Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02411964 2002-11-15
SNOWMOBILE WITH ACTIVE RIDER POSITIi)N1NG
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention concerns the overall design and construction of a
snowmobile. More
particularly, the present invention concerns the construction and arrangement
of various
snowmobile components that determine the riding position of a rider thereon.
2. Description of Related Art
Unless otherwise expressly stated, all dimensions for snowmobile riders are
based on a
standard rider, who is defined by a 50'h-percentile United States human male
who weighs 78
kilograms (174.8 lb.) and has the dimensions shown in FIGS. 6 and 7. As would
be obvious to
one of ordinary skill in the art, the dimensions illustrated in FIGS. 6 and 7
are in centimeters with
the middle value representing the SOt~'-percentile U.S. human male. Similarly,
all positioning of
the riders is based on the positioning of a standard rider on a snowmobile in
a standard position.
In the standard position, the rider is seated on the seat, is holding the
steering device with his
hands, and has his feet on the footrest. Accordingly, the rider has the
position shown in the
Figures (i. e., in the approximate position of a rider a few seconds after
starting the vehicle,
heading straight ahead on a flat terrain).
Conventional snowmobiles share a common construction: they combine features
and
elements so that the rider sits in a generally upright position in a location
toward the rear of the
vehicle. When seatod in this fashion, the rider sits a considerable distance
behind the center of
gravity of the vehicle (i. e., the center of gravity of the combination of the
vehicle and the rider),
which is located at or in proximity to the axis of the forward-most axle of
the drive track.
When a snowmobile encounters a bump as it travels over the ground, the vehicle
naturally
tends to pivot about its center of gravity. Accordingly, the further the rider
is positioned from the
center of gravity of the vehicle, tha more strongly the rider will feel each
bump as he passes over
it. This occurs because the vehicle acts as a lever that amplifies the
magnitude of the forces
transferred from bumps on the ground to the rider. In the case of the
conventional snowmobile,
CA 02411964 2002-11-15
because the rider is positioned toward the rear of the vehicle, the rider is
acutely aware of this
phenomenon.
As is explained in greater detail below, the positioning of the rider on the
conventional
snowmobile impairs the rider's ability to easily raise and lower himself on
the snowmobile. The
rider's impaired mobility limits his ability to actively position himself
~i.e., position himself so as
to absorb bumps, lean into turns, etc.),
Accordingly, while the positioning of the rider on the conventional snowmobile
is entirely
adequate for enjoying the sport of snowmobiling, a need has arisen for a
snowmobile where the
rider's position is improved to minimize the effect of the vehicle's movement
on the rider as it
passes over uneven terrain.
SUMMARY OF THE IiWENTION
The present invention improves upon the conventional design by repositioning
the rider
on the vehicle and redesigning the layout of the vehicle to minimize the
effect of the vehicle's
movement on the rider as they pass over uneven terrain.
As would be understood by a person skilled in the art, a snowmobile has a
center of gravity
without the rider, and may have a different center of gravity with the rider.
In the context of the
present application it should be understood that the expression "center of
gravity of a
snowmobile" refers the center of gra ity of a snowmobile with the rider,
unless the contrary is
indicated. Further, it should be understood that in the context of the present
invention it is
assumed that the vehicle is in running condition and is full of fuel.
One or more embodiments of the present invention provide a snowmobile with a
frame
that includes a tunnel, an engine disposed on the frame, a drive track
disposed below and
supported by the tunnel and connected operatively to the engine for propulsion
of the
snowmobile, and two skis disposed an the frame. A straddle seat is disposed on
the frame, The
seat is dimensioned to support a standard rider in a standard position, the;
standard rider having
the dimensions and weight of a SOs'-percentile human male. A footrest is
supported by the frame
to support the rider's feet, A steering device is disposed on the frame. The
steering device is
operatively connected to the two skis for steering the snowmobile. The
footrest, straddle seat,
and steering device are constructed and arranged such that when the standard
rider is in the
standard position, the hips are disposed above the knees.
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CA 02411964 2002-11-15
According to a further aspect of these embodiments, when the standard rider is
in the
standard position, the hips are disposed above the knees by a vertical
distance that is preferably
between 0 and 20 cm, and is more preferably between 5 and 15 cm.
