CONTINUOUS CASTING FURNACE FOR MELTING NON-FERROUS METALS, IN PARTICULAR FOR JEWELRY MAKING

Abstract

 The present invention relates to a continuous casting furnace (10) for melting non-ferrous metals, in particular for jewellery making, comprising a supporting frame (11) on which there are arranged a melting and casting head (12), a pulling unit (13) for the extraction of a profile (P) descending from said melting and casting head (12), and a cabinet (14), said cabinet (14) containing an electric generator unit (15), a hydraulic cooling unit (16), an inert gas circuit (17), and comprising an electronic control unit (U).
The pulling unit (13) comprises two pairs of shaped drive rollers, respectively a first pair of upper shaped drive rollers (71, 72) and a second pair of lower shaped drive rollers (73, 74), a first upper shaped roller (71) and a first lower shaped roller (73) being mounted on a first horizontally moving slide (75), while the second upper shaped roller (72) and the second lower shaper roller (74) are mounted on a second horizontally moving slide (76), said first slide (75) and second slide (76) being slidable on respective horizontal guides (81, 82) towards and away from each other.

Description

Technical sector

[0001] The present invention relates to a continuous casting furnace for melting non-ferrous materials, in particular for jewellery making.

Background

[0002] The invention relates to the technical sector of melting alloys, in particular for jewellery making, made using the method of "continuous casting".

[0003] Continuous casting furnaces generally produce semi-finished articles in the form of a wire, a bar, a sheet or a tube.

[0004] The invention is intended to prevent any contamination between the various metal alloys with different carat weights and compositions which are introduced into the continuous casting furnace.

[0005] It is nowadays known that the technique of continuous casting melting ensures a very high quality and ductility of the semi-finished alloys for the production of jewellery; generally, the manufacturers of furnaces, following a simple commercial practice, are organized to construct and sell a specific type or model of furnace for each type of profile which the buyer intends producing. The industrial process of metal working has, during the course of its history, undergone improvements in terms of the methods used and the plants which have become increasingly more advanced and sophisticated; over the years the industrial processes for the production and machining of metallic materials have been developed so as to define highly dedicated techniques and technology for the specific compositions of the metal alloys which are to be made and formed. These techniques over the years have resulted in the development of melting furnaces which vary depending on the amount of metal to be melted, and in particular furnaces for processing daily batches and continuous-cycle furnaces are known.

[0006] These growth trends have been of fundamental importance in particular for the jewellery industry, where production has increased from a micro or small scale to large-scale artisanal production on a global and industrial level.

[0007] Nowadays induction furnaces have become increasingly more widespread compared to gas melting furnaces, still used in the poorer less industrialized countries, and electric resistance furnaces.

[0008] The induction furnace is used in particular in foundries where large-size castings are not required, as in the case of gold and gold alloy processing, and where large weights with very small volumes are present; owing to induction furnaces semi-finished articles, such as tubes, sheets and wires, with varying sizes and diameters depending on the user's requirements, are thus obtained and, in particular, the semi-finished articles obtained with continuous casting induction furnaces have very high ductility and quality characteristics compared to any other melting process previously performed manually using cast-iron clamps or ingot moulds. The first continuous casting induction furnaces introduced into the jewellery-making industry just before the 1980s opened up the market opportunities for the various manufacturers first in Italy and then all over the world.

[0009] The continuous casting induction furnaces for melting non-ferrous metals which are known nowadays, although being increasingly more widespread and popular, have a number of drawbacks.

[0010] Typically, a main type of continuous casting induction furnace for jewellery making comprises a supporting frame on which there are arranged a melting and casting head, a pulling unit for the extraction of a profile descending from the melting and casting head, and a cabinet containing an electric generator unit, a hydraulic cooling unit, an inert gas circuit and an electronic control unit. A first drawback is associated with that mentioned above regarding the unique intended use of a furnace model for a specific product.

