they were submitted.
File number: 9265 - 113
Title of the Invention
[0001] Traction Assembly for Vehicle
Cross-Reference to Related Applications
[0002] The present patent application is a divisional application of Canadian
patent
application No. 2,735,095 entitled "Traction Assembly for Vehicle" and filed
on March
24, 2011.
Field of the Invention
[0003] The present invention generally relates to traction assemblies and
track systems
typically used as wheel replacements for wheeled vehicles. More particularly,
the present
invention relates to traction assemblies and track systems for use as wheel
replacements
for all-terrain vehicles (ATV), utility terrain vehicles (UTV) and other
similar vehicles.
Background of the Invention
[0004] Tractions assemblies for use as wheel replacement on wheeled vehicles
are known
in the art. Indeed, several configurations of traction assemblies have been
proposed
throughout the years in order to generally improve different aspects and
characteristics
such as the riding behaviour.
[0005] While the riding behavior is one of the most important aspects involved
in the
concept of a vehicle, the ability to allow interchangeability of parts or to
retrofit new
components on existing vehicles greatly satisfies the owner of vehicles and
represents an
interesting market source for vendors of specialized parts destined to
vehicles such as
snowmobiles, motorcycles, ATVs, tractors, trucks, etc.
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File number 9265 - 113
Revision: as filed
Date: March 18. 2019
[0006] For instance, different riding assemblies are sometimes installed to
replace the
wheels of existing vehicles. In principle, the assemblies should minimize the
need to
change existing components, must be able to fit on the vehicle without
interference and
should try to minimize any negative change to the overall riding behavior of
the vehicle
and comfort of the driver.
[0007] However, by replacing the wheels by traction assemblies, or track
systems, the
mass distribution of the sprung and unsprung mass of the vehicle is modified.
Indeed, the
mass of a traction assembly is usually superior to the mass of the replaced
wheel. By
.. increasing the unsprung mass of a vehicle, it causes a change in the mass
repartition (ratio
sprung/unsprung mass) and may cause the springs and shock absorbers to be less
effective in controlling the suspension's movement, it can cause discomfort
for the user
and it negatively affects vehicle handling.
[0008] There is therefore a need for a traction assembly which improves riding
condition
when traction assemblies are used to replace existing wheels on vehicles.
Summary of the Invention
[0009] The principles of the present invention are generally embodied in a
traction
assembly which uses, for propulsion, a longitudinally extending traction band
or endless
track disposed around and cooperating with a sprocket wheel, a supporting
structure, and
idler and/or road wheels. The supporting structure of the traction assembly
comprises a
suspension comprising a spring assembly and a dampener. In use, the suspension
of the
vehicle is typically replaced by a rigid bar or member and the dampening is
assured by
the suspension of the traction assembly.
[0010] The suspension of the vehicle may be replaced with a rigid member that
is
adjustable in length, for example by using an electric or pneumatic adjusting
device. The
adjustable rigid member allows the modification of the height of the vehicle
following the
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driver needs. The height of the vehicle may be modified to adjust ground
clearance or to
modify the height of the gravity center of the vehicle.
[0011] It is to be noted that the present invention could be used with a
vehicle that does
not comprises a suspension, such as a tractor.
[0012] The present invention involves a traction assembly that can preferably
replace a
wheel on vehicle. Preferably, the traction assembly can replace wheels on
either side of
the front portion and/or the rear portion of the vehicle.
[0013] In a ground vehicle with a suspension, the sprung mass (or sprung
weight) is the
portion of the vehicle's total mass that is supported by the suspension,
including in most
applications an important proportion (half or more) of the mass of the
suspension itself.
The sprung mass typically includes the body, the frame, the internal
components of the
vehicle, the passengers, etc. The sprung mass does not include the mass of the
components below the suspension components. The unsprung mass (or the unsprung
weight) is the mass of the suspension (usually half the mass of the
suspension), wheels or
tracks (as applicable), and other components directly connected to the
suspension (such
as the hub, the disk brake, etc...), rather than supported by the latter, or
the mass
.. following the ground.
