DRIVE TRACK FOR SNOWMOBILE OR TRACKED VEHICLE

CHENILLE D'ENTRAINEMENT POUR MOTONEIGE OU VEHICULE CHENILLE

English Abstract

A track formed of a molded rubber base sandwiching a cord layer, followed by a cross bar and a single layer of ply fabric extending longitudinally of the track.

French Abstract

Une chenille formée d'une base en caoutchouc moulé prend en sandwich une couche de câblé, suivie d'une traverse et d'une couche simple d'un pli s'étendant longitudinalement par rapport à la chenille.

Claims

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WHAT IS CLAIMED IS:
1. An endless snowmobile track for traction of a snowmobile, the endless
snowmobile track comprising:
a) a rubber-based body having: an inner side for facing a driving wheel of
the snowmobile; and a ground-engaging outer side for engaging a
ground surface on which the snowmobile travels; and
b) a plurality of cross bars embedded within the rubber-based body, spaced
apart from one another along a longitudinal direction of the endless
snowmobile track, and extending transversally to the longitudinal
direction of the endless snowmobile track; the endless snowmobile track
having a single ply of reinforcing woven fabric, the single ply of
reinforcing woven fabric being embedded within the rubber-based body.
2. An endless snowmobile track as claimed in claim 1, wherein the single ply
of
reinforcing woven fabric is closer to the ground-engaging outer side than to
the inner side in a thickness direction of the endless snowmobile track.
3. An endless snowmobile track as claimed in claim 1, wherein the single ply
of
reinforcing woven fabric is located within the rubber-based body such that a
neutral area separating a region of compressive stress of the endless
snowmobile track and a region of tensile stress of the endless snowmobile
track is closer to the ground-engaging outer side than to the inner side in a
thickness direction of the endless snowmobile track.
4. An endless snowmobile track as claimed in claim 1, wherein the single ply
of
reinforcing woven fabric comprises woven man-made fibers.
5. An endless snowmobile track as claimed in claim 1, comprising a layer of
cords embedded within the rubber-based body and extending generally

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parallel to one another and in the longitudinal direction of the endless
snowmobile track, each cord including a plurality of strands.
6. An endless snowmobile track as claimed in claim 5, wherein the strands of
each cord are twisted.
7. An endless snowmobile track as claimed in claim 5, wherein the strands of
each cord are made of at least one of Kevlar.TM., nylon and polyester.
8. An endless snowmobile track as claimed in claim 1, wherein the single ply
of
reinforcing woven fabric is located between the cross bars and the ground-
engaging outer side.
9. An endless snowmobile track as claimed in claim 8, comprising a layer of
cords embedded within the rubber-based body and extending generally
parallel to one another and in the longitudinal direction of the endless
snowmobile track, each cord including a plurality of strands, the layer of
cords being located between the cross bars and the inner side.
10. An endless snowmobile track as claimed in claim 1, wherein each cross bar
comprises composite material.
11. A snowmobile comprising an endless snowmobile track as claimed in claim
1.
12. An endless all-terrain vehicle (ATV) track for traction of an ATV, the
endless
ATV track comprising:
a) a rubber-based body having: an inner side for facing a driving wheel of
the AW; and a ground-engaging outer side for engaging a ground
surface on which the ATV travels; and

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b) a plurality of traction projections on the ground-engaging outer side, the
traction projections engaging the ground surface when the ATV travels
on the ground surface; the endless ATV track having a single ply of
reinforcing woven fabric, the single ply of reinforcing woven fabric being
embedded within the rubber-based body.
13. An endless ATV track as claimed in claim 12, wherein the single ply of
reinforcing woven fabric is closer to the ground-engaging outer side than to
the inner side in a thickness direction of the endless ATV track.
14. An endless ATV track as claimed in claim 12, wherein the single ply of
reinforcing woven fabric is located within the rubber-based body such that a
neutral area separating a region of compressive stress of the endless ATV
track and a region of tensile stress of the endless ATV track is closer to the

