Description Cold recycling machine, for recycling the road pavement and for road repaying

Technical Field

The present invention relates to a self-propelled machine used in road repaying by cold recycling of the bituminous conglomerate that forms the pavement.

Background Art

Machines and related processes for the recycling of bituminous conglomerate are known since a long time. These machines can be generally subdivided in two main groups, that is, those which perform a cold recycling and those which perform a hot recycling. The hot recycling technology is employed in particular for the recycling of the upper layers of the pavement, and generally for reduced depths up to about 5 cm. In substance, during hot recycling two or more pre-heaters are employed for preheating the pavement, and these cooperate with the machine used to mill the pavement which is in any case preheated up to about 12O ⁰ C; the machine then mixes the milled conglomerate with aggregate and bitumen, within a mixer, and spreads the resulting material by means of a common, road finishing machine.

A variant of this technology is the cold milling of the bituminous conglomerate, for layers which in this case are deeper than the 5 cm of the above case, and the mixing of the aggregate within a mixing furnace having features similar to those of a fixed plant, where the term "fixed plant " (in the present patent application) generally means an equipment suited to recycle the milled conglomerate transported to the plant by means of lorries or the like, and a plant that uses lorries or the like in order to transport the recycled material to the work area (where the recycled material is spread by the finishing machine). The cold recycling technology also involves the base layers and the so-called

"binder" of the pavement, the latter being in this case cold-milled up to a theoretical depth limit equal to 20 cm.

The cold recycling technology is the technology which is most directly related to the present invention. In cold recycling, the machines involved are the following:

- a scarifier or road pavement milling machine, employed for great depths;

- a sieve;

- a mixer;

- a finishing machine. Obviously, also required are tanks for the emulsion, water, additives, etc., to be added inside the mixer to the milled, bituminous conglomerate to be recycled. To better clarify in the following description the advantageous features of the present invention, we will briefly recall the nowadays commercially available cold-recycling machines. ♦ One of the major manufacturers of recycling machines for recycling bituminous conglomerate is the company Wirtgen GmbH, having its seat in Windhagen (Germany). The cold recycling machines commercialised by it are a development of its own technologies of hot recycling that have been put on a sound basis since a long time. These machines (that actually form a "machine train" if one includes the storing tanks for the virgin, additional materials) comprise all technical parts (scarifier (milling machine), mixer, finishing machine) in a single, self-propelled vehicle that may reach considerable dimensions - i.e. a size of 12.20m x 3.00m x 3.00m and a weight of about 75000 kg -, and for this reason, a special trolley needs to be used for its transportation. Therefore, the machine is conceived or designed prevalently for a deployment on long distances (long stretches).

In operation, the machine cold-mills (scarifies) the pavement and automatically loads the material obtained by the milling operation into the mixer. Amounts of bituminous emulsion, water, and possibly cement, are added within the mixer. These additions

are made using microprocessor-controlled pumps, which inject and add the water needed to provide compactness, the water required for bitumen foam generation, and finally the bitumen. These pumps are mounted on ducts. The ducts are connected through flexible ducts to the water tanks and the bitumen tanks, the latter actually forming separate lorries travelling in front of the recycling machine. Therefore, a real "train" of enormous size is formed, which also requires a noticeable work for its management due to its limited manoeuvrability.

The company Marini S. p. A. is another manufacturer of in situ recycling machines. The operations are in this case as follows: - milling or scarification of the pavement and creation of a grit line (linear heap, or heap line) with the milled (scarified) material;

- loading, performed by the cold-recycling and mixing machine;

- discharge of the product into a finishing machine, performed by a loading means/vehicle; - spreading and compaction of the bituminous conglomerate.

Generally, the same operational features also apply to other existing machines, that is:

♦ a reduced manoeuvrability;

♦ a considerable length of the "machine train"; ♦ difficulties in transportation.

