Note: Descriptions are shown in the official language in which they were submitted.
CA 022~1769 1998-11-13
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SNOWMOBILE FRAME ASSEMBLY
BACKGROUND OF THE INVENTION
This invention relates to a snowmobile, and more
particularly, to an improved drive and frame arrangement
for a snowmobile.
Conventionally, snowmobiles have a frame assembly that
supports, at the forward portion thereof, an internal
combustion engine and a transmission that drives a drive
belt positioned beneath the frame assembly and upon which
the frame assembly is supported. A seat is carried by the
frame assembly and generally overlies the drive belt. A
pair of front skis are also carried by the frame assembly
and are dirigibly supported for steering by a rider seated
on the seat.
The drive belt generally is quite wide so as to improve
stability and the transmission of power to the ground so as
to propel the snowmobile. Of course, this means that the
transmission for the drive belt must be disposed at a side
of the drive belt and this driving transmission is driven
from the engine in any of a variety of fashions. The rider,
as is typical with this type of vehicle, is seated on the
seat in straddle fashion and thus must have a place to
position his legs. With the conventional types of drive
constructions previously employed, the rider's legs must be
splayed quite widely if they are to be disposed on opposite
sides of the drive belt and the transmission that drives
it. In order to avoid such uncomfortable seating
positions, it has been the practice to move the seat
rearwardly so that the rider's legs will be disposed behind
the transmission driving the drive belt. This gives rise to
not only a great length for the snowmobile, but also does
not provide the desired balance or handling.
Obviously, the frame assembly must support the engine
and also accommodate the transmission. Conventionally, the
CA 022~1769 1998-11-13
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frame assemblies include a pair of side members and the
rider places his feet on footrests disposed outwardly of
these side members. Because the transmission assembly that
drives the drive belt must be disposed at one side of the
drive belt and outwardly therefor, it has heretofore been
the practice to provide this transmission on the outside of
the frame. This requires the rearward positioning of the
rider and the other problems as aforenoted.
It is an object of this disclosure to describe an
improved frame assembly for a snowmobile that permits a
compact assembly and permits a forwardly positioned rider.
It is a further object to describe an improved frame
assembly for a snowmobile wherein the frame side members
form, at least in part, the transmission case for the drive
belt transmission.
As has been noted, the snowmobile typically employs a
pair of front skis that are steered by a steering mechanism
operated by the rider seated on the seat. This steering
mechanism includes a steering column that is rotatably
supported by the frame assembly and which generally is
inclined upwardly and rearwardly from its forward
connection to the steering skis. As a result of this
disposition of the steering column, it has heretofore been
the practice to position the engine either forwardly and/or
above the steering column. This gives rise to added length
to the snowmobile and also raises the center of gravity,
which is not particularly desirable from a handling
standpoint and from a stability standpoint.
An improved and compact steering arrangement for a
snowmobile is here described.
A steering arrangement for a snowmobile which permits
the engine to be mounted low in the frame and thus maintain
a low center of gravity is also described.
The aforenoted types of steering constructions in which
the steering column passes beneath and to the rear of the
engine also causes the engine and a major portion of the
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transmission to be forwardly located. This tends to add to
the weight on the front skis and reduce the amount of
weight concentrated on the drive belt. As a result,
traction can be decreased with this type of construction.
An improved engine and steering arrangement for a
snowmobile that permits the engine to be located rearwardly
and more over the drive belt than previous types of
construction is also described.
It has already been noted that the drive belt of a
snowmobile is driven by a transmission from the engine. The
drive belt transmission contains a drive belt drive shaft
carrying a number of drive belt driving members that are
engaged with the forward inner portion of the drive belt
for driving it. This shaft obviously rotates about a
transversely extending axis, and it has been the normal
practice in snowmobiles to mount the engine so that its
output shaft also rotates about a transversely extending
axis. This means that with multiple cylinder engines that
the exhaust manifold for the engine will also extend
transversely. As a result, the exhaust system must reroute
the exhaust gases from a transverse direction to a position
wherein the exhaust gases can be discharged to the
atmosphere and generally rearwardly of the engine. In other
words, the exhaust system for the engine also extends the
length of the engine assembly, either in a forward or
rearward direction. This further compromises the location
for the steering column.
An improved steering and engine arrangement for a
snowmobile that permits a compact assembly is here
described.
