U.S. patent application number 10/061184 was filed with the patent office on 2002-08-08 for snowmobile ski.
Invention is credited to Lemieux, Rene.
Application Number | 20020105166 10/061184 |
Document ID | / |
Family ID | 26740811 |
Filed Date | 2002-08-08 |
United States Patent
Application |
20020105166 |
Kind Code |
A1 |
Lemieux, Rene |
August 8, 2002 |
Snowmobile ski
Abstract
A snowmobile ski includes a bridge portion adapted to connect to
a ski leg of a snowmobile, a ski body having a top surface adapted
to be connected to the bridge and a bottom surface adapted for
moving over snow, the bottom surface having a front portion, a
middle portion and a rear portion, a single keel running lengthwise
exclusively along the middle portion and the rear portion of bottom
surface of the ski body, and a runner provided on the keel.
Inventors: |
Lemieux, Rene; (Granby,
CA) |
Correspondence
Address: |
PILLSBURY WINTHROP, LLP
P.O. BOX 10500
MCLEAN
VA
22102
US
|
Family ID: |
26740811 |
Appl. No.: |
10/061184 |
Filed: |
February 4, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60265632 |
Feb 2, 2001 |
|
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Current U.S.
Class: |
280/609 ;
280/602 |
Current CPC
Class: |
B62B 17/02 20130101 |
Class at
Publication: |
280/609 ;
280/602 |
International
Class: |
A63C 005/04 |
Claims
I claim:
1. A snowmobile ski, comprising: a bridge adapted to connect to a
ski leg of a snowmobile; a ski body having a top surface adapted to
be connected to the bridge and a bottom surface adapted for moving
over snow, the bottom surface having a front portion, a middle
portion and a rear portion; and a single keel running lengthwise
exclusively along the middle portion and the rear portion of the
bottom surface of the ski body.
2. The snowmobile ski of claim 1, further comprising a runner
provided on the keel.
3. The snowmobile ski of claim 1, wherein at least a portion of the
bottom surface of the front portion has a convex cross-section.
4. The snowmobile ski of claim 2, wherein the runner runs
lengthwise exclusively along the middle portion and the rear
portion of the bottom surface of the ski body.
5. A snowmobile ski, comprising: a ski body having a top surface
for connecting to a snowmobile and a bottom surface adapted for
moving over snow, the bottom surface extending longitudinally along
a front portion, a middle portion and a rear portion, wherein the
bottom surface of the front portion includes a convex protrusion
extending longitudinally along the bottom surface from the front
portion toward the rear portion of the ski.
6. The snowmobile ski of claim 5, further comprising: a single keel
running lengthwise exclusively along the middle portion and the
rear portion of bottom surface of the ski body; and a runner
provided on the keel running lengthwise exclusively along the
middle portion and the rear portion of the bottom surface of the
ski body, wherein the convex protrusion meshes with the single keel
along the middle portion of the ski body.
7. A snowmobile ski, comprising: a bridge adapted to connect to a
ski leg of a snowmobile; a ski body having a top surface adapted to
be connected to the bridge and a bottom surface adapted for moving
over snow, the bottom surface having a front portion, a middle
portion and a rear portion; and a single keel running lengthwise
along the middle portion and the rear portion of bottom surface of
the ski body, wherein the front portion of the bottom surface has a
smooth curve protrusion that blends into the keel.
8. The snowmobile ski of claim 7, further comprising a runner
provided on the keel running lengthwise exclusively along the
middle portion and the rear portion of the bottom surface of the
ski body.
9. A snowmobile ski, comprising: a bridge adapted to connect to a
ski leg of a snowmobile; a ski body having a top surface adapted to
be connected to the bridge and a bottom surface adapted for moving
over snow, the bottom surface having a front portion, a middle
portion and a rear portion; and a keel running lengthwise
exclusively along the middle portion and the rear portion of the
bottom surface of the ski body, wherein a longitudinally extending
centerline of the keel is substantially aligned with a
longitudinally extending centerline of the ski body.
10. The snowmobile ski of claim 8, further comprising a runner
provided on the keel.
Description
[0001] This application claims the benefit of U.S. application Ser.
No. 60/265,632, filed Feb. 2, 2001, which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a snowmobile ski, and
particularly, a snowmobile ski having a substantially convex front
portion.
