EP1057562A1

EP1057562A1 - Low pressure casting machine

Info

Publication number: EP1057562A1
Application number: EP99830342A
Authority: EP
Inventors: Alfredo Dal Pan
Original assignee: Fata Group SpA
Current assignee: Fata Group SpA
Priority date: 1999-06-04
Filing date: 1999-06-04
Publication date: 2000-12-06

Abstract

A machine for carrying out a low-pressure casting process in which a pressurized molten casting material is introduced from below into moulds (11) that on their lower side have at least one opening (10) for the introduction of the said casting material. The machine comprises a scaffolding frame (2) for supporting the said moulds (11) and with at least two parts (4, 22) that define respectively a casting station (4) and and an auxiliary station (22). A unit (12) to sustain the said moulds (11) comprises a first (12a) and a second (12b) portion capable of sustaining a pair of the respective moulds (11). The supporting unit (12) is mounted on the scaffolding frame (2) in such a manner as to be capable of rotating around a principal axis (X140) in such a manner as to produce, as a result of the said motion, the alternate and simultaneous passage of the said first (12a) and the said second (12n) portion from the said casting station (4) to the said auxiliary station (22) and viceversa.

Description

The present invention relates to casting machines having the characteristics specified in the preamble of Claim 1. Such machines are currently being referred to as "low-pressure" casting machines.
Low-pressure casting machines have a number of intrinsic advantages over their traditional machines, which include gravity casting machines (where the casting material is simply poured into the moulds) or pressure casting machines (where the casting material is injected into the moulds under the action of the high pressure generated by a piston). One of these advantages, for example, consists of the energy saving that derives from the fact that only a minimal quantity of casting material has to be brought up to melting point without subsequently being incorporated in the casting. Another series of advantages is bound up with the fact that the introduction of the casting material into the mould can be accurately controlled, avoiding the establishment of turbulent flows during the mould-filling process. It is also possible to obtain controlled cooling of the casting, which preferably commences from the upper layers that are more distant from the point or points at which the casting materials enters the mould.
The principal drawback associated with low-pressure casting technique - in the form in which it has hitherto been implemented - is bound up with having to wait while the newly formed casting solidifies inside the mould before the machine can be prepared for a new casting cycle. In fact, it is not possible for the source of the casting material (generally a furnace) to be disconnected from the mould before the casting material introduced into the mould has become re-solidified: if this operation were to be attempted before the solidification of the lower part of the casting (which, to make matters worse, is usually the last to solidify), it could not but cause a certain quantity of the casting material to flow downwards through the opening or openings that served to introduce this material.
In a normal low-pressure casting cycle the casting operation in the true sense of the term, i.e. the filling of the mould with the casting material, will occupy an interval of the order of some tens of seconds (thirty seconds, for example). The subsequent cooling and solidification of the casting may last for several minutes (in purely indicative terms: it may range from about two and a half to five minutes, depending on the size of the casting). The operations that have to be carried out to prepare the machine for the new casting cycle (i.e. opening of the mould, removal of the casting, cleaning of the mould, introduction of any patterns, etc.) may require time intervals of the order of about two and a half minutes. Working in the traditional manner, therefore, the aforesaid time intervals are additive for the purposes of defining the overall duration the casting cycle, and this has a negative effect as regards the overall efficiency of the machine in terms of output per unit time.
The present invention sets out to provide a low-pressure casting machine of the type just specified and such as to offer as its principal advantage the possibility of obtaining a substantially increased productivity, possibly also combined with other advantages connected with the carrying out of the various operations that have to be performed on the mould in order to prepare it for the new casting cycle.
According to the present invention, this scope can be obtained by means of a machine having the further characteristics set out in the claims attached hereto.
The invention will now be described, though purely by way of example and not to be considered limitative in any way, by reference to the attached drawings, where:

Figure 1: shows a general view in side elevation of a casting machine in accordance with the invention,
Figure 2: shows a view in front elevation of the same machine,
Figure 3: shows a bird's eye view of the machine Figures 1 and 2, and
Figure 4: shows a section of the machine along the broken line IV - IV of Figure 1.

