ITTV940036A1

ITTV940036A1 - PROCEDURE AND EQUIPMENT FOR THE INJECTION MOLDING OF PARTS IN THERMOPLASTIC MATERIAL.

Info

Publication number: ITTV940036A1
Application number: IT94TV000036A
Authority: IT
Inventors: Ernesto Benvenuto
Original assignee: Nordica Spa
Priority date: 1994-03-28
Filing date: 1994-03-28
Publication date: 1995-09-28
Also published as: ITTV940036A0; IT1274343B

Description

"PROCEDIMENTO ED ATTREZZATURA PER LO STAMPAGGIO AD INIEZIONE -TC/6264/sb DI PARTICOLARI IN MATERIALE TERMOPLASTICO" "PROCEDURE AND EQUIPMENT FOR INJECTION MOLDING -TC / 6264 / sb OF DETAILS IN THERMOPLASTIC MATERIAL"

R I A S S U N T O SUMMARY

La presente domanda ha per oggetto un procedimento ed una attrezzatura atta a consentire lo stampaggio ad iniezione di particolari in materiale termoplastico. The present application relates to a process and equipment suitable for allowing the injection molding of parts made of thermoplastic material.

Tale struttura comprende due distinti iniettori e almeno un giraforme composto da un corpo centrale girevole su un primo asse al quale sono girevolmente associate, su secondi assi distinti dei precedenti, almeno tre forme. This structure comprises two distinct injectors and at least one turntable composed of a central body which can rotate on a first axis to which at least three shapes are rotatably associated on second axes which are distinct from the previous ones.

Tale soluzione consente di ridurre le fasi di stampaggio componenti plastici quando il processo prevede una doppia iniezione riducendo al contempo lo spazio fis ico dell'attrezzatura nell'ambito dello stabilimento. This solution makes it possible to reduce the phases of molding plastic components when the process involves a double injection, at the same time reducing the physical space of the equipment within the plant.

DESCRIZIONE DESCRIPTION

La presente domanda ha per oggetto un procedimento ed una attrezzatura atta a consentire lo stampaggio ad iniezione di particolari in materiale plastico, in particolare quando il processo prevede la doppia iniezione. The present application relates to a process and an equipment suitable for allowing the injection molding of details in plastic material, in particular when the process provides for double injection.

Oggi giorno sono note presse composte da un singolo plastificatore il quale inietta predisposte materie termoplastiche in corrispondenza di uno stampo in cui risulta -posizionabile una predisposta forma. Nowadays presses are known which are composed of a single plasticizer which injects suitable thermoplastic materials into a mold in which a suitable shape can be positioned.

E' noto a tal fine utilizzare un giraforme il quale risulta essere essenzialmente costituito da un singolo asse centrale radialmente al quale sporgono ad esempio tre forme; tale numero consente di ridurre i tempi di lavorazione in quanto una prima forma viene utilizzata per l'iniezione di materie termoplastiche, la-seconda viene poi posta in una camera di post-raffreddamento e la terza subisce l'estrazione del prodotto. For this purpose it is known to use a shapeshifter which is essentially constituted by a single central axis radially from which, for example, three shapes protrude; this number makes it possible to reduce processing times as a first form is used for the injection of thermoplastic materials, the second is then placed in a post-cooling chamber and the third undergoes the extraction of the product.

Nel caso sia richiesta l’effettuazione di una doppia iniezione, sia per conseguire una variazione di colore che per una differenziazione di materiale, è quindi noto utilizzare due presse del tipo precedentemente descritto disposte contrapposte tra loro. If a double injection is required, both to achieve a color variation and to differentiate the material, it is therefore known to use two presses of the type described above arranged opposite each other.

Tra tali presse risulta usuale porre due o più forme corrispondenza di una tavola rotante. Between such presses it is usual to place two or more shapes corresponding to a rotary table.

