Note: Descriptions are shown in the official language in which they were submitted.
CA 02574729 2007-01-23
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Title of the Invention
[0001 ] Traction Assembly for Vehicles and Components Therefor.
Cross-Reference to Related Applications
[0002] The present application claims the benefits of commonly assigned
Canadian
Patent Application No. 2,533,851, filed on January 24, 2005.
Field of the invention
[0003] This invention generally relates to traction assemblies for vehicles
and to certain
components therefor. Without being limitative in nature, the present invention
particularly relates to traction assemblies used a wheel replacements for
heavy vehicles
(i.e. vehicles weighing 5000 kg or more) such as, but not limited to, heavy
machineries,
agricultural equipments, construction equipments and forestry equipments.
Background of the Invention
[0004] The type of surfaces over which a vehicle is ridden significantly
affects its
capacity and efficiency.
[0005] While the riding behavior is one of the most important aspects involved
in the
conception of most vehicles, the ability to allow interchangeability of parts
or to retrofit
new components on existing vehicles generally greatly satisfies the owner of
vehicles and
represents an interesting market source for vendors of specialized parts
destined to
vehicles such as All-Terrain Vehicles (hereinafter "ATV"), light trucks,
jeeps, etc.
[0006] It is known in the art that vehicles with wheels are sometimes
inappropriate for
riding over certain types of terrain which are muddy, soft, sandy, snow-
covered or the
like. The wheels of such vehicles generally tend to sink into the ground when
used over
terrains as described above.
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[0007] In order to enhance the capabilities of wheel-equipped vehicles over
such terrains,
numerous types of wheel replacing traction assemblies have been proposed
throughout
the years. These assemblies generally involve the replacement of the wheels
connected to
the drive train of the vehicle with assemblies generally comprising a sprocket
wheel, a
support structure or frame, idler and/or road wheels and a traction band
mounted
therearound.
[0008] The traction band used in these assemblies generally has a larger
contact area with
the ground. Therefore, the weight of the vehicle is spread over a much larger
area,
thereby diminishing the pressure applied to the ground surface. When the
ground surface
is soft such a snow or mud, the vehicle equipped with these traction
assemblies will have
a lesser tendency to sink and the general traction of the vehicle will be
enhanced
accordingly.
[0009] Different types of traction assemblies have been proposed to replace
the wheels of
almost every kind of wheeled vehicles. Nowadays, traction assemblies exist to
replace the
wheels of ATVs, light trucks and jeeps, agricultural and farming equipments
and other
heavy machinery.
[0010] Still, the particular design of a traction assembly for use on small
vehicles such as
ATV or light truck can rarely be applied to a traction assembly for use on
farming
equipments and/or other similar heavy and/or large vehicles. The weight of the
vehicle
and the strain applied to the traction assembly when in use are substantially
different
according to the type of vehicle onto which the assembly is installed.
[0011] Different types of traction assemblies for heavy machineries exist in
the art. See
for example "Converter Assembly for Converting a Drive-Wheel Tractor into a
Track-
Driven Tractor" (U.S. Patent No. 5,240,084, granted to Peter J. Christianson),
"Tracklaying Vehicles" (U.S. Patent No. 5,273,126, granted to John N. Reed et
al.),
"Endless Belt Traction Device for Vehicles" (U.S. Patent No. 5,388,656,
granted to
Richard Lagasse), "Articulated Vehicle" (U.S. Patent No. 6,116,362, granted to
William
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Schubert et al.), "Working Vehicle with Semicrawlers" (U.S. Patent No.
6,199,646,
granted to Yushifumi Tani et al.) and "Triangular Crawler Apparatus" (U.S.
Patent No.
6,283,562, granted to Haruhiro Tsubota et al.).
[0012] One of the main problems with these traction assemblies is that the
support
structure that supports the idler wheels and/or the road wheels is made of a
single piece.
Since these assemblies are generally large pieces of equipment, the support
structure
comprises therein is generally also a large and generally long piece. Hence,
when the
traction assembly has to follow the curvature of the terrain, all the support
structure must
move, thereby implying large and often uncomfortable and unpleasant movements
for the
driver. Traction assemblies having suspension systems or lower pivotal point
exist but
they only partially prevent large movements of the support structure.
