ITTO20120803A1 - SELF PROPELLED MACHINE FOR CONSTRUCTION SITE, IN PARTICULAR FOR SPECIAL FOUNDATIONS, AND METHOD FOR CHECKING ITS SUPPLY. - Google Patents

Description

TITLE: â € œSelf-propelled construction machinery, in particular for special foundations, and method for controlling its supplyâ €

DESCRIPTION

Technical field

The present invention relates to a self-propelled construction machine, in particular for special foundations, and to a method for controlling its supply.

More specifically, the present invention applies to tracked self-propelled construction site machinery (for example, cranes, drilling rigs, machines for driving consolidation or mixing, hydrofoilers, buckets, etc.), which are equipped with a combustion engine generally powered with diesel fuel (diesel cycle).

The aforesaid operating machines are intended to carry out, in particular, construction activities of special foundations in cyclical but prolonged work services, therefore considered as continuous.

Technological background

The aforesaid types of self-propelled construction machinery known to the state of the art have various drawbacks.

A drawback is given by the fact that, due to the continuous use of the machine in jobs that are increasingly complex and expensive in terms of power required for their execution, it is necessary to use ever greater quantities of diesel. Consequently, a first problem that follows and, in the unsolved state of the art, concerns the huge operating cost for use.

Furthermore, these machines are increasingly found to have to work in residential areas, near inhabited buildings where the problem of the pollution produced is very pressing.

To overcome these drawbacks, from the patent publication JP 2003-025858A it is known the possibility of installing compressed natural gas cylinders on the roof of a tractor with a mechanical shovel (hereinafter abbreviated with the acronym CNG) to power an engine. combustion. With respect to the application field to which the present invention addresses, the problems described below have not been solved.

The fixed installation of the tank on the roof of the cabin prevents the operator's view as prescribed by the typically applicable regulations, since, when in the presence of machines equipped with arms that develop in height or with guide towers for drilling tools, it is necessary to be able to leave a wide view over the cab roof, through which the operator keeps the situation under control. In addition, there is an additional danger due to the potential fall of objects from above, against which the car roof must withstand in accordance with the typically applicable regulations.

Furthermore, the aforementioned patent publication does not solve the problem related to the practical limitation present in the construction of a tank with capacity adequate to the autonomy required by the operating machines to which the present invention refers, that is to say several tons of weight that would not be applicable. on the cabins as they are not suitable for carrying such weights.

Finally, one of the most critical aspects is given by the fact that the engine is powered only by CNG supplied only by the cylinders present on the roof. This solution involves inoperative dwell times for the filling of the cylinders. Obviously, the time required for refueling is correlated to the volume of cylinders present which, in this case being limited (given the type of machinery illustrated which provides for applications with motor powers of a few tens of kW), implies a very low non-operating time.

The possibility of installing a compressed gas cylinder on the rear ballast is known from patent publication JP 11-062712 A.

However, these configurations concern the use of tanks characterized by limited capacities (that is, with motors of low applied power), which do not solve the problem of guaranteeing the autonomy required by the applications to which the present invention refers. Even if the tank capacity was increased considerably, a further unsolved problem is the need for long waiting times during refueling, which would force the operating machine to long non-operational stops.

Furthermore, the operating machines illustrated in the cited patent publications are equipped with rubber wheels and, therefore, can easily reach the refueling station to fill with combustible gas. On the contrary, the operating machines to which the present invention refers, being equipped with tracks, are characterized by additional limitations for the execution of refueling.

To solve the problems described, it is necessary to quickly replace the exhausted tank. Therefore these configurations do not solve the problem due to the difficulty of filling the exhausted cylinder, when it is not possible to have a refueling station inside the yard. Finally, as already illustrated for the previous publication, this type of set-up also envisages the use of only CNG as fuel for the combustion engine, with all the consequent implications.

Figure 6 of the aforementioned Japanese patent publication illustrates an additional tank, mounted on a trolley 62, to refuel the main cylinder installed on the lift. In this way the trolley 62 can be positioned near the machine to be refueled, but for the duration of this refueling, the machine cannot be used. Furthermore, the publication explains that, as for the method illustrated in figure 4 of this Japanese document, the refueling of the single cylinder can last for three hours, therefore a very long period of inactivity although the applied power is small and the need for the tank required is configurable in a single small cylinder.

Finally, the patent publication JP 2001-040705 describes the possibility of obtaining or integrating the compressed gas tank inside the rear ballast of an earth-moving machine. This configuration is not applicable to the case of operating machines for special foundations that require a large tank due to the high motor power required. In this case, unless the size of the ballast is increased excessively with the tank integrated, it is not possible to adequately balance the volume intended for the compressed gas, and subtracted from the ballast, in order to restore the overall weight of the counterweight necessary to guarantee the stability of the machine. As already indicated for the other publications, this document describes the fueling of the combustion engine with only CNG gas, consequently it only illustrates how the tank built inside the ballast can be refilled by opening the valve element ( indicated with 44 in the aforementioned patent publication) which is to be connected directly to a gas supply source. Therefore the rear ballast element remains fixed to the turret during refueling maneuvers and consequently the machine is not operational in these phases. Obviously this application is compatible only if the powers and therefore the consumptions are very limited (that is, request for small tanks).

