Note: Descriptions are shown in the official language in which they were submitted.
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SEGMENTED AIR-TRACK APPARATUS
BACKGROUND OF THE INVENTION
_ . . _ .
This invention relates in general to buoyant-wheel
vehicles and, in particular, to an improved all terrain vehicle.
More specifically, but without restriction to the
embodimentsshown and described, this invention relates to an
all terrain vehicle utilizing a segmented air-track crawler
to support the vehicle for movement over various terrain.
Due to the wide variations of terrain over which
it is necessary to transport materials and people, various
vehicles have been developed for movement over difficult
terrain. Such vehicles must be capable of movement over not
just land surfaces, but also water and combinations whereof
under varying conditions and situations. For example, sand
beaches, marshes, mud flats, peat bogs, water, whether deep,
shallow, or weed infested, ice, which may be over or under
water, or ground, which due to cyclic weather conditions can
vary between clinging mud and frozen tundra are but some
examples over which such vehicles must traverse.
Supporting vehicles for movement over such difficult
¦ terrain can generally only be accomplished by the use of either
an air-cushion vehicle or a buoyant-wheeled vehicle. I~ile
! aircraft could certainly be used for operation over such ter-
j rain, their power requirements, and, thereEore, energy con-
sumption, are relatively high. In additiont the only type of
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aircraft which would be potentially suitable are he:Licopters
which themselves could not be landed in much of this terrain.
As a result, amphibious air cushion vehicles and buoyant-wheeled
vehicles have proven to be very effective or use in these
specialized circumstances. Both types of vehicles have very
low ground pressure, and neither cause much disturbance to the
surface over which they are operating, either from their means
of support or propulsion.
The principal drawback of air-cushioned vehicles is
the limitation to their grade climbing capability, and their
inability to pass from one surface to another where the gradient
between the level of the two surfaces exceeds a predetermined
¦ amount. These disadvantages are not present with a buoyant
wheeled vehicle which possesses considerable grade climbing
capability, and the ability to pass rom one surface level
to another whether the surfaces be of the same or different
materials. These buoyant-wheeled vehicles use low pressure tires,
; which are in effect trapped air cushions, which reduce ground
pressure by increasing footprint area. However, such vehicles
have disadvantages in that they have limited increase in
footprint area, are expensive to build, replace and service.
In addition, the use of such buoyant-wheeled vehicles requires
a large single high silhouette casing tire which is difficult
to service or replace in the field, and severe damage to such
tires requires that the entire unit be replaced and the damaged
casing discarded.
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A vehicle described herein is capable of utilizing
two 7' x 7' tracks in tandem having 98 sq. ft. of weight
bearing area covering almost the entire base of the vehicle.
The vehicle will support 6115.2 pounds per foot of immersion
in water, that means it will float one foot deep at 6115.2
wounds gross weight. Floating two feet immersed, the tandem
7' x 7' dual track vehicle will carry 12,230.4 pounds gross
weight. At internal track air pressures of l p.s.i. The above
tandem track vehicle will carry 7 toys and float 27" immersed
in water. At track pressures of 2, 3, 4, and 10 p.s.i., the
vehicle will carry 14, 21, and 70 tons gross weight respectively
SUMMARY OF THE INVENTION
It is, therefore, an object of this invention to
improve vehicles for operation over difficult terrain.
Another object of this invention is to improve
buoyant-wheeled vehicles.
A further object of this invention is to utilize
a segmented buoyant-wheel in a crawler configurationO
These and other objects are attained in accordance
with the present invention wherein there is provided a buoyant-
wheeled vehicle for operation over difficult terrain utilizing
low ground pressure supports combined in a crawler configuration.
