EP3237130A1

EP3237130A1 - Mould for elements of bimetal radiators and related method

Info

Publication number: EP3237130A1
Application number: EP15820270.5A
Authority: EP
Inventors: Piera CALVI
Original assignee: OMC Srl
Current assignee: OMC Srl
Priority date: 2014-12-22
Filing date: 2015-12-03
Publication date: 2017-11-01
Also published as: EA033255B1; EA201791403A1; WO2016103086A1

Abstract

A mould is described for producing modular elements of bimetal radiators, i.e. which are provided with an insert constituting the steel inner core and an aluminium radiant outer coating. The mould is designed for making the modular elements by die- casting, and is constituted by two mould halves that can be closed one against the other in order to negatively define the cast or impression to produce. Advantageously, with respect to known solutions the mould of the present invention differs by having four casts or impressions rather than the conventional two, and a retaining system to retain the metal inserts on board of the same mould half provided with the system for ejecting the modular elements. This allows automating the moulding process and doubling the productivity.

Description

"MOULD FOR ELEMENTS OF BIMETAL RADIATORS

AND RELATED METHOD"

***

DESCRIPTION

Field of the Invention

The present invention relates to a mould for modular elements of bimetal radiators, in particular a mould compatible with automated and unmanned production cycles, and claims the priority of the Italian Patent Application n. 102014902318366 (BS2014A000216).

State of the Art

As is well known, the radiators (also named heaters) are mainly constituted by a plurality of assembled modular elements, i.e. bonded one to another - in series - in order to achieve the desired radiant surface. Each radiator element is hollow inside in order to define a duct for the circulation of hot water fed by the system for heating the environment in which the radiator is positioned.

Due to its inalterability to external agents, light weight and good heat exchange qualities, in the last years the market rewarded the use of aluminium as a material for producing radiators. In practice, radiator manufacturers produce the modular elements by the technique of die-casting aluminium in proper moulds.

The aluminium is injected speedily and pressurized in a closed mould that defines the cast, also named impression, of the modular element of the radiator.

Typically the mould is constituted by two mould halves of special steel, which material has a melting point higher than the aluminium; a mould half is stationary, i.e. fixed and does not move, the other mould half is movable with respect to the fixed mould half between a closed position and an open position. In the closed position the two mould halves are in abutment one against the other, just to define the cast/impression of the modular element, and in the open position the two mould halves are separated and the workers can move between them, meaning that the area between the two separated mould halves has to be accessible in order to enable the operations provided by the production cycle to take place. During the production, when the mould is closed, the injection pressure of the molten aluminium is maintained for the whole duration of the moulding process until the solidification of the produced element occurs.

The mould temperature is controlled and adjusted by means of a proper system for circulating a cooling liquid inside the two mould halves. In particular, the cooling system comprises ducts obtained inside the mould halves; the ducts are connected to a set of outer - computerized - control units controlling the inflow of the cooling liquid depending on whether they have to remove or transfer heat. The cooling liquid is pressurized water and/or diathermal oil.

Once the so made modular element solidifies in the mould, the latter is opened and the modular element is extracted; a new moulding cycle can thus start.

For example, the following Youtube video shows a conventional process for manufacturing aluminium modular elements: https://www.youtube.com/watch?v=qAyJx8x3KuI.

However, in some areas of the world water exhibits corrosive features that can cause the degradation over time of the radiator aluminium elements during their normal operation for heating environments. For example, this problem is felt in some areas of Russia and China.

Therefore, so called 'bimetal' radiators have been provided whose modular elements are provided with an inner steel core or other corrosion resistant alloy, and an aluminium outer coating. The steel core defines itself the duct for circulation of hot water. This solution allowed overcoming the problem of corrosive waters; in fact, when the radiator is in use, water does not contact the aluminium any more, but remains confined in the circuit defined by the set of steel cores of all the modular elements.

The following documents describe the known art in the field of die-casting of modular elements of bimetal radiators: CN 203508941(U), CN 203565828(U), EP-A- 0816791 and RO 117481(B).

Presently, the moulds used for producing the bimetal modular elements comprise a maximum of two casts, i.e. they are designed for making two modular elements at every moulding cycle. For example, US 3,439,732 describes a mould with two impressions, i.e. able to produce two modular elements at a time. A similar solution is described also in documents CN-A-1810414 and CN 2880325Y.

Both in single-impression moulds and in moulds with two impressions, the previously produced steel core is positioned in the mould before the respective closing, so that it its then incorporated in the aluminium. In particular the steel core is anchored to the stationary mould half, the latter for this reason comprising pins for temporary retaining the steel core.

More specifically, the steel core is constituted by a vertical pipe whose ends are joined to two horizontal bushings, and for this reason it is frequently defined as type H insert.

The Applicant found that a limitation of present moulds is just due to the limited number of bimetal modular elements that can be produced in the time unit.

As things stand now, moulds with more than two impressions are not available. The reason is due to worker safety and the execution speed in positioning and locking the inserts in the stationary mould half.