[0011] Therefore, until now, if a company which produces profiles made of non-ferrous material wishes to produce both a wire, and a sheet, and a tube, or two tubes with different compositions or carat weights, this production company has to acquire three or four complete furnaces, with a consequent multiplication of the costs.

[0012] This problem is associated with the particular structure of the continuous casting induction furnace mainly present today on the market, as mentioned above.

[0013] Nowadays, in order to change the intended use of a same melting and casting head from a first metal alloy to a second metal alloy, or from a first cross-sectional profile of the product to a second cross-sectional profile of the product, complex and delicate operations are required for disassembly of the crucible and the forming base.

[0014] The structural complexity of the continuous casting induction melting furnaces of the known type, as described above, therefore results, for example, in an operation for removal of a forming base which requires great expenditure, in terms of time, at least three hours, as well as labour, since it requires the intervention of an expert operator, with a consequent lack of productivity due to the machine downtime.

[0015] In general, therefore, in the similar furnaces known nowadays, the head is fixed and the assembly consisting of a crucible and a specific die provide a specific profile, for example a wire with a circular cross-section, made using a specific metal alloy, and it is not possible to change quickly the die for the production of a wire with a round cross-section using a different die, for example for the production of a profile defining a rectangular sheet.

[0016] Since nowadays it is necessary to change often also the carat weight - or in in general the composition - of the alloy which is to be used for their specific production, in order to satisfy the increasingly numerous and demanding markets, manufacturers are substantially obliged to acquire several machines with a single head or machines with a fixed double head, in order to cover all the various production needs.

[0017] A second not less significant drawback of these furnaces of the known type is associated with the pulling unit.

[0018] A generic pulling unit usually comprises at least two shaped drive rollers, where "shaped" is understood as meaning that they have an annular recess with a shaped cross-section, which shaped cross-section is configured so as to partially surround the cross-section of the profile formed by the melting and casting head and descending from the head.

[0019] The two drive rollers are arranged with their axes horizontal and parallel, with respect to a normal working condition of a continuous casting induction melting furnace, and are arranged underneath the melting and casting head so that a descending rectilinear profile is gripped between the shaped portions of the shaped drive rollers and is driven and pushed downwards with the application of forces such as to prevent breakages, tearing, stretching or other typical damage.

[0020] Of the two oppositely arranged drive rollers, a first drive roller is motorized and a second drive roller is idle.

[0021] One of the two shaped rollers is generally supported by a bracket which is in turn mounted on the rod of a pushing cylinder, where the pushing cylinder is positioned and configured so as to push the movable shaped roller against the descending profile on one side thereof, while the second opposite side of the same descending profile rests against the fixed shaped roller.

[0022] The main drawback of such a pulling unit is associated with the presence of a single electric motor, which is set up to operate directly a first shaped roller and, if necessary via a chain drive, also the second opposite drive roller.

[0023] A pulling unit with a single motor is not suitable for handling profiles which have different size cross-sections, with major risks of damage to the said metal profile which may be over-pulled or under-pulled, with the consequent risk of tearing of the said profile and subsequent pouring of molten metal from the overlying melting and casting head, or incorrect slowing down of the descent of the metallic material, with the consequent opposite problems of excessive hardening due to over-cooling of the profile which remains for too long in the cooling zone of the melting and casting head.

[0024] Another main drawback is associated with the equilibrium of the pushing forces which are exerted on the profile by the drive rollers, and the centring of the descending profile, which must not be deviated from its straight path when exiting the melting and casting head.

[0025] In fact, since one drive roller is fixed and the other drive roller is movable and is pushed against the descending profile, there is in any case albeit minimum bending of the profile owing to the pushing force generated on one side only, with consequent deviation from the correct straight downward path.

[0026] Moreover, since only one of the drive rollers is motorized, while the other roller is driven by means of a chain drive, there is an albeit minimum difference in the speed of rotation of the two drive rollers, with the result that the profile is pulled on its two opposite sides at different speeds and with different forces.

