Note: Descriptions are shown in the official language in which they were submitted.
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Field of the invention
This invention relates to endless tracks used to propel tracked vehicles
[i.e., vehicles which use
endless tracks rather than tires to contact the terrain over which they are
driven, e.g., tractors, tanks,
bulldozers, etc.] and, more particularly, to one split wheel which allows for
easier and more efficient
method of installing the endless track on a tracked vehicle.
Background of the invention
t o [NOTE: As used herein, the term "rubber" relates to any elastic and
primarily non-metallic materials
such as rubber, elastomers, or combinations thereof used in the manufacture of
endless tracks].
Numerous types of vehicles are frequently used in terrain in which it is
difficult for pneumatic tires
to operate. Both defense vehicles, such as tanks and amphibious vehicles, and
civilian vehicles, such
as tractors and recreational vehicles, are sometime utilized on terrains which
are very soft, for
example sand surfaces. Pneumatic tires are not capable of efficient operation
on such soft surfaces,
as they tend to burrow into the surface, rather than riding across the
surface.
In the past the most popular type of track for heavy duty vehicles have been
metallic tracks.
2o However, these metallic tracks still present significant inconveniences in
relation to wheeled vehicle.
Some of these problems can be summarized as follows:
~ Noise. The metallic track produces an excessively high level of noise. This
fact can cause a
significant strategic disadvantage when used in association with defense
vehicles since the
enemy can detect their presence many miles away.
~ Damage. With respect to civilian vehicles equipped with such tracks or
defense vehicles
used in peace keeping missions, the metallic tracks can cause significant
damage to the
ground surface whether it be paved or not.
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Weight. Metallic tracks are very heavy. For example the, typical weight of a
metallic track
used on an M 113 vehicle is 1200 pounds while metallic tracks used on a
fighting vehicle can
be above 2500 pounds. Such a weight is both an inconvenience with respect to
the mobility
of the vehicles and with respect to their consumption of fuel.
Short lifespan. Metallic tracks have a short lifespan. Even metallic tracks
provided with
rubber pads wear out extremely rapidly such that the pads need to be replaced
typically every
500 to 1000 miles on a defense tank.
Maintenance. Metallic tracks also require a lot of maintenance. The
replacement of the
rubber pads, the metallic links or pivots, etc, require a continuous
maintenance of the tracks.
~ Costs. Finally, the cost of manufacturing, maintenance and refurbishing are
extremely high.
Recently, endless rubber tracks have become popular because of an increase in
construction. With
the combination of rubber technology and a tremendous amount of trial and
error, various types of
rubber tracks are now available in the industry. They are used on defense
vehicle, excavators, dump
Garners, boring machines, combines, tractors, and the like.
While rubber endless tracks are often desirable since they reduce damage to
the terrain, reduce noise
and allow access to various types of soil, they do have some drawbacks
concerning their installation
and removal. Usually, once installed the track is carried and maintained in
tension by a plurality of
rotating elements (wheels, sprockets, etc...) that are connected to the
vehicle. The tracks being
maintained in circumferential contact with these rotating elements are being
driven thereby (or, in
the case of trailer-like non-driven vehicles, being supported for rotation
thereon).
Metallic tracks which are often formed by a number of individual pieces
fastened together can be
separated into a single strip thus allowing installation onto the plurality of
rotating elements. This
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method has been in place for many years.
Rubber tracks on the other hand are usually formed of a single continuous
piece, and it is typically
difficult and may require special equipment to mount them around the plurality
of rotating elements,
or remove them when maintenance or access is needed on the vehicle. This is
especially true with
tracks for heavy duty vehicles where the tracks can weigh a substantial
amount.
As rubber tracks have grown more popular it has become apparent that the best
way of installing a
new track involves the removal of one or more of the wheels or other rotating
elements from the
1 o vehicle. While the removal of the wheel rotating elements allows the
firack to be slid around the drive
assembly with more ease, reinstalling the wheel rotating elements still may
pose problems.
The present invention sets out to solve the problem of installing or removing
a rubber endless track
by providing a special wheel (tension wheel, sprocket wheel, etc...) which is
split into sections
15 (when viewed from the side). The parts may be installed separately and will
form a complete tension
wheel when fully installed.
The idea of splitting a wheel into multiple pieces is not new, though it has
not previously been
adapted for use with endless track installation.
Previous split wheel assemblies can lie found in United States patents
4,631,974 (Weigland et al.),
5,080,852 (Hertel et al.), and 5,868,036 (Salzman).
