EP0464313B1

EP0464313B1 - Automatic asphalt paver machine for roads and other paved areas

Info

Publication number: EP0464313B1
Application number: EP91104507A
Authority: EP
Inventors: Lamberto Ricci Petitoni
Original assignee: Marini SpA
Current assignee: Marini SpA
Priority date: 1990-06-22
Filing date: 1991-03-22
Publication date: 1994-05-04
Anticipated expiration: 2011-03-22
Also published as: DE69101882D1; EP0464313A1; IT9083411A0; DE69101882T2; IT1242362B; IT9083411A1; ES2058965T3

Description

The present invention concerns an automatic asphalt paver machine for roads and other paved areas.
In prior art we know from PCT/SE81/00117 and IT-1144171 and from EP-0049260 (AB SKANSKA CEMENTCJUTERIET Sweden) a "Process for laying an anchorage coating onto a road surface".
This solution describes the convenience of applying one anchorage layer immediately before laying the bituminous layer onto the road surface.
This solution consists in applying a sticky anchorage coating onto the road surface (bitumen emulsion and water) before laying the asphalt layer, in order to give better adhesion of the asphalt.
Namely the road surface is previously cleaned and a thin anchorage film of sticky bituminous substance is sprayed onto it before the spreading of the next asphalt layer.
Also well known are finishing machines (pavers) for depositing onto the road surface new asphalt layers, these machines are generally self-movable or with a movable caterpillar track system, and involve rear height-adjustable auger asphalt distribution means, followed by rolling compacting means having a minimum width and to the rear of which are associated transversely movable rolling compacting means having the further function to spread and compact the asphalt over a wider extent of the road when compared to the width of the paver machine.
Similarly said auger means are symmetrically transversely laterally extendable to distribute and to spread the asphalt to a width greater than the minimum width of the machine, to satisfy the requirements of a spread made by means of said widthwise enlargeable compacting means.
The solution PCT/SE81/00117 corresponding to IT-1144171 or EP-0049260 (AB SKANSKA CEMENTCJUTERIET) does not suggest how we can produce in an efficient way a sticky bituminous spray in front of said enlargeable layer distribution compacting rolling means.
Furthermore we verified that it is useful to have an on-road spray device in front of said enlargeable layer distribution means, not only for reasons indicated in the above-mentioned disclosures but also for other scopes such as for example:

the washing of the road or its cleaning before the deposition of the bituminous layer,
the application of bituminous solvents, and so on;

EP-A-0418105 (SCREG ROUTES ET TRAVAUX PUBLICS) discloses a rear enlargeable and height-adjustable, asphalt layer distribution means for an automatic asphalt paver machine for the distribution in a uniform way of an asphalt layer, having in front of said asphalt layer distribution means, spray-jet means to jet fluid substances onto the road surface wherein both said spray-jet means and asphalt layer distribution means are enlargeable, to cover an extent wider than the machine.
EP-A-0292337 (SCREG ROUTES ET TRAVAUX PUBLICS) discloses similarly enlargeable spray-jet means.
In particular a self-propelled or towed automatic asphalt paver finishing machine for roads and other paved areas comprising widthwise and height adjustable aspalt layer distribution means and rolling means for the uniform distribution and compaction of at least one layer of asphalt, and wherein in front of said asphalt layer distribution means, spray-jet means are provided, the spray-jet means being so arranged that the spray path is widthwise enlargeable, which means jet fluid substances onto the road surfaces, wherein the spray-jet means are adjustable in height independently of the successive asphalt layer distribution means, and are movable in a direction transverse to the direction of advancement in order to increase the surface area sprayed.
Note that in this solution the spray-jet means is placed before the caterpillar tracks of the finishing machine.
This solution creates some problems with the movement of the caterpillar tracks over the sprayed surface causing a non-uniform distribution of the sprayed material which also sticks to the tracks. In particular the layer of asphalt sticks less well in the areas where the caterpillar tracks have passed as the surface of sprayed material is no longer uniform.
EP-A-0279795 discloses a material control arrangement for bulk of materials in which is illustrated a paving machine which has main fixed screeds associated with extendable screeds and enlarging cochlea asphalt means with opposing thread.
GB-A-1041511 (JOHNSTON BROTHERS (ENGINEERING) LIMITED) discloses enlargeable reciprocating spray-jet means with a number of spray jets spaced apart along the length thereof and which may be provided with a means for automatically cutting off the flow of material through certain of the orifices where the two spray bars overlap so that the density of spraying is constant across the whole width of the system.
US-A-4231678 (CARTERNOCK) discloses a paving machine comprising a shaft driven by a reversible hydraulic motor positioned at the inner end of the shaft. The shaft carries an Archimedean screw axially displaceable on the shaft and rotatable therewith. The screw is mounted on a bearing attached to the side wall of the hopper so that the width of the conveyor is usually the same as the width of the hopper. An extension conveyor unit may be provided, the shaft of which is disconnectably connected to the shaft to rotate therewith. Material from the hopper enters the conveyor and is thereby uniformly distributed along the whole width of the machine and any extension unit attached. Each extension unit has at its rear a height adjustable levelling plate to control the thickness of the layer of the material being laid by the extension unit.
If no extension is attached, the material is conveyed sideways beyond the side walls and is spread by an extension of the screed plate.
These prior art documents do not disclose how we can achieve a best performance in paving operations.
The object of the present invention is to allow the machine to perform a wider operational activity that can include the method above-mentioned or other, having the possibility to utilize said means for other scopes such as to spray or jet a fluid onto a road paving before said widthwise enlargeable layer distribution and compaction means in order to make possible the operation of the spray-jet means at different advancing speeds and with constant superficial treatment and with different asphalt layer width distribution.
This is achieved by means of a self-propelled or towed automatic asphalt paver finishing machine for roads and other paved areas comprising widthwise and height-adjustable, asphalt layer distribution means and rolling compacting means for the uniform distribution and compaction of at least one layer of asphalt, and wherein in front of said asphalt layer distribution means spray-jet means are provided, the spray-jet means being so arranged that the spray part is widthwise enlargeable, which means jet fluid substances onto the road surface, and wherein said spray-jet means are adjustable in height independently of the successive asphalt layer distribution means and movable in a direction transverse to the direction of advancement during the advancement of the asphalt paver, in a oscillating manner, characterized in that:

