CROSS-REFERENCE TO RELATED APPLICATIONS This patent application claims priority from Italian patent application no. 102019000017540 filed on 30/09/2019, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD The present invention relates to a system for manufacturing metal objects by die-casting.

In particular, the present invention relates to a system for manufacturing metal objects by die-casting a liquid metal material in a foundry unit. BACKGROUND ART

As is generally known, systems for manufacturing metal objects by die-casting comprise a melting furnace, configured to supply a liquid metal material, a plurality of machines for the die-casting, a plurality of maintaining furnaces configured to maintain the liquid metal material within a predefined temperature and feed the liquid metal material to the machines for the die-casting and a conveying system for transporting the liquid metal material from the melting furnace to the maintaining furnaces and supplying the maintaining furnaces. Currently, the supply of the maintaining furnaces is conducted by an operator, who applies an empirical supply method, based solely on his or her own experience which could compromise the quality of the metal objects produced, the rationalization of the time and resources dedicated to the die-casting processes and the prevention of breakdowns caused by the non-feeding of liquid metal material which could potentially cause stoppages in the production of the metal objects. DISCLOSURE OF INVENTION

The object of the present invention is to provide a system for manufacturing metal objects by die-casting which mitigates the drawbacks of the prior art.

In accordance with the present invention, a system is provided for manufacturing metal objects by die-casting a liquid metal material; the system comprising:

- a melting furnace configured to supply liquid metal material;

- a plurality of machines for the die-casting of the liquid metal material;

- a plurality of maintaining furnaces, each of which is associated with at least one respective machine for the die casting, is configured to contain the liquid metal material, maintain the liquid metal material within a predefined temperature range, and feed the liquid metal material to the at least one respective machine for the die-casting, and comprises a measuring device configured to provide a level signal indicating the level of the liquid metal material inside the respective maintaining furnace;

- a conveying assembly of the liquid metal material, configured to feed the liquid metal material from the melting furnace to each maintaining furnace; and

- a control unit configured to determine a priority among the maintaining furnaces to be supplied with the liquid metal material according to the level signals provided by the measuring devices; the conveying assembly comprising a ladle having a capacity, and a cart, configured to transport the ladle to at least one of the said maintaining furnaces; the control unit being configured to emit a supply consent signal if the sum of the volumes comprised between the maximum level and the level of liquid metal material of each maintaining furnace measured by the respective measuring device equals or exceeds the capacity of the ladle.

By means of the present invention, it is possible to optimize the distribution of the liquid metal material so as to reduce to the minimum the paths of the liquid metal material, prevent machine stoppages and ensure a better quality of the metal objects produced.

Moreover, it is possible to improve the efficiency of the system and ensure better safety conditions for the system operators, by determining the optimal supply sequence of the maintaining furnaces and supplying the maintaining furnaces only when necessary.

By means of the ladle and the cart, it is possible to vary the supply sequence of the various maintaining furnaces so as to increase the flexibility of the supply operations.

In other words, it is possible to supply the maintaining furnaces without following a predefined supply sequence.

Moreover, the consent signal for the supply of metal material into the ladle is emitted only when the total amount of the metal material to be supplied to the maintaining furnaces to be supplied equals the capacity of the ladle.

In this manner, it is possible to limit the number of supply operations of the maintaining furnaces reducing the costs and risks associated with such operations.

In particular, the control unit is configured to emit a consent signal for the supply of the liquid metal material from the melting furnace according to the level signals provided by the measuring devices. In this manner, it is possible to establish the point in time when to initiate the supply operations of the maintaining furnaces so as to reduce to the minimum the number of supply operations.

In particular, the system comprises at least one signaling device, which can be activated in response to the consent signal; the signaling device comprising a graphical interface configured to display information related to the maintaining furnaces to be supplied and to the consent signal for the supply of the liquid metal material.

In this manner, it is possible to display on the graphical interface the information relating to the supply operations of the maintaining furnaces so that it is immediately understandable to an operator in charge of the supply operations.

In particular, the control unit comprises a memory containing a minimum level and a maximum level of the liquid metal material for each maintaining furnace; and wherein the control unit is configured to emit the consent signal for the supply of the liquid metal material when the level of the liquid metal material of at least one of the maintaining furnaces measured by the respective measuring device falls below the minimum level.

