EP0484220A1 - Asphalt paving machine - Google Patents

Abstract

The present invention relates to a machine for processing road materials, in particular for spreading road surface layers intended to be applied in layers of different thicknesses, in particular bituminous concrete in ultra-thin layers, of the type comprising a chassis equipped rolling means and able to be coupled to a traction means intended to ensure its advancement on the ground, characterized in that it comprises a hopper (16) for densification and distribution of said material including the lower orifice (18) is arranged close to the ground, as well as a vibrating bar (38) mounted in the immediate vicinity of the rear transverse edge (40) of said hopper (16).

Description

The object of the present invention relates to a machine for processing road materials generally consisting of aggregates coated or not with bituminous hydraulic binders, for example bituminous concretes.

The machine according to the invention is in particular intended to ensure the spreading of road surface layers which, depending on the circumstances, must be applied both in ultra-thin layers of thickness as constant as possible, or in layers of greater thickness, in particular to ensure a reprofiling of the roadway.

The object of the present invention therefore finds its application in the field of maintenance and production of various types of pavement layers.

The spreading of bituminous concretes in ultra-thin layers, i.e. corresponding to a thickness close to the maximum particle size dimension of gravel, raises problems that are often difficult or even impossible to solve satisfactorily.

With current devices, these difficulties can only be overcome by carefully preparing the support to give it a reprofiled surface.

Indeed, the spreading of ultra-thin layers of bituminous concrete very often damages the tables of the finishers which wear out prematurely by abrasion in contact with the aggregates which emerge from the ultra-thin coating layer.

Finally, the largest gravel is sometimes entrained by the rear edge of the finisher's table, which causes streaks of gravel and creates uneven surfaces by combing.

These major drawbacks can be definitively eliminated with the aid of the processing machine according to the invention.

The machine according to the invention also has the advantage of being able to adapt very easily and very quickly to the application of other types of coatings, for example to the application of layers of greater thickness, in particular in the case of reprofiling of very irregular pavements.

The present invention also aims to design a machine allowing the execution of spreading road materials at much higher speeds than those observed with all types of traditional pavers. With the machine object of the present invention, it is possible to reach application speeds of up to 30 meters per minute.

According to the present invention, the machine for processing road materials is of the type comprising a chassis equipped with rolling means and capable of being coupled to a traction means intended to ensure its advancement on the ground. It is characterized in that it includes a densification hopper and distribution of said material, hopper whose lower orifice is disposed near the ground; It is further characterized by the presence of a vibrating bar mounted in the immediate vicinity of the rear transverse edge of said hopper.

In addition, advantageously, the hopper (16) is mounted on articulated arms (22) on a transverse pivot axis (24) arranged in front of said hopper and being able to be supported by idler wheels (26), said arms pressing behind the hopper on a support that can participate in compaction (28) such as a smoothing plate and / or a cylinder.

According to the invention, the articulation on the transverse pivot axis (24) can be left free or blocked. It is left free, so that the vertical differences recorded by the vehicle are not reflected on the base of the machine relative to the support on the ground, for the implementation of ultra-thin layers with almost constant thickness, or it is locked and the freewheels (26) simultaneously excamoté in order to apply a layer coating with reprofiling effect.

In an appropriate embodiment, a machine for processing road materials, characterized in that the hopper (16) is towed by said vehicle, by means of two arms (20) articulated, each on said vehicle on an axis (21), said lateral arms (22) themselves being articulated on the arms (20) at the level of said transverse pivot axis 24.

Other characteristics and advantages of the subject of the present invention will appear on reading the detailed description given below in particular with reference to the appended figure which represents a schematic side view of the machine according to the invention, coupled with a feed tractor.

The entire left part of the figure with the general reference 10 represents a feeder tractor.

This is a particular traction means intended to ensure the advancement on the ground of the machine according to the invention.

This feeder tractor 10 fulfills the following main functions. By its front part, it pushes the semi-trailer trucks during the spreading, it receives and transfers the materials spilled by these trucks in the receiving and storage capacity 12. The transfer to the implementation tool, at a height suitable, being carried out by a transfer member, for example a conveyor with bars 14.

Finally, the feed tractor must have an adequate feed speed range.

In the use of ultra-thin layer spreading, the spreading machine according to the present invention is towed by the self-propelled feeder vehicle 10 without the vertical differences recorded by this vehicle being reflected on the base of the tool relative to the support.

The machine according to the present invention firstly comprises a densification and distribution hopper 16.

Given the required height of the hopper 16, the bar conveyor 14 must be arranged in an inclined manner, so that its upper discharge end is located at the right of the upper opening of the densification and distribution hopper 16 .

Thus, there is a large storage capacity of the material to be applied.

First of all, the hopper 16 advantageously having a width of the order of 3 meters may, in practice, have capacities close to approximately 4 tonnes of coated materials.

This hopper 16 is also coupled to the feeder tractor 10 which receives the materials and has for this purpose a first receiving and storage capacity 12 to which is added the reserve constituted by the stream of materials accumulated on the conveyor 14.

According to the present invention, the densification and distribution hopper 16 has a lower orifice 18 disposed close to the ground.