In fact, workers have to move between the two open mould halves during the time interval between two consecutive moulding cycles, in order to manually position the inserts in the stationary mould half. The area comprised between the two open mould halves is dangerous due to both high temperature of the two mould halves and the movable mould half being handled by a large press along a direction intercepting just the area in which workers operate. It is therefore convenient that workers remain in this area for the shortest possible time and a mould with more than two impressions is so large to make difficult or even impracticable the worker operations without the aid of specific equipment. So this is why it has been observed over time that having more than two impressions would force the workers to remain in the dangerous area for an excessive period of time; furthermore, the two open mould halves would cool down excessively if the workers were forced to operate for a long time in order to prearrange the inserts for more than two impressions.

In practice, in order to obtain the desired productivity, presently heater manufacturers operate several moulds in parallel, and each mould has one or two impressions.

Summary of the Invention

Object of the present invention is therefore to provide a mould for modular elements of bimetal radiators that allows overcoming the limits of the today available solutions, thus resulting usable in automated production cycles, in order to obtain higher productivity without impairing the workers safety.

It is a further object of the present invention to provide a mould for modular elements of bimetal radiators that is provided with one, two or more than two impressions, compatible with automated systems for loading the inserts when the mould is open.

The present invention relates therefore to a mould according to claim 1 for producing bimetal modular elements of hot-water radiators.

In particular the mould comprises a stationary mould half, named by the field technicians fixed mould half, and a movable mould half.

The movable mould half can be displaced with respect to the fixed mould half between a closed position, at which the two mould halves are in abutment one against the other, and an open position, at which the two mould halves are far one from another.

In the closed position the two fixed and movable mould halves negatively define at least one cast or impression of modular element intended to be filled with molten and pressurized aluminium speedily fed by external means. In practice, the cast or impression is a recess corresponding to the volume to be filled with the molten aluminium. Obviously, each cast is partially excavated in the fixed mould half and partially in the movable mould half.

At least one of the two mould halves, and preferably the movable mould half, comprises means for retaining a metal insert, for example a steel insert, intended to remain included in the aluminium in order to define a duct for the circulation of hot water in the respective modular element. The metal insert will constitute the core of the completed radiator, resistant to corrosive waters.

The mould further comprises ejecting means to eject the moulded bimetal modular elements; the ejecting means are intended to intervene when the mould is open in order to detach the modular elements from one of the mould halves.

Preferably, the ejecting means comprise a plurality of ejecting pins to eject the solidified modular elements in the mould. The ejecting pins are translatable in corresponding seats in the mould in a direction transverse to the casts, i.e. are retractable; when activated, they cantileverly come out from the mould half thereby pushing out the modular element until then stuck in the mould half, then causing the detachment thereof. The seats of the ejecting pins open just near the casts/impressions, so that when the pins are extended the respective ends push the solidified modular elements out of the casts.

With respect to the known art the mould according to the present invention differs because the means for retaining the metal inserts and the ejecting means are on the same mould half, preferably the movable one.

One of the advantages achieved by this configuration is the possibility of completely automating the moulding cycle also when the mould is provided with several casts or impressions. The loading of the metal inserts in the mould and the taking of the moulded modular elements can occur automatically thanks to a robotic loading and unloading system, as an industrial manipulator.

Retaining the modular elements on the mould half provided with the ejecting means makes unloading the modular elements very easy without the risk of the same modular elements remaining stuck in one of the mould half. This feature makes automation possible for the operations with a robotic arm moving in the area between the two open mould halves, in place of the workers conventionally employed in this step of the moulding cycle.

A robotic arm is therefore programmable in order to speedily carry out the just described operations, without the risk of the arm striking against the ejecting system of the mould, just because such a system is always on the opposite side of the arm with respect to the moulded modular elements.

From still another point of view, the configuration of the mould according to the present invention is advantageous since it ensures that the modular elements remain all constrained to the same mould half when the mould opens, also when the mould is provided with several casts/impressions. For example, if the mould is provided with four casts/impressions for the simultaneous production of as many modular elements, at the mould opening the four modular elements all remain constrained to the same mould half, and not some on a mould half and others on the other mould half, just because the retaining means are on board of the same mould half.

Preferably the mould is provided with a plurality of casts/impressions of modular elements, and more preferably it is provided with four casts and not of only two.

It has to be emphasized that in the past moulds with four casts have been proposed to produce modular elements of radiators by die-casting method, but in that case it was always a case of not bimetal radiators, but exclusively made of aluminium, i.e. free of means for retaining the steel inserts. Apparently, a technical prejudice popular among mould manufacturers has made a mould with four casts to be deemed not feasible for bimetal modular elements. The reason has been explained in relation to the known art: in case of moulds with four casts/impressions, the residence time of the workers in the area between the two open mould halves, for loading the inserts and unloading the modular elements, would be too long and would imply risks to safety.

However, by considering the advantages provided by the present invention, the problem of worker safety can be solved by using a robotic arm. The present invention makes thus possible the use of several casts/impressions, even four, for the benefit of productivity.

Preferably, the casts/impressions are side by side and parallel in the mould. In tests carried out by the Applicant, this configuration proved to be the best as for the bulk minimization and the possibility of effectively adjusting the mould temperature. Alternatively, the mould can be produced with the casts arranged radially around the aluminium inlet point, but in this case the mould would have much larger size and its temperature would be more difficult to adjust. In addition, also the after-casting handling would be complex and economically detrimental.