[0014] The larger the ratio of sprung mass to unsprung mass, the less the body
and
vehicle passengers are affected by bumps and other surface imperfections.
.. [0015] Usually, in devices of prior art, all the mass of the traction
assemblies replacing
wheels are considered unsprung mass. The presence of a suspension in the
support
structure of the traction assembly allows a part of its mass to become sprung
mass; the
unsprung mass of the vehicle is thus reduced and it improves the riding
comfort.
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[0016] In a first embodiment, the traction assembly for the replacement of
wheels in a
vehicle having a first ratio of sprung mass to unsprung mass, the traction
assembly
comprising:
a. a sprocket wheel configured to be mounted to the vehicle;
b. a supporting structure comprising a suspension assembly;
c. idler wheels pivotally mounted to the supporting structure;
d. road wheels pivotally mounted to the supporting structure;
e. a traction band disposed about the sprocket wheel, the idler wheels and a
road;
f. wherein when the traction assembly is mounted to the vehicle, the
suspension assembly of the traction assembly causes the vehicle to have a
second ratio of sprung mass to unsprung mass, the second ratio being
different from the first ratio.
[0017] In a second embodiment, the second ratio is greater than the first
ratio.
[0018] Other aspects and many of the attendant advantages will be more readily
appreciated as the same becomes better understood by reference to the
following detailed
description and considered in connection with the accompanying drawings in
which like
reference symbols designated like elements throughout the figures.
Brief Description of the Drawings
[0019] The above and other objects, features and advantages of the invention
will
become more readily apparent from the following description, reference being
made to
the accompanying drawings in which:
[0020] Figure 1A is a perspective view of a traction assembly in accordance
with the
principles of the present invention, as installed at the front right of a
vehicle.
[0021] Figure 1B is a perspective view of a traction assembly in accordance
with the
principles of the present invention, in a compressed configuration.
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[0022] Figure IC is a perspective view of a traction assembly in accordance
with the
principles of the present invention, as installed at the front right of a
vehicle having the
original vehicle suspension attached thereto.
[0023] Figure 2 is another perspective view of the traction assembly of Fig.
I.
[0024] Figure 3 is an outer side view of the traction assembly of Fig. 1.
[0025] Figure 4 is a partial outer side view of the traction assembly of Fig.
1 with the
dampener in a fully compressed configuration.
[0026] Figure 5 is a partial outer side view of the traction assembly of Fig.
1 with the
dampener in a partially compressed configuration.
[0027] Figure 6 is a partial outer side view of the traction assembly of Fig.
1 with the
dampener in an uncompressed configuration.
[0028] Figure 7 is a partial outer side view showing more particularly the
linkage of the
traction assembly.
[0029] Figure 8 is a partial inner side view showing the position of the
sprocket wheel
when the dampener is in a fully compressed configuration.
[0030] Figure 9 is a partial inner side view showing the position of the
sprocket wheel
when the dampener is in a partially compressed configuration.
[0031] Figure 10 is a partial inner side view showing the position of the
sprocket wheel
when the dampener is in an uncompressed configuration.
[0032] Figure 11 is a front view of the reinforcing member.
[0033] Figure 12 is a perspective view of the first linkage.
[0034] Figure 13 is a front view of the second linkage.
[0035] Figure 14 is a perspective view of the third linkage.
[0036] Figure 15 is a perspective view of the guide rail.
[0037] Figures 16A to 16E show the configuration of the traction assembly for
different
dampener compression state, from an uncompressed state in Fig. 16a to a fully
compressed state in Fig. 16e.
[0038] Figures 16F and 16G show the angle between the ground and the lower run
of the
traction band.
[0039] Figure 17A is a top view of a spring assembly used with the present
traction
assembly.
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[0040] Figure 17B is a side view of the spring assembly of Figure 17A.
[0041] Figure 17C is a cross-section view of the spring assembly of Figure
17A, along
line A-A.