The reference number 1 in these drawings is used to indicate the whole of a low-pressure casting machine.
The machine 1 comprises a general scaffolding 2 that consists essentially of a robust structural steelwork frame with a lower portion 3 that, at least in the immediate vicinity of one casting station (indicated as a whole as 4), has the general configuration of a tunnel. All this in such a way as to make it possible for a furnace 6 intended to act as the source of the casting material to be introduced below the casting station 4 and, more particularly, below a base plate indicated by the reference number 5.
In general terms (the realization details are to be considered as known and therefore such as not to call for any detailed description for our present purposes), we are here concerned with a structure comprising a casing 7 (that is normally thermally insulated) with associated heating means (of an electrical type, for example) that make it possible to maintain a certain quantity of casting material (for example: aluminium or light alloy) in a molten state inside the said thermally insulated casing 7.
The furnace 6 is preferably mounted on such motion organs 8 as wheels, rollers, slides, etc., that make it possible for it to be moved selectively to the inside of the tunnel part 3 in the scaffolding 2 in such a way as to bring one or more ducts 9 for supplying the casting material into vertical alignment with the casting station 4. When it is vertically aligned in this manner with the casting station 4, the furnace 6 finds itself in a position in which the supply duct or ducts 9 are aligned with one or more corresponding openings 10 communicating with the lower part of a mould 11 situated at the casting station 4.
At this point (in accordance with criteria that are likewise known and do not therefore have to be described in detail here) lifting means, which are here schematically represented by the jacks 7a or some similar linear actuator devices, make it possible to raise the casing 7 of the furnace and thus causing the casting material supply duct or ducts 9 to penetrate into the opening or openings 10 and to establish conditions in which the or each duct 9 and the respective aperture 10 become tightly jointed and can therefore be used as channel for the introduction of the casting material into the mould 11. All this by making use, for example, of the presence of a sealing ring 90 that surrounds the upper end of the duct 9 and so positioned as to come into contact - as a result of the raising of the casing 7 - with a corresponding gasket 110 (which can be made, for example, of fibrous material capable of resisting the high temperatures that will come into play) surrounding the opening 10.
The mould 11 will preferably consist, once again in a well known manner, of two complementary elements (which are here referred to as the lower part 11a and the upper part 11b), with the further possibility (according to the geometric characteristics of the particular casting to be made) of inserting into the moulds refractory bodies (so-called "patterns") capable of preventing the penetration of the casting material and thus giving rise to corresponding cavities within the casting that is formed around them.
The mould 11 rests on the robust base plate of a rotating support unit 12, which will described in greater detail further on, and is subjected to a downward pushing action that is applied to it by a slide 13. The slide 13 is mounted on a series of uprights 14, 140 forming part of the scaffolding 2 in such a way as to have the said capacity of vertical motion. The motion of the slide 13 is realized by means of an actuator element 15 (which in a typical embodiment will be a fluid jack) that acts between the said slide 13 and a butting or bumper structure 16 likewise mounted on the uprights 14, 140.
The slide 13 acts on the mould (usually at a point situated on the upper part 11b) through one or more contrast elements 13a, each of which constitutes a thrust formation. The slide 13 is also associated with a pick-up structure 130 that can be likened to a clamp capable of grasping the upper part 11b of the mould 11 via the gripping elements 131, the function of which will be described in greater detail further on.
The downward thrust exerted by the slide 13 controlled by the actuator element 15 is transferred onto the mould 11 by the contrast elements 13a . The purpose of this arrangement is to force the mould 11, the lower part 11a of which is provided with the opening or openings 10, towards the base plate 12 and, more particularly, towards the casting material supply duct 9 of the furnace 6, thereby realizing the desired conditions of tight connection between the internal volume of the furnace (casing 7) and the internal casting volume of the mould 11.
The movement of the actuator element 15 is produced as the result of a command given to the processing unit - typically a Programmable Logic Controller (PLC) or a Personal Computer (PC) - that supervises the functioning of the machine 1 as a whole, and therefore also the functioning of all the motor or actuator organs here described.
In case of need, however, the actuator 15 can also be operated in such a way as to slightly raise the upper part 11b of the mould 11, which is retained by the pick-up formation 130 acting through the tightening elements 131. As a general rule, this need will arise whenever there is an interruption of the functioning of the machine 1 as a whole: in these conditions, in fact, it is important to avoid the complete solidification of the casting inside the mould at that moment situated in the casting station 4 with all the problems and difficulties that could derive from this event.
The aforesaid raising movement ensures that the casting will be raised from the lower part 11a of the mould 11 since it will tend to follow the upper part 11b by virtue of the fact that that the solidification process commences at the top and continues downwards, so that the casting is more firmly anchored to this upper part 11b of the mould.
At this point there is brought into operation a further actuator element 17 mounted on the slide 13 and acting - at the point 17a - on an expulsion plate 11c associated with the upper part 11b of the mould 11. All this in such a way as to ensure that the casting will drop back into the lower part 11a, in which the casting will come to rest without being anchored to it.
