Note: Descriptions are shown in the official language in which they were submitted.
CA 02542177 1993-03-12
VEHICLE FOR FILLING POTHOLES
This is a divisional of Canadian Patent Application 2,091,596 filed March 12,
1993.
This invention relates to a vehicle for filling potholes in roads with an
asphalt-
gravel mixture.
Potholes and the like in roads need to be repaired, typically by filling with
a
mixture of gravel and liquid asphalt. When the asphalt hardens on cooling, a
strong,
composite material results for long term repair of the pothole.
In the prior art, Automated Road Repair Systems, Inc. has sold a vehicle which
comprises a motor-driven, wheeled chassis upon which there is carried a gravel
hopper, a
tank for holding liquid asphalt, and a pump for providing air pressure. Hoses
extend
respectively from the gravel hopper and the asphalt tank along an extensible
and
retractable boom at the front of the vehicle, to meet at a mixing head at the
end of the
boom. The gravel hose is connected to the air pressure source, the gravel
hopper has a
bottom aperture which communicates with the hose for the gravel, with the flow
of gravel
being controlled by a vane-type feeder valve, which is constructed rather like
a horizontal
revolving door.
In order to allow the outer end of the gravel hose to move with the extensible
and
retractable boom, the hose is carried on the boom, with the central portion of
the hose
defining a loop, to provide adequate slack so that the outer end of the hose
can extend with
the extending boom.
Thus, the outer end of the boom, carrying the mixing head, can be adjusted by
controlling of the boom so that it is positioned over the pothole. Then,
typically, the repair
area is blown clean with the high velocity air that can come through the
gravel hose, while
the vane-type feeder valve does not permit gravel to enter the gravel hose.
Then, from the
asphalt supply, asphalt without gravel enters the head and is blown into the
hole for repair.
Following this, a mixture of gravel and asphalt is applied with high pressure
air to the
repair area until the pothole is filled. Typically, no rolling or tamping is
required because,
of the use of the high pressure air.
Thus, the vehicle can be operated by one man, replacing an entire crew, to
drive
along a road, locate damaged areas, and fill them up with the mixture of
gravel and
asphalt, to repair the pothole or large road crack without the driver ever
leaving the control
cab of the vehicle.
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While the vehicle of the prior art has been highly useful and beneficial, it
exhibits
certain shortcomings and drawbacks which have increased, its cost of operation
and
limited its use.
For example, the vane-type control valve positioned at the bottom of the
gravel
hopper has been found to exhibit rapid wear, in view of the strong compressed
air flow
conditions mixed with gravel encountered by the vane valve. The periodic
replacement of
such a vane valve has been expensive and time consuming.
Also, the gravel hose has exhibited rapid rates of wear, in part because the
hitherto-
necessary loop in the gravel hose causes the rapidly moving gravel under high
air pressure
to impact internal walls thereof all the way around the loop, which seriously
increases the
wear. Thus, the gravel hose must be replaced on a relatively frequent basis,
which is an
expensive proposition. Additionally, the non-straight configuration of the
gravel hose can
sometimes increase the possibility of the gravel plugging up in the hose in a
curved section
thereof, which is, of course, a significant problem which requires halting of
repair
operations with the vehicle.
Also, the hose for the asphalt must be of an excessive length so that it can
move
outwardly with the extending boom. Thus, when the boom is in retracted
position, the
asphalt hose forms undesired loops and the like which have the risk of
becoming
entangled with each other or with other parts of the vehicle. Particularly,
the asphalt hose
in the retracted-boom configuration sometimes has a tendency to touch the
ground, with
resulting serious wear as the vehicle travels.
In accordance with this invention, the above problems are solved, with the
result
that an efficiently operating machine is provided, with significantly better
wear
characteristics of the asphalt and gravel hoses and the bottom valve of the
gravel hopper.
Thus, the improved vehicle of this invention has significantly reduced
maintenance costs
and maintenance time.
The vehicle of this invention is for filling potholes and the like in roads
with an
asphalt-gravel mixture. It comprises a wheeled chassis and a driving motor, a
gravel
hopper, a tank for holding liquid asphalt, an extendable and retractable boom,
and a head
carried on the boom for mixing and applying the asphalt-gravel mixture to
desired road
sites.
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First hose means is carried along the boom and communicates between the hopper
and the head. Second hose means is also provided, being carried along the boom
and
communicating between the liquid asphalt tank and the head.