In the closed position the two fixed and movable mould halves define a distribution channel of the molten aluminium in the casts of the modular elements. The distribution channel in its turn comprises four arms, or branches, each of which distributes the aluminium to a corresponding cast of the four casts in the mould. The channels have geometries specifically sized to make the aluminium get to the four casts in the right times, thus obtaining a high quality production. Preferably, two branches extend between a first and a second cast immediately adjacent thereto, and the other two branches extend between the third and the fourth cast adjacent to the fourth cast. In other words, the casts are pairwise grouped and the branches of the aluminium distribution channel do not extend between the second and the third cast.

For its side the steel insert can be simply a pipe with folded ends, or more commonly a pipe connected at its ends to two transverse bushings (either threaded or not) that will constitute the holes connecting the modular elements one with another.

In the preferred variation of the mould the means to retain the steel insert are pins. As mentioned, it is preferred to provide the movable mould half with the pins to retain the inserts. In particular, the pins have to be configured to retain the steel inserts and prevent them from falling before the mould closes and moving in the mould during the injection of the molten aluminium. In addition, the pins have to retain the moulded modular elements, when the mould opens, and prevent them from falling before the robotic handling system takes them for their delivery to the next work station provided in the production cycle.

The just described result is preferably obtained by providing the pins with at least one portion cantileverly extending from the respective mould half and with a shape complementary with respect to the corresponding part of the metal inserts with which it has to interact, whether it is a bend or a bushing. In practice when an insert is fitted on the pins, the latter penetrate at least partially in the inserts, in the holes obtained in the bushings or bends, until a sufficient interference between the pin and the metal insert is obtained.

Referring to the instance of the inserts with bushings, a robotic arm pushes the inserts onto the pins until the bushings become anchored on the same due to the so- created interference. It is just this interference that ensures the inserts and the modular elements not falling incidentally when the mould is open. The pressure applied by the robotic arm can be adjusted in order to obtain such a result. The interference should also allow extracting the modular elements from the mould.

Preferably, the portion of the pins with which the interference is created is a cylindrical portion whose outer diameter corresponds to the inner diameter of the insert bushings. More preferably, the pins are provided with a conical end serving for driving the insertion of the metal inserts into the bushings.

If also the other mould is provided with pins, the latter will not have the function of retaining the inserts and the modular elements, just because the latter are desired to always remain on the same mould half, but they will rather act as insert countercheck surface when the mould is closed, in order to obtain the correct centering.

Preferably, a centre-to-centre comprised in the interval 350-800 mm is defined between the pins.

Preferably, the centre-to-centre between the retaining pins of the radiator is selected from:

350 mm, and the corresponding centre-to-centre provided in the mould will have to be between 349 mm and 352 mm, to take account of the tolerances;

500 mm, and the corresponding centre-to-centre provided in the mould will have to be between 499 mm and 502 mm;

600 mm, and the corresponding centre-to-centre provided in the mould will have to be between 599 mm and 602.50 mm;

700 mm, and the corresponding centre-to-centre provided in the mould will have to be between 699 mm and 703 mm;

800 mm, and the corresponding centre-to-centre provided in the mould will have to be between 799 mm and 803.50 mm.

In the preferred embodiment of the present invention a sleeve wraps each pin, so as to be coaxial with the same and telescopically movable. In practice, the sleeve is a cylindrical element slidingly fitting to the pins. The sleeves are movable with respect to the pins between a rearward position and a forward position. The actuator is preferably hydraulic and even more preferably it is the same actuator of the ejecting means, such as for example a dedicated hydraulic circuit.

In the rearward position, the sleeves do not interact with the inserts or the modular elements. When the mould is closed, but before the molten aluminium is injected, the sleeves are pushed towards the forward position to compensate for possible clearances and move in abutment against the bushings or bends of the metal inserts, that de facto are in this way firmly pressed between the same sleeves and corresponding countercheck surfaces of the other mould half, for example other pins with whom they do not interlock.

This feature also promotes the automation of the loading of the inserts in the mould, since possible small positioning errors made by a robotic arm are compensated by the intervening sleeves that inevitably force the inserts in the correct position.

When the sleeves are pushed and held in abutment against the inserts, a seal preventing the aluminium from penetrating in the inserts through the holes of the bushings or bends is obtained. This is a significant advantage since the rejections are avoided.

The sleeves also work as ejecting means, since as the mould is opened they can be operated together with the ejecting pins, aiding them in ejecting the moulded modular elements from the mould half. In this instance the sleeves push the inserts outwardly, and the whole modular element with them.

The Applicant found that, in order to more easily adjust the mould temperature both in the start step and in the steady state condition, the mould is usefully designed with determined distances among the casts, so that the heat transferred by the molten and pressurized aluminium speedily injected into the mould can be distributed or removed with the highest efficiency. In particular the distance between a first and a second cast, and between a third and a fourth cast, is preferably comprised in the range 50-100 mm and the distance between the second and the third cast is comprised in the range 100-200 mm.