Summary of the invention

One purpose of the present invention is to produce a self-propelled construction site machine capable of greatly reducing the amount of diesel fuel used for powering a high-power diesel cycle engine and consequently reducing the pollution produced and the operating cost of the machine.

According to the present invention, these and other purposes are achieved by means of a self-propelled construction site machine for special foundations, having the characteristics mentioned in the attached claim 1.

It is to be understood that the appended claims form an integral part of the technical teachings provided herein in the detailed description which follows regarding the present invention. In particular, some preferred embodiments of the present invention which have optional technical characteristics are defined in the attached dependent claims.

One of the advantages, achieved by some of the aforementioned optional technical characteristics, is that of creating a fuel gas tank that is equipped with a high capacity, in such a way as to cover the autonomy required by continuous high-volume work operations. power expenditure.

Another advantage, achieved by some of the aforementioned optional technical features, is that of allowing easy installation and removal of the fuel gas tank, equipped with a high capacity, from the load bearing superstructure of the machine, using handling systems. typically present on a construction site (for example, forklifts, service cranes, etc.) and without having to resort to special equipment. This advantage, in addition to that of being able to operate with a dual fuel (diesel or natural gas diesel oil), allows the machinery to remain operational even in the periods in which the gas tank is disassembled. In fact, in these moments the power supply is guaranteed by diesel only and stability is guaranteed by the presence of counterweights or ballast which remain applied to the rear part of the turret.

A further advantage, achieved by some of the aforementioned optional technical features, is that of making it easy to adapt existing machines (retrofit) and allow maximum flexibility in the choice of the gaseous fuel used.

Another advantage, obtained by means of some of the aforementioned optional technical features, is that of increasing the autonomy of the machine compared to known machines, in particular thanks to the installation of an additional tank for gaseous fuel having a high capacity. . Alternatively, the diesel tank could be reduced in capacity to save space inside the turret to house additional necessary components.

Another advantage, obtained by means of some of the aforementioned optional technical characteristics, is that of guaranteeing continuity of service with small interruptions in the operation of the machine, in particular thanks to the rapidity of replacement of the same and the programmed availability of storage tanks.

A further advantage, achieved by some of the aforementioned optional technical features, is that of making it possible to refuel at a remote station, transporting only the removable tank. In particular, this operation is performed without having to move the operating machine, which would not be acceptable, especially if the replacement were to take place when a work procedure (such as drilling, consolidation, driving, etc.) was not yet completed. .

Brief description of the drawings

Further characteristics and advantages of the present invention will become clear from the detailed description that follows, given purely by way of non-limiting example, with reference to the attached drawings, in which: - Figure 1 is a perspective view of a self-propelled construction machine in accordance with an exemplary embodiment of the present invention;

Figure 2 is an enlarged perspective view of some exemplary details of the machine shown in Figure 1;

- figure 3 is a perspective view of a tank which can be associated with the machine shown in the previous figures; - figure 4 is a schematic diagram representing a fluidic circuit which can be associated with the machine shown in the previous figures;

Figures 5 and 6 are perspective views of variants of embodiments of connection systems between the tank shown in the previous figures and the superstructure of the machine shown in the previous figures;

Figures 7 to 11 are perspective views representing a machine according to further embodiments of the present invention; And

- figure 12 shows some examples of handling means suitable for moving a tank which can be associated with a self-propelled construction machine according to the present invention.

Detailed description of the invention

With reference in particular to Figures 1 and 2, 100 indicates as a whole a self-propelled operating machine for construction sites for special foundations, in accordance with an exemplary embodiment of the present invention.

Machine 100 includes:

- a self-propelled substructure 102 equipped with tracks 102.1;

- a bearing superstructure 104 mounted on the self-propelled substructure 102 in a preferably rotating manner about a substantially vertical axis, particularly comprising a structural support frame 104.2;

- an equipment for the execution of special foundations 106 supported by the bearing superstructure 104 through an arm bearing element 107, preferably of the lattice or box type, with possible positioning kinematics, and arranged to perform at least one construction activity for special foundations;

- an internal combustion engine 108, in particular a high-power engine, fueled by diesel fuel and used for the generation of mechanical energy;

- an actuation system 110 arranged to convert and / or transmit the aforesaid mechanical energy in a controlled manner in such a way as to actuate at least one of the tracked self-propelled structure 102, the bearing superstructure 104, and the equipment 106.

The drive system 110 can be of the hydraulic type and include actuation systems, also typically hydraulic, used to perform the operating functions for which the machine 100 is responsible and to generate the movement of the machine itself. In some special versions, some main parts can be equipped with electric source motors or actuation elements, consequently the drive system is at least partly of the electric / electronic type. The internal combustion engine 108 is of the diesel cycle type, suitable to be powered with at least two types of fuel including:

- diesel e

- a mixture of diesel fuel and a gaseous fuel.

In the illustrated embodiment, the machine 100 includes a tank 109 (see Figure 4) adapted to contain diesel fuel inside and fluidly connected with the internal combustion engine 108, in such a way as to supply the latter with the € ™ supply of diesel fuel necessary for its operation.

Preferably the gaseous fuel comprises one of liquid natural gas (LNG), liquefied petroleum gas (LPG), or compressed natural gas (CNG).

In the illustrated embodiment, a cabin 104.1 is mounted on the supporting superstructure or turret 104, adapted to house an operator with the relative control devices.