[0013] There is therefore a need for a traction assembly and certain
components therefor
which generally improve the riding condition of the vehicle and which also
preferably
obviate other shortcomings present in prior art traction assemblies.
Summary of the Invention
[0014] The present invention generally involves a traction assembly that can
preferably
replace a wheel on a vehicle. The present invention thus involves a vehicle
having a
frame and at least one traction axle. Preferably, the traction assembly of the
present
invention can replace wheels on either side of the front portion and/or the
rear portion of
the vehicle.
[0015] More particularly, the traction assembly of the present invention
generally
comprises a sprocket wheel adapted to be fixedly mounted to the axle of the
vehicle,
generally via the wheel hub, a support structure, also mounted to the vehicle,
which
generally supports idler wheels at each of its extremities and preferably a
plurality of road
wheels in-between, and a longitudinally extending traction band mounted around
the
sprocket wheel, the idler wheels and the road wheels and drivingly cooperating
therewith.
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[0016] According to one aspect of the present invention, the support structure
preferably
comprises two sub-structures or portions and at least two but preferably three
pivot
points. The support structure is generally adapted to be mounted to the frame
of the
vehicle, preferably near the traction axle where the sprocket wheel is
attached, via a first
pivot point and a second pivot point. These first and second pivot points are
generally
fixed. In other words, their distance with respect to the axis of the axle
never changes
when the vehicle is in use. The two sub-structures or portions are also
preferably
pivotally connected together via a third pivot point. The pivots are
preferably located at a
height lower than the height of the rotation axis of the sprocket wheel. In an
embodiment
of the present invention, the first pivot point is preferably generally
longitudinally
displaced in relation with the axis of the sprocket wheel and preferably
toward the front
on the vehicle whereas the second pivot point is preferably generally
longitudinally
displaced in relation with the axis of the sprocket wheel and preferably
toward the rear of
the vehicle. Also in this embodiment, the third pivot point is preferably
generally located
under the axis of the sprocket wheel. This particular arrangement generally
allows the
support structure to follow the curvature of the terrain independently of the
sprocket
wheel.
[0017] According to another aspect of the present invention, the support
structure
preferably supports, at each of its extremities, at least one but preferably a
plurality of
idler wheels which keep the traction band tensioned. The support structure
also supports a
plurality of road wheels to support the traction band and prevent it from
detracking. Since
the present traction assembly is preferably installed on farming tractors,
agricultural
vehicles, forestry equipments and other similar heavy machines, it may be
necessary to
install wide traction band on the assembly. Therefore, in order to provide
adequate
support for the traction band, it might be necessary for the traction assembly
to support a
plurality of idler and/or road wheels in a widthwise or parallel arrangement.
Accordingly,
the idler and/or road wheels are preferably mounted onto wheel axle assembly
wherein
the bearing assemblies are not in contact with the exterior environment.
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[0018] According to yet another aspect of the present invention, the structure
or one of
the sub-structures preferably comprises a tensioning system coupled to the
axle assembly
supporting the front or rear set of idler wheels. The tensioning system allows
longitudinal
displacements of the axle assembly which correspondingly increase or decrease
the
tension in the traction band.
[0019] According to another aspect of the invention, the idler and/or road
wheel axles are
preferably secured to the support structure with locking devices. The locking
devices
provide an easier way to mount and/or dismount the wheel axles independently
from each
other. Accordingly, an entire row of wheels can be easily removed for
repairing or
maintenance without dismounting the whole support structure.
[0020] In another aspect of the invention, the support structure is preferably
provided
with devices adapted reduce and preferably prevent the accumulation of debris
(e.g. soil,
dirt, gravel, snow, mud, rock) at the periphery of the idler and/or road
wheels while the
vehicle is moving. The devices, preferably fixedly mounted to the support
structure, are
also preferably provided with at least one and preferably a plurality of
members or
brackets extending therefrom between adjacent idler or road wheels in order to
reduce
and preferably prevent the accumulation of debris therebetween.
