Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to the renewal of asphalt road surfaces or
pavements wherein in the course of one single operational step the road sur-
face to be renewed is cut or milled aw~y, the road surface so treated is
cleaned from the milled or cut off material, and subsequently new surface
material is applied.
` ~ It has been known to renew asphalt road surfaces which have been
damaged by either studded tyres or by atmospheric influence by cutting or
milling away the surface thereof and subsequently, in the same operational
step, coating the milled away surface with new material. Prior to the cutting
or milling procedure, the road surface to be treated is generally heated in
order to lower the treatment time per unit area of road surface and to de-
crease the wear of the cutting and milling tools, and also to obtain satis-
factory adhesion of the new coating on the cut away or milled away old coating.
If the warm asphalt is applied, under pressure, on a heated old coating, a
kin~d of "seal" will be obtained between the asphalt and the old coating. As
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has furthermore been found out, the adhesion of the new coating on the old
one is the better, the cleaner the cut away or milled away surface. It is for
this reason that of late the cut away ~n milled away surface is brushed away.
Generally, this offers a great deal of difficulties, since heating of the
road surface which is to be cut or milled away causes the cut away or milled
away material to clod ltogether and stick to the treated surface. Although
this effect can be avoided by decreasing the heat, the desired seal between
` the coatings will then not be obtained as the temperature of the cut away or
milled away old coating is too low. The latter will, by the way, also be the
case if the coating to be removed is relatively thick, since the amount of
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heat applied to the coating must remain below a certain limiting value in view
of the danger of overheating.
The present invention provides an apparatus for repairing asphaltic
:~ road pavements in a combined operation comprising an elongated chassis having
at least three wheels, at least one of which is steerable and at least one
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~:` of which is drivable so that said chassis is supported for movement longitud-
~$ inally along such a pavement~ a series of longitudinally spaced processing
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:~ units carried by such chassis and including means for heating the upper sur-
~!'`` face of such a pavement, behind said means for heating, a means for milling
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~~ 10 the thus heated upper surface to cut away the same to a depth less than that
~ of at least some of the damaged areas of such pavement~ behind said means for
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~ milling, a means for distributing at least some of such displaced material
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into the recesses of such damaged areas, means for compressing such distrib-
uted material, means at the rear end of said chassis for applying fresh
asphaltic material to such heated exposed upper surface, and a tub-like stor-
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`` age bin provided at the front end of said chassis for the storage of the new
coating material, wherein said s~orage bin is provided with supporting wheels
.` and is pivotally mounted for movement about a horizontal axis on said chassis
i so that it can be tilted.
It is of advantage to heat the cut away or milled away road surface
after the cleaning step. In this way, a particularly uniform heating of the
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~ treated road surface~ and thereby a uniform adhesion between this surface and f ',
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~ the new coating can be obtained.
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~ It has furthermore shown to be of advantage if the cut away or
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~ milled away road surface is subjected to a depth heating. In this way, it
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is sa~eguarded that structural defects developed in the course of the cutting
or milling of the road surface are cured when applying the new coating.
As is the case in the prior art method, the road surface is heated
prior to the milling or cutting step. For this heating, considerably less
energy is generally used than in the prior art methods as the surface is heat-
ed only to the extent of the thickness to be cut away or milled away. In
this case, where onl~ such heating of the cut away or milled away old coating
is provided~ the energy consumption is considerably smaller than in the prior -
art method.
~s thë darnages encountered on the road surface are very often rela- ;~
tively deep, large amounts of the road surface have to be milled away and on
the other hand a correspondingly large amount of new road coating material
has to be used for re coating and preparation of the new surface layer. The
relatively large material exchange is very costly. With the apparatus of the
present invention the road surface is milled away for only a relatively small
amount and for the re-coating with the new surface material, only a correspond-
ingly smaller thickness is necessary.
By performing extensive tests, Applicant has now developed a method
for renewing damaged asphalt road surfaces wherein the costs for the milling
away as well as for the re~coating can considerably be decreased and wherein
only a fraction of the road surface that was hitherto milled away need b2~
removed and wherein consequently only a fraction of the material needed for
re-coating is necessary. The cutting away or the milling away of the damaged
road surface is performed to an amount not reaching the depth of the damage,
at least part of the cut away material is distributed in the recesses and is
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compressed and~ subsequently~ the road surface may be subjected to a heating
and a subsequent aeration, and is then uniformly coated with a new material.