In this manner, it is possible to signal if the level of liquid metal material in one of the maintaining furnaces falls below the minimum level, so as to initiate the supply operations of said maintaining furnace in order to maintain in operation the at least one associated machine for the die-casting .

In other words, the supply of the maintaining furnace having the level of metal material below the minimum level is carried out with absolute priority. In particular, the memory contains an average rate of consumption of the liquid metal material of each machine for the die-casting; the control unit being configured to predict the level of liquid metal material of each maintaining furnace as a function of the average rate of consumption of the at least one associated machine for the die-casting and the level of liquid metal material measured by the respective measuring device.

In this manner, it is possible to estimate in advance the point in time when to initiate the supply of the liquid metal material from the melting furnace so that the total amount of the metal material to be supplied to the various maintaining furnaces to be supplied equals the capacity of the ladle.

In accordance with an alternative embodiment, the cart is self-driven. In this manner, the conveying of the ladle to the maintaining furnaces to be supplied is carried out automatically, thus reducing the costs of the supply operations .

In particular, each maintaining furnace comprises a lid with automatic opening; the control unit being configured to control the opening and the closing of each lid.

In this manner, it is possible to control the opening of the lids of only the maintaining furnaces to be supplied, so as to avoid the supply of a wrong maintaining furnace.

In particular, the measuring device comprises a laser sensor.

In this manner, it is possible to measure the level of liquid metal material inside each maintaining furnace keeping each measuring device at a distance from the liquid metal material, so as to avoid the overheating of the measuring devices.

A further object of the present invention is to provide a method for manufacturing metal objects which reduces at least one of the drawbacks of the prior art. According to the present invention, a method for manufacturing metal objects by die-casting a liquid metal material is provided; the method comprising:

- providing liquid metal material by means of a melting furnace; - providing a plurality of machines for the die-casting of the liquid metal material;

- providing a plurality of maintaining furnaces, each of which is associated with at least one respective machine for the die-casting and is configured to contain the liquid metal material, maintain the liquid metal material within a predefined temperature range, and feed the liquid metal material to the at least one respective machine for the die casting;

- measuring the level of the liquid metal material inside each maintaining furnace; - determining a priority among the maintaining furnaces to be supplied with the liquid metal material as a function of the measured levels;

- feeding the liquid metal material from the melting furnace to each maintaining furnace to be supplied via a ladle, which has a given capacity and is transported by a cart; and

- emitting a consent signal for the supply of the liquid metal material from the melting furnace if the sum of the volumes of each maintaining furnace comprised between the maximum level and the level of liquid metal material measured equals or exceeds the capacity of the ladle.

In this manner, it is possible to improve the efficiency of the supply operations, optimizing the available resources.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the present invention will become apparent from the following description of a non-limiting embodiment example, with reference to the attached figures, wherein:

- Figure 1 is a schematic view, with parts removed for the sake of clarity, of a system for manufacturing metal objects by die-casting in accordance with the present invention;

Figure 2 is a schematic view, with parts removed for the sake of clarity, of a detail of the system for manufacturing metal objects by die-casting of Figure 1; and

- Figure 3 is a schematic view, with parts removed for the sake of clarity, of the system for manufacturing metal objects by die-casting of Figure 1, in accordance with a second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to Figure 1, a system for manufacturing metal objects by die-casting is indicated as a whole with reference numeral 1.

In particular, the present invention relates to a system 1 for manufacturing metal objects by die-casting a liquid metal material in a foundry unit, without thereby limiting the wide range of potential applications of the present invention.

In accordance with the present invention, the system 1 comprises a plurality of machines 2 for the die-casting of liquid metal material; a plurality of maintaining furnaces 3, each of which is configured to contain the liquid metal material and comprises a measuring device 4 configured to provide a level signal indicating the level of the liquid metal material inside the respective maintaining furnace 3; a control unit 5 configured to receive the level signals provided by the measuring devices 4, process such level signals, and emit guidance signals for the supply operations of the maintaining furnaces 3.