[0021] The features of the present invention which are believed to be novel
are set forth
with particularity in the appended claims.
Brief Description of the Figures
[0022] The above and other objects, features and advantages of the invention
will
become more readily apparent from the following description, reference being
made to
the accompanying drawings in which:
[0023] Figure 1 is a perspective view of the a first embodiment of the
traction assembly
of the present invention as installed on a vehicle.
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[0024] Figure 2 is a side view of the traction assembly of Fig. 1 as installed
on a vehicle.
[0025] Figure 3 is perspective view of the traction assembly of Fig. 1 as
installed on a
vehicle.
[0026] Figure 4 is side view of the sprocket wheel according to the present
invention.
[0027] Figure 5 is a perspective exterior view of the traction assembly of
Fig. 1 in the
closed position and without the band.
[0028] Figure 6 is a perspective exterior view of the traction assembly of
Fig. 1 in the
opened position and without the band.
[0029] Figure 7 is an exterior side view of the traction assembly of Fig. 1 in
the closed
position and without the band.
[0030] Figure 8 is an exterior side view of the traction assembly of Fig. 1 in
the opened
position and without the band.
[0031 ] Figure 9 is a perspective interior view of the traction assembly of
Fig. 1 in the
closed position and without the band.
[0032] Figure 10 is a perspective interior view of the traction assembly of
Fig. 1 in the
opened position and without the band.
[0033] Figure 11 is an interior side view of the traction assembly of Fig. 1
in the closed
position and without the band.
[0034] Figure 12 is an interior side view of the traction assembly of Fig. 1
in the opened
position and without the band.
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[0035] Figure 13 is an exterior perspective view of the traction assembly of
Fig. 1 in the
closed position and without the band.
[0036] Figure 14 is an exterior side view of the tensioning system according
to an
embodiment of the present invention.
[0037] Figure 15 is an interior side view of the tensioning system of Fig. 14.
[0038] Figure 16 is a bottom view of the a second embodiment of the traction
assembly
of the present invention.
[0039] Figure 17 is a top view of the traction assembly of Fig. 16, without
the sprocket
wheel.
[0040] Figure 18 is a cross-sectional side view of the traction assembly of
Fig. 16,
without the sprocket wheel.
[0041 ] Figure 19 is a cross-sectional perspective view of the traction
assembly of Fig. 16,
without the sprocket wheel.
[0042] Figure 20 is a fragmentary perspective view of the axle receiving
portion of the
support structure of the traction assembly of the present invention and of the
axle during a
first step of the installation.
[0043] Figure 21 is a fragmentary perspective view of the axle receiving
portion of the
support structure of the traction assembly of the present invention and of the
axle during a
second step of the installation.
[0044] Figure 22 is a fragmentary perspective view of the axle receiving
portion of the
support structure of the traction assembly of the present invention and of the
axle during a
third step of the installation.
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[0045] Figure 23 is a fragmentary perspective view of the axle receiving
portion of the
support structure of the traction assembly of the present invention and of the
axle during a
fourth step of the installation.
[0046] Figure 24 is a fragmentary perspective view of the axle receiving
portion of the
support structure of the traction assembly of the present invention and of the
axle during a
fifth step of the installation.
[0047] Figure 25 is a partial cross-sectional perspective view of the idler
wheels mounted
on an axle assembly.
[0048] Figure 26 is an exploded perspective view of the idler wheels and the
axle
assembly.
Detailed Description of the Preferred Embodiments
[0049] A novel traction assembly for vehicles and certain components therefor
will be
described hereinafter. Although the invention is described in terms of
specific illustrative
embodiments, it is to be understood that the embodiments described herein are
by way of
example only and that the scope of the invention is not intended to be limited
thereby.
[0050] As a preliminary note, as used hereinabove and hereinafter, the term
"elastomeric"
generally relates to any elastic and primarily non metallic materials such as
natural and/or
synthetic rubber, elastomers, polymers and/or combinations thereof used in the
manufacture of endless tracks.
[0051] Referring to Fig. 1, there is shown a first embodiment of the traction
assembly
100 as installed on the rear axle 11 of a farming tractor 10.