[0042] Figure 17D is a perspective view of the spring assembly of Figure 17A.
[0043] Figure 17E is a partial view of the spring assembly of Figure 17E.
[0044] Figure 18 is a perspective view of the traction assembly comprising an
adjustable
rigid member.
Detailed Description of the Preferred Embodiment
[0045] A novel traction assembly for vehicle will be described hereinafter.
Although the
invention is described in terms of specific illustrative embodiments, it is to
be understood
that the embodiments described herein are by way of example only and that the
scope of
the invention is not intended to be limited thereby.
[0046] The following description will be made according to embodiments of the
present
invention designed to be installed on ATVs, UTVs, and other similar vehicles
such as
tractors, military cars or trucks. However, it is to be understood by the
skilled addressee
that the present invention can be adapted for any wheeled vehicles. Therefore,
variants of
the present invention adapted to be used on trucks, tractors and other similar
vehicles fall
inside the scope of the present invention.
[0047] The traction assembly 10 can replace the front and/or the rear wheels,
or the skis
assemblies, of a vehicle. Other vehicles designed to ride on irregular, snowy,
sandy,
muddy or softer terrains can also incorporate the use of traction assembly 10.
The traction
assemblies 10 can be mounted on each side of the front and rear portion of a
vehicle.
[0048] The present traction assembly comprises linkages and a suspension
comprising a
dampener and a spring assembly allowing a part of the traction assembly to be
part of the
sprung mass of the vehicle. The suspension of the vehicle, if the vehicle has
one, that is
connected to the chassis and to the wheel is replaced by a rigid member. The
suspension
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function for the vehicle is assumed by the suspension of the traction
assembly. The
linkages are articulated and allow the traction assembly to follow the
movement of the
dampener and of the spring assembly when the vehicle passes over bumps or
depressions
on the ground.
[0049] Referring first to Figs. 1 to 3, a traction assembly 10 embodying the
principles of
the invention is shown. The traction assembly 10 comprises a sprocket wheel
200 adapted
to be mounted to a shaft of a wheeled vehicle (not shown), frame elements 301
and 302
coupled to the sprocket wheel 200 through the mounting axle 370, a guide rail
40, idler
wheels 600 and 700 respectively mounted at the fore and at the aft of the
guide rail 40,
and road wheels 500 mounted along the length of the guide rail, typically on
each side
thereof.
[0050] The traction assembly 10 also comprises a traction band 100, typically
but not
necessarily made of reinforced elastomeric material. The traction band 100 has
an inner
surface configured to cooperate, via a plurality of typically longitudinally
aligned drive
lugs and guide lugs (not shown for clarity), with the sprocket wheel 200, the
idler wheels
600 and 700, the road wheels 500 and the guide rail 40. The traction band 100
also has an
outer surface comprising a plurality of traction lugs (not shown for clarity)
configured to
engage the ground onto which the traction assembly 10 is operated.
[0051] The traction assembly comprises a suspension comprising a dampener 450
and a
spring assembly 452 that will be described in more details here after.
[0052] The sprocket wheel 200 is typically circular in shape and preferably,
but not
exclusively, made from light yet resistant material such as ultra high
molecular weight
polyethylene ("UHMW-PE"). Still, other material could be used; the present
invention is
not so limited.
[0053] In the present embodiment, the sprocket wheel 200 defines a first side
202, a
second side 204. Respectively laterally extending from the first surface 202
and the
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second surface 204 are equally spaced sprocket teeth. The sprocket teeth are
configured
to conventionally engage the drive lugs (not shown) disposed on the inner
surface of the
traction band 100. The sprocket wheel 200 also comprises a central bore 211
configured
to receive ball bearings (not shown) and the mounting axle 370. Disposed
around the
central bore are four smaller bores configured to receive the fasteners used
to secure the
sprocket wheel 200 to the shaft or wheel hub of the vehicle. Understandably,
the number
of bores can vary according to the configuration of the shaft (not shown) onto
which the
sprocket wheel 200 will be mounted; the present invention is thus not limited
to four
bores.
