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TITLE OF THE INVENTION
Track assembly for an all-terrain vehicle
FIELD OF THE INVENTION[0001] The present invention relates to all-terrain vehicles. More
specifically, the present invention is concerned with track assemblies for an
all-
terrain vehicle.
BACKGROUND OF THE INVENTION
(0002] Traditionally, two types of all-terrain vehicles are proposed
either the wheel type or the tracked type.
[0003) Generally, a wheeled vehicle is more maneuverable than a
tracked vehicle, but is not as efficient on uneven or soft terrain such as,
for
example snow.
[0004] Tracked all-terrain vehicles have been proposed, which
require complicated track assemblies comprising a track frame to maintain the
tension of the endless track belt and prevent it from loosening. Furthermore,
such vehicles have generally a large contact area with the ground, which
results in a decreased maneuverability and an increased impact on the often
soft terrain.
[0005] Therefore, there is still room for improvements toward an all-
terrain vehicle provided with track assemblies, which is maneuverable and
effective upon a variety of unstable or uneven surfaces, while designed to
maintain tension upon the endless track belts to keep them in their due course
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and prevent accidental loosening, and at the same time reducing the damages
inflicted on the terrain.
OBJECTS OF THE INVENTION
[0006] An object of the present invention is therefore to provide
improved track assemblies for an all-terrain vehicle.
SUMMARY OF THE INVENTION
(0007] More specifically, in accordance with the present invention,
there is provided an all-terrain vehicle comprising at least two track
assemblies
to support the all-terrain vehicle onto a ground surface, each one of said at
least two track assemblies comprising:
a longitudinal endless track belt provided with an inner
surface provided with a plurality of inner lugs and an outer surface provided
with a plurality of external lugs;
a mounting structure to mount said longitudinal endless track
belt to said vehicle,
wherein, when mounted to said mounting structure, said
longitudinal endless track belt has a punctually localized surface contact
with
the ground surface.
[0008] In accordance with another aspect of the present invention,
there is provided an endless track belt assembly comprising:
a track driving wheel provided with a plurality of teeth;
an endless track belt provided with an inner surface having a
plurality of inner lugs and an outer surface having a plurality of external
lugs,
said endless track belt being wounded around said track driving wheel;
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wherein a) said teeth are so spaced that a distance between
two consecutive teeth spans a distance separating two consecutive inner lugs
of said endless track belt and b) said endless track belt, when mounted to
said
track riving wheel, has a punctually localized contact with a ground surface.
[0009] In accordance with another aspect of the present invention,
there is provided a method for mounting an endless track belt on a all-terrain
vehicle, comprising the acts of:
providing an endless track belt having inner lugs and external
lugs;
providing a track driving wheel having a plurality of teeth so
spaced that a distance between two consecutive of the plurality of teeth spans
a distance separating two consecutive of a plurality of inner lugs of the
endless
track belt;
interconnecting the track driving wheel to an inside idler
wheel and to an outside idler wheel; and
tensioning the endless track belt around the track driving
wheel, the inside idler wheel and the outside idler wheel so that the endless
track belt has a punctually localized surface contact with a ground surface.
(0010] Other objects, advantages and features of the present
invention will become more apparent upon reading of the following non-
restrictive description of preferred embodiments thereof, given by way of
example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the appended drawings:
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[0012] Figure 1 is a side elevational view of an all-terrain vehicle
provided with track assemblies according to an embodiment of the present
invention;
[0013] Figure 2 is a side elevational view of the front track assembly
of the vehicle of Figure 1, seen from of the outside of the all-terrain
vehicle;
[0014] Figure 3 is a side elevational view of the front track assembly
of the vehicle of Figure 1, seen form the inside of the all-terrain vehicle;
[0015] Figure 4 is a sectional view taken along the line 4-4 of Figure
3;
[0016] Figure 5 is an enlarged side view of an outside idler wheel
attachment of the track assembly of Figure 2;
[0017] Figure 6 is a sectional view of a rigid member of the track
assembly of Figure 2;
[0018] Figure 7 is a top plan view of the attachment of the front track
assembly of Figure 1 to the all-terrain vehicle;
[0019] Figure 8 is a side elevational view of a rear track assembly of
Figure 1, seen from the inside of the all-terrain vehicle;
[0020] Figure 9 is a top plan view of the attachment of the rear track
assembly of Figure 1 to the all-terrain vehicle;
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(0021) Figure 10 is a sectional view similar to Figure 4 but illustrating
a second type of endless track; and
[0022) Figure 11 is a sectional view similar to Figure 4 but illusfirating
a third type of endless track.