Ε' anche noto disporre tali due presse non contrapposte tra loro ma in modo che tra le stesse intercorra un angolo minore di 180°, le forme essendo comunque poste radialmente ad un singolo albero centrale rotante. It is also known to arrange these two presses not opposite each other but in such a way that there is an angle of less than 180 ° between them, the molds being in any case placed radially to a single central rotating shaft.

E' anche noto disporre le due presse in parallelo tra loro associando la o le forme da utilizzare a predisposti mezzi per il trasporto delle medesime alla prima e alla seconda pressa. It is also known to arrange the two presses in parallel with each other by associating the last or shapes to be used with suitable means for transporting them to the first and second press.

In genera l e tut ta t ale tecn i ca nota presen t a degl i inconvenienti tra i quali si può essenzialmente segnalare , soprattutto qualora si voglia realizzare una doppia,iniezione, il· grande spazio dalle stesse occupato per il numero di presse coinvolto. In general, all known technical problems present disadvantages among which it is essentially possible to point out, especially if a double injection is to be made, the large space occupied by the same for the number of presses involved.

In secondo luogo le forme, rotanti su un singolo albero centrale, richiedono una movimentazione ad ogni ciclo di iniezione elevando i tempi di realizzazione dei prodotti. Secondly, the molds, which rotate on a single central shaft, require movement at each injection cycle, increasing the production times of the products.

Compito principale di quanto forma oggetto della presente domanda è quindi quello di eliminare gli inconvenienti di cui alla tecnica nota citata escogitando una attrezzatura per lo stampaggio ad iniezione di particolari in materiale termoplastico che permetta di conseguire la doppia iniezione presentando al contempo una notevole riduzione, rispetto alla tecnica nota, dello spazio necessario da destinarsi nello stabilimento. The main task of what forms the subject of the present application is therefore to eliminate the drawbacks of the aforementioned prior art by devising an equipment for injection molding of parts in thermoplastic material which allows to achieve the double injection while presenting a considerable reduction compared to to the known art, of the space necessary to be allocated in the plant.

Nell'ambito del compito sopra esposto un altro importante scopo è quello di realizzare una attrezzatura che permetta incrementare la produzione di particolari in materiale termoplastico presentanti una doppia iniezione. Within the scope of the aforementioned aim, another important object is to provide an equipment which allows to increase the production of details in thermoplastic material having a double injection.

Ancora uno scopo è quello di realizzare una attrezzatura che alle caratteristiche precedenti accomuni quella di risultare strutturalmente semplice. Another object is to provide an equipment which associates with the preceding characteristics that of being structurally simple.

Non ultimo scopo è quello di ottenere una attrezzatura che risulti affidabile e sicura nell'uso. Not least object is to obtain an equipment which is reliable and safe in use.

Il compito e gli scopi sopra accennati,nonché altri che più chiaramente appariranno in seguito, vengono raggiunti da una attrezzatura per lo stampaggio ad iniezione di particolari in materiale termoplastico comprendente due distinti iniettori, che si caratterizza per il fatto di comprendere almeno un giraforme composto da un corpo centrale girevole su un primo asse a cui sono girevolmente associate, su secondi assi distinti, almeno tre forme, e procedimento che si caratterizza per il fatto di comprendere almeno due fasi di iniezione di un primo colore o di un primo tipo di materiale in una di dette forme e di un secondo colore_o di un secondo tipo di materialè'in un’altra di dette forme intervallate da fasi in cui a dette almeno tre forme e corpo centrale viene imposta una rotazione oraria o antioraria atta a consentire il posizionamento delle volute tra dette forme in detta pressa e l'estrazione della o delle rimanenti forme. The above mentioned aim and objects, as well as others which will appear more clearly later on, are achieved by an equipment for injection molding of parts in thermoplastic material comprising two distinct injectors, which is characterized in that it comprises at least one turntable composed of a central body rotatable on a first axis to which at least three shapes are rotatably associated on second distinct axes, and a process which is characterized in that it comprises at least two injection phases of a first color or a first type of material in one of said shapes and of a second color or of a second type of material is in another of said shapes interspersed with phases in which a clockwise or counterclockwise rotation is imposed on said at least three shapes and central body suitable to allow the positioning of the scrolls between said molds in said press and the extraction of the remaining mold or forms.