[0054] As the skilled addressee will understand, the present traction assembly
10 is
generally not limited to a particular configuration of sprocket wheel.
[0055] Referring now to Fig. 8, the guide rail 40 is coupled with a slider 420
which
longitudinally or circumferentially extends in such a way as to give form to
the traction
band 100. As shown in more details in Fig. 15, the guide rail 40 comprises two
lateral
walls 41 adapted to receive the sprocket wheel 200.The guide rail 40 comprises
pivot
points that are adapted to receive a pivot joint on which the linkages, that
will be
described hereafter, will be connected.
[0056] The frame 300 comprises the frame elements 301 and 302.
[0057] Referring now to Fig. 3, the suspension of the traction assembly 10
comprises a
dampener 450 and a spring assembly 452. The dampener 450 is pivotally
connected to
the frame 300 through the pivot joint 360 and to the guide rail 40 through the
pivot joint
361.
[0058] Now referring to Fig. 7, comprising only some parts of the traction
assembly to
facilitate viewing of the different parts of the traction assembly, the
traction assembly 10
comprises a plurality of articulated linkages 310, 320 and 330. The member 340
is used
as reinforcement.
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[0059] Referring to Figs. 4 to 6, Fig. 7 and to Fig. 11, the first linkage 310
comprises
only one linking member. The second linkage 320 comprises the linking members
331,
332 and 333 and the extendable linking member 400. The member 340 is
interconnected to the second linkage 320 as best illustrated in Fig. 7. The
third linkage
330 comprises only one linking member. The different linking members of the
linkages
are connected together with pivot joints. It is to be understood that the
number and the
configuration of the linkages are not limited to the version shown in the
present preferred
embodiment. Indeed, the function of the linkages is to allow the mobility of
the sprung
mass of the traction assembly relatively to the unsprung mass and this could
be achieve
with other configurations of linkages.
[0060] The extendable linking member 400 is interconnected to the guide rail
40 and to
the second linkage 320. The extendable linking member 400 comprises a spring
405, a
first portion 410, a second portion 420 and a retaining portion 430 shown in
Figs. 17A to
17E. The spring 405 is connected to the first portion 410 and to the retaining
portion 430,
the retaining portion 430 being connected to the second portion 420. The first
portion 410
is adapted to slide into said second portion 420 to follow the compression and
extension
of the spring 405. The function of the extendable linking member 400 is to
establish the
optimum tension in the traction band to compensate for the modification of its
length in
use. The length of the traction band may slightly vary due to the presence of
the
suspension that change the configuration of the traction assembly and
consequently the
perimeter formed by the sprocket wheel 200, idler wheels 600 and 700, and road
wheels
500. The extendable linking member 400 prevent the traction band 100 to become
too
loose or too stretched following the modification of the perimeter formed by
the sprocket
wheel, the idler wheels and the road wheels. in the preferred embodiment. the
extendable
linking member 400 preferably comprises an aperture through which the
suspension
assembly typically extends.
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[0061] As it can be seen in Fig. 4 to Fig. 6, the position of the wheel 700
and of the third
linkage 330 is variable. In Fig. 4, the position of the wheel 700 is higher
than the
configuration shown in Fig. 6, relatively to the guide rail 40.
[0062] As explained previously, the linkages are connected through pivot
joints that are
illustrated in more details in Fig. 7. The extremities of the first linkage
310 are connected
to the upper portion 44 of the guide rail 40 at pivot joint 350 and to the
frame 300 at pivot
joint 352. The second linkage 320 is interconnected to the member 310 by the
extendable
linking member 400. As best illustrated in Fig. 7, the first portion 410 of
the extendable
linking member 400 is pivotally connected to the member 310 at pivot joint 353
while the
second portion 420 is pivotally connected to the guide rail 40 at pivot joint
362. The
second linkage 320 is further pivotally connected to the third linkage 330 at
pivot joint
355. Finally, the third linkage 330 is connected to the second linkage 320 at
pivot joint
355 and to the lower portion 43 of the guide rail 40 at pivot joint 356.