[0027] A further limitation of the pulling units which have a fixed drive roller and movable drive roller is that associated with the difficulty of modifying the melting and casting head in order to adapt it for the production of a different profile or for the processing of an alloy with a different composition or carat weight.

[0028] In fact, while a movable drive roller may move away from the metal profile which has been formed and is still attached to the melting and casting head after it has been deactivated, the other fixed drive roller remains in contact with the profile formed and an incorrect movement of the cooled and therefore hardened profile may result in damage to the overlying melting and casting head.

Summary of the invention

[0029] The main task of the present invention is to therefore to provide a continuous casting furnace for melting non-ferrous materials, in particular for jewellery making, able to overcome the limitations and drawbacks of the techniques of the prior art.

[0030] In connection with this task, an important object of the invention is to provide a continuous casting furnace which allows rapid change-over of the intended end product, both in terms of the metal alloy used and in terms of the shape of the profile output from the melting head.

[0031] Another object of the invention is to provide a continuous casting furnace which is able to ensure better pulling of the formed metal profile output from the melting and casting head.

[0032] Yet another object of the present invention is to provide a continuous casting furnace in which the formed metal profile does not risk being damaged as a result of deviations from the correct descending path or excessive pulling by the pulling unit or imbalances in the pulling forces.

[0033] The aforementioned task and objects are achieved by a continuous casting furnace for melting non-ferrous materials, in particular for jewellery making, according to claim 1.

[0034] Detailed characteristics of the furnace according to the invention are described in the dependent claims.

[0035] Further characteristic features and advantages will emerge more clearly from the description of a preferred, but non-exclusive, embodiment of the continuous casting furnace for melting non-ferrous materials according to the invention, with the aid of the drawings provided by way of a non-limiting example in the attached illustrations and listed below.

Brief description of the figures

[0036] Reference will be made to the figures of the attached drawings in which:

▪ Figure 1 shows a schematic perspective view of a furnace according to the invention;

▪ Figure 2 shows a side view of the furnace according to Figure 1;

▪ Figure 3 shows a schematic cross-sectioned view of a melting and casting head of the furnace according to the invention;

▪ Figure 4 shows a front view of a pulling unit of the furnace according to the invention in an operating condition;

▪ Figure 5 shows a front view of the pulling unit according to Figure 4 in a non-operating condition;

▪ Figure 6 shows a schematic side view of the pulling unit of the furnace according to the invention;

▪ Figure 7 shows a rear perspective view of the pulling unit of the furnace according to the invention;

▪ Figure 8 shows a schematic front view of the pulling unit in an operating condition;

▪ Figure 9 shows the same view as Figure 8 in a non-operating condition;

▪ Figure 10 shows a partially exploded side view of the furnace according to the invention;

▪ Figure 10A shows a perspective view of the view shown in Figure 10;

▪ Figure 11 is a rear perspective view of the melting and casting head of the furnace according to the invention;

▪ Figure 12 shows a different rear perspective view of the melting and casting head according to Figure 11;

▪ Figure 13 shows a schematic view of the connections between the elements of the head and the units inside the cabinet;

▪ Figures 14 to 19 each show a phase during a process for replacing a first melting and casting head with a second melting and casting head of the furnace according to the invention.

[0037] The thicknesses and curvatures shown in the figures mentioned above must be understood as being purely exemplary and are generally on a larger scale and not necessarily shown in proportion.

Detailed description of preferred embodiments

[0038] Below various embodiments and variants of the invention will be described with reference to the figures mentioned above.

[0039] Similar components are indicated in the various figures by the same reference number.

[0040] In the detailed description which follows, embodiments and variants in addition to those embodiments and variants already considered in the same description will be described only with regard to their differences from that already described.

[0041] Furthermore, the various embodiments and variants described below may be used in combination, where compatible.