As last example of cold-recycling machine one can mention a machine manufactured by the French company Appia, which is one of the major French road manufacturers, and which includes in its machine stock a model of cold-recycling machine named EMF 200. It seems that until now this machine has been employed in France only on by-roads. As a further disadvantage of this kind of cold recycling machine, since the finishing machine (spreader) is incorporated (integrated) in its rear part, if the recycled material that is spread and compacted presents undesirable features at a certain

moment during the work, that may for instance be due to a failure or malfunction of the water and bitumen injection pumps, and if the operators become aware of this fact, they are obliged to lift the bench (frame) of the finishing machine (by actuating the respective hydraulic jacks), and to move the finishing machine forwards; then, they need to remove the layer of undesirable (defective) material that has however already been spread and compacted, and thereafter, they must move the machine rearwards, reposition the bench of the finishing machine at the operative height, and restart the machine in the direction of advancement. AU these operations/steps are obviously fatiguing and laboursome, and they reduce the work efficiency. Moreover, since the mixer of this prior art machine is located centrally and in the machine interior, one must wait that the recycled material having said undesired features has been completely discharged (unloaded) from the mixer, before restarting the machine. A further disadvantage of this conventional machine is that it has its emulsion spraying nozzles located in a central region which is difficult to reach (where said mixer is also provided); therefore, if one of the spraying nozzles becomes clogged during the work, this gives rise to many problems and possibly the work itself must be stopped. One of the main distinguishing features of the machine manufactured by Appia is that it does not provide any addition of cement into the mixer, since this is not provided for by the French technical specifications.

An object of the present invention is to provide a working machine adequate for commercial needs, with respect to:

♦ flexibility; ♦ easy handling or management;

♦ less costs related to manpower;

♦ easiness of manoeuvring ; because of its very limited dimensions (1 Im x 2.90m x 3.40m), and which also

allows to realise the processing simultaneously in two different road yards, or which can operate as a fixed plant, as will be clarified in the following. The inventors of the present invention have noticed that a lower productivity (per hour) with respect to already existing, commercialised machines, does not mean great disadvantages from the point of view of the efficiency, for a company that has to perform road maintenance works, because the time lost by the machine of the present invention in a specific road yard due to the lower 'work rate' (work speed) of the machine, with respect to machines of greater size, is amply repaid by the fact that during displacements from one road yard to another, there is no need of a convoy or escort, the dimensions are by far lower, and therefore the manouevrability is far better, and there is no need of disassembling parts of the machine in order to permit its transportation.

This machine, which is easy to manoeuvre (also on by-roads or state streets), is capable of performing and completing, within two days, a road repaving work of small entity, in two different road yards, which is impossible to obtain with a machine of very big size. Moreover, it does not require a time interval of days in order to perform the displacement of the means/vehicles and for the deployment of the same means/vehicles in a subsequent road yard, not to mention the time - if any - required by the use of a convoy, and also the concrete possibility of performing the required works (many machines cannot work on state roads or side roads, because_of their excessive dimensions). Thus, the main features of the machine according to the present invention are:

• during the recycling process it can cope with, and solve, any problem/need that may arise, even an unexpected one; • it is easy to load on, and to unload from, a normal semitrailer;

• the maintenance is easy and rapid due to the particular care and attention paid in the assembling of the various components;

• it can move autonomously, also to carry out small repair works ("patches") inside a

region characterised by a single group of road signs;

• it is adapted and suited to operate easily also outside motor-ways.

Disclosure of Invention The basic inventive concept of the present invention lies in that the conventional cold-recycling machines have been reduced to their essential parts, while remedying at the same time to their various drawbacks. It has been already shown that one of these drawbacks consists in their excessive dimensions, which limit or hinder the manoeuvrability in certain circumstances. Therefore, a sort of "separation" has been made, including (in the machine) only those equipments which are necessary for performing the cold-recycling of the bituminous conglomerate, in such a way that the machine of the invention only comprises the most important unit or "heart" needed to perform the cold-recycling, whereas all the other parts will only be auxiliary parts of reduced size or in any case are manoeuvrable with extreme ease, and moreover, they are also already present on the market.

Therefore, to the advantage of practicality and economy, the machine of the present invention only includes a loading chamber ("loading hopper"), and a mixer, and all required components used during the recycling process of the asphalt. In other words, on the machine there will be mounted water tanks, cement tanks, bituminous emulsion tanks, and tanks for possible additives, together with means suited to weigh the amounts of conglomerate that needs to be recycled (milled material loaded on the machine), and means suited to correspondingly meter the percentages of water, cement, bituminous emulsion, and possible additives. All the remaining equipment, that is, the milling (or scarification) machine (whose size and efficiency will be selected in accordance with the kind of work to be done), does not form part of the machine of the present invention, and the same holds for the finishing machine and the possible loader used to charge the material (which has already been recycled by the machine of the present invention) in the loading chamber of the finishing

