Rear suspension system for a land vehicle CA

Rear suspension system for a land vehicle – CA 2191008 C – IP.com

Canadian Patent

 

Title (French)

Suspension arriere pour vehicule de transport de surface

Abstract (English)

A suspension assembly for mounting an endless track to a chassis of a snowmobile, the suspension assembly having a pair of pivoting arms centrally mounted to the slide members, or rails, and a weight transfer dynamic compensator capable of compensating for the weight transfer of the snowmobile when the track is pulling on the chassis. The weight transfer dynamic compensator prevents the chassis from rotating excessively with respect to the slide rails during rapid acceleration. Such a rotation of the chassis is detrimental to rider comfort and stability. The suspension assembly is coupled such the rails remain somewhat parallel to the chassis when encountering a bump at either the front of the rails or at the rear of the rails, also enhancing rider comfort and stability. The suspension assembly is coupled by virtue of a limited-translation slide bar at the rear of the suspension assembly and a tension-only member, or pulling belt, located at the front of the suspension assembly. The suspersion assembly having the weight transfer dynamic compensator improves the cornering of the snowmobile by ensuring that there is ample weight on the front skis, especially when accelerating out of a turn.

Inventors

BOIVIN, DENIS [+1] [-1]
BEAUMONT, Q1, CA

BOIVIN, ALAIN
ST-HENRI DE LÉVIS, Q1, CA

Applicants

BOMBARDIER INC.
MONTREAL, Q1, CA

Assignees

BOIVIN, DENIS [+3] [-3]
BEAUMONT, Q1, CA

BOIVIN, ALAIN
ST-HENRI DE LÉVIS, Q1, CA

BOMBARDIER INC.
MONTREAL, Q1, CA

BOMBARDIER RECREATIONAL PRODUCTS INC.
VALCOURT, Q1, CA

Priority

US 632,581 A  15-Apr-1996

Classifications

International (2006.01): B62D 55/108; B62M 27/02
International: B62D 55/104
Cooperative (2013.01.01): B62M 27/02; B62M 2027/026; B62D 55/108
European: B62D 55/108; B62M 27/02

Language of Filing

English

Attorney, Agent or Firm

Osler, Hoskin & Harcourt LLP
CA

Also Published As

CA 2191008 A1

application

Rear suspension system for a land vehicle

Oct-1997

 

US 5860486

patent

Rear suspension system for a land vehicle

Jan-1999

Rear suspension system for a land vehicle – CA 2191008 C – IP.com

2191 OG8
TITLE: REAR SUSPENSION BY8TEM FOR A LAND VEHICLE
FIELD OF THE INDENTION
This invention relates to a single generally
centrally mounted structure in a rear suspension system for a
land vehicle, and more particularly to a weight transfer system
for providing an adjustment between alternative riding
conditions.
BACKGROUND OF THE INVENTION
Rear suspension systems in land vehicles
conventionally comprise apparatus which are mounted to the
chassis of the vehicle in a plurality of locations. Typically,
the rear suspension systems are heavy due to the number of
components in the system, and the impact of the energy absorbed
during the ride of the vehicle is absorbed by the driver.
Several rear suspension systems for snowmobile
vehicles have been patented. For example, U.S. Patent No.
4,826,260 to Plourde discloses a suspension system for an
endless track vehicle, such as a snowmobile. The suspension
system comprises a shock absorber unit being pivotally
connected to a forwardly located crank arm, a strap and a
retainer rod. The retainer rod extends across and is fixed to
a front portion of a pair of lateral slides. The strap limits
1

2191 ~u8
the downward movement of the front portion of the lateral
slides by means of coil springs and a shock absorber unit.
Furthermore, the shock absorber unit exerts a downward force
on both the front and rear portions of the slides.
Another example of a rear suspension system for a
snowmobile vehicle is U.S. Patent No. 4,407,386 to Yasui et al.
This patent discloses a suspension unit comprising a first
shock absorber in a front portion of the rear suspension
system, and a second shock absorber in a rear portion of the
rear suspension system. The first shock absorber is connected
to a proximal end of a guiderail by means of a cross tube,
which is pivotally supported to the vehicle by means of bolts.
The second shock absorber is connected to a distal end of the
guiderail by means of bellcranks and arms. The bellcranks are
pivotally supported on an axle which is journaled in the body
of the snowmobile vehicle. Furthermore, the rear portion of
the rear suspension system comprises a strap for limiting the
maximum vertical travel of the guiderails with respect to the
body of the vehicle at such time as the vehicle is vertically
lifted off the ground. Accordingly, this patent limits the
vertical lift of the guiderails by means of a two sets of shock
absorber units, inc combination with springs, a strap,
bellcranks and arms.
Other examples of patented rear suspension systems
for land vehicles and snowmobiles include: U.S. Patent No.