[0042] With reference initially to Figure 1, the continuous casing furnace according to the invention is denoted overall by the number 10.

[0043] Said furnace 10 comprises a supporting frame 11 on which there are arranged a melting and casting head 12, a pulling unit 13 for the extraction of a profile P descending from, i.e. formed by, said melting and casting head 12, and a cabinet 14.

[0044] The cabinet 14 contains an electric generator unit 15, a hydraulic cooling unit 16, an inert gas circuit 17 and comprises an electronic control unit U.

[0045] The electric generator unit 15, the hydraulic cooling unit 16 and the inert gas circuit 17 are schematically shown by means of broken-line rectangles in Figure 2 and are to be understood as being of the type known per se.

[0046] The electric generator unit 15, the hydraulic cooling unit 16, the inert gas circuit 17 and the electronic control unit U are to be understood as being positioned outside of the cabinet 14 or inside, or partly outside and partly inside.

[0047] The melting and casting head 12, schematically shown in Figure 3, comprises in turn by way of a non-limiting example:

• a box-like containment body 18, having an upper lid 19 and a bottom 20;
• a crucible 21, said crucible 21 being preferably, but not exclusively made of graphite or another technically equivalent material;
• a ceramic jacket 22 surrounding the crucible 21;
• an airtight chamber 23 defined between the crucible 21 and the ceramic jacket 22 and apt to be filled with inert protection gas;
• a ceramic hatch 24 for loading the metallic material to be melted, resting on the crucible 21 by means of a sealing element 25, the ceramic hatch 24 being configured to pass through the upper lid 19 so as to be available for loading the metallic material to be melted;
• an inductor 26 surrounding the ceramic jacket 22;
• a forming base 27, in the sector also known as a "die", having a shaped through-hole 28 through which the melted metallic material descends towards the underlying pulling unit 13, the forming base 27 being inserted in the lower part of the crucible 21 and extending so as to cross the bottom 22a of the ceramic jacket 22 as far as a descent opening 29 defined on the bottom 20 of said box-like containment body 18;
• means for cooling the inductor 26;
• means for cooling a lower portion 27a of said forming base 27;
• means for detecting the temperature of the crucible 21;
• means for detecting the temperature of the forming base 27.

[0048] The electric generator unit 15 is configured to power the at least one inductor 26.

[0049] The forming base 27, also known as "die", is preferably made of graphite, but it is understood that it may also be made of another similar and technically equivalent material.

[0050] The hydraulic cooling unit 16 is configured to supply said means for cooling the inductor 26 and the means for cooling said lower portion 27a of the forming base 27.

[0051] The inert gas circuit 17 is configured to fill the airtight chamber 23 and the crucible 21.

[0052] The inert gas may be nitrogen or argon, or another similar or technically equivalent protective fluid.

[0053] The pulling unit 13 is, in a known manner, positioned underneath the melting and casting head 12, 12A and 12B.

[0054] The special feature of the present invention consists in the fact that the pulling unit 13 comprises two pairs of shaped drive rollers, i.e. a first pair of shaped drive rollers 71 and 72, or pair of upper rollers, and a second pair of shaped drive rollers 73 and 74, or pair of lower rollers, respectively.

[0055] A first upper shaped roller 71, namely a first roller of the pair of shaped rollers, and a first lower shaped roller 73, namely a first roller of the second pair of shaped rollers, are mounted on a first slide 75, while the second shaped roller 72, namely a second roller of the first pair of shaped rollers, and the second shaped roller 74, namely a second roller of the second pair of shaped rollers, are mounted on a second slide 76; the first slide 75 and second slide 76 are movable along a line perpendicular to the direction in which a formed profile P, namely a descending profile, is output from the melting and casting head 12. For example, the movement line, namely the direction of movement, of the first slide 75 and second slide 76 is substantially horizontal, while the axis Y of descent of the profile P is substantially vertical. "Horizontal" is understood as meaning that it is parallel to a surface on which the furnace 10 rests. This expression therefore has the commonly understood meaning.

