U.S. patent application number 14/688842 was filed with the patent office on 2015-10-15 for track assembly for an all-terrain vehicle (atv) or other tracked vehicle.
The applicant listed for this patent is CAMOPLAST SOLIDEAL INC.. Invention is credited to Jean Bernard, Stephane Pilette, Jeremie Zuchoski.
Application Number | 20150291235 14/688842 |
Document ID | / |
Family ID | 43029175 |
Filed Date | 2015-10-15 |
United States Patent
Application |
20150291235 |
Kind Code |
A1 |
Zuchoski; Jeremie ; et
al. |
October 15, 2015 |
TRACK ASSEMBLY FOR AN ALL-TERRAIN VEHICLE (ATV) OR OTHER TRACKED
VEHICLE
Abstract
A track assembly for providing traction to an all-terrain
vehicle (ATV) or other tracked vehicle. The track assembly may
comprise a wheel device for contacting an inner side of an endless
track such that a longitudinal end segment of the endless track
turns around the wheel device. The wheel device allows a change in
curvature of the longitudinal end segment of the endless track when
the longitudinal end segment of the endless track contacts an
obstacle on the ground. In some embodiments, the wheel device may
comprise a resilient wheel that is elastically deformable. In other
embodiments, the wheel device may comprise a wheel carrier carrying
a plurality of carried wheels.
Inventors: |
Zuchoski; Jeremie;
(Sherbrooke, CA) ; Bernard; Jean;
(Saint-Mathieu-du-Parc, CA) ; Pilette; Stephane;
(Canton de Hatley, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CAMOPLAST SOLIDEAL INC. |
Sherbrooke |
|
CA |
|
|
Family ID: |
43029175 |
Appl. No.: |
14/688842 |
Filed: |
April 16, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12767895 |
Apr 27, 2010 |
9033430 |
|
|
14688842 |
|
|
|
|
61173627 |
Apr 29, 2009 |
|
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Current U.S.
Class: |
305/142 |
Current CPC
Class: |
B62D 55/02 20130101;
B62D 55/12 20130101; B62D 55/075 20130101; B62D 55/084 20130101;
B62D 55/14 20130101; B62D 55/24 20130101; B62K 5/01 20130101; B62M
27/02 20130101; B62D 11/20 20130101; B62D 55/065 20130101 |
International
Class: |
B62D 55/084 20060101
B62D055/084; B62D 55/065 20060101 B62D055/065; B62D 55/24 20060101
B62D055/24; B62D 55/14 20060101 B62D055/14; B62D 11/20 20060101
B62D011/20; B62D 55/12 20060101 B62D055/12 |
Claims
1.-47. (canceled)
48. A track assembly for traction of a vehicle, the track assembly
comprising: a) a track comprising a ground-engaging outer side for
engaging the ground and an inner side opposite to the
ground-engaging outer side; and b) a track-engaging arrangement for
driving and guiding the track around the track-engaging
arrangement, a bottom run of the track extending under the
track-engaging arrangement, the track-engaging arrangement
comprising: i. a drive wheel for driving the track; and ii. a
plurality of guiding wheels contacting the bottom run of the track;
wherein: an axis of rotation of a given one of the guiding wheels
is movable relative to an axis of rotation of the drive wheel when
the track assembly moves on the ground; and the given one of the
guiding wheels is resilient to be elastically deformable when the
track assembly moves on the ground.
49. The track assembly of claim 48, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the given one of the guiding wheels is a given one of
the leading idler wheel and the trailing idler wheel.
50. The track assembly of claim 49, wherein the given one of the
leading idler wheel and the trailing idler wheel is the leading
idler wheel.
51. The track assembly of claim 50, wherein: an axis of rotation of
the trailing idler wheel is movable relative to the axis of
rotation of the drive wheel when the track assembly moves on the
ground; and the trailing idler wheel is resilient to be elastically
deformable when the track assembly moves on the ground.
52. The track assembly of claim 48, wherein the plurality of
guiding wheels includes: a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and a plurality of support wheels disposed between the
leading idler wheel and the trailing idler wheel in the
longitudinal direction of the track assembly.
53. The track assembly of claim 52, wherein the given one of the
guiding wheels is a given one of the leading idler wheel and the
trailing idler wheel.
54. The track assembly of claim 48, wherein the given one of the
guiding wheels comprises a non-pneumatic tire.
55. The track assembly of claim 48, wherein the given one of the
guiding wheels comprises foam.
56. The track assembly of claim 55, wherein the foam is closed-cell
foam.
57. The track assembly of claim 56, wherein the closed-cell foam is
closed-cell polyurethane foam.
58. The track assembly of claim 55, wherein the foam forms at least
part of a periphery of the given one of the guiding wheels.
59. The track assembly of claim 53, wherein an outer diameter of
the given one of the leading idler wheel and the trailing idler
wheel is greater than an outer diameter of a given one of the
support wheels.
60. The track assembly of claim 59, wherein the given one of the
leading idler wheel and the trailing idler wheel is wider than the
given one of the support wheels in a widthwise direction of the
track assembly.
61. The track assembly of claim 53, wherein the given one of the
leading idler wheel and the trailing idler wheel is wider than a
given one of the support wheels in a widthwise direction of the
track assembly.
62. The track assembly of claim 49, wherein: the track-engaging
arrangement comprises a frame supporting the leading idler wheel
and the trailing idler wheel; and a width of the given one of the
leading idler wheel and the trailing idler wheel in a widthwise
direction of the track assembly occupies at least a majority of a
distance between a lateral surface of the given one of the leading
idler wheel and the trailing idler wheel and a center of the frame
in the widthwise direction of the track assembly.
63. The track assembly of claim 48, wherein: the inner side of the
track comprises a plurality of wheel-contacting projections for
contacting at least one of the drive wheel and the guiding wheels;
and a width of the given one of the guiding wheels in a widthwise
direction of the track assembly is greater than a dimension of a
given one of the wheel-contacting projections in the widthwise
direction of the track assembly.
64. The track assembly of claim 63, wherein the plurality of
wheel-contacting projections comprises a plurality of drive
projections and the drive wheel comprises a sprocket for engaging
the drive projections.
65. The track assembly of claim 49, wherein: the given one of the
guiding wheels is a first given one of the guiding wheels; an axis
of rotation of a second given one of the guiding wheels is movable
relative to the axis of rotation of the drive wheel when the track
assembly moves on the ground; the second given one of the guiding
wheels is spaced apart from the first given one of the guiding
wheels in a widthwise direction of the track assembly; the second
given one of the guiding wheels is resilient to be elastically
deformable when the track assembly moves on the ground; and the
first given one of the guiding wheels and the second given one of
the guiding wheels collectively occupy a majority of a span of the
first given one of the guiding wheels and the second given one of
the guiding wheels in the widthwise direction of the track
assembly.
66. The track assembly of claim 48, wherein a radial extent of the
given one of the guiding wheels corresponding to at least 20% of an
outer radius of the given one of the guiding wheels is elastically
deformable when the track assembly moves on the ground.
67. The track assembly of claim 48, wherein the track-engaging
arrangement comprises a frame supporting the guiding wheels and
mounted about the axis of rotation of the drive wheel.
68. The track assembly of claim 48, wherein the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the track-engaging arrangement comprises a frame
supporting the guiding wheels and having a pivot point located
between the leading idler wheel and the trailing idler wheel in the
longitudinal direction of the track assembly.
69. The track assembly of claim 68, wherein the pivot point of the
frame corresponds to the axis of rotation of the drive wheel.
70. The track assembly of claim 48, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and a distance between the axis of rotation of the drive
wheel and an axis of rotation of the leading idler wheel in the
longitudinal direction of the track assembly is different from a
distance between the axis of rotation of the drive wheel and an
axis of rotation of the trailing idler wheel in the longitudinal
direction of the track assembly.
71. The track assembly of claim 48, wherein the inner side of the
track comprises a plurality of drive projections and the drive
wheel comprises a sprocket for engaging the drive projections.
72. The track assembly of claim 48, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the bottom run of the track rises towards the leading
idler wheel.
73. The track assembly of claim 48, wherein the track assembly is
steerable by a steering mechanism of the vehicle to change an
orientation of the track assembly relative to the vehicle.
74. A set of four track assemblies for traction of a vehicle,
wherein each of at least two of the four track assemblies is as
claimed in claim 48.
75. A vehicle comprising the track assembly of claim 48.
76. The vehicle of claim 75, wherein the vehicle is an all-terrain
vehicle (ATV).
77. A track assembly for traction of a vehicle, the track assembly
comprising: a) a track comprising a ground-engaging outer side for
engaging the ground and an inner side opposite to the
ground-engaging outer side; and b) a track-engaging arrangement for
driving and guiding the track around the track-engaging
arrangement, a bottom run of the track extending under the
track-engaging arrangement, the track-engaging arrangement
comprising: i. a drive wheel for driving the track; and ii. a
plurality of guiding wheels contacting the bottom run of the track,
the plurality of guiding wheels including a leading idler wheel and
a trailing idler wheel spaced apart in a longitudinal direction of
the track assembly; wherein: a distance between an axis of rotation
of the drive wheel and an axis of rotation of the leading idler
wheel in the longitudinal direction of the track assembly is
different from a distance between the axis of rotation of the drive
wheel and an axis of rotation of the trailing idler wheel in the
longitudinal direction of the track assembly; and a given one of
the guiding wheels is resilient to be elastically deformable when
the track assembly moves on the ground.
78. A track assembly for traction of a vehicle, the track assembly
being steerable by a steering mechanism of the vehicle to change an
orientation of the track assembly relative to the vehicle, the
track assembly comprising: a) a track comprising a ground-engaging
outer side for engaging the ground and an inner side opposite to
the ground-engaging outer side; and b) a track-engaging arrangement
for driving and guiding the track around the track-engaging
arrangement, a bottom run of the track extending under the
track-engaging arrangement, the track-engaging arrangement
comprising: i. a drive wheel for driving the track; and ii. a
plurality of guiding wheels contacting the bottom run of the track;
wherein a given one of the guiding wheels is resilient to be
elastically deformable when the track assembly moves on the
ground.