DESCRIPTION OF THE DRAWINGS
Further objects oE the invention, together with
additional features contributing thereto and advantag~!s accruing
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therefrom will he apparent from the followi.ng description of
one embodiment of the invention, which is shown in the accom-
panying drawings, with like reference numerals indicating
corresponding parts throughout:
FIG. 1 is a side profile view of a vehicle
utilizing a segmented air-track crawler for
movement of the vehicle over difficult terrain;
. FIG. 2 is an enlarged perspective view of
one of the segmented air-track crawlers with
portions broken away to better illustrate the
construction thereof;
: FIG. 3 is a transverse cross sectional view
of one of the segmented air-track crawler units
to better illustrate the construction thereof;
FIG. 4 is a partial, longitudinal cross
sectional view taken through line 4-4 of FIG. 3 of
the segmented air-trac~ crawler to illustrate the
internal construction thereof;
FIG. 5 is a cross sectional view of the
apparatus shown in FIG 4 taken along lines 5-5;
FIG. 6 is a vertical planar internal view
of a portion of the air bearing seal utilized
in the segmented air-track crawler;
FIG. 7 is an enlarged cross sectional view
of the apparatus shown in FIG. 5 taken along
lines 7-7;
rIG, 8 is an enlarged view of one of the
segments of the air-track crawler;
FIGS. 9 and lO are additional views of the
structure shown in FIG. 8 taken in the direction
of lines 9-9 and lO-10, respectively;
. FIG. ll is a perspective view of the drive
framework for a crawler unit;
FIGS. 12 and 13 are, respectively, enlarged
perspective and cross sectional views of the
sealing system used for an air-track unit;
FIG. 14 is a side profile view of another
embodiment of a tandem air-track articulated
crawler vehicle;
; FIG. 15 is a bottom view of a tandem air-
; track articulated crawler vehicle of FIG. 14
showing pull width crawler belts; and
FIG. 16 is a front view of the tandem air-
track vehicle.
DESCRIPTION OF THE PRl~FERRED EMBODIMENTS
Referring now to FIG. l, there is shown a vehicle lO
for operating over difficult terrain which utilizes a plurality
of segmented air-track crawlers lO0 for propelling and carrying
the ve icle over its supporting surface. An operator's
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compartment 11 is supported both fore and aEt of the vehicle,
and contains all of the operational controls for effecting
vehicle movement and functions. The vehicle 10 includes a bed 12
in which materials may be carried, and at lleast four segmented
air-track crawlers 100 to support the vehicle. Since these
segmented air-track crawlers are identical to each other,
only one is described in detail in the specification.
The segmented air-track crawlexs 100 which support
the vehicle 10 for movement over the terrain, include a plurality
of individual air-track segments 110 carried by a oluralitv of
drive chains 120 which are supported for movement in an endless
path of movement upon sprocXets 121 rotatably supported uoon
shafts 122 and which define the run length. Each of the
sprockets 121 are supported on the shafts 12Z by suitable
tapered bushings 123 and keyed 124 to the shaft for rotation
therewith. As best shown in FIGS. 2 and 3, the individual
air-~rack segments flare formed, for example, from a rubber
material such as normally used for buoyant-wheeled vehicles,
with each of the individual segments 110 being bolted to a
I T-shaped support member 130 to support an airtight sliding
seal 151 therewith. The T-shaped supports 130 are also secured
to the links of the drive chains 120 for a purpose hereinafter
described.
The top of each air-track segment is maintained flat
by means of an internal tension cable or cord 111 within each
individual air-track segment 110 as best shown in FIGS. 8~10.
¦ The molded into the rubber, or integral, tension cable 111
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is supported at one end llla by a loop to a bolt lllc (FIG. 3
anchoring the air-track segment to the T-shape support member
130 with its other end lllb of the cable beiny secured to the
opposite s ide o the segment to the skid rest bolt lllb. Cain-
:taining the cable 111 under tension keepr the top of the air~track
segment flat and prevents ballooning. Two central tables cross
diagonally between the inside skid rest bolts.
Within the structure of the individual air~track
segment 110~ a pair of skid rests 112 (FIGS. 3, 4t and 5) are
10supported from the drive chains 120 and through bolted 113
between adjacent segments to form a support for the vehicle
when the air pressure in the segmented air-track crawler unit
is turned off. In this manner, when power is turned off, the
vehicle will not come to rest on the sprockets 121, but will
be supported by the plurality of skid rests 112.
; Outside the air-track unit shown in FIG. 13 lS .
an alternative external skid rest 112a located on both sides
oE the air-tracX unit and secured to the main frame 140a.
Air pressure for maintaining the desired ground
pressure relationship is introduced into the segmented air-track
crawler unit through an air pressure inlet 141 (FIG. 11),
¦ mounted in a frame 140a which communicates air pressure within
the air-track crawler unit to the in~ivldual air-track segments
110~ The individual air-track seyments 110 forming tne segmented
air-track crawler 110 (FIGS. 2 and 3), are fastened to the
T-shap supports 130, which in turn are fastener by the
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interlinking chain pins 129 to the chain 1 0. Chain pins 129
also fasten expandable bellows seal 15~ having a Teflon or
other low friction material, sealing face 151 adhesively
secured thereto. The individual air-track segments 110 are
sealed to one another at their sides by means of the internal
bolts 113 which also fasten the segments 110 to the skid rests
¦ 112 as shown in FIGSo 4 and 5. Teflon is a trademark of
DuPont Corp. for a fluorocarbon product. The Teflon or other
low friction material, sealing face 151 is held in sealing
engagement with the interior face of the air maniold 140
Icarried on each side of the air-track crawler by the support
¦ frame 140a within which the shafts 122 are rotatably supported.