Ulteriori caratteristiche e vantaggi del trovato risulteranno maggiormente dalla descrizione dettagliata di due particolari,ma non esclusive, forme di realizzazione, illustrate a titolo indicativo e non limitativo nelle allegate tavole di disegni in cui: Further characteristics and advantages of the invention will become clearer from the detailed description of two particular, but not exclusive, embodiments, illustrated by way of non-limiting example in the attached drawings in which:

la fig. 1 illustra, in una vista laterale schematica, una prima forma realizzativa; fig. 1 illustrates, in a schematic side view, a first embodiment;

la fig. 2 illustra, in una vista dall'alto schematica, la soluzione di cui alla figura precedente; fig. 2 illustrates, in a schematic top view, the solution of the previous figure;

le figg. 3, 4 e 5 illustrano, in un particolare, le forme a loro volta girevolmente associate al giraforme; figs. 3, 4 and 5 show, in a detail, the shapes in turn rotatably associated with the turntable;

la fig.6 illustra, in una vista analoga a quella di fig.1, una ulteriore forma realizzativa; Fig. 6 illustrates, in a view similar to that of Fig. 1, a further embodiment;

la fig.7 illustra, in una vista analoga a,quella.di fig.2, la soluzione di cui alla figure precedente; Fig. 7 illustrates, in a view similar to that of Fig. 2, the solution of the previous figures;

le figg.8, 9 e 10 illustrano, in una vista analoga a quella delle figg. 3, 4 e 5, la movimentazione delle forme girevolmente associate al giraforme. Figures 8, 9 and 10 show, in a view similar to that of Figs. 3, 4 and 5, the movement of the molds rotatably associated with the turner.

Con riferimento alle figure precedentemente citate si è indicata con il numero 1 la attrezzatura per lo stampaggio ad iniezione di particolari in materiale termoplastico, quali ad esempio degli scafi. With reference to the aforementioned figures, the number 1 indicates the equipment for injection molding of details in thermoplastic material, such as for example hulls.

Tale attrezzatura comprende almeno un primo iniettore 2 ed un secondo iniettore 3 disposti affiancati tra loro ed atti a iniettare del voluto materiale termoplastico del colore desiderato in corrispondenza di un predisposto stampo montato entro la pressa 4. This equipment comprises at least a first injector 2 and a second injector 3 arranged side by side and able to inject the desired thermoplastic material of the desired color in correspondence with a suitable mold mounted inside the press 4.

A costituire l'attrezzatura concorre un giraforme 5 composto da un corpo centrale 6 girevole su un primo asse 7 di un pri albero 8. The equipment is constituted by a form-turning 5 composed of a central body 6 rotating on a first axis 7 of a first shaft 8.

Il corpo centrale 6 presenta prime appendici che , nella forma realizzativa illustrata, sono in numero di tre disposte circa a 120° tra loro ed indicate con i numeri 9a , 9b e 9c. The central body 6 has first appendages which, in the illustrated embodiment, are three in number arranged at approximately 120 ° to each other and indicated by the numbers 9a, 9b and 9c.

Tali prime appendici presentano una forma essenzialmente t ri angol are in corrispondenza de l cui verti ce ri sul tano girevolmente associate, in corrispondenza di secondi assi 10a, 10b e 10c, una prima forma Ila, una seconda forma llb e una terza forma Ile. Said first appendages have an essentially angular shape in correspondence with the vertices of which are rotatably associated, in correspondence with second axes 10a, 10b and 10c, a first form 11a, a second form 11b and a third form 11a.