machine. A noticeable advantage of this kind of organization of the equipments lies in the fact that it will also be possible to use the (above mentioned) auxiliary equipments made available in the yard for instance by firms which operate in this field, thereby noticeably reducing transportation costs. The machine according to the present invention will correspond to the heart or core of the process, and according to one of its possible embodiments it will occupy a space of about 11 metres in length, 3.00 m in width, and less than 4.30 m in height (including the trolley for loading the machine on the semitrailer). Therefore, this size of the machine will permit its immediate transport on any kind of semitrailer with specific permission, without the necessity to previously disassemble some parts of the machine. However, due to its width of 3.00 m (in this particular embodiment) and to its height of 3.40 m (without taking account of the trolley), it will in any case be necessary to ask for a permission for exceptional loads, to be allowed to travel on a motor- way without any convoy (escort). A further technical distinctive feature of the machine according to the present invention lies in the fact that it can be used as a fixed plant in the vicinity of a storehouse of milled bituminous conglomerate; for instance, the machine can work in a service area or in a lay-by of a motor- way located in proximity of the actual road yard. In this case the milled material is transported by means of lorries from the road yard to the machine of the present invention and then it is directly loaded on the machine of the present invention (which now operates as a "fixed plant"); thereafter, bituminous emulsion, cement, and other additives are introduced into the mixer of the machine, then, the machine performs recycling of the loaded material, and other transport means (lorries) are employed for transporting the recycled material to the finishing machine(s) which is (are) working in the road yard.

Therefore, any skilled person immediately understands the advantage of the machine of the present invention, which, without any structural modification, can be directly used both as a fixed plant and as a "mobile plant", thereby enhancing its versatility

and economy and adapting itself to the most different needs. According to claim 1, the machine includes a front part and a rear part, wherein the chamber or plane used to load the milled material is provided in the front part, while the rear part includes the mixer. Between these two parts - the front and rear parts -, there are weighing and transport means for the milled material, which serve to continuously transport and weigh the milled material previously loaded on the loading plane or in the loading chamber.

In case the machine is used exclusively as fixed plant, no crawler tracks for its displacement are necessary, or any other means allowing its movement, but only supports suited to support the weight of the machine and to resist to static and dynamic loads (weight of the loaded material; etc.); however, preferably the machine will be provided with such drive means, in particular crawler tracks, both on its front side and rear side, to increase stability in any circumstance and to be able to work indifferently as "mobile plant" or "fixed plant". Moreover, the machine is provided with tanks for the bituminous emulsion, water tanks, and preferably also with tanks for cement and other additives, which are directly mounted on the machine in contrast with the prior art according to which tank trucks are often used to transport the materials added (loaded) in the mixer (see above). The speed of the transport means used to transport the milled material to the mixer is preferably adjustable.

The addition of bituminous emulsion, water, and cement, and other possible additives, is metered depending on the weight of the material transported by said transport and weighing means. To this end suitable metering means are provided, which meter the respective amounts of bituminous emulsion, water, and cement. Therefore, since the metering is performed based on the weight, and not based on the volume of milled (scarified) material, the percentages of the various components contained in the recycled material will be far more precise and constant

in time. The metering function is managed automatically by a PLC (a processor or "programmable logic controller") based on the output signal of the weighing means (load cell); this signal, in mA (milliampere), will vary between mimmum and maximum values (4 -20 mA), the minimum value obviously corresponding to a state in which no milled material is being loaded on the machine.

The batching or metering means can be chosen in the most suitable way. Said metering means can be implemented by electric pumps supplied with electric power from the generating set, which is also mounted on the machine. However, if desired, hydraulic pumps can also be used. In the following detailed description of one machine embodiment, the water pumps and the emulsion pumps are embodied by electric pumps (pumps driven by electric motors).

The addition of cement in metered amounts is performed by means of a metering screw (auger) which is again driven by the electric energy supplied by the generating set. However, other metering means could be provided to feed the cement, and therefore the invention is not limited in this respect.