The equipment for the execution of special foundations 106 can include different types of mechanisms and equipment suitable for carrying out operational activities in the construction sector for special foundations, such as drills, propellers, buckets, mixing tools, injector tools, buckets , cutters, pipes and driving elements in general, designed to perform operational activities in the construction sector and, in particular, deep foundations such as: poles, panels and diaphragms obtained by mixing.

In this embodiment, the actuation system 110 is preferably of the hydraulic type and comprises actuation systems, also hydraulic, used to perform the operating functions for which the machine 100 is responsible and possibly to generate the movement of the machine 100 itself.

In this embodiment, the internal combustion engine 108 is mounted on the bearing superstructure 104 and is therefore used to produce the energy necessary to power the drive system 110 and any actuation systems .

In particular, in at least one mode of use of the machine 100, a predetermined quantity of natural gas is mixed with air in the intake duct of the engine 108, before being introduced into the combustion chambers of the cylinders of the internal combustion engine 108. A calibratedly reduced part of diesel fuel is also injected into these cylinders in order to obtain a homogeneous, proportionate mixture of natural gas and diesel. The diesel introduced is mainly used to generate the ignition and combustion of the entire mixture when it is subjected to the compression generated by the internal combustion engine 108.

In the embodiments illustrated, natural gas is injected into the air intake duct of the internal combustion engine 108 through a suitable supply line. In particular, as will be described in more detail below with reference by way of example to figure 4, the supply line is equipped with suitable accessories and components, for example filters, pressure regulators, shut-off valves, and sensors. Furthermore, the internal combustion engine 108 is able to operate not only in dual fuel mode, but also in the traditional way, using diesel only when the natural gas line should be separated, for example when the gas fuel was exhausted.

With reference in particular to the embodiment illustrated in Figure 3, the gaseous fuel is suitable for being stored in a tank 112. In particular, the tank 112 has a high capacity in terms of volume and, as will be described in more detail in the following, it can be dismantled, making it easy to install / replace on board the machine 100. The fact that the tank 112 can conveniently be of high capacity is a consequence of several factors: first of all the high installed motor power, which is necessary for these types of work in the field of drilling for the execution of special foundations, then from the minimum autonomy that must be guaranteed to the machinery.

In terms of high applied power, we mean applications where several hundred kW are required. Powers in the order of tens of kW concern machines other than the machine 100 object of the present invention, which are very compact and can move easily, which do not make deep excavations and for which the working times are much less stringent. On the other hand, some types of drilling or mixing require many hours to complete and during some critical phases it is not possible to interrupt the work, especially if this interruption is very prolonged. Therefore it is necessary to minimize the number of interruptions (increasing the capacity of the tank) and the downtime of the machine (operating with a second type of fuel when the first is not available).

As can be seen in the embodiment illustrated by way of example in Figures 1 and 2, the tank 112 is installed at the rear on the superstructure 104 of the machine 100, i.e. in a remote and preferably opposite position with respect to the equipment 106 (and the relative arm 107) . In this embodiment it can be seen how the tank 112 is located in a distant and preferably opposite position with respect to the cabin With reference to the embodiment illustrated in Figures 1 and 2, the tank 112 is mounted on a base plate 182 projecting backwards with respect to the superstructure 104 (in particular, in a remote and advantageously opposite position with respect to the equipment 106) and usable for supporting a ballast 184 suitable for providing a counterweight for the machine 100 during its operation. By way of example, the tank 112 is shown arranged in proximity to the aforementioned ballast 184. Alternatively, the lower attachments can also be integral with the frame 104.2 of the supporting superstructure or turret 104.

As it is clear to a person skilled in the art on the basis of what will be described below, the tank 112 can be made in accordance with a plurality of implementation variants which are intended as examples and not limitations of the scope of the present invention which It is defined by the attached claims. In particular, these implementation variants refer to some advantageous aspects, including:

- the way in which the tank 112 can be connected to the superstructure 104,

- the use of hydraulic systems that automate operations,

- the structure of the tank 112, e

- the physical conditions (for example, pressure, temperature, liquid or gaseous state) in which the gaseous fuel is stored.

In this first embodiment the tank 112 is adapted to contain compressed natural gas (CNG).

Preferably the tank 112 comprises a plurality of containers 114, connected to each other, suitable for containing the compressed gaseous fuel. In this embodiment the tank 112 comprises a frame 116 suitable for housing and supporting the containers 114. Preferably the frame 116 is compact in shape, made in particular with a tubular structure, for example made of metal material, possibly of light alloy. Alternatively or in addition to the use of metallic material, synthetic material, for example plastic, or composite material can also be used. In this way, a frame structure 116 is therefore made that is light and particularly suitable for its handling, in such a way as to allow it to be easily replaced on the machine and transported to the refueling station.

By way of example only, it is estimated that the average volumetric consumption of gaseous fuel (in this particular case, compressed natural gas, particularly with a medium-high dosage ratio) in a machine 100 during a work shift is included, depending on the types in use, in an interval between 1m <3> and 5m <3> of CNG, therefore the dimensions of a tank intended for the storage of compressed gaseous fuel are absolutely relevant in relation to the dimensions exhibited by the machine.