According to yet a further aspect of these embodiments, the footrest, straddle
seat, and
steering device are constructed and arranged such that when the standard rider
is in the standard
position, the hips are disposed behind the ankles by a horizontal distance
that is preferably
between 5 and 40 cm, is more preferably less than 30 cm, and is even more
preferably less than
25 cm.
According to yet a further aspect of these embodiments, the footrest, straddle
seat, and
steering device are constructed and arranged such that when the standard rider
is in the standard
position, the rider's hips are positioned behind the steering position by a
horizontal distance that
is preferably less than 70 cm, is more preferably betwesr! 20 and 60 cm, is
even more preferably
between 35 and 60 cm, is even more preferably between 40 and 60 cm, and is
even more
preferably about 50 em.
One or more embodiments of the present invention provide a snowmobile with a
frame
that includes a tunnel, an engine disposed on the frame, a drive track
disposed below and
supported by the tunnel and connected operatively to tho engines for
propulsion of the
snowmobile, and two skis disposed on the frame. A straddle seat is disposed on
the frame. The
seat is dimensioned to support a standard ridex in a standard position, the
standard rider having
the dimensions and weight of a 50-percentile human male. A footrest is
supported by the frame
to support the rider's feet. A steering device is disposed on the frame
forward of the seat. The
steering device is operatively connected to the two skis for steering the
snowmobile. The
footrost, straddle seat, and steering device are constructed and arranged
.such that when the
standard rider is in the standard position, the ankles are disposed behind the
knees.
According to a further aspect of embodiments of the present invention, when
the standard
rider is in the standard position; the ankles are disposed behind the knee::
by a horizontal distance
that is preferably between 5 and 30 cm, and is more preferably between 15 and
25 cm.
According to a further aspect of embodiments of the present invention, the
footrest,
straddle seat, and steering device are constructed and arranged such that when
the standard rider
is in the standard position, the knees are disposed below the steering
position preferably by at
least 10 cm, more preferably by at least 20 cm, and even more preferably by at
least 25 cm.
CA 02411964 2002-11-15
According to a further aspect of embodiments of the present invention, the
sleeting device
defines a steering position. The footrest, straddle seat, and steering device
are constructed and
arranged such that when the standard rider is in the standard position, the
ankles are disposed
behind the steering position. The ankles are preferably disposed behind the
steering position by
between 5 and 50 cm, are more preferably disposed behind the steering position
by at least 15
cm, and are even more preferably disposed behind the steering position by at
least 25 cm.
According to a further aspect of embodiments of the present invention, the
footrest,
straddle seat, and steering device are constructed and arranged such that when
the standard rider
is in the standard position, the hips are disposed above the knees.
The hips are preferably disposed behind the ankles by a horizontal distance of
less than 30 cm.
According to a further aspect of embodiments of the present invention, the
steering device
defines a steering position. The footrest, straddle scat, and steering device
are constructed and
arranged such that when the standard rider is in the standard position, the
hips are disposed below
the steering position by a vertical distance that is preferably between 0 and
30 cm, and is more
preferably between 10 and 25 cxn.
One or more embodiments of the present invention provide a snowmobile that
includes a
frame that includes a tunnel, an engine disposed on the frame, a drive track
disposed below and
supported by the tunnel and connected operatively to the engine for propulsion
of the
snowmobile, two skis disposed on the frame, a straddle seat disposed on the
frame behind the
engine, a footrest supported by the frame, and a steering device disposed on
the frame. The
steering device operatively connects to the two skis for steering the
snowmobile. The steering
device defines a steering position that is disposed forwardly from a forward
most portion of the
footrest.
According to a further aspect of embodiments of the present invention, the
steering
position is disposed in front of the forward most portion of the footrest by a
horizontal distance of
at least 5 cm.
One or more embodiments of the present invention provide a snowmobile that
includes a
frame that includes a tunnel, an engine disposed on the frame, a drive track
disposed below and
supported by the tunnel and connected operatively to the engine for propulsion
of the
snowmobile, and two skis disposed on the frame. A straddle seat is disposed on
the frame behind
the engine and defines a seat position on the snowmobile. A footrest is
supported by the frame
4
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CA 02411964 2002-11-15
and define a footrest position on the snowmobile. A steering device is
disposed rni the frame
and defines a steering position on the snowmobile. The steering devic;e
operatively connects to
the two skis for steering the snowmobile. The footrest position, steering
position, and seat
position of the snowmobile are arranged with respect to one another to define
an active riding
geometry.