DESGRIPTION OF THE EMBODIMENT
[0023) A track assembly for an all-terrain vehicle according to an
embodiment of the present invention will now be described in details with
reference to the appended drawings.
(0024) Figure 1 shows an all-terrain vehicle 10 comprising a body 12
and four track assemblies (only two shown) according to the present invention
arranged in a plane adjacent to each side of the vehicle 10.
[0025) There are two identical track assemblies in the front of the all-
terrain vehicle 10, of which only one track assembly 14 is visible in Figure
1, in
place of conventional front wheels. Similarly, there are two identical track
assemblies, of which only one track assembly 16 is visible in Figure 1, in
place
of the conventional rear wheels.
[0026) Only the track assemblies 14 and 16 visible in Figure 1 will be
described hereinbelow. Furthermore, as they are symmetrical about a vertical
axis 22 when viewed from the outside of the vehicle 10 (see Figure 1 ), only
the
track assemblies 14 will be described hereinbelow. It is also to be noted that
the elements as seen from the outside of the vehicle 10 will bear the same
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numbers in the rear track assembly 16 than the corresponding ones in the front
track assembly 14, with a prime.
[0027] However, since the attachment of rear and front track
assemblies differs as seen from the inside of the vehicles 10, they will be
described separately.
[0028] The front track assembly 14 is better seen in Figure 2. It
comprises a longitudinal endless track belt 23 and a mounting structure to
mount the endless track belt 23 to the vehicle 10. The mounting structure
includes a track driving wheel 24, a pair of inside idler wheels 26, a pair of
outside idler wheels 28 and supports to interconnect the wheels 24, 26 and 28
as will be described hereinbelow.
(0029] The endless track belt 23 is provided with inner lugs 30 on its
inner surface 31 and with external lugs 32 on its outer surface 33. It is
wounded
around the track driving wheel 24 and the idler wheels 28 and 26.
[0030] As can be better seen from Figure 4, the track driving wheel
24 is mounted to a conventional hub 35 of the all-terrain vehicle 10. The
wheel
24 includes a first mounting plate 37 mounted to the hub 35 and a second
mounting plate 34 mounted to the first plate 37 via four bolt and spacer
assemblies 36. A circular disk 38 is mounted to the bolt and spacer assemblies
36 and includes equidistant wide teeth 40 contacting the inner surface 31 of
the
track 23.
(0031] As will be apparent to one skilled in the art, the equidistant
teeth 40 are so located as to cooperate with some of the inner lugs 30 of the
endless track belt 23. More precisely, as can be better seen from Figure 2,
the
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teeth 40 are spaced so that the distance between two consecutive teeth 40
spans the distance separating consecutive inner lugs 30 of the endless track
belt 23, in a meshing engagement, in such a way as to drive the endless track
belt 23.
(0032] Each of the inside idler wheels 26 includes a peripheral
portion in contact with the internal surface 31 of the track 23. The wheels 26
are interconnected by a spacing element (not shown).
[0033] Similarly, each outer idler wheel 28 includes a peripheral
portion in contact with the internal surface 31 of the track 23. The wheels 28
are interconnected by a spacing element 42.
[0034] The wheels 24, 26 and 28 are interconnected, as seen from
the outside of the track assembly 14, by an angled connecting element 44. The
angled connecting element 44 has a center portion 46 provided with an
aperture 48 in which bearings 50 are mounted. A fastener 52 connects the
connecting element 44 to the second plate 34 while allowing the angled
connecting element 44 to pivot about the fastener.