The mould comprises a cooling circuit constituted by a plurality of canalizations obtained in the two mould halves in their inside and fed with a cooling liquid, for example water or diathermal oil, circulated by a series of external electronic control unit. Preferably, canalizations and flow rates of the cooling liquid are configured for:

- preheating the mould halves before initially starting the die-casting process, named start-up;

- during the start-up step, removing heat from the two fixed and movable mould halves in the areas comprised between a first and a second cast immediately adjacent thereto, and between a third and a fourth cast adjacent thereto and heating the remaining areas of the two mould halves, to prevent lack of temperature balance that could cause the two mould halves to be not in the same plane;

- in a steady state condition during the die-casting process, removing heat from the two mould halves in the areas comprised between a first and a second cast adjacent thereto and between a third and a fourth cast adjacent thereto and recirculating the cooling fluid in the remaining areas of the two mould halves in order to maintain a constant thermal regime among the parts and to manage to obtain the desired size of the moulded modular elements, after the shrinkage of the steel and aluminium, especially as regards the sizes of the centre-to-centre of the same elements (i.e. the distance among the bushings of the inserts).

The Applicant points out that the design of the internal circuits used for regulating the temperature of the bimetal mould with four impressions is strictly bound to the step of cold implementation of the centre-to-centre of the mould, the hot operation thereof and the subsequent cooling of the moulded bimetal modular elements that, after their ejection from the mould, being subjected to different shrinkages however have to be equally sized. The dimensional accuracy of the bimetal element mostly depends on the size of cold implementation of the centre-to-centre and on the thermal control of the mould.

Preferably, in the steady state condition, the overall flow rate of the cooling liquid circulating in the canalizations is comprised in the range from the minimum of 90 liters per minute to a maximum of 220 liters per minute.

The present invention, in a second aspect thereof, relates to the method according to claim 17 for producing modular elements of radiators. Short list of the figures

Further characteristics and advantages of the invention will be more evident by the review of the following specification of a preferred, but not exclusive, embodiment illustrated for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

- figure 1 is a perspective view of the movable mould half of a mould according to the present invention;

- figure 1 A is a perspective view of a hot-water radiator obtained by assembling aluminium modular elements;

- figure IB is an enlarged view of a portion of the movable mould half;

- figure 1C is a perspective and enlarged view of a steel insert constrainable to the mould according to the present invention to remain included in an aluminium modular element;

- figure 2 is a perspective view of the stationary (fixed) mould half of a mould according to the present invention;

- figure 3 is a cross sectional view of the movable mould half;

- figure 4 is a cross sectional view of the stationary mould half;

- figure 5 is a cross sectional view of the movable mould half;

- figure 6 is a schematic view of the movable mould half, showing the logic of the cooling system;

- figures 7 and 8 are perspective views of the movable mould half in corresponding configurations;

- figure 9 is a front view of a detail of the mould according to the present invention and a steel insert;

- figure 10 is a perspective and enlarged view of some components of the mould according to the present invention, in a first configuration;

- figure 11 is a perspective and enlarged view of the components shown in figure 9, but in a second configuration.

Detailed Description of the Invention

Figure 1 is a perspective view of the movable mould half 1 of a mould according to the present invention. The movable mould half 1 comprises four cast halves or impression halves A, B, C and D, each of which corresponds to a cast/impression half on the fixed mould half 2 shown in figure 2, respectively A', B', C and D'. All the cast halves are recesses excavated in the material of the corresponding mould half 1 or 2.

When the movable mould half 1 is in closed position on the fixed mould half 2, the eight cast halves define together four casts A+A', B+B', C+C, D+D', i.e. the sum of volumes.

Each cast A+A', B+B', C+C and D+D' constitutes the negative of a modular element of the hot water radiator. Figure 1A shows an example of radiator and by the referral 101 a modular element thereof is denoted.

In general the mould can comprise one, two or more casts, but the variation shown in the figures, provided with four casts A+A', B+B', C+C, D+D', is the preferred one since it constitutes the best trade-off among production and operation costs and the productivity offered.

In order to obtain bimetal modular elements 101, the mould is configured for housing steel inserts 200 intended to remain included in the aluminium that will define the modular element 101.

In the example shown in figure 1, the steel inserts 200 are each constituted by a pipe 201 extending in longitudinal direction and two transverse bushings 202 connected to the ends of the pipe 201. The steel inserts 200 define together what will be the future duct for the circulation of hot water in the radiator 100.

The inserts 200 are also visible in figure IB, and in particular figure 1C is a perspective and enlarged view of an insert 200. In figure 1C it can be seen that the bushings 202 are threaded; in general, however, the bushings can also be not threaded initially if the heater manufacturer prefers to carry out the threading at a later time after the modular elements have been extracted from the mould.

Preferably, as shown in the figures, the four casts A+A', B+B', C+C and D+D' are positioned parallel one to another, each extending in longitudinal direction.

In particular, the casts A+A', B+B', C+C and D+D' are grouped two by two, with the casts A+A', B+B' forming a first group and the casts C+C and D+D' forming a second group. The distance, i.e. the centre-to-centre, between the two groups is longer than the distance between the two casts of a same group. In particular, the distance between the first cast A+A' and the second cast B+B' and the distance between the third cast C+C and the fourth cast D+D' is comprised in the range 50-100 mm; the distance between the second cast B+B' and the third cast C+C is comprised in the range 100- 200 mm.