US 4,631,974 Weigland et al. describes a split sprocket wheel for applications
which are either
submerged or in a corrosive environment. The wheel of the Weigland patent is
made up of two
portions of a circular wheel. During installation the two pieces of the wheel
are put around a drive
shaft and fastened together by multiple means, such as a circular band clamp
and a plurality of
wedge dog assemblies. US 5,080,852 Hertel et al. describes a method for making
a bearing sleeve
for a split sprocket wheel assembly such as the one described in the Weigland
patent.
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US 5,868,036 Salzman describes a split transfer wheel which is used to impart
movement to other
materials. The wheel comprises two wheel halves which are held together by
multiple bolts. The
construction of the wheel allowing for a strip of a tire material to be held
in place around the wheel,
and said strip of tire material being replaced if worn out.
While the above split wheels are useful in their own areas, the construction
of the wheels
unfortunately do not allow them to be useful in the field of endless track
installation. The reason for
this is that the wheels of the Salzman and the Weigland patents need to be
fully assembled to
1 o function. For the installation of endless tracks it is useful to have a
split wheel which allows for one
portion of the wheel to be installed and function without the other portion of
the wheel being
installed.
Summary of the invention
The objective of this invention is to provide a workable solution to the
rubber endless track
installation problems, since such a track is mostly made from one single
continuous rubber part, thus
requiring special tools or equipment at installation. The rubber endless track
had originally been
invented as a compromise to metal tracks, proposing a wider range of
commercial and residential
2o applications for a tracked vehicle, with a lower cost and at a lower
weight.
With the increase in popularity for such a rubber track came the necessity to
provide the means for
an easier installation process, since the track installation, removal and the
maintenance procedures
can sometimes be required in a variety of environments, or in remote and/or
inconvenient locations.
The invention provides a step by step method of installation of an endless
rubber track on a vehicle
using a split wheel which replaces the tension wheel or the drive sprocket on
the typical tracked
vehicle configuration.
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There is therefore provided a split sprocket wheel for use with an endless
track, comprising:
a first section defining a deep pie angular portion of said wheel and
a second section defining another deep pie angular portion of said wheel;
said first section and said second section being configured such that said
first section may be
fastened to a.supporting shaft separately from the second section.
In another embodiment, a split spraCket wheel for use with an endless ri-ack,
comprising:
a first section defining a deep pie angular portion of said wheel and
a second secrion defining another deep pie angular portion of said wheel
a third section defining still another deep pie angular portion of said wheel
;
said first section, said second section and said third section being
configured such that said first
section and said third section nnay be fastened to a'supporting shaft without
said second section
being fastened to said supporting shaft.
There is also provided a method of installing an endless track on a tracked
vehicle equipped with
a plurality of wheels and a split wheel, said split wheel comprising:
a first section which defines a first deep pie angular portion of said split
wheel and
a second section which defines another angular portion of said split wheel ;
said method comprising the steps of:
a) insuring said split wheel is removed from the said vehicle;
b) placing said endless track over said plurality of wheels;
c) installing said first section on the vehicle such that said first angular
portion of the split
wheel faces away from said endless crack;
d) rotating said first section such that said first angular portion of the
split wheel faces
said endless track, to tension said endless track around said plurality of
wheels and said
first section.
e) installing said second section on said vehicle.
While the invention method and use of a split wheel is meant to facilitate the
installation process of
3o a rubber track on a tracked vehicle, one particular purpose is to lower the
cost and reduce the time
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required to complete the installation or replacement of a rubber track. A
simpler method with the use
of many standard tools will also benefit to the customer by increasing
possibilities of fixing field
problems.
Other aspects and many of the attendant advantages will be more readily
appreciated as the same
becomes better understood by reference to the following detailed description
and considered in
connection with the accompanying drawings in which like reference symbols
designated like
elements throughout the figures.
1 o The features of the present invention which are believed to be novel are
set forth with particularity in
the appended claims.
Brief description of the figures
1 s Accordingly it is intended that the foregoing disclosure and showing made
in the drawings shall be
considered only as an illustration of the principle of the present invention.