[0056] The first slide 75 and the second slide 76 are slidable on respective horizontal guides 81 and 82 away from each other and towards each other.

[0057] The horizontal guides 81 and 82 comprise for example two cylindrical bars, an upper bar and a lower bar, on which both the first slide 75 and the second slide 76 slide.

[0058] The two slides 75 and 76 are moved by symmetrical translation means configured to cause a translation of the two slides 75 and 76, where the translation movements of the two slides 75 and 76 are:

• of the same amount, for example L1 and L2 in a first condition shown in Figure 8, and L3 and L4 in a second condition shown in Figure 9, with respect to a plane passing along an axis Y of descent of a formed profile P, namely a descending profile;
• such that these amounts L1, L2, L3, L4 are measured along a same translation axis X, where said translation axis X is transverse to the plane passing along the axis of descent Y;
• in opposite direction or opposite sense.

[0059] At least one shaped drive roller of each slide is motorized, or at least one shaped drive roller of the two shaped drive rollers 71 and 73 of the first slide 75, namely at least one of the first roller of the first pair of shaped rollers 71 or the first roller of the second pair of shaped rollers 73 mounted on the first slide 75, and at least one shaped drive roller of the two shaped drive rollers 72 and 74 of the second slide 76, namely at least either the second roller of the first pair of shaped rollers 72 or the second roller of the second pair of shaped rollers 74 mounted on the second slide 76, are motorized.

[0060] Preferably and advantageously, each shaped drive roller 71, 72, 73, 74 is driven by a corresponding dedicated gearmotor 71a, 72a, 73a, 74a.

[0061] Each shaped drive roller 71, 72, 73, 74 is mounted on its corresponding first slide 75 or second slide 76 together with the corresponding dedicated gearmotor 71a, 72a, 73a, 74a.

[0062] The symmetrical translation means comprise for example:

• a driving bar 77 comprising a first threaded section 77a intended for the first slide 75 and a second threaded section 77b intended for the second slide 76;
• a first nut 78 integral with the first slide 75 and coupled to the first threaded section 77a;
• a second nut 79 integral with the second slide 76 and coupled to the second threaded section 77b.

[0063] The first threaded section 77a and the first nut 78 are configured to cause the movement of the first slide 75 in a first direction along the translation axis X, and the second threaded section 77b and the second nut 79 are configured to cause the movement of the second slide 76 in the second direction opposite to the first direction along the same translation axis X.

[0064] For example, the symmetrical translation means comprise:

• a threaded driving bar 77 where the first threaded section 77a and the second threaded section 77b are symmetrical with respect to the plane passing along the Y axis;
• a first nut 78 having a first counter-threading with a first orientation, said first nut 78 being located in the first slide 75;
• a second nut 79 having a second counter-threading with a second symmetrical opposite orientation with respect to the first orientation of the first nut 78.

[0065] The threaded driving bar 77 is operated by a manually operated handwheel 80. Alternatively, the threaded driving bar 77 is operated by an electric precision motor.

[0066] The horizontal guides 81 and 82 and the threaded driving bar 77 are mounted inside a structural frame 85 which is in turn fixed to the supporting frame 11 of the furnace structure 10 according to the invention.

[0067] The structural frame 85 consists, for example but not exclusively, of a single-piece aluminium block.

[0068] The first slide 75 and the second slide 76 have a shape with opposite steps which favour their mutual centring when they approach each other towards a working position, as shown by way of example in Figure 8.

[0069] Elastic thrust elements are mounted on the horizontal guides 81 and 82 and ensure the packing closure of the first slide 75 and the second slide 76; these elastic thrust elements are for example calibrated springs, not shown for simpler illustration.