According to a further aspect of embodiments of the present invention, the
footrest
position is disposed 9 em below the ankle of a standard rider, Similarly, the
seat position is
disposed 9 cm below the hips of the standard rider. Furthermore, the
snowmobile includes a knee
position, which is disposed in the same area as the rider's knees at a
narrowed portion of the seat.
The relative positions of steering position, footrest position, seat position,
and knee position can
be determined by reference to the relative positions of the steering position
and the hips, knees,
and ankles ofthe standard rider.
These aspects as well as additional andlor alternative aspects, objects, and
features of the
embodiments of the present invention will become apparent from the following
description.
BRTEF DESCRIPTION OF THE DRAWINCxS
For a better understanding of the present invention as well as other objects
and fixrther
features thereof, reference is made to the following description which is to
be used in conjunction
with the accompanying drawings, where:
FIG. 1 is a side view illustration of a conventional snowmobile, showing the
traditional
positioning of a rider thereon;
FIG. 2 is a side view of a snowmobile according to the teachings of the
present invention,
showing the positioning of a rider thereon;
FIG: 3 is a side view illustration of the position of the rider on the
snowmobile illustrated in FIG.
2;
FIG. 4 is a top view representation of the snowmobile illustrated in FIG, 2,
showing the radius of
travel of the steering device through a full range of motion;
FIG. 5 is a perspective view of the frame of the snowmobile of FIG. 2;
FIG. 6 illustrates a front elevational view of a standard rider; and
FTG. 7 illustrates a side elevational view of the standard rider illustrated
in FIG. 6.
DETAILED DESCRIPTION OF PREFBRRED EMBODIMENTS
CA 02411964 2004-05-25
'Throughout the description of the various embodiments of the present
invention,
reference will be made to various elements, the construction of which is
readily known to those
skilled in the art. Accordingly, an exhaustive description of each and every
component is not
provided, only a description of those elements required for an understanding
of the present
invention.
FIG. 1 illustrates a conventional snowmobile 10 (that sold by Bombardier Inc.
of
Montreal, Canada, under the trademark SKI-DOOTM, model MXZTM, model year
1999), which
has a forward end 11 and a rearward end 13, which are defined consistently
with the travel
direction of the vehicle 10. Conventional snowmobile 10 includes a body 12
(i.e., the exterior
upper portions) and a frame 14. An enginelmotor 15 is carried by frame 14 at
its forward end. In
addition, two skis 16 are attached to the forward end of frame 14 through a
suspension system 18.
A drive track 20 is disposed under frame 14 and is connected operatively to
the engine/motor 15
for propulsion of the vehicle 10.
At the front of frame 14, snowmobile 10 includes fairings 22 that enclose the
engine 15 to
protect it and to provide an external shell that can be decorated so that the
snowmobile 10 is
aesthetically pleasing. Typically the fairings 22 comprise a hood and a bottom
pad (neither of
which have been individually identified). A windshield 24 may be connected to
fairings 22 near
the forward end 11 of snowmobile 10. Windshield 24 acts as a windscreen to
lessen the force of
the air on rider 26 when snowmobile 10 is moving.
A seat 28 extends from rearward end 13 of snowmobile 10 to the fuel tank 29. A
steering
device 32, such as a handlebar, is positioned forward of rider 26 and behind
the engine 15. Two
footrests 34 are positioned on either side of seat 28 to accommodate the
rider's feet 46.
When seated, the standard rider 26 will be positioned so that his hands grasp
steering
device 32 at steering position 36. Moreover, rider 26 will be seated so that
the center of his torso
42 is above seat position 30. When seated in this manner, the rider's feet 46
naturally will be
placed at footrest position 38. Positioned in this manner, the rider's center
of gravity 40 will be
located just forward of the rider's stomach, offset from the center of the
rider's torso 42. The
rider's center of gravity 40 is offset forwardly from the center of the
rider's torso 42 because the
rider's arm and legs are disposed forward of the rider's torso 42 when rider
26 is in the driving
position.