79. A track assembly for traction of a vehicle, the track assembly
comprising: a) a track comprising a ground-engaging outer side for
engaging the ground and an inner side opposite to the
ground-engaging outer side; and b) a track-engaging arrangement for
driving and guiding the track around the track-engaging
arrangement, a bottom run of the track extending under the
track-engaging arrangement, the track-engaging arrangement
comprising: i. a drive wheel for driving the track; and ii. a
plurality of guiding wheels contacting the bottom run of the track;
wherein a given one of the guiding wheels comprises foam.
80. The track assembly of claim 79, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the given one of the guiding wheels is a given one of
the leading idler wheel and the trailing idler wheel.
81. The track assembly of claim 80, wherein the given one of the
leading idler wheel and the trailing idler wheel is the leading
idler wheel.
82. The track assembly of claim 81, wherein the trailing idler
wheel comprises foam.
83. The track assembly of claim 79, wherein: an axis of rotation of
the given one of the guiding wheels is movable relative to an axis
of rotation of the drive wheel when the track assembly moves on the
ground.
84. The track assembly of claim 79, wherein the plurality of
guiding wheels includes: a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and a plurality of support wheels disposed between the
leading idler wheel and the trailing idler wheel in the
longitudinal direction of the track assembly.
85. The track assembly of claim 84, wherein the given one of the
guiding wheels is a given one of the leading idler wheel and the
trailing idler wheel.
86. The track assembly of claim 79, wherein the foam is closed-cell
foam.
87. The track assembly of claim 86, wherein the closed-cell foam is
closed-cell polyurethane foam.
88. The track assembly of claim 79, wherein the foam forms at least
part of a periphery of the given one of the guiding wheels.
89. The track assembly of claim 84, wherein: the given one of the
guiding wheels is a given one of the leading idler wheel and the
trailing idler wheel; and an outer diameter of the given one of the
leading idler wheel and the trailing idler wheel is greater than an
outer diameter of a given one of the support wheels.
90. The track assembly of claim 84, wherein: the given one of the
guiding wheels is a given one of the leading idler wheel and the
trailing idler wheel; and the given one of the leading idler wheel
and the trailing idler wheel is wider than a given one of the
support wheels in a widthwise direction of the track assembly.
91. The track assembly of claim 89, wherein the given one of the
leading idler wheel and the trailing idler wheel is wider than the
given one of the support wheels in a widthwise direction of the
track assembly.
92. The track assembly of claim 80, wherein: the track-engaging
arrangement comprises a frame supporting the leading idler wheel
and the trailing idler wheel; and a width of the given one of the
leading idler wheel and the trailing idler wheel in a widthwise
direction of the track assembly occupies at least a majority of a
distance between a lateral surface of the given one of the leading
idler wheel and the trailing idler wheel and a center of the frame
in the widthwise direction of the track assembly.
93. The track assembly of claim 79, wherein: the inner side of the
track comprises a plurality of wheel-contacting projections for
contacting at least one of the drive wheel and the guiding wheels;
and a width of the given one of the guiding wheels in a widthwise
direction of the track assembly is greater than a dimension of a
given one of the wheel-contacting projections in the widthwise
direction of the track assembly.
94. The track assembly of claim 93, wherein the plurality of
wheel-contacting projections comprises a plurality of drive
projections and the drive wheel comprises a sprocket for engaging
the drive projections.
95. The track assembly of claim 79, wherein a radial extent of the
given one of the guiding wheels corresponding to at least 20% of an
outer radius of the given one of the guiding wheels is elastically
deformable when the track assembly moves on the ground.
96. The track assembly of claim 79, wherein the track-engaging
arrangement comprises a frame supporting the guiding wheels and
mounted about an axis of rotation of the drive wheel.
97. The track assembly of claim 79, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the track-engaging arrangement comprises a frame
supporting the guiding wheels and having a pivot point located
between the leading idler wheel and the trailing idler wheel in the
longitudinal direction of the track assembly.
98. The track assembly of claim 97, wherein the pivot point of the
frame corresponds to an axis of rotation of the drive wheel.
99. The track assembly of claim 79, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and a distance between an axis of rotation of the drive
wheel and an axis of rotation of the leading idler wheel in the
longitudinal direction of the track assembly is different from a
distance between the axis of rotation of the drive wheel and an
axis of rotation of the trailing idler wheel in the longitudinal
direction of the track assembly.
100. The track assembly of claim 79, wherein the inner side of the
track comprises a plurality of drive projections and the drive
wheel comprises a sprocket for engaging the drive projections.
101. The track assembly of claim 79, wherein: the plurality of
guiding wheels includes a leading idler wheel and a trailing idler
wheel spaced apart in a longitudinal direction of the track
assembly; and the bottom run of the track rises towards the leading
idler wheel.
102. The track assembly of claim 79, wherein the track assembly is
steerable by a steering mechanism of the vehicle to change an
orientation of the track assembly relative to the vehicle.
103. A set of four track assemblies for traction of a vehicle,
wherein each of at least two of the four track assemblies is as
claimed in claim 79.
104. A vehicle comprising the track assembly of claim 79.
105. The vehicle of claim 104, wherein the vehicle is an
all-terrain vehicle (ATV).
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation, and claims the benefit
under 35 U.S.C. 120, of U.S. patent application Ser. No. 12/767,895
filed on Apr. 27, 2010 and hereby incorporated by reference herein,
and claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional
Patent Application 61/173,627 filed on Apr. 29, 2009 and hereby
incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates generally to tracked vehicles and,
more particularly, to track assemblies for providing traction to
all-terrain vehicles (ATVs) or other tracked vehicles.
BACKGROUND
[0003] Tracked vehicles are often used on soft, low friction and/or
uneven ground, such as earth, mud, ice and/or snow, because of
their endless tracks which enhance their traction and floatation on
the ground.
[0004] As they travel on the ground, tracked vehicles can encounter
various obstacles (e.g., rocks, portions of trees, debris, ice
blocks, bumps or other abrupt changes in ground level, etc.)
depending on their environment. Such obstacles can create shocks in
track assemblies of the tracked vehicles. Depending on their
intensity, these shocks may affect ride quality and/or structural
integrity of the track assemblies. Also, while most obstacles
encountered by tracked vehicles are normally easily surmounted,
some obstacles may sometimes prove more difficult to overcome. This
can negatively impact a tracked vehicle's performance by slowing it
down or in some cases bringing it to a standstill.
[0005] For example, all-terrain vehicles (ATVs) propelled by track
assemblies may be prone to such problems when encountering
obstacles on the ground. For instance, in some situations, an ATV's
track assemblies may encounter large rocks, fallen tree portions,
or abrupt changes in ground level that induce shocks which can be
strongly felt by the ATV's rider. In other situations, an ATV may
encounter an obstacle such as a large rock, fallen tree portion or
abrupt change in ground level which is difficult to overcome by one
of its track assemblies (e.g., due to a tendency of a front region
of that track assembly to "dig" or "wedge" itself at the obstacle's
base instead of climbing over the obstacle).
[0006] Similar problems related to encountering of obstacles on the
ground can arise with other types of tracked vehicles.
[0007] Accordingly, there is a need for solutions directed to
facilitate use of ATVs and other tracked vehicles which are
susceptible to encountering obstacles on the ground.
SUMMARY OF THE INVENTION
[0008] According to one broad aspect, the invention provides a
track assembly for providing traction to an all-terrain vehicle
(ATV). The track assembly comprises: a drive wheel for driving an
endless track, the endless track having an inner side for facing
the drive wheel and a ground-engaging outer side for engaging the
ground, the drive wheel being rotatable about an axle of the ATV; a
plurality of support wheels for rolling on the inner side of the
endless track along a bottom run of the endless track, the support
wheels being distributed along a longitudinal direction of the
track assembly; and a resilient wheel for contacting the inner side
of the endless track such that a longitudinal end segment of the
endless track turns around the resilient wheel, the resilient wheel
being elastically deformable.
[0009] According to another broad aspect, the invention provides a
track assembly for providing traction to an all-terrain vehicle
(ATV). The track assembly comprises: a drive wheel for driving an
endless track, the endless track having an inner side for facing
the drive wheel and a ground-engaging outer side for engaging the
ground, the drive wheel being rotatable about an axle of the ATV;
and a plurality of wheels for contacting the inner side of the
endless track along a bottom run of the endless track, at least one
of the wheels being a resilient wheel, the resilient wheel being
elastically deformable.
[0010] According to another broad aspect, the invention provides a
track assembly for providing traction to an all-terrain vehicle
(ATV). The track assembly comprises: a drive wheel for driving an
endless track, the endless track having an inner side for facing
the drive wheel and a ground-engaging outer side for engaging the
ground, the drive wheel being rotatable about an axle of the ATV; a
plurality of support wheels for rolling on the inner side of the
endless track along a bottom run of the endless track, the support
wheels being distributed along a longitudinal direction of the
track assembly; and a wheel device for contacting the inner side of
the endless track such that a longitudinal end segment of the
endless track turns around the wheel device, the wheel device
allowing a change in curvature of the longitudinal end segment of
the endless track when the longitudinal end segment of the endless
track contacts an obstacle on the ground.
[0011] According to another broad aspect, the invention provides a
track assembly for providing traction to an all-terrain vehicle
(ATV). The track assembly comprises: a drive wheel for driving an
endless track, the endless track having an inner side for facing
the drive wheel and a ground-engaging outer side for engaging the
ground, the drive wheel being rotatable about an axle of the ATV; a
plurality of support wheels for rolling on the inner side of the
endless track along a bottom run of the endless track, the support
wheels being distributed along a longitudinal direction of the
track assembly; and a leading idler wheel located ahead of the
support wheels, the leading idler wheel comprising a tire; and a
trailing idler wheel located behind the support wheels, the
trailing idler wheel comprising a tire.