In this embodiment, the containers 114 are cylinders having a substantially cylindrical shape and present in a size and number adequate to guarantee the required duration of supply of gaseous fuel. Furthermore, the containers or cylinders 114 are suitably arranged on board the machine 100, in particular on the bearing superstructure 104, in such a way as to maximize the use of the available space. For simplicity, in the accompanying drawings said containers or cylinders 114 are shown stacked according to a configuration having a substantially parallelepiped shape. However, as a function of the reduced dimensions of each container or cylinder 114 with respect to the overall dimensions of the tank 112, this configuration could clearly vary and take on different and even more complex shapes.

Advantageously, the containers or cylinders 114 can be chosen from those commercially available, already approved both for the high storage pressures of the CNG and for the use for which they are intended, in order to reduce the costs and risks associated with their implementation and use. with the internal combustion engine 108 of the machine 100.

Preferably, the containers 114 can be connected fluidly to each other in series, or divided into a plurality of groups of containers connected fluidly to each other in series, and these groups being connected in turn to each other in parallel. These containers, or groups of containers, are in turn connected in series with a gaseous fuel supply or delivery line intended to feed the internal combustion engine 108.

Preferably, the containers 114 are placed side by side and stacked, for example according to a horizontal arrangement (see for example Figures 1, 2, 7 and 8) or according to a vertical arrangement (see Figures 9 and 8). 10), particularly arranged according to an orientation in which their prevalent extension is substantially horizontal or vertical. In particular, by modifying the frame 116 or by assembling and / or reciprocally placing several frames side by side (see figure 7) it is possible to increase the number of containers that can be stored and consequently increase the autonomy of the machine 100.

With reference in particular to the embodiment illustrated in Figure 12, the movement of the tank 112 to install and remove it on / from the machine 100, and in particular from the superstructure 104, is carried out using handling systems normally present in a construction site. In the example shown, the tank 112 is able to be handled by using forklift trucks F and service cranes C. In particular, the trolley F and the crane C are able to pick up the frame 116 and then moving the plurality of built-in receptacles 114 from the reservoir 112.

With reference in particular to Figure 10 and as will be described in more detail below, the loading and unloading of the tank 112 from the machine 100 can alternatively be carried out by means of at least one hydraulic actuator device 118, for example with power supply, mounted in the rear area of the machine. 100, in particular of the superstructure 104. The hydraulic actuator device is capable of allowing the tank 112 to be loaded and unloaded from the rest of the machine 100, for example from the superstructure 104.

With particular reference to the embodiment illustrated in Figures 2 and 3, the tank 112 can be mechanically coupled with the rest of the machine 100, in particular with the superstructure 104, by means of a quick coupling connection system.

Preferably the connection system includes at least one cylindrical joint. In this embodiment, the mechanical coupling between the tank 112 and the superstructure 104 occurs by means of a pair of upper cylindrical joints 120 and a pair of lower cylindrical joints 122. Particularly the cylindrical joints 120 and 122 are located between one side of the tank 112, in particular of the frame 116, and the superstructure 104.

Preferably at least one of the cylindrical joints 120 (122) comprises:

- a fork 120.1 (122.1) associated with one of the tank 112 and the superstructure 104, in particular the frame 104.2, and

- an attachment plate 120.2 (122.2) in turn associated with the other between the tank 112 and the superstructure 104 and removably pivotable in the fork 120.1 (122.1).

In this embodiment the fork 120.1 (122.1) is associated with the superstructure 104, while the attachment plate 120.2 (122.2) is associated with the tank 112, in particular in correspondence with a side of the frame 116. However in variants of embodiment not shown this configuration can also be reversed.

In particular, the cylindrical articulation 120 (122) includes a pin 120.3 (122.3) able to cross transversely the respective fork 120.1 (122.1) and the attachment plate 120.2, (122.2) inserting itself in a respective seat 120.4 (122.4).

In the embodiment illustrated with reference to Figures 1 to 3, the seats 122.4 of the pair of lower attachment plates 122.2 have an open cross section, in particular at the bottom, while the seats 120.4 of the upper attachment plates 122.4 have a closed cross section . In this way, the geometry of the lower attachment plates 122.2 makes it possible to initially rest the tank 112 on the lower pins 122.3 (preliminarily inserted through the corresponding openings of the lower forks 122.1) during the assembly phase, and to stably constrain the tank 112 to the superstructure 104 when the upper pins 120.3 are simultaneously inserted through the forks 120.1 and the attachment plate 120.2. Pins 120.3 and 122.3 can be inserted manually or by means of suitable hydraulically actuated devices. This system can also be realized in the reverse way, with the open cross section placed at the top and the pins are inserted at the bottom.

In this embodiment, the assembly of the device on board the superstructure 104 of the machine can take place by means of the forklift F as illustrated in Figure 12.

According to a further variant of the present invention, the cylindrical joints 120, 122 are equipped with an insertion system provided with snap devices capable of rapidly and automatically locking and unlocking the same pins 120.3 and 122.3 to facilitate the replacement maneuvers of the containers. or gaseous fuel containers 114.

In this regard, to ensure adequate safety, a suitable device is able to enable the locking and unlocking of the tank fixing systems 112, allowing the completion of the disassembly and assembly phases. This security could consist of a key or combination lock that frees access to the release means, a particular software or electrical / electronic enabling if the release devices are remotely controlled, and for example of the hydraulic or pneumatic type. or electric.