L'utilizzo della attrezzatura per lo stampàggio ad iniezione di particolari in materiale termoplastico comprendente il primo iniettore 2 ed il secondo iniettore 3 è quindi il seguente preliminarmente si segnala come ciascuno di detti primo e secondo iniettore può eseguire un ciclo della doppia iniezione ad esempio per l'ottenimento di particolari con colori o materiali diversi. The use of the equipment for injection molding of parts in thermoplastic material comprising the first injector 2 and the second injector 3 is therefore the following preliminarily, it should be noted that each of said first and second injector can perform a double injection cycle, for example to obtaining details with different colors or materials.

Nella prima fase, illustrata in fig. 3, ad esempio in corrispondenza del primo iniettore 2 viene iniettato un primo colore in corrispondenza della prima forma Ila nel mentre il secondo iniettore 3 inietta un secondo colore in corrispondenza della seconda forma 11b. In the first phase, illustrated in fig. 3, for example at the first injector 2 a first color is injected at the first shape 11a while the second injector 3 injects a second color at the second shape 11b.

Il procedimento prevede quindi l'apertura della pressa e una rotazione di 120° in senso antiorario della prima forma Ila intorno al secondo asse 10a e contemporaneamente una pari rotazione in senso orario della terza forma 11c attorno al secondo asse 10c cosi da posizionare la prima forma Ila e la terza forma in corrispondenza del medesimo piano, come illustrato m fig. 4, Successivamente il procedimento prevede una rotazione di 120° del corpo centrale 6 atta a posizionare in corrispondenza della pressa 4 la prima forma 11a e la terza forma 11c e, contestualmente, l'estrazione della seconda forma llb dalla pressa stessa, come indicato nella fig. 5. The procedure therefore provides for the opening of the press and a rotation of 120 ° counterclockwise of the first form 11a around the second axis 10a and at the same time an equal clockwise rotation of the third form 11c around the second axis 10c so as to position the first form 11a and the third form in correspondence of the same plane, as illustrated in fig. 4, Subsequently, the procedure provides for a rotation of 120 ° of the central body 6 able to position the first form 11a and the third form 11c in correspondence with the press 4 and, at the same time, the extraction of the second form 11b from the press itself, as indicated in the fig. 5.

In questo caso, ad esempio, è possibile effettuare una seconda iniezione in corrispondenza della prima forma 11a ed una prima iniezione in corrispondenza della terza forma 11c. In this case, for example, it is possible to carry out a second injection at the first shape 11a and a first injection at the third shape 11c.

Per quanto concerne la seconda forma 11b questa,-a regime,·-aveva già subito una prima iniezione a partire dalla condizione illustrata in fig. 3 risultando quindi, nella condizione illustrata in fig.5, pronta per lo scalzamento del prodotto cosi ottenuto. As far as the second form 11b is concerned, this one, at steady state, had already undergone a first injection starting from the condition illustrated in fig. 3 resulting therefore, in the condition illustrated in fig. 5, ready for the stripping of the product thus obtained.

Le fasi così schematizzate nella realtà potranno essere contestuali, ossia le rotazioni delle forme attorno ai rispettivi secondi assi e del corpo centrale attorno al primo asse potranno avvenire contemporaneamente. The phases thus schematized in reality can be contextual, ie the rotations of the shapes around their respective second axes and of the central body around the first axis can take place simultaneously.

Oppure la successione potrà essere diversa, avendosi prima la rotazione del corpo centrale e poi la rotazione delle singole forme,pur restando nel medesimo concetto inventivo. Or the succession could be different, having first the rotation of the central body and then the rotation of the individual shapes, while remaining in the same inventive concept.