[0012] According to another broad aspect, the invention provides a
track assembly for providing traction to a tracked vehicle. The
track assembly comprises: a drive wheel for driving an endless
track, the endless track having an inner side for facing the drive
wheel and a ground-engaging outer side for engaging the ground, the
drive wheel being rotatable about an axle of the tracked vehicle; a
plurality of support wheels for rolling on the inner side of the
endless track along a bottom run of the endless track, the support
wheels being distributed along a longitudinal direction of the
track assembly; and a wheel device for contacting the inner side of
the endless track such that a longitudinal end segment of the
endless track turns around the wheel device, the wheel device
allowing a change in curvature of the longitudinal end segment of
the endless track when the longitudinal end segment of the endless
track contacts an obstacle on the ground.
[0013] These and other aspects of the invention will now become
apparent to those of ordinary skill in the art upon review of the
following description of embodiments of the invention in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] A detailed description of embodiments of the invention is
provided below, by way of example only, with reference to the
accompanying drawings, in which:
[0015] FIG. 1 shows a side view of a tracked vehicle in accordance
with an embodiment of the invention;
[0016] FIG. 2 shows a top view of the tracked vehicle of FIG.
1;
[0017] FIG. 3 shows a perspective view of a track assembly of the
tracked vehicle of FIG. 1;
[0018] FIG. 4 shows a side view of the track assembly of FIG.
3;
[0019] FIG. 5 shows a perspective view of the track assembly of
FIG. 3 with a track removed;
[0020] FIG. 6 shows a side view of the track assembly of FIG.
5;
[0021] FIG. 7 shows a top view of the track assembly of FIG. 5;
[0022] FIG. 8 shows an end view of the track assembly of FIG.
5;
[0023] FIG. 9 shows an example of a reaction of the track assembly
of FIG. 3 when encountering an obstacle on the ground;
[0024] FIG. 10 shows a side view of the tracked vehicle in
accordance with another embodiment of the invention;
[0025] FIG. 11 shows a top view of the tracked vehicle of FIG.
10;
[0026] FIG. 12 shows a perspective view of a track assembly of the
tracked vehicle of FIG. 10;
[0027] FIG. 13 shows a side view of the track assembly of FIG.
12;
[0028] FIG. 14 shows a perspective view of the track assembly of
FIG. 12 with a track removed;
[0029] FIG. 15 shows a side view of the track assembly of FIG.
14;
[0030] FIG. 16 shows a top view of the track assembly of FIG.
14;
[0031] FIG. 17 shows an end view of the track assembly of FIG.
14;
[0032] FIGS. 18 and 19 show components of a wheel device of the
track assembly of FIG. 12;
[0033] FIG. 20 shows an example of a reaction of the track assembly
of FIG. 12 when encountering an obstacle having a relatively small
size; and
[0034] FIG. 21 shows an example of a reaction of the track assembly
of FIG. 12 when encountering an obstacle having a relatively large
size.
[0035] It is to be expressly understood that the description and
drawings are only for the purpose of illustrating certain
embodiments of the invention and are an aid for understanding. They
are not intended to be a definition of the limits of the
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0036] FIGS. 1 and 2 show a tracked vehicle 10 in accordance with
an embodiment of the invention. More specifically, in this
embodiment, the tracked vehicle 10 is an all-terrain vehicle (ATV),
which is a small open vehicle designed to travel off-road on a
variety of terrains, including roadless rugged terrain, for
recreational, utility and/or other purposes.
[0037] In this embodiment, the ATV 10 comprises a prime mover 12, a
plurality of track assemblies 14.sub.1, 14.sub.2, 16.sub.1,
16.sub.2, a steering unit 20, and a seat 18, which enable a driver
of the ATV to ride the ATV 10 on the ground.
[0038] The prime mover 12 is a source of motive power that
comprises one or more motors (e.g., an internal combustion engine,
an electric motor, etc.). For example, in this embodiment, the
prime mover 12 comprises an internal combustion engine. In other
embodiments, the prime mover 12 may comprise another type of motor
(e.g., an electric motor) or a combination of different types of
motor (e.g., an internal combustion engine and an electric motor)
for generating motive power to move the ATV 10.
[0039] The prime mover 12 is in a driving relationship with one or
more of the track assemblies 14.sub.1, 14.sub.2, 16.sub.1,
16.sub.2. That is, motive power generated by the prime mover 12 is
transmitted to one or more of the track assemblies 14.sub.1,
14.sub.2, 16.sub.1, 16.sub.2 via a powertrain of the ATV 10.
[0040] In this case, the seat 18 is a straddle seat and the ATV 10
is usable by a single person such that the seat 18 accommodates
only the driver of the ATV 10. In other cases, the seat 18 may be
another type of seat, and/or the ATV 10 may usable by two
individuals, namely the driver and a passenger, such that the seat
18 may accommodate both the driver and the passenger (e.g., behind
one another or side-by-side) or the ATV 10 may comprise an
additional seat for the passenger.
[0041] The steering unit 20 enables the driver of the ATV 10 to
steer the ATV 10. In this case, the steering unit 20 comprises
handlebars. In other cases, the steering unit 20 may comprise a
steering wheel or other type of steering device.
[0042] The track assemblies 14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2
provide traction to the ATV 10 on the ground.
[0043] The track assemblies 16.sub.1, 16.sub.2 are located in a
rear part of the ATV 10 to provide traction in this rear part. With
additional reference to FIGS. 3 to 8, in this embodiment, each
track assembly 16.sub.i comprises a frame 44, a drive wheel 42, a
plurality of support wheels 50.sub.1-50.sub.8, a plurality of wheel
devices 54.sub.1-54.sub.4, and an endless track 41 disposed around
these wheels and wheel devices.
[0044] The track assembly 16.sub.i has a first longitudinal end 57
and a second longitudinal end 59 that define a length of the track
assembly 16.sub.i. A width of the track assembly 16.sub.i is
defined by a width of the endless track 41. The track assembly
16.sub.i has a longitudinal direction, transversal directions
including a widthwise direction, and a height direction.
[0045] The endless track 41 provides traction to propel the ATV 10
on the ground. The track 41 has an inner side 45 facing the wheels
42, 50.sub.1-50.sub.8 and the wheel devices 54.sub.1-54.sub.4 and
defining an inner area of the track 41 in which these wheels and
wheel devices are located. The track 41 also has a ground-engaging
outer side 47 opposite the inner side 45 and engaging the ground on
which the ATV 10 travels. In this embodiment, the inner side 45 of
the track 41 comprises a plurality of drive projections (sometimes
referred to as "drive lugs") that are spaced apart along the
longitudinal direction of the track assembly 16.sub.i and that
interact with the drive wheel 42 in order to cause the track 41 to
be driven. The ground-engaging outer side 27 comprises a plurality
of traction projections (sometimes referred to as "traction lugs"
or "traction profiles") that are spaced apart along the
longitudinal direction of the track assembly 16.sub.i and engage
the ground to enhance traction.
[0046] In this embodiment, the endless track 41 comprises an
elastomeric body, i.e., a body comprising elastomeric material,
which allows the track 41 to elastically change in shape as it is
in motion around the wheels 42, 50.sub.1-50.sub.8 and the wheel
devices 54.sub.1-54.sub.4. The elastomeric material can be any
polymeric material with the property of elasticity. In this
embodiment, the elastomeric material includes rubber. Various
rubber compounds may be used and, in some cases, different rubber
compounds may be present in different areas of the track 41. In
other embodiments, the elastomeric material may include another
elastomer in addition to or instead of rubber (e.g., polyurethane
elastomer). Also, in this embodiment, the track 41 comprises one or
more reinforcements embedded in the elastomeric material (e.g., a
layer of reinforcing longitudinal cables and/or a layer of
reinforcing fabric).
[0047] The track 41 may be constructed in various other manners in
other embodiments. For example, in some embodiments, the track 41
may comprise a plurality of parts (e.g., rubber and/or metallic
sections) interconnected to one another to form an endless belt,
the track 41 may have recesses or holes that interact with the
drive wheel 42 in order to cause the track 41 to be driven, and/or
the ground-engaging outer side 47 of the track 41 may comprise
various patterns of traction projections.
[0048] The endless track 41 has a top run, which extends between
and above the longitudinal ends 57, 59 of the track assembly
16.sub.i, and a bottom run, which extends between and below the
longitudinal ends 57, 59 of the track assembly 16.sub.i.
[0049] The drive wheel 42 is rotatable about an axle 49 of the ATV
10 for driving the track 41. That is, power generated by the
powertrain of the ATV 10 can rotate the axle 49, which rotates the
drive wheel 42, which imparts motion of the track 41. In this
embodiment, the drive wheel 42 comprises a drive sprocket engaging
the drive projections of the inner side 45 of the track 41 in order
to drive the track 41. In other embodiments, the drive wheel 42 may
be configured in various other ways. For example, in embodiments
where the track 41 comprises recesses or holes, the drive wheel 42
may have teeth that enter these recesses or holes in order to drive
the track 41. As yet another example, in some embodiments, the
drive wheel 42 may frictionally engage the inner side 45 of the
track 41 in order to frictionally drive the track 41.
[0050] The frame 44 supports various components of the track
assembly 16.sub.i, including the support wheels 50.sub.1-50.sub.8
and the wheel devices 54.sub.1-54.sub.4. More particularly, in this
embodiment, the frame 44 comprises three (3) frame elements
43.sub.1-43.sub.3 defining a generally triangular shape. Each of
the support wheels 50.sub.1-50.sub.8 and the wheel devices
54.sub.1-54.sub.4 is mounted to the frame element 43.sub.1.