[0052] Fig. 2 presents in more details the main components of the traction
assembly 100.
The assembly 100 comprises a sprocket wheel 110 adapted to be mounted onto the
axle
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11 (or wheel hub) of a vehicle 10. In Fig. 2, the vehicle 10 is a farming
tractor. However,
the traction assembly 100 can replace the wheels of other heavy wheeled
vehicles without
departing from the scope of the invention. The sprocket wheel 110 comprises a
plurality
of generally evenly spaced sprocket teeth 112 located at the periphery
thereof. The
sprocket teeth 112 drivingly engages a traction band 120 which is also
tensioned around a
front and rear rows 151 of idlers wheels 150 and a plurality of road wheels
160. The idler
wheels 150 and the road wheels 160 are pivotally mounted onto a support
structure 130
via idler wheel axle 152 and road wheel axle 162 respectively. In a first
embodiment of
the present invention, the support structure 130 comprises a first pivot point
137 and a
second pivot point 147 (see Fig. 9) which pivotally connect the support
structure 130 to
the frame of the vehicle 10 via a bracket assembly 200 (see Figs. 5-6 and 9-
12). This first
pivot point 137 is preferably located under the axis of the axle 11 and
longitudinally
displaced with respect to the axis of the axle 11. Similarly, the second pivot
point 147 is
preferably located under the axis of the axle 11 and longitudinally displaced
with respect
to the axis of the axle 11. In the embodiment shown in Fig. 2, the first pivot
point 137 is
located on the front portion 133 of the support structure 130 and the second
pivot point
147 is located of the rear portion 135 of the support structure 130. In this
first
embodiment, the support structure 130 further comprises a third pivot point
131 which
pivotally links the generally front portion 133 and the generally rear portion
135 of the
structure 130. The rear portion 135 further comprises a tensioning system 170
described
in more details below.
[0053] The traction band 120, shown in Fig. 3, is preferably made of
elastomeric
materials. The traction band 120 is also preferably, but not exclusively, made
as a single
endless band. The traction band 120 generally comprises a ground-engaging
outer surface
121 and a sprocket engaging inner surface 123. The outer surface has a tread
pattern
which consists of a plurality of outwardly projecting traction lugs 122. The
particular
design and arrangement of the traction lugs 122 are chosen according to the
terrain over
which the vehicle is ridden. As for the inner surface 123, it generally
comprises a least
one and preferably a plurality of rows of longitudinally aligned sprocket-
engaging driving
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lugs 124. The driving lugs 124 are adapted to be drivingly engaged by the
teeth 112 of
the sprocket wheel 110.
[0054] As shown in more details in Fig. 4, it can be seen that the sprocket
wheel 110 is in
fact composed of three peripheral sprocket portions 111 and a central sprocket
portion
113. The reason for this multiple pieces sprocket 110 construction is the
weight. Should
the sprocket wheel 110 be made of a single piece of metal, the weight of the
wheel 110
would be excessive and the installation and uninstallation procedures would be
correspondingly harder.
[0055] The central or core portion 113 is generally adapted to be mounted on
the axle 11
(or wheel hub, not shown) of the vehicle 10. The central portion 113 is
mounted to the
axle 11 (or wheel hub) with mounting means known in the art (e.g. bolt and nut
assemblies).
[0056] The portions 111 are mounted at the periphery of the central portion
113 using nut
and bolt assemblies. Consecutive peripheral portions 111 are further secured
together via
attaching plate 115 and nuts and bolts assemblies.
[0057] The skilled addressee will understand that a traction assembly 100 for
use on a
smaller vehicle 10 could use a single piece sprocket wheel 110. In fact, the
present
invention contemplates the use of single piece and multiple pieces sprocket
wheel 110.
Therefore, the choice between a single piece sprocket wheel 110 and a multiple
pieces
sprocket wheel 110 depends upon the size of the traction assembly 100 and the
desired
ease of manipulation of the wheel 110.
[0058] Now referring to Figs. 5-13, the support structure 130 of a first
embodiment of the
present traction assembly 100 is shown in more details.