Si è così constatato come il trovato abbia raggiunto il compito e gli scopi prefissati essendosi conseguita una attrezzatura che permette di conseguire lo stampaggio iniezione di particolari in materiale termoplastico con doppi iniezione la quale richiede uno spazio assai contenuto nello stabilimento risultando al contempo elevata la produzione dato che, a regime, nel mentre viene effettuata la doppia iniezione può essere scalzato dalla forma un prodotto su cui tale doppia iniezione è già stata effettuata. It has thus been found that the invention has achieved the intended aim and objects, having achieved an equipment which allows to achieve the injection molding of parts in thermoplastic material with double injection which requires a very limited space in the factory while at the same time high production given. that, when fully operational, while the double injection is carried out, a product on which this double injection has already been carried out can be removed from the mold.

Naturalmente il trovato è suscettibile di numerose modifiche e varianti, tutte rientranti nell'ambito del medesimo concetto inventivo. The invention is naturally susceptible of numerous modifications and variations, all of which are within the scope of the same inventive concept.

Cosi, ad esempio, nelle figg. da 6 a 10 è illustrata una seconda forma realizzativa per una attrezzatura 101.del tipo comprendente un primo iniettore 102 ed un secondo iniettore 103 per l'iniezione di materiale termoplastico in corrispondenza di una predisposta pressa 104. Thus, for example, in figs. 6 to 10 illustrate a second embodiment for an equipment 101 of the type comprising a first injector 102 and a second injector 103 for the injection of thermoplastic material in correspondence with a suitable press 104.

L'attrezzatura comprende un giraforme 105 provvisto di un corpo centrale 106, presentante preferibilmente conformazione in pianta quadrata, il quale risulta fulcrato in corrispondenza di un primo asse 107 di un primo albero 108. The equipment comprises a turntable 105 provided with a central body 106, preferably having a square plan conformation, which is pivoted at a first axis 107 of a first shaft 108.

In corrispondenza di ciascun angolo di detto corpo centrale 106 sono girevolmente associate, su secondi assi 110a, 110b, 110c e 10d una prima forma llla, una seconda forma lllb, una terza forma lllc e una quarta forma llld. At each corner of said central body 106 a first shape 11a, a second shape 11a, a third shape 11c and a fourth shape 11ld are rotatably associated on second axes 110a, 110b, 110c and 10d.

In questo caso l'utilizzo dell'attrezzatura prevede, a partire dalla condizione illustrata in fig. 8, il posizionamento della prima forma llla e della seconda forma lllb entro la pressa 104 e iniezione ad esempio di un primo colore in corrispondenza del primo iniettore 102 e di un secondo colore in corrispondenza del secondo iniettore 103. In this case, the use of the equipment foresees, starting from the condition illustrated in fig. 8, the positioning of the first form 11a and the second form 11b within the press 104 and injection, for example, of a first color in correspondence with the first injector 102 and of a second color in correspondence with the second injector 103.

Il procedimento prevede successivamente l'apertura della pressa 104 e una rotazione antioraria di circa 90° della prima forma llla e della terza forma lllc e, contestualmente, una rotazione oraria di circa 90° della seconda forma lllc e della quarta forma llld, come illustrato in fig. 9. The procedure subsequently provides for the opening of the press 104 and an anticlockwise rotation of about 90 ° of the first form 11a and of the third form 11c and, at the same time, a clockwise rotation of about 90 ° of the second form 11c and of the fourth form 11d, as illustrated in fig. 9.

Il procedimento prevede quindi una rotazione di 90° del corpo centrale 106 cosi da posizionare in corrispondenza della pressa 104 la prima forma 111a e la quarta forala 111d per potereffettuare ad esempio una seconda iniezione in corrispondenza della prima forma 111a ed una prima iniezione in corrispondenza della quarta forma 111d. The process therefore provides for a 90 ° rotation of the central body 106 so as to position the first form 111a and the fourth hole 111d in correspondence with the press 104 in order to be able, for example, to carry out a second injection at the first form 111a and a first injection at the fourth form 111d.