Specifically, the wheel devices 54.sub.1, 54.sub.2 are mounted to
the frame element 43.sub.1 in a front longitudinal end region 89 of
the track assembly 16.sub.i, the wheel devices 54.sub.3, 54.sub.4
are mounted to the frame element 43.sub.1 in a rear longitudinal
end region 99 of the track assembly 16.sub.i, and the support
wheels 50.sub.1-50.sub.8 are mounted to the frame element 43.sub.1
in a bottom region of the track assembly 16.sub.i between the wheel
devices 54.sub.1-54.sub.4. Each of the support wheels
50.sub.1-50.sub.8 may be directly rotatably mounted to the frame
element 43.sub.1 or may be rotatably mounted to a link which is
rotatably mounted to the frame element 43.sub.1 and to which is
rotatably mounted an adjacent one of the support wheels
50.sub.1-50.sub.8, thus forming a "tandem". In other embodiments,
the frame 44 may be configured in various other manners.
[0051] In this embodiment, the frame 44 is pivotable about a pivot
point 51 to facilitate motion of the track assembly 16.sub.i on
uneven terrain and enhance its traction on the ground. More
specifically, in this case, the pivot point 51 corresponds to the
axle 49 on which the drive wheel 42 is mounted. The frame 44 is
pivotally connected at the pivot point 51 by the frame elements
43.sub.2, 43.sub.3 that converge towards this point. In this way,
the frame 44, and thus the track assembly 16.sub.i, can pivot about
the pivot point 51 to deal with uneven terrain the ATV 10 may
traverse. In other embodiments, the frame 44 may not be able to
pivot about any pivot point.
[0052] The support wheels 50.sub.1-50.sub.8 do not convert power
supplied by the prime mover 12 to motive force, but rather support
and distribute part of the weight of the ATV 10 on the ground as
well as guide the track 41 as it is driven by the drive wheel 42.
The support wheels 50.sub.1-50.sub.8 roll on the inner side 45 of
the track 41 along the bottom run of the track 41 to apply the
bottom run on the ground.
[0053] Each of the wheel devices 54.sub.1-54.sub.4 is a device
comprising at least one wheel. In this embodiment, the wheel device
54.sub.1 comprises a wheel 77.sub.1, the wheel device 54.sub.2
comprises a wheel 77.sub.2, the wheel device 54.sub.3 comprises a
wheel 77.sub.3, and the wheel device 54.sub.4 comprises a wheel
77.sub.4. The wheels 77.sub.1, 77.sub.2 are leading idler wheels,
and the wheels 77.sub.3, 77.sub.4 are trailing idler wheels. The
wheel devices 54.sub.1, 54.sub.2 are spaced apart along the
widthwise direction of the track assembly 16.sub.i, and so are the
wheel devices 54.sub.3, 54.sub.4.
[0054] The wheel devices 54.sub.1, 54.sub.2 are rotatable about
respective axes of rotation 78, 79. In this embodiment, the axes of
rotation 78, 79 are aligned with one another to constitute a common
axis of rotation 80. More specifically, in this example, the wheel
devices 54.sub.1, 54.sub.2 are rotatably mounted to the frame 44
via an axle 56 which provides the axis of rotation 80. In other
examples, the wheel devices 54.sub.1, 54.sub.2 may be mounted to
the frame 44 via respective axles which are aligned with one
another and which provide the axes of rotation 78, 79. In other
embodiments, the axis of rotation 78 and the axis of rotation 79
may be offset from one another.
[0055] Each of the wheel devices 54.sub.1, 54.sub.2 contacts the
inner side 45 of the endless track 41 such that a longitudinal end
segment 50 of the endless track 41 turns around that wheel device.
That is, each of the wheel devices 54.sub.1, 54.sub.2 contacts both
the top run of the endless track 41 and the bottom run of the
endless track 41 such that the longitudinal end segment 50 of the
endless track 41 includes a longitudinal end part of the top run of
the endless track 41 and a longitudinal end part of the bottom run
of the endless track 41. In this embodiment, the longitudinal end
segment 50 of the endless track 41 is located between the axis of
rotation 80 of the wheeled devices 54.sub.1, 54.sub.2 and the
longitudinal end 57 of the track assembly 16.sub.i. In embodiments
in which the axis of rotation 78 and the axis of rotation 79 are
offset from one another, the longitudinal end segment 50 of the
endless track 41 is located between the longitudinal end 57 of the
track assembly 16.sub.i and a given one of the axes of rotation 78,
79 which is closest to the longitudinal end 57 of the track
assembly 16.sub.i. Thus, in this example, the longitudinal end
segment 50 of the endless track 41 is that segment of the track 41
between points A.sub.1 and B.sub.1.
[0056] The wheel devices 54.sub.1, 54.sub.2 are leading wheel
devices that maintain the track 41 in tension, and can help to
support and distribute part of the weight of the ATV 10 on the
ground.
[0057] In addition, the wheel devices 54.sub.1-54.sub.4 facilitate
use of the ATV 10 when the ATV 10 encounters obstacles (e.g.,
rocks, portions of trees, debris, bumps, abrupt changes in ground
level, etc.) on the ground. For instance, each of the wheel devices
54.sub.1-54.sub.4 may absorb shocks when the track assembly
16.sub.i encounters obstacles on the ground and/or may make it
easier for the track assembly 16.sub.i to surmount obstacles on the
ground.
[0058] Each of the wheel devices 54.sub.1, 54.sub.2 allows a change
in curvature of the longitudinal end segment 50 of the endless
track 41 when the longitudinal end segment 50 of the endless track
41 contacts an obstacle on the ground. This may absorb a shock
resulting from contact with the obstacle and/or may make it easier
for the track assembly 16.sub.i to surmount the obstacle.
[0059] More particularly, in this embodiment, the wheels 77.sub.1,
77.sub.2 are resilient wheels which are elastically deformable.
That is, each of the resilient wheels 77.sub.1, 77.sub.2 can deform
under load and regain its original shape upon removal of the load.
When the longitudinal end segment 50 of the endless track 21
contacts an obstacle on the ground as the ATV 10 moves, one or both
of the resilient wheels 77.sub.1, 77.sub.2 can elastically deform
to allow a change in curvature of the longitudinal end segment 50
of the endless track 21. One or both of the resilient wheels
77.sub.1, 77.sub.2 can be compressed under load of the ATV 10 to
allow the longitudinal end segment 50 of the endless track 21 to
change in curvature in order to generally conform to a contacted
part of the obstacle. This elastic deformation of one or both of
the resilient wheels 77.sub.1, 77.sub.2 absorbs at least part of a
shock resulting from contact with the obstacle. Also, the change in
curvature of the longitudinal end segment 50 of the endless track
21 may enhance its traction on the obstacle and can thus facilitate
climbing of the track assembly 16.sub.i over the obstacle. As the
obstacle is surmounted and stress on one or both of the resilient
wheels 77.sub.1, 77.sub.2 that had been compressed is reduced, any
of the resilient wheels 77.sub.1, 77.sub.2 that had been compressed
can regain its original shape.
[0060] Each of the resilient wheels 77.sub.1, 77.sub.2 may be
elastically deformable to different radial extents in various
embodiments. For example, in some embodiments, a radial extent E
corresponding to at least 5%, in some cases at least 10%, in some
cases at least 15%, in some cases at least 20%, in some cases at
least 25%, in some cases at least 30%, in some cases at least 35%,
in some cases at least 40% of an outer radius R of each of the
resilient wheels 77.sub.1, 77.sub.2 may be elastically deformable.
In this case, the radial extent E of each of the resilient wheels
77.sub.1, 77.sub.2 that is elastically deformable corresponds to
about 50% of the outer radius R of that wheel. In some embodiments,
an entirety of the resilient wheel may be elastically
deformable.
[0061] The resilient wheels 77.sub.1, 77.sub.2 may be compressible
radially by different degrees in various embodiments. For example,
in some embodiments, each of the resilient wheels 77.sub.1,
77.sub.2 may be compressible radially in use (i.e., under loads
expected to be experienced when the track assembly 16.sub.i
encounters obstacles on the ground) by at least 5%, in some cases
by at least 10%, in some cases by at least 15%, in some cases by at
least 20%, in some cases by at least 25%, in some cases by at least
30%, in some cases by at least 35%, and in some cases by at least
40% of its outer radius R. For instance, in an embodiment where
each of the resilient wheels 77.sub.1, 77.sub.2 has an outer radius
of 130 mm, each of these resilient wheels may be capable of
compressing itself radially by at least 65 mm (i.e., 50%). The
actual degree of compression of a given one of the resilient wheels
77.sub.1, 77.sub.2 when the track assembly 16.sub.i encounters an
obstacle will depend on the nature of the obstacle (e.g., its
shape, material, etc.) and the load exerted on that wheel by the
ATV 10.
[0062] In this embodiment, each of the resilient wheels 77.sub.1,
77.sub.2 comprises a hub 75 and a deformable wheel portion 58
around the hub 75. The hub 75 is rigid and rotatable about the axle
56. For example, the hub 75 may comprise one or more parts made of
rigid metal, plastic, and/or composite material.
[0063] The deformable wheel portion 58 may constitute a tire. For
instance, in this case, the deformable wheel portion 58 constitutes
a non-pneumatic tire (i.e., an airless tire). More particularly, in
this case, the deformable wheel portion 58 is made of foam such
that the resilient wheel 77.sub.i is a foam wheel (i.e., a wheel at
least partly made of foam). The foam is elastically deformable such
that it can deform under load and regain its original shape when
the load is removed. Various types of foam may be used. For
example, in some embodiments, the foam may be polymeric foam (e.g.,
closed-cell polymeric foam). For instance, in some cases, the foam
may be polyurethane foam.