Preferably, a control device can analyze some functions and enable unlocking only when at least one or more minimum conditions are met; for example: when the shut-off valves on the supply line are all closed, when the gaseous fuel level has dropped below a minimum value, when there are no employees nearby, when the connections to the engine are disconnected .

With reference in particular to Figure 4, an example of the fluidic connection of the tank 112 with the internal combustion engine 108 will be described below.

The containers 114 suitable for containing compressed natural gas (CNG) are connected to each other by means of a three-way valve 124. A further three-way valve 126 connects the pipeline leaving the containers 114 with a charge coupling 128, since a non-return valve 130 which prevents unwanted leakage of natural gas. On the tank outlet line there are a manometer 132 for measuring the pressure and a safety solenoid valve 134.

Solenoid valve 134 is electrically powered by an ignition key through a special remote control switch. With the solenoid valve 134 de-energized (engine off or running only with diesel fuel) the natural gas output from the tank towards a pressure reducer unit 144 is prevented. With the solenoid valve 134 energized (engine running and operating in dual fuel mode: fuel gas oil) the way to the pressure reducer unit 144 is opened, putting the tank 112 in communication with the engine fueling system. In order to increase the safety of the system and avoid overpressure or fast emptying of the tank, the safety solenoid valve 134 can be equipped with suitable safety devices (for example, fuse pad, flow limiter, mechanical overpressure device) .

The tank 112 is connected to the supply line of the operating machine by means of a quick coupling 138 and a flexible pipe 140. The tank 112 and the supply line of the operating machine can be isolated (for example, during maintenance or replacement operations tank) thanks to two shut-off valves 142, present at the inlet of the natural gas supply line and at the outlet of the tank 112.

The pressure of the natural gas leaving the tank 112 is reduced by a suitable pressure reducer 144, with one or more stages, equipped with a heating circuit that uses the liquid from the engine cooling circuit, avoiding the pressure drop during the the freezing of natural gas. A possible variant of the heating circuit of the pressure reducer involves the use of a circuit, independent from the engine cooling circuit, on which a dedicated exchanger is installed. This solution has the advantage of keeping the two heat exchange circuits (engine cooling and methane pressure reducer heating) independent and not altering the existing engine system.

An additional pressure regulator 146 is controlled by the control unit (not shown) of the dual fuel system for the desired metering of natural gas.

The natural gas is mixed with the air in the intake duct via the mixing valve 148. Subsequently, the mixture of air and natural gas is introduced into the combustion chamber of the diesel engine 108, or preferably before the turbocharger 160 when present. .

Further, the circuit further comprises a filter 150, a minimum pressure sensor 152, a pair of further pressure gauges 154, a maximum pressure sensor 156, an air filter 158, a turbocharger 160, and a coolant pump 162.

Finally, the diesel fuel supply line, indicated as a whole with 164, comprises at least one tank, a filter and a pump for circulating the diesel fuel for inlet to the combustion chamber.

The replacement operation of the exhausted removable tank 112 is carried out by closing both interception valves 142 and, subsequently, disconnecting the quick coupling 138. After that, using the same means used for loading on board the tank 112 and repeating in reverse of the installation operations, the tank 112 is removed from the operating machine and is loaded onto a vehicle for transport to the filling station where the tank 112 will be filled by means of the charge coupling 128.

The operations for replacing the tank 112 mounted on the machine 100 can be advantageously carried out in a short time, thus reducing machine downtime, and having another full tank ready to be installed on site.

Furthermore, the refueling station could be located at a great distance from the work area of the machine and not necessarily present inside the construction site, as the autonomy guaranteed by the tanks allows for a planned supply over time and with reasonably long times.

In a non-preferred form, the loading of the gaseous fuel into the containers 114 could take place without the disassembly of the same (and therefore of the overall tank 112) from the superstructure 104. When the gaseous fuel level falls below the minimum value, the The combustion engine power supply is switched to diesel only and by closing the valves 142 or acting on the solenoid valve 134, it is possible to fluidically isolate the containers from the line that connects them to the engine. Therefore, with the machine running, it is possible to fill the tank 112 by bringing the charging coupling or charging point 128 to an externally accessible area, without mechanically releasing the tank 112 from the superstructure 104. This procedure involves reaching the operating machine with an external refueling system.

The control system of the machine 100, having estimated the average consumption and the dosage percentages, sends information on the expected duration of the cylinders 114 and this information is managed by the employees (operator, site controller) to program gas purchases, supplies of procurement and internal movements in the construction site areas, in compliance with safety regulations. To implement these functions previously described, the tank 112 is equipped with suitable sensors. In particular, the level of gas present in the containers 114 can be monitored in two ways, depending on the emptying sequence used.

If the emptying of the pressure vessels 114 occurs at the same time, that is to say that the individual vessels 114 are connected to each other and to the single supply / dispensing line without internal shut-off valves, the supply / dispensing line is equipped with one or more pressure sensors which, by measuring the value of the pressure inside the tank 112, generate a warning signal when the pressure drops below a minimum preset value.

If the emptying of the pressure vessels is sequential, that is to say that the tank is composed of containers 114 or groups of containers 114 which empty one after the other and separated by suitable shut-off valves, a automatic system monitors the pressure in each container 114 or group of containers 114 and, once the minimum pressure level has been reached, it can switch, even automatically, the supply from the empty container to a full one and send a signal to the control system, which displays on the display in the cabin or sends this residual autonomy data to those who have to manage the supply logistics on site.