2

2191008
5,033,572 to Zulawski, U.S. Patent No. 4,787,470 to Badsey,
U.S. Patent No. 4,546,842 to Yasui, U.S. Patent No. 3,913,692
to Lohr et al, Japanese document 62-214065, and Japanese
document 3-157283.
While each of the above described and cited rear
suspension systems for land vehicles function adequately, they
each have certain drawbacks. The major drawback is that the
rear suspension systems are mounted to the underside of the
chassis at both a front and rear portions thereof. The dual
attachment of the prior art suspension systems in some
circumstances add increased weight to the vehicle, reduce
travel of the suspension, and increase the drag on a returning
section of an endless track thereby decreasing the maximum
speed achievable.
Therefore, what is desirable in a rear suspension
system for a land vehicle is a generally centrally mounted
rear suspension system capable of providing improved
acceleration and cornering, an increase in the maximum speed
achievable, a reduction in the weight of the vehicle by
reducing the number of components in the suspension system, and
an improved shock system for decreasing the workload of the
components of the suspension system.

3

2~ 91008
OBJECTB AND SOMMARY OF THE INVENTION
It is therefore the general object of the present
invention to provide a single generally centrally mounted
structure in a rear suspension unit of a land vehicle, such as
snowmobiles and other recreational vehicles.
Another object of the invention is to provide a rear
suspension system for a land vehicle which can provide for an
adjustment between alternative riding conditions during weight
transfer of the vehicle, especially during acceleration and
cornering.
Additionally, it is a further object of the invention
is to reduce the weight of the rear suspension system by
reducing the number of components therein.
Furthermore, it is a further object of the invention
is to transfer the energy impact on the land vehicle toward the
center of gravity of the land vehicle, thereby reducing the
kick back effect, and transferring the energy impact away from
the driver of the vehicle.
In accordance with the invention, these and other
objectives are achieved by providing a suspension system for
the rear portion of a land vehicle comprising a single mounting
structure in a central portion of the suspension system, and

4

CA 02191008 2001-04-20
further providing a caeight dynamic compensator for a_Llowing
adjustment between alternative riding condition.
Thus, as embodied and broadly described herein, the
invention seeks to provide a suspension assembly for a
snowmobile vehicle comprising:
– two substantially parallel and spaced apart elongated
slide members defining a longitudinal axis, connected
together with transversally mounted bridge members, each said
slide member having a first curved ending portion and a
second ending portion f~~r connection of ending wheels;
– two substantially parallel elongated pivoting arms,
each having a first end pivotally connected to a respective
one of said glide members at a first connection point spaced
apart from said first ending portion and a second end adapted
for connection to a vehi~~le chassis;
– a first transversal. rod, adapted for connection to the
vehicle chassis, resi=l_i_ently connected to said slide members
and pivotally connected t.c~ said pivoting arms through another
transversal r_od disposed between the pivoting arms between
said second end and said first end; said another transversal
rod being pivotally connected to the curved portion of the
slide members. through a horizontal rod disposed between said
curved portions of said slide members.
_ , _

CA 02191008 2001-04-20
As embodied and brc:~adly described herein, the invention
also seeks to provide a suspension assembly for a snowmobile
vehicle comprising:
– two substantial=Ly parallel. and spaced apart elongated
~ slide members defir7.inc~ a longitudinal axis, connected
together with transversally mounted bridge members, each said
slide member having a f=first curved ending portion and a
second ending portion for. connection of ending wheels;
– two ,substanti<~lly parallel elongated pivoting arms,
each having a first end. pivotally connected to a respective
one of said slide membe._s at a first connection point spaced
apart from said first ending portion and a second end
adapted for connection tc~ a vehicle chassis;
– a fir:~t transversal rod, adapted for connection to the
vehicle chassis, resiliently connected to said slide members
and pivotally connected to said pivoting arms through another
transversal rod dispose=_d between the pivoting arms between
said second end and sa.i_d first en.d; said another transversal
rod being pivotally c:o:nnected to the curved portion of the
slide member: through a horizontal rod disposed between said
curved portions of s<.~:i.d slide members, said pivoting arms
being resiliently connected to said curved portion of said
slide members.
– 6 –

CA 02191008 2001-04-20
As embodied and broadly described herein, the invention
further seeks to ~>rovide a suspension assembly for a
snowmobile of=hide comprising:
– two substantial~_y parallel and spaced apart elongated
slide members defining a longitudinal axis, connected
together with transve:r_sa:L=Ly mounted bridge members, each said
slide member having a first curved ending portion and a
second ending portion for connecti_Or1 Of ending wheels;
– two subst=antially parallel elongated pivoting arms,
each having a first end pivotally connected to a respective
one of said slide members at a first connection point spaced
apart said first ending portion and a second end adapted for
connection to a vehicle ~~hassis;
– a fir:>t transversal. rod, adapted for connection to the
vehicle chassis, resi:l..ieni=ly connected to said slide members
and pivotally connectE:d t:o said pivoting arms through another
transversal rod disposed between the pivoting arms between
said second end and said first end; said another transversal
rod being pivotally connected to the curved portion of the
slide member~> through a horizontal rod disposed between said
curved portions of said slide members, said first transversal
rod being connected t:o at least one of said second ending
portion of said s.Lide members.