ground-engaging outer side than to the inner side in a thickness direction of
the endless ATV track.
15. An endless ATV track as claimed in claim 12, wherein the single ply of
reinforcing woven fabric comprises woven man-made fibers.
16. An endless ATV track as claimed in claim 12, comprising a layer of cords
embedded within the rubber-based body and extending generally parallel to
one another and in a longitudinal direction of the endless ATV track, each
cord including a plurality of strands.
17. An endless ATV track as claimed in claim 16, wherein the strands of each
cord are twisted.
18. An endless ATV track as claimed in claim 16, wherein the strands of each
cord are made of at least one of Kevlar.TM., nylon and polyester.

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19. An endless ATV track as claimed in claim 12, comprising a plurality of
cross
bars embedded within the rubber-based body, spaced apart from one
another along a longitudinal direction of the endless ATV track, and
extending transversally to the longitudinal direction of the endless ATV
track.
20. An endless ATV track as claimed in claim 19, wherein the single ply of
reinforcing woven fabric is located between the cross bars and the ground-
engaging outer side.
21. An endless ATV track as claimed in claim 20, comprising a layer of cords
embedded within the rubber-based body and extending generally parallel to
one another and in the longitudinal direction of the endless ATV track, each
cord including a plurality of strands, the layer of cords being located
between
the cross bars and the inner side.
22. An endless ATV track as claimed in claim 19, wherein each cross bar
comprises composite material.
23. An ATV comprising an endless ATV track as claimed in claim 12.
24. An endless snowmobile track as claimed in claim 4, wherein the woven man-
made fibers are woven nylon fibers.
25. An endless snowmobile track as claimed in claim 1, comprising a layer of
cords embedded within the rubber-based body and extending generally
parallel to one another and in the longitudinal direction of the endless
snowmobile track, the single ply of reinforcing woven fabric being spaced
apart from the layer of cords in a thickness direction of the endless
snowmobile track.

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26. An endless snowmobile track as claimed in claim 1, wherein, when operated
at a given speed, the endless snowmobile track consumes less power than if
the endless snowmobile track had two plies of reinforcing woven fabric.
27. An endless ATV track as claimed in claim 15, wherein the woven man-made
fibers are woven nylon fibers.
28. An endless ATV track as claimed in claim 12, comprising a layer of cords
embedded within the rubber-based body and extending generally parallel to
one another and in a longitudinal direction of the endless ATV track, the
single ply of reinforcing woven fabric being spaced apart from the layer of
cords in a thickness direction of the endless ATV track.
29. An endless AW track as claimed in claim 12, wherein, when operated at a
given speed, the endless ATV track consumes less power than if the endless
ATV track had two plies of reinforcing woven fabric.
30. An endless snowmobile track as claimed in claim 26, wherein the given
speed is above 100 miles per hour.
31. An endless ATV track as claimed in claim 29, wherein the given speed is
above 100 miles per hour.
32. An endless ATV track as claimed in claim 12, wherein individual ones of
the
traction projections are spaced apart from one another along a longitudinal
direction of the endless ATV track.
33. An endless ATV track as claimed in claim 32, wherein individual ones of
the
traction projections are spaced apart from one another along a widthwise
direction of the endless ATV track.

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34. An endless ATV track as claimed in claim 12, wherein a given one of the
traction projections comprises a first part having a first height and a second

part having a second height different from the first height, each of the first

height and the second height being measured along a thickness direction of
the endless ATV track.
35. An endless ATV track as claimed in claim 12, wherein a given one of the
traction projections comprises a first part having a first thickness and a
second part having a second thickness different from the first thickness, each