An internal combustion engine is provided (on the machine) to drive the crawler tracks (if they are present, that is, if the machine is self-propelled and serves as mobile plant) and in order to supply the necessary power to the hydraulic pumps coupled to the output shaft (driving shaft), these pumps serving for actuating all hydraulic motors and the various ancillary equipments of the machine (for instance the hydraulic jacks associated with the loading plane or loading chamber of the milled material, the motor that rotates the vanes of the mixer, and so on). The machine includes heating means for heating the bituminous emulsion with the aid of the thermal oil used to heat them, said thermal oil being circulated into ducts arranged inside gaps provided in the tank of the bituminous emulsion. For example, the thermal oil may be heated to a temperature of 200°C. An additional technical and constructive feature which renders even more convenient

the use of the machine according to the present invention used for cold-recycling the bituminous conglomerate of a road pavement, lies in the fact that all its metering means, and also the thermal oil ducts and emulsion ducts, are arranged in the rear part of the machine and are mounted perfectly in view, so that they remain accessible for any repair or replacement work possibly carried out by those working in the road yard. Therefore, in a preferred embodiment, all metering means, and all end parts of the ducts (extending from the respective tanks) used to feed the substances which are admixed inside the mixer, are in view in the upper part of the mixer, which preferably is open at its upper side. A further advantage, related to the construction technique of the mixer, lies in its cantilevered, articulated connection that facilitates the discharge operations for the recycled material from the mixer, should the road have a slope hindering an easy discharge. The complete process of repaving includes the following steps: ♦ cold milling of the pavement by means of a conventional road paving milling machine (not forming part of the present invention), and loading of the milled material on a lorry;

♦ discharge of this milled material from a lorry, into the hopper (loading chamber) of the recycling machine of the present invention, or recovering this milled material arranged in a heap line on the ground, using a loader (e.g.: a bucket elevator or elevating conveyor belt);

♦mixing, inside the mixer, by adding bituminous emulsion, water, and preferably cement;

♦ loading the recycled material into the finishing machine (conventional, not included in the present invention), or laying the recycled material on the ground and recovering the same by means of an inclined bucket elevator connected to the front part of the finishing machine (see above), if the present machine is used as "mobile plant"; or loading the recycled material on a lorry by means of a loading conveyor

belt placed at the output of the mixer, only if the machine is used in the modality "fixed plant", in which case the lorry will bring this material to the finishing machine (of conventional type);

♦ spreading and compaction, performed by the conventional finishing machine and by two rollers one of which is a rubber roller and the other is of a combined metal- rubber kind.

Usually, in the operation as "mobile plant" of the machine according to the present invention, the finishing machine automatically receives the recycled material - previously laid on the ground in the form of a heap line — from said loader (bucket elevator) hooked to the front of the finishing machine, or alternatively, the finishing machine is arranged directly below the outlet (opening) of the mixer. Evidently, the modalities of use of the machine according to the present invention may amply differ from each other in accordance with individual requirements; that is, the typology of the employed auxiliary means, not making part of the present invention (finishing machine, milling or scarification machine, etc.), and their use, may vary depending on circumstances.

The most important advantages that can be obtained have already been discussed in detail, and other ones will also be discovered when the invention is put into practice. The lower productivity per hour with regard to the obtained recycled material (less than 200 tons/hour), equal to about 150 tons/hour in a particular embodiment, will be amply repaid by the extreme versatility of the machine. Its relatively small dimensions (length no more than about 11m, width no more than 3.00 m, and height at most equal to 3.40m) allow for example to work on by-roads even without special permissions.

Brief Description of Drawings

The above advantages, together with other advantages and features of the present invention, will be described with reference to the annexed drawings and to a specific,

preferred embodiment of the invention, which is to be considered purely illustrative and in no way limitative or binding for the present patent application, wherein:

FIGURE 1 is a side view of one side of the machine according to the present invention, which has been sectioned along the broken line A-B-C in order to make visible the inner parts of the same;

FIGURE 2A is a side view of the machine according to the present invention, relating again to the same side of the machine as in Fig. 1;

FIGURE 2B is an enlarged view, with respect to Fig. 2 A, only of the rear side of the machine;

FIGURE 3 is a side view of the other side of the machine according to the present invention;

FIGURE 4 is a view of the rear side of the machine according to the present invention;

FIGURE 5 is a schematic, plan view of the cold-recycling machine according to the present invention;

FIGURE 6 is a schematic view showing the machine according to the present invention during its operation as mobile plant;

FIGURE 7 is a schematic view showing the operation of the cold-recycling machine as fixed plant, for instance in a lay-by or service area of a motor- way.

Disclosure of a Preferred Embodiment of the Invention

The present invention will now be described in detail, referring to the drawings and to a particular embodiment thereof, which is shown in these drawings, where the same components of the machine are always indicated by the same reference numbers in all figures 1 to 7.