Notably, as best
.. shown in Fig. 7, the pivot joint 356 is typically located at the front (or
fore) of the lower
portion 43. It is to be noted that the pivot joints described above, namely
350, 352, 353,
355 and 356, have a rotation axis that is substantially perpendicular to the
rotation axis of
the sprocket wheel 200. Pivot joints for such use are already known in prior
art.
[0063] The frame 300 is connected to the sprocket wheel 200 through the
mounting axle
370. The frame 300 is also connected to the upper extremity of the dampener
450 through
pivot joint 360. The frame 300 is connected to the first linkage 310 through
pivot joint
352 and to the second linkage 320 through pivot joint 362.
[0064] To install the traction assembly of the present invention on a vehicle,
the user
dismounts the wheels of the vehicle and fixes traction assemblies 10 on the
mounting
axle 370. The suspension of the vehicle is dismounted and replaced by a rigid
member
60, as shown in the Figures and more particularly in Fig. 1.
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[0065] As it can be seen more particularly in Figs. 4 to 6, the configuration
of the traction
assembly 10 changes according to the compression and the decompression of the
dampener 450 and of the spring assembly 452.
[0066] In the present traction assembly 10, the unsprung mass comprises the
idler wheel
600 and 700, the road wheel 550 and the support structure 45, the member 310,
the third
linkage 330, the guide rail 40. It is approximated that half the mass of the
first linkage
310, of the second linkage 320 and of the suspension is considered to be
unsprung mass
and the other half is sprung mass. The sprocket wheel 200, the frame 300 and
the
elements connecting the sprocket wheel 200 to the vehicle are part of the
sprung mass.
[0067] The linkages comprise articulated or pivot joints providing two-
dimensional
adjustability to follow the compression and decompression of the dampener 450,
of the
spring assembly 452 and of the extendable linking member 400. This
adjustability allows
the traction band to maintain substantially the same predetermined length (the
perimeter
formed by the external surface of the sprocket wheel 200, the idler wheels 600
and 700
and the road wheels 500) during the operation of the vehicle.
[0068] As it can be seen in Figs. 8 to 10, the position of the sprocket wheel
200 varies
with the compression and decompression of the dampener 450 and of the spring
assembly
452. In the lowest position shown in Fig. 8, the sprocket wheel is received
between the
lateral walls 41 of the guide rail 40 (shown in more detail in Fig. 15).
[0069] Referring to Figs. 4 to 6, the position of the idler wheel 700 varies
according to
the movement of the second linkage 320 and the third linkage 330.
[0070] Figures 16a to 16e show the configuration of the traction assembly for
different
dampener compression state, from an uncompressed state in Fig. 16a to a fully
compressed state in Fig. 16e. Figs. 16f and 16g show the angle between the
ground and
.. the lower run of the traction band that the traction assembly can adopt
when passing over
a bump or a depression on the ground.
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[0071] Figure 18 illustrates another embodiment of the invention wherein the
suspension
of the vehicle has been replaced with an adjustable rigid member 160. The
height of the
adjustable rigid member 160 may be modified by the driver of the vehicle. The
adjustable
rigid member 160 may be actuated using a pneumatic or electric device, for
example.
[0072] The present invention provides a traction assembly having a lower
unpsrung mass
compared to traction assemblies of prior art, where substantially all the
traction assembly
is considered to be unsprung mass. This is achieved by providing a traction
assembly
having a suspension allowing a part of the mass of the traction assembly to
become
sprung mass. By decreasing the unsprung mass, the comfort of passengers using
an ATV
with the present traction assembly is increased.
[0073] While illustrative and presently preferred embodiment(s) of the
invention have
been described in detail hereinabove, it is to be understood that the
inventive concepts
may be otherwise variously embodied and employed and that the appended claims
are
intended to be construed to include such variations except insofar as limited
by the prior
art.
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