of the first thickness and the second thickness being measured along the
longitudinal direction of the endless ATV track.
36. An endless snowmobile track for traction of a snowmobile, the endless
snowmobile track comprising:
a) a rubber-based body having: an inner side for facing a driving wheel of
the snowmobile; and a ground-engaging outer side for engaging a
ground surface on which the snowmobile travels; and
b) a plurality of traction projections on the ground-engaging outer side, the
traction projections engaging the ground surface when the snowmobile
travels on the ground surface; the endless snowmobile track having a
single ply of reinforcing woven fabric, the single ply of reinforcing woven
fabric being embedded within the rubber-based body.
37. An endless snowmobile track as claimed in claim 36, wherein the single ply

of reinforcing woven fabric is closer to the ground-engaging outer side than
to the inner side in a thickness direction of the endless snowmobile track.
38. An endless snowmobile track as claimed in claim 36, wherein the single ply

of reinforcing woven fabric is located within the rubber-based body such that
a neutral area separating a region of compressive stress of the endless
snowmobile track and a region of tensile stress of the endless snowmobile

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track is closer to the ground-engaging outer side than to the inner side in a
thickness direction of the endless snowmobile track.
39. An endless snowmobile track as claimed in claim 36, wherein the single ply

of reinforcing woven fabric comprises woven man-made fibers.
40. An endless snowmobile track as claimed in claim 39, wherein the woven
man-made fibers are woven nylon fibers.
41. An endless snowmobile track as claimed in claim 36, comprising a layer of
cords embedded within the rubber-based body and extending generally
parallel to one another and in a longitudinal direction of the endless
snowmobile track, each cord including a plurality of strands.
42. An endless snowmobile track as claimed in claim 41, wherein the strands of

each cord are twisted.
43. An endless snowmobile track as claimed in claim 41, wherein the strands of

each cord are made of at least one of Kevlar .TM., nylon and polyester.
44. An endless snowmobile track as claimed in claim 36, comprising a plurality
of
cross bars embedded within the rubber-based body, spaced apart from one
another along a longitudinal direction of the endless snowmobile track, and
extending transversally to the longitudinal direction of the endless
snowmobile track.
45. An endless snowmobile track as claimed in claim 44, wherein the single ply

of reinforcing woven fabric is located between the cross bars and the ground-
engaging outer side.

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46. An endless snowmobile track as claimed in claim 44, comprising a layer of
cords embedded within the rubber-based body and extending generally
parallel to one another and in the longitudinal direction of the endless
snowmobile track, each cord including a plurality of strands, the layer of
cords being located between the cross bars and the inner side.
47. An endless snowmobile track as claimed in claim 44, wherein each cross bar

comprises composite material.
48. An endless snowmobile track as claimed in claim 36, comprising a layer of
cords embedded within the rubber-based body and extending generally
parallel to one another and in a longitudinal direction of the endless
snowmobile track, the single ply of reinforcing woven fabric being spaced
apart from the layer of cords in a thickness direction of the endless
snowmobile track.
49. An endless snowmobile track as claimed in claim 36, wherein, when
operated at a given speed, the endless snowmobile track consumes less
power than if the endless snowmobile track had two plies of reinforcing
woven fabric.
50. An endless snowmobile track as claimed in claim 49, wherein the given
speed is above 100 miles per hour.
51. An endless snowmobile track as claimed in claim 36, wherein individual
ones
of the traction projections are spaced apart from one another along a
longitudinal direction of the endless snowmobile track.
52. An endless snowmobile track as claimed in claim 51, wherein individual
ones
of the traction projections are spaced apart from one another along a
widthwise direction of the endless snowmobile track.

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53. An endless snowmobile track as claimed in claim 36, wherein a given one of

the traction projections comprises a first part having a first height and a
second part having a second height different from the first height, each of
the
first height and the second height being measured along a thickness
direction of the endless snowmobile track.
54. An endless snowmobile track as claimed in claim 36, wherein a given one of

the traction projections comprises a first part having a first thickness and a

second part having a second thickness different from the first thickness, each

of the first thickness and the second thickness being measured along the
longitudinal direction of the endless snowmobile track.
55. A snowmobile comprising an endless snowmobile track as claimed in claim
36.