La fase successiva prevede, alla apertura della pressa 104, ad esempio una rotazione antioraria di 90° della quarta forma 111d e della seconda forma 111b ed una pari rotazione oraria della prima forma 111a e della terza forma 111c. The subsequent step provides, upon opening the press 104, for example a 90 ° counterclockwise rotation of the fourth form 111d and of the second form 111b and an equal clockwise rotation of the first form 111a and of the third form 111c.

Così facendo ad una ulteriore rotazione oraria di 90° del corpo centrale 106 seguirà il posizionamento in corrispondenza della pressa 104 della quarta forma 111d e della terza forma 111c nel mentre la forma llla e la seconda forma lllb saranno accessibili ad esempio per lo scalzamento del prodotto già iniettato nei due colori o nei due materiali. In this way, a further 90 ° clockwise rotation of the central body 106 will be followed by positioning in correspondence with the press 104 of the fourth shape 111d and of the third shape 111c, while the shape 11a and the second shape 11b will be accessible, for example, for removing the product. already injected in the two colors or in the two materials.

Naturalmente anche in questo caso le rotazioni del corpo centrale attorno al primo asse e delle forme attorno ai rispettivi secondi assi potranno avvenire contestualmente oppure con una successione diversa da quella indicata, pur rimanendo nell'ambito del medesimo concetto inventivo. Naturally also in this case the rotations of the central body around the first axis and of the shapes around the respective second axes may take place simultaneously or with a different sequence from that indicated, while remaining within the scope of the same inventive concept.

Inoltre la conformazione delle forme nonché il numero delle stesse, la conformazione del corpo centrale e la tipologia di colore o materiali utilizzati potranno essere i più pertinenti a seconda delle specifiche esigenze. Furthermore, the shape of the shapes as well as the number of the same, the shape of the central body and the type of color or materials used may be the most pertinent according to specific needs.

Claims

CLAIMS 1) Equipment for injection molding of parts in thermoplastic material comprising two distinct injectors, which is characterized by the fact that it comprises at least one turntable composed of a central body rotating on a first axis to which they are rotatably associated, on second distinct axes, at least three forms, and a process which is characterized in that it comprises at least two steps of injecting a first color or a first type of material into one of said forms and a second color or a second type of material into a another of said shapes interspersed with phases in which a clockwise or counterclockwise rotation is imposed on said at least three shapes and central body, suitable to allow the positioning of the scrolls between said shapes in said press and the extraction of the remaining molds.

2) Equipment as in claim 1 which is characterized by the fact that said first and second injector are arranged side by side and have a converging axis corresponding to a single press having two molds side by side.

3) Equipment according to claim 1 which is characterized in that said giraform comprises a central body, with a polygonal plan, rotating on a first axis of a first shaft.

4) Equipment according to claims 1 and 3 which is characterized in that said central body has an equilateral triangle shape in plan.

5) Equipment according to claims 1 and 3 which is characterized by the fact that said central body has a square shape in plan.

6) Equipment according to claims 1 and 4 which is characterized in that said central body comprises three first appendages, arranged at about 120 ° from each other, having an equilateral triangle shape.

7) Equipment according to claims 1 and 6 which is characterized in that in correspondence with the vertex of each of said three first appendages, a first, a second and a second axis is rotatably associated with a second axis parallel to said first axis. third form.

8) Equipment according to claims 1 and 7 which is characterized by the fact that a rotation of about 120 ° in a clockwise or counterclockwise direction is selectively imparted to said first, second and third shapes.

9) Equipment according to claims 1 and 3 which is characterized by the fact that a sequence of rotations of about 120 ° each can be selectively imparted to said unit.

10) Process as in claim 1 which is characterized in that it comprises a cycle which, when fully operational, allows to carry out an injection phase of a first color or of a first type of material in said first form and of a second color or of a second type of material in said second form.

11) Process according to claims 1 and 10 which is characterized in that it comprises an opening phase of said press followed by a phase in which a counterclockwise rotation of about 120 ° is imposed on said first form and a clockwise rotation of about 120 To said third form followed by a phase in which said central body is rotated by about 120 °.