An exhaust system and steering arrangement for a
snowmobile wherein the steering column may pass between a
portion of the exhaust system and the engine to occupy
otherwise dead space and afford a compact arrangement is
also described.
CA 022~1769 1998-11-13
Attendant to the transverse positioning of the engine
in the snowmobile is also the requirement that the
induction system extend either forwardly or rearwardly from
the engine. This further complicates the layout of
components of the snowmobile and can result in excess
forward weight bias and added length for the snowmobile. As
noted above, both of these features are relatively
undesirable.
An improved compact snowmobile arrangement that
incorporates an induction system that can be interrelated
to other components to afford a compact construction
without unduly affecting the center of gravity is thus here
described.
An improved fuel tank and induction system layout for
the driving power unit of a snowmobile is also described.
A first feature of the apparatus described is embodied
in a snowmobile that is comprised of a frame assembly that
includes a pair of spaced-apart side portions that are
suspended from a drive belt. An internal combustion engine
is disposed at the front of the frame assembly and is
supported with its output shaft extending generally
transversely relative to the frame side portion. A belt
drive shaft is engaged with and drives the drive belt. An
intermediate shaft is driven by the engine output shaft by
first transmission means, and second transmission means
drive the belt drive shaft from the intermediate shaft. The
engine output shaft, belt drive shaft, and intermediate
shaft all rotate about parallel, transversely extending
axes. At least one of the transmission means is positioned
substantially entirely within the lateral confines of the
frame side portion. A seat is carried by the frame means in
proximity to and to the rear of the internal combustion
engine. A pair of foot rests are carried by the frame means
on opposite sides thereof and positioned to accommodate the
feet of a rider seated upon the seat. At least one of the
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feet rests is spaced transversely outwardly of the one
transmission means.
Another feature of the apparatus is embodied in a frame
assembly for a snowmobile that is comprised of a first
section comprised of a pair of side portions and a top
portion having a generally inverted U-shaped cross section
adapted to overlie a drive belt. A pair of side members are
affixed at the forward ends of the side portions and extend
forwardly therefrom for defining a cradle adapted to
receive an internal combustion engine for powering the
snowmobile. At least one cross member is affixed to and
spans the side members.
Still additional features are embodied in a snowmobile
that is comprised of frame means, a drive belt suspended by
the frame means, and an engine supported by the frame
means. Transmission means drive the drive belt from the
engine. A seat is carried by the frame means behind the
engine and above the drive belt. A pair of dirigible front
skis is carried by the frame means.
In accordance with one of these additional features,
steering means are carried by the frame means forwardly of
the seat for operation by an operator seated upon the seat
for steering of the front skis. The steering means includes
a steering shaft that is rotatable about an axis that is
upwardly inclined in a rearward direction and that passes
over the engine.
In accordance with another of these additional
features, the engine has exhaust port means on one side of
the engine and an exhaust system is provided for
discharging exhaust gases from the exhaust port means to
the atmosphere. This exhaust system includes a manifold
having a first portion extending away from the one side of
the engine, a second portion extending along one end of the
engine, and connected to the first portion by a re-entrant
portion to define a generally U-shape in top plan view.
Steering means are carried by the frame means forwardly of
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the seat for operation by an operator seated upon the seat
for steering of the front skis. The steering means includes
a steering shaft rotatable about an axis that extends
between the one side of the engine and the re-entrant
portion of the exhaust manifold.
In accordance with an additional feature, the engine is
formed with intake port means on one side thereof, and an
induction system is affixed to this one side of the engine
for delivering at least an air charge to the intake port
means. This induction system includes an air inlet device
for drawing atmospheric air. A fuel tank is carried by the
frame means for supplying fuel to the engine for its
operation. This fuel tank has a generally L-shaped
configuration in top plan view and is comprised of a first
long-leg section that extends along one side of the engine
contiguous to the air inlet device and a second short leg
extending from one end of the first long leg towards the
one side of the engine and along and offset to one side of
the induction system and the air inlet device.
More particularly in accordance with the invention
there is provided, a frame assembly for a snowmobile
comprised of a first member comprised of a pair of side
portions and a top portion having a generally inverted U-
shaped cross section adapted to overlie a drive belt, a
pair of front side plates affixed to the forward ends of
said side portions and extending forwardly therefrom for
defining a cradle adapted to receive an internal combustion
engine for powering the snowmobile and at least one cross
member affixed to and spanning said front side plates.