; ~pplicant re-use at least part of the cut away road surface material which
is filled into the remaining grooves or damage in the road surface after the
cutting process and, is then compressed and subsequently heated. By so doing,
this re-used road surface material combines, because of the bitumen contained
therein, with the damaged road surface, and after subsequent aeration of the
total road surfacej~the latter can be coated with the new material. In this
way, while saving considerable costs, a road surface can be produced which
meets all the requirements and which excels in durability and stability. By
re-using at least part of the milled away road surface material, the milled
off material does not have to be trucked away, and also new material is saved
to the same e~tent as the milled away material is re-employed. It has proved
to be sufficient in practical operation for 1 to 1.5 cm of the damaged road
surface to be milled away.
By filling and compressing milled away material into the remaining
grooves of the road surface, it is made possible that the new surface mate-
rial, finally used, is applied in an essentially uniform thickness so that
the crumples of the new material usually encountered on locations where the
latter is applied in a greater thickness are avoided in a simple way.
If the procedural steps of milling away, distributing the milled
away material within the grooves, compressing, heating, aerating~ and coating
with the new material are performed in one procedural step, the time neces-
sary for the repair of the road surface is reduced to a minimum so that traf-
fic is only slightly impaired by the repair of the road surface.
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It has shown to be very suitable, particularly in those cases when
a road surface having a relatively small bitumen portion is milled away,
prior to filling the milled away material into the remaining damaged areas of
the road surface to mix the latter material with preferably liquified bitumen.
Such liquid bitumen when heated can be sprayed on the milled away and pulver-
i~ed material and will, in this wayj increase the adhesion of the material
filled into, and compressed within, the recesses.
The machine according to the invention preferably includes a further
heating device immediately in front of the spreader device. Such an arrange- ~
ment has the advantage that, considering that heating is immediately followed ~ ;
by the spreading of the treated road surface~ a smaller amount of heat is
needed than would be the case in a position more distant from the spreader
device. This has~not only a favorable effect on the current costs of the
heating device but permits also a longer useful time of the machina between
the times when the fuel tank has to be refilled.
In order to optimally adjust the heating device relative to the
range of heat needed, i.e. to the intensity and the depth of the heating of
the treated road surface, it is recommended to so provide the heating devices
on the chassis that they can vertically be adjusted. For the vertical adjust- -
ment, there can be provided at least one hydraulic servomotor or, which can be
advantageous with a view to the fact that the heating device need be adjusted
in relatively rare cases only, at least one manually operated rack-and-pinion
gear. In a machine having the pre-heatera arranged in front of the cutting
or milling device, to warm up the road surface to be cut away or milled away,
the pre-heater and the further heating device are suitably operated with the
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same fuel. It has proved to be particularly favorable for the costs of the
heating to use liquid gas as the fuel. The fuel tank may be provided on the
chassis above the cutting or milling device. This has the advantage that the
cutting or milling device is subjected to an additional high load which has a
favorable effect on the uniform cutting or milling depth.
The heating device may suitably comprise a number of parallel tubes
provided with at least one succession of holes and arranged one after the
other. The tubes are advantageously secured on a frame. Such a heating
device is solid and can be manufactured at moderate cost. Under certain
conditions it may be of advantage to movably secure the frame to the chassis
to obtain a further possibility of varying the course of the heat.
The apparatus may suitably include, between the heating device and
the coating device, an additional scraping device which aerates the milled
off road surface and the materials compressed in the recesses and thus im-
proves adhesion between the road surface and the new coating applied.
The compressing means preferably comprises a vibration compressor
and may cover the total width of the machine or may be restricted to the
damaged location, or locations. An eccentric compressor may also be employed.
The compressor device is preferably provided in the form of a roller which
compresses, by its weight, the material in the recesses.
Distribution of the milled off material in the remaining recesses
is suitably performed by means of worm-shaped conveyor rollers which transport,
at the same time, the excessive material to the side of the road where it is
stored and can be removed by a second vehicle.
Preferably the heating device which may be provided in front of the
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coating device is vertically adjustable. In this way~ heating of the road
surface prior to the coating ean be controlled exactly.