In practice, this opening 18 is located a few centimeters from the ground, and this so as to avoid any segregation of the road material towards the front.

A flap 19 can also be placed along the lower transverse edge before the hopper 16.

This hopper 16 is towed by means of two articulated arms 20, each on an axis 21 preferably placed in the middle of the wheelbase of the traction vehicle.

The hopper 16 can of course be fixedly mounted on its chassis with a wheelbase which will be adapted to the particular mode of implementation chosen. Thus, a short wheelbase, that is to say as close as possible to the front and rear sides of the hopper, will make it possible to follow the profile along the support as closely as possible.

In the particular embodiment described, the hopper 16 is mounted on lateral arms 22 themselves articulated on the arms 20 at a transverse pivot axis 24 which is arranged in front of the hopper 16 and which is supported by two idler wheels 26. The lateral arms 22 are also supported, behind the hopper 16, on a precompaction device. The latter may consist of a smoothing plate and / or a cylinder. One and / or the other of the two precompaction devices can advantageously be animated by a vibratory movement.

In the embodiment shown, this precompaction device is a cylinder 28.

Of course, the hopper is liftably mounted, mainly for transfer, by means of two jacks 30 placed on either side of the latter.

The densification and distribution hopper of the road material has a shape which has been determined to ensure good permanent flow of said material.

In practice, such a hopper 16 may have a cross section, in the direction of advance of the machine, narrowing downwards. To this end, one and / or the other of the front and rear transverse walls of this hopper 16 can be inclined.

In practice, the determination of the particular shape of the hopper, which may possibly depend on the particular nature of the road material spread, in fact results from a compromise between the need to ensure a permanent flow of the material, and the obligation maintain a sufficient filling height to allow the material accumulated in the hopper 16 to perform a densification function under the effect of its own weight, at the base of the hopper.

It is clear that the densification function is of particular interest in the application of layers of a certain thickness, but it also has a decisive advantage in the case of the application of ultra-thin layers since, in such a case situation, under the effect of the weight of the material accumulated in the hopper 16, a ground pressure is obtained which favors the fixing of the aggregates in the bonding layer.

In order to ensure the deposition of such a bonding layer, the assembly as shown in the appended figure may also be equipped with a transverse boom for spraying bituminous binders, bearing the reference 32.

Of course, the sprayer boom 32 is arranged in front of the hopper 16, it can be supplied by a supply truck depending on the machine.

Various experiments were carried out in order to determine what the average filling height of the hopper should be, in permanent operating conditions, to ensure a good densification, distribution and bonding function of the aggregate on the binder layer.

It has been found that a minimum filling height of between 0.5 and 1.2 meters, in particular a height of around 0.8 m, gives entirely satisfactory results.

It will further be specified that, in the case of a hopper having a transverse dimension of 3 meters, the opening 18 had a transverse dimension close to 80 centimeters.

During these experiments, spreading tests of ultra-thin and traditional bituminous concretes carried out under these conditions proved entirely satisfactory.

It is however possible to improve the conditions of implementation, to have recourse to a thermally insulated hopper 16.

As shown schematically in the accompanying drawing, the particular mounting of the hopper 16 on the chassis allows the application of the material in ultra-thin layers.

To this end, the hopper is mounted on arms 22 articulated on a pivot axis 24, which is arranged in front of said hopper and is supported by the idler wheels 26. In this case, spreading is carried out at constant thickness.

The articulation of the transverse pivot axis 24 is capable of being locked, and the idler wheels 26 can be simultaneously retracted, this so as to transform this method of mounting the hopper into another type of mounting allowing a coating of layers generally applied in greater thickness.

A transverse screw 34 ensuring the distribution of the material accumulated in the hopper is advantageously mounted in the upper part of the latter.

In practice, it is possible to use a screw having inverted threads tending to bring the cone of central accumulation of material towards the side walls of the hopper 16.

Still at the top of the hopper 16, it may also be advantageous to arrange feelers for detecting the minimum level of the material, these feelers being designed to control the feed device of the hopper.

It will be understood that a height of material is thus obtained under the distribution screw 34 which is large enough to ensure a useful volume of material, moreover ensuring a storage function necessary for the implementation of continuous work, which avoids the harmful consequences of machine stoppages due to the alternation of supply trucks.

It is clear that this phenomenon of accumulation in the hopper 16 also makes it possible to fulfill the densification function of the materials under the effect of their own load.

The hopper 16 is also equipped with a shutter 36 which makes it possible to close the lower part of the hopper 16.

In the closed position, the shutter 36 cuts the vein of material contained in the hopper in contact with the support and consequently isolates the content of the hopper from the support, which makes it possible to obtain stops and recoveries with straight and straight edges. transverse.

For restarting the machine, the shutter 36 is retracted by a hydraulic control cylinder, which again makes it possible to release the material present in the hopper.

The second essential element of the patented combination consists of the vibrating bar bearing the general reference 38, which is mounted in the immediate vicinity of the rear transverse edge 40 of the hopper.

Without rear supports on a horizontal plate as is the case for existing machines type finisher.