CA 02191008 2001-04-20
BRIEF DESCRIPTION OF THE DRAWINGS
These and other ob=jects, features and advantages of the
invention, a.s well a~; the invention itself, will become
better understood by reference to the following detailed
description when considered in connection with the
accompanying drawings w;zerein:
FIG. 1 is a side view of a snowmobile, including the
rear suspension system a::cording to the present invention;
FIG. 2 is a perspective view of the rear suspension
system;
FIG. 3 is a side view of a snowmobile vehicle, including
a rear suspension sy;~tem and a longitudinal slide bar,
according to the presen~ invention;
FIG. 3a is a side view of a snowmobile vehicle,
including a .rear suspen.ts ion system and a cable, according to
the present invention;
FIG. 4 is a. sidf, view of a snowmobile, displaying the
displacement of the pi~~~~ting arms, according to the present
invention.
_ g _

CA 02191008 2001-04-20
FIG. 5 is ,~ si.c)e view of a second embodiment of the
travel means;
FIG. 6a is a side view of the bracket;
FIG. 6b is a front: elevational view of a support holding
the bracket;
FIG. 7a is a sic.e elevatic>nal view of the secondary
pivoting arm;
FIG. 7b is a front e7_evational view of a support and the
secondary pivoting arrn attachment;
FIG. 8a is a front elevational view of the pulling belt;
FIG. 8b is a right aide view of the pulling belt;
FIG. 9 i.s a side view of the slide bar;
FIG. 10 i:a a side elevational view of the rear
suspension system in accordance with the present invention
showing possible adjustrnf=nts to the bracket;
_ a

CA 02191008 2001-04-20
FIG. 11 is a side elevational view partially showing the
Weight Transf=er Ciynamz.c C:c>mpensator (WT DC) ;
FIG. 12 is a side ~?l.evational view of the slide bar; and
FIG. 13 is a side v.:LE?W Of a .snowmobile showing different
comfort zones, according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although the c~isc:l_osed invention may have broad
applicability, it re1_ates primarily to a rear suspension
system for a land vehicle, and more spec ifically to a land
vehicle with a track, ouch as a snowmobile. The following
description will indicav~~ certain items as occurring in pairs
when only one of thf~ pairs is shown in the accompanying
drawings. It is to be understood that the portion of each
pair which is not shown is identical to the illustrated part
and performs the same function as the illustrated item.
Accordingly, it should be noted that like reference numerals
are used throughout t:h~~ attached drawings to designate the
same or similar eLementt> or components.
Referring now to 1=he drawings, Fig. 1 illustrates a
novel rear suspension sy:>t:em 20 for a snowmobile vehicle 10.
– 10 –

CA 02191008 2001-04-20
The vehicle 10 has a front portion 2, with a forwardly
mounted engine therein (not shown), forwardly mounted travel
means 8, and a rear poi=tion 30, comprising seat area 12,
a

steering means 14, a chassis 16, rearwardly mounted travel

means 18 (also krvown as :;=Lidemembers) , and rear suspension
a

20 (see Figure 3) . 7:’he center of the vehicle
of gravity
22

is in the from:. of the vehicle 10 at 22 as
portion 2

indicated.
The rear su~~pens:ion. system 20 of the vehicle is located
adjacent the rear portion of the land vehicle 10, on an
underside of the chas:~is 16 and is attached to the chassis 16
by means of t:wo bori.zonta7_ bars. A first horizontal bar 40 is
attached to an under:;ide of the chassis directly below the
seat area, a:nd a second horizontal bar 50 is attached to an
underside of the chart>is directly below the steering means
14.
In the following description, the terms “proximal” and
“distal” are with re:Ference to t:he front portion 2 of the
vehicle. The rear suspension system 20, as shown in Fig. 2,
comprises rearwardly mo~.ni~ed travel means 18 having proximal
and distal port=ions. The suspension system 20 further
comprises a pair of s_ruclined primary pivoting arms 60, having
proximal endt> 62 and c~ist:al ends 64. The proximal ends to the
– 11 –