FIG. 1 is a partial side view of a tracked vehicle making use of a split
tension wheel in accordance
with the invention;
FIG. 2 is a rear view of the vehicle shown in Figurel;
FIG. 3 is a partial rear view showing the endless rubber track alongside the
vehicle shown in Figure
1;
FIG. 4 is a partial side view of the vehicle on which the rubber track has
been partially installed;
FIG. 5 is a partial side view of the vehicle on which the vehicle has been
lowered on the rubber
track;
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FIG. 6 is a perspective view showing the first half of a drive sprocket being
installed on its
supporting shaft;
FIG. 7 is a perspective view showing the rubber track being installed on the
first half of the drive
sprocket;
FIG. 8 is a perspective view showing the second half of a drive sprocket being
installed with the first
half of the drive sprocket and the rubber endless track;
to
FIG: 9 is a partial side view of a tracked vehicle on which the rubber track
gap between the drive
sprocket and the first road wheel has been minimized;
FIG. 10 is a perspective view showing the tension wheel supporting shaft and
the rubber track before
the installation of the first section of the tension wheel;
FIG. 11 is a perspective view of the first section of the tension wheel being
installed;
FIG. 12 is a partial side view showing the first section of the tension wheel
being rotated;
FIG. 13 is a perspective view of the second section of the tension wheel being
installed;
FIG. 14 is a partial side view of the tension wheel area on which pressure is
applied on the tension
wheel cylinder;
Detailed description of a preferred embodiment
FIG 1. shows a general side view of a split tension wheel system in accordance
with this invention
and installed in this embodiment on a defense vehicle 100. The vehicle
comprises an endless
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reinforced rubber track 120, a sprocket drive 130, a split tension wheel 140
and a plurality of road
wheels 150 which support the vehicle and guide the track 120. This system is
coupled to appropriate
drive means (not shown) through an appropriate suspension system (not shown).
A similar system
is disposed on the other side of the vehicle 100.
Although the method explained herein is described in relation to the
installation of an endless track
on a vehicle, it is also applicable for the removal of the endless track from
the vehicle. As shown in
FIG. 2, the vehicle 100 needs to be lifted one side at a time with a typical
jacking equipment 10 in
order to install the endless rubber track 120 (see FIG. 1).
As shown in FIG. 3, the rubber track 120 needs to be laid along the plurality
of road wheels 150 in
the required direction of operation. The upper portion 121 of the rubber track
120 is lifted and
disposed over the plurality of road wheels 150, as shown in FIG. 4, followed
by the sliding of the
rubber track 120 lower portion 126 under and aligned with the plurality of
road wheels 150.
. 15
FIG. 5 shows the resulting configuration after the jacking equipment 10 (see
FIG. 2) has been
removed and the vehicle 100 and its plurality of road wheels 150 have been
lowered on the lower
portion 126 of the rubber track 120. By hand or by moving the vehicle back,
the gap 20 between the
endless track 120 and the last road wheel 155 is kept as small as possible.
As illustrated in FIG 6., the inner half 131 of drive sprocket 130
(longitudinal split of the drive
sprocket 130) is installed on its shaft hub 135, then becomes available as
support for the upper part
121 of the endless tracks 120 (see FIG. 4). FIG. 7 shows how to position the
rubber track 120 on top
of the inner half 131 of drive sprocket 130 by engaging the rubber track inner
lugs (not shown) into
the formed gorge 134 of the drive sprocket 130 (see FIG. 6, only one shown).
The outer half 136 of
drive sprocket 130 is assembled with the inner half 131 of drive sprocket 130
and in conjunction
with the rubber track 120, by still having corresponding rubber track lugs 123
(only one shown)
inserted in the formed gorge 134 (only one shown) of the outer half 136 of
drive sprocket 130, as
shown in FIG 8.
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As shown in FIG. 9, tension is obtained in segment 129 of the rubber track
120, which is located
between first road wheel 151 and drive sprocket 130, with engine power
rotating drive sprocket 130
backward, thus providing the maximum rubber track play near its end 127.
FIG. 10 shows that separated rings 144 are positioned on the innermost side of
the tension wheel
shaft hub 143 in order to provide a clamping device. Once the first half 141
of tension wheel 140 is
positioned towards the front of the vehicle, as shown in FIG.11, separated
rings 144, tension wheel
shaft hub 143 and the first half 141 of tension wheel 140 are hand-tightened
together.
As illustrated in FIG. 12, the rotation of the first half 141 of tension wheel
140, induced by moving
the vehicle forward (with engine power), offers space provision for the
installation of the second half
146 of tension wheel 140 and simultaneously provides greater tension to the
rubber track 120 along
the process. FIG.13 shows the final tension wheel assembly on the vehicle 100
with the addition of
the second half 146 of tension wheel 140 and a full ring 145 positioned on the
outermost face of the
tension wheel assembly, thus ensuring a complete tightened clamping system.
Finally, the rubber track 120 is preferably tensioned to a greater degree, by
applying pressure to the
tensioning system 160, as shown in FIC'J. 14.
The same step by step method is also applicable for the installation of the
endless track with a split
tension wheel on the other side of the vehicle 100.
'Jfhile a preferred embodiment of the invention has been described herein, it
should be apparent to
those skilled in the art that variations and modifications are possible
without departing from the spirit
of this invention.