[0059] In Figs. 5, 7, 9 and 11, we can see the traction assembly 100 in its
normal closed
position. When the traction assembly 100 is in closed position, front portion
133 and rear
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portion 135 are in contact or in near contact around contact point 139. The
closed
position is the normal position when the traction assembly 100 is driven over
a generally
flat surface.
[0060] With prior art assemblies, when a traction assembly faces a bump or a
depression,
all the support structure has to move even though only the front of the
structure is in
contact with the bump (or depression). For small traction assembly, this
movement of the
support structure may be relatively small but for larger traction assembly,
the support
structure being a generally large member, the amplitude of the movement could
be quite
large. This, in turn, generally translates into abrupt movements which can be
uncomfortable for the driver.
[0061] Since the traction assembly 100 of the present invention in made of two
pivotally
connected portions 133 and 135, the movement of the support structure is
correspondingly less abrupt.
[0062] Now referring to Figs. 6, 8, 10 and 12, when the traction assembly 100
faces a
bump, the front portion 133 of the structure 130 will pivot around pivot point
137 in the
direction generally indicated by the arcuate arrow 237. In other words, the
forward
section 233 of the front portion 133 will raise whereas the rearward section
333 will
descend.
[0063] In its descending movement, the rearward section 333 will drag along
the pivot
point 131 which pivotally connects the front portion 133 to the rear portion
135. The
downward movement of the pivot point 131 is generally indicated by the arrow
231.
[0064] Since the front portion 133 and the rear portion 135 are pivotally
connected by the
pivot point 131, when the pivot point 131 descends with the rearward section
333, it
forces the forward section 235 of the rear portion 135 in a similar downward
motion. This
downward motion of the forward section 235 will induce, in reaction, a counter
pivotal
motion of the rear portion 135 around the second pivot point 147. The
direction of this
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pivotal motion is generally indicated by arrow 247. This pivotal motion 247
will then
induce an upward movement of the rearward section 335. The support structure
therefore
opens in the area 139 where the two portions 133 and 135 initially contacted
each other.
[0065] As clearly shown in Figs. 8 and 12, when the support structure is in
open position,
the skilled addressee will note that the support structure 130 defines a
generally curved
shape indicated by the curved arrow 230. This curved shape allows to better
follow the
curvature of the terrain without inducing abrupt movements in the traction
assembly and
ultimately, in the vehicle.
[0066] When the traction assembly returns on a generally flat surface, the
support
structure will generally return to its closed position.
[0067] The skilled addressee will understand that the traction assembly 100
could be
mounted in reverse wherein the pivot point 137 is located on the rear portion
135 and the
pivot point 147 is located on the front portion 133. The principles of the
operation would
stay the same albeit inverted.
[0068] As best seen in Fig. 13, the support structure 130 generally supports a
plurality of
road wheels 160 which are pivotally mounted thereto. In the preferred
embodiment of the
present invention, the road wheels 160 are mounted in multiple rows 161, each
row 161
comprising several road wheels 160 generally coaxially mounted onto an axle
assembly
260. This widthwise distribution of road wheels 160 in each row 161 generates
a better
and more uniform support for the traction band 120. However, the number of
rows 161
and the number of road wheels 160 in each row 161 are generally chosen
according to the
size of the traction assembly 100 and the size of the traction band 120 though
other
criteria could be also considered.
[0069] In a similar fashion, each of the forward section 233 of the front
portion 133 and
the rearward section 335 of the rear portion 135 supports a row 151 of idler
wheels 150.
As for the road wheels 160, the idler wheels 150 are generally coaxially
mounted on an
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axle assembly 250. This widthwise distribution of the idler wheels 150 in each
row 151
generates a better and more uniform support for the traction band and also
helps to
prevent detracking of the band 120.
[0070] The road wheels 160 and the idler wheels 150 located on a given axle
assembly
260 and 250 respectively are generally laterally and evenly spaced apart to
allow the
passage of the drive lugs 123 between two adjacent road or idler wheels 160 or
150. The
space between two adjacent wheels 150 or 160 is thus determined by the width
of the
drive lugs 123.