[0004] 2. Description of Related Art
[0005] In designing snowmobile skis, there are several performance
criteria that are deemed to be important. These include, inter
alia, maneuverability, steerability, stability, flotation, and
side-hilling capability. "Maneuverability" is also referred to as
"aggressivity" in the industry and describes the ability of the
skis to provide an effective and superior handling/steering of the
snowmobile in response to the turning of the steering bar of the
snowmobile. "Steerability" refers to the relative ease with which
the snowmobile can be steered with the skis. By definition, a set
of skis is easy to steer when the resistance to the steering is
kept minimal. "Stability" addresses the pitching and darting
tendency of the snowmobile skis during the ride. Rather than being
aligned stably in the intended direction without much wavering,
snowmobile skis may pitch and dart, thereby requiring frequent
adjustments in steering to steer the skis and the snowmobile in the
intended driving direction. "Floatation" refers to the performance
of the skis on snow (as opposed to trails or ice) which allows the
snowmobile to be propelled over snow. In such applications as
mountain snowmobiles, a superior floatation characteristic is
essential as the snowmobile will often be driven on deep fresh
powder snow. Finally, "side-hilling capability" refers to the
performance of the snowmobile skis, typically on mountain
snowmobiles, when the snowmobile climbs a hill by traversing
diagonally up the hill in a zig-zag fashion. In side-hilling, the
snowmobile is tilted alternately in the direction of the turn, and
as a result, the ski on the tilted side tends to be relied upon
more heavily than the ski on the other side during each turn. In
instances where the skis have poor side-hilling capabilities, the
snowmobile may slip laterally because not enough snow is engaged by
the skis when tilted on one side.
[0006] Depending on the intended application of the snowmobiles,
the particularities of the designs of the snowmobile skis or the
methods of attaching the skis to the snowmobile can be varied so as
to optimize the desired performance characteristics of the skis.
For example, the skis for snowmobiles designed for primarily trail
applications, such as a touring type snowmobile, should have
superior performance characteristics in stability, steering and
aggressivity, whereas there is a high premium placed on floatation
and side-hilling for skis designed for mountain snowmobiles.
Indeed, prior patents illustrate numerous examples of attempts to
improve the desired characteristics of the snowmobile skis.
[0007] For example, U.S. Pat. No. 5,038,882 shows a conventional
snowmobile ski which comprises a ski liner adapted to be connected
to a bridge on its top surface, a keel disposed longitudinally
along the bottom snow-contacting surface of the ski liner, and a
runner (also referred to as a "wear rod") disposed on the keel. The
bridge connected to the ski liner's top surface is adapted to
connect to the ski leg of the snowmobile. The ski shown in the '882
patent is typical of conventional skis in that the keel extends
longitudinally along the middle of the ski bottom surface. Notably,
the keel extends from the very front of the ski bottom surface all
the way to the rear end of the ski bottom surface. The '882 patent
states that a more comfortable ride can be obtained by a spindle
arrangement which offsets its longitudinal axis from the ball
joints connected to each spindle. Such an offset spindle
arrangement, according to the '822 patent, induces the ski to
"toe-out" thereby providing improved stability, i.e., less pitching
and darting.
[0008] In other examples, U.S. Pat. Nos. 5,040,818 and 5,145,201
disclose a snowmobile ski having a plurality of concave surfaces
extending along the snow contacting bottom surface of the ski. The
ski shown in these two patents has a center concave surface
extending along the middle of the ski and two concave steering
surfaces which are recessed from the center concave surface that is
equivalent to the keel of the ski. The '818 and '201 patents state
that the plurality of concave portions provides floatation by
compacting snow and lifting the ski and that the lateral recessed
steering portions provide better stability and control as the ski
turns. Much like the ski shown in the '822 patent, however, the
center concave surface, or the keel, of the ski shown in the '818
and '201 patents longitudinally extends along the middle of the ski
from the front end to rear end of the bottom surface. Stated
another way, the keel runs longitudinally about the entire length
of the bottom surface.
[0009] While snowmobile skis disclosed in the aforementioned
patents have keels and runners longitudinally extending along the
middle of the skis, several other prior patents disclose snowmobile
skis with the keels or runners at the lateral sides of the skis,
thereby forming a tunnel or channel--offering a different kind of
snowmobile ski with its own set of advantages and disadvantages.