The cold-recycling machine for recycling the bituminous conglomerate forming the road pavement, includes a loading hopper 21 located on the front side, into which the milled (scarified) material is loaded by a scarification or milling machine (the latter not being shown and not forming part of the invention). The loading hopper may be lifted, as well as tilted (by a system of jacks and levers), in order to facilitate loading of the milled (scarified) material.

As shown in Fig. 5, this loading hopper 21 is centrally provided with a loading belt conveyor 22 and with two lateral body sides that can be lifted by means of hydraulic jacks in order to gradually push the already loaded milled material towards the central region of the hopper 21, that is, to the region of the loading conveyor belt 22; the latter has an adjustable "throughput" (mass flow capacity), that can be adjusted by an operator by a speed regulation of the belt, and it is used to convey the milled material towards the rear side of the machine (towards the mixer 9). The milled material is handed over by the loading belt 22 to the transport and weighing means, which in this embodiment are implemented by a continuous weighing belt 18 with a width of 5900 mm, provided with a commercial-type weight integrator (Thermo Ramsey, model MINI 11-101 P/F), the latter being indicated only schematically by a rectangle 19 in Fig. 1. Thereafter, as may best be seen in Fig. 1, the milled (scarified) material that was "handed over" to the continuous weighing belt 18 by the loading belt 22, is discharged (falls by gravity) into the mixer 9 (located in the rear part of the machine), while water, bituminous emulsion, and preferably cement and/or other additives are also added thereto.

In the present embodiment, the machine also has crawler tracks 23 (four in number, that is, two fore ones and two rear ones), which are driven by a respective hydraulic motor associated each with a respective crawler track, so that the machine may both be used as a mobile plant (self-propelled vehicle) and as a fixed plant, according to circumstances, without being forced to make any modifications to the machine. In this manner the machine will always be ready for the intended use. The water to be added to the mixer 9 is stored inside at least one tank, and in the present embodiment there are two water tanks which are obviously interconnected (see Fig. 2A). These tanks are indicated by the numbers 12 (rear tank) and 14 (fore tank). The rear tank 12 has the following features: size 400 x 1700 x 1300 mm. The fore tank 14 has the following technical features: L-shaped section and a volume of 1437.5 1. It is used to load the water.

The machine also includes a tank 2 for the bituminous emulsion, which is mounted on the upper, central part, and which in this specific embodiment has the following dimensions: 1900 x 2900 x 1150 mm and a capacity of about 5000 1. The bituminous emulsion is discharged from the tank 2 and charged in the mixer 9 through the duct 33 (Fig. 2B), after opening the respective manually operable tap (valve) shown in Fig. 2B in proximity of the tank 2 and on the duct 33 itself. As follows from this figure, the duct 33 communicates and forms a "right angle" with another duct, 32, (which carries a further tap or manually operable valve), which at its free end forms a pipe fitting for a hose (flexible duct) (not shown). In practice, in the modality of operation corresponding to a "mobile plant", the valve of the duct 32 is closed and the valve of the duct 33 is opened so as to unload (discharge) the emulsion from the tank 2 into the mixer 9, by letting it pass only through the duct 33. Instead, in the operation modality corresponding to a "fixed plant", there is no need in using necessarily the emulsion tank 2, and a hose of a tank truck containing the same bituminous emulsion can be directly connected to the free end of the duct 32, after having previously closed the manually operable valve of duct 33 and (obviously)

after opening the valve of duct 32. Therefore, if the valve of duct 33 is opened, the valve of duct 32 must remain closed, and vice versa.

Moreover, in Fig. 2B it may be noted that the duct 32 presents a branching duct of reduced diameter which first extends up to a nozzle-carrying block 10 located on the same machine side, and then continues up to a second nozzle-carrying block (also indicated by reference number 10) located symmetrically on the other side of the machine (cf. figures 4 and 5). Said blocks 10, equipped with their respective nozzles, are used to spray a so-called "asphalt levelling course or primer" of bituminous emulsion, as well-known to those skilled in the art; moreover, since the nozzles may function intermittently, it is in any case required that a return duct be provided for re- circulating the bituminous emulsion to the emulsion tank 2. Obviously, the nozzle- carrying blocks 10 will serve to spray the emulsion only when the machine is operating in the modality "mobile plant", and for this reason a manually operable valve is provided also on said branching duct of reduced diameter associated with the duct 32 (cf. Fig. 2B).