Alternatively, by exploiting the fact that in particular in the embodiment illustrated with reference to Figures 1 to 3, the structure of the tank 112 is hung from upper pins 120.3, at least one of these can be instrumented to determine the weight of the tank 112 When this weight reaches the minimum value, the control panel transmits a message to refuel the gaseous fuel.

The control system can therefore detect data (such as pressure and weight) indicative of the residual volume of fuel.

With reference to the embodiment illustrated in Figure 5, the lower attachment plates 122.2 are provided with lower seats 122.4 adapted to receive the lower pins 122.3 and having a closed cross section. In this case the tank can be moved with a forklift truck F so as to position the upper attachment plates 122.2 crossed by a single rod 123.1 with the relative pin in correspondence with curved hooks 123.2 carried by the superstructure 104, after which at least one lower fixing system, preferably of the pin type as a locking system. Also in this case the insertion of the pins 122.3 in the seats 122.4 and through the forks 122.1 can be done manually or by means of suitable hydraulically actuated devices. Also in this embodiment, the rod 123.1 can be permanently attached to the upper attachment plates 122.2.

With reference in particular to the embodiment shown in Figure 6, a further variant of the quick coupling connection system is shown. In this variant, the pair of upper cylindrical joints 120 is substantially similar to that shown in Figure 2 or to that shown in Figure 5, and therefore need not be described again hereinafter. On the other hand, the tank 112 is provided at the bottom with a pair of support plates 166, in particular protruding from the frame 116, adapted to rest against respective support plates 168 carried below by the superstructure 104. In this way it is maintained, in the In use, a substantially upright attitude of the tank 112 against the superstructure 104.

Preferably in this embodiment the locking of the tank 112 is assisted by a mechanical or hydraulic tie rod 170 mechanically interposed between the tank 112 and the superstructure 114. In particular, the tie rod 170 is inserted between the base of the frame 116 and a lower portion of a part of the superstructure 104. In this way, the tie rod 170 mutually locks the tank 112 and the superstructure 104, keeping them in mutual support between the plates 166, 168 and preventing reciprocal oscillation around the upper cylindrical joints 120.

With reference in particular to Figures 7 and 8, a further embodiment of the present invention is illustrated. In this embodiment the connection system as previously described is absent and the tank 112 is installed, in particular resting and fixed, on a support or shelf 172 projecting from the superstructure 104, preferably at the rear.

The support or shelf 172 can be connected in a removable way to the superstructure 104, for example by one of the methods described above with reference to the installation of the tank 112. In particular, for the removable fixing of the support or shelf 172, a combination of:

- one or more pairs of cylindrical joints having seats with open and / or closed cross section, e

- one or more tie rods, mechanical or hydraulic, suitable for locking the bracket 172 to the superstructure 104.

Also in this case, the insertion of pins can be done manually or by means of suitable hydraulically actuated devices.

With reference in particular to Figure 8, alternatively the support or bracket 172 is permanently fixed to the superstructure 104 of the machine 100, for example through a welded structure or a bolted structure which requires a long assembly time and therefore the tanks 112 they can be dismantled according to one of the methods described above.

With reference in particular to Figure 11, a further embodiment of the present invention is illustrated, in which the support or bracket 172 is movable, in particular in a guided way, with respect to the superstructure 104 of the operating machine 100. For example, the support o shelf 172 is able to move, with respect to the superstructure 104, according to one of the following methods mentioned below:

- a vertical translation;

- a rotation about a horizontal axis oriented in a direction transverse to the superstructure 104 of the machine 100;

- a suitable combination of the aforesaid translation and of the aforesaid rotation; And

- a movement of the articulated quadrilateral type.

In particular, Figure 11 shows a mechanism 174 of the articulated quadrilateral type, for example comprising a pair of oscillating arms 176 and a respective pair of pins 178 of the quick-coupling type, the insertion of which between the arms 176 and the frame 116 It is obtained manually or automatically, advantageously through suitable hydraulic devices.

The displacement in accordance with the variants indicated above allows the tank 112 supported by the shelf 172 to be raised and lowered to facilitate its loading and unloading from the superstructure 104. Preferably, the movement of the support or shelf 172 is performed by means of suitable hydraulic actuation 180.

Such embodiments of the present invention, previously described, can be installed on traditional machines 100 in which the disassembly of a ballast is not required, if it is present. This has an advantage when it is necessary to disassemble the tank for refueling or necessary maintenance, being able to guarantee that the stability of the general machine is unchanged and therefore operate in the non-specified modes.

According to a less preferred variant of the present invention, the tank 112 can be installed in at least partial replacement of the ballast 184 associated with the machine 100. In this case the tank 112 is installed and fixed on the same base plate 182 or directly on the frame 104.2 which It is normally used to support the aforementioned ballast 184 and is loaded on the superstructure 104 of the operating machine 100 by means of the same hydraulic devices originally used to load the ballast 184. In this case, during the disassembly phases of the tank 112, the machine will be able to continue to operate but in a de-calibrated manner taking into account the real loss of counterweight. The advantage, however, is the reduction of the overall weight of the machine 100 in operating conditions.

As is clear to a person skilled in the art, even if in all the embodiments illustrated in the drawings the tank 112 is shown equipped with a plurality of pressure vessels 114 connected to each other in an adequate number, the tank can also include a single container or cylinder, or possibly the gaseous fuel, can also be stored in different physical conditions, for example in order to reduce the overall volume of the tank.