6
CA 02411964 2002-11-15
For conventional snowmobile 10, the rider's center of gravity 40 is behind the
center of gravity
of the snowmobile 44 (i.e., the center of gravity of the snowmobile with the
rider). The center of
gravity of the snowmobile 44 is located on or near the forward-most .axle 45
of drive track 20.
While the forward-most axle of drive track 20 is not shown, those skilled in
the art will readily
appreciate that it is located at or near the position labeled as the center of
gravity of the vehicle
44. In addition, footrests 34 are inclined upwardly from the horizontal so
that the rider's feet 46
are irt a comfortable position when rider 26 is seated on snowmobile 10.
Consequently, the
bottom of the rider's foot 46 (or the sole of his footwear) forms about a 20
degree angle with a
horizontal plane.
For conventional snowmobile 10, the positioning of these various components
and
elements creates a situation where the standard rider 26 is seated in a
relatively upright position
toward the rear of the vehicle 10. As shown in FIG. 1, with the rider's feet
4G positioned on
footrests 34, the rider's knees 48, which are defined by the knee joints, are
positioned close to the
steering position 36 where the rider's hands 54 are located. The rider's hip
52, which is defined
by the hip joint, is disposed below the rider's knee 48. The rider's ankle 54,
which is defined by
the rider's ankle joint, is disposed forwardly from the rider's knee 48 and
the steering position 36.
These elements, coupled with the placement of steering position 36 behind foot
position 38,
create a situation where rider 26 sits inclined slightly forward, as indicated
in FIG. 1.
The positioning of rider 26 shown in FIG. 1 is considered standard, i.e.., the
standard riding
position. While riders may move our of the standard riding position under
various riding
conditions {e.g., when traversing obstacles, making tight turns, etc.}, the
standard riding position
is used during normal relaxed riding {e.g., long distance riding, touring,
etc.}.
Before the present invention, there was no motivation to adjust 'the position
of rider 26
because the standard position does not hinder operation of the vehicle nor
does it create an unsafe
riding condition for rider 26. Moreover, the conventional positioning of rider
26 on snowmobile
dues not prevent rider 26 from enjoying the sport of snowmobiling.
Despite this, the inventors of the present invention realised that it is
possible to improve
upon the construction of a snowmobile to alter the positioning of the rider to
improve
considerably the handling and ride of the vehicle.
FIGS. 2 and 5 illustrate snowmobile 110, which is made according to the
teachings of the present
invention_
7
CA 02411964 2002-11-15
Like snowmobile 10, snowmobile 110 has a body 112 and a frame 114. Two skis
116 are
positioned at the front of frame 114 so that snowmobile 110 may he steered
over the snow. Skis
116 are connected to frame 114 through a suspensiowsystem 118 attached to
frame 114 at its
forward end. An engine i 1 S is also disposed at the forward end of snowmobile
110 and is
covered by fairings 122 that protect the engine 11 S and provide snowmobile
110 with an
aesthetically pleasing appearance. A windshield 124 may extend upwardly from
fairings 122 to
act as a windscreen for rider 126.
The frame 114 includes a tunnel 119. The tunnel 119 may comprise one ar more
pieces
of bent sheet metal. A drive track 120, which is operatively connected to the
engine 11 S, is
supported below the tunnel 119 via a suspension system. The tunnel 119 is
constructed such that
an upper portion of the drive track l20 fits into a longitudinal channel
formed in the underside of
the tunnel 119.
Drive track 120 is a continuous belt that runs around a number of axles
including a
forward-most axle 121 that is obscured by fairings 122 in FIG. 2. Forward-most
axle 121 of
snowmobile 110 is at or near the center of gravity 144 of snowmobile l I0 with
the rider 126, as
would be understood by those skilled in the art.
When rider 126 is on snowmobile 110, the rider will be positioned on seat 128
so that he
occupies seat position 130. Seat position 130 is the point at which the weight
of the rider 126 is
exerted on the seat 128, and is generally disposed 9 cm below the hips 131 of
the rider 126. Tt
will also be understood that seat 128 will be covered with an amount of foam
or similar padding-
type material, and that the amount flf that foam will vary from seat to seat.
When the rider 126
sits upon the seat 12$, his weight will cause the foam to compress and he will
sink into the seat
128. Preferably, the seating position 130 and hip 131 location is determined
after this
compression has occurred.