This configuration shown to be optimal for the prearrangement of an effective cooling circuit comprising a plurality of canalizations 3 extending in the two movable 1 and fixed 1 mould halves, for the circulation of a cooling liquid, water and/or diathermal oil. The canalizations 3 are all connected with six external control units (or three having double circuit), not shown, that adjust the flow rates and the temperatures of the cooling liquid, as it will be explained in the following.

Another feature can be well seen in figure IB. It is the configuration of the distribution channel 5 of the molten aluminium in the casts A+A', B+B', C+C and D+D'. The channel 5 is split in two from the starting inlet point of the aluminium into the mould and then again in four branches 51-54.

The branches 51-54 of the distribution channel 5 of the aluminium are also grouped two by two, as the casts. In particular, the branches 51 and 52 are adjacent one to another and extend between the first and the second casts A+A', B+B', whereas the branches 53 and 54 are adjacent one to another and extend between the third and the fourth casts C+C and D+D' .

The distribution channel 5 of the aluminium does not extend between the second cast B+B' and the third cast C+C. This configuration is useful in order to hold the molten aluminium for a sufficient time, i.e. to prevent it from cooling too speedily before reaching the distal ends of the casts with respect to the inlet end.

Figures 3 and 4 are longitudinal transverse sections, respectively of the movable mould half 1 and fixed mould half 2. In these figures the canalizations 3 of the cooling circuit are clear and extend inside the respective mould half 1 or 2 in order to distribute the cooling liquid where needed.

In addition, in the figures 3 and 4 the following components are depicted: the case K also called bolster, the die-holder element P, and the male die M. These elements are provided in both the fixed mould half 2 and the movable mould half 1. The cast halves A-D and A'-D' are obtained in the male die M.

Figure 5 is a cross section of the movable mould half 1 taken on a plane transverse to the cast halves A-D. With the reference 6 the ejecting pins of the modular elements 101 solidified in the mould are denoted. The ejecting pins 6, also named movable strip-like plugs, are slidable in corresponding seats obtained in the movable mould half 2, transversely to the plane containing the cast halves A-D. When the mould is opened, i.e. the movable mould half 1 is moved away from the fixed mould half 2, the bimetal modular elements, now solidified, are ejected by pushing the ejecting pins 6 completely into the respective seats, until coming out and biasing the modular elements until separation from the cast halves A-D.

The ejecting pins 6 are preferably hydraulic, meaning that the thrust making them partially come out from the respective seats is provided by a pressurized liquid, for example pressurized oil in a proper hydraulic circuit.

Figure 6 shows a top plan view of the mould half 1. The areas 7 and 8 inside the dotted lines correspond to a configuration of the cooling circuit partly defined by the canalizations 3, studied for removing heat. In other words, the cooling circuit is studied for removing heat from the areas 7 and 8 (the cooling liquid removes heat from the two mould halves 1 and 2 in these areas) and redistributing it as much evenly as possible in the remaining areas of the two mould halves 1 and 2.

This configuration allows the mould halves 1 and 2 remaining in the same plane during the steps of initial start of the die-casting production process. On the contrary, when the process is in the steady state condition, the cooling circuit continues removing heat from the areas 7 and 8, but in the remaining of the mould the cooling liquid is recirculated.

In reference again to figures 3 and 4, with the numeral reference 4 the pins being on the movable mould half 1 are denoted and with the numeral reference 4' the pins being on the fixed mould half 2 are denoted. Each pair of pins 4 and 4' cooperates in order to temporary retain a bushing 202 of the steel insert 200 during the injection of the molten aluminium in the mould. As it can be noted also observing the figures 1, IB, 4 and 7, in each cast half A-D of the movable mould half 1 there are two retaining pins 4, one for each bushing 202 of the steel insert 200 and in each cast half A-D' of the fixed mould half 2 there are corresponding pins 4'.

Figure IB is an enlargement of figure 1, that shows the area of the movable mould half 1 where the casts A-D are provided. In this figure, the pins 4 can be seen well and the respective retaining function of the bushings 202 of the inserts 200 is evident.

In practice when the mould is closed, i.e. when the two mould halves 1 and 2 are moved in abutment one against the other, the pins 4 and 4' retain in position the inserts 200 that would otherwise be displaced by the aluminium reaching the impressions A-D at a high speed.

Differently from conventional moulds, wherein the inserts are usually retained on the fixed mould half by means of magnetic pins, in the mould according to the present invention the inserts 200 are retained by the pins 4 on the movable mould half 1.

According to the present invention, in fact, the pins 4 and the pins 4' have a different geometry; the differences have been studied by the Applicant in order to obtain the assurance that, even after the solidification of the modular elements 101 and the opening of the mould, the modular elements 101 are still constrained to the movable mould half 1 and not to the fixed mould half 2. Only at a later time, as described afore in reference to figure 5, the ejecting pin 6 operate to separate each modular element 101 from the movable mould half 1.

Figure 8 shows well this concept. The movable mould half 1 is viewed in perspective, with all the ejecting pins 6 projecting from the mould half 1.

In reference to figure 9, the operation of the pins 4 and 4' will be now explained in detail.