[0035] The connecting element 44 has a short arm 54 having a free
end to which the inside idler wheels 26 are rotatably mounted. The connecting
element 44 also has a long arm 56 having a free end to which the inside idler
wheels 28 are rotatably mounted as will be further discussed hereinbelow. The
connecting element 44 is better seen from the top plan view of Figure 6.
[0036] Turning now briefly to Figure 3 of the appended drawings, as
can be seen from the inside of the all-terrain vehicle 10, the idler wheels 26
and
28 of the front track assembly 14 are also directly connected together by an
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elbowed connection element 58. The inside idler wheels 26 are rotatably
mounted to a first end of the elbowed connection element 58 while the outside
idler wheels 28 are rotatably mounted to a second end of the elbowed
connection element 58.
[0037] The rotatable connection of the outside idler wheels 28 to the
angle connection element 44 and to the elbowed connection element 58 will
now be described with reference to Figure 5.
[0038] As will easily be understood by one skilled in the art upon
inspection of Figure 5, the tension of the endless track belt 23 is adjusted
by
the connection of the outside idler wheels 28 to the elements 44 and 58. For
concision purpose, only the connection of the wheels 28 to the elbowed
connection element 58 will be described.
[0039] With reference to the enlarged side view of Figure 5, a
tension adjusting assembly according to another aspect of the present
invention will be described. As can be seen from this figure, a distal end of
the
connection element 58 includes a slotted aperture 60 receiving a fastener 62
used to rotatably mount the wheels 28 to the assembly. By sliding the fastener
62 in the aperture 60, it is possible to increase or decrease the tension on
the
track 23. To adjust and maintain this track tension, a cam element 64, having
an outer periphery provided with notches 66 located at different distances
from
the attachment point of the element 64, is mounted to the fastener 62. By
selecting which notch 66 is in contact with a fixed pin 68 of the element 58,
a
predetermined tension may be maintained. It is to be noted that the cam
element 64 is provided with a handle 70 to facilitate the manipulation by a
user.
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[0040] Returning to Figure 4 of the appended drawings the endless
track 23 will be described in greater detail.
[0041] As can be seen from Figure 4, the overall profile of the track
23, from one side to the other, i.e. transversely, is generally convex.
However,
the convex profile of the track 23 is created by a lug arrangement comprising
two successive transverse rows of lugs arranged in a staggered relationship.
[0042] A first transverse row of lugs contains three lugs 72, 74 and
76 and a second row of lugs contains four lugs 78, 80, 82 and 84. These lugs
are symmetrical about a longitudinal axis (not shown).
[0043] A first lateral lug 72 of the first row includes three ground-
contacting surfaces separated by two indentations. The shape of lateral lug 72
is such that the ground contacting surfaces are generally transversally
convex.
[0044] A central lug 74 is centered about longitudinal axis and
includes two ground-contacting surfaces separated by an indentation. The
ground contacting surfaces are symmetrical about the longitudinal axis and are
generally transversally convex.
[0045] A second lateral lug 76 is a mirror image of lug 72 about the
longitudinal axis.
[0046] The first and second lateral lugs 72 and 76 are laterally
spaced apart from the central lug 74.
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[0047] In the second transverse row of lugs, a first intermediate lug
80 includes two ground-contacting surfaces separated by an indentation. The
ground engaging surfaces are slightly transversally convex.
[0048] A first external lug 78 includes two ground-contacting
surfaces that are separated by an indentation and are transversally convex.
[0049] Finally, the second intermediate lug 82 and the second
external lug 84 are respectively mirror images of lugs 80 and 78 with respect
to
the longitudinal axis. For concision purposes, these lugs will not be further
described herein.
[0050] Of course, the sequences described hereinabove of the lug
arrangement defined by the rows of lugs are repeated onto the entire external
surface of the endless track 23.