Low-pressure casting technique provides for the airlike mass that occupies the part of the casing 7 of the furnace 6 situated above the free surface of the casting material in the molten state present within the casing 7 to be pressurized by means of a pumping organ 60. The said pumping organ 60 is selectively controlled in such a manner as to create within the said airlike mass (either air or - especially in the case of casting materials of a particular type, magnesium alloys for example, some inert gas) a pressure level such as to ensure that the casting material will be able to rise (through the duct or ducts 9 that draw from the bottom part of the mass of molten casting material) to within the mould 11. All this with a view to forming within the said mould (as a result of its gradually being filled from the bottom upwards, starting from the opening 10) a cast body realized by means of low-pressure casting.
The term "low pressure" indicates the fact that the pressurization level needed to make the fluid casting material rise to inside the mould 11 is, taken on the whole, rather low, especially when compared to the pressures used in pressure casting techniques. Even though this pressure is rather limited, the fact that ducts 9 of a certain section are needed (to obtain the filling of the moulds 11 in a reasonably short time) ensures that an upward force of considerable magnitude will be acting on the moulds 11 while the casting process is in course. This situation therefore requires the structure to exert (via the slide 13 and the elements associated with it) a firm reaction on the mould 11 that will tend to push it in the opposite direction (i.e. downwardly). The same applies as regards the supporting and lifting elements 7a that force the casing 7 of the furnace 6 towards the opening or openings 10, thereby assuring adequate tightness of the joints.
Even though what has so far been described does not differ very greatly from state-of-the-art low-pressure casting machines, it will readily be appreciated that, taken together, the various elements here presented make it possible to achieve repeated cycles of engagement (in such manner as to form a tight joint) of the casting material supply duct (or ducts) 9 with the corresponding opening or openings 10 provided in the lower part of the mould 11 and its or their subsequent disengagement therefrom, in a particularly simple manner. As soon as the casting phase (the filling of the mould 11 with material furnished from the furnace 6) has been completed and the casting so formed has solidified to a sufficient extent (a condition that is verified - in a known manner - either by allowing a predetermined period of time to elapse and/or by means of temperature signals provided by sensors, not shown, associated with the mould 11), the duct or the ducts 9 can be disengaged from their respective openings 10, thus making it possible for the mould 11 to become displaced with respect to the scaffolding 2 and to move away from the furnace 6.
The aforesaid disengagement motion can be obtained as the result of a relative motion due to the slight raising of the base plate 12 (obviously disengaged from the strong downward thrust exerted by the slide 13).
The base plate 12, which acts as the supporting unit of the moulds, is capable of carrying out the said raising movement relative to the scaffolding 2 by virtue of the fact that it essentially consists of a kind of merry-go-round revolving around a central core or hub 18 mounted on one of the uprights of the scaffolding 2 and indicated 140. Being situated in a central position with respect to the scaffolding 2 (note, in particular the views of Figures 3 and 4), the upright 140 constitutes a kind central column of the this scaffolding.
The hub 18 has an associated actuating element 180 of its own - preferably a fluid jack - that enables it to realize the aforesaid raising motion (and, of course, the complementary downward motion) as an axial sliding motion along the upright 140. The hub 18 is also fitted around the said central upright 140 in such a manner as to permit it to rotate in a controlled manner around a central vertical axis of the machine - indicated X140 - whenever a motor 19 is set in motion: the motor in question is preferably an electric motor and is once again controlled by the PLC unit (not shown in a specific manner on the drawings) that controls in a coordinated manner the various other motor/actuating elements incorporated in the machine. In a preferred solution the motor 19 acts on the hub 18 through a motor reducer unit and a transmission, which could be - for example - a belt or a chain 21.
This solution, be it clear, is not by any means imperative, but is well suited to satisfy the requirement that the hub 18 should be capable of performing both and axial and a rotating motion with respect to the upright 140.
To all intents and purposes (note, in particular, the view of Figure 4), the base plate 12 has a structure that is substantially symmetrical with respect to the axis X140, situated preferably in a barycentric position with respect to the plate 12. The said base plate can therefore be seen as deriving from the bringing together of two bracket-like parts that are capable of symmetrically sustaining two moulds 11 carried by two respective portions 12a and 12b of the base plate 12 and making the said moulds 11 rotate around the axis X140 in accordance with a general merry-go-round layout.
The mould 11 shown in the left-hand part of Figure 1 is likewise made up of a lower part 11a and an upper part 11b and, further, is provided with one or more openings 10 for the introduction of the casting material, each associated with its respective gasket ring 110. Associated with the upper part 11b, the mould is also provided with the expulsion plate 11c.
Once the or each duct 9 for supplying the casting material has been disengaged from its respective opening 10 of a mould 11 in which a newly formed casting has only just solidified, the motor 19 can be activated to make the base plate 12 rotate about the vertical axis X140 (after the plate has been raised along this axis) in such a manner as to bring the two moulds mounted in symmetrical positions on the two parts 12a and 12b of the plate to occupy their respective previous positions.