Description

srur,
CA 02546314 2006-05-11
1
TITLE OF THE INVENTION
[0001] Drive track for snowmobile or tracked vehicle
FIELD OF THE INVENTION
[0002] The present invention pertains to a drive track and, more
particularly, to a track for snowmobiles or other tracked vehicles, having an
improved construction to decrease horse power, increase top speed and
improve durability of the track when the latter is driven at high rotational
speeds.
BACKGROUND OF THE INVENTION
[0003] Endless drive tracks for propelling, for example, a
snowmobile over snow, ice or other similar ground structure, are known in the
art. The mounting of this track to a snowmobile and the mounting of such track

on an all-terrain vehicle are well known. The track has a ground engaging
outer side and an inner side that receives and supports, on the lower run
thereof, a suspension which may consist of a wheel assembly or a slide rail
assembly, both of which are also well known in the art.
[0004] Conventionally, the track rotates by means of a motor driven
sprocket unit at the forward end of the vehicle and idle drive wheels are
mounted at the aft end of the vehicle to support the rear end of the track.
Sprockets engage a series of lugs integrally formed with the inner surface of
the track.
[0005] With reference to Figure 1, the endless body is generally
formed of a molded rubber base having, embedded therein, a first layer of

CA 02546314 2013-05-03
2
reinforcing fabric 38 extending longitudinally of the track, a series of
laterally
spaced cord strands 40 which extend between the first layer of fabric and
beneath a rod 32, and a second ply 36 fabric disposed above the rod 32. Such
arrangement has been shown to allow good track performance and longevity. It
is generally believed that an increased amount of fabric contributes these
performances. In areas of the track where there is no rod 32, it is about at
mid-
thickness of the track where the fiber of the rubber is the strongest, this
line of
zero stress in cross section of the track separating the region of compressive

stress from that of tensile stress being known as the neutral fiber.
[0006] In spite of efforts in this field, there is still a need for a lighter,
cost
effective track.
SUMMARY OF THE INVENTION
[0007] More specifically, there is provided a track for a tracked vehicle,
comprising a molded rubber base sandwiching a cord layer, followed by a cross
bar and a single layer of ply fabric extending longitudinally of the track.
[0007A] As embodied and broadly described herein, the present invention
provides an endless snowmobile track for traction of a snowmobile. The endless

snowmobile track comprises a rubber-based body having an inner side for facing

a driving wheel of the snowmobile and a ground-engaging outer side for
engaging a ground surface on which the snowmobile travels. The endless
snowmobile track further comprises a plurality of cross bars embedded within
the
rubber-based body, spaced apart from one another along a longitudinal
direction
of the endless snowmobile track, and extending transversally to the
longitudinal
direction of the endless snowmobile track. The endless snowmobile track has a
single ply of reinforcing woven fabric that is embedded within the rubber-
based
body.

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2A
[0007B] As embodied and broadly described herein, the present invention
further
provides an endless all-terrain vehicle (ATV) track for traction of an ATV.
The
endless ATV track comprises a rubber-based body having an inner side for
facing a driving wheel of the ATV and a ground-engaging outer side for
engaging
a ground surface on which the ATV travels. The endless ATV track further
comprises a plurality of traction projections on the ground-engaging outer
side,
the traction projections engaging the ground surface when the ATV travels on
the
ground surface. The endless ATV track has a single ply of reinforcing woven
fabric that is embedded within the rubber-based body.
[0007C] As embodied and broadly described herein, the present invention
further
provides an endless snowmobile track for traction of a snowmobile. The endless

snowmobile track comprises a rubber-based body having an inner side for facing

a driving wheel of the snowmobile and a ground-engaging outer side for
engaging a ground surface on which the snowmobile travels. The endless
snowmobile track further comprises a plurality of traction projections on the
ground-engaging outer side, the traction projections engaging the ground
surface
when the snowmobile travels on the ground surface. The endless snowmobile
track has a single ply of reinforcing woven fabric that is embedded within the