Embodiments of the invention will now be described with
reference to the accompanying drawings wherein;
Figure 1 is a side elevational view of a snowmobile,
with the body assembly shown in phantom and with portions
of the frame assembly shown in phantom so as to more
clearly show the construction. In addition, certain
portions are broken away.
CA 022~1769 1998-11-13
Figure 2 is a top plan view of the snowmobile with the
same portions shown in phantom so as to more clearly show
the relationship of the steering engine and transmission
arrangement.
Figure 3 is an enlarged front elevational view of the
snowmobile with portions broken away and shown in section,
illustrating the same components as shown in solid lines in
other figures.
Figure 4 is an enlarged side elevational view of the
forward portion of the snowmobile with additional portions
shown in cross section and the transmission removed so as
to more clearly show the arrangement for mounting the
engine and body.
Figure 5 is an enlarged cross-sectional view showing a
portion of the transmission mechanism, which is also shown
in Figure 3.
Figure 6 is an enlarged top plan perspective view of
the frame assembly with a portion broken away.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE
INVENTION
A novel snowmobile is shown in the drawings and is
identified generally by the reference numeral 11. The
snowmobile 11 is comprised of a number of main components,
including a frame assembly, indicated generally by the
reference numeral 12, and which is shown in part in phantom
in some of the figures. The frame assembly 12 is suspended
on a drive belt 13 by means of a carriage assembly 14. A
seat 15 is supported on the frame assembly 12 over the
drive belt 13 and carriage assembly 14 and is sized to
accommodate a single rider seated in straddle fashion, as
is typical in snowmobile practice, with the rider being
shown in some of the figures and identified by the
reference numeral 16.
CA 022~1769 1998-11-13
An internal combustion engine, indicated generally by
the reference numeral 17, is carried by the frame 12
forwardly of the seat 15 in a manner that will be described.
The engine 17 drives an intermediate shaft 18 by means of a
first transmission, indicated generally by the reference
numeral 19, and which is of the variable ratio type and which
also includes a centrifugal clutch. The intermediate shaft
18, in turn, drives the drive belt 13 by a second
transmission 21, which will also be described later in more
detail.
A pair of front skis 22 are supported by a suspension
system at the front of the frame assembly 12 and are
dirigible for steering of the snowmobile 11. A handlebar
assembly 23 is supported forwardly of the rider's seat 15 for
steering of the skis 22 in a manner that will be described.
A fiberglass reinforced resinous plastic body 24 is
mounted on the frame assembly 12 and has a windshield 25 that
is disposed forwardly of the handlebar 23 for protection of
the rider 16.
The frame assembly 12 will be now described in more
detail by particular reference to Figure 6. The frame
assembly 12 is made up of a fabrication of a number of pieces
of aluminum for light weight, although it is to be understood
that other materials may be employed or certain portions of
the frame assembly may be formed from other materials. Also,
the manner of fabrication that is described is only typical,
and other methods may be employed for forming the individual
components of the frame assembly 12 or its sub-components.
The frame assembly 12 is comprised of a rear portion,
indicated generally by the reference numeral 26, and which
has a generally inverted U shape with a flat section 27 that
tapers generally downwardly in a rearward direction and a
pair of side pieces 28. The lower ends of the side pieces 28
are formed with outwardly extending flanges 29 that have
CA 022~1769 1998-11-13
their rigidity improved by forming rolled portions 31 at the
outer periphery thereof. It should be noted that the side
portions 28 ha~e a generally triangular configuration in side
elevation, while the cross-sectional shape of the frame
s portion 26 has an inverted U shape, with the outward legs 29
extending outwardly from the lower ends thereof.
A pair of side plates 32 and 33, which may be formed as
stampings, forgings, or the like and which have a generally
C-shaped opening at the front end thereof, are affixed in a
suitable manner to the front portion of the rear frame member
26. The side plates 32 and 33 may be formed with flanges 34
that o~erlie the upper surface 26 and lower flanges 35 that
overlie the flanges 29 of the frame member 26 so as to add
rigidity to the construction. These side members 32 and 33
may be fixed to the frame member 26 by riveting, welding, or
the like.