CA 02191008 2001-04-20
primary pivoting arm: 62 a.re attached to the second
horizontal bar ‘~0, an~~ the distal portion of the primary
pivoting arms 64 are cormected to a third horizontal bar 70
at distal portion of the rearwardly mounted travel means 18.
Accordingly, the primary pivoting arms are mounted between
the second horizontal har and the third horizontal bar such
that the primary pivoting arms are inclined at an acute angle
with respect to t:.he r_earwardly mounted travel means, when the
vehicle is in a rest position.
The rear suspension system 20 further comprises a
primary suspension me:~n:~ 80, having a proximal end 82 and a
distal end 84. The pro~;i_mal end of the primary suspension
means 82 is attached to t:he first horizontal bar 40 at a rear
portion of_ the undersio.e of the chassis 16, and a distal end
of the primary suspension means f34 is attached to the third
horizontal bar ’70 at: a distal portion of the rearwardly
mounted travel means 1_8. In a preferred embodiment, the
primary suspension mean,, which is mounted between the first
and third horizontal bar:, is inclined at an acute angle with
respect to the rearwa.rdly mounted travel means when the
vehicle is in a rest position. ‘fhe third horizontal bar 70
also holds together th~~ rearward=Ly mounted travel means. In
sum, the third horizc>ntal. bar 70 acts as a support for the
primary pivoting arms 60 and the primary suspension means
– 12 –

CA 02191008 2001-04-20
80, thereby enabling the primary suspension system to control
the displacement of the rearwardly mounted travel means 18.
Furthermore, due to the structure and support of the
suspension system 20 with respect to the vehicle, the stress
and pressure of the primary suspension means 80 is
transferred t:o the chassis 16 at two relatively near points.
Accordingly, in a preferred embodiment, the chassis comprises
a reinforcing plate 400 to reinforce the chassis, as shown in
Fig. 1.
As further illustrated in Figs. 1 and 2,the distal ends
of the primary pivotin~~ arms 64 are attached to the third
horizontal bar 70 by <~n attachment means 66. The distal ends
of the primary pivoti:nc~ arms 64 have an aperture therein of
approximately 0.750 inches for receiving the attachment means
66. Preferably, the attachment means 66 is a bolt for
securing the primary pivoting arm 60 to the third horizontal
bar 70. Each proximal end of the primary pivoting arms 62 has
an aperture of approximately 1.250 inches for receiving the
second horizontal bar 50 at an underside of the chassis, and
for securing the primary pivoting arm thereto. Preferably,
the primary pivoting arms may be comprised of a metallic
material, such as aluminium. However, instead of aluminum, the
primary pivoting arms may be made from another metallic
material having suitable or similar quality. The
– 13 –

CA 02191008 2001-04-20
configuration of the :primary pivoting arms 60 allows the
rearwardly mounted gravel means 18 to remain generally
horizontal when the rE=_arwardly mounted travel means rises
over a bump. The configuration of the primary pivoting arms
also allows the rear suspension to rock backwards during
initial weight transfer caused by hard accelerations.
The distal end of the primary suspension means 80 is
attached to the third horizontal bar at 70, as shown in FIG.
2. More specifically, the distal ends of the primary
suspension means 84 are attached to a bracket 86 which is
further secured to the third horizontal bar 70. The bracket
86 has an aperture therein, for receiving the third
horizontal bar and securing the primary suspension means 80
thereto. In addition, the proximal end of the primary
suspension means 80 has an aperture having a diameter of
approximately 0.875 inches for securing the primary
suspension means 80 to the first horizontal bar 40. Both the
proximal ends 82 and di;~tal ends 84 of the primary suspension
means 80 are attached tc~ the first and third horizontal bars,
40 and 70 respectively, at an interior portion of the
suspension system. Pref:e rably, the primary suspension means
80 are shock absorbers designed to withstand the weight and
suspension of the vehic7_e.
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Rear suspension system for a land vehicle – CA 2191008 C – IP.com

CA 02191008 2001-04-20
Fig. 6a clearly i7_lustrates a side view of the bracket
86 comprising a plurality of angularly spaced-apart apertures
220, 222 and 224, arranged circumferentially around the third
horizontal bar’s aperture. The apertures are adapted to
receive securing means, such as nuts and bolts, for locking
the bracket 86 into a specific position. The bracket 86 can
further be rotated abou’~ the axis of the third horizontal bar
70, thereby altering the angle of inclination of the primary
suspenion means and securing the primary suspension means
l0 into a specified inclination.
As illustrated in Figs . 2 and 6a, the distal end of the
bracket 86 i.s adjacent t.o a distal portion of the travel
means 18, which further comprise a plurality of apertures
220, 222 and 224. Rotation of the bracket 86 further requires
adjustment and securir:g of the travel means 18 and the
corresponding apertures 220, 222 and 224. The primary
suspension me>.ans 80 m<~y be angularly positioned by attaching
the distal end 84 of the primary suspension means to one of
the apertures 220, 222 and 224. By positioning the primary
suspension means 80, the falling rate of the primary
suspension means is altered, as shown in Fig. 10.
In a further embodiment, the rear suspension system 20
comprises a Weight Transfer Dynamic Compensator (WTDC) for
– 15 –