The same applies to the scraper device which may be provided behind
the heating device which is also vertically adjustable. In this way, aeration
of the road surface prior to the application of the new surface material can
be adapted to the requirements to obtain optimum adhesion between road surface
and the new surface material applied.
Milling of the road surface is performed either with the aid of a
cutter roller provided with chisels or by peeling cutters. In the first
case, that is when using a cutter roller, it has shown to be of advantage to
provide at the two end supports of the cutter roller vertically adjustable
supporting wheels with the aid of which it is possible to adjust the cutting
depth exactly, and to substantially exclude vibrations during the cutting
process so that they will not affect the coating process at the rear end of
the machine.
A device, arranged after the cutting or milling device, for spray-
ing or mi~ing the milled off material with preferably liquid bitumen may be
provided. The bitumen or asphalt is heated and liquified in a container which
includes a heating device and is then sprayed with the aid of a generally
built-in spraying device onto the milled off material.
The storage bin may have a relatively great capacity~ can easily be
filled and particularly emtied and is so secured to the chassis that when it
is emptied a nonuniform loading of the machine can be avoided, or Gan at least
be substantially reduced by virtue of the support wheels.
Thus the capacity of the storage bin can be selected to be relative-
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ly large, since when not in use it can be tilted into a position wherein it
does not significantly enlarge the overall dimensions of the machine. By the
tilting connection of the storage bin to the chassis, residual amounts may
~e discharged from the storage bin, which greatly facilitates the cleaning
of the storage bin. By providing support wheels to the storage bin and pivot-
ing the storage bin to the chassis, changes in the filling of the storage bin
will not, or only slightly, change the overall load on the chassis. It is
furthermore possible to additionally load, by raising the storage bin, the
wheel pair neighboring the storage bin of the chassis, which is for instance
desired if a hard, difficult-to-treat road surface has to be removed.
In one embodiment of the invention, the storage bin is pivoted
directly on the chassis. It is however more suitable to secure the storage
bin to one end of a supporting arm the other end of which is pivoted to the
chassis and which carries part of the conveyor device. This has the advan-
tage that the storage bin can particularly easily be charged and decharged.
The portion of the conveyor device arranged within the supporting arm is
suitably provided as a belt conveyor. It is self-evident that a worm gear
conveyor or any other conveying device could be used.
For tilting the storage bin, a cable winch, an electromotor includ-
ing a gear or, as is particularly suitable, at least one hydraulic servomotor
can be employed. The advantage of the latter embodiment is that the hydraulic
servomotor, ean be connected to the existing hydraulic system, and no addi-
tional investment for a pressure means or current generator, is necessary.
In a preferred embodiment there are provided on each side of thc frame, which
houses part of the conveyor device, a hydraulic cylinder one end of each of
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which is pivoted to the chassis while the other end thereof is secured to a
point between the swivel axis and the storage bin. Such an embodiment con-
stitutes a particularly coMpact structure of high mechanical strength.
The number of supporting wheels provided on the storage bin can
be selected as desired. It is suitable to provide two supporting wheels.
In a preferred embodiment, the supporting wheels are vertically adjustable.
This offers the possibility of swivelling the storage bin, by hydraulic
operating cylinders provided on each side of the frame while at the same
time adjusting the height of the supporting wheels to different positions
without changing the load of the chassis. It is advantageous to adjust the
supporting wheels by hydraulic means.
The invention will be explained in detail in the following based
on the exemplary embodiments shown in the attached drawings wherein:-
Figure 1 is a schematic side view of a machine for milling and re-
coating wherein the road surface is heated prior to re-coating,
Figure 2 is a schematic side view of a machine for milling and re-
coating wherein part of the milled off material can be re-employed,
Figure 3 is a schematic side view of a machine for milling and re-
coating including a novel storage bin for the new material to be applied.
The machine depicted in a side view for cutting away and re-coating
road surfaces comprises chassis 1 incl~ding steerable front wheel pair 2 and
rear wh~el pair 3, a diesel engine 4 for driving said rear wheel pair 3~ and
a driver's cabin 5.