Clearly, it is preferred that the bituminous emulsion be directly heated through means already provided (that is, already incorporated) in the machine. To that end, the machine is provided with a heater of the thermal oil, indicated by reference number 20. The energy required to heat the thermal oil is supplied to the burner of the heater by a generating set (power unit) 11 located in the lower part of the machine (cf. for instance Fig. 2A).

Reference number 24 denotes the expansion tank of the thermal oil. The thermal oil is circulated within a closed circuit, through a plurality of ducts, and branching ducts of lower diameter. A first function of said ducts and branching ducts or pipes is - as mentioned above - that of supplying the thermal oil used for heating, to the bituminous emulsion tank 2 in order to heat the bituminous emulsion. A second function consists in supplying said thermal oil to the (electric) pumps used for dragging the bituminous emulsion. In fact, during the starting step of the

machine, said pumps must be "heated up" in order to liquefy the deposits of bituminous emulsion which otherwise, in the long run, would clog the apertures (passages) of the pumps.

These pumps, in the present non binding embodiment, are electric pumps, and their respective drive motor is supplied with electric power from the generating set 11 (technical features of the generating set: size 1830x730x990mm, manufactured by Gen Set, model MG 22 SS-L).

A first electric pump for dragging the emulsion is indicated by the reference number 4. It forms a loading pump for loading the emulsion in the mixer 9. This gear pump has the following technical specifications. Model FA7, warmed up, with bare shaft, and a delivery (capacity) of 7000 1/h at a speed of 1450 rpm. The absorbed power during dragging of the emulsion corresponds to 3 kW.

Near said gear pump 4 it is possible to see (cf. Fig. 2B) the small-diameter ducts for the thermal oil, which in this case are connected in parallel. The second (electric) pump used to drag the emulsion is also shown in Fig. 2B and is indicated by the reference number 8. It consists of a gear pump and it is used as a circulating pump for dragging that portion of the emulsion necessary to realise the asphalt levelling course and fed to the nozzle-carrying blocks 10 arranged on both sides of the machine. This pump is also "heated" by the thermal oil. It is of a commercial kind and its technical features, that are obviously non-binding, are the following in the present embodiment of the invention: model FA3, heated up, bare shaft, delivery of 1000 1/h at the maximum speed of 5000 rpm. The power required for dragging the hot bituminous emulsion is 1.5 kW. There is also provided a loading pump 1 for loading the ("cold") emulsion into the bituminous emulsion tank 2, this loading pump 1 being located in the upper central region of the machine, near the bituminous emulsion tank 2 itself. A respective loading duct, for loading the bituminous emulsion in the "mobile plant" modality, is also shown in Fig. 2 A, and it passes through said (gear) pump (loading pump) 1,

having a delivery equal to 10 m ³ /h.

The gear pump utilised for the circulation of the thermal oil is indicated by reference numeral 13. This pump (cf. Fig. 1) is arranged in the vicinity of the transport and weighing means 18, 19, that is, near the continuous weighing belt 18 with the load cell (or weighing unit) 19. The technical specifications (features) of this gear pump 13 for the thermal oil, in the present, non-binding embodiment of the invention, are as follows: model FA2, with bare shaft, and delivery of 2000 1/h at a speed of 1450 rpm. The power required for dragging the thermal oil is 1.1 kW. The pump used to feed water from the tanks 14 and 12 into the mixer 9 is indicated in the figures (see in particular Figs. 2A and 2B) by reference number 5. In this non- binding embodiment, this pump is a centrifugal pump with a maximum delivery of 60 1/min.

The feed ducts for feeding water from the tanks 12 and 14 to the mixer 9, and the taps (valves) mounted on these ducts, are clearly visible in Fig. 2 A and in Fig. 2B. The cement is charged in powder form (not in slurry form) into the respective tank 3 for the cement, located in the upper part of the machine. The capacity of the tank 3, in the present, non-binding embodiment of the invention, is equal to about 1.74 m ³ . Near the tank 3, there are provided two filters 6, one for each of its sides (cf. Figs. 4 and 6). One of their functions is to prevent the formation of voids inside the tank, and therefore to optimise the capacity of the same. The filters 6 are cleaned now and then by means of compressed air provided by a compressor 15. This compressor 15 also allows to open/close the nozzles of the nozzle-carrying blocks 10, 10. The cement in powder form is discharged into the mixer 9 and the cement amount is metered by means of a metering auger or metering screw which is denoted by numeral 7 and is provided with an electric motor. The metering screw has a diameter of 138 mm and a dragging power of 1.5 kW. The electric motor of the metering screw is supplied with electric current by the generating set 11. The screw 7 can be easily dismounted from the tank 3 for a possible repair or replacement.