[0051] The endless track belt 23 further includes, for each row of
lugs, a stiffening rod 71, made of glass fibers for example. Each stiffening
rod
71 is embedded in the material forming the track belt 23 so as to be generally
parallel to the inner surface 31 thereof. The rods 71 provide enhanced
rigidity
to the endless track belt 23. The enhanced rigidity of the track belt 23 has
many
advantages. For example, it helps the track to provide adequate traction even
when the center portion of the track is not in direct contact with the ground,
as
illustrated in Figure 4. However, it has been found that this type of traction
may
be detrimental to the steering of the vehicle in some conditions.
[0052] As it is apparent from Figure 4 the ground contacting surtaces
of symmetrical lugs 78 and 84 are not aligned with the outer surfaces of the
other lugs to form a continuous profile. Indeed, the ground contacting
surfaces
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of lugs 78 and 84 are more angled and exceed the convex profile defined by
the other lugs. This configuration of the outer lugs is advantageous since it
further prevents the vehicle from tipping over during sharp turns at high
speed
when the vehicle 10 is severely tilted.
[0053] As mentioned hereinabove, the way the front track assembly
14 is attached to the body 12 of the vehicle 10 differs from the way the rear
track assembly 16 is attached to the body 12 of the vehicle 10. These two
attachments will be described hereinbelow.
[0054] The front track assembly 14 is attached to the body 12 of the
vehicle 10 in a fashion shown in Figures 4 and 7, while the rear track
assembly
16 is attached to the body 12 of the vehicle 10 in a fashion shown in Figure 8
and 9.
[0055] As seen in Figures 4 and 7, the front track assembly 14 is
mounted to a tubular wheel table 100 of the vehicle 10 by means of a generally
triangular plate 102 fastened thereto by a plurality of U-bolts 104, 106, 108
and
110. A rod 112 is connected between the elbowed connection element 58 and
a pivot 114 of the tubular wheel table 100. A first end of the rod 112 is
attached
to the elbowed connection element 58 by means of rubber damping elements
116, in such a way as to allow a vertical movement at this point of the rod
112
in relation to the elbowed connection element 58. A second end of the rod 112
is attached to the pivot 114 of the tubular wheel table 100 by means of an R-
clip 120, in such a way as to allow at this point a horizontal movement of the
plate 102 holding the tubular wheel table 100 relative to the elbowed
connection element 58.
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[0056] The front track assembly 14 is further attached to the body 12
of the vehicle 10 through a conventional rod 150 of the suspension system of
the vehicle 10 and a conventional rod 157 used for direction (see Figure 4).
[0057] As seen in Figures 8 and 9, the rear track assembly 16 is
mounted to the body 12 of the vehicle 10 by a rod 212. The rod 212 is
connected on a first end to the elbowed connection element 58′ by means of a
rubber damping attachment 216. It is attached, on a second end, to a tubular
chassis 130 of the body 12 of the vehicle 10 by means of a chipping joint 132
fastened thereto by an R-clip 134.
[0058] From the above description of the fashion in which the front
and rear track assemblies 14 and 16 are mounted to the body 12 of the vehicle
10, in relation to Figures 4 and 7, and 8 and 9 respectively, the present
invention provides for track assemblies that are easily removed or mounted to
the vehicle 10, through using R-clips (120 and 134), which enable
disconnecting the track assemblies from the vehicle in a simple manner.
[0059] As stated hereinabove, the interior surface 31 of the endless
track belt 23 is provided with a plurality of equally spaced lugs 30, which
ensure
a positive engagement with the teeth 40 provided on the outer circumference of
the wheel 24. In operation, the wheel 24 is coupled to a drive shaft, via the
hub
30, connected to an engine (not shown), in such a way that the engine drives
the wheel 24 in rotation. The wheel 24 thus drives the endless track belt 23
by
the meshing engagement of the teeth 40 with the internal lugs 30 of the
endless track belt 23.
[0060] It is further to be understood that the external lugs 32 on the
external circumference surface of the endless track belt 23 respectively exert
a
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positive mechanical connection with the underlying ground surface that
contributes to propel the vehicle 10.
[0061] Figure 10 and Figure 11 show sectional views similar to that
of Figure 4 but illustrating variants of an endless track that may be mounted
to
the track assembly of the present invention.