[0064] As shown in FIGS. 4 to 9, in this embodiment, an outer
diameter of each of the resilient wheels 77.sub.1, 77.sub.2 is
greater than an outer diameter of each of the support wheels
50.sub.1-50.sub.8. Each of the resilient wheels 77.sub.1, 77.sub.2
is wider than each of the support wheels 50.sub.1-50.sub.8 in the
widthwise direction of the track assembly 16.sub.i.
[0065] A shown in FIGS. 7 and 8, in this embodiment, the resilient
wheels 77.sub.1, 77.sub.2 collectively occupy a majority of a span
of the resilient wheels 77.sub.1, 77.sub.2 in the widthwise
direction of the track assembly 16.sub.i. As shown in FIG. 3, in
this embodiment, the width of a resilient wheel 77.sub.i in the
widthwise direction of the track assembly 16.sub.i is greater than
a dimension of a drive projection of the inner side 45 of the track
41 in the widthwise direction of the track assembly 16.sub.i.
[0066] The resilient wheels 77.sub.1, 77.sub.2 may be implemented
in various other ways in other embodiments. For example, in some
embodiments, each of the resilient wheels 77.sub.1, 77.sub.2 may
comprise elastic material other than foam (e.g., rubber or other
elastomeric material), which is capable of deforming itself under
load and then regaining its original shape upon removal of the
load. As another example, in some embodiments, each of the
resilient wheels 77.sub.1, 77.sub.2 may comprise a pneumatic
tire.
[0067] The wheel devices 54.sub.3, 54.sub.4 are configured in a
manner similar to the wheel devices 54.sub.1, 54.sub.2. Each of the
wheel devices 54.sub.3, 54.sub.4 contacts the inner side 45 of the
endless track 41 such that a longitudinal end segment 32 of the
endless track 41 turns around that wheeled device. The longitudinal
end segment 32 of the endless track 41 is located between an axis
of rotation of the wheel devices 54.sub.3, 54.sub.4 and the
longitudinal end 59 of the track assembly 16.sub.i. Thus, in this
example, the longitudinal end segment 32 of the endless track 41 is
that segment of the track 41 between points A.sub.2 and
B.sub.2.
[0068] Each of the wheel devices 54.sub.3, 54.sub.4 allows a change
in curvature of the longitudinal end segment 32 of the endless
track 41 when the longitudinal end segment 32 of the endless track
41 contacts an obstacle on the ground. This may absorb a shock
resulting from contact with the obstacle and/or may make it easier
for the track assembly 16.sub.i to surmount the obstacle. More
particularly, in this embodiment, the wheels 77.sub.3, 77.sub.4 are
resilient wheels which are elastically deformable, as discussed
above in respect of the wheels 77.sub.1, 77.sub.2.
[0069] As shown in FIGS. 4 to 7, in this embodiment, a distance
between the axis of rotation of the drive wheel 42 and the axis of
rotation of the leading idler wheels 77.sub.1, 77.sub.2 in the
longitudinal direction of the track assembly 16.sub.i is different
from a distance between the axis of rotation of the drive wheel 42
and the axis of rotation of the trailing idler wheels 77.sub.3,
77.sub.4 in the longitudinal direction of the track assembly
16.sub.i.
[0070] The track assemblies 14.sub.1, 14.sub.2 are located in a
front part of the ATV 10 to provide traction in this front part.
Each track assembly 14.sub.i comprises a track 21, a drive wheel
22, a frame 24, a plurality of support wheels 30.sub.1-30.sub.6,
and a plurality of wheel devices 53.sub.1-53.sub.4. These
components of the track assembly 14.sub.i are respectively similar
in construction and function to the track 41, the drive wheel 42,
the frame 44, the support wheels 50.sub.1-50.sub.8, and the wheel
devices 54.sub.1-54.sub.4 and will therefore not be further
discussed.
[0071] With reference now to FIG. 9, there will be described an
example illustrating how the wheel devices 53.sub.1-53.sub.4,
54.sub.1-54.sub.4 of the track assemblies 14.sub.1, 14.sub.2,
16.sub.1, 16.sub.2 may absorb shocks resulting from contact with
obstacles on the ground and/or may make it easier for the track
assemblies 14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 to surmount such
obstacles.
[0072] Although obstacles (e.g., rocks, portions of trees, debris,
bumps, abrupt changes in ground level, etc.) come in a variety of
different shapes and sizes, they may all conceptually be viewed,
from the perspective of the ATV 10, as representing a variation in
ground level, namely a variation between a first ground level just
prior to the obstacle and a second ground level corresponding to a
top part of the obstacle. For example, a large, irregularly shaped
rock can be viewed as representing a variation between a first
ground level at a base of the rock and a second ground level
corresponding to the highest point of the rock.
[0073] Every obstacle can also be viewed as having a steepness that
can influence a degree to which it can be easily or not easily
overcome. For example, when viewing an obstacle as a variation
between two ground levels, the steepness of the obstacle can be
viewed as corresponding to the slope of a line following or tangent
to the general profile of the obstacle between these two ground
levels. This slope, which will hereinafter be referred to as the
"general slope" of the obstacle, may affect how the wheel devices
54.sub.1-54.sub.4, 53.sub.1-53.sub.4 of the track assemblies
14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 react to the obstacle in
question.
[0074] FIG. 9 shows an example of the result of an encounter
between the longitudinal end segment 50 of the endless track 41 of
the track assembly 16.sub.i and an obstacle 68 on the ground. In
this example, it is assumed that the obstacle 68 lying in the path
of the ATV 10 is a rock. It is further assumed that the ATV 10 was
in motion along level ground and that the track assemblies
14.sub.1, 14.sub.2 in the front part of the ATV 10 have already
cleared the rock 68 which is now lying directly ahead of the track
assemblies 16.sub.1, 16.sub.2 in the rear part of the ATV 10.
[0075] Up until the track assembly 16.sub.i contacts the rock 68,
the wheel devices 54.sub.1, 54.sub.2 is in a state as illustrated
in FIGS. 1 and 4, namely as it is when the ATV 10 is travelling
along a level ground surface. In particular, the resilient wheels
77.sub.1, 77.sub.2 have a generally non-deformed circular shape.
The track 41 thus has a curvature as shown in FIGS. 1 and 4, where
the longitudinal end segment 50 of the track 41 has a convexity
which generally corresponds to that of a circular arc defined by
the generally non-deformed circular shape of the resilient wheels
77.sub.1, 77.sub.2.
[0076] When the longitudinal end segment 50 of the endless track 41
of the track assembly 16.sub.i contacts the rock 68, one or both of
the wheel devices 54.sub.1, 54.sub.2 react to this contact. More
particularly, in this example, under load of the ATV 10, the
resilient wheels 77.sub.1, 77.sub.2 are compressed to allow the
longitudinal end segment 50 of the track 41 to change in curvature
in order to generally conform to a part of the rock 68 that is
engaged by the track 41. Specifically, the compression of the
resilient wheels 77.sub.1, 77.sub.2 induces a change in curvature
of the longitudinal end segment 50 of the track 41. This change in
curvature of the longitudinal end segment 50 of the track 41 allows
it to generally conform to the general slope of the rock 68. In
this case, the change in curvature is such that the portion of the
track 41 contacting the compressed section of the resilient wheels
77.sub.1, 77.sub.2 is oriented generally upwardly and forwardly at
an angle corresponding generally to the general slope of the rock
68. At that point, the longitudinal end segment 50 of the track 41
is more convex than it was prior to the track assembly 16.sub.i
contacting the rock 68. This elastic deformation of one or both of
the resilient wheels 77.sub.1, 77.sub.2 absorbs at least part of a
shock resulting from contact with the rock 68. Also, the change in
shape of the track 41 thus enhances its traction on the rock 68 and
thus facilitates climbing of the track assembly 16.sub.i over the
rock 68.
[0077] As the track assembly 16.sub.i reaches the top part of the
rock 68 and then moves down the rock 68, stress on the resilient
wheels 77.sub.1, 77.sub.2 is reduced causing each of the resilient
wheels 77.sub.1, 77.sub.2 to regain its original shape. In turn,
this causes the longitudinal end segment 50 of the track 41 to
regain its original curvature. Upon having cleared the rock 68, the
track assembly 16.sub.i continues to operate in the state as shown
in FIGS. 1 and 4.
[0078] It will thus be appreciated that the wheel devices
53.sub.1-53.sub.4, 54.sub.1-54.sub.4 of the track assemblies
14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 allows the ATV 10 to absorb
shocks resulting from contact with obstacles on the ground and/or
allows the ATV 10 to more easily overcome such obstacles. In
particular, by allowing a change in curvature of a longitudinal end
segment of its endless track, each of the track assemblies
14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 allows that segment of the
track \ to generally conform to an encountered obstacle. In other
words, each of the track assemblies 14.sub.1, 14.sub.2, 16.sub.1,
16.sub.2 provides a way to change the shape of a longitudinal end
segment of its endless track based on the size and shape of the
obstacle encountered. This local elastic deformation of the track
may absorb the shock resulting from contact with the obstacle. This
local elastic deformation may also allow more of its
ground-engaging side 47 to come into contact with the obstacle,
thus providing an increased surface area that can allow the track
assembly 14.sub.i, 16.sub.i to more easily climb over the obstacle.
This is useful for obstacles of various shapes and sizes, but
especially for those obstacles that would otherwise present
problems for a traditional idler wheel. For example, once the track
assemblies 14.sub.1, 14.sub.2 have cleared an obstacle such that
the obstacle is now located between the track assemblies 14.sub.1,
14.sub.2 and the track assemblies 16.sub.1, 16.sub.2, the obstacle
surmounting device 54.sub.1 of each of the track assemblies
16.sub.1, 16.sub.2 can make it easier for the track assemblies
16.sub.1, 16.sub.2 to overcome the obstacle than it would otherwise
if the track assemblies 16.sub.1, 16.sub.2 had, instead of their
respective obstacle surmounting device 54.sub.1, one or more
traditional idler wheels that could have certain difficulty in
overcoming the obstacle, for instance, due to a tendency of a front
region of that track assembly to "dig" or "wedge" itself at the
obstacle's base instead of climbing over the obstacle.