In this regard, as previously mentioned, the tank 112 can also be adapted to contain an alternative fuel to compressed natural gas and suitable for mixing with diesel. For example, it is possible to use Liquid Natural Gas (LNG) or Liquefied Petroleum Gas (LPG) contained in a tank consisting of a single container by virtue of the low pressure required for storage which allows to significantly increase the diameters of the cylinder. of the CNG. Clearly, also in this case the installation modalities of the tank 112 on board the superstructure 104 of the machine are maintained as previously described, while the power supply system is instead provided with the necessary accessories, depending on the specific fuel used and in accordance with the state of the art, for introducing fuel into the air intake duct.

According to the present invention it also relates to a method for controlling the supply of gaseous fuel in the machine 100 previously discussed. In particular, the method includes the following operating phases in order:

- mount the tank 112 on the superstructure 104; - detect indicative data of at least one of the following parameters:

the volume of gaseous fuel present in the tank 112,

the average consumption of gaseous fuel by the internal combustion engine 108 during the operation of the machine 100,

the generally constant speed of the internal combustion engine 108,

the percentage of utilization of the power of the internal combustion engine 108,

the percentage of metering of the gaseous fuel used;

- estimate a duration or a value of expected residual autonomy of the gaseous fuel contained in the tank 112 according to the aforementioned indicative data according to pre-established criteria; And

- transmit a signal indicative of this duration or value of residual autonomy.

Preferably, the method further comprises, as a function of the aforementioned indicative signal, the operating step of supplying and delivering another tank 112 full of gaseous fuel in proximity to the machine 100.

Preferably, the method also includes, in order, the following operating phases:

- closing at least one of a first shut-off valve 142 located at the outlet of the tank 112 and a second shut-off valve 142 located in the inlet of a supply line of the internal combustion engine 108;

- disconnect a quick coupling 138 connected between the inlet of the power supply line and the outlet of the tank 112; And

- remove the tank 112 from the superstructure 104.

Preferably, the method also includes, in order, the following operating steps:

- loading the tank 112 removed from said superstructure 104 onto a means of transport;

- transport the tank 112 to a refueling station; And

- fill tank 112 with gaseous fuel under pressure.

Preferably, the method provides for the fact that the machine 100 allows the disassembly of the tank 112 from the superstructure 104 according to an enabling process upon the occurrence of at least one minimum required condition among the following:

- the shut-off valves on the supply line are all closed,

- the gaseous fuel level has fallen below a minimum value,

- there are no employees nearby,

- the motor connection connections are disconnected.

Preferably, the method envisages the fact that the aforementioned minimum required condition is given by the use of at least one of the following systems:

- a key lock,

- a combination which deactivates release means (for example the devices for controlling the insertion and the disconnection of the pins 120.3 and 122.3) adapted to hold the tank 112 mechanically connected to the superstructure 104, and

- a particular software or electrical / electronic qualification.

Preferably, the method provides that the activation of the starting procedure of the machine 100 is allowed when the assembly of the tank 112 on the superstructure 104 is completed, i.e. when the tank 112 is fixed on the superstructure 104 and all the connections mechanical and fluidic have been restored.

Preferably, the method provides for the fact that, when the level of gaseous fuel contained in the tank 112 falls below the minimum value, the power supply of the combustion engine 108 is switched to diesel only, interrupting the flow of gaseous fuel coming from the tank 102 towards the combustion engine 108, in particular by means of at least one of the following operations:

- close a first shut-off valve 142 located at the outlet of the tank 112 and a second shut-off valve 142 located in the inlet of a supply line of the internal combustion engine 108, and

- close a safety solenoid valve 134 located at the outlet of the tank 112;

the tank 112 being filled without deactivating the internal combustion engine 108, for example by moving to an externally accessible area a charge coupling 128 carried by the tank 112 and able to allow the filling of the tank 112, without mechanically releasing the tank 112 from the superstructure 104 .

Naturally, the principle of the invention remaining the same, the embodiments and construction details may be widely varied with respect to what has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention. as defined in the attached claims.

In particular, the technical characteristics which differentiate the different variants and embodiments described and illustrated from each other are freely interchangeable with each other, where compatible.

Claims (18)