[0070] Such a pulling unit 13 is able to achieve an important advantage associated with the use of four motors, one for each of the drive rollers, since with the four motorized drive rollers it is possible to obtain optimum control of the pulling force on the profile P descending from the melting and casting head 12, preventing tearing and breakage of said descending profile P.

[0071] Furthermore, owing to the symmetrical translation means, rapid and precise symmetrical splaying of the drive rollers is obtained, with the release of the final section of the descending profile P from a melting and casting head 12A, therefore allowing rapid removal of the melting and casting head 12 from the cabinet 14.

[0072] It is to be understood that a pulling unit 13, as described above, as such also forms part of the subject-matter of the invention, as such.

[0073] Said pulling unit 13 can be used in vertical or horizontal continuous casting plants with fixed or quick-change melting heads, for the most varied industrial applications.

[0074] In particular, a furnace structure 10 according to the invention has a preferred application in the sector of fine and costume jewellery, and in general in the sector of fashion accessories, which comprise the manufacture of semi-finished profiles to be extracted from continuous casting, such as round wires, square wires, semi-round wires, rectangular sheets, sheets with particular profiles, for example Ag or "dog bone" anodes, or empty tubes of various sizes. Advantageously the melting and casting head 12 is mounted removably on a support shelf 31 of said supporting frame 11.

[0075] In particular, the melting and casting head 12 has a rear panel 32, which is clearly visible in Figures 11 and 12, facing a correspondingly counter-shaped connection opening 33 defined on said cabinet 14.

[0076] The connection opening 33 allows an operator to access the rear panel 32 from the inside of the cabinet 14, once the cabinet 14 has been opened laterally. The rear panel 32 has:

• first reversible connection means 40 configured to electrically connect said inductor 26 to said electric generator unit 15;
• second reversible connection means 41 configured to hydraulically connect said cooling means of said inductor 26 with said hydraulic cooling unit 16;
• third reversible cooling means 42 configured to connect said means for cooling said lower portion 27a of said forming base 27 either with said hydraulic cooling unit 16 or with an auxiliary hydraulic cooling unit;
• fourth reversible connection means 43 configured to connect said means of detecting the temperature with said electronic control unit U;
• fifth reversible connection means 44 configured to connect said airtight chamber 23 and said crucible 21 with said inert gas circuit 17.

[0077] The airtight chamber 23 is sealed by means of sealing with ceramic silicone.

[0078] In accordance with that already known, a gripping bar 50 is placed inside the shaped through-hole 28 in order to start the descent of the solidifying melted metal.

[0079] The first reversible connection means 40 comprise two electric power cables with terminals for connection to the electric generator unit 15.

[0080] The first reversible connection means 40 also comprise two signal cables 40a. The means for cooling the inductor 26 are also included in the same inductor 26 which is tubular and inside which cooling water flows.

[0081] The second reversible connection means 41 may therefore be hydraulic connection elements of the known type.

[0082] The second reversible connection means 41 comprise two flexible hydraulic tubes.

[0083] The means for cooling the lower portion 27a of the forming base 27, or "die", comprise an annular bushing 51, schematically indicated in Figure 3, in turn surrounded by an annular tubular channel 52 for cooling water.

[0084] The third reversible connection means 42 comprise therefore flexible hydraulic pipes.

[0085] The temperature detection means comprise a first thermocouple 45 for detecting the temperature of the crucible 21 and a second thermocouple 46 for detecting the temperature of the forming base 27.

[0086] The fourth reversible connection means 43 therefore comprise respective electric cables and simple plug-in connectors.

[0087] The inert gas circuit 17 comprises an inert gas cylinder and a corresponding duct for delivery of the inert gas towards the melting and casting head 12.

[0088] The fifth reversible connection means 44 therefore comprise at least one line of pipes configured to introduce the inert gas into the crucible 21 and the airtight chamber 23.