In the particular example shown in Figure 1, six machines 2 for the die-casting are shown in a row as well as six maintaining furnaces 3, each of which is associated with a respective machine 2 for the die-casting. The number and the arrangement of the machines 2 for the die-casting and of the maintaining furnaces 3 are purely illustrative and are not to be understood as limiting of the scope of protection of the present invention. Moreover, in accordance with a variant of the present invention, not shown in the attached figures, at least one maintaining furnace 3 is associated with a plurality of machines 2 for the die-casting.

In accordance with a further variant of the present invention, not shown in the attached figures, at least one machine 2 for the die-casting is associated with a plurality of maintaining furnaces 3.

Each maintaining furnace 3 is configured to maintain the liquid metal material within a predefined temperature range, and feed the liquid metal material to the respective machine 2 for the die-casting.

In the preferred embodiment, non-limiting of the present invention, each measuring device 4 comprises a laser sensor configured to measure the level of the liquid metal material inside the respective maintaining furnace 3. More specifically, the laser sensor is configured to emit a laser beam that is reflected by the surface of the liquid metal material contained inside the maintaining furnace 3. This reflection of the laser beam is captured by the laser sensor, which, by triangulation, determines the distance between the laser sensor and the surface of the liquid metal material contained inside the maintaining furnace 3.

In accordance with alternative embodiments, the measuring device 4 comprises an ultrasonic level sensor or a radar level sensor.

The control unit 5 is configured to emit a consent signal for the feeding of the liquid metal material to the maintaining furnaces 3 and to determine a priority among the maintaining furnaces 3 to be supplied with the liquid metal material according to the level signals provided by the measuring devices 4.

Moreover, the system 1 comprises a melting furnace 6 configured to supply liquid metal material; a conveying assembly 7 of the liquid metal material, configured to feed the liquid metal material from the melting furnace 6 to each maintaining furnace 3 to be supplied.

The melting furnace 6 is configured to receive a solid metal material, melt the solid metal material, and supply the liquid metal material.

Although a single melting furnace 6 is shown in the particular example of Figure 1, in accordance with alternative embodiments, the system 1 can comprise a plurality of melting furnaces 6.

In the particular example shown in Figure 1, the conveying assembly 7 comprises a ladle 8 having a capacity, and a cart 9, configured to be guided by an operator so as to transport the ladle 8 to the maintaining furnaces 3. Moreover, the system 1 comprises two signaling devices

10 and 11, connected to the control unit 5 and configured to receive the guidance signals for the supply operations of the maintaining furnaces 3 emitted by the control unit 5, so as to be perceived and understood by the operator. In particular, the signaling device 10 is stationary and comprises a screen configured to display said guidance signals.

The signaling device 11 is mobile and is configured to be transported by the cart 9 and to be viewed by the operator on board the cart 9.

More specifically, the signaling device 11 is a tablet or a laptop screen.

With reference to Figure 2, each maintaining furnace 3 comprises a lid 12 with automatic opening connected to the control unit 5. The control unit 5 is configured to control the opening and the closing of each lid 12.

Moreover, the control unit 5 comprises a memory containing a minimum level 13 and a maximum level 14 of the liquid metal material for each maintaining furnace 3, and an average rate of consumption of the metal material, not shown in the attached figures, for each machine 2 for the die casting.

With reference to Figure 3, a second embodiment of the system 15 for manufacturing metal objects by die-casting a liquid metal material is shown.

The system 15 comprises a conveying assembly 16, configured to feed the liquid metal material to the maintaining furnaces 3 automatically, without the intervention of an operator.

The conveying assembly 16 comprises the ladle 8 and a cart 17 that is self-driven configured to transport the ladle 8 to the maintaining furnaces 3.

The cart 17 that is self-driven comprises a communication device 18 configured to exchange signals with the control unit 5.

In particular, the communication device 18 is configured to receive from the control unit 5 the guidance signals for the supply operations of the maintaining furnaces 3 and to send to the control unit 5 signals indicating the position of the cart 17 that is self-driven.

Moreover, the system 15 comprises a melting furnace 19, which comprises a communication device 20 configured to receive from the control unit 5 the guidance signals for the supply operations of the maintaining furnaces 3 and to send to the control unit 5 signals indicating the state of the melting furnace 19 and of the metal material in the melting furnace 19.