Steering device 132 is positioned at the forward end of snowmobile 110 and
above the
engine 115. As is the case with the seating position 130, the steering
position 136 may vary
depending on the size and shape of the hands of the rider 126. In cases of
difficulty, the steering
position 136 may be determined by placing the hands of the standard rider
described above on the
steering device 132 in the standard position. The steering position 136 will
be the intersection of
the center of the palm of the hands of the rider 126 and the steering device
132.
8
CA 02411964 2002-11-15
It should be noted that steering device 13Z is shown as a handlebar hut should
not be
limited to just this particular construction. It would be understood by those
skilled in the art that
any suitable steering device may be used for snowmobile 110. For example,
steering device 132
could be a steering wheel or a yoke of the type used in aircraft. Moreover,
the positioning of
steering device 132 above the engine 115 also should not be considered to be
limited to the
position illustrated in FIG. 2. As would be understood by those skilled in the
art, depending on
the particular arrangement of elements for the snowmobile, it is possible that
steering device 132
could be positioned higher or lower than shown in FIG. 2 without departing
from the scope and
spirit of the present invention.
Footrests 134 are disposed on both sides of the seat 1 Z$ and may be formed
integrally
with or be supported by the tunnel 119 of the frame 114. In the embodiment
illustrated in FIG, 5,
the footrests 134 arc integrally formed with the tunnel 119 such that the
tunnel 119 provides the
structural support for the rider's feet 146. The rider's feet 146 rest on.
footrests 134 in footrest
position 138 just behind the center of gravity 144 of the vehicle 110. The
footrest position 138 is
in the location of the arch of the foot of the rider 126 when his feet are
placed in the standard
position on the vehicle. Under normal operating conditions, the rider's feet
146 will rest on a
forward portion of the sideboards/footrests I34. This foot positioning places
the rider's ankles
13'9, which are defined by the ankle joint, 9 cm above the footrest position
13 8.
As illustarated in FIG. 3, the forward most portion 147 of the footrest 134,
which is
defined by the forward most possible position of the front of the rider's feet
146, is preferably
disposed behind the steering position 136 by a distance G. Distance G is
preferably greater than
0, is more preferably between 5 and 50 cm, is even more preferably between S
and 20 cm, and is
even more preferably about 10 cm.
The rider's ankle 139 and hip 13I positions determine the position of the
rider's knees
141, which are defined by the knee joints. As illustrated in FIGS. 6 and 7,
for the standard rider
126, the distance between the rider's ankles 139 and knees 141 is 41.1 cm.
Similarly, the
distance between the rider's knees 141 and hips 131 is 42.4 em.
As illustrated in FIG. 4, the rider's knees 141 fit into a knee position 142
on the
snowmobile 1 I0. The knee position i42 is defined by a narrowed forward
portion of the seat
128 that is designed to accommodate the rider's knees 141. As illustrated in
FIG. 2, the knee
position lA2 is preferably disposed at the same vertical and longitudinal
position on the
9
CA 02411964 2002-11-15
snowmobile i I O as the rider's knees 141. The open space formed at the knee
position 142
enables the rider 126 to actively position himself and more easily lean into
turns because the knee
position 142 allows the rider's outside knee 141 to move farther into the
turn.
When the standard rider 126 is in the standard position on the snowmobile 110,
the seat
128, footrest 134, and steering device 132 are positioned such that the
rider's hips 131 will be
disposed below the steering position 136 by a vertical distance A, Distance A
is preferably
between 0 and 30 cm., is more preferably between I O and 25 cm, and. is even
more preferably
about 18 cm. Similarly, the rider's hips 131 will be disposed above the
rider's knees 141 by a
vertical distance B. Distance B is preferably between 0 and 20 cm., is more
preferably between 5
and 15 cm, and is even more preferably about 10 cm. The rider's knees 141 will
be disposed
above the rider's ankles 139 by a vertical distance C. Distance C is
preferably between 10 and 40
cm, is more preferably between about 20 and 40 cm, and is even more preferably
about 36 cm.
