Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF THE INVENTION
Powder snow track for snowmobile
FIELD OF THE INVENTION
[0001] The present invention pertains to an endless track. More
specifically, the present invention is concerned with a track having an
enhanced traction performance over a range of surfaces.
BACKGROUND OF THE INVENTION
[0002] A propulsion system generally found on tracked vehicles
such as snowmobiles consists of a pair of longitudinally spaced apart wheel
structures arranged on opposite sides of the vehicle chassis, which is driven
by
a pair of endless, substantially inextensible belts, each having an inner
surface
and a ground-engaging surface.
[0003] The inner surface is provided with a series of longitudinally
spaced members, which guide the track relative to driving and tracking wheels
forming part of the wheel structures. The ground-engaging surface of the belt
is
formed of a plurality of longitudinally spaced tread members that provide
traction to the vehicle when traveling on various ground conditions. The
ground-engaging surface of the track may comprise a series of integral
profiles
having various configurations to provide traction to the snowmobile.
[0004] Therefore, a track is usually formed of a body of elastomeric
material, the ground-engaging surface thereof displaying a series of
transverse
profiles that provide traction for the snowmobile as it travels over a
surface,
2A
while the inner surface of the track displays a series of integral lugs, which
are
contacted by sprocket wheels that drive the snowmobile track in rotation.
[0005] In spite
of a number of developments in the field of tracks,
there is still a need in the art for a track allowing efficient traction of a
tracked
vehicle over a range of surface conditions.
SUMMARY OF THE INVENTION
[0006] There is
provided a track comprising an endless drive belt
with a ground-engaging surface bearing a series of transversally extending
treads, wherein each tread comprises a flexible top part operable to bend and
thereby cause a compacting action that compacts powder snow into packed
snow, and a rigid bottom part operable to cause grabbing action that provides
traction on the packed snow.
[0007] There is
also provided an endless belt for a snowmobile track
having a ground engaging surface bearing treads, each tread having a top part
and a bottom part, said top part being flexible and operable to bend and cause
a compacting action on the powder snow and transform it into packed snow,
and said bottom part being rigid and operable to create a grabbing action on
the packed snow.
[0007A] There is
also provided a track for traction of a vehicle. The track
is mountable around a plurality of wheels which comprises a drive wheel for
imparting motion to the track. The track comprises elastomeric material to
flex
around the wheels. The track comprises an inner surface for facing the wheels,
a ground-engaging outer surface for engaging the ground, and a plurality of
traction projections projecting from the ground-engaging outer surface and
distributed in a longitudinal direction of the track. Each traction projection
being
integrally formed with the ground-engaging outer surface and comprises a top
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2B
part and a bottom part. The top part OT me traction projection is more
flexible
than the bottom part of the traction projection to bend relative to the bottom
part of the traction projection and compact matter on the ground when the
traction projection engages the ground.
[0007B] There is
also provided a track for traction of a vehicle. The track
is mountable around a plurality of wheels which comprises a drive wheel for
imparting motion to the track. The track comprises elastomeric material to
flex
around the wheels. The track comprises an inner surface for facing the wheels,
a ground-engaging outer surface for engaging the ground, and a plurality of
traction projections projecting from the ground-engaging outer surface and
distributed in a longitudinal direction of the track. A given one of the inner
surface and the ground-engaging outer surface comprises a texture including a
plurality of longitudinal rigidifiers to increase a rigidity of the track in
the
longitudinal direction of the track.
[0007C] There is
also provided a track for traction of a vehicle. The track
is mountable around a plurality of wheels which comprises a drive wheel for
imparting motion to the track. The track comprises elastomeric material to
flex
around the wheels. The track comprises an inner surface for facing the wheels,
a ground-engaging outer surface for engaging the ground, and a plurality of
traction projections projecting from the ground-engaging outer surface and
distributed in a longitudinal direction of the track. The ground-engaging
outer
surface comprises a texture including a plurality of longitudinal rigidifiers
to
increase a rigidity of the track in the longitudinal direction of the track.