The pins 4' of the fixed mould half 2 are stationary, just screwed to the fixed mould half 2 at a shank 9. The portion 10 projecting inwards of a cast/impression is substantially conical. In figure 9 the taper is accentuated for the sake of clarity, but in practice the taper of the portion 10 is to the minimum. The maximum diameter of the conical portion 10 of the pins 4' is such that a press fit occurs with the corresponding bushings 202 of the inserts 200 when the mould is closed. As mentioned afore, the insert 200 has to remain anchored to the movable mould half 1 and therefore the interference created among the bushings 200 and the pins 4' should not be excessive and mainly serves to prevent the molten aluminium from penetrating in the inserts 200 at the threads 203. This situation should not occur since otherwise the obtained modular element 101 would result a reject.

Note that the shank 9 of the pins 4' comprises a portion 9' having larger diameter than the diameter of the bushings 202 of the inserts 200; in this way, when a bushing 202 of an insert 200 is in abutment against the portion 9' of the pins 4', a seal preventing the molten aluminium from penetrating in the inserts 200 is obtained.

The pins 4 of the movable mould half 1 are fastened to the movable mould half 4 with a shank 11 and, therefore, are integral with the same. The shank 11 also acts as limit element for the bushings 202 of the inserts 200, meaning that the shank 11 constitutes a step against whom the bushings 202 move in abutment.

Differently from the pins 4', the pins 4 comprise a cylindrical portion 12 extending between the shank 11 and an almost conical end 13; the latter is the part of the pins 4 visible in the other accompanying figures. In the example shown in the figures, the end 13 has a nick 14, i.e. a flat portion intended to face the pipe 201 of the insert 200 at the joint with the bushing 202 but defining a gap with the same.

The conical end of the pins 4 has more or less the same taper as the end 10 of the pins 4', but since the pins 4 are also provided with the cylindrical portion 12 they make a more effective seal with the bushings 202, meaning that when the mould is opened and the two mould halves 1 and 2 are separated, the bushings 202 of all the inserts 200 are still retained on the pins 4 just by the interference generated with the respective cylindrical portions 12.

Advantageously, the mould comprises a plurality of sleeves 15 that can be partially telescopically extracted from the movable mould half 1, by sliding on the shank 11 of the pins 4. The sleeves 15 are thus sliding in proper seats and have an inner diameter corresponding to the outer diameter of the shank 11 of the pins 4 such to move in abutment head to head against a corresponding bushing 202 of an insert 200, clearly at the side of the movable mould half 1.

In figure 9 the sleeve 15 is shown just in abutment against the bushing 202 of the insert 200 and makes a seal with the same. In this case, the molten aluminium can not penetrate inside the bushing 200.

The telescopic movement of the sleeves 15 can be better comprised by observing figures 7 and 8 sequentially. In particular, in figure 7 the sleeves 15 can not be seen since completely recessed in the respective seats; the conical portions 13 of the pins 4 are visible instead. In figure 8 the sleeves 15 can be seen completely extracted from the respective seats and cantileverly projecting from the movable mould half 1; in the same figure, also the extracted ejecting pins 6 can be seen.

The sleeves 15 are two per each of the four casts A+A', B+B', C+C and D+D', i.e. one per each of the pins 4.

From the preceding description it is therefore evident that the sleeves 15 are movable between a retracted position, at which the conical portions 12 and the cylindrical portion 12 are free to receive a bushing 202 of an insert 200 so that it fits completely, and a forward position at which the sleeves 15 are in abutment against the bushing 202 and apply on the same a pressure adequate to seal against the penetration of the molten aluminium in the insert 200.

Preferably, the movement of the sleeves 15 is actuated by a hydraulic system as the one used for moving the ejecting pins 6. More preferably, the hydraulic system is the same for the ejecting pins 6 and the sleeves 15, meaning that it is shared.

Figures 10 and 11 show in detail the assembly comprising the pins 4' and the pins 4; for sake of clarity these elements are shown separate, i.e. not inserted in the remaining of the movable mould half 1. With the reference 16 a hydraulic actuator having the task of moving the sleeves 15 is denoted. The group formed by the elements 12, 13, 15 and 16 can be defined "sleeve ejector" in technical language. In particular, in figure 10 the sleeves 15 are shown in the rearward position; in figure 11 instead, the sleeves 15 are in abutment against the bushings 202 of the corresponding inserts 200. As it can be noted, on the movable mould half 1 there are two pins 4 per each insert 200.

The operation of the pins 4 and 4' will be now explained in reference to figures 1, IB, 2, 9-11.

A moulding cycle starts with the mould open. Usually in this step the area between the two mould halves 1 and 2 is occupied by a worker manually inserting an insert 200 in the fixed mould half; in the mould according to the present invention instead, the operation of inserting the inserts 200 is completely automated, meaning that industrial manipulators as robotic arms can be used, and it preferably occurs on the movable mould-half 1.

