Note: Descriptions are shown in the official language in which they were submitted.
CA 02417162 2003-O1-29
AD,1UST~BLC SNOWMOBILE SUSPENSION SYSTEM
FIELU OF THE~: INVENTION:
The present invention relates to the general field of snowmobile accessories
and is particularly concerned with an adjustable snowmobile suspension system.
I3ACKGRUlINU OF THE 1NVENTIUN:
Snownutbiles are used, extensively in some regions of the globe, either as a
means ot~ transportation, a recreational vehicle used during leisure time or
both.
W )ItVClltl()tlal snowmobiles include a bodv dctining a forward portion
curt;rininc tltc engine and drive mechanism. The body also defines a rearward
portion including a scat on which the driver and passengers arc sealed. 'flte
body is
tttuuntcd un a ~lrivin6 track for supporting and driving the vehicle on the
snow.
IIm tr;tck typically includes an endless belt mounted un at least a pair of
alis!nret ahrmkcts at its forward end. ~Chc sprockets arc suitably driven by
the engine.
I lae mullahs i,elt is ;rlsu tnountcd un a p;:ir of the line sprcreket carried
by an axle
a~lj;rccnt tire rear end uf~ the sttwvrnuhile.
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The front end of the vehicle employs a pair of laterally spaced skis carried
by
individual leaf type springs suspended from a corresponding steering rod. The
steering rods are linked to a central steering column operable by the driver
of the
snowmobile.
1'he skis are moveable to guide the vehicle and compensate for terrain
irregularities. The typical suspension system includes the leaf springs
disposed
between each of the skis and snowmobile to cushion the vehicle from bumps
encountered by the skis. Typically, a shock absorber is connected between an
intermediate point on the leaf springs and the top section of the ski in order
to
dampen vibrations in the leaf type springs.
The conventional snowmobile suspension systems, although somewhat
useful, suffer from a set of major drawbacks. One of the main drawback
associated
with prior art snowmobile suspension systems is that during cornering
conditions
when the snowmobile is steered so as to turn, the conventional semi-elliptic
leaf type
spring have a tendency to twist about the longitudinal axis of the ellipse.
The torsion
of the leaf type spring, in turn, causes the ski to sway, lift or heel. As a
result, the
contacting surface of the ski with the terrain is reduced, sometimes only to
the edge
of ski, leading to loss of adherence and potential loss of control o.f the
vehicle.
Another problem associated with conventional snowmobile suspension
systems is that the leaf type springs have a tendency to become less efficient
when
deflected pass a certain deflection value. Hence, conventional leaf type
springs,
used with conventional snowmobile suspension systems, become less efficient
under
impacts or great pressures. The impact varies the geometry of the steering
system so
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as to lessen its stability. Such lessening of stability is always undesirable.
Lack of
stability is more likely to be critical at times when springs are deflected,
for example,
as in a turn when a large part of the weight of the vehicle is transferred to
the
outboard ski. Yet another drawback, associated with conventional snowmobile
suspension systems, is the lack of adjustability of the stiffens of the
suspension
system. Indeed, prior art snowmobile suspension systems lack a means for
allowing
an intended user to easily and readily vary the stiffens of the suspension
system
depending on riding driving conditions, such as the weight being carried by
the
snowmobile and/or the type of terrain being traveled upon. Accordingly, there
exists
a need for an improved sIlOWnlObile SUSpellsloil SySte111.
Advantages of the present invention include that the proposed snowmobile
suspension system allows for cushioning of the vehicle from terrain
irregularities
while preserving stability of the vehicle even in cornering conditions. The
proposed
suspension system reduces heeling of the skis during cornering and, hence,
reduces
tl~e risks of leaping the adherence between the contacting surface of the ski
and the
riding surtacc.
Also, the proposed snowmobile suspension system reduces the risks of losing
efficiency of its dampening characteris~ics as the suspension system becomes
deflected by the weight of the vehicle or by having skis impact an obstacle.
Accordingly, stability of the vehicle and dampening characteristics of the
suspension
system are less likely to be affected at critical times such as in a turn when
some of
the weight is transferred on the outboard ski.
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rurthermore, the proposed snowmobile suspension system allows for quick,
easy and ergonomical adjustment of its dampening characteristics through a set
of
ergonomical steps without requiring special tooling or manual dexterity. Still
furthermore, the proposed snowmobile suspension system is designed so as to be
easily retro-fittable on conventional snowmobile vehicles with reduced risks
of
damaging the vehicle and/or the suspension system. Also, the device may be
retro-finable using conventional tools through a set of quick and ergonomical
procedures.
Still furthermore, the proposed snowmobile suspension system is designed so
as to be manufacturable using conventional forms of manufacturing so as to
produce
a suspension system that will be economically feasible, long lasting and
relatively
trouble free in operation.
I3RICF DCSCRIPTION OF TIIC DRAWINGS:
An embodiment of the present invention will now be disclosed, by way of
example, in reference to the following drawings, in which:
FIGURC 1: in a partial perspective view with sections taken out, illustrates a
snowmobile suspension system in accordance with an embodiment of the present
invention mounted behveen a conventional snowmobile ski and the front end of a
conventional snowmobile, the conventional snowmobile being only partially
shown;
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FIGURE 2: in a bottom perspective view, illustrates a snowmobile suspension
system in accordance with an embodiment of the present invention;
FIGURE 3: in a perspective view, illustrates the snowmobile suspension system
shown in CIG. ?:
FIGURE .t: in another perspective view, illustrates the snowmobile suspension
system shown in FIGS. 1 through 3;
FIGURE 5: in yet another perspective view, illustrates the snowmobile
suspension
system shown in hIGS. I through 4;
FIt:URE G: in a side elevational view, illustrates the snowmobile suspension
system shown in FIGS. 1 through 5.