[0008] Other
objects, advantages and features of the present
invention will become more apparent upon reading of the following non-
restrictive description of specific embodiments thereof, given by way of
example only with reference to the accompanying drawings.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the appended drawings:
[0010] Figure 1 is a top partial perspective view of a track according
to an embodiment of the present invention;
[0011] Figure 2 is a top partial view of the track of Figure 1; and
[0012] Figure 3 is a cross section of a tread extending from a
ground-engaging surface of the track of Figures 1 and 2.
DESCRIPTION OF SPECIFIC EMBODIMENTS
[0013] Generally stated, the present invention provides a track that
allows an improved performance over a range of surfaces, including snow in a
variety of states, from powder snow to hard snow, or sand from wet to
hardened sand for example.
[0014] Turning to Figures 1 and 2 of the appended drawings, a track
to an embodiment of the present invention will now be described.
[0015] A track 10 typically comprises an endless drive belt 12 trained
around drive sprockets or wheels (not shown) for driving the belt 12 in an
endless path.
[0016] The belt 12 has an inner surface face (not seen) and a
ground-engaging surface 16, which, as it passes along a lower run of the belt
12, engages a surface (not shown) to be traversed. The inner track surface is
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typically provided with spaced drive lugs, which are spaced along the length
of
the inside of the belt 12 for engaging the drive wheels (not shown) as is well
known in the art.
[0017] The ground-engaging surface 16 comprises a series of
transversally extending treads 20 and 21 extending generally from a center of
the ground-engaging surface 16 to lateral edges thereof. The treads 20, 21
may be made of a rubber material.
[0018] The endless belt 12 may be made of flexible rubber or flexible
rubber reinforced by rods to strengthen the track, as is well known in the
art.
Typically, conventional tracks include, embedded in the rubber material of the
body of the belt 12 and in the region the treads 20, 21, such reinforcing
rods,
either metallic or plastic, to provide transverse rigidity to the track 10.
Moreover,
the track 12 may comprise longitudinal perforated bands 30 supporting steel
fasteners, as known in the art.
[0019] As illustrated in Figure 3, each tread 20, 21 has a straight
profile, devoid of lateral curvature, from a top part 22 thereof to a bottom
part
24 thereof, and an outer edge 32 of the top part 22 is generally flat.
Moreover,
the top part 22 has a section smaller than the bottom part thereof 24, the
bottom part 24 thus being more massive and rigid. The reduced section of the
top part 22 provides increased flexibility of this part of the tread 20, 21.
[0020] It is found that on powder snow for example, the top parts 22
are allowed to bend, thereby compacting the snow instead of cutting
therethrough, which results in an enhanced traction of the tracked vehicle
over
the powder snow. Indeed such a compacting effect assists the vehicle into
uplifting and extracting itself from heavy snow, instead of digging itself
deeper
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therein. On packed snow, enhanced traction is also achieved through a grabbing
action of the bottom parts 24.
[0021] Such a
non-uniformity between the top and bottom parts of the treads
therefore allows an enhanced traction over a range of snow conditions.
Moreover, it
is found that it contributes to extending the service life of the track.
[0022] It is
further found that treads 21 located at the position of the
reinforcing rods of the track during the molding stage of the track are
efficient in
allowing an easier fabrication process. In order not to increase the weight of
the
track, these treads 21 may be provided with a reduced height compared to
treads
20.
[0023] The
ground-engaging surface 16 may further comprise a longitudinal
texture 26 made of adjacent longitudinal ribs. For example, there may between
about 10 and 300 ribs of a height between about 10 and 250 milli-inches, over
a
width of the track of 15 inches. Such longitudinal texture is found to
increase rigidity
in flexion of the track 10.
[0024]
Obviously, such a track may be used for recreational vehicles,
snowmobiles or ATV for example.
[0025] Although
the present invention has been described hereinabove by
way of specific embodiments thereof, it can be modified, without departing
from the
nature of the subject invention as described herein.