CA 02191008 2001-04-20
maintaining the front E’nd of the vehicle in close proximity
to the ground surface, thereby providing an improved traction
for the entire vehicle . The features of the WTDC are clearly
illustrated in Fig. ?.The WTDC in combination with the
primary pivoting arms 60 and the primary suspension means 80
provides improved acceleration of the vehicle while
increasing travel of l~he rear suspension system 20. More
specifically, the WTDC further comprises a rod 110, a
secondary pivoting arm 120, and a pair of pulling belts 130,
l0 for providing further adjustment of the primary suspension
means 80 between alternative riding conditions. The rod 110
comprises a first end 1:L2 and a second end 114. The first end
of the rod 112 is attached to the first horizontal bar 40.
The first end of the rod 114 further comprises an aperture
therein for .receiving t:he first horizontal bar therein. The
second end of the rod 114 is attached to the secondary
pivoting arm 120 by means of a bolt. The secondary pivoting
arm 120 further comprises a first end 124 which is attached
to a fourth horizontal bar 75. The proximal end of the
secondary pivoting arm 124 comprises an aperture therein for
receiving the fourth horizontal bar 75 and is secured thereto
at a central area of t:he fourth horizontal bar 75. Finally,
the WTDC comprises a pair of pulling belts 130, one on each
lateral side of the ~;uspension system. The pulling belts
comprises lower ends 132 and upper ends 134. The lower ends
– 16 –

CA 02191008 2001-04-20
of the pulling belts 132 are attached to the rearwardly
mounted travel means 18 at a front portion thereof by means
of a fifth horizontal bar 78, as shown in FIG. 2, and the
upper ends of the pulling belts 134 are attached to the
fourth horizontal bar ’75 by an attachment means. The upper
ends of the pulling belts are attached to the fourth
horizontal bar at an interior portion thereof and adjacent
the primary pivoting ar~rns 60. The pulling belts function to
connect the suspension system 20 with the front portion of
the rear travel means, and insures that the front portion of
the rear travel means remains in close proximity to the
suspension system 20. Accordingly, the pulling belts of the
WTDC system pull down a front portion of the chassis while
maintaining t:he rearwardly mounted travel means 18 to remain
in contact with the around whenever there is a rearward
transfer of weight, notably during rapid forward
acceleration.
Alternatively, the suspension comprises a single pulling
belt 130 and an auxiliary limiting strap which would prevent
components of. the suspension from colliding with the endless
track in the unlikely event that the pulling belt 130 were to
break. The combination of the generally centrally mounted
suspension system and t=he WTDC allows for improved traction
of the vehicle. Fig. :Ll further illustrates the WTDC in
– 17 –

CA 02191008 2001-04-20
combination with the generally centrally mounted suspension

system. More specific:all.y, Fig. 11 is illustrative of the

primary elements of tlue WTDC: secured in two different

positions for differeni~ .riding conditions. The solid lines

represent the positioning of the rod and the secondary

pivoting arm in a standard position for comfortable

recreational touring whi_1_e the shadow lines represent the

position of t:he rod and the secondary
pivoting arm in a more

aggressive, racing position wherein the suspension

compensates for greatar weight transfer by allowing greater

travel in the mechanism..

The rear suspens:ic;n system 20 further comprises a
secondary suspension rr.e<~ns 140, having a proximal end 142 and
a distal end 144 as illustrated in Fig. l.The proximal end of
the secondary suspension means 142 is attached to a fifth
horizontal bar ‘l8, and the distal end of the secondary
suspension means 144 ha,~ing an aperture therein for receiving
a sixth horizontal bar 90 and being attached thereto. The
secondary suspension rr~ean~; 140 of the rear suspension system
20 may be a shock absc» ~ber. The secondary suspension means
140 work t=o <~bsorb shocks during movement or vertical weight
transfer of the vehicle.
– 1f3 –

CA 02191008 2001-04-20
In an alternative’ embodiment, the suspension system
comprises a longitudinal slide bar 150 located at a rear
portion of said vehicle, with the secondary suspension means
140 at a proximal portion of the vehicle being removed as
illustrated in Fig. 3.Th.e longitudinal slide bar 150 further
comprises a proximal a=nd 152 and a distal end 154. The
proximal end of the elide bar 152 has an aperture therein,
having a diameter of approximately 0.875 inches for receiving
the first horizontal bar 40 and securing the slide bar 150
l0 thereto. The distal end of the slide bar 154 has an elongated
aperture therein, having a width of approximately 1.375
inches and a radius ~~f curvature of approximately 1.000
inches, for receiving an eighth horizontal slide bar 94
adjacent a set of rear wheels of said vehicle at 300 in Fig.