CLAIMS 1. Self-propelled operating machine (100) for construction sites, in particular for special foundations, comprising: - a self-propelled substructure (102) equipped with tracks (102.1); - a bearing superstructure (104) mounted on said self-propelled substructure (102) preferably rotating around a substantially vertical axis; - an equipment for the execution of special foundations (106) supported by said superstructure (104) through an arm bearing element (107), preferably of the lattice or box-like type, and arranged to perform at least one construction activity for special foundations; - an internal combustion engine (108) fueled by diesel for the generation of mechanical energy; - an actuation system (110) arranged to convert and / or transmit said mechanical energy in a controlled way to actuate at least one of said self-propelled structure (102), said supporting superstructure (104), and said equipment (106); at least one tank (112) arranged to contain a gaseous fuel and comprising at least one container (114) in the shape of a cylinder; said tank (112) being rear mounted on the superstructure (104) in a detachable way; said engine (108) being fed with at least two types of fuel including diesel and a mixture of diesel and gaseous fuel, in which in at least one operating mode of said machine (100), a predetermined quantity of gaseous fuel is mixed with air in an intake duct of said engine (18), before being introduced into a combustion chamber of said engine (108). 2. Machine according to claim 1, wherein said gaseous fuel is one of liquid natural gas (LNG), liquefied petroleum gas (LPG) and compressed natural gas (CNG). 3. Machine according to claim 2, wherein said tank (112) is constituted by a plurality of containers (114) connected fluidically to each other, said gaseous fuel being compressed natural gas (CNG). 4. Machine according to any one of the preceding claims, wherein said tank (112) can be quickly disassembled from the superstructure (104) through a quick coupling connection system (120, 122); said machine further comprising valve means (142, 134) arranged to prevent fluid communication between said engine (108) and said tank (112), allowing the supply of diesel oil only to said engine (108) when said tank (112 ) is removed from said superstructure while maintaining the operation of the machine (100). Machine according to any one of the preceding claims, in which said tank (112) can be loaded / unloaded onto / from said supporting superstructure using at least one hydraulic actuator device (180). 6. Machine according to claim 4, wherein said connection system comprises at least one cylindrical joint (120, 122) which comprises a fork (120.1, 122.1) associated with one of said tank (112) and said superstructure (104), and an attachment plate (120.2, 122.2) associated with the other between said superstructure (104) and said tank (112) and removably pivoted to said fork (120.1, 122.1). 7. Machine according to claim 6, wherein said attachment plate (120.2, 122.2) has a seat (120.4, 122.4) adapted to transversely house a pin (120.3, 122.3) which passes through said fork (120.1, 122.1) and said plate attack (120.2, 122.2); the cross section of said seat (122.4) being open or closed. 8. Machine according to claim 6 or 7, wherein the tank (112) is mounted on a support or shelf (172) projecting from said superstructure (104) and can be removably installed on said bearing superstructure (104). 9. Machine according to claim 8, wherein said support or bracket (172) is movable, by means of at least one hydraulic actuator, in a guided way with respect to said bearing superstructure (104). 10. Machine according to any one of the preceding claims, wherein said superstructure (104) comprises a base plate normally intended for connection with a ballast and which is at least partially used to fix said tank (112), where said tank (112) It can be moved on said base plate by means of hydraulic devices normally designed to move said ballast. Method for controlling the supply of gaseous fuel in a machine (100) made according to any one of the preceding claims, comprising, in order, the following operating steps: - close at least one of a first shut-off valve (142) located at the outlet of said tank (112) and a second shut-off valve (142) located in the inlet of a supply line of said internal combustion engine (108) ; - disconnecting a quick coupling (138) connected between said inlet of the supply line and said outlet of said tank (112); And - removing said tank (112) from said superstructure (104). Method for controlling the supply of gaseous fuel in a machine (100) made according to any one of claims 1 to 10, comprising in order the following operating steps: - mount the tank (112) on the superstructure (104); - detect indicative data of at least one of the following parameters: the volume of gaseous fuel present in said tank, the average consumption of gaseous fuel by said internal combustion engine (108) during the operation of said machine (100), the generally constant speed of said internal combustion engine (108), the percentage of power utilization of said internal combustion engine (108), the percentage of dosage of said gaseous fuel used; - estimating a duration or an expected residual autonomy value of the gaseous fuel contained in said tank (112) as a function of said indicative data according to predetermined criteria; And - transmit a signal indicative of this duration or value of residual autonomy. Method according to claim 12, further comprising the operative step of supplying and delivering another tank (112) full of gaseous fuel in proximity to the machine (100) according to the aforesaid indicative signal. 14. Method according to claim 11, further comprising, in order, the following operating steps: - loading said tank (112) removed from said superstructure (104) onto a means of transport; - transporting said tank (112) to a refueling station; And - refueling said tank (112) with gaseous fuel under pressure. Method according to any one of claims 11 to 14, wherein said machine (100) allows the disassembly of said tank (112) from said superstructure (104) according to an enabling process upon the occurrence of at least one minimum condition required between the following: - the shut-off valves on the supply line are all closed, - the gaseous fuel level has fallen below a minimum value, - there are no employees nearby, - the motor connection connections are disconnected. 16. Method according to claim 15, in which said minimum required condition is given by the use of at least one of the following systems: - a key lock, - a combination which deactivates release means adapted to retain said tank (112) mechanically linked to said superstructure (104), - a particular software or electrical / electronic qualification. Method according to any one of claims 11 to 16, wherein the activation of the starting procedure of said machine (100) is allowed when the mounting of the tank (112) on said superstructure (104) is completed. 18. Method according to any one of claims 11 to 17, wherein when the level of gaseous fuel contained in said tank (112) falls below the minimum value, the fuel supply of the combustion engine (108) is switched to diesel only, interrupting the flow of gaseous fuel coming from said tank (102) towards said combustion engine (108), in particular by at least one of the following operations: - close at least one of a first interception valve (142) located at the ™ outlet of said tank (112) and a second shut-off valve (142) located at the inlet of a supply line of said internal combustion engine (108), and - closing a safety solenoid valve (134) located at the outlet of said tank (112); said tank (112) being filled without deactivating said internal combustion engine (108), for example by moving to an externally accessible area a charge coupling (128) carried by said tank (112) and able to allow the filling of said tank ( 112), without mechanically releasing said tank (112) from said superstructure (104).