[0079] While in this embodiment the track assemblies 14.sub.1,
14.sub.2, 16.sub.1, 16.sub.2 are configured in a particular way,
they may be configured in various other ways in other
embodiments.
[0080] For example, in some embodiments, the track assembly
14.sub.i, 16.sub.i may comprise more or less than two resilient
wheels (such as the resilient wheels 77.sub.1-77.sub.4) adjacent to
each of its longitudinal ends. For instance, in some embodiments,
the track assembly 14.sub.i, 16.sub.i may comprise a single
resilient wheel or three or more resilient wheels adjacent to each
of its longitudinal ends.
[0081] As another example, in some embodiments, one or more of the
support wheel 50.sub.1-50.sub.8 may be resilient wheels that are
elastically deformable as discussed above in connection with the
resilient wheels 77.sub.1-77.sub.4. For instance, in some cases,
one or more of the support wheel 50.sub.1-50.sub.8 may be resilient
wheels similar in construction to, but smaller than, the resilient
wheels 77.sub.1-77.sub.4
[0082] As yet another example, instead of having wheel devices
53.sub.i, 54.sub.i positioned in respective front and rear
longitudinal end regions 89, 99 of the track assembly 14.sub.i,
16.sub.i, in some embodiments, the track assembly 14.sub.i,
16.sub.i may comprise wheel devices 53.sub.i, 54.sub.i only in one
of its front and rear longitudinal end regions. In such
embodiments, one or more conventional rigid idler wheels may be
provided in the longitudinal end region of the track assembly
14.sub.i, 16.sub.i where there is no wheel device 53.sub.i,
54.sub.i.
[0083] Although in this embodiment each of the track assemblies
14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 comprises wheel devices
53.sub.i, 54.sub.i, in other embodiments, some of the track
assemblies 14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 may not comprise
any such wheel device 53.sub.i, 54.sub.i.
[0084] Turning now to FIGS. 10 and 11, there is shown another
embodiment in which the ATV 10 comprises track assemblies
14'.sub.1, 14'.sub.2, 16'.sub.1, 16'.sub.2, instead of the track
assemblies 14.sub.1, 14.sub.2, 16.sub.1, 16.sub.2 discussed
previously.
[0085] The track assemblies 14'.sub.1, 14'.sub.2 are located in a
front part of the ATV 10 to provide traction in this front part.
Each track assembly 14'.sub.i comprises a track 21', a drive wheel
22', a frame 24', a pair of front idler wheels 26.sub.1, 26.sub.2
(which are laterally spaced apart, with only the idler wheel
26.sub.1 being visible in FIG. 10), a pair of rear idler wheels
28.sub.1, 28.sub.2 (which are laterally spaced apart, with only the
idler wheel 28.sub.1 being visible in FIG. 10), and a plurality of
support wheels 30'.sub.1-30'.sub.8 located longitudinally between
these front and rear idler wheels.
[0086] The track 21', the drive wheel 22', the frame 24' and the
support wheels 30'.sub.1-30'.sub.8 of the track assembly 14'.sub.i
are respectively similar in construction and function to the track
21, the drive wheel 22, the frame 24, and the support wheels
30.sub.1-30.sub.6 of the track assembly 14.sub.i discussed
previously.
[0087] The front idler wheels 26.sub.1, 26.sub.2 are rotatably
mounted to the frame 24' in a front longitudinal end region 37' of
the track assembly 14'.sub.1, while the rear idler wheels 28.sub.1,
28.sub.2 are rotatably mounted to the 24' in a rear longitudinal
end region 39' of the track assembly 14'.sub.i. However, in
contrast to the resilient wheels of the wheel devices
53.sub.1-53.sub.4 of the track assembly 14.sub.i, the front idler
wheels 26.sub.1, 26.sub.2 and the rear idler wheels 28.sub.1,
28.sub.2 are rigid wheels which do not elastically deform under
load of the ATV 10 to induce a change in curvature of the track
21.
[0088] The track assemblies 16'.sub.1, 16'.sub.2 are located in a
rear part of the ATV 10 to provide traction in this rear part. Each
track assembly 16', comprises a track 41', a drive wheel 42', a
frame 44', a pair of rear idler wheels 48.sub.1, 48.sub.2, a
plurality of support wheels 50'.sub.1-50'.sub.10, and a pair of
wheel devices 54'.sub.1, 54'.sub.2.
[0089] The track 41', the drive wheel 42', the frame 44' and the
support wheels 50'.sub.1-50'.sub.8 of the track assembly 16'.sub.i
are respectively similar in construction and function to the track
41, the drive wheel 42, the frame 44, and the support wheels
50.sub.1-50.sub.8 of the track assembly 16.sub.i discussed
previously.
[0090] The rear idler wheels 48.sub.1, 48.sub.2 roll on the inner
side 45' of the track 41' such that the longitudinal end segment
32' of the track 41' turns around these wheels. Like the rear idler
wheels 28.sub.1, 28.sub.2 of the track assembly 14'.sub.1, the rear
idler wheels 48.sub.1, 48.sub.2 are rigid wheels which do not
elastically deform under load of the ATV 10 to induce a change in
curvature of the track 41'.
[0091] Each of the wheel devices 54'.sub.1, 54'.sub.2 is a device
comprising at least one wheel. In this embodiment, the wheel device
54'.sub.1 comprises a wheel carrier 60 and three carried wheels
62.sub.1-62.sub.3 rotatably mounted to the wheel carrier 60, and
the wheel device 54'.sub.2 comprises a wheel carrier 64 and three
carried wheels 66.sub.1-66.sub.3 rotatably mounted to the wheel
carrier 64.
[0092] The wheel devices 54'.sub.1, 54'.sub.2 are rotatable about
respective axes of rotation 61, 67. In this embodiment, the axes of
rotation 61, 67 are aligned with one another to constitute a common
axis of rotation 87. More specifically, in this example, the wheel
devices 54'.sub.1, 54'.sub.2 are rotatably mounted to the frame 44'
via an axle 34 which provides the axis of rotation 87. In other
examples, the wheel devices 54'.sub.1, 54'.sub.2 may be mounted to
the frame 44' via respective axles which are aligned with one
another and which provide the axes of rotation 61, 67. In other
embodiments, the axis of rotation 61 and the axis of rotation 67
may be offset from one another.
[0093] Each of the wheel devices 54'.sub.1, 54'.sub.2 contacts the
inner side 45 of the endless track 41' such that a longitudinal end
segment 50' of the endless track 41' turns around that wheel
device. That is, each of the wheel devices 54'.sub.1, 54'.sub.2
contacts both the top run of the endless track 41' and the bottom
run of the endless track 41' such that the longitudinal end segment
50' of the endless track 41' includes a longitudinal end part of
the top run of the endless track 41' and a longitudinal end part of
the bottom run of the endless track 41'. In this embodiment, the
longitudinal end segment 50' of the endless track 41' is located
between the axis of rotation 87 of the wheel devices 54'.sub.1,
54'.sub.2 and the longitudinal end 57' of the track assembly
16'.sub.i. In embodiments in which the axis of rotation 61 and the
axis of rotation 67 are offset from one another, the longitudinal
end segment 50' of the endless track 41' is located between the
longitudinal end 57' of the track assembly 16'.sub.i and a given
one of the axes of rotation 61, 67 which is closest to the
longitudinal end 57' of the track assembly 16'.sub.i. Thus, in this
example, the longitudinal end segment 50' of the endless track 41'
is that segment of the track 41' between points A.sub.1' and
B.sub.1'.
[0094] Each of the wheel devices 54'.sub.1, 54'.sub.2 allows a
change in curvature of the longitudinal end segment 50' of the
endless track 41' when the longitudinal end segment 50' of the
endless track 41' contacts an obstacle on the ground. This may
absorb a shock resulting from contact with the obstacle and/or may
make it easier for the track assembly 16'.sub.i to surmount the
obstacle.
[0095] With respect to the wheel device 54'.sub.1, the wheel
carrier 60 is rotatably mounted to the frame 44' and adapted to
turn about the axis 61. The carried wheels 62.sub.1-62.sub.3 are
mounted to the wheel carrier 60 and able to rotate about respective
axes of rotation. In this embodiment, the carried wheels
62.sub.1-62.sub.3 are disposed around the axis 61 (i.e., a closed
imaginary line connecting their respective axes of rotation
surrounds the axis 61).
[0096] More particularly, in this embodiment, the wheel carrier 60
comprises three arms 65.sub.1-65.sub.3 that extend radially outward
from the axis 61. In this case, the arms 65.sub.1-65.sub.3 have the
same length and are spaced at equal angles from one another. In
other embodiments, the wheel carrier 60 may be configured in
various other ways. For example, in some embodiments, instead of
being a unitary structural element, the wheel carrier 60 may
comprise two or more separate structural elements each carrying one
or more of the carried wheels 62.sub.1-62.sub.3 (e.g., three links
each individually mounted to a common axle forming the axis 61 and
each carrying one of the carried wheels 62.sub.1-62.sub.3).
[0097] Each of the carried wheels 62.sub.1-62.sub.3 is mounted to
an axle on the wheel carrier 60 that defines the axis of rotation
of that carried wheel. Specifically, in this embodiment, the
carried wheel 62.sub.1 is rotatably mounted to the arm 65.sub.1,
the carried wheel 62.sub.2 is rotatably mounted to the arm
65.sub.2, and the carried wheel 62.sub.3 is rotatably mounted to
the arm 65.sub.3. The carried wheels 62.sub.1-62.sub.3 are thus
arranged in a triangular configuration, their respective axes of
rotation defining a triangle in which is located the axis 61 about
which the wheel carrier 60 can turn.