For example, U.S. Pat. Nos. 3,734,221 and 3,817,544 disclose a
snowmobile ski having a longitudinally extending central groove
that creates a concave shape. The runners are provided on both
sides of the groove, and the central groove is said to provide
improved steerability. Finally, U.S. Pat. No. 5,836,594 discloses a
double-keel snowmobile ski having the keels extending down from the
two lateral edges of a flat middle portion of the ski liner,
wherein vertically and horizontally extending wedges are provided
at the longitudinal ends of each of the keels and a concave front
portion of the ski liner is provided to funnel the snow to the
middle portion of the ski liner. In particular, the ski disclosed
in the '594 patent has double lateral keels disposed in the middle
portion of the ski only to reduce resistance to yawing, which is
defined in the '594 patent as lateral turning of the ski. According
to the '594 patent, a snowmobile ski with the double-keel
arrangement disclosed therein enhances floatation, efficient
turning, and smooth forward and reverse movement. While skis with
tunnel shaped bottom surfaces tout the respective improvements in
various performance criteria, these skis are structurally more
complex than the conventional skis with a single keel extending
longitudinally in the middle of the bottom surface of the ski.
[0010] These and other prior art snowmobile skis heretofore
available, however, do not teach or suggest a snowmobile ski having
a substantially smooth convex front bottom surface and a keel that
extends longitudinally and substantially along the middle of the
ski. Snowmobiles skis having these features in accordance with the
present invention provide improved stability and steerability
characteristics without sacrificing aggressivity.
SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to provide a
snowmobile ski with improved performance characteristics. According
to an aspect of the present invention, a snowmobile ski is provided
with a bridge adapted to connect to a ski leg of a snowmobile; a
ski body having a top surface adapted to be connected to the bridge
and a bottom surface adapted for moving over snow, the bottom
surface having a front portion, a middle portion and a rear
portion; a single keel running lengthwise exclusively along the
middle portion and the rear portion of bottom surface of the ski
body; and a runner provided on the keel.
[0012] In accordance with another aspect of the present invention,
a snowmobile ski is provided with a bridge adapted to connect to a
ski leg of a snowmobile; a ski body having a top surface adapted to
be connected to the bridge and a bottom surface adapted for moving
over snow, the bottom surface having a front portion, a middle
portion and a rear portion; a keel running lengthwise exclusively
along the middle portion and the rear portion of bottom surface of
the ski body and in such a manner that a longitudinally extending
centerline of the keel is substantially aligned with a
longitudinally extending centerline of the ski body; and a runner
provided on the keel.
[0013] It is yet another aspect of the present invention to provide
a snowmobile ski that comprises a bridge adapted to connect to a
ski leg of a snowmobile; a ski body having a top surface adapted to
be connected to the bridge and a bottom surface adapted for moving
over snow, the bottom surface having a front portion, a middle
portion and a rear portion; a keel running lengthwise exclusively
along the middle portion and the rear portion of bottom surface of
the ski body and in such a manner that a longitudinally extending
centerline of the keel is substantially aligned with a
longitudinally extending centerline of the ski body; and a runner
provided on the keel, wherein the front portion of the bottom
surface of the ski boy has a substantially convex shape.
[0014] Still it is yet another aspect of the present invention to
provide a snowmobile ski comprising a bridge adapted to connect to
a ski leg of a snowmobile; a ski body having a top surface adapted
to be connected to the bridge and a bottom surface adapted for
moving over snow, the bottom surface having a front portion, a
middle portion and a rear portion; a single keel running lengthwise
along the middle portion and the rear portion of bottom surface of
the ski body; and a runner provided on the keel, wherein the front
portion of the bottom surface has a smooth curve protrusion that
blends into the keel.