UETAILEU UESCRI1'TIUN:
IZcierring to fIG. l, there i5 shown a snowmobile suspension system (1U) in
accordance whit an embodiment of the present invention. ~f lte snowmobile
suspension system ( 10) is shown mounted on a conventional snowmobile ski (
l2).
The conventional snowmobile ski ( l2) includes a gliding section ( 14)
defining a Pair of gliding edges (16), 'the snowmobile ski ( l2) defines a
generally
rectilinear ski rear and section ( 18) and n generally upwardly curved
snowmobile ski
tiont end (2U).
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The snowmobile suspension system (10) is mounted intermediate the ski (12)
and the front end (22) of a conventional snowmobile (only a section of which
is
shown in FIG. 1 ). Typically, the snowmobile suspension system (10) is
attached to a
trunnion-type or other suitable type of connecting component (24) emanating
from
the under surface of the chassis of the snowmobile (22) and preferably somehow
linked to the steering mechanism of the snowmobile (22).
Referring now more specifically to FIG. 5, there is shown in greater details,
some of the components of the snowmobile suspension system (10). The
snowmobile suspension system ( 10) defines a suspension longitudinal axis
(26). The
longitudinal axis (26) device the snowmobile suspension ( 10) into two
symmetrical
half sections. It should be understood that although the embodiment shown
throughout the FIGS, includes two symmetrical half sections. The suspension
system
( 10) could be embodied by a structure including only one half section of the
structure
shown throughout the FIGS. without departing front the scope of the present
invention. In the following description, only one half section will be
described and
the similar components of the other half sections will be denoted by similar
reference
numerals provided with a prime.
The suspension system (10) includes a base rod (28) adapted to be secured to
the top surface of the gliding section (14) of the ski (12). Preferably, the
base rod
(28) has a generally L-shaped cross sectional configuration defining a base
mounting
section (30) and a generally perpendicularly extending base spacing section
(32).
Typically, the base mounting section (30) is provided with mounting
apertures (34) extending therethrough for receiving corresponding mounting
components such as bolts, rivets or the like adapted to affix the base
component (28)
...17
to ski ( 12).
c.
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As shown in FIG. 6, the snowmobile suspension (10), when seen in a side
view, includes a linkage structure having a generally hexagonal configuration
symmetrical about a transversal axis (36).
The suspension system ( 10) also includes a connecting segment (38) for
connecting the suspension system to the snowmobile (22). The connecting
segment
(38) typically includes a pair of connecting arms (40), (40') maintained in a
spaced
relationship relative to each other by a connecting plate (42). Each
connecting arm
(40), (40') is typically provided with a connecting aperture (44) extending
there
through. The connecting aperture (44) is configured and sized for receiving a
trunnion, a bolt or similar liulcing components extending from the snowmobile
(22).
The basc rod (28) and the connecting arm (44) are mechanically coupled to
each other by a pair of scissors-type linkage connections, each including a
first
linkage arm (45) pivotally connected to the base rod (28) by a pivotal
connecting
means (4G) and a second linkage arm (48) pivotally connected to a
corresponding
attachment plate (40) by a pivotal connection (50).
In turn. the first and second linkage arms (45), (48) are pivotally connected
together about their respective distal ends by a pivotal connection (52). The
pivotal
connections (4G), (50) and (52) may take any suitable means. In one embodiment
of
the invention. the pivotal connections (4G), (50) and (52) include pivotal
axles (only
the head of which is shown) extending between symmetrical half sections of the
suspension system ( 1 U) and protectively enclosed within corresponding axle
sleeves
(54).
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In the embodiment shown throughout the FIGS., the first linkage arms (45)
have a generally cylindrical configuration while the second linkage arms (48)
typically have a generally flat configuration and extend between the
synunetrical
half sections.
The snowmobile suspension system (10) further includes a pair of resilient
biasing components (56) extending between the scissors-type linkage assembly
and
the base rods (32). The biasing components (56) are adapted to bias the
suspension
system ( 10) towards its expanded configuration shown throughout the FIGS.,
wherein the base rods (32) and the attachment rods (40) are in a spaced and
parallel
relationship relative to each other.
Each biasing component is typically pivotally attached to the scissors-type
linkage assembly adjacent the pivotal connection (52) by a pivotal connection
(58)
and also attached at an opposite end thereof to the base rods (32) adjacent
the
longitudinal ends thereof by a pivotal connection (60).
The biasing component (56) typically includes a damping component having
a cylinder (62) with an internal chamber filled with hydraulic fluid and a
shock
absorber piston received within the internal chamber and having a piston rod
(G4)
extending therefrom. The biasing component (56) typically further includes an
helicoidal-type spring (66) mounted over the piston and cylinder assembly. The
biasing component (56) is preferably provided with adjustment means for
adjusting
the strength of biasing force and dampening characteristics thereof.
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Abutment means typically taking the form of abutment protrusions
(68) are typically attached to the under surface of the connecting
plate (42) for abutting against the upper surface of the ski (12)
and limiting the range of motion of the suspension system (10) in
situations wherein the suspension system (10) reaches its most
compressed configuration (not shown) wherein the attachment plate
(42) is located adjacent the top surface of the ski (12),
another advantage for the suspension would be a stabizing and(69)
and also an adjustable eccentric for the ski angle (70)
I have a competition racing ski (72).
Sign
Pierre Boudriau, Inventor.