Therefore, we consider the case of a robotic arm drawing four inserts at the same time from a starting station and arranging them on the pins 4 of the fixed mould half 1, rather than one at a time. As explained above, the inserts 200 remain in place on the pins 4 by the interference created between the inner surface of the bushings 202 and the outer surface of the cylindrical portions 12 of the pins 4. At this point, the robotic arm clears the area between the two mould halves 1 and 2 and the mould is closed. The just mentioned interference ensures the inserts 200 not moving while the movable mould half 1 closes against the fixed mould half 2.

When the mould is closed, the portion 10 of the pins 4 of the stationary mould half 2 is inserted in the bushings 202 of the corresponding inserts 200 so as to face the portions 13 of the pins 4, as shown in figure 9.

Advantageously, in order to regain the clearances both among the pins 4, 4' and the bushings 202 of the inserts 200 and obtain the seal against the molten aluminium penetration, before the aluminium is injected in the casts A+A', B+B', C+C and D+D' the sleeves 15 are pushed against the bushings 202 so as to compress the latter against the portion 9' of the pins 4', exactly in the configuration shown in figure 9.

At this point the molten aluminium is injected, in order to obtain the modular elements 101 with the steel core.

At a later time, when the aluminium is solidified, the mould is opened. For the reasons explained afore, bound to the geometry of the pins 4 and 4', the four modular elements 101 are certainly still constrained to the movable mould half 1 during the mould opening.

At this point, the four modular elements 101 are extracted from the movable mould half 1 by activating the ejecting pins 6 and simultaneously also the sleeves 15, as shown in figure 8. The modular elements 101 are drawn from the same robotic arm that initially inserted them in the mould half 1; it is evident that the moulding cycle can de facto become totally automatic thanks to the ejecting pins 6 and the pins 4 being on the same mould half 1. Loading the inserts 200 in the same mould half (in this case the movable one 1) from which the modular elements 101 are extracted allows greatly simplifying the plants, and in particular allows minimizing the intervention of the robotic arm and optimizing the movements thereof.

The four modular elements 101 are thus sent to the next work station provided for their production cycle and the mould is ready for a new moulding cycle.

The great advantage provided by the mould according to the present invention is just of allowing the total automation of the moulding cycle, for the benefit of the worker safety. A significant increase of the productivity can thus be obtained, which could not be obtained by using moulds having several impressions, but with labour for loading the inserts 200.

It is then evident that adopting the sleeves 15 sliding with respect to the ends 13 of the pins 4 of the movable mould half 1 allows canceling the risk that the molten aluminium can penetrate in the inserts 200 during the moulding.

Claims

1. A mould of bimetal modular elements (101) of hot-water radiators (100), comprising a stationary mould half (2), named fixed mould half, and a mould half (1) movable with respect to the fixed mould half (2) between a closed position and an open position, wherein the two mould halves (1, 2) in the closed position negatively define at least one cast or impression (A + A) of a modular element (101) which is intended to be filled with molten aluminium fed from external means, in which at least one (1) of the two mould halves (1, 2) comprises retaining means (4) to retain a metal insert (200), for example a steel insert, intended to be included in the aluminium in order to define a duct for the hot-water circulation in the respective modular element (101), and in which at least one (1) of the two mould halves (1, 2) comprises ejecting means (6) to eject the moulded bimetal modular elements (101),

characterized in that the retaining means (4) are provided on the same mould half in which the ejecting means (6) are provided, in order to allow the complete automation of the operations for loading the metal inserts (200) and unloading the moulded bimetal modular elements (101), without labour aid.

2. Mould according to claim 1, wherein the retaining means (4) and the ejecting means (6) are provided on the movable mould half (1), and the retaining means (4) temporarily retain the moulded modular elements (101) to prevent them from falling once the mould is open.

3. Mould according to claim 1 or claim 2, wherein the casts or impressions are four (Α+Α', Β+Β', C+C and D+D') and are preferably placed side by side and parallel in the mould.

4. Mould according to claim 3, wherein in the closed position the two mould halves (1, 2) define a distribution channel (5) of the molten aluminium in the casts (Α+Α', Β+Β', C+C and D+D') of the modular elements (101), and wherein said distribution channel (5) comprises four branches (51-54), each of which distributes the aluminium to a corresponding cast (Α+Α', Β+Β', C+C and D+D') of the four casts that are in the mould, and wherein two branches (51, 52) extend between a first (Α+Α') and a second (Β+Β') cast and two branches (53, 54) extend between the third (C+C) and the fourth cast (D+D').

5. Mould according to any one of the preceding claims 1-4, wherein said retaining means (4) are pins (4) provided with at least one portion (12) cantilevering from the respective mould half (1) and having complementary shape with respect to a corresponding bushing (202) of an insert (200), so that each bushing (202) fitted on a pin (4) forms with the same a press fit sufficiently effective to ensure the corresponding modular element (101) remaining on the pin (4) at the opening of the mould and such to allow an external handling system taking the modular element (101) by detaching it from the pins (4).

6. Mould according to claim 5, wherein each insert (200), named type H insert, comprises a vertical pipe (201) whose ends are joined to two horizontal bushings (202), and the portion (12) cantilevering from the movable mould half (1) and having a complementary shape with respect to a corresponding bushing (202) of the insert (200) is a cylindrical portion (12) of the pin (4) whose outer diameter corresponds to the inner diameter of said bushing (202).