[0015] Other objects and advantages of the present invention will
be apparent from the appended claims and understood from the
following detailed description of the present invention and the
following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Reference will be made hereinafter to the accompanying
drawings which illustrate embodiments of the present invention
discussed herein below, wherein:
[0017] FIG. 1(A) is a side view of a snowmobile ski in the prior
art;
[0018] FIG. 1(B) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1B-1B;
[0019] FIG. 1(C) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1C-1C;
[0020] FIG. 1(D) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1D-1D;
[0021] FIG. 1(E) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1E-1E;
[0022] FIG. 1(F) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1F-1F;
[0023] FIG. 1(G) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1G-1G;
[0024] FIG. 1(H) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1H-1H;
[0025] FIG. 1(I) is a sectional view of the snowmobile ski shown in
FIG. 1A taken along line 1I-1I;
[0026] FIG. 2(A) is a side view of a snowmobile ski in accordance
with the first embodiment of the present invention;
[0027] FIG. 2(B) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2B-2B;
[0028] FIG. 2(C) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2C-2C;
[0029] FIG. 2(D) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2D-2D;
[0030] FIG. 2(B) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2B-2E;
[0031] FIG. 2(F) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2F-2F;
[0032] FIG. 2(G) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2G-2G;
[0033] FIG. 2(H) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2H-2H;
[0034] FIG. 2(I) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2I-2I;
[0035] FIG. 2(J) is a sectional view of the snowmobile ski shown in
FIG. 2A taken along line 2J-2J;
[0036] FIG. 3 is a side view of a snowmobile ski in accordance with
the second embodiment of the present invention;
[0037] FIG. 4(A) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4A-4A;
[0038] FIG. 4(B) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4B-4B;
[0039] FIG. 4(C) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4C-4C;
[0040] FIG. 4(D) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4D-4D;
[0041] FIG. 4(E) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4E-4E;
[0042] FIG. 4(F) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4F-4F;
[0043] FIG. 4(G) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4G-4G;
[0044] FIG. 4(H) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4H-4H;
[0045] FIG. 4(I) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4I-4I;
[0046] FIG. 4(J) is a sectional view of the snowmobile ski shown in
FIG. 3 taken along line 4J-4J;
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0047] A conventional snowmobile ski is shown in FIGS. 1(A)-1(I).
As can be seen in FIGS. 1(A)-1(I), the conventional snowmobile ski
110 comprises a ski body 112 (also referred to in the art as a ski
liner) having a top surface 114 that has a bridge portion 116 that
is adapted to be connected to a ski leg of a snowmobile. The bridge
portion 116 on the top surface of 114 of the ski body 112 may be
integrally formed with the ski body 112 or may have a discrete
bridge assembly unit (typically metal or aluminum) and a
corresponding bridge mating portion on the top surface 114 of the
ski body 112 via nuts and bolts connection. The ski body has a
front end 118 and a rear end 119. The front end 118 of the ski body
112 may be adapted to connect to a plastic handle (not shown).
[0048] The ski body 110 further comprises a bottom surface 120 that
is adapted for moving over snow or trail in response to the
propulsion provided by ground engaging track (not shown). For ease
of describing the present invention and conventional snowmobile
skis related to the present invention the ski body will be
described as having a front portion, a middle portion and a rear
portion. In FIG. 1(A), the bottom surface 120 of the ski body 112
has a front portion 122 that is upturned so that the ski will move
smoothly over the snow or trail; a middle portion 124 that is
substantially a flat surface; and a rear portion 126 that is also
upturned, much like the front portion 122 except to a lesser
degree.
[0049] As can be seen in FIGS. 1(C)-1(I), a keel 130 is provided on
the bottom surface 120 of the ski body 112 and extends
longitudinally along the middle of the bottom surface 120 of the
ski body 112. The keel 130 is a protrusion extending downwardly
from the bottom surface 120 of the ski body 112 and typically has a
trapezoidal cross-sectional shape. A wear rod, such as a metal
guide rod or carbide runner, is placed on the bottom surface of the
keel 130. For example, FIGS. 1(E) and 1(H) show indentations 134 on
the bottom surface 132 of the keel 130 that is adapted to receive a
runner (not shown).
[0050] In conventional snowmobile skis, such as one shown in FIGS.
1(A)-1(I), the ski body 112 typically has a flat horizontal cross
section from one lateral end of the ski body 112 to the other later
end except for the downwardly protruding keel 130, as illustrated
in FIGS. 1(B)-1(I). While these prior art skis have an acceptable
degree of stability (i.e., sufficiently less incidents of pitching
and darting) and aggressivity in response to the steering, these
skis can be difficult to steer. This problem is related to
un-optimized weight distribution ratio of the skis and a "wall"
effect of the keel. More specifically, during normal operation, the
snowmobile frequently places more weight in the front portion of
the skis than the rear portion of the ski. Further, the "wall"
effect of the keel is created where the ski resists turning in
response to the steering because the side wall 136 of the keel 130
runs into compacted snow when attempting to turn. Thus,
conventional skis such as shown in FIGS. 1(A)-1(I), which is the
most common type of the snowmobile skis presently available on the
market, are thought to have acceptable stability and aggressivity
characteristics while having poor steering characteristics.
[0051] A first embodiment of the snowmobile ski 10 made in
accordance with the principles of the present invention is shown in
FIGS. 2(A)-2(J). The components of the snowmobile ski 10 made
according to an aspect of the present invention are numbered with
the same reference numerals as the corresponding components of the
prior art snowmobile ski 110 shown in FIGS. 1(A)-1(I), except that
the reference numerals for the components of the prior art
snowmobile ski 110 start with 100.
