Note: Descriptions are shown in the official language in which they were submitted.
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This invention is directed toward a drive track unit for
addition to a wheeled vehicle.
The invention is particularly directed toward a drive track
unit for addition to a recreation vehicle having two rear drive
wheels, the drive track unit adapted to be positioned between the
rear wheels and to replace them as the main drive means for the
vehicle.
Wheeled recreation vehicles of the type known as all-terrain
vehicles or ATV's employ large, low pressure tires and can be
equipped with two front and two rear wheels, or one front and two
rear wheels. The rear wheels are usually the drive wheels. The
vehicles carry a single rider and can be used over various types of
terrain such as smooth or rough ground, swamps, sand or snow.
In snow, however, the wheeled vehicle does not have a good
traction as is desirable. It is known to replace the rear drive wheel
or wheels of vehicles with tracks units to provide better traction on
snow. However, when modifying vehicles with two rear wheels, two
track units are usually employed. This makes the conversion to a
track drive relatively expensive, and also makes the conversion
operation relatively complicated.
It is the purpose of the present invention to provide a
drive track unit for a vehicle having two rear drive wheels that
simply and easily converts the vehicle to a rear track drive vehicle.
A single track unit is employed that is designed to be mounted
between the rear wheels of the vehicle and in a position to replace
the wheels as the driving means. With the use of the single track
unit, conversion of the vehicle from a rear wheel drive to rear track
drive is relatively simple. The rear drive wheels need not be
removed. In fact, retention of the rear drive wheels with the track
unit provides a vehicle having better cornering properties in snow
since the drive wheels come into play providing additional stability
and traction to the vehicle. The track unit is designed to be mounted
to the existing frame of the vehicle, directly or indirectly, at two
longitudinally spaced-apart locations so as to securely connect the
track unit to the vehicle. Litt]e modification is needed to the
vehicle to receive the track unit.
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The invention is particularly directed to a drive track
unit for converting a rear wheel drive vehicle, having at least
two rear drive wheels driven by power means, to a rear track
drive vehicle. The drive track unit has a support frame for
supporting a trac]c assembly haviny a track with an upper and
lower run, the support rame sized to fit between the rear wheels
of the vehicle. First connecting means are provided on the
front of the support frame for use in connecting the support
frame to the vehicle in front of the rear wheels. Second connec-
ting means are providea on top of thè support ~rame, intermediateits ends for use in connecting the support Erame to the rear
of the vehicle, between the rear wheels. The second connectincJ
means are dimensioned to locate the lower track run oE the track
assembly in a position, relative to the rear wheels of the vehicle,
to provide the main drive for the vehicle. Drive means are
provided at the rear of the support frame for use in connecting
the power means of the vehicle to the trac]c unit to operate
the track assembly.
The invention will now be described in detail having
reference to the accompanying drawings in which:
Fig. 1 is a perspective view of the drive track unit;
Fig. 2 is a side view of the track unit;
Fig. 3 is a front view of the track unit;
Fig. ~ is a side view showing the drive track unit installed
on a wheeled vehicle; and
Fig. 5 is a rear view of the drive unit when installed
on a wheeled vehicle.
The drive track unit 1 or the present invention, as
shown in Figs. 1 to 3, has a main frame 3 supporting a track
assembly 5. The main frame 3 has two parallel side supports
7, 9. Cross-bars connect the side supports 7, 9 together to
provide a rigid main frame 3. A rear cross-bar 11 extends between
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a pair of brac]cets 13, 15 extending rearwardly from the back
ends 17, 19 of the side supports 7, 9 respectively. The rear
cross-bar 11 is fixed to the brackets 13, lS and extends trans-
versely of the side supports 7, 9. An intermediate cross-bar 21
extends between the side supports 7, 9 slightly in front of
the mid-length point of the side supports. The intermediate
cross-bar 21 extends transversely across the top sides 23, 25
of the
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of the side supports 7, 9 and is fixed to brackets 27, 29 mounted on
the outer sides of the sides supports 7, 9.
A front cross-bar 31 joins the front ends 33, 35 oE the side
supports 7, 9 respectively. The front cross-bar 31 is of inverted
U-shape having a top, horizontal member 37 and downwardly directed,
vertical members 39, 41. First mounting means in the form of a
mounting bracket 43 is fixed to the top of the top member 37 of the
front cross-bar 31 for use in mounting the drive track unit 1 on a
wheeled vehicle as will be described. The front cross-bar 31 is
indirectly mounted on the side supports 7, 9. Mounting bars 47, 49
extend forwardly from the front ends 33, 35 of the side supports 7, 9
respectively. The mounting bars 47, 49 are longitudinally adjustably
mounted in the side supports 7, 9 and mount the track assembly 5 at
their front ends 51, 53 as will be described. Forwardly, upwardly
curved brackets 55, 57 are fixed on the mounting bars 47, 49 behind
their front ends 51, 53. The lower ends of the vertical members 39,
41 of the front cross-bar 31 are pivotally connected to the free ends
of the brackets 55, 57 by pivot members 59, 61.