rubber-based body.
[0007D] As embodied and broadly described herein, the present invention
further
provides an endless snowmobile track for traction of a snowmobile. The endless

snowmobile track comprises a rubber-based body having an inner side for facing

a driving wheel of the snowmobile and a ground-engaging outer side for
engaging a ground surface on which the snowmobile travels, a cord layer
embedded within the rubber-based body and including a plurality of cords
extending generally parallel to one another and in a longitudinal direction of
the
endless snowmobile track and a reinforcing woven fabric layer embedded within
the rubber-based body between the cord layer and one of the inner side and the

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2B
ground-engaging outer side. The endless snowmobile track is free of
reinforcing
woven fabric between the cord layer and the other one of the inner side and
the
ground-engaging outer side. The endless snowmobile track further comprises a
plurality of cross bars embedded within the rubber-based body, spaced apart
from one another along the longitudinal direction of the endless snowmobile
track, and extending transversally to the longitudinal direction of the
endless
snowmobile track.
[0007E] As embodied and broadly described herein, the present invention
further
provides an endless all-terrain vehicle (ATV) track for traction of an ATV.
The
endless ATV track comprises a rubber-based body having: an inner side for
facing a driving wheel of the ATV and a ground-engaging outer side for
engaging
a ground surface on which the ATV travels. The endless ATV track further
comprises a plurality of traction projections on the ground-engaging outer
side,
the traction projections engaging the ground surface when the ATV travels on
the
ground surface, a cord layer embedded within the rubber-based body and
including a plurality of cords extending generally parallel to one another and
in a
longitudinal direction of the endless ATV track and a reinforcing woven fabric

layer embedded within the rubber-based body between the cord layer and one of
the inner side and the ground-engaging outer side. The endless ATV track is
free
of reinforcing woven fabric between the cord layer and the other one of the
inner
side and the ground-engaging outer side.
(0007F] As embodied and broadly described herein, the present invention
further
provides an endless snowmobile track for traction of a snowmobile. The endless

snowmobile track comprises a rubber-based body having an inner side for facing

a driving wheel of the snowmobile and a ground-engaging outer side for
engaging a ground surface on which the snowmobile travels. The endless
snowmobile track further comprises a plurality of traction projections on the
ground-engaging outer side. The traction projections engage the ground surface

when the snowmobile travels on the ground surface. The endless snowmobile

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2C
track further comprises a cord layer embedded within the rubber-based body and

includes a plurality of cords extending generally parallel to one another and
in a
longitudinal direction of the endless snowmobile track. The endless snowmobile

track still further comprises a reinforcing woven fabric layer embedded within
the
rubber-based body between the cord layer and one of the inner side and the
ground-engaging outer side. The endless snowmobile track is free of
reinforcing
woven fabric between the cord layer and the other one of the inner side and
the
ground-engaging outer side.
[0007G] As embodied and broadly described herein, the present invention
further
provides an endless track for traction of a snowmobile or all-terrain vehicle
(ATV). The endless track comprises a rubber-based body having an inner side
for facing a drive wheel of the snowmobile or ATV and a ground-engaging outer
side for engaging the ground on which the snowmobile or ATV travels. The
endless track further comprises a plurality of rubber-based traction
projections
projecting outwardly from the ground-engaging outer side and a layer of
reinforcing fabric embedded within the rubber-based body. The endless track is

free of reinforcing fabric extending along the endless track between the inner

side and the layer of reinforcing fabric and free of reinforcing fabric
extending
along the endless track between the ground-engaging outer side and the layer
of
reinforcing fabric.
[0007H] As embodied and broadly described herein, the present invention
further
provides an endless track for traction of a snowmobile or all-terrain vehicle
(ATV).
The endless track comprises a rubber-based body having an inner side for
facing
a drive wheel of the snowmobile or ATV and a ground-engaging outer side for
engaging the ground on which the snowmobile or ATV travels. The endless track
further comprises a plurality of rubber-based traction projections projecting
outwardly from the ground-engaging outer side and a layer of reinforcing
fabric
embedded within the rubber-based body. The endless track does not comprise