When the standard rider 126 is in the standard position on the snowmobile 110,
the seat
128, footrest 134, and steering device 132 are positioned such that the
rider's knees 141 will be
disposed at least slightly reanvardly from the steering position 136. A.s
illustrated, the rider's
knees 141 will be disposed behind the steering position 138 by a horizontal
distance D, which is
preferably between 0 and 30 cm, is more preferably between about 0 and 20 cm,
and is even
more preferably about 10 cm. Alternatively, the rider's knees 141 may be
disposed in front of the
steering position 136 such that the distance D is negative (e.g., -5 cm, -10
cm, etc.). The rider's
knees 141 will be disposed forwardly from the rider's ankles 139 by a
horizontal distance E.
Distance E is preferably between 0 and 35 cm, is more preferably between S and
30 cm, is even
more preferably between 15 and 25 cm, and is even more preferably about 18
cra. The rider's
hips 131 will be disposed rearwardly from the rider's ankles 139 by a
horizontal distance F.
Distance F is preferably between 5 and 40 cm, is more preferably between 10
and 30 cm, and is
even more preferably about 22 cm.
The rider's hips 13I axe positioned behind the steering position 136 by a
horizontal
distance that equals distance D plus distance E plus distance F. Distance D+E-
f-F is preferably
less than 70 cm. In an alternative embodiment, distance D+E+F is prefi~rably
between 20 and 80
cm, is more preferably between 30 and 70 cm, is even more preferably between
35 and 60 cm, is
even more preferably between 40 and 60 cm, and is even more preferably about
50 cm. The
resulting hip 131 position preferably places the rider's center of gravity 140
closer to the center
CA 02411964 2002-11-15
of gravity 144 of the snowmobile 110, and thereby centralizes the c;ornbined
mass of the ATV
110 and rider 126. Centralizing the combined mass makes it easier' to turn the
snowmobile 110
because it improves the snowmobile's handling and responsiveness.. This
principle is highlighted
by the fact that it is easier to rotate a 10 kilogram bowling ball than it is
to rotate a 10 kilogram
ladder.
This rider positioning also preferably positions the rider l2ti closer to the
longitudinal
center of the snowmobile 110, which places the rider 126 closer to the
snowmobile's natural
pivot point. Because the rider 126 and the snowmobile 110 will tend to pivot
at similar points,
the rider experiences a more comfortable ride as the snowmobile 110 traverses
uneven terrain or
obstacles. This principle is highlighted by the fact that a person sitting in
the back seat of a bus
experiences more jostling forces than a person sitting toward the middle of
the bus.
The knee position 142 is located at the same position as the knees 141. The
seat position
130 is disposed 9 cm below but generally at the same longitudinal position as
the hips 131. The
ankles 139 are disposed 9 cm above but generally at the same longitudinal
position as the foot
position 138. Accordingly, the relative positions of the steering position
136; seat position 130,
knee position 142, and foot position 138 of the snowmobile 110 caxi be
determined with reference
to the distances A-F.
Hereinafter, several of the advantages of the snowmobile 110 will be described
with
reference to FIGS. 1 and 2.
When rider 26 is sitting on conventional snowmobile 10, ifhe sees a large bump
ahead, it
is natural for rider 26 to try to raise himself off of seat 28 to minimi:ae
the impact of the bump as
he passes over it. However, because of his positioning on conventional
snowmobile 10, in order
for rider 26 to stand up, he must pull on steering device 32 using his upper
body. The positioning
of the rider's feet 46 forurard of the rider's center of gravity 40 and at an
incline on footrests 34
makes it difficult for rider 26 to stand on snowmobile 10 using only the
strength ofhis legs.
Moreover, even after rider 26 lifts himself from seat 28, his center of
gravity 40 remains
sufficiently rearward of the center of gravity of the vehicle 44 that he will
perceive the large
bump.