[0062] In Figure 10, the overall profile of the endless track belt 23a,
from one side to the other, i.e. transversely, is generally convex.
[0063] The convex profile of the endless track belt 23a is created by
the same lug arrangement as that described hereinabove in relation to Figure
4. In this specific embodiment however, the endless track belt 23a does not
include stiffening rods under each row of lugs. Consequently, the rigidity of
the
endless track belt 23a is less than the rigidity of the endless track belt 23
(Figure 4) and the profile of the endless track belt 23a conforms itself to
the
profile of the ground. Since the pressure is more localized in the center of
the
endless track belt 23a, a more punctually localized contact zone between the
endless track belt 23a and the ground 29 is created. In many cases, this
punctually localized contact zone makes the vehicle 10 more maneuverable.
[0064] Turning now to Figure 11, a third version of an endless track
belt 23b will be described. The endless track belt 23b is wounded around the
track driving wheel 24 and the idler wheels 28 and 26, is still provided with
inner lugs 30 on its inner surface 31. However, its outer surface is provided
with
rectangular lugs 86. Since there are no stiffening rods in the endless track
belt
23b, the endless track belt 23b is free to conform itself to the ground 29, as
seen in Figure 11. Furthermore, since the pressure is exerted only in the
middle
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of the endless track belt 23b by the wide teeth 40, a punctually localized
contact zone between the endless track belt 23b and the ground 29 is created.
[0065] As will be apparent to one skilled in the art, the endless track
belts 23a has a particularly punctually localized contact surface with the
ground
29. Indeed, since it is transversally convex, it generally contacts the ground
29
with a limited surface at any given time when the ground 29 is hard.
[0066] Furthermore, since there are no guiding rails for the endless
track belts 23, 23a or 23b, the external lugs only exert a pressure on the
ground 29, when it is hard, in the vicinity of the wide teeth 40 if the wheel
24.
These two combined features improve the maneuverability of the vehicle since
it emulates the contact of a conventional tire onto hard ground, given that a
shortened length of contact of the endless track with the ground surface
reduces the resistance to a turning force.
[0067] Of course, one skilled in the art could designed another
convex profile of the external lugs of the endless track belts 23 and/or
another
arrangement of the mounting assembly of the endless track belts 23 to the
vehicle 10 to obtain this « one point contact » feature without departing from
the
spirit and nature of the present invention. For example, one could provide a
guiding rail having a convex profile and transversally convex lugs to achieve
similar results.
[0068] As people in the art will understand, the all-terrain vehicle of
the present invention, provided with four endless track assemblies, can be
used
for a wide range of operations and terrain, while being highly mobile and
offering good running performance.
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[0069] The endless track structure maintains an adequate
configuration over a variety of surfaces.
[0070] It will be obvious to people skilled in the art that the present
invention can be applied both in the case of a two-wheel drive vehicle wherein
the power is typically applied only to the rear track belt assemblies and the
front
track assemblies merely facilitate steering, and in the case of a four-wheel
vehicle, wherein power is independently provided to each one of the four track
assemblies.
[0071] As will be further understood by one skilled in the art, the all-
terrain vehicle 10, equipped with track assemblies according to the present
invention, may be viewed as a snow vehicle since it may be used on snow as
efficiently as conventional snow vehicles such as snowmobiles, for example.
However, the one-point contact feature of the present invention allows the use
of the all-terrain vehicle on harder surface without the usual drawbacks of
tracked vehicles.
[0072] Interestingly, the present track assembly system can equip all
four wheels of an all-terrain vehicle or only the front or rear wheels
thereof,
since it only weakly reduces the speed of the vehicle relative to the
underground surface.
[0073] A further possibility would be to use track assemblies
according to the present invention in place of the rear wheels of a vehicle,
while
mounting skis in place of the front wheels thereof.
[0074] Although the present invention has been described
hereinabove by way of preferred embodiments thereof, it can be modified,
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without departing from the spirit and nature of the subject invention as
defined
in the appended claims.
English