5. In a preferred embodiment, the slide bar has a length of
24.50 inches, a width at: a midsection of 1.50 inches, and a
depth of 0.375 inches. As shown in Figs. 3 and 5,when the
rear suspension system 20 comprises the slide bar 150, the
rearwardly mounted travel means 18, such as a pair of
longitudinal slides 160, comprise a plurality of apertures at
300 for attaching the slide bar 150 to the rearwardly mounted
travel means 18. Figs. 12 and 13 further illustrate the
attachment of the sl.id.e bar 150 to the travel means. The
aperture at the distal end of the slide bar may be secured
without a gap (i.e. for a tight fit) between the aperture at
– 19 –

CA 02191008 2001-04-20
the distal end of the slide bar 154 and the attachment to the
longitudinal slide 160 at 300, as shown in Fig. 12. In this
arrangement, the slide bar cannot translate longitudinally.
Such a configuration provides for a stiffer riding of the
slide bar and the vel-iicle, as shown in zone 1 of Fig. 13.
Alternatively, the aperture at the distal end of the slide
bar 150 may be secured with a gap (i.e. in a sliding fit) of
0.250 inches between the aperture at the distal end of the
slide bar 154 and the attachment to the slide at 300, as
shown in Fig. 12. In this arrangement, the slide bar can
translate longitudinal_l~y within the elongated aperture. Such
a configuration provider for a softer riding of the slide bar
and the vehicle, as shown in zone 2 of Fig. 12. The
longitudinal slide bar 150 functions in a tension mode only,
and extends from the eighth horizontal bar 94 to the first
horizontal bar 40. They eighth horizontal bar 94 comprises
eccentric bolts for rotating the eighth horizontal bar and
thus adjusting the stiffness of the suspension system 20.The
slide bar 150 is held in tension, and maintains a constant
distance from the rear wheels 6 to the first horizontal bar
40, thereby transferring the force of an impact on the
suspension system to t:he primary suspension means 80. In a
preferred embodiment, the longitudinal slide bar 150 may be
comprised of a thermoplastic type material. However, instead
of a thermoplastic mat.=vial, the slide bar 150 may be made
– 20 –

CA 02191008 2001-04-20
from another material having suitable or similar quality and
strength, provided that: the material of the slide bar 150
enables it to accommodate the force of the suspension system
in a tension mode.
S
In an alternative embodiment, the slide bar 150 may be
replaced by a cable 150a or a strap (as illustrated in Fig.
3a) comprised of a material having suitable or similar
strength as that provided by the slide bar 150.
The forwardly and r_earwardly mounted travel means are
shown in the’ attached drawings as a pair of longitudinal
slides 160. In a pre:f:erred embodiment, the longitudinal
slides 160 comprise a ~~topper 162 at a proximal end of the
slide. The stopper 162 is preferably comprised of a rubber
material and is located on a top surface of the slide
adjacent the proximal end, so as to prevent the proximal
portion of the slide. from damaging the chassis and the
suspension system dur_~ng full extension of the primary
pivoting arms 60 and the primary suspension means 80. In
addition, the primary pivoting arms 60 comprise a stopper 68
at a midsection and on a top surface of the primary pivoting
arms. The stopper 68 is preferably comprised of a rubber
material, so as to prevent the primary pivoting arms from
damaging the chassis and the suspension system during full
– 21 –

CA 02191008 2001-04-20
extension of the primary pivoting arms and the suspension
system 20. Accordingly, stopper 162 and stopper 68 may be
made from another material. having suitable or similar quality
and strength to a rubber type material.
Figs. 1, 2 and 3 illustrate in detail a preferred
embodiment wherein t:h~= forwardl.y and rearwardly mounted
travel means 18 are in the form of longitudinal slides 160 of
a snowmobile. The travel means further comprise a flexible
endless track 164, for supporting the chassis, and a
plurality of wheels displaced along the length of the travel
means for enabling the endless track to move. The
longitudinal slides 16C are placed on an inside surface of
the endless track and support the rear suspension system 20.
In a preferred embodiment, the longitudinal slides may be
comprised of a metall_Lc type material, such as aluminum.
However, instead of aluminum, the longitudinal slides 160 may
be made from another metallic material having suitable or
similar quality and strength. The longitudinal slides 160
preferably comprises ~~ thickness of approximately 0.375
inches. An underside potion of the longitudinal slide, which
is in direct contact. with the endless track 164 of the
suspension system, preferably has a width of approximately
1.000 inches and a dept;lz of approximately 0.187 inches. The
underside portion of t:he slide is also comprised of a
– 22 –