In snowmobile 110 of the present invention, however, a wholly different result
is
achieved. First, steering position 136 is moved forward relative to tlhe
conventional snowmobile
10. This position pulls rider 126 forward of the conventional position. By
moving seat position
11
CA 02411964 2002-11-15
130 closer to the center of gravity of the vehicle 144 than the conventional
example, redesigning
footrests 134 so that they are kept at a decline, and positioning the zider's
feet 146 horizontally
closer to the rider's center of gravity 140, rider 126 is positioned so that,
if a large bump is seen
in the path ahead, rider 126 can easily raise himself from the seat using
primarily the strength of
only his legs 152. The seat 128, steering device 132, and footrests :134 are
positioned such that
the rider's hips 131, knees 141, and ankles 139 create a positioning that
enables the rider 126 to
easily raise and lower himself to traverse obstacles. The rider's ability to
actively position
himself improves the rider's control over the snowmobile 110. Since rider 126
is disposed closer
to the center of gravity of the vehicle 144, when snowmobile 110 passes over a
large bump, the
effect of the bump is not transferred to rider 126 with the same magnitude as
the force transferred
to rider 26 on conventional snowmobile 10.
In addition, because rider 126 can raise himself from spat 128 using his legs
152 and not
his arms 154, rider 126 can maintain greater control over snowmobile 110 as he
passes over the
obstacle than xider 26 on conventional snowmobile 10. If rider 26 (of
conventional snowmobile
10) tries to pull himself from seat 28 as he passes over a large bump or
obstacle, he sacrifices
some of this strength pulling himself up from seat 28 and, therefore, may be
less able to steer and
control the vehicle 10 as he passes over the obstacle.
The ability ofthe rider 126 to lift himself using his legs 152 also relieves
stress on the
rider's back. When the conventional rider 26 uses his arms to raise himself on
a conventional
snowmobile 10, the rider's lifting force is transferred through his back,
which stresses his back
and fatigues the rider 26. Similarly, the rider 26 uses his back to absorb
movement during
snowmobile operation. Conversely, because the rider 126 of the snowmobile 110
can lift himself
using primarily his legs 152, fewer forces are transferred through the:
rider's back and the rider
126 experiences a more comfortable ride.
To facilitate the rider's ability to raise himself off of seat 128 using his
legs 152, footrests
134 are not inclined as with snowmobile 10. Instead, footrests 134 are part of
the forward
portion ofthe sideboards 135 that laterally extend from the tunnel 119 below
the seat 128 on
either side thereof. As a result, footrests 134 are at angle 4 with respect to
the horizontal.
Prcfcrably, angle ~ is between about +10 and -20°. More preferably,
angle D lies between shout
+10 and -14°. Even more preferably, angle d lies between about 0 and -
5°. Most preferably,
angle b is about -5°.
12
CA 02411964 2002-11-15
As mentioned, one aspect of the present invention that improves upon the
conventional
snowmobile 10 is the fact that the rider's center of gravity 140 is closer to
the center of gravity of
the vehicle 144 than in the conventional example. This positioning helps to
minimize the effect
of bumps and terrain on rider 126. Referring to FIG. 3, it is preferred that a
distance x, measured
as the distance between a vertical line passing through the center of gravity
of the vehicle 144 and
a vertical line passing through the center of gravity of the rider 140, be
between about 0 and 50
cm. It is more preferred that distance x be between about 10 and 4t) cm. In
still a more preferred
example, distance x is between about 22 and 32 cm. In the most preferred
example, distance x is
between about 2S and 30 cm. Similarly, a distance z between a vertical line
passing through the
forward-most drive track axle 121 (usually, but not exclusively the drive
axle) and a vertical line
passing through the center of gravity of the rider 140 is preferably between
about 15 and 65 cm.
More preferably, distance z is between about 25 and 55 cm. Still more
preferably, distance z is
between about 35 and 55 cm. Still more preferably, distance z is between about
37 and 47 cm.
Most preferably, distance z is about 40 cm or about 45 cm.
As discussed above, the steering position 136 of the snowmobile 110 is pushed
forward
relative to the conventional snowmobile 10. To create this steering position
136, the inventors
altered the positioning of the axis of the steering shaft 162 of the steering
device 132 so that it is
mare steeply sloped than the steering shag in prior art snowmobiles having a
steering shaft over
the engine. With a steeper slope to the axis of the steering shaft 162, the
turning force applied by
rider 126 is more directly applied to steer the vehicle 110. According to the
present invention,
and as illustrated in. FIGS. 2 and 3, the axis of the steering shaft 162 forms
an angle s with
vertical that is less than 45°. More preferably, angle c lies between
about 25 and 40°. Even more
preferably, angle s lies between about 30 and 35°. Most preferably,
.angle a is about 33°.