Between the two wheel pairs 2 and 3, there is provîded vertically
adjustable cutter roller 6. In front of cutter roller 6, in the direction
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; of travel, there is arranged a pre-heater 7 to warm the road surface 85 and
behind it, there is provided a cleaning device 9 including a worm conveyor
lOa and a rotary brush 10b. Cleaning device 9 is also vertically adjustable
on chassis 1. In order to vertically adjust cutter roller 6 and cleaning
device 9, two hydraulic servomotors, 11 and 12, respectively, are used.
The front portion of chassis 1 includes bin 13 holding the coating
material 14 to be used. Material 14 is transported via belt conveyor 15 to
the rear portion of chassis 1 to a spreader device 16 (not shown in detail).
In front of spreader device ~6, in the direction of travel~ a heat-
ing device 17 is vertically adjustable on chassis 1. For the vertical adjust-
ment, two rack-and-pinion gears 19 operated with the aid of a crank 18 are
provided. Heating device 17 includes frame 20 secured to the movable parts
of the rack-and-pinion gears 19 and has a number of parallel and series-
connected gas-heated infra-red heaters. Pre-heater 7 as well as heating de-
vice 17 are operated by liquid gas which is stored in tank 22 arranged on
chassis 1 above cutter roller 6.
In the machine shown in Figure 2~ the cutter roller 6 is vertically
adjustably mounted on chassis 1 and pre-heater77 is vertically adjustably -
secured in front of cutter roller 6, seen in the direction of travel, on
chassis i and is operated by liquid gas which is fed from fuel tank 22 via
duct 23.
Behind the cutter roller 6, as seen in the direction of travel,
there is provided a worm conveyor 24, by which the milled off material is
transported into the remaining recesses in the road to be compressed and
solidified in these recesses by compressor 25 arranged behind it.
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A second heating device 17 vertically adjustably provided on chas-
sis 1 comprises gas heaters which are fed via duct 26 from liquid gas tank
22, and serves to heat the road surface.
Behind the heating device 17, a scraper device 27 is provided on
chassis 1 and, by a corresponding height adjustment, enables the solidified
and heated road sur~ace to be aerated up to a desired depth before the spread-
errdevice 16 provided on the chassis applies the new surface layer 28.
The material for the new surface layer 28 is stored at the front
end of the machine in a suitable bin 13 and is transported via a conveyor
belt 15 running over chassis 1 to the spreader device 16 at the rear end ~f
chassis 1.
Between cutter roller 6 and worm conveyor 24, there is provided a
spraying device 29 by which bitumen (or asphalt), liquified in heatable con-
tainer 30, is sprayed onto the milled off material in order to improve the
a & esion of this material to the road recesses.
Cutter roller 6 is provided on each side at its end supports with
a vertically adjustable support wheel 31. These two support whee~s permit
exact adjustment~of the cutting depth, and avoid the ~ibrations usually en-
countered in the cutting process, which would very easily be transferred to
the spreader device provided at the rear end of the machine and would lead to
a non-uniform~ particularly a wavelike layer.
The machine shown in Figure 3 comprises a chassis 1 including a
driven and steerable front wheel pair 2 and a rear wheel pair 3. At the rear
portion of the machine, there is drive motor 4, and the driver's cabin in
front thereof. In front of the driver~s cabin, fuel tank 32 for engine 4 is
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; provided and in front thereof liquid gas tank 22 is arranged which is con-
nected, via duct 23, to heating device 7 secured behind front wheel paTr 2.
Behind heating device 7, cutter roller 6 is arranged. ~t ~he rear end of the
machine, spreader device 16 is provided which is connected via a conveyor
device including two belt conveyors 33 and 34 to storage bin 14 provided in
front of the machine.
Storage bin 14 is secured to one end of frame 35 the other end of
which is secured, tiltingly around axis 36, to chassis 1. In order to tilt
frame 35 in which the rollers of belt conveyor 34 are supported, there is
provided a hydraulic operating cylinder 37 on each side of the frame connect-
ed at one end to chassis 1 and at the other to frame 35. Storage bin 14 bears
via two wheels 38 on the road surface to be milled away. Each of the two
support wheels 38 is vertically adjustable via a hydraulic operating cylinder
39 so that storage bin 14 can be~adjusted, by actuating operating cylinder 37
and 39, in various positions in which it is still supported on the road sur-
face but can also, by the actuation of operating cylinders 37 be adjusted to
a position wherein the tota1 weight rests on the nei hbori fr~t whee1 pair.
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