U.S. patent number 3,857,578 [Application Number 05/447,750] was granted by the patent office on 1974-12-31 for wear bar for a snowmobile ski.
This patent grant is currently assigned to James G. Alton Equipment Co., Limited. Invention is credited to James Gowan Alton.
United States Patent |
3,857,578 |
Alton |
December 31, 1974 |
WEAR BAR FOR A SNOWMOBILE SKI
Abstract
A wear bar for a snowmobile ski comprises two opposing steel
sides which are downwardly depending and which meet to form an
integral joint longitudinally of said wear bar. The joint has at
least one longitudinal edge for contacting the ground surface which
supports the ski. The wear bar may be case-hardened so that each
edge consists of hardened steel. In a depression defined between
the sides, fastening means are located to facilitate fastening of
the wear bar to the ski where the longitudinal edge is parallel to
the longitudinal axis of the ski. A wear bar of this structure
provides the snowmobiler with improved steering control at a
reasonable cost.
Inventors: |
Alton; James Gowan (Willowdale,
Ontario, CA) |
Assignee: |
James G. Alton Equipment Co.,
Limited (N/A)
|
Family
ID: |
23777601 |
Appl.
No.: |
05/447,750 |
Filed: |
March 4, 1974 |
Current U.S.
Class: |
280/28;
180/182 |
Current CPC
Class: |
B62B
17/02 (20130101) |
Current International
Class: |
B62B
17/02 (20060101); B62B 17/00 (20060101); B62b
017/02 () |
Field of
Search: |
;280/28 ;180/5R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Song; Robert R.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A wear bar for a snowmobile ski comprising two opposing steel
sides which are downwardly depending and which meet to form an
integral joint longitudinally of said wear bar, said joint having
at least one longitudinal edge for contacting a ground surface
which supports said snowmobile ski; said wear bar being adapted to
correspond with the contour of the underside of said snowmobile ski
where fastening means for securing said wear bar to the underside
of said snowmobile ski is positioned in a depression defined
between said opposing sides, the longitudinal axis of each said
edge being parallel to the longitudinal axis of said snowmobile
ski.
2. A wear bar of claim 1 which has been case-hardened whereby each
said edge consists of hardened steel.
3. A wear bar of claim 1 wherein said opposing sides meet at
substantially right angles, the shape of said valley being
"vee"-shaped, where said integral joint has one edge.
4. A wear bar of claim 3 wherein each end portion of said wear bar
is curved upwardly, the portion of said wear bar between said
curved end portions being substantially planar, said edge extending
at least along said substantially planar portion of said wear bar;
said end portions being tapered and extending at least above a
plane defined by the upper surface of said sides.
5. A wear bar of claim 3 wherein at least one metal plate having a
threaded hole formed therein is secured in said "vee"-shaped valley
below a plane defined by the upper surfaces of said sides; said
metal plates being spaced apart along the length of said valley
when there is more than one plate.
6. In a snowmobile ski assembly having a runner portion and a wear
bar adapted to be secured to the underside of said runner portion;
the improvement comprising said wear bar having two opposing steel
sides which are downwardly depending and which meet to form an
integral joint longitudinally of said wear bar, said integral joint
having at least one longitudinal edge for contacting a ground
surface which supports said snowmobile ski; said wear bar being
case-hardened whereby each said edge consists of hardened steel;
said opposing sides defining a depression therebetween wherein
fastening means is provided for securing said wear bar to said
runner portion, the longitudinal axis of each said edge being
parallel to the longitudinal axis of said snowmobile ski.
7. In a snowmobile ski assembly of claim 6 wherein said wear bar is
case-hardened, each said edge thereby consisting of hardened
steel.
8. In a snowmobile ski assembly of claim 6, said opposing sides of
said wear bar meeting at right angles, the shape of said valley
being "vee"-shaped, where said integral joint has one edge.
9. In a snowmobile ski assembly of claim 7, said runner portion
having a plurality of spaced-apart apertures formed therein; each
end portion of said wear bar being curved upwardly and extending
above a plane defined by the upper surfaces of said sides, said end
portions being tapered and adapted to be received by two of said
apertures; and means for co-operating with said fastening means to
secure said wear bar to said runner portion.
10. In a snowmobile ski assembly of claim 7, at least one metal
plate having a threaded hole being secured in said "vee"-shaped
valley below a plane defined by the upper surfaces of said sides;
said runner portion having a plurality of spaced-apart apertures,
each said threaded hole being aligned with the respective aperture
to permit securing of said wear bar to said runner portion by means
of a threaded bolt.
Description
FIELD OF INVENTION
This invention relates to improvements in a snowmobile ski assembly
and, more particularly, to wear bars for a snowmobile ski.
BACKGROUND OF THE INVENTION
Snowmobile skis having a runner portion usually have a wear bar
secured to the underside thereof which serves to reduce wear by
separating the runner portion from hard abrasive surfaces, such as
sand-covered ice. This type of wear bar is usually formed from a
cylindrical bar of cold rolled steel and it is expected to last for
only one season of snowmobiling because of its inherent inability
to resist abrasion.