The mould 11 within which a casting has just been formed (at the casting station 4 shown in the right-hand part of Figure 1) will thus be moved to the other machine station (indicated as a whole by the reference number 22 and shown in the left-hand part of Figure 1), where it can be subjected to the various operations of discharging the newly formed casting and preparing the mould for the next casting cycle.
While this is being done, the rotation of the plate 12 will bring the other mould 11, which has just been prepared for a new casting cycle (at the station 22 and by means of the operations described in the previous paragraph), to occupy the casting position in the casting station 4. Here, after the or each of the duct 9 for supplying the casting material has been made to engage with the respective opening 10 (mainly as the result of a lowering of the plate 12 obtained by causing the hub 18 to slide downwards along the upright 140), the newly arrived mould is used for carrying out a new casting operation.
The station 22 (which will henceforth be distinguished from the casting station 4 by referring to it as the "auxiliary" station) has a structure that is on the whole similar to that of the casting station. It, too, is ideally defined by further uprights 23 that, together with the previously described central upright 140, form a kind of triangular cage, the height of which (for reasons that will be clear further on) is somewhat greater than the height of the cage that defines the casting station 4.
Technicians specialized in the casting sector will readily appreciate that the stanchion structure just described, which consists of five uprights, that is to say, a central upright 140 and two pairs of uprights (respectively 14 and 23) arranged at the vertices of a Saint Andrew's cross, constitutes a choice that is preferential but not imperative for the purposes of implementing the invention.
The preference accorded to this particular structure derives from its intrinsic simplicity, its limited redundancy (since the upright 140 is common to the two stations 4 and 22) and the possibility of conferring upon the stations 4 and 22 (and especially upon the slides 13 and 24 - the latter slide is to be described further on - and their respective reaction structures 16 and 25 - where the latter, once gain, will be described in greater detail in due course) a triangular conformation that is particularly simple, robust and easy to center.
The station 22 comprises the slide 24, which is intended to act on the moulds 11 when they come to be situated in the auxiliary station 22. This slide can move vertically along the uprights 140 and 23 under the action of an appropriate actuator means 26 (preferably, once again a fluid jack) mounted on the reaction structure 25 situated at the top of the stanchions 140 and 23.
Just like the slide 13, also the slide 24 is provided with one or more contrast elements 24a below a tilting device 27, subsequently to be described in greater detail, and a pick-up formation 240 capable of acting on the upper parts 11b of the moulds 11 through their respective gripping elements 241.
When the actuator 26 is appropriately operated, the slide 24 can thus be raised together with the upper part 11b of the mould 11. The latter will bring with it the casting previously in the mould 11 at the casting station 4.
The casting in question can thus be picked up (for example, by means of a manipulator robot not shown in the figures, but of a known type), causing it to become detached from the upper part 11b by means of the plate 11c, which is controlled (at 28a) by its respective actuator 28, which is similar to the actuator 17 previously described in connection with the casting station 4.
It will readily be appreciated that the attachment formations 17a and 28a interposed between the actuators 17 and 28 and the plates 11c of the moulds 11 must be configured in such a way as to render possible the necessary engagement motions following the displacement of the moulds 11, this also in relation to the raising/lowering motion of the plate 12.
A further actuator 30 (preferably constituted - once again - by a fluid jack and preferably acting between the slide 24 and the tilting device 27) makes it possible to selectively impose (usually by means of a command given by an external operator) a general motion of rotation around a horizontal axis X27 upon the tilting device 27 and, more particularly, upon the lower portion of this structure. By means of the formation 240, the said lower portion carries the upper part 11b of the mould 11. The axis X27 and the actuator 30 are usually situated on opposite sides of the tilting device 27 (as can be noted by reference to Figure 2).
Consequently, the extension motion of the actuator 30 will produce an overall bascule motion of the lower part of the tilting device 27 and thus produce a corresponding rotation or bascule motion of the upper part 11b of the mould occupying the auxiliary station 22.
As schematically shown by the broken lines in Figure 2, the result of the said bascule motion is thus that of moving the part 11b towards one of the sides of the scaffolding of the machine and into a position in which the mould is readily accessible - and in conditions of safety - for carrying out any necessary maintenance operations (which may be carried manually and / or automatically). Such operations may become necessary, for example, to remove any casting material residues that may have remained in the mould.
On completion of the operations of removing the casting from the mould and cleaning the empty mould, the mould - by means of a motion complementary to the one that has just been described - can be brought back into the position shown on the left-hand side of Figure 1. In this condition the mould is once again ready for commencing a new casting operation.
At this point, subject to repeating at the proper moment and in accordance with the previously described criteria the various motions of raising/rotating/lowering the plate 12 with respect to the axis X140, it is again possible to obtain:

the displacement from the casting station 4 to the auxiliary station 22 of a mould 11 in which a new casting has just been formed and, simultaneously,
the displacement from the auxiliary station 22 to the casting station 4 of a mould 11 that has been duly prepared for a new casting operation.

While a casting operation (the actual filling of the mould 4 and the subsequent solidification of the newly formed casting) is being carried out at the casting station 4, the solution in accordance with the invention therefore makes it possible for the various operations of removing the newly formed casting from the mould, cleaning the mould and preparing it for the next casting operation (including the insertion into the mould of any necessary patterns or similar auxiliary elements) to be carried out at the auxiliary station 22.
In this way the periods of time needed to perform the casting operation (complete with the time required for the solidification of the casting) and to remove the casting from the mould and prepare the mould for the next casting operation are no longer additive, because the two series of operations, rather than being performed in sequence, are now carried out in parallel.
This makes it possible for the productivity of the machine to be stepped up to vary considerably. The most advantageous solution will of course be obtained in situations in which the operation of casting the piece and allowing it to solidify will call for more or less the same time as is required for removing the casting from the mould in which it was formed and preparing that mould for a new casting operation. In this situation, indeed, the productivity of a machine in accordance with the invention will to all intents and purposes be double that of a machine of the traditional type.
The benefits of the invention are however appreciable even in situations in which the operation of casting the piece and allowing it to consolidate (the latter being usually the phase consuming the greater amount of time) occupies a longer period of time than the one needed to remove the casting from the mould and prepare the mould for a new casting operation.
It will also be appreciated that the solution in accordance with the invention is wholly compatible with the need for periodically reconstituting (by means of state-of-the-art techniques not illustrated) the level of the casting material within the furnace 6 and/or subjecting the furnace 6 to any necessary check-up and maintenance operations. This even when the carrying out of these operations requires the furnace 6 to be withdrawn from its position within the scaffolding 2 of the machine.
In particular, technicians familiar with the sector will readily appreciate that the machine in accordance with the invention can be employed in combination with moulds 11 and a furnace 6 of a state-of-the-art type and therefore in all probability already available at the works of prospective users of the machine.
Naturally, the realization details and the implementation forms can be widely varied with respect to what has here been described and illustrated without in any way altering the principle of the present invention or going beyond its scope as defined by the claims that follow.

