Motor vehicles – Including one or more ski-like or runner members – With at least one surface-engaging propulsion element
Reexamination Certificate
2001-06-11
2003-12-02
Morris, Lesley D. (Department: 3611)
Motor vehicles
Including one or more ski-like or runner members
With at least one surface-engaging propulsion element
C280S124128
Reexamination Certificate
active
06655487
ABSTRACT:
FIELD OF THE INVENTION
The present invention concerns generally concerns the construction of vehicles such as snowmobiles, all terrain vehicles (“ATVs”), and other similar vehicles. More specifically, the present invention concerns the construction of a front suspension with three-ball joints that are connected to a support leg for the vehicle.
DESCRIPTION OF RELATED ART AND GENERAL BACKGROUND
Snowmobiles, ATVs, wheeled vehicles, and other related vehicles (hereinafter, “recreational vehicles,” although the appellation should not be construed to be limited only to the vehicles or type of vehicles described herein) often function under similar operating conditions. Despite this, snowmobiles, ATVs, wheeled vehicles, and other recreational vehicles do not share a common design approach or a commonality of components. This is due, in large part, to the different stresses and strains (mainly at the extremes) that the different vehicles experience during routine operation.
As a general rule, the prior art includes few, if any, examples of a common design approach to ATVs, wheeled vehicles, and snowmobiles. Primarily, this appears to be due to the fact that these vehicles were designed traditionally from radically different starting points. For example, there has not been a common design approach to the front suspensions that are incorporated into snowmobiles, ATVs, and other wheeled vehicles even though there are common design parameters for each of these types of vehicles.
In the case of snowmobiles, two front suspensions are well known in the art. The first is typically referred to as a “trailing arm suspension” and is commonly found on snowmobiles manufactured by Bombardier Inc. of Montreal, Quebec, Canada. The second is known as a double A-arm suspension and is typically found on snowmobiles manufactured by Arctic Cat of Thief River Falls, Minn., USA.
A prior art trailing arm front suspension is generally depicted in
FIGS. 1
,
3
, and
36
. As illustrated in detail in
FIG. 36
, a trailing arm suspension
442
includes a trailing arm
444
(which is also referred to as a swing arm). Trailing arm
444
connects between a pivot
446
, which connects to engine cradle
56
, and a front leg
448
. Front leg
448
connects ski
20
to engine cradle
56
. A shock absorber
450
connects between engine cradle
56
and trailing arm
444
to dampen the forces associated with the travel of snowmobile
12
over uneven terrain. Steering control of snowmobile
12
is provided by a mechanical link between skis
20
and handlebars
82
.
A typical double A-arm suspension
452
is illustrated generally in
FIGS. 37-40
. The illustration of double A-arm suspension
452
that is shown in
FIGS. 37-38
was reproduced from U.S. Pat. No. 5,664,649, which purports on its face to be assigned to Arctic Cat. As shown, double A-arm suspension
452
includes an upper A-arm
454
and a lower A-arm
456
. Both A-arms
456
,
454
are connected to front leg
458
and permit front leg
458
to move vertically as snowmobile
460
travels over uneven terrain. A shock absorber
462
, which is connected between the body of snowmobile
460
and lower A-arm
456
, dampens the forces applied to skis
464
as snowmobile
460
travels over the ground. Alternatively, it is known to connect shock absorber
450
directly to front leg
458
, as illustrated in FIG.
39
.
Since upper and lower A-arms
454
,
456
are connected to front leg
458
through pins (or bolts)
466
,
468
, front leg
458
cannot rotate around its vertical centerline. Therefore, front leg
208
cannot be used to turn ski
464
. Instead, a steering shaft
470
extends through a hole
472
bored through front leg
458
. Steering shaft
470
is connected to handlebars
474
through a mechanical linkage
476
. As handlebars
474
are rotated, steering shaft
470
rotates in the direction of the arrow
478
shown in FIG.
40
. Since steering shaft
470
is connected to ski
464
through a pin or bolt
480
, as steering shaft
470
rotates, ski
464
turns.
While both of these front suspensions provide adequate control and steering of the respective snowmobiles on which they are installed, neither provides a simple construction for a front suspension.
In the case of the trailing arm suspension, the trailing arm
444
adds additional components to the system. The additional components add to the manufacturing cost and to the complexity of snowmobile
12
. Moreover, the additional components increase the overall weight of snowmobile
12
.
In the case of double A-arm suspension
452
, the same is true. In this case, however, the complexity of the system and the weight of the components are particularly pronounced. For example, it is estimated that the weight of front leg
458
is about twice that of front leg
448
of trailing arm suspension
442
. This is attributable to the individual components that comprise front leg
458
, which is usually constructed as an aluminum extrusion. Steering shaft
470
, which is typically made of steel and forms a part of front leg
458
, is disposed through front leg
458
to provide steering for snowmobile
460
. Steering shaft
470
adds to the overall weight of front suspension
452
.
The complexity of front leg
458
is attributable not only to the design of the component but also to the considerable amount of machining and assembly that are required after front leg
458
is extruded. For example, hole
472
must be drilled through front leg
458
to accommodate steering shaft
470
. Moreover, three holes
482
,
484
, and
486
must be drilled through front leg
458
to accommodate upper A-arm
452
, lower A-arm
454
, and shock absorber
462
. In addition, while not shown in the drawings, a hollow shaft is welded between the sides of front leg
458
to accommodate the pins (such as pin
466
) that connect upper A-arm
454
, lower A-arm
456
, and shock absorber
462
to front leg
458
. A bushing is usually placed within the hollow shaft to facilitate pivoting motion of the pins inserted therethrough. All of this adds considerably to the overall weight and construction cost of snowmobile
460
.
In the manufacture of snowmobiles (as with the construction of any product), one goal is to reduce the weight of the final vehicle. Another object is to reduce the complexity of the vehicle. Both goals ultimately reduce the overall manufacturing cost of the vehicle.
The inventors of the present invention recognized that a hybrid approach between the two prior art suspensions might accomplish both of these objectives. Namely, a hybrid approach might provide both a more simplified construction and a lower weight for a front suspension. In addition, the inventors recognized that such a hybrid approach might provide a front suspension that could be applicable both to snowmobiles, wheeled vehicles, ATVs, and other recreational vehicles.
No prior art front suspension, however, offers or suggests a practicable approach.
SUMMARY OF THE INVENTION
In view of the foregoing, one object of the present invention is to exploit the design elements of a snowmobile that are easily and readily transferred to the design of a wheeled vehicle, such as an ATV, based on a basic frame structure.
To that end, one object of the present invention is to provide a front suspension that incorporates a double A-arm construction which does not require a heavy, front leg with a steering shaft disposed therein.
It is another object of the present invention to provide a front suspension for a snowmobile, wheeled vehicle, or ATV that does not require a trailing arm.
Accordingly, it is an object of the present invention to provide a front suspension with a light-weight leg that is rotatable about a vertical axis.
It is still another object of the present invention to provide a suspension for a vehicle that includes an upper A-arm and a lower A-arm. The suspension further includes a leg with a vertical axis that is rotatably connected to both the upper A-Arm and the lower A-arm. A mechanical link is rotatably connected to the leg so that movement of the mechanical
Cote Mario
Fecteau Berthold
Girouard Bruno
Mallette Bertrand
Bombardier Inc.
Morris Lesley D.
Winner Tony
LandOfFree
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