[0089] Advantageously, the first reversible connection means 40, the second reversible connection means 41, the third reversible connection means 42, the fourth reversible connection means 43 and the fifth reversible connection means 44 extend from said rear panel 32 and cross said connection opening 33 towards the inside of said cabinet 14.

[0090] Owing to this special furnace 10 it is possible to replace a melting and casting head 12 with another one by simply disconnecting the aforementioned reversible connection means, said operation being able to be performed by an operator in a rapid and intuitive manner.

[0091] Figures 14 to 19 schematically show in chronological order the main steps in a process for replacing a first melting and casting head 12A with a second melting and casting head 12B having a different forming base or having a new crucible suitable for the melting of an alloy different from that used in the crucible of the first melting and casting head 12A.

[0092] In this non-limiting example of embodiment of the invention, the support shelf 31 comprises two, substantially horizontal, parallel brackets on which a casting and melting head 12, 12A or 12B is transferred by means of frontal displacement or frontal sliding from a support carriage 60 towards the support shelf 31 or, vice versa, from the support shelf 31 towards the support carriage 60.

[0093] Figure 14 shows a first replacement step in which the support carriage 60 is moved towards the furnace 10 having, mounted thereon, a first melting and casting head 12A.

[0094] The support carriage 60 advantageously is substantially symmetrical and carries a second melting and casting head 12B.

[0095] Figure 15 schematically shows a positioning step in which a first support portion of the support carriage 60 is slid between the brackets of the support shelf 31 and the first melting and casting head 12A is disconnected from the cabinet 14 by means of opening of all the reversible connection means.

[0096] Figure 16 schematically shows a step involving the movement away of the support carriage 60 carrying both the first melting and casting head 12A and the second melting and casting head 12B intended to be connected to the cabinet 14 instead of the first melting and casting head 12A.

[0097] Figure 17 shows a step of rotation of the support carriage 60 such as to position the second casting and melting head 12B facing the cabinet 14, where the second melting and casting head 12B is positioned on the support carriage 60 such that the rear panel 32 is directed towards the outside and therefore towards the connection opening 33 defined on the cabinet 14.

[0098] The connection opening 33 is defined opposite the support shelf 31 and above it.

[0099] Figure 18 schematically shows a step involving the transfer of the second melting and casting head 12B from the support carriage 60 onto the support shelf 31 with the consequent introduction of the reversible connection means inside the connection opening 33 and consequent step of performing the connections.

[0100] Figure 19 shows schematically a final step involving the movement away of the support carriage 60 carrying the first melting and casting head 12A which remains available for subsequent use.

[0101] It can therefore be understood how a furnace 10 according to the present invention is able to achieve the predefined objects and task.

[0102] In particular, the present invention provides a continuous casting furnace which allows rapid changing of the intended end product, both in terms of the metal alloy used and in terms of the shape of the profile output from the melting and casting head 12.

[0103] Moreover, the invention provides a continuous casting furnace which is able to ensure better pulling of the formed metal profile output from the melting and casting head 12.

[0104] Furthermore, the present invention provides a continuous casting furnace 10 in which the formed metal profile does not risk being damaged as a result of deviations from the correct downward path or excessive pulling by the pulling unit 13 or imbalances in the pulling forces.

[0105] Furthermore, the present invention provides a continuous casting furnace which allows the small-size manufacturer to have only one induction generator, but with the possibility of using two or more different melting and casting heads 12, 12A, 12B, thus cutting costs in a very significant manner.

[0106] With the present invention it has been therefore possible to provide a furnace which avoids the forced replacement of the aforementioned parts, eliminating the risks of damage and the long machine downtime required for changes in the intended final use.

[0107] The invention thus devised may be subject to numerous modifications and variations, all of which fall within the scope of protection of the attached claims. Moreover, all the details may be replaced by other technically equivalent elements.