[0052] As can be observed from FIGS. 2(A)-2(J), the front portion
22 of the bottom surface 20 of ski body 12 of the present invention
has a convex, curved cross-sectional shape, in contrast to the flat
side-to-side cross-sectional shape of the bottom surface of the
prior art ski shown in FIGS. 1(A)-1(I). The middle portion 24 and
the rear portion 26 of the ski 10, as shown in FIGS. 2(H) and 2(J),
have a substantially flat bottom surface except for the keel 30
extending downwardly from the bottom surface 20. The convex shape
of the front portion 22 of the bottom surface 20 of the ski body 12
is formed by a smooth curve formed by the front portion 22.
[0053] Furthermore, as shown in FIGS. 2(C)-2(F), the front portion
22 of the bottom surface 20 does not have a keel 30. The keel 30 is
provided only in the middle portion 24 and the rear portion 26. The
keel 30 extends lengthwise along the middle of the ski 10. That is,
the centerline of the keel 30 extending longitudinally is
substantially aligned with the centerline of the ski body 12 along
the longitudinal direction. As shown in FIGS. 2(G)-2(I), the keel
30 has a substantially trapezoidal cross section in the middle
portion 24 of the bottom surface 20 of the ski body 12. However,
the cross section of the keel 30 can be more curved than
trapezoidal, similar to the keels shown in FIGS. 4(D)-4(H) and
towards the rear end 19 of the ski body 12 as shown in FIG.
2(J).
[0054] In the embodiment shown in FIGS. 2(A)-2(J), the convex
curved bottom surface 20 of the ski body 12 meshes into the keel 30
where the keel 30 begins to extend downwardly from the bottom
surface 20 and to extend longitudinally rearward starting from the
middle portion 24 of the bottom surface 20.
[0055] Another embodiment of the present invention is shown in FIG.
3 and FIGS. 4(A)-4(J), with components having reference numerals
beginning with 200 corresponding to the components of skis
illustrated in FIGS. 1(A)-1(I) and FIGS. 2(A)-2(J). The second
embodiment of the present invention includes a smooth convex curved
protrusion 231 provided in the front portion 222 of the bottom
surface 220 of the ski body 212. The smooth curved protrusion 231
meshes or blends into the keel 230, which starts about in the
middle portion 224 of the bottom surface 220 of the ski body 212.
Thus, rather than the front portion 222 of the bottom surface 220
itself having a convex curved shape, the front portion 222 of the
bottom surface 220 has an additional smooth curve protrusion 231
that is connected to the keel 230. While a curved protrusion 231 is
preferred in the front portion 222 of the bottom surface 220, the
protrusion may have a substantially smooth trapezoidal
cross-sectional shape.
[0056] The keel 230 starts in a shape of a smooth convex curve near
the front portion 222 but gradually assumes more of a trapezoidal
shape. Like the first embodiment and the prior art ski shown in
FIGS. 1(A)-1(I), the keel 230 protrudes downwardly from the bottom
surface 220 in the middle portion 224 and extends longitudinally
along the middle of the ski body 212. In the second embodiment
shown in FIGS. 3 and FIGS. 4(A)-4(J), the lateral ends of the keel
230 blend with bottom surface 220.
[0057] In both the first and the second embodiments, the "wall"
effect which results in poor steerability characteristics is
reduced. In the first embodiment, since there is no keel 30 in the
front portion 22 of the ski 10, there is no side wall of the keel
30 to resist the steering of the ski at the front portion of the
bottom surface. In the second embodiment, the smooth curve
protrusions that blend into the keel offer less resistance to the
snow in comparison with the side walls of the keel of the prior
art.
[0058] Furthermore, the skis having no keels in the front portion
in accordance with the present invention provide an improved weight
ratio of the skis. Specifically, by eliminating the keel in the
front portion there is more surface area and less weight towards
the front of the ski and less surface area and more weight in the
middle and rearward portions of the ski when the ski sits in
powdery snow. In the prior art, there is more weight distributed
toward the front of the ski and therefore there is a more even
surface area and weight distribution towards the front of the ski.
Additionally, having no keel in the front improves the stability
provided by the skis by reducing incidents of pitching and
darting.
[0059] The foregoing detailed description of this invention has
been provided for the purposes of illustration and description. It
is not intended to be exhaustive or to limit the invention to the
precise embodiments disclosed. Other modifications and variations
may be evident to practitioners in the art when considered in
reference to this disclosure.
* * * * *