[0071] Now referring to Figs. 14 and 15, the rear portion 135 of the support
structure 130
further comprises a tensioning assembly 170. The tensioning assembly 170
comprises a
pair of plates 171, one located on each side of the support structure 130,
which are
slidingly mounted into grooves 172 on the rearward section 335 of the rear
portion 135
and held in place with nuts and bolts assemblies (not shown). Each plate 171
comprises a
generally U-shaped receiving area 173 adapted to receive the axle 152 of the
axle
assembly 250 of the idler wheels 150. The tensioning assembly 170 further
comprises a
pair of push-bolts 176 (shown in Fig. 2), one on each side of the support
structure,
threadedly mounted onto a threaded bracket 174 located on the rear portion 135
of the
support structure 130 and generally abutting on the plate 171. By screwing (or
unscrewing) the push-bolts, it is possible to push (or retract) the plates
171, effectively
pushing (or retracting) the idler wheels 150 and therefore tensioning (or
relaxing) the
traction band 120. Arrow 175 shows the general possible motions of the
tensioning
assembly when the push-bolt are actuated.
[0072] As the skilled addressee would understand, the tensioning assembly 170
could
alternatively be installed or provided on the forward portion 233 of the front
portion 133
of the support structure 130.
[0073] Referring now to Figs. 16 to 19, another embodiment of the present
invention is
shown. In this second embodiment, the support structure 130 is unitary though
the
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skilled addressee would understand that it could readily be provided with
pivotally
mounted front portion 133 and rear potion 135 as in Figs. 1 to 15. The present
invention
is therefore not so limited.
[0074] As mentioned above, the idler wheels 150 and the road wheels 160 are
laterally
spaced apart to allow the passage of the drive lugs 124 of the traction band
120.
However, by having idler wheels 150 and road wheels 160 so configured, debris
(e.g.
rock, gravel, sand, mud, snow, ice and the like) are likely to accumulate in
the space
defined between them and possibly, at the periphery of the idler wheels 150
and of the
road wheels 160.
[0075] In order to prevent or at least reduce such accumulation and as best
shown in Fig.
19, the second embodiment of the present invention is provided with devices
180 to
reduce and preferably prevent the accumulation of such debris at the periphery
of the
idler wheels 150 and of the road wheels 160 and also preferably between them.
[0076] As shown in Figs. 16 to 19, the devices 180 comprise one or more
laterally
extending members or beams 182, generally fixedly mounted to the structure
130, usually
but not exclusively by welding. The members 182 are generally provided in the
shape of
iron angle though other shapes could be used to obtain similar results. As
shown in the
figures, the members 182 are preferably positioned near or adjacent the outer
periphery of
the idler wheels 150 and the road wheels 160 in order to block or scrape
debris that might
be present thereon. Still, a gap is generally left between the members 182 and
the wheels
to prevent accidental contact between them.
[0077] In order to also reduce and prevent the accumulation of debris in the
space
between laterally adjacent wheels, the devices 180 are preferably further
provided with
brackets 183 which are themselves formed with outwardly extending fingers 184.
The
fingers 184 generally extend in the space between laterally adjacent wheels
and toward
the outer tube 154 or 164 of the axle assembly 250 or 260 in order to block or
scrape
debris that could be present on the axle assembly and/or in the space between
the wheels.
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Still, as for the members 182, as gap is left between the fingers 184 and the
axle
assemblies to prevent accidental contact.
[0078] In the embodiment of Figs. 16 to 19, one finger 184 preferably extends
between
each pair of adjacent wheels. Understandably and as shown in the figures, a
plurality of
fingers 184 can extend from a single bracket 183, the invention is not so
limited.
Moreover, though preferably mounted to the members 182, the brackets 183 could
alternatively be directly mounted to the structure 130 of the traction
assembly.
[0079] Now referring to Figs. 20 to 24, the different steps to mount and lock
the axle 152
(or 162) of the axle assembly 250 (or 260) into the axle receiving areas 270
of the support
structure 130 are shown. As shown in Fig. 20, the receiving area 270 generally
comprises a U-shaped axle receiving portion 271, opposite channel portions 272
and
opposite shoulder portions 273.