A pair of rectangularly shaped cross members 36 and 37
are af~ixed between the side plates 32 and 33 and add to
their rigidity. These cross members 36 and 37 may be formed
as extrusions or the like, also from aluminum alloy. The
frame assembly further includes a support plate 38 that
extends from the front of the frame member 26 between the
side plates 32 and 33 and forwardly to the cross member 37 so
as to form a cradle-like configuration in which the engine 17
is mounted in a manner that will be described. The side
plate 33 is also formed with a side opening 39 so as to form
a case for the transmission 21, as will also be described.
Referring now primarily to Figures 1-4, the engine 17
is, in the illustrated embodiment of the two-cylinder in-line
type, which operates on a two-stroke crankcase compression
principle. As is typical with snowmobile practice, the
engine 17 is mounted in the frame assembly 12 so that its
crankshaft 41 rotates about a transversely extending axis.
The engine 17 is mounted within the frame assembly 12 so as
to be offset to one side of the frame assembly 12,
specifically toward the
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CA 022~1769 1998-11-13
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left-hand side in the illustrated embodiment. Although the
invention is described in conjunction with a two-cylinder
engine operating on a two-stroke crankcase compression
principle, it will be obvious to those skilled in the art
s that certain facets of the invention may be employed with
engines of other types. However, the offsetting of the
engine 17 to one side of the frame assembly 12 permits the
placement of the transmissions for driving the drive belt 13
in the manner to be described.
The engine 17 is also disposed so that its exhaust ports
face forwardly, and these exhaust ports deliver the exhaust
gases to an exhaust system, indicated generally by the
reference numeral 42. This exhaust system includes a
manifold 43 having a Y-shaped inlet end that extends to a
forwardly extending collector portion 44. This forwardly
extending collector portion is disposed axially forwardly of
the frame assembly 12, for a purpose to be described, and
then merges into a re-entrant or U-shaped section 45. The
opposite end of the U-shaped section 45 is connected to an
integral expansion chamber 46 that extends along one end of
the engine on the right-hand side of the frame assembly 12.
The exhaust gases are then introduced to a muffler 47 for
silencing and discharge to the atmosphere. It should be
noted that the muffler 47 is in essence placed at one side or
end of the engine, considering its transverse disposition,
and thus this permits a very compact assembly and maximum
space utilization without interfering with the serviceability
of the components.
An electrical generator, indicated generally by the
reference numeral 48, is driven off of the right-hand side of
the engine and is interposed between the engine 17 and a
recoil starter 49. Again, this construction permits a
compact assembly and yet full serviceability of the
components.
The engine 17 is provided with an induction system that
extends to the intake ports of the engine but rearwardly of
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the exhaust system 42. This induction system is indicated
generally by the reference numeral 51 and includes an air
inlet device 52 that draws atmospheric air from an area
within the body 24 and forwardly of the legs of the rider 16.
This air inlet device 52 may include a silencing arrangement
and also an air filter element, which will be readily
serviceable because of its positioning forwardly of the seat
16. The thus filtered and silenced air is then delivered by
a pair of air supply conduits 53 to a pair of carburetors 54,
one for each cylinder of the engine. The carburetors 54 form
a fuel/air mixture and discharge this to the intake parts
into crankcase chambers of the engine through an intake
manifold 55.
Since the engine 17 is offset to the left side of the
frame assembly 12, the induction system 51 is also so offset.
This permits the use of an L-shaped fuel tank, indicated
generally by the reference numeral 56, which is carried by
the frame assembly 12 forwardly of and beneath the seat 15.
This fuel tank 56 has a generally L-shaped configuration in
top plan view and is comprised of a transversely extending
portion 57 that extends across the rear surface of the air
inlet device 52 and beyond it to a short leg 58 that extends
forwardly along the side of the air inlet device 52. Again,
this provides a compact, and yet very serviceable, layout for
the components of the snowmobile.
The engine 17 is mounted within the cradle formed by the
front side members 32 and 33 by elastomeric vibration
isolators 58, which are, in turn, connected to front and rear
sub-frame assemblies 59 and 61, which are affixed suitably to
the panel 38 of the front frame assembly. Thus, the engine
17 is well supported and yet is easily serviceable.