Returning to FIG. 2, positioning rider 126 on snowmobile 11'0 in the manner
described
has still further advantages. Windshield 124 has a top 166. When snowmobile
110 is moving,
top 166 of windshield 124 defines a point from which the air travels along a
travel path 168. The
air along air travel path 168 will have laminar flow characteristics until it
reaches a turbulent flow
region 170. When rider 126 is positioned on snowmobile 110 as described above,
the rider's
head 172 falls within the laminar flow region 174. As a result, rider 1.26
enjoys a more
comfortable ride because the air has a Less adverse effect on his head 172 in
terms of temperature,
noise, etc. This advantageous air flow is achieved, in part, because of the
physical relationship
13
CA 02411964 2002-11-15
between the seat position 130, steering position 136, and top 166.
Specifically, as illustrated in
RIG. 2, a line between the steering position 136 and the seat position 130
forms an angle with a
line between the seat position 130 and the top 166 of the windshield that lies
between about 0 and
20°. More preferably, angle is between about 10 and 20°. Most
preferably, angle is about
18 °. Those skilled in the art will readily recognize that the
resulting positioning of the rider's
head 172 on snowmobile 110 is very different than that for conventional
snowmobile 10, where
the head of rider 26 falls into the turbulent flaw region. Accordingly, rider
26 experiences a
poorer quality ride than rider 126.
The positioning of rider 126 on snowmobile 110 in the xn,anner taught by the
present
invention offers still further advantages. As illustrated, the view that rider
126 has of the ground
in front of him is much improved aver the view of the ground in front of rider
26 on conventional
snowmobile 2fi. This is true because rider 126 has less of the snowmobile
fairings 122 and
windshield 124 in front of him than rider 26 does. As a result, rider I26 is
better able to react to
obstacles in his immediate path than rider 26.
The design of snowmobile 110 offers still further advantages. For example, as
illustrated
in FIG. 1, the rider's knees 48 arc positioned very close to steering position
36. As a result, when
rider 26 steers snowmobile 10, it is not uncommon for rider 2b to hits his
knees 48 with steering
device 32. This presents a minor design difficulty that the present invention
solves. As
illustrated in FIG. 2, the knees 141 of the rider 126 on the snowmobile 110
are disposed below
the steering position 136 by a vertical distance that equals distance A plus
distance B; which is
preferably greater than ZO cm, is more preferably greater than 15 cm, is even
more preferably
greater than 20 cm, and is even more preferably about 28 cm.
As shown in RIG. 4, when rider 126 turns steering device 132; to its maximum
positions,
the handlebars sweep out a handlebar space 176. Because steering device 132 is
positioned
forward of the center of gravity of the vehicle 144, handlebar space 176
cannot intersect with the
space occupied by rider 126. In other words, rider 126 will not normally hit
his knees 141 with
steering device 132 while riding snowmobile 110.
The present invention offers still further advantages over the design of
conventional
snowmobile 10. Since rider 126 is positioned closer to the center of gxavity
of the vehicle 144,
the ride for a second rider on the same vehicle is also improved because the
second occupant is
also disposed closer to the center of gravity of the vehicle. Rider 26 (who is
shown astride
14
CA 02411964 2002-11-15
conventional snowmobile 10) is essentially in the second passenger neat for
snowmobile 110.
Since rider 126 has been moved forward, the second rider is subject to the
kind of forces that he
would be subjected to if he were driving a conventional snowmobile 10. In
other words, the
second rider is na worse off than he would be if he were riderldriver 26 on
conventional
snowmobile 10. Indeed the second rider's situation is quite improved, and may
approach that of
a rider 26 on a conventional snowmobile 10.
1n addition, since second rider experiences a similar ride exp~srience to what
rider 26
experiences on conventional snowmobile, it is possible that a third ni.der
could be added to
snowmobile 110 behind the second rider. The third rider, then, would
experience the forces
similar to those that a second rider would normally experience on conventional
snowmobile 10.
While the invention has been described with reference to several preferred
embodiments,
it will be understood by those skilled in the art that various changes may be
made and equivalents
may be substituted for elements thereof without departing from the spirit and
scope of the present
invention. In addition, many modifications may be made to adapt a particular
situation,
component, or material to the teachings of the present invention without
departing from its
teachings.
1S