In accordance with this invention, the first hose means comprises telescoping
sections which permit extension and retraction of the first hose means along
with the
extension and retraction of the boom, without the formation of bows or loops
in the first
hose means. Accordingly, the first hose means can continuously occupy a
relatively
straight path, to facilitate the transport of gravel therein and to reduce
wear as it is
extended and retracted along with the boom. It can be seen that the term
"hose" is not
intended to exclude a rigid section thereof. For example, the telescoping
sections may be
made of rigid metal or plastic.
In another aspect of this invention, a central portion of the second hose
means,
which conveys the liquid asphalt, occupies an S-shaped configuration. This is
accomplished in part by the second hose being rearwardly looped around a
pulley which is
longitudlnally slidingly carried on an inextensible portion of the boom. An
outer end
portion of the second hose is attached to an extensible portion of the boom.
Thus, forward
extension of the boom causes at least some of the second hose means to extend
forwardly.
This forward extension causes a changing of the shape of the S-shaped
configuration of
the second hose means, and the same forward extension of the second hose means
also
draws the pulley forwardly along the boom.
Preferably, spring means are present to urge the pulley rearwardly along the
boom.
Thus, a tension is imparted to at least a portion of the second hose means, to
maintain its
S-shaped configuration and to avoid the second hose means from forming
undesirable
loops, particularly a sagging loop that sags down far enough to engage the
road.
Generally, a relatively gentle tension is used, typically just enough tension
to keep the
second hose means from forming significant and undesirable sagging loop
portions.
As another aspect of this invention, the gravel hopper of the vehicle defines
a
bottom first aperture. A plate defines a second aperture which is attached to
the bottom of
the gravel hopper, with the first and second apertures being positioned in
registry with
each other, so that gravel is capable of falling through the two apertures
from the hopper.
An advanceable and retractable blade is slidable between the first and second
apertures, to selectively open or to block off communication therebetween.
When the
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blade is open, gravel will fall through the two registering apertures, when
the blade is
blocking off communication between the two apertures, then, of course, gravel
does not
flow from the hopper. The second aperture is below the first aperture, and is
typically
larger than the first aperture in at least the direction of sliding of the
blade.
Thus, the flow of gravel through the aperture is controlled by the position of
the
blade. Gravel falling through the apertures, enters a plenum, positioned below
the
apertures, with the plenum being connected to the first hose.
If desired, the plate and second aperture may be eliminated with just a
sliding track
for the blade being provided.
The increase in the size of the second aperture relative to the first aperture
in the
direction of sliding of the blade helps to prevent the jamming of the blade in
its sliding
path by grains of gravel. Particularly when the forward edge of the blade
closes off the
first aperture, but there is still a substantial amount of the second aperture
around the
forward edge of the blade, there is a strong tendency for pieces of gravel to
fall away from
the valve, and not to cause jamming or wedging thereof in a manner to prevent
closure of
the valve and termination of the flow of gravel.
Preferably, means are provided for the blowing of air through the plenum and
the
first hose. This stream of blown air is of sufficient strength to propel
gravel through the
first hose and through the head. Also, as described above, the air blast may
be used in the
absence of gravel to blow out loose materials from a prospective repair site.
Then, the
same air can be used to blow hot, liquid asphalt into the repair site to form
an adhesive
coating, followed which, typically, a mixture of asphalt and gravel is applied
to the
pothole or other defect, being forcefully driven into its desired place by the
air flow.
Preferably, the blade is carried on the end of a shaft. The shaft is moved
back and
forth by power means to control the position of the advanceable and
retractable blade
between open valve and closed valve positions. Turnbuckle means are provided
in the
shaft to permit adjustment of the length of the shaft, and thus to permit
adjustment of the
position of the blade.
In the accompanying drawings:
Fig. 1 is a perspective view of one embodiment of the vehicle of this
invention;
Fig. 2 is a plan view of the boom on the front of the vehicle of Fig. 1;
Fig. 3 is an elevational view of the boom of Fig. 2;
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Fig. 4 is a fragmentary, detailed elevational view of the vehicle of Fig. 1 at
the
bottom of the gravel hopper;
Fig. 5 is a bottom plan view, with portions removed, of the valve at the
gravel
hopper bottom;
Fig. 6 is a top plan view taken along line 6-6 of the valve of Fig. 5; and
Fig. 7 is a plan view of an intermediate part of the valve of Figs. 5 and 6.