The engine 17 is water cooled and is provided with a
cooling jacket and coolant pump, as is well known in this
art. There is provided a radiator, indicated generally by
the reference numeral 62, which is mounted on the underside
of the plate 38 and forwardly of the drive belt 13 SO that
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CA 022~1769 1998-11-13
.
the drive belt 13 will, in fact, operate as a fan so as to
circulate air over the radiator 62 to improve the heat
exchange. The radiator 62 actually has a generally angular
configuration comprised of a rearwardly inclined, upwardly
s extending section 63 and a horizontally extending section 64
so as to increase the effective area of the radiator while
still maintaining a compact assembly. The tubes of the
radiator 62 extend transversely, and the radiator is provided
with fins that extend generally longitudinally so as to
improve the cooling. In addition, some snow may be thrown
onto the radiator 62 by the drive belt 13, and this will
further heat exchange from the coolant and further improve
the cooling of the engine.
The drive arrangement for driving the drive belt 13 from
the engine crankshaft 41, including the transmissions 19 and
21, will now be described by particular reference to Figures
1-3 and 5. Referring first to Figures 1-3, wherein the first
transmission 19, which is disposed at the left-hand side of
the frame assembly 12, is illustrated. This transmission 19
is of the variable speed type and includes a variable pulley
65, which is driven from the crankshaft 41 through a
centrifugal clutch (not shown), which can be conveniently
positioned within the hub of the variable pulley 65. This
variable pulley 65 drives a drive belt 66, which, in turn, is
entrained on a fixed pulley 67 that is fixed to the left-hand
side of the intermediate shaft 18.
This intermediate shaft 18 is journalled at the left-
hand side of the frame assembly 12 in the side plate 32 by a
suitable bearing supported thereby. It should be noted that
the axis of the intermediate shaft 18 is disposed above and
slightly to the rear of the crankshaft 41, as best seen in
Figures 1 and 2. This positioning permits the fixed pulley
67 to be disposed forwardly of the rider's legs and in an
area where it will not encroach upon them or their foot area.
This permits a relatively narrow overall construction for the
snowmobile and also permits the engine 17 to be shifted
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CA 022~1769 1998-11-13
.
rearwardly in the frame assembly 12 closer to the forward end
of the drive belt 13 so as to increase the amount of weight
carried by the drive belt 13 and, accordingly, the driving
traction.
The intermediate shaft 18 extends across the frame
assembly 12 and is parallel to the crankshaft axis 41 and
then passes through the opening 39 afore-referred to in the
frame side plate 33. A transmission case comprised of a main
case member 68 and a cover plate 69 is affixed to the side
frame plate 33 and forms an enclosure for the transmission
21. A pair of anti-friction bearings 71 and 72 are carried
by the main case member 68 and cover plate 69, respectively,
so as to journal the intermediate shaft 18 in the slde frame
plate 32.
A driving sprocket 73 is formed on the intermediate
shaft 18 within the case formed by the member 68 and the
cover plate 69, and drives a drive chain 74, which is
positioned laterally within the frame side plate 33. This
inward placement of the transmission 21 permits the
positioning of a pair of foot rests 75 on opposite sides of
the frame 12 as somewhat forward extension of the frame
member portions 29 that extend forwardly and upwardly so as
to permit the rider to place his feet at a convenient
position that is not significantly outward of the seat 15,
and thus does not require a splayed leg position for the
rider. This is true, even though the chain 74 extends
between the rider's legs and adjacent his right leg, as
clearly seen in the drawings. This also permits the seat 15
to be disposed forwardly from the prior art constructions,
and thus permits the rider 16 to be able to have the bulk of
his weight directly over the drive belt 13 so as to improve
traction.
A brake disk 76 is affixed to the outer end of the
intermediate shaft, and a disk brake caliper (not shown) is
- mounted on the frame assembly in a suitable manner for
CA 022~1769 1998-11-13
braking the rotation of the brake disk 76, intermediate shaft
18, and snowmobile in a well-known manner.
The chain 74 is trained at its lower end around a
sprocket 77 that is affixed to a belt drive shaft 78. The
s belt drive shaft 78 is journalled in the cover housing 68 on
an anti-friction bearing 79. The opposite end of the belt
drive shaft 78 is also appropriately journalled within the
frame side plate 32 by a suitable bearing. The belt drive
shaft 78 has affixed to it a plurality of belt drive wheels
81, only one of which appears in the figures, and which is
engaged with suitable lugs formed on the interior of the
drive belt 13 for driving it in a manner well known in this
art.