[0098] Each of the carried wheels 62.sub.1-62.sub.3 may rotate
about its respective axis of rotation independently of the wheel
carrier 60. When the wheel carrier 60 turns about the axis 61, the
carried wheels 62.sub.1-62.sub.3 (which are mounted to the member
60) turn about the axis 61 and may also rotate about their
respective axes of rotation.
[0099] More specifically, in this embodiment, when the ATV 10 is in
motion along a ground surface that is free of obstacles, the
carried wheels 62.sub.1-62.sub.3 roll on the inner side 45' of the
track 41' by rotating about their respective axes of rotation.
During this time, the wheel carrier 60 and the carried wheels
62.sub.1-62.sub.3 may be positioned such as shown in FIG. 13, where
the carried wheels 62.sub.2 and 62.sub.3 are generally aligned with
the support wheels 50'.sub.1-50'.sub.5, while the carried wheel
62.sub.1 lies above the support wheels 50'.sub.1-50'.sub.5. Also,
in this position, the carried wheels 62.sub.2 and 62.sub.3 are
positioned such that their respective axes of rotation lie slightly
below the axis 61 while the carried wheel 62.sub.1 is positioned
such that its axis of rotation lies above the axis 61. As a result,
the wheel carrier 60 and the carried wheels 62.sub.1-62.sub.3
impart a given curvature to the longitudinal end segment 50' of the
endless track 41'. This given curvature is such that the
longitudinal end segment 50' of the endless track 41' has a certain
convexity, which in this case is useful for travelling along a
level ground surface as it maximizes the contact area between the
track 41' and the level ground surface.
[0100] When the longitudinal end segment 50' of the endless track
41' comes into contact with an obstacle on the ground, the wheel
carrier 60 turns about the axis 61 to allow the track assembly
16'.sub.i to overcome the obstacle. Specifically, because the
carried wheels 62.sub.1-62.sub.3 are rotatably mounted to the wheel
carrier 60, they also turn about the axis 61 when the wheel carrier
60 turns. As the carried wheels 62.sub.1-62.sub.3 roll on the inner
side 45' of the track 41', this turning motion of the wheel carrier
60 and the carried wheels 62.sub.1-62.sub.3 about the axis 61
induces a change in curvature of the longitudinal end segment 50'
of the endless track 41'. This motion of the wheel carrier 60 and
the carried wheels 62.sub.1-62.sub.3 can absorb at least part of a
shock resulting from contact with the obstacle. Also, the change in
curvature of the longitudinal end segment 50' of the endless track
41' allows that segment of the track 41' to generally conform to
the obstacle being encountered and can facilitate its
surmounting.
[0101] While it can rotate about the axis of rotation 61, the wheel
device 54'.sub.1 may be configured such that, in use, it does not
necessarily make a complete rotation (i.e., a 360.degree. rotation)
about the axis 61. This is in contrast to the wheel devices
54.sub.1-54.sub.4, 53.sub.1-53.sub.4 discussed previously which, in
use, make complete rotations about their respective axes of
rotation.
[0102] The wheel device 54'.sub.2 is spaced apart from the wheel
device 54'.sub.1 along the widthwise direction of the track
assembly 16.sub.i. The wheel carrier 64 is rotatably mounted to the
frame 44' and adapted to turn about the axis 67. The carried wheels
66.sub.1-66.sub.3 are mounted to the wheel carrier 64 and able to
rotate about respective axes of rotation. In this embodiment, the
carried wheels 66.sub.1-66.sub.3 are disposed around the axis 67
(i.e., an imaginary closed line connecting their respective axes of
rotation surrounds the axis 67).
[0103] More particularly, in this embodiment, analogously to the
wheel carrier 60 and the carried wheels 62.sub.1-62.sub.3, the
wheel carrier 64 comprises three arms 69.sub.1-69.sub.3 that extend
radially outward from the axis 67, with the carried wheels
66.sub.1-66.sub.3 being rotatably mounted to respective ones of the
arm 69.sub.1-69.sub.3. Thus, each of the carried wheels
66.sub.1-66.sub.3 may rotate about its respective axis of rotation
independently of the wheel carrier 64, and, when the wheel carrier
64 turns about the axis 67, the carried wheels 66.sub.1-66.sub.3
turn about the axis 67 and may also rotate about their respective
axes of rotation.
[0104] With reference now to FIGS. 20 and 21, there will be
described examples illustrating how the wheel devices 54'.sub.1,
54'.sub.2 of the track assembly 16'.sub.i operate when the ATV 10
encounters obstacles on the ground.
[0105] As will be discussed, in this embodiment, the general slope
of an encountered obstacle affects how the wheel devices 54'.sub.1,
54'.sub.2 of the track assembly 16'.sub.i may react to the
obstacle. In particular, when the general slope of the obstacle is
not at a relatively steep angle, the wheel devices 54'.sub.1,
54'.sub.2 may react in a first manner by turning about their axes
61, 67 in a clockwise direction. For example, if the wheel devices
54'.sub.1, 54'.sub.2 encounter a relatively small bump on the
ground, they may react in this first manner. In contrast, when the
general slope of the obstacle is relatively steep, wheel devices
54'.sub.1, 54'.sub.2 may react in a second, different manner by
turning about their axes 61, 67 in a counterclockwise direction.
For example, if the ATV 10 is required to overcome a relatively
large, irregularly shaped rock, the wheel devices 54'.sub.1,
54'.sub.2 may react in this second manner.
[0106] FIG. 20 shows an example of the result of an encounter
between the wheel devices 54'.sub.1, 54'.sub.2 of the track
assembly 16'.sub.i and an obstacle 71 having a relatively small
size. In this example, it is assumed that the obstacle 71 lying in
the path of the ATV 10 is a portion of the trunk of a relatively
small tree having fallen on the ground. It is further assumed that
the ATV 10 was in motion along level ground and that the track
assemblies 14'.sub.1, 14'.sub.2 in the front part of the ATV 10
have already cleared the trunk portion 71 which is now lying
directly ahead of the track assemblies 16'.sub.1, 16'.sub.2 in the
rear part of the ATV 10.
[0107] Up until the track assembly 16'.sub.i contacts the trunk
portion 71, the various components of the wheel devices 54'.sub.1,
54'.sub.2 are positioned as illustrated in FIGS. 10 and 13, namely
as they are when the ATV 10 is travelling along a level ground
surface. More specifically, the wheel carriers 60, 64 are in an
angular position where: each of the carried wheels 62.sub.1,
66.sub.1 lies above the axis 61, 67; each of the carried wheels
62.sub.2, 66.sub.2, 62.sub.3, 66.sub.3 is in a vertical position
that is generally below the carried wheels 62.sub.1, 66.sub.1; and
the carried wheels 62.sub.3, 66.sub.3 are located longitudinally in
front of the carried wheels 62.sub.2, 66.sub.2.
[0108] When the longitudinal end segment 50' of the endless track
41' contacts the trunk portion 71 at a contact point, the wheel
devices 54'.sub.1, 54'.sub.2 react to this contact. In this
example, the general slope of the trunk portion 71 may be seen as
being relatively shallow. The general slope of the trunk portion 71
determines where the contact point between the trunk portion 71 and
the track 41' may occur, which determines the manner in which the
wheel devices 54'.sub.1, 54'.sub.2 react to the trunk portion 71.
In this case, the gentle angle of the general slope causes the
track 41' to contact the trunk portion 71 at a location on the
track 41' that is generally longitudinally aligned with a lower
portion of each of the carried wheels 62.sub.3, 66.sub.3 (i.e., a
portion below its respective axis of rotation). As a result, the
carried wheels 62.sub.3, 66.sub.3 are forced upwards and, as they
are mounted to the wheel carriers 60, 64, they cause the wheel
carriers 60, 64 to turn about the axis 61, 67 in a clockwise
direction.
[0109] This turning motion of the wheel carriers 60, 64 in a
clockwise direction adjusts the angular position of each of the
carried wheels 62.sub.1, 66.sub.1, 62.sub.2, 66.sub.2.
Specifically, in this case, this turning motion causes each of the
carried wheels 62.sub.1, 66.sub.1 to follow an arc to a new angular
position that may be vertically lower than and rearward of its
original position, while it causes each of the carried wheels
62.sub.2, 66.sub.2 to move slightly lower and forwardly of its
original position.
[0110] The wheel carriers 60, 64 and the carried wheels
62.sub.1-62.sub.3, 66.sub.1-66.sub.3 turning about the axis 61, 67
induces a change in curvature of the longitudinal end segment 50'
of the endless track 41'. In particular, the change in curvature of
the longitudinal end segment 50' of the endless track 41' allows
that segment of the track 41' to generally conform to the general
slope of the trunk portion 71 and can facilitate its surmounting.
Indeed, in this example, the change in curvature is such that the
portion of the track 41' between the carried wheels 62.sub.3,
66.sub.3 and the carried wheels 62.sub.2, 66.sub.2 is oriented
generally upwardly and forwardly at an angle corresponding
generally to the general slope of the trunk portion 71.
[0111] In this example, upon reaching the top part of the trunk
portion 71, the wheel devices 54'.sub.1, 54'.sub.2 proceed to go
down the trunk portion 71 and return to the first ground level. In
this case, the wheel devices 54'.sub.1, 54'.sub.2 operate in a
manner reverse to that previously described. In particular, as the
carried wheels 62.sub.3, 66.sub.3 follow a general downward slope
of the trunk portion 71 to return to the first ground level, they
are forced downwards and thus cause the wheel carriers 60, 64 to
turn about the axis 61, 67 in a counterclockwise direction. This
turning motion of the wheel carriers 60, 64 in a counterclockwise
direction adjusts the angular position of each of the carried
wheels 62.sub.1, 66.sub.1, 62.sub.2, 66.sub.2.