Claims

A machine for carrying out a low-pressure casting process in which a pressurized molten casting material is introduced from below into moulds (11) that on their lower side have at least one opening (10) for the introduction of the said casting material, the machine comprising a scaffolding (2) for sustaining the said moulds (11) and accommodating a source (6) of the said casting material, characterized in that the scaffolding (2) comprises at least two parts (4, 22) that define, respectively, a casting station (4) and an auxiliary station (22) with a unit (12) to sustain the said moulds that comprises a first (12a) and a second (12b) portion capable of sustaining a pair of the said moulds (11), where the said supporting unit (12) is mounted on the said scaffolding (2) with the capacity of moving (X140) in such a manner as to produce, as a result of the said motion, the alternate and simultaneous passage of the said first (12a) and the said second (12b) portion from the said casting station to the said auxiliary station and viceversa.
A machine in accordance with Claim 1, characterized in that the said supporting unit comprises essentially a plate (12) that extends in the horizontal direction and is mounted in such a manner as to be capable of rotating around a principal axis (X140) of the scaffolding (2) orientated in a substantially vertical direction.
A machine in accordance with Claim 2, characterized in that the said principal axis (X140) is located in a substantially barycentric position with respect to the said unit (12).
A machine in accordance with any one of Claims 2 and 3, characterized in that the said scaffolding (2) comprises an upright (140) that defines the said principal axis (X140) and the said supporting unit (12) is provided with a hub (18) mounted in such manner as to be capable of rotating around the said upright (140), said hub carrying associated motor means (19 to 21) to control its rotation movements.
A machine in accordance with any one of Claims 2 to 4, characterized in that the said scaffolding (2) comprises an upright (140) that defines the said principal axis (X140) and the said supporting unit (12) is provided with a hub (18) mounted in such manner on the said upright (140) as to be capable of performing an axial sliding motion; the said hub (18) carrying further associated motor means (180) for selectively producing the raising and the lowering of the said supporting unit (12) as a result of the said relative axial sliding motion.
A machine in accordance with any one of the preceding claims, characterized in that it comprises at the said casting station (4) a thrust structure (13) capable of realizing an action that will force the mould (11) from time to time located in the said casting station (4) to move downwards.
A machine in accordance with Claim 7, characterized in that the said thrust structure comprises a slide element (13) mounted in such a manner as to enable it to slide along the said scaffolding (2).
A machine in accordance with Claim 6, characterized in that the said thrust structure (13) carries associated pick-up means (130, 131) capable of gripping at least one part (11b) of the said moulds positioned in the said casting station (4) in order to raise it in a controlled manner with respect to the said supporting unit (12).
A machine in accordance with Claim 8, characterized in that the said thrust structure (13) carries an associated expulsion actuator (17) that, with the said at least one part (11b) of the said moulds (11) positioned in the casting station (4) in the raised position with respect to the said supporting unit (12), is adapted to be activated to produce the expulsion of a respective casting from the said at least one part (11b).
A machine in accordance with any one of Claims 1 to 9, characterized in that the scaffolding (2) at the casting station (4) is configured as a tunnel in order to permit the insertion of a source (6) of the said casting material in position below the said supporting unit (12) of the moulds (11).
A machine in accordance with any one of the preceding claims, characterized in that the said supporting unit (12) carries associated gasketing means (90, 110) capable of realizing a joint that will be tight under pressure and disengageable as and when required between the said at least one opening (10) and the said source (6) of the said casting material.
A machine in accordance with Claim 10, characterized in that the machine comprises the said source (6) of casting material, where the said source (6) has at least one duct (9) for introducing the said casting material into the said moulds through the said at least one aperture (10), and further characterized in that the said gasketing means (90, 110) are associated, at least partly (90), with the said at least one duct (9).
A machine in accordance with any one of the preceding claims, characterized in that the said auxiliary station (22) comprises a pick-up and lifting structure (24) carrying associated respective pick-up means (240, 241) adapted for acting at least one part (15b) of said moulds positioned in the said auxiliary station (22) to cause lifting thereof with respect to said supporting unit (12).
A machine in accordance with Claim 13, characterized in that said pick-up and lifting structure (24) carries an associated respective expulsion actuator (28) that, with the said at least one part (11b) of the said moulds (11) positioned in the said auxiliary station (22) in the raised position with respect to the said supporting unit (12), is adapted to be activated to produce the expulsion of a respective casting from the said at least one part (11b).
A machine in accordance with Claim 13 or Claim 14, characterized in that the said pick-up and lifting structure (24) carries an associated tilting device (27) that has associated with it a respective further actuator elements (30) that, with the said at least one part (11b) of the said moulds (11) positioned in the said auxiliary station (22) in the raised position with respect to the said supporting unit (12), is adapted to be selectively activated to produce the tilting of the said moulds in the said raised position and thus to bring the said moulds (11) into a position where they can be accessed from outside the machine.
A machine in accordance with any one of the preceding claims, characterized in that the said scaffolding (2) comprises a plurality of uprights (14, 140, 23), one of which (140) is located in a substantially central position of the said structure (2), while the other uprights of the said plurality (14, 23) define, together with the said central upright (140), respectively the said casting station (4) and the said auxiliary station (22).
A machine in accordance with Claim 16, characterized in that the said other uprights (14, 23) are arranged in two pairs located at the vertices of a Saint Andrew's cross that has its centre at the said central upright (140).
A machine in accordance with Claim 6 and Claim 17, characterized in that the said thrust structure (13) is of a substantially triangular shape.
A machine in accordance with Claim 13 and Claim 17, characterized in that the said pick-up and lifting structure (24) is of a substantially triangular shape.