[0108] Where the operational characteristics and the techniques mentioned in the following claims are followed by reference numbers or symbols, these reference numbers or symbols have been assigned with the sole purpose of facilitating understanding of the said description and claims and consequently they do not limit in any way the interpretation of each element which is identified, purely by way of example, by said reference numbers or symbols.

Claims

1. Continuous casting furnace (10) for melting non-ferrous metals, particularly for jewellery making, comprising a supporting frame (11), on which there are arranged a melting and casting head (12), a pulling unit (13) for the extraction of a profile (P) descending from said melting and casting head (12), and a cabinet (14), said cabinet (14) containing an electric generator unit (15), a hydraulic cooling unit (16), an inert gas circuit (17), and comprising an electronic control unit (U), characterized in that said pulling unit (13) comprises two pairs of shaped drive rollers, respectively a first pair of shaped drive rollers (71, 72) and a second pair of shaped drive rollers (73, 74), a first shaped roller of said first pair of rollers (71) and a first shaped roller of said second pair of rollers (73) being mounted on a first horizontally moving slide (75), while the second shaped roller of said first pair of rollers (72) and the second shaped roller of said second pair of rollers (74) are mounted on a second horizontally moving slide (76), said first slide (75) and second slide (76) being slidable on respective horizontal guides (81, 82) towards and away from each other.

2. Furnace according to claim 1, characterized in that said two slides (75, 76) are moved by symmetrical translation means configured to cause a translation of the two slides (75, 76), where the translation movements of the two slides (75, 76) are:

- of the same amount with respect to a plane passing through an axis (Y) of descent of a descending profile (P),

- where these amounts are measured along the same translation axis (X), where this translation axis (X) is transverse to said plane passing through the axis (Y) of descent,

- in opposite directions or opposite senses.

3. Furnace according to one or more of the preceding claims, characterized in that at least one shaped drive roller of each slide is motorized, or at least one shaped drive roller of the two shaped drive rollers (71, 73) mounted on the first slide (75) and at least one shaped drive roller of the two shaped drive rollers (72, 74) mounted on the second slide (76) are motorized.

4. Furnace according to one or more of the preceding claims, characterized in that each shaped drive roller (71, 72, 73, 74) is driven by a corresponding dedicated gearmotor (71a, 72a, 73a, 74a).

5. Furnace according to one or more of the preceding claims, characterized in that each shaped drive roller (71, 72, 73, 74) is mounted on its corresponding first slide (75) or second slide (76) together with the corresponding dedicated gearmotor (71a, 72a, 73a, 74a).

6. Furnace according to one or more of the preceding claims, characterized in that said symmetrical translation means comprise:

- a driving bar (77) comprising a first threaded section (77a) intended for the first slide (75) and a second threaded section (77b) intended for the second slide (76),

- a first nut (78) integral with the first slide (75) and coupled to the first threaded section (77a),

- a second nut (79) integral with the second slide (76) and coupled to the second threaded section (77b),

said first threaded section (77a) and the first nut (78) are configured to cause the movement of the first slide (75) in a first direction along the translation axis (X), and the second threaded section (77b) and the second nut (79) are configured to cause the movement of the second slide (76) in the second direction opposite to the first direction along the same translation axis (X).

7. Furnace according to one or more of the preceding claims, characterized in that said threaded driving bar (77) is operated by a manually operated handwheel (80).

8. Furnace according to one or more of the preceding claims, characterized in that said horizontal guides (81, 82) and the threaded driving bar (77) are mounted inside a structural frame (85) which is in turn fixed to the supporting frame (11) of said furnace (10).

9. Furnace according to one or more of the preceding claims characterized in that said first slide (75) and said second slide (76) have a shape with opposite steps which favours their mutual centering when they approach each other towards a working position.

10. Furnace according to one or more of the preceding claims, characterized in that elastic thrust elements are mounted on said horizontal guides (81, 82) and ensure the packing closure of the first slide (75) and the second slide (76), said elastic thrust elements being for example calibrated springs.

Drawing