7. Mould according to any one of the proceeding claims 5-6, wherein each pin (4) further comprises a conical end (13) whose function is to drive the insertion of the pin (4) into the bushing (202) of an insert (200).

8. Mould according to claim 7, wherein the conical end (13) is provided with a nick (14) intended to face the vertical pipe (201) of an insert (200) fitted on the pins (4), and to define a gap with the same.

9. Mould according to any one of the preceding claims 5-8, wherein the pins (4) are two for each cast or impression (Α+Α', Β+Β', C+C and D+D'), and wherein preferably a centre-to-centre is defined between the pins (4) and is comprised in the range 350-800 mm.

10. Mould according to any one of the preceding claims 5-9, comprising for each pin (4) a sleeve (15) telescopically sliding between a rearward position and a forward position.

11. Mould according to claim 10, wherein each sleeve (15) is externally and coaxially fitted to the respective pin (4), preferably around a shank (11) of the pin (4) screwed in the respective mould half (1), and is translatable between the rearward position, at which the sleeve (15) does not project from the respective mould half (1), and a forward position, at which the sleeve (15) cantilevers from the respective mould half (1) for:

- aiding the ejecting means (6) in order to separate the moulded modular elements (101) from the respective mould half (1), and

- canceling the possible clearance between the sleeve (15) and the corresponding bushing (202) of an insert (200), by abutting head to head against the bushing (202) itself, so that a seal is obtained that prevents the molten aluminium from penetrating into the insert (200).

12. Mould according to any one of the preceding claims 10-11, wherein the sleeves (15) are actuated by a hydraulic actuator, preferably shared with the ejecting means (6).

13. Mould according to any one of the preceding claims 1-12, comprising a cooling circuit constituted by a plurality of canalizations (3) obtained in the two mould halves (1, 2) and fed with a cooling liquid, for example water or diathermal oil, circulated by six external control units, in which the canalizations and the flow rates of the cooling liquid are configured for:

- preheating the mould halves before the initial start of the die-casting process, named start-up;

- during the start-up step, removing heat from the two mould halves in the areas (7, 8) comprised between a first (Α+Α') and a second cast (Β+Β') adjacent thereto and between a third (C+C) and a fourth cast (D+D') adjacent thereto and heating the remaining areas of the two mould halves (1, 2) to prevent a lack of temperature balance that could cause the two mould halves (1, 2) to be not in the same plane;

- in a steady state condition during the die-casting process, removing heat from the two mould halves (1, 2) in the areas (7, 8) comprised between a first (Α+Α') and a second cast (Β+Β') adjacent thereto and between a third (C+C) and a fourth cast (D+D') adjacent thereto and recirculating only the cooling fluid in the remaining areas of the two mould halves (1, 2), in order to maintain a constant thermal regime between the parts and to manage to obtain the desired size of the moulded modular elements, after the shrinkage of the steel and aluminium.

14. Mould according to claim 13 wherein, in the steady state condition, the overall flow rate of the cooling liquid circulating in the canalizations is comprised in the range from the minimum of 90 liters per minute for each control unit, to a maximum of 220 liters per minute for each control unit.

15. Mould according to any one of the preceding claims 1-14, wherein the ejecting means (6) are ejecting pins (6) of the modular elements (101) solidified in the mould, said ejecting pins (6) being translatable in the mould in a direction transverse to the casts (Α+Α', Β+Β', C+C and D+D') until cantilevering, when the mould is open.

16. Mould according to any one of the preceding claims 1-15, wherein the mould half (2) not provided with retaining means (4) is also provided with other pins (4') whose function is not to vertically support the modular elements (101) when the mould is open, but rather to act as counter check surfaces, and wherein the metal inserts (200) are pressed between the retaining element (4) and the other pins (4') when the mould is closed.

17. A method for making bimetal modular elements (101) of hot water radiators (100) comprising:

a) providing a mould according to any one of the preceding claims 1-16;

b) when the mould is open, prearranging a metal insert (200) in each cast or impression (Α+Α', Β+Β', C+C and D+D'), by constraining the same to the respective retaining means (4) by means of a robotic handling system;

c) closing the mould by moving the two fixed (2) and movable (1) mould halves in abutment one against the other, by compressing the metal inserts (200) between them;

d) injecting molten aluminium in the mould so as to include the metal inserts

(200);

e) opening the mould and taking the moulded bimetal modular elements (101) with the robotic handling system, by actuating also the ejecting means (6) in order to facilitate the detachment.

18. Method according to claim 17, wherein the retaining means are pins (4) provided on one of the two mould halves (1, 2), preferably on the movable mould half (1), and the step b) is carried out by fitting bushings (202) of said metal inserts (200) on the corresponding pins (4) until obtaining a press fit.

19. Method according to claim 17 or claim 18, wherein the mould further comprises for each pin (4) a sleeve (15) coaxially fitted externally to the respective pin (4) and telescopically sliding between a rearward position and a forward position, and comprising the further step, intermediate between the steps c) and d), of:

f) canceling the possible clearance between the metal insert (200) and the sleeve (15) by moving the latter in abutment head to head against a corresponding bushing (202) of the metal insert (200), so that a seal is obtained that prevents the molten aluminium from penetrating into the insert (200).