The track assembly 5 has an endless belt 63 with an upper
run 65 and a lower run 67 mounted over idler sprocket wheels 69 at
the front of the unit, drive sprocket wheels 71 at the rear of the
unit, and bogies 73 between the idler and drive wheels 69, 71. There
are two idler wheels 69 rotatably mounted on a front shaft 75. The
front shaft 75 is fixedly mounted between the front ends 51, 53 of
the track unit mounting bars 47, 49 to connect the front of the track
assembly 5 to the frame 3. There are two drive wheels 71 fixedly
mounted on a rear drive shaft 77. The rear drive shaft 77 in turn is
rotatably mounted on brackets 79 located on the bottom sides 81, 83
of the side supports 7, 9 ad~acent their rear ends 17, 19 to connect
the rear of the track assembly 5 to the frame 3. The bogies 73 are
mounted on each side of the track assembly 5 either directly from the
side supports 7, 9 by suitable means (not shown) or indirectly by a
support frame (not shown) mounted to the side supports. The mounting
of the bogies 73 is well known. The track 63 has two parallel rows
85, 87 of openings 89, 91 which cooperate with sprockets on the idler
and drive sprockets wheels 69, 71 to drive the track 63 about the
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wheels when drive sprocket wheels 71 are rotated as is well
known. While one Eorm of track assembly 5 has been described,
other knol,7n forms of track assemblies can be usecl.
Drive means 95 are provided on the unit for use in rotating
the drive shaft 77 so as to drive the track 63. The drive means
95 includes a chain drive shaft 97 mounted on the top of the
side supports 7, 9 adjacent their rear ends 17, 19. ~he chain
drive shaft 97i~is rotatably mounted between a pair of brac}cets
99, 101 on the side suppor~s 7, 9. The bracket 99 can be adjus-
10 tably mounted on the top of the side support 7 for adjustmentin a longitudinal direction. A portion 103 o~ the chain drive
shaft 97 projects outwardly past the bracket 99. A firs-t chain
drive sproc];et 105 is fi:~edly mounted on the projecting portion 103
of the shaft 97. A second chain drive sprocket 107 is mounted
on the other end portion 109 of the chain drive shaft 97 which
projects just past the bracket 101. A third chain drive sprocket
111 is mounted on the drive shaft 77 beneath the second chain
sprocket 107. Sprocket 111 is adjacent the outer side of support
9. A chain 113 is mounted over the second and third chain drive
2~ sprocXets 107, 111. A casting 115, mounted on the side support
9, can enclose the chain 113 and sprockets 107, 111.
Second mounting means 119 are provided on the drive
track unit 1 for use in connecting it to the vehicle. The second
mounting means 119 comprise axle brackets 121, 123 mounted on
the top sides 23, 25 of the side supports 7~ 9 just rear~ardly
o~ the intermediate cross-bar 21. ~3ach axle bracket 121, 123
has a hinged top clamp 125 that cooperates ~7ith a base 127 to
define a circular opening 129 for receiving a vehicle axle housing
as ~ill be described.
Slider bars 131, 133 can be mountecl Erom the intermediate
cross-bar 21 to bear on the upper run 65 of the krack 63 to improve
its operation.
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The drive track unit 1 is adapted to be used with an
ATV 141 of the type having one ~ront wheel 143 and a pair of
rear drive wheels 145, 147 mounted on an axle 149 as shown in
Figs. 4 and 5. The axle 149 is driven by the power means (not
shown) of the vehicle. The vehicle 141 is slightly modified
to have a fourth chain drive sprocket 151 mounted on the axle 149
adjacent on rear drive wheel 145. A mounting bracket 153 is
also provided on the bottom frame 155 of the vehicle between
the front and rear wheels.
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The mounting bracket 153 can be adjustably mounted ~n the rame 155.
The drive track unit 1 is mounted onto the vehicle 141 between its
rear drive ~heels 1~5, 1~7 with the axle brackets 121, 123 clamped
onto the axle housing tube 157 of the vehicle adjacent the rear
wheels 145, 1~7. The front mounting bracket 43, pivotably moun-ted
on the track unit 1, is bolted or otherwise detachably fastened to
the vehicle mounting brac~et 153 on the vehicle frame 155. A drive
chain 159 is connected between the Eourth chain drive sprocket 151
on the vehicle 141 and the first chain drive sprocket 105 on the
drive track unit 1. Power is transmitted to the track unit 1 via
drive chain 159, and Erom drive shaft 97 carrying the ~irst chain
drive sprocket 105, to the drive shaft 77 oE the track assemhly 5
by chain 113.
The drive traclc unit 1, when attached to vehicle 141, has
the lower run 67 of track 63 positioned even with or just below the
bottoms of the rear drive wheels 145, 147 to provide the main drive
_maa~ for the vehicle. However, -the rear drive wheels 145, 1~7
assist driving the vehicle in deep snow and turns.
The tension OI the tracks 63 can be adjusted by adjusting the
20 ~ mounting bars 47, 49 on which the front shaft 75 of the track assem-
bly is mounted. The tension of the drive chain 159 can be adjusted
by adjustiny the position of the bracket 99 on the side support 7.
Applicant's drive track unit allows as wide a track unit as
possible to be located between the drive wheels of a vehicle. ~ith
horizontal chain drive 159 located above the upper run 65 of the
track unit, no casing is needed to protect it from snow and/or brush.
A casing 115 is used on vertical chain drive 113 but this casing is
located behind the wheels where there is room for it. The use o:E
two chains and drive shaft 97 also allows the sproc]~ets 103, 107 to
be set to yive the most e~ficient power transmission. This is im-
portant in keeping the unit as small and as compact as possible.