The carriage assembly 14 that suspends the drive belt 13
is comprised of a pair of guide rails 82 that journal a
plurality of idler rollers 83 for defining the path of the
drive belt 13. A pair of links 84 and 85 are connected to
the frame assembly at their upper ends and suspend the guide
rails 82 and drive belt I3 for suspension movement relative
to the frame assembly 12 in any known manner. Tubular shock
absorbers and coil compression springs 86 and 87 are loaded
between the frame assembly 12 and the guide rails 82 for
cushioning and dampening the suspension movement of the drive
belt 13 in a manner well known in this art.
The system for dirigibly suspending the front skis 22
will now be described by particular reference to Figures 1-4,
and this includes a rod-like member 89 that has a pivotal
connection 91 to the respective ski 22, which permits
movement of the ski to a limited extent about the pivot pin
91. The pin 89 is journalled for rotation about a steering
axis within a cylindrical member 92. The cylindrical member
92 is affixed, as by welding, to a bracket 94, which bracket
in turn has a pair of pivotal connections 95 and 96 to one
end of respective suspension links 97 and 98. The opposite
ends of the suspension links 97 and 98 are pivotally
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CA 022~1769 1998-11-13
connected to a suspension bracket 99 that is affixed as by
welding to the front of the frame cross member 37.
A pair of combined shock absorbers spring assemblies 101
are loaded between suspension brackets 102 affixed to the
forward end of the frame side plates 32 and 33 and a pivot
connection 103 on the ski brackets 94 so as to dampen the
suspension movement of the skis 22 relative to the frame
assembly 12.
As has been noted the handlebar assembly 23 is employed
for steering the skis 22. To permit this, the handlebar
assembly 23 is connected to the upper end of a steering shaft
104 that is disposed at approximately a 45 degree angle to
the horizontal and vertical and which extends upwardly from
a lower end through the bight formed by the re-entrant
portion 45 of the exhaust system 42 for the engine 17 and
over the top of the engine 17. In this way, the steering
shaft 104 can be conveniently placed in an otherwise void
area and will not interfere with any other components. This
provides not only a compact assembly but also permits the
engine 17 to be mounted low in the frame 12 so as to lower
the center of the gravity of the snowmobile 11 as well as
permitting the engine 17 to be moved rearwardly so as to
improve the center of gravity in a fore and aft direction and
to place the bulk of the weight on the drive belt 13 while
still maintaining sufficient weight on the front skis 22 for
steering purposes.
The steering shaft 104 is journalled at its upper end on
by a bearing block 105 that is affixed to the cross member 36
of the frame assembly 12. The lower end of the steering
shaft 104 is journalled in a lower bearing block 106 that is
affixed to the cross member 37 of the frame assembly 12. The
lower end of the steering shaft 104 has affixed to it a
steering arm 107 that has a pivotal connection to a pair of
drag links 108 at one end of these drag links. The opposite
ends of the drag links 108 are connected to a respective
steering arm 109 by a pivotal connection so that rotation of
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the steering shaft 104 will affect rotation of the steering
arms 109. These steering arms 109 are, in turn, affixed to
the upper ends of the ski support pins 89 so as to rotate
them in their cylindrical supports 92 and steer the front
skis.
In order to provide further reinforcing for the frame
assembly, there are provided a pair of removable cross braces
110 that are affixed by threaded connections at their upper
ends to the forwardly extending portions of the side plated
32 and 33 and at their lower ends in the same manner to the
lower end extensions of the side plates 32 and 33 of the
frame assembly 12. These cross braces can be removed for
servicing and yet add great rigidity to the overall frame
construction.
If desired, the snowmobile 11 may be provided with a
speedometer or the like which has a drive associated with the
drive belt shaft 78 and which is indicated by the reference
numeral 112 in Figure S.
It should be readily apparent from the foregoing
description that the described snowmobile construction
provides an extremely compact assembly and also is very
effective in maintaining the center of gravity of the
snowmobile very low and also generally over the drive belt 13
so as to improve its traction. In addition, the construction
permits the rider's seat to be moved forwardly and permits a
reduction in the overall length of the snowmobile without
adversely affecting the rider's seating position nor
requiring him to splay his legs apart to any significant
extent. Of course, the foregoing description is that of a
preferred embodiment of the invention and various changes and
modifications may be made without departing from the spirit
and scope of the invention, as defined by the appended
claims.
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