[0112] Once the wheel devices 54'.sub.1, 54'.sub.2 have cleared the
trunk portion 71, the wheel carriers 60, 64 and the carried wheels
62.sub.1-62.sub.3, 66.sub.1-66.sub.3 return to their original
positions as shown in FIGS. 10 and 13.
[0113] FIG. 21 shows an example of the result of an encounter
between the wheel devices 54'.sub.1, 54'.sub.2 of the track
assembly 16'.sub.i and an obstacle 73 having a relatively large
size. In this example, it is assumed that the obstacle 73 lying in
the path of the ATV 10 is a rock having a relatively large size. It
is further assumed that the ATV 10 was in motion along level ground
and that the track assemblies 14'.sub.1, 14'.sub.2 in the front
part of the ATV 10 have already cleared the rock 73 which is now
lying directly ahead of the track assemblies 16'.sub.1, 16'.sub.2
in the rear part of the ATV 10.
[0114] Up until the track assembly 16'.sub.i contacts the rock 73,
the various components of the wheel devices 54'.sub.1, 54'.sub.2
are positioned as illustrated in FIGS. 10 and 13, namely as they
are when the ATV 10 is travelling along a level ground surface.
More specifically, the wheel carriers 60, 64 are in an angular
position where: each of the carried wheels 62.sub.1, 66.sub.1 lies
above the axis 61, 67; each of the carried wheels 62.sub.2,
66.sub.2, 62.sub.3, 66.sub.3 is in a vertical position that is
generally below the carried wheels 62.sub.1, 66.sub.1; and the
carried wheels 62.sub.3, 66.sub.3 are located longitudinally in
front of the carried wheels 62.sub.2, 66.sub.2.
[0115] When the longitudinal end segment 50' of the endless track
41' contacts the rock 73 at a contact point, the wheel devices
54'.sub.1, 54'.sub.2 react to this contact. In this example, the
general slope of the rock 73 has a relatively steep angle. The
general slope of the rock 73 determines where the contact point
between the rock 73 and the track 41' may occur, which determines
the manner in which the wheel devices 54'.sub.1, 54'.sub.2 react to
the rock 73. In this case, the steep angle of the general slope
causes the track 41' to contact the rock 73 at a location on the
track 41' that is generally longitudinally aligned with a
mid-portion of each of the carried wheels 62.sub.3, 66.sub.3 (i.e.,
a portion vertically aligned with its respective axis of rotation).
The position of this contact point causes the carried wheels
62.sub.3, 66.sub.3 to momentarily stop moving. Because of the
forward momentum of the track assembly 16'.sub.i, the carried
wheels 62.sub.3, 66.sub.3 act as a temporary pivot and, as they are
mounted to the wheel carriers 60, 64, they cause the wheel carriers
60, 64 to turn about the axis 61, 67 in a counterclockwise
direction.
[0116] This turning motion of the wheel carriers 60, 64 in a
counterclockwise direction adjusts the angular position of each of
the carried wheels 62.sub.1, 66.sub.1, 62.sub.2, 66.sub.2.
Specifically, in this case, this turning motion causes each of the
carried wheels 62.sub.1, 66.sub.1 to follow an arc to a new angular
position where it also engages the rock 73 via the track 41, while
it causes each of the carried wheels 62.sub.2, 66.sub.2 to move
upwardly.
[0117] The wheel carriers 60, 64 and the carried wheels
62.sub.1-62.sub.3, 66.sub.1-66.sub.3 turning about the axis 61, 67
induces a change in curvature of the longitudinal end segment 50'
of the endless track 41'. In particular, the change in curvature of
the longitudinal end segment 50' of the endless track 41' allows
that segment of the track 41' to generally conform to the general
slope of the rock 73 and can facilitate its surmounting. Indeed, in
this example, the change in curvature is such that the portion of
the track 41' between the carried wheels 62.sub.3, 66.sub.3 and the
carried wheels 62.sub.1, 66.sub.1 is oriented generally upwardly at
an angle corresponding generally to the general slope of the rock
73. In this case, this results in the carried wheels 62.sub.1,
66.sub.1 and 62.sub.3, 66.sub.3 becoming vertically in-line with
each other, since the rock 73 presents a near-vertical face to the
track assembly 16'.sub.i.
[0118] In this example, upon reaching a top part of the rock 73, a
second counterclockwise rotation of the wheel carriers 60, 64 is
initiated. More particularly, up to the point where wheel devices
54'.sub.1, 54'.sub.2 reach the top part of the rock 73, the carried
wheels 62.sub.1, 66.sub.1 and the carried wheels 62.sub.3, 66.sub.3
remain generally vertically in-line with each other. In this
configuration, the carried wheels 62.sub.1, 66.sub.1 first reach
the top part of the rock 73, which is considerably less steep than
the general slope of the rock 73 initially encountered. This change
in slope results in the contact point between each of the carried
wheels 62.sub.1, 66.sub.1 and the top part of the rock 73 shifting
back towards the lower part of that wheel. Thus, with the forward
momentum of the track assembly 16'.sub.i, when the carried wheels
62.sub.1, 66.sub.1 reach the top part of the rock 73, they cause
the wheel carriers 60, 64 to turn about the axis 61, 67 a second
time in a counterclockwise direction.
[0119] As it goes down the rock 73, the wheel devices 54'.sub.1,
54'.sub.2 operate in a manner reverse to that previously described.
In particular, the carried wheels 62.sub.1, 66.sub.1 and the
carried wheels 62.sub.3, 66.sub.3 follow a general downward slope
of the rock 73 to return to the first ground level.
[0120] While in this embodiment the wheel devices 54'.sub.1,
54'.sub.2 of each of the track assemblies 16'.sub.1, 16'.sub.2 are
configured in a particular way, they may be configured in various
other ways in other embodiments.
[0121] For example, in some embodiments, two or more than three
carried wheels (similar to the carried wheels 62.sub.1-62.sub.3,
66.sub.1-66.sub.3) may be rotatably mounted to each of the wheel
carriers 60, 64 of the track assembly 16'.sub.i. For instance, in
some embodiments, fourcarried wheels may be rotatably mounted to
any one of the wheel carriers 60, 64. These four carried wheels may
be arranged in a rectangular configuration, i.e., their respective
axes of rotation may define a rectangle (e.g., a square) in which
is located the axis 61, 67 of the wheel carrier 60, 64 to which
they are rotatably mounted.
[0122] As another example, instead of being all mounted on one
lateral side of each of the wheel carriers 60, 64, in some
embodiments, carried wheels such as the carried wheels
62.sub.1-62.sub.3, 66.sub.1-66.sub.3 may be mounted on both lateral
sides of any one of the wheel carriers 60, 64. For instance, in
some embodiments, two of the carried wheels 66.sub.1-66.sub.3 may
be mounted on the inner lateral side of the wheel carrier 64 that
lies proximate to a main body of the ATV 10, while the remaining
one of the carried wheels 66.sub.1-66.sub.3 may be mounted on the
opposite, outer lateral side of the wheel carrier 64.
[0123] As yet another example, in some embodiments, the track
assembly 16.sub.i may comprise more or less than two wheel devices
such as the wheel devices 54'.sub.1, 54'.sub.2. For instance, in
some embodiments, the track assembly 16.sub.i may comprise three or
four wheel devices such as the wheel devices 54'.sub.1, 54'.sub.2
that are laterally spaced from one another and each carry three or
more carried wheels such as the carried wheels 62.sub.1-62.sub.3,
66.sub.1-66.sub.3.
[0124] As yet another example, instead of being positioned in the
front longitudinal end region 37' of the track assembly 16'.sub.i
in front of the support wheels 50'.sub.1-50'.sub.10, in some
embodiments, the wheel devices 54'.sub.1, 54'.sub.2 may be
positioned in the rear longitudinal end region 39' of the track
assembly 16', behind the support wheels 50'.sub.1-50'.sub.10 to
replace the rear idler wheels 48.sub.1, 48.sub.2. Alternatively, in
other embodiments, the track assembly 16'.sub.i may comprise wheel
devices such as the wheel devices 54'.sub.1, 54'.sub.2 both in the
front longitudinal end region 37' of the track assembly 16'.sub.i
and in the rear longitudinal end region 39' of the track assembly
16'.sub.i.
[0125] Although in this embodiment each of the track assemblies
16'.sub.1, 16'.sub.2 comprises the wheel devices 54'.sub.1,
54'.sub.2 but each of the track assemblies 14'.sub.1, 14'.sub.2
does not comprise such wheel devices, in other embodiments, each of
the track assemblies 14'.sub.1, 14'.sub.2 may comprise wheel
devices such as the wheel devices 54'.sub.1, 54'.sub.2 instead of
its front idler wheels 26.sub.1, 26.sub.2 and/or its rear idler
wheels 28.sub.1, 28.sub.2.
[0126] While in this embodiment the wheel devices
53.sub.1-53.sub.4, 54.sub.1-54.sub.4, 54'.sub.1, 54'.sub.2 are used
as part of track assemblies of an ATV, in other embodiments,
similar wheel devices constructed according to principles discussed
herein may be used as part of track assemblies of other types of
tracked vehicles. For example, in some embodiments, a wheel device
constructed according to principles discussed herein may be used as
part of a track assembly of a snowmobile. As another example, in
some embodiments, a wheel device constructed according to
principles discussed herein may be used as part of a track assembly
of a work vehicle, such as a construction vehicle (e.g., a
bulldozes, a backhoe loader, an excavator, etc.), an agricultural
vehicle (e.g., a harvester, a combine, a tractor, etc.) a forestry
vehicle (e.g., a feller-buncher, a tree chipper, a knuckleboom
loader, etc.) or any other vehicle operable off-road.
[0127] Although various embodiments and examples have been
presented, this was for the purpose of describing, but not
limiting, the invention. Various modifications and enhancements
will become apparent to those of ordinary skill in the art and are
within the scope of the invention, which is defined by the appended
claims.
* * * * *