. said spray-jet means have a cut-off means to prevent the overlapping areas of the spray-jet means from being double sprayed, and
. there is a central spray-jet device behind a first and in front of a second transversely movable spray bar with respect to the direction of advancement of said spray bars comprising spray-jet means orientated to spray in a transverse direction whereas said central spray-jet device is orientated to spray in the direction of advancement.

Advantageously, said spray-jet means:

. are positioned between the asphalt layer distribution means and the respective final set of caterpillar tracks of the finishing machine;
. are adjustable in height independently of said successive asphalt layer distribution means portion, said distribution means comprising a transversally extendable opposite handed right and left auger means, and said rolling compacting means.

With this solution it is possible to vary the heigh of the spray-jet, as a function of the pressure variation of the jet with the scope of maintaining constant the amplitude of the jet that coats the surface to be treated.
Said spray-jet means are widthwise enlargeable by means of at least two spray sets transversely disposed and operatively downwards oriented, mounted on a displacement cross means, and able to move from a reunited substantially central position to a position substantially more or less externally enlarged and opposite each other, in order to cover different widths of road surface in conformity at least with the prearranged width of said widthwise enlargeable asphalt layer distribution means.
With this solution we obtain also the evident advantage of being able to apply any fluid (also air jets) to wash, clean or also pre-treat the road surface before the deposition of the bituminous layer in different widths. The invention is better understood with the attached description and data supplied for example only, in which:
Figure 1 represents a schematic side view of the finishing-machine (paver) according to the invention.
Figure 2 represents a schematic side view of the rear pavement finishing device according to the invention.
Figure 3 represents a schematic top view of the rear pavement finishing device according to the invention in a retracted minimum width position.
Figure 4 represents a schematic top view of the rear pavement finishing device according to the invention in an extended maximum width position.
Figure 5 represents a perspective schematic view of the disposition of the two movable spray-jet sets.
Figures 6 and 7 represent two schematic views of the spray-jet amplitude and respective different heights of the spray-jet nozzles from the road surface in proportion to different advancing speeds.
The Figures disclose that the invention relates to a self-propelled or towed automatic asphalt paver finishing-machine for roads and other paved areas comprising widthwise and height-adjustable asphalt-layer distribution means and rolling means (B), for the uniform distribution and compaction of at least one layer of asphalt or similar bituminous concrete, and wherein in front of said widthwise enlargeable asphalt layer distribution and compacting means (B), spray-jet means (A) are provided, the spray-jet means being so arranged that the spray path is widthwise enlargeable, which means jet fluid substances onto the road surface, these means being adjustable in height by a dynamic-fluid (cylinder) independent device (7).
Said spray-jet means for fluid substances (A) include at least two spray-jet sets (1,1') transversely disposed with downwards oriented nozzles mounted on a displacement cross means, and able to be transversely extended towards opposite sides from a reunited substantially central position (Fig.3) to a substantially laterally extended more or less wider position (Fig.4) in order to cover different widths of road surface in conformity at least with the prearranged width in said asphalt layer enlargeable distribution and compacting finishing means (B).
Said spray-jet means are transversely extendable to form a continuous transverse spray line.
Advantageously said spray-jet means for the coating or wetting of the road with fluid, includes also a central device with an alternatingly transversely movable spray-jet means (2).
Advantageously during partial widthwise enlargement the sprayers which overlap are excluded from double spraying by well known means, thus avoiding non-uniform wetting.
For the same reason, because the machine can advance at different speeds, we would have, with spray flow constancy, a different level of superficial wetting of the road.
To obviate this drawback, according to the invention the spray flow is varied as a function of the speed of advancement, correspondingly varying the delivery pressure.
It is, however, a known scientific principle that increasing the delivery pressure causes the spray jet to widen, consequently giving a non-uniform distribution with overlapping layers.
For this reason, according to the invention, the spray-jet device is also height-adjustable.
Figures 6 and 7 disclose that with a speed of advancement V1 we have for example, with a pressure p1, a spray amplitude B, consequently in order to obtain a spray amplitude "D" on the road surface, we distance the spray-jet means at a proportional height H from the road surface.
If we change the speed of advancement to V2>V1, to increase the flow we have to increase the delivery pressure proportionally to p2 and consequently the spray amplitude B1 has a greater angle, consequently to maintain constant the spray amplitude (spray band) on the road and to avoid spray overlap, we lower the spray-jet means to a level h<H.
Concerning instead the oscillating sprayers, as for example the central sprayer or others if so pre-arranged, in order to have a constant superficial treatment, the oscillation frequency of the oscillation device is variable in direct proportion to the variation of the advancing speed.
Said rear widthwise enlargeable asphalt layer distribution and compaction means (B) are adjustable in height by means of lateral arms (6) and involve opposite handed auger asphalt distribution means (clockwise-counterclockwise), transversely extendable in opposition (3'), and at the rear are disposed asphalt layer rolling and compaction means (vibrating rollers Etc), involving a central compaction means of fixed minimum width (4) to compact a restricted central band of the road surface area and at the rear, two compaction means transversely movable in opposition to spread and compact the layer of the opposed sides to a width larger than the width of the machine (5).
To assist the spray system, the machine includes furthermore:

3000 litre fluid storage tank;
spray circuit with volumetric control and spray pressure regulation;
auxiliary cleaning circuit and compressed air jet means;
heating circuit to heat the main spray circuit.

With this system it is possible to spray fluids in advance of the deposition of the layer of conglomerate, with variable dosages from 500 to 1000 grams/m2, in a uniform way and without overlapping or discontinuity in the speed range of the machine between 4 and 12 metres/min., with spray width (and successive spreading of the asphalt layer) from 2,5 and 4,80 metres or with the addition of extensions between 3,7 and 6 metres.

Claims

A self-propelled or towed automatic asphalt paver finishing machine for roads and other paved areas comprising widthwise and height-adjustable, asphalt layer distribution means and rolling compacting means (B) for the uniform distribution and compaction of at least one layer of asphalt, and wherein in front of said asphalt layer distribution means (B) spray-jet means (A) are provided, the spray-jet means being so arranged that the spray part is widthwise enlargeable, which means jet fluid substances onto the road surface, and wherein said spray-jet means (A) are adjustable in height independently of the successive asphalt layer distribution means and movable in a direction transverse to the direction of advancement during the advancement of the asphalt paver, in an oscillating manner, characterized in that:
. said spray-jet means (A) have a cut-off means to prevent the overlapping areas of the spray-jet means from being double sprayed, and

. there is a central spray-jet device (2), behind a first (1') and in front of a second transversely movable spray bar (1) with respect to the direction of advancement of said spray bars (1,1') comprising spray-jet means orientated to spray in a transverse direction whereas said central spray-jet device is orientated to spray in the direction of advancement.
A self-propelled or towed automatic asphalt paver finishing machine for roads and other paved areas as claimed in Claim 1, characterized in that said spray-jet means:
. are positioned between the asphalt layer distribution means (B/3,4,5) and the respective final set of caterpillar tracks of the finishing machine;

. are adjustable in height (7) independently of the successive asphalt layer distribution means portion, said distribution means comprising a transversally extendable opposite handed right and left auger means (3-3'), and said rolling compacting means (4-5B).
A paver finishing-machine according to claim 1, characterized in that said central spray-jet device (2) is alternatingly transversely movable.
A paver finishing-machine according to claim 1, characterized in that the oscillation device of said spray-jet means includes devices and command means such as to make possible the variation of the respective oscillation frequency in direct proportion to the variation of the speed of advancement of the machine.
A paver finishing-machine according to claim 1, of the type having asphalt layer distribution means with opposite handed right and left auger means (3), characterized in that said enlargeable distribution means and rear compacting asphalt layer means (4-5) are both adjustable in height (6,7).