12) Process according to claims 1 and 11 which is characterized in that it comprises a closing phase of said press followed by a phase of injection of a second color or of a second type of material in said first form and of a first color or a first material in said third form and the extraction of the injected product from said second form.

13) Process according to claims 1 and 12 which is characterized in that it allows to carry out an opening phase of said press followed by a phase in which a counterclockwise rotation of about 120 ° is imposed on said third shape and clockwise rotation of about 120 ° to said second shape followed by a rotation of about 120 ° of said central body for the repositioning of said third and second shapes on said press and extraction of the injected product from said first shape.

14) Process according to claims 1 and 13 which is characterized in that it comprises a closing phase of said press followed by a phase of injection of a second color or of a second type of material in said third form and of a first color or a first type of material in said second form and the extraction of the injected product from said first form.

15) Process according to claims 1 and 14 which is characterized in that it comprises an opening phase of said press followed by a phase in which a counterclockwise rotation of about 120 ° is imposed on said second form and a clockwise rotation of about 120 ° to said first form and, at the closure of the cycle, the rotation of said central body by about 120 ° with subsequent closure of said press.

16) Equipment according to claims 1 and 5 which is characterized in that at the corners of said central body a first, second, third and fourth shape are rotatably associated on second axes parallel to said first axis.

17) Equipment according to claims 1 and 16 which is characterized by the fact that a rotation of about 90 ° in a clockwise or anticlockwise direction is selectively imparted to said first, second, third and fourth shapes.

18) Equipment according to claims 1 and 17 which is characterized by the fact that a sequence of rotations of about 90 ° each can be selectively imparted to said central body.

19) Process according to claims 1 and 10 which is characterized in that it comprises an opening phase of said press followed by a phase in which an anticlockwise rotation of about 90 ° is imposed on said first and third shapes and a clockwise rotation of about 90 ° to said second and fourth shapes followed by a phase in which said central body is rotated by about 90 °.

20) Process according to claims 1 and 19 which is characterized in that it comprises a closing phase of said press followed by a phase of injection of a second color or of a second type of material in said first form and of a first color or of a first material in said fourth form and the extraction from said second and third forms of the injected products.

21) Process as in claims 1 and 20 which is characterized in that it comprises an opening phase of said press followed by a phase in which an anticlockwise rotation of 90 ° is imposed on said fourth and second forms and a clockwise rotation of approximately 90 ° to said first and third shapes followed by a rotation of about 90 ° of said central body for repositioning on said press of said fourth and third shapes.

22) Process according to claims 1 and 21 which is characterized in that it comprises a closing phase of said press followed by a phase of injection of a second color or of a second type of material in said fourth form and of a first color or a first type of material in said third form and the extraction from said first and second forms of the injected product.

23) Process according to claims 1 and 22 which is characterized in that it provides for an opening phase of said press followed by a phase in which an anticlockwise rotation of about 90 ° is imposed on said third and first forms and a clockwise rotation of about 90 ° to said fourth and second shapes followed by a rotation of said central body of about 90 ° with closing of said press.

24) Process as in claims 1 and 23 which is characterized in that it provides for an injection step of a second color or of a second type of material in said third form and of a first color or of a first type of material in said second form and the possible extraction from said first and fourth forms of the injected product.

25) Process according to claims 1 and 24 which is characterized in that it comprises a phase of opening said press followed by a phase in which anticlockwise rotation of about 90 ° is imposed on said first and fourth shapes and a clockwise rotation of about 90 ° to said second and first shapes followed by a rotation of about 90 ° of said central body for positioning on said press of said first and second shapes and the possible extraction from said third and fourth shapes of the injected product to close the cycle .

26) Process and equipment as per one or more of the preceding claims which is characterized by what is described and illustrated in the attached drawings.