CA 02191008 2001-04-20
metallic material, and preferably of an aluminum type
material. However, instead of aluminum, the underside portion
of the slide 160 may be comprised from another material
having a suitable or si.mi:lar quality and strength. The slide
further comprises a plurality of apertures disposed
throughout the length of the slide for receiving a plurality
of horizontal. bars fo:r attaching the longitudinal slides 160
to rear suspension system 20 of the vehicle 10.
As shown in Fig. 4, the centrally mounted primary
pivoting arms 60 of the rear suspension system provides for
improved maneuverabilit~~ of the rear suspension when compared
to the prioz- art. In a preferred embodiment, the primary
pivoting arms 60 are c~~mprised of a metallic type material,
and preferably of an aluminum material. However, instead of
aluminum, the primary pivoting arms 60 may be made from
another material having suitable or similar quality. The
arrangement of the primary pivoting arms 60 permits the
rearwardly mounted t:r~~vel means to rise vertically and
generally horizontally when bumps are encountered. The
primary pivoting arms 60 have a length of approximately 27.00
inches, a maximum width of 3.50 inches, and a depth of 0.25
inches. At a proximal E=_nd of the pivoting arms 62, there is
an aperture having a r<~dius of 1.250 inches for receiving a
second horizontal bar 50 and securing the primary pivoting
– 23 –

CA 02191008 2001-04-20
arm 60 to the chassis of the vehicle. A distal end of the
primary pivoting arm 64 comprises an aperture having a
diameter of approximate:Ly 1.50 inches for receiving the third
horizontal bar 70 and securing the distal end of the primary
pivoting arms 64 thereto.
Fig. 4 shows the primary pivoting arms 60 in several
different positions for a given snowmobile vehicle, wherein
each position depicted is dependent upon the weight being
applied to t=he suspen:~ion system 20. When the suspension
system is at rest, the vertical distance between a top
surface of the rear bumper 4 of the vehicle and the distal
end of the primary pivoting arms 64 is 19.892 inches.
However, when the suspension system is active and at its
maximum flexibility, the primary pivoting arms are in a
relatively horizontal position allowing for a vertical
clearance of at least. 11.500 inches from the ground to the
top surface of the rear bumper 4 of the vehicle. As is
further illustrated in shadow lines in Fig. 4, track tension
creates a compression of the rearward portion of the
suspension system. The pulling belts are able to pull down a
front portion of the chassis so that the rearwardly mounted
travel means remain generally horizontal and remain in
contact with the ground thereby maintaining good traction.
– 24 –

CA 02191008 2001-04-20
For purposes of completeness, the following is a chart
of the angle of displacement of the primary pivoting arms 60,
and the vertical distance from the distal end of the primary
pivoting arms 60 to a top horizontal surface of the rear
bumper 4 of the particular land vehicle given in this
example:
Angle of displacement Clearance

(degrees) (Inches)

18.92 8.392

26.52 12.219

34.43 16.784

When the suspension system 20 is in full extension, the
l0 minimum angle of displacement from the distal end of the
primary pivoting arm is 18.92 degrees, and when the
suspension system is at rest, the maximum angle of
displacement from the distal end of the primary pivoting arm
is 34.43 degrees.
The above description is of a generally centrally
mounted rear suspension system for a land vehicle, such as a
snowmobile. In an alternative embodiment, the suspension
system may be in the form of a kit separate from the vehicle
as a whole. The kit may be assembled and attached to a
conventional snowmobile and used to modify an already
existing suspension syst=em.
– 25 –

CA 02191008 2001-04-20
Although the present: invention has been described in
connection with preferred embodiments thereof, it will be
appreciated by those skilled in the art that additions,
deletions, modifications, and substitutions not specifically
described may be made without departing from the spirit and
scope of the invention as defined in the appended claims and
the scope should not b~~ limited to the dimensions indicated
hereinabove.
– 26 –

(Source: IFI)

Rear suspension system for a land vehicle – CA 2191008 C – IP.com

1. A suspension assembly for a snowmobile vehicle comprising:
– two substantially parallel and spaced apart elongated
slide members defining a longitudinal axis, connected together
with transversally mounted bridge members, each said slide
member having a first carved ending portion and a second ending
portion for connection of ending wheels;
– two substantially parallel elongated pivoting arms, each
having a first end pivotally connected to a respective one of
said slide members at a first connection point spaced apart from
said first ending portion and a second end adapted for
connection to a vehicle chassis;
– a first transversal rod, adapted for connection to the
vehicle chassis, resiliently connected to said slide members and
pivotally connected to said pivoting arms through another
transversal rod disposed between the pivoting arms between said
second end and said first end; said another transversal rod
being pivotally connected to the curved portion of the slide
members through a horizontal rod disposed between said curved
portions of said slide members.