In the rear part of the cold-recycling machine of the present invention, used to recycle the bituminous conglomerate, there is provided the above mentioned mixer 9 which has the following technical characteristics: size 1206 x 2620 x 750 mm, model MC150, maximum production rate 150 m ³ /h. These specifications can obviously vary and are not binding.

The mixer 9 is cantilevered and can be rotated around a fulcrum with horizontal axis by acting on lifting means (levers, etc.) which - for instance - are visible in Fig. 1 and which rest on the ground by means of wheels. The possibility of rotating the mixer 9 allows to easily discharge on the ground the recycled bituminous conglomerate, when working on a sloping road and in the modality "mobile plant", thereby permitting to form the heap line 28 of recycled bituminous conglomerate (cf. Fig. 6 in which however there is no problem of sloping ground).

All the above components (water, emulsion, cement, but also possible additives) are discharged in metered amounts into the mixer 9 by the respective metering means (pumps, 5, 4, and metering screw 7) according to the output signal provided by the PLC that receives an input from the weighing means 19. Thus, the batching or metering of water, bituminous emulsion, and cement (virgin materials) is performed according to the weight of the milled (scarified) material of bituminous conglomerate which is discharged into the mixer 9 by the continuous weighing belt 18. Reference number 17 denotes a hydraulic motor (model P50) with epicyclic reduction gear 16, suited to drive the vanes of the mixer 9 (these vanes are not shown).

Finally, Figs. 6 and 7 show the operation of the machine according to the present invention. Fig. 6 shows the operation modality of the machine of the present invention as "mobile plant". A lorry 25 unloads the milled material (the milling or scarification machine is not shown) into the loading hopper 21 of the recycling machine of the present invention, the latter being generally indicated by reference number 26. The

recycled material, or "final product", is discharged on the ground and forms a so- called heap line 28. A bucket elevator, or elevating conveyor, 27, charges the recycled bituminous conglomerate into the finishing machine 29, and the latter performs the spreading and compacting of this material. Instead, Fig. 7 shows the operation modality as "fixed plant". In this case a conveyor belt 30 loads the recycled material of bituminous conglomerate on a lorry 31 and the latter transports it - for instance - from a lay-by/service area where the machine 26 according to the invention is located, to the nearby road yard, and finally discharges it into the finishing machine. In conclusion, the above explained technical and constructive features and those of the working process, which substantially distinguish the present invention from other ones, result in substantial advantages like:

- compactness and easiness of transportation from one road yard to another; no necessity to ask for a convoy (escort); - manoeuvrability also in by-roads;

- easy maintenance, because, as results from Fig. 2A, all the pumps are mounted in view, or in any case are directly accessible simply by dismounting a protective covering (housing), and for this reason the pumps may be replaced or repaired in situ also by the operators charged with the road repaving works; - the machine can work both as "mobile plant" and as "fixed plant", without requiring modifications;

- the tanks are mounted on the machine and therefore there is no need of additional tank trucks that would give rise to a real "machine train" of excessive dimensions;

- preferably, a tank for cement is also provided, which aids in accelerating the solidification of the conglomerate, by the absorption of water.

The present invention has been illustrated only for illustrative and non-limitative purposes.

List of reference numbers and words

1 gear pump for loading the emulsion in the tank

2 emulsion tank

3 cement tank

5 4 gear pump for loading the emulsion into the mixer

5 centrifugal pump for water

6 filters

7 cement metering screw

8 gear pump for the emulsion levelling course ("primer") 10 9 mixer

10 nozzle-carrying block for spraying the emulsion

11 generating set (power unit)

12 water tank

13 gear pump for the thermal oil 15 14 water tank

15 compressor

16 epicyclic reducer

17 hydraulic motor of the mixer

18 continuous weighing belt 20 19 weighing unit (load cell)

20 heater of the thermal oil

21 loading hopper

22 loading conveyor belt (associated with the hopper 21)

23 crawler tracks

25 24 expansion tank for the circuit of the thermal oil

25 lorry

26 recycling machine according to the invention

27 loader

heap line finishing machine conveyor belt lorry