[0080] In the first step, shown in Fig. 20, the axle 152 of the axle assembly
250 is
generally inserted into the U-shaped portion 271 of the receiving area 270 of
the support
structure 130 via grooves 153 provided at the lateral extremities of the axle
152. The
grooves 153 of the axle 152 and the U-shaped portion 271 are preferably
complementary
in order to provide a secure arrangement therebetween and to prevent unwanted
movements.
[0081] In order to prevent the axle 152 from accidentally exiting the
receiving area 270
of the support structure 130, the axle 152 is preferably locked in place via
locking
element 190 and locking screw 195. The locking element 190 is generally
provided with
a threaded aperture 191 for receiving the locking screw 195.
[0082] As shown in Figs. 21 and 22, the locking element 190 is generally
inserted
laterally in the receiving area 270 via the slightly larger channel portions
272 provided
thereto. When the locking element 190 is fully inserted into the receiving
area 270, as
shown in Fig. 23, the locking screw 195 is threaded into the threaded aperture
191 until it
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abuts on the axle 152. Once the locking screw 195 abuts on the axle 152, the
locking
screw 195 is further screwed in order to move the locking element 190 toward
the
shoulder portions 273 of the receiving area 270. In order to provide a secure
arrangement
therebetween, the locking element 190 is preferably provided with grooves 192
complementary with the shoulder portions 273.
[0083] The complete installation is shown in Fig. 24 wherein the locking screw
195 abuts
on the axle 152 and wherein the locking element 190 abuts on the shoulder
portions 273.
[0084] To remove one row of wheels, either idler or road wheels, the steps of
the
foregoing process are effected in reverse.
[0085] As mentioned above, the wheels, either idler wheels 150 or road wheels
160, are
mounted onto respective axle assemblies 250 or 260. Since, for all intent and
purposes,
axle assemblies 250 and 260 are substantially identical in nature, only axle
assembly 250
shall therefore be further described. Still, it is to be understood that axle
assembly 260 is
of similar construction.
[0086] Referring first to the exploded view of Fig. 26, the axle assembly 250
generally
comprises an outer tube 154 into which is pivotally mounted the axle 152. The
pivotal
movement of the outer tube 154 with respect to the axle 152 is provided by two
bearing
and seals assemblies mounted at each extremity of the axle 152.
Understandably, the
bearing and seals assemblies are symmetrical in nature.
[0087] Starting with the component nearest the axle 152, the bearing and seals
assemblies
generally comprise a tapered roller bearing 251, a lock washer 252, a nut 253,
a radial
sea1254, an axial seal ring washer 255, an internal snap ring 256, an axial
sea1257 and an
external snap ring 258.
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CA 02574729 2007-01-23
File number : 11038-056
Revision : As Filed
Date : 2007/01/23
[0088] Once the axle 152 is mounted inside the outer tube 154 via the bearing
and seals
assemblies, the wheels 150 are press-fit on the outer tube 154 and secured in
place via
backing washer 156 and external snap ring 157 as shown in Figs. 25 and 26.
[0089] One of the particularity of the axle assembly 250 of the present
invention is that a
cylindrical chamber is defined between the axle 152 and the outer tube 154
once the
assembly 250 is fully assembled. This chamber is preferably filled with grease
via a
grease fitting 155 mounted at one extremity of the axle 152 and which is
fluidly
connected to the chamber via a duct 158 provided in the axle 152. By having an
internal
grease pressure higher than the ambient exterior pressure, the grease inside
the axle
assembly 250 will have a tendency to push outside any particles such as dust
and/or sand
that might enter the bearing and seals assemblies.
[0090] By preventing or at least reducing the entry of foreign particles in
the bearing and
seals assemblies of the axle assembly 250, the axle assembly 250 will be less
prone to
premature wear or even failure.
[0091] While illustrative and presently preferred embodiment(s) of the
invention have
been described in detail hereinabove, it is to be understood that the
inventive concepts
may be otherwise variously embodied and employed and that the appended claims
are
intended to be construed to include such variations except insofar as limited
by the prior
art.
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