2. A suspension assembly as defined in claim 1, wherein said
first transversal. rod, is resiliently connected to said slide
members at said first connection point.

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3. A suspension assembly as defined in claim 1, wherein said
first transversal rod is resiliently connected to said slide
members through a transversal rod different from said another
transversal rod.
4. A suspension assembly as defined in claim 1, wherein said
first transversal rod is resiliently connected to said slide
members with at least one resilient member.
5. A suspension assembly as defined in claim 4, wherein said
resilient member is a shock absorber.
6. A suspension assembly as defined in claim 1, wherein the
connection between said first transversal rod and said another
transversal rod is provided with a two-part linking member.
7. A suspension assembly as defined in claim 1, wherein the
connection between said another transversal rod and said
horizontal rod is provided with a strap.
8. A suspension assembly for a snowmobile vehicle comprising:
– two substantially parallel and spaced apart elongated
slide members defining a longitudinal axis, connected together
with transversally mounted bridge members, each said slide
member having a first curved ending portion and a second ending
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portion for connection of ending wheels;
– two substantially parallel elongated pivoting arms, each
having a first end pivotally connected to a respective one of
said slide members at a first connection point spaced apart said
first ending portion and a second end adapted for connection
to a vehicle chassis;
– a first transversal rod, adapted for connection to the
vehicle chassis, resiliently connected to said slide members and
pivotally connected to said pivoting arms through another
transversal rod disposed between the pivoting arms between said
second end and said first end; said fourth rod being pivotally
connected to the curved portion of the slide members through a
horizontal rod disposed between said curved portions of said
slide members, said pivoting arms being resiliently connected
to said curved portion of said slide members.

9. A suspension assembly as defined in claim 8, wherein said
pivoting arms are resiliently connected to said curved portion
of said slide members with at least one resilient member.
10. A suspension assembly as defined in claim 9, wherein said
resilient member is a shock absorber.
11. A suspension assembly as defined in claim 8, wherein said
first transversal rod, is resiliently connected to said slide

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members at said first connection point.

12. A suspension assembly as defined in claim 8, wherein said
first transversal rod is resiliently connected to said slide
members through a transversal rod different from said another
transversal rod.
13. A suspension assembly as defined in claim 8, wherein said
first transversal rod is resiliently connected to said slide
members with at least one resilient member.
14. A suspension assembly as defined in claim 13, wherein said
resilient member is a shock absorber.
15. A suspension assembly as defined in claim 8, wherein the
connection between said first transversal rod and said another
transversal rod is provided with a two-part linking member.
16. A suspension assembly as defined in claim 8, wherein the
connection between said another transversal rod and said
horizontal rod is provided with a strap.
17. A suspension assembly for a snowmobile vehicle comprising:
– two substantially parallel and spaced apart elongated
slide members defining a longitudinal axis, connected together

-30-

with transversally mounted bridge members, each said slide
member having a first curved ending portion and a second ending
portion for connection of ending wheels;
– two substantially parallel elongated pivoting arms, each
having a first end pivotally connected to a respective one of
said slide members at a first connection point spaced apart from
said first ending portion and a second end adapted for
connection to a vehicle chassis;
– a first transversal rod, adapted for connection to the
vehicle chassis, resiliently connected to said slide members and
pivotally connected to said pivoting arms through another
transversal rod disposed between the pivoting arms between said
second end and said first end; said another transversal rod
being pivotally connected to the curved portion of the slide
members through a horizontal rod disposed between said curved
portions of said slide members, said first transversal rod being
connected to at least one of said second ending portion of said
slide members.

18. A suspension assembly as defined in claim 17, wherein said
first transversal rod being connected to at least one of said
second ending portion of said slide members with a sliding type
connection.
19. A suspension assembly as defined in claim 17, wherein said
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connection is provided with an elongated slide bar connected on
a first end to said first rod and on a second end to said slide
member.

20. A suspension assembly as defined in claim 17, wherein said
first transversal rod, is resiliently connected to said slide
members at said first connection point.
21. A suspension assembly as defined in claim 17, wherein said
first transversal rod is resiliently connected to said slide
members through a transversal rod different from said another
transversal rod.
22. A suspension assembly as defined in claim 17, wherein said
first transversal. rod is resiliently connected to said slide
members with at least one resilient member.
23. A suspension assembly as defined in claim 22, wherein said
resilient member is a shock absorber.
24. A suspension assembly as defined in claim 17, wherein the
connection between said first transversal rod and said another
transversal rod is provided with a two-part linking member.
25. A suspension assembly as defined in claim 17, wherein the
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connection between said another transversal rod and said horizontal rod is
provided with a
strap.
33

(Source: IFI)