In use and with reference to Figure 1, before the start of the supply operations, the memory is uploaded with data indicating the maximum and minimum levels of each maintaining furnace 3 and the average rates of consumption of each machine 2 for the die-casting.

The liquid metal material is supplied from each maintaining furnace 3 to the associated machine 2 for the die-casting .

In case the level of liquid metal material of at least one of the maintaining furnaces 3 measured by the respective measuring device 4 falls below the minimum level 13 (Figure 2), the control unit 5 emits a consent signal for the supply of the liquid metal material from the melting furnace 6.

Moreover, the control unit 5 emits an indication signal of the maintaining furnace 3 to be supplied associated with the consent signal.

Said consent and indication signals are received by the signaling devices 10 and 11 and are displayed on the screen of the signaling devices 10 and 11, so as to be understandable for the operator in charge of the supply operations . The operator guides the cart 9 so as to position the ladle 8 at the melting furnace 6 and initiates the supply of the liquid metal material from the melting furnace 6 into the ladle 8.

Once the ladle 8 is full of a given amount of liquid metal material, the operator guides the cart 9 so as to position the ladle 8 at the maintaining furnace 3 to be filled signaled by the signaling devices 10 and 11.

In accordance with the preferred embodiment of the present invention, the control unit 5 commands the automatic opening of the lid 12 (Figure 2) of the maintaining furnace 3 to be supplied, for allowing the feeding of the maintaining furnace 3 to be supplied with the liquid metal material contained in the ladle 8.

In accordance with an alternative embodiment of the present invention, the opening of the lid 12 of the maintaining furnace 3 to be supplied is commanded manually by the operator.

In case the sum of the volumes comprised between the maximum level 14 (Figure 2) and the level of the liquid metal material of each maintaining furnace 3 measured by the respective measuring device 4 equals or exceeds the capacity of the ladle 8, the control unit 5 emits the consent signal for the supply of the liquid metal material from the melting furnace 6. Moreover, the control unit 5 emits an indication signal associated with the consent signal, indicating the maintaining furnaces 3 to be supplied and the priority sequence of the supply of the maintaining furnaces 3.

In such case, the melting furnace 6 dispenses an amount of metal material into the ladle 8 such to fill completely the capacity of the ladle 8.

In accordance with a variant of the present invention, the control unit 5 predicts the level of liquid metal material of each maintaining furnace 3 as a function of the average rate of consumption of the associated machine 2 for the die-casting and the level of liquid metal material measured by the respective measuring device 4.

In accordance with such variant, the control unit 5 emits the supply consent signal before the sum of the volumes comprised between the maximum level 14 (Figure 2) and the level of liquid metal material of each maintaining furnace 3 measured by the respective measuring device 4 equals or exceeds the capacity of the ladle 8.

In use and with reference to Figure 3, the system 15 carries out the operations for supplying the maintaining furnaces 3 automatically.

The control unit 5 communicates with the cart 17 that is self-driven via the communication device 18 and initially commands the positioning of the cart 17 that is self-driven at the melting furnace 19.

When the melting furnace 19 receives, via the communication device 20, the supply consent signal emitted by the control unit 5, the melting furnace 19 automatically initiates the supply of a certain amount of liquid metal material into the ladle 8.

When said supply is terminated, the communication device 20 emits an end-supply signal.

The control unit 5 receives the end-supply signal and commands, by sending a movement signal to the communication device 18, the automatic movement of the cart 17 that is self-driven toward the maintaining furnaces 3 to be supplied.

Moreover, the cart 17 that is self-driven provides for the pouring of the liquid metal material from the ladle 8 into each maintaining furnace 3 to be supplied in an automated manner.

In accordance with a variant of the second embodiment, the supply of a given amount of liquid metal material from the melting furnace 19 into the ladle 8 and the pouring of the liquid metal material from the ladle 8 to each maintaining furnace 3 to be supplied occur under the supervision of at least one operator.

Finally, it is evident that variants can be made to the present invention with respect to the described embodiments without thereby departing from the scope of protection of the appended claims.