As best shown in FIGS. 3 and 12, the seal formed
by the expandable bellows seal 150 and Teflon face 151 between
the drive chains 120 and the inner wall of the air flow manifold
140 prevents loss of air pressure from within the segmen-ted
air-track crawler when the former slides along the latter
in its orbit. The T-shaped supports 130 carried by the drive
chains 120 function to support the seal 150 so that the internal
supporting air pressure will not displace the seal, CaUSlng
a loss of air pressure.
As best shown ln FIGS. 6 and 7, the air lube manifold
140 is formed wlth an internal wear resistant surface 141
through which perforations are formed Jo communicate with a
plurallty of alr supply chambers with each of the arcuate rows
ox hole 142, 143 and 144, being supplied separate1y with en
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air supply through a pressure-flow rate sensitive air valve.
Continuous aix flow at a fixed pressure is supplied to the
inner straight race of holes 145 to lubricate the sprocket
eontrolled circular end races. The air fro]m this straight
race 145 contributes to the total ai,r-track chamber pressure
when the slide deviates. The air supply to ah of the arcuate
rows of holes 142, 143, and 144 (separately supplied to each)
is such that the air valve supplies air flow at a high flow
rate and higher pressure when back pressure is applied to the
holes, while low back pressure such as in the absence of contact`
with the Teflon sealing face 151 of the sliding seal 150), cuts
off air flow through these outlets. Therefore, only those
parts covered by the sliding seal 150 will be supplied with a
continuous air flow at a high pressure and flow rate. Those
holes which are not covered by the sliding seal, will thereby
experience a slight air flow which will be effective to keep
the ports open. In this manner, the face of the slidino seal
150 acting against the wear resistant seal face 140 will have
an air-bearing formed therebetween, so that a high rate of air
flow is supplied at high pressure through the arcuate row of
holes 142, 143, and 144 in response to contact between the
Teflon face 151 of the sliding seal ]50 and the wear resistant
surface 141. FIG. 13 shows an alternative to air lubricated
sliding seal. Tne "Teflon" seal 151 is unchangedl but it
contacts a vertical sheet of materlal 151a, a nylon, plastic
composite, or other semi-rigid material which is also wear
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resistant Internal air track pressure penetrates behind
this 151a sheet to urge`it against the seal 151 to assure
seallng against leakage. This is a less expensive, less
durable, version of the air-track 1~0 flrst described. It is
also simplified and less expensive by having an external skid
rest ha to prevent the segments llU from crushing down on
the chains an sprockets with the air pressure of at rest.
Preferably, there should be two levels of pressure
to the air-track air supply, such as a dual air supply
separately regulated in pressure and volume for the seal
and the lift chamfer. The air lubrication should be higher
pressure than the lift alr pressure supplied to the interior
of the unit 10~ through part 14l (FIG. 11). All air leaking
inward from the sliding air bering will contribute to lift
air volume and pressure, but that pressure may need to be
varied as may the air air-track lift air operating pressure
according to its task or when running full or empty. In
this manner, the segmented air-track crawler units will
be supplied with the desired air pressure internally and
be effectively sealed during operation to prevent loss of
the internal air pressure.
An alternative embodiment of another suitable air-
track vehicle is as shown in FIGS. 14-16, wherein the cab
portion lla is articulated in relation to the carrier body
12a. As lllustrated in thls drawing, the air-track crawlers
100 are ull width crawler ts which may be pivoted about
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their supports in the various directions illustrated by dashed
lines to conform to changing grades, thereby illustrating the
grade climbing capability of the vehicle. A suitable ball joint
15, about which the two portions of the vehicle are articulated,
¦ facilitates movement of the vehicle through various difficult
terrain situations.
While the invention has been described with reference
to preferred embodiments, it will be understood by those
skilled in the art that various changes may be made and equiva-
lents may be substituted for elements thereof without departingfrom the scope of the invention. In addition, any modifications
may be made to adapt a particular situation or material to
¦ the teachings of the invention without departing from the
essential scope thereof. Therefore, it is intended that
the invention not be limited to the particular embodiments
disclosed as the best modes contemplated for carrying out this
invention, but that the invention will include all embodiments
fall ng within th- scope rf the appended claims.