Referring to Fig. l, a vehicle for filling potholes and the like in roads with
an
asphalt-gravel mixture is disclosed in accordance with this invention. Vehicle
10
comprises a wheeled chassis 12, carrying a driving motor 15, being typically a
standard
truck chassis and motor, being modified and carrying components as described
herein.
Vehicle 10 carries a gravel hopper 13 and a tank 14 for liquid asphalt, with a
conventional heater to keep the asphalt in liquid form.
Vehicle 10 also carries an extendable and retractable front boom 16, which may
be
generally of conventional design except as otherwise described herein. Boom
16, in turn,
carries a mixing head 18, which also may be of conventional design for the
mixing of
asphalt and gravel to cause a mixed asphalt-gravel composition 20 to be
expelled from
head 18 into road potholes and the like, as shown.
A first hose 22 is carried along boom 16 and communicates between hopper 13
and
head 20, as shown in Fig. 1 but also in greater detail in Fig. 3.
A second hose 24 is also provided, being carried along boom 16 and
communicating between asphalt tank 14 and mixing head 18. Particularly, it can
be seen
that at the outer end of hose 24, it divides into a plurality of branched
sections 26 so that
liquid asphalt can be applied radially inwardly of head 18 from a plurality of
directions
into the stream of gravel proceeding through the head via first hose 22.
An air compressor 28 of conventional design includes a conduit 29 which
communicates with the rear end of first hose 22 (Fig. 4) to supply a blast of
air to conduit
22. A supply valve 30 is provided at the bottom of hopper 13 so that gravel
may be
dropped into the air stream from air compressor 28 in a path which passes
through first
hose 22 in the manner illustrated by arrow 32 in Fig. 4. Thus, a blast of
compressed air
may be provided through head 18, without gravel or asphalt, to blow granular
material out
of a pothole. Then, if desired, a conventional control valve for asphalt tank
14 may be
opened so that asphalt passes through second hose 24 in a relatively small
quantity to coat
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the pothole with a layer of asphalt, being forcefully impelled out of head 18
by the stream
of air through hose 22 by an aspiration principle. Then, valve 30 may be
opened so that
gravel falls into the air stream, and is forcefully passed through first hose
22 into mixing
relation with asphalt from second hose 24, and from there the mixture 20 fills
the pothole.
Boom 16 defines an extension cylinder 34 having a plunger 36 that advances
outwardly or retracts. Both hoses 22, 24 are attached thereto by cross bar 38,
so that the
outer ends of the hoses advance with the boom.
Boom 16 can pivot upwardly by the action of power cylinder 40 (Fig. 3), or it
can
pivot from side to side by the action of power cylinder 42. Thus, mixing head
18 of the
boom 16 can be positioned throughout a substantial range of positions by the
operator of
the vehicle, so that the vehicle operator, from the cab of the vehicle, can
properly position
head 18 for filling a pothole, and then can fill the pothole in the manner
previously
described.
In accordance with this invention, certain disadvantages of the prior art
vehicle, as
described above, have been overcome. For example, since the boom is inwardly
and
outwardly extensible and retractable, and the outer ends of the first and
second hoses must
travel with the outer end of the boom. In the prior art, first hose 22 had to
be carried with
a central loop configuration to accommodate this inward and outward moving.
The
onrushing gravel within first hose 22 caused a great deal of wear in the
looped area,
requiring frequent replacement of the first hose. Also, the problem of
clogging could be a
problem because of the substantial curvature of the first hose 22.
By this invention, the above problem is overcome by causing the first hose 22
to
have a portion thereof which comprises telescoping sections 44, 46, 48, with
the respective
sections being of different diameters so that they can fit in telescoping
relation within one
another while remaining open. Preferably, the smallest diameter telescoping
section 48 is
positioned upstream from the next smallest diameter section 46, which is
positioned
upstream from the largest diameter telescoping section 44. Thus, gravel
rapidly flying
through hose 22 does not impact against the ends of the telescoping sections
to cause
damage.
Accordingly, it can be seen that the sliding, telescoping sections 44, 46, 48
can
extend and retract with boom 16 as plunger 36 of the boom extends and
retracts, while at
the same time no loop is required in the first hose 22 to accommodate such
extension, with
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the result that wear of the first hose 22 is greatly reduced. Also, because of
the increased
straightness of first hose 22 by this invention, the danger of clogging with
blocked piles of
gravel is reduced as well, to facilitate the transport of gravel therein.
By this invention, the mounting of second hose 24 is also improved. It also
needs
a substantial slack to accommodate the extension and retraction of boom 16.