A second drawback with this common type of wear bar is the lack of
steering control due to the rounded portion of the wear bar which
contacts the surface supporting the snowmobile ski, permitting the
wear bar to slide easily over the supporting surface. This is
frustrating for the snowmobile operator and can be very hazardous
when travelling in congested areas such as at snowmobiling events
and races.
Another type of wear bar which is available on the market and
usable on most snowmobiles is a bar having several "Carboloy"
(trade mark) metal pieces secured to the underside of the bar to
present a hard metal edge parallel to the longitudinal axis of the
ski where the edge bites into compacted snow, ice and the like, to
effect good steering control. However, the disadvantage of this
arrangement is that the method of assembly and material costs are
quite high so that the replacement or initial purchase cost of the
unit discourages one from using this type of wear bar.
The snowmobile ski assembly according to this invention has been
designed to overcome the above-noted problems by providing a wear
bar which effects good steering control and can be manufactured at
very low cost so that the snowmobile enthusiast may enjoy the
benefits of good steering control at a reasonable cost. The wear
bar comprises two opposing steel sides which are downwardly
depending and meet to form an integral joint longitudinally of the
wear bar. The joint is so formed to present at least one
longitudinal edge for contacting the ground surface which supports
the snowmobile ski. The wear bar is cold worked to the desired
shape or contour to fit snugly to the underside of the particular
snowmobile ski. Depending upon the degree of use, the wear bar may
be case-hardened so that each edge consists of hardened steel. To
facilitate securing of the wear bar to the snowmobile ski,
fastening means is positioned in a depression defined between the
opposing sides of the wear bar. The wear bar is secured to the
snowmobile ski in a manner which ensures that the longitudinal axis
of each edge is parallel to the longitudinal axis of the snowmobile
ski.
The wear bar may be fabricated from common angle iron where the two
opposing steel sides meet at substantially right angles and a
V-shaped valley is defined therebetween, the integral joint
presenting only one edge. In the instance where the angle iron is
case-hardened, it is formed prior to hardening to the contour of
the underside of the snowmobile ski to provide a hardened steel
portion along the length of the edge.
The configuration and location of fastening means of the wear bar
may vary from one type of snowmobile to another, however, such
variations may be easily accommodated by cold working the steel
material to the desired shape for making the wear bar according to
this invention. For example, with a snowmobile ski having three
spaced-apart apertures formed in the runner portion and aligned
with the longitudinal axis of the ski, both end portions of the
wear bar may be curved upwardly to extend above a plane defined by
the upper surfaces of the two sides of the wear bar, the curved end
portions being tapered so as to fit in the two furthermost
spaced-apart apertures. The fastening means is located in the
depression and is aligned with the central aperture in the runner
to permit securing of the wear bar to the snowmobile ski by means
of a bolt and/or nut.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a wear bar for a
snowmobile ski which provides good steering control while operating
the snowmobile.
It is a further object of the invention to provide a wear bar which
may be easily adapted during fabrication to fit any make of
snowmobile ski.
It is another object of the invention to provide a wear bar which
may be manufactured at low cost and effect good steering
control.
It is yet another object of the invention to provide a wear bar
which may be easily attached in the field to a snowmobile ski.
It is a further object of the invention to provide a wear bar which
may be manufactured from one type of stock steel material, and
subsequently, case-hardened to provide a durable supporting edge on
the wear bar for the snowmobile ski.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects, features and advantages of the invention
are discussed in more detail hereinafter in association with the
accompanying drawings in which:
FIG. 1 is an exploded view of a snowmobile ski assembly according
to a preferred embodiment of this invention;
FIG. 2 is a cross-sectional view of a portion of a snowmobile ski
having a wear bar according to this invention secured to the
underside thereof;
FIG. 3 is a cross-section along the lines 3--3 of the snowmobile
ski assembly of FIG. 2; and
FIG. 4 is a perspective view of a wear bar according to this
invention having an alternative fastening means arrangement.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A snowmobile ski assembly 10 is shown in FIG. 1 having a snowmobile
ski 12, a runner portion 14 and an upturned portion 16 at the
forward end of the ski where a handgrasp 18 is provided at the
forward portion of the ski to permit handling of the snowmobile. By
way of a standard spring apparatus, the snowmobile is connected to
the ski by brackets 20 and 22. Three apertures 24, 26 and 28 are
located in the runner portion 14 and are aligned parallel to the
longitudinal axis of the ski 12.
A wear bar 30 which is adapted to be secured to the underside of
the snowmobile ski is formed from angle iron and comprises two
opposing sides 32 and 34 which meet at substantially right angles
to define a depression 36 therebetween. End portions 38 and 40 of
the ski are curved upwardly and are tapered as shown. End portions
38 and 40 have tapered tips 42 and 44 respectively, both of which
extend above a plane defined by the upper surfaces of sides 32 and
34. Tips 42 and 44 are received by apertures 28 and 24 respectively
and fastening means 46 which is a metal plate having a threaded
hole is aligned with the central axis of aperture 26. Upon
insertion of tips 42 and 44 in the respective apertures, a bolt 48
and lock washer 50 are used to secure the wear bar 30 to the ski 12
by co-operating with fastening means 46. Once bolt 48 is securely
tightened, longitudinal and lateral movement of the wear bar 30
with respect to the ski 12 is precluded where tips 42 and 44 serve
to align the longitudinal axis of the wear bar with the
longitudinal axis of the ski so that the axes are parallel to one
another. Tip 42 may also function to preclude relative longitudinal
movement of the wear bar with respect to the snowmobile ski.