The vibrating bar 38 is animated by a vibratory movement, either mono- or polydirectional. The unidirectional vibratory movements will generally be vertical.

The frequency of the vibrations of the bar 38 is adjustable between values between 5 and 50 Hz.

In practice, a vibration frequency of the order of 25 Hz has led to entirely satisfactory results.

The amplitude of the vibrations of the bar 38 can also be adjustable, for example in ranges of values between 1 and 8 millimeters. In the case of a vibrating bar in the vertical direction with a frequency of the order of 25 Hz, an amplitude of variation of the order of 4 millimeters has led to completely satisfactory results in the case of concrete. traditional bituminous.

Finally, it is clear that the vibrating bar 38 itself is mounted on a support which can be adjusted in the vertical position.

Finally, it should be added that, advantageously, the rear edge 40 of the hopper 16 is equipped with a deflector not shown in detail, advantageously disposed in contact with the vibrating bar 38. This bringing this deflector into contact with the bar 38 can be achieved in practice using an elastic return means.

From a functional point of view, it will be specified that the vibration of the bar 38 participates in the crimping of the aggregates together on the bonding layer, particularly in the case of the production of very thin layers, that is to say when the the thickness of the layer is close to the largest particle size of the material used.

Finally, it will be noted that the vibrating bar 38 is designed with a profile which makes it possible to facilitate the cutting or shearing of the material as well as its positioning on the bonding layer.

A doming adjustment device in the center of this vibrating bar 38 ensures the spreading of roof materials, positive or negative.

This vibrating bar is advantageously produced in a hydraulically or mechanically extendable manner at the level of these two free ends, which allows the realization of variable working widths.

Such telescopic extensions of the vibrating bar 38 also make it possible to promote the production of the joints, the monitoring of the edges and the like because they can be controlled according to particular situations manually or automatically.

To supply this additional part with coating material, it is possible to provide on the lateral faces of the hopper 16, in their lower part, kinds of catteries closed by retractable shutters.

When the catteries are open, additional material is delivered to temporarily provide greater working widths.

Another way to vary the working width is to make a telescopic hopper.

Claims (14)

Machine for processing road materials, in particular for spreading road surface layers intended to be applied in layers of different thicknesses, in particular of bituminous concrete in ultra-thin layers, of the type comprising a chassis fitted with rolling means and able to be coupled to a traction vehicle (10) intended to ensure its advancement on the ground, characterized in that it comprises a hopper (16) for densification and distribution of said material, the lower orifice (18) of which is disposed close to the ground, as well as a vibrating bar (38) mounted in the immediate vicinity of the rear transverse edge (40) of said hopper (16). Machine for processing road materials according to claim 1, characterized in that the hopper (16) is mounted on arms (22) freely articulated on a transverse pivot axis (24) arranged in front of said hopper and supported by idler wheels (26), said arms resting behind the hopper on a precompaction device (28), such as a smoothing plate and / or a cylinder, so that the vertical differences recorded by this vehicle are not not reflected on the plate of the machine with respect to the ground, with a view to spreading coating in an ultra thin layer; the articulation on the transverse pivot axis (24) being able to be locked and the idler wheels (26) simultaneously retracted in order to apply a layer coating with reprofiling effect. Machine for processing road materials according to claim 2, characterized in that the hopper (16) is towed by said vehicle, by means of two articulated arms (20), each on said vehicle on an axis (21) , said lateral arms (22) themselves being articulated on the arms 20 at the level of said transverse pivot axis 24. Machine for processing road materials according to one of claims 1 to 3, characterized in that the hopper (16) has a predetermined shape to ensure good permanent flow of said material. Machine for processing road materials according to claims 1 to 4, characterized in that the hopper (16) has a large filling height making it possible to permanently receive a sufficient quantity of material to ensure its densification under the action of its own weight. Machine for processing road materials according to claims 1 to 5, characterized in that the average filling height of the hopper, in operating mode, is between 0.5 and 1.2 meters. Machine for processing road materials according to one of claims 1 to 6, characterized in that a transverse screw (34) for distributing the material is mounted in the upper part of the hopper (16). Machine for processing road materials according to one of claims 1 to 7, characterized in that at the upper part of the hopper are arranged feelers for detecting the minimum level of the material, capable of driving a device for hopper feed. Machine for processing road materials according to claim 8, characterized in that the hopper comprises a movable shutter (36) of the lower orifice (18). Machine for processing road materials according to one of claims 1 to 9, characterized in that the vibrating bar (38) is driven by a mono- or polydirectional vibratory movement. Machine for processing road materials according to claim 10, characterized in that the vibration frequency of the vibrating bar (38) is adjustable from 5 to 50 Hz. Machine for processing road materials according to claims 10 and 11, characterized in that the vibration amplitude of the vibrating bar (38) is adjustable between 1 and 8 millimeters. Machine for processing road materials according to one of claims 1 to 12, characterized in that the vibrating bar (38) is mounted on a support adjustable in height. Machine for processing road materials according to one of claims 1 to 13, characterized in that between the rear edge of the hopper (16) and the vibrating bar (38) is interposed a deflector advantageously applied against the bar vibrating using an elastic return means.

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