However, in
the retracted position, it is, of course, important for second hose 24 to not
drag the ground,
or to become so looped that it tangles in some way.
In accordance with this invention, second hose 24 is carried on boom 16 in an
S-
shaped configuration, as particularly shown in Fig. 3. Second hose 24 is
rearwardly
looped around a pulley 50. Pulley 50, in turn, is longitudinally slidingly
carried on boom
16, with the bracket 52 that carries pulley 50 being slidable in groove 54 of
the boom,
which groove is typically defined on both sides of the boom cylinder 34.
Rollers 56 are
carried by bracket 52 on both sides to facilitate this sliding.
Spring member 58 is also provided to urge bracket 52 and pulley 50 into a
rearward position so that a moderate amount of tension is placed on second
hose 24.
Thus, when boom 16 expands its extension rod 36, the forward portion of second
hose 24 is carried with it, and pulley 50 also slides forwardly to a certain
extent, as the
shape of the S-shaped configuration of second hose 24 is changed.
Nevertheless, second
hose 24 remains under tension because of the rearward pulling action of spring
58. Then,
as boom 16 retracts, spring 58 draws second hose 24 rearwardly, and
continuingly under
tension, so that it can fold back into a deeper, S-shaped configuration once
again.
Referring to Figs. 4-7, another improvement of this invention is disclosed. In
the
prior art, a vane-type valve is provided to function in the manner of valve 30
as a control
valve for the fall of gravel out of hopper 13. However, it has been found that
such a vane-
type valve wears rapidly under these particular conditions of use, because of
the impacting
of gravel against the vanes caused by the blast of air from air compressor 28
and its
conduit 29.
In accordance with this invention, an improved control valve is provided.
Gravel
hopper 13 defines a first aperture 60, being typically provided by a first
plate 62 over a
gravel hopper aperture in its bottom wall, which plate is bolted to the bottom
wall of
gravel hopper 13.
CA 02542177 1993-03-12
* ,
A plate 64 defines a second aperture 66, with the first and second apertures
60, 66
being positioned in registry with each other. Between plates 62, 64 there is
positioned a
U-shaped plate 68 to provide a slot between the respective plates. Within this
slot is
positioned an advanceable and retractable blade 70. An angled bend 72 is shown
in plate
70 in Fig. 4. Such bend does not have to be present, and the system may be
straight if
desired. Otherwise blade 70 is capable of flexing to accommodate the
misalignment
provided by bend 72.
Blade 70 is also connected to a shaft 74 which may be controlled by a
hydraulic
cylinder 76 at its end, to move shaft 74 between an advanced position and a
retracted
position in the slot between the first and second apertures 60, 66 to
selectively open or
block off communication therebetween. Fig. 5 shows an advanced position of
blade 70,
where aperture 60 is completely blocked. Fig. 6 shows an open position where
aperture 60
is partially open, so that gravel can fall through aperture 60 and then
aperture 66 into first
hose 22 via plenum 31. Blade 70 defines a concave edge 78 to facilitate the
flow of gravel
through the apertures 60, 66 when the blade is in open position.
This valve system is adjustable to vary the amount of gravel flowing
therethrough
per unit time. A turnbuckle 80 is provided in shaft 74 to adjust the length of
the shaft.
This, in turn, adjusts the position of blade 70 in its respective open and
closed positions as
shown in Figs. 6 and 5. In the open position, as turnbuckle 80 is moved, the
position of
blade 70 may be varied as illustrated by the respective full line position of
edge 78 and the
dotted line position of the same edge in Fig. 6, this position being as
controlled by the
turnbuckle. Thus, the area of the open aperture 60 can be adjusted, which, in
turn, controls
the drop rate of gravel therethrough. Fig. 5 shows the similar relationship in
the closed
position.
It can be seen that lower aperture 66 is longer than upper aperture 60 in the
direction of sliding motion of blade 70. This provides the advantage of
reducing the
danger that gravel will jam up in the valve as blade 70 closes off aperture
60. Because
aperture 66 is longer at the closing edge, gravel is more likely to fall away
from the
advancing blade edge 78 and not wedge or jam between the blade and an aperture
edge.
Thus, an improved vehicle for filling potholes and the like is provided, which
operates with substantially reduced wear, and thus needs less maintenance than
the design
of the prior art.
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The above is offered for illustrative purposed only, and is not intended to
limit the
scope of the invention of this application, which is as defined in the claims
below.
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