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2D
two layers of reinforcing fabric embedded within the rubber-based body and
spaced apart from one another.
[00071] As embodied and broadly described herein, the present invention
provides an endless track for traction of a snowmobile or all-terrain vehicle
(ATV).
The endless track comprises a rubber-based body having an inner side for
facing
a drive wheel of the snowmobile or ATV and a ground-engaging outer side for
engaging the ground on which the snowmobile or ATV travels. The endless track
further comprises a plurality of rubber-based traction projections projecting
outwardly from the ground-engaging outer side and a layer of reinforcing
fabric
embedded within the rubber-based body. When operated at a given speed, the
endless track consumes less power than if the endless track had an additional
layer of reinforcing fabric embedded within the rubber-based body and spaced
apart from the layer of reinforcing fabric.
[0008] Other objects, advantages and features of the present invention will
become more apparent upon reading of the following non-restrictive description

of embodiments thereof, given by way of example only with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the appended drawings:

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[0010] Figure 1 is a cross section of a track as known in the art;
[0011] Figure 2 is a perspective view of a portion of a track
according to an embodiment of the present invention;
[0012] Figure 3 is a cross-sectional view of the of Figure 2;
[0013] Figure 4 is a graph of power as a function of speed, used by
a track according to the present invention, in a test without traction; and
[0014] Figure 5 is a graph of power as a function of speed, used by
a track according to the present invention, in a test including traction.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0015] As shown in Figure 2, a track 10 according to an embodiment
of the present invention comprises a ground engaging outer side 12 and an
inner side (not seen in Figure 2).
[0016] As seen in the cross-section of Figure 3, the track 10 is
formed of a molded rubber base 30 sandwiching a cord layer 32, followed by a
cross bar 34 and a single layer of ply fabric 36 extending longitudinally of
the
track.
[0017] The cross bar 34 may consists of a rod as known in the art,
made of composite material for example. It is located at spaced intervals
along
the longitudinal direction of the track beneath the profiles 14 projecting
from the
outer side 12 of the track.

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[0018] The cord layer 32 comprises a dense strand arrangement
formed of a twist arrangement of strands, comprising for example at least 18
strands per inch for a cord of 1.25 mm. The strands include high strength,
light
weight materials such as man made fibers, such as KevlarTM, nylon, and
polyester fabric for example
[0019] The cord layer 32 extends on the rubber base 30 and passes
beneath the rod 34.
[0020] The cord layer 32 may be discontinued at locations of the
track where the idler wheels pass.
[0021] The ply of fabric 36 includes woven man-made fibers such as
nylon for example.
[0022] As shown in Figures 4 and 5, the present track is found to
necessitate equal or less power, which goes against the current belief in the
industry that the greater the amount of fabric in the track composition, the
better the performances.
[0023] People in the art will appreciate that the present invention
provides, in contrast to a track standardly made in the art and including an
arrangement of rubber, a first ply fabric, cord, rod, second ply fabric and
rubber,
a track comprising a single layer of ply fabric, yielding a track of reduced
thickness, weight and cost, while maintaining target performances thereof in
terms of power and longevity. In particular, the present composition is shown
to
decrease horse power, increase top speed and improve durability of the track
when the latter is driven at high rotational speeds. It has also been found to

CA 02546314 2006-05-11
optimize the so-called neutral fiber bringing it closer to the outer side of
the
track.
[0024] The present track may be used for a range of tracked
vehicles.
[0025] Although the present invention has been described
hereinabove by way of embodiments thereof, it may be modified, without
departing from the nature and teachings of the subject invention as defined in

the appended claims.
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Representative Drawing