In FIG. 2, wear bar 30 is shown as secured to snowmobile ski 12 by
bolt 48 being threaded into fastening means 46. In assembling the
wear bar, tip 44 is placed in aperture 24 first and is inserted far
enough into aperture 24 to permit tip 42 to pass through aperture
28. Bolt 48 is threaded into the threaded hole of fastening means
46 which is aligned with aperture 26 to secure wear bar 30 to the
underside of ski 12.
In forming the wear bar 30, the upper surfaces of sides 32 and 34
of a straight standard piece of angle iron are machined in a
downwardly direction so that each end is tapered to a point. The
ends of the machined bar are then bent to form curved end portions
40 and 38. The tips 42 and 44 of the bar are then formed by bending
them the additional amount required to conform to the particular
ski design. Fastening means 46 is positioned in the V-shaped valley
defined between sides 32 and 34 so that when tips 42 and 44 are
placed in the respective apertures, the threaded hole of the
fastening means is aligned with aperture 26.
The fastening means 46 consists of a metal plate 52 as is more
clearly shown in FIG. 3. The plate has a threaded hole 54 of thread
corresponding with the thread of bolt 48. The metal plate 52 is
secured in the V-shaped valley by weld beads 56.
Sides 32 and 34 of the wear bar are downwardly depending from their
upper surfaces 58 and 60 which contact the underside of runner
portions 14 of the snowmobile ski. The downwardly depending sides
meet to form an integral joint 62 which is longitudinal of the wear
bar, where the sides meet at substantially right angles. As
mentioned hereinbefore, sides 32 and 34 may meet to form an
integral joint having more than one edge. In the preferred
embodiment shown in FIG. 3, the joint has a single edge 64 which
extends the full length of the wear bar.
Subsequent to the process of forming the wear bar to fit a
particular snowmobile ski, the wear bar may be optionally
case-hardened to provide hardened steel all the way along edge 64.
Depending upon the severity of use of the wear bar, it need not
necessarily be case-hardened in that the soft metal can withstand
some abrasion. However, when it is desired to make a long-lasting
wear bar which is subjected to a great degree of abrasion, the wear
bar may be case-hardened. Due to the shape of the angle iron of
wear bar 30, case-hardening of the portion of the angle iron which
constitutes the longitudinal joint 62 results in the joint
consisting substantially of hardened steel due to exposure on both
sides of the joint to the case-hardening process. In using angle
iron having approximately one-inch wide sides of 1/8 inch
thickness, the case-hardening of the angle iron provides sufficient
hardened steel along edge 64 to permit extensive wear before soft
metal of sides 32 and 34 inside the case-hardened metal is exposed
to abrasive ground material. However, before edge 64 is worn down
to the extent to expose the softer metal, the wear bar would in all
likelihood be replaced because steering control of the snowmobile
would be reduced due to edge 64 having a certain degree of
roundness caused by wear.
Wear bar 30 may be case-hardened according to accepted
manufacturing practices where the case-hardening is carried out to
the extent to ensure that edge 64 consists of hardened steel. End
portions 38 and 40 of the wear bar are formed and machined to
conform to the contour of the underside of runner portion 14,
particularly at the front portion 38, to preclude snagging of weeds
and branches on the underside of the ski during travel over rough
terrain and in bush country. Although not necessary, it is
advantageous to have edge 64 extend upwardly along curved portion
38 so that edge 64 is gently leading into the supporting surface
thereby permitting the edge to obtain a good bite in the supporting
surface. Good steering control is therefore realized by edge 64
preventing side-slipping of the snowmobile skis during turning of
the vehicle.
The wear bar 30 may be adapted to fit any type of snowmobile ski
during its formation from the stock steel material where the
curvature of the upper surface of the wear bar, the number of
apertures and the type of fastening means used in attaching the
wear bar, may vary. The wear bar shown in FIG. 4 illustrates an
adaptation of the wear bar 30 wherein two fastening means 66 and 68
are provided, each having a threaded hole formed therein. Tips 42
and 44 remain unchanged, the wear bar 30 being adapted to fit on a
snowmobile ski wherein two apertures are provided for bolts to pass
therethrough to distribute more evenly the reactive forces and to
resist forces exerted on the wear bar which tend to move the wear
bar longitudinally and laterally of the ski. Variations in the
length of the wear bar and the curvatures of the end portions 38
and 40 are also easily accommodated in forming the wear bar from
the angle iron stock material. Other shapes of stock material may
be used in forming the wear bar such as iron formed in the shape of
a "W", or channel iron having one or more edges projecting from the
underside thereof.
While various embodiments of the invention have been described and
illustrated herein, it is understood that variations may be made
thereto as will be apparent to those skilled in the art without
departing from the spirit of the invention or the scope of the
appended claims.
* * * * *