WO2005102642A1

WO2005102642A1 - Method and equipment for transferring melted polymeric material bodies to the cavities of dies of a moulding machine

Info

Publication number: WO2005102642A1
Application number: PCT/IB2005/000968
Authority: WO
Inventors: Fiorenzo Parrinello; Maurizio Borgatti; Alessandro Balboni
Original assignee: Sacmi Cooperativa Meccanici Imola Societa' Cooperativa
Priority date: 2004-04-23
Filing date: 2005-04-13
Publication date: 2005-11-03
Also published as: MX2007012845A; WO2005102640A3; WO2005102640A2; ITRE20040040A1; WO2005102643A1

Abstract

The invention comprises a plurality of transfer chambers (50) carried by a rotating transfer machine (40) each chamber (50) adapted for containing a polymeric body (D) and having a lower outlet for discharging the polymeric body (D) and being adapted fr influencing the shape of the polymeric body (D) according to the shape of the die cavity. Moreover, the transfer chambers (50) are moved, along a path (P2) wherein each transfer chamber is positioned above the cavity of a bottom die (21) for carrying out the release of the polymeric body (D). The shape of the polymeric body (D) is influenced in the transfer chamber (50), meaning that it shape is reshaped and maintained while it moves from the transfer chamber to the die cavity. An important function of this conditioning of the polymeric body (D) is to make it geometrically suitable for going down into the die cavity without considerable contact with the side zones of the cavity itself.

Description

METHOD AND EQUIPMENT FOR TRANSFERRING MELTED POLYMERIC MATERIAL BODIES TO THE CAVITIES OF DIES OF A MOULDING MACHINE

TECHNICAL FIELD

The present invention relates to a method and equipment for transferring polymeric material bodies, at the melted state, dispensed by at least one dispensing outlet of a polymeric material, to the cavities of the dies of a moulding machine having a plurality of dies moved along an operating path, in particular rotating with continuous motion, in the compression forming of items of polymeric material. The item forming is obtained by relative motion with press-insertion of a punch (male die element) into a hollow bottom die (female die portion) charged with a body (or multiple bodies) of polymeric material at the melted state (where this term means a more or less viscous liquid-pasty state) , in particular a thermoplastic resin, of dosed mass equal to the mass of the item to be formed.

An advantageous application of the invention is for forming pre-forms intended for the subsequent manufacture (typically, by stretch-blowing forming) of plastic bottles. However, the applications could be several and varied.

If the item is said pre-form, for manufacturing bottles and the like, this usually comprises an upper neck provided with projections and a substantially smooth, axially elongated hollow body located at the bottom of the neck.

Typically, the conventional moulding machines of the continuous type for manufacturing items of polymeric material by compression forming are provided with a turntable that carries a plurality of bottom dies and an overlying corresponding plurality of punches. The turntable rotates about a vertical axis and each bottom die, along a complete turn receives a plastic (or other polymeric) body in dosed quantity (dose) heated at the necessary temperature for the plastic to be sufficiently fluid, undergoes a dose pressing step with the reciprocal approach (up to the closing of the die) of the punch and of the bottom die, followed optionally after an item cooling step - by the opening of the die and the extraction of the pre-form from the machine.

The moulding machine is associated to an extruder means that issues polymeric material at the melted state. This material is then divided according to bodies in dosed quantity (doses) that are then transferred into the machine bottom die cavities.

BACKGROUND ART

If the dosed body (dose) of polymeric material has a relatively small mass, it is known to transfer it to the bottom dies of the rotating machine through a transfer device having suitable handling members (so-called "hands") that move in a succession along a circular path and that, along such path, collect the dose from a fixed dispensing outlet, belonging to the extruder of the polymeric material, and release it in the point where the path is tangent and superimposed to the bottom die path. This release must necessarily occur in a very quick manner when the position of the handling member and of the die cavity (that is, the bottom die cavity) is perfectly superimposed and coaxial. This is virtually possible only for relatively small mass doses, for example doses adapted for forming capsule shaped stoppers for closing usual plastic bottles for mineral water or other fizzy drinks.

On the other hand, the technology described is not adapted for loading bodies of polymeric material into the bottom dies when items with a relatively large mass are to be formed, such as the PET (polyethyleneterephthalate) pre-forms currently used on the market for manufacturing (by the known stretch- blowing operation) the usual plastic bottles. In this case, in fact, virtually it is not possible to transfer the doses from the handling members inside the die cavities, with an almost instant action, since the doses exhibit a relatively high length and a sufficiently long time is therefore needed to carry out such transfer, which is not possible with the conventional transfer devices described.

In order to solve this technical problem, a moulding machine has been proposed (patent application WO 03/047834) wherein the doses are released by a dispensing device having a plurality of dispensing outlets moving in a succession along a circular and horizontal path; at the same time, the bottom dies do not move along a circular path, rather, they have a fair possibility of moving in radial- direction relative to the turntable, and thus they can follow by a certain arc the circular path of the dose dispensing outlets, diverting relative to the conventional circular path. Thus, for a certain portion of the path (and thereby for a certain time) , the dispensing outlet is placed coaxial and on the bottom die cavity and its motion coincides with the motion of the latter.

However, one disadvantage of such solution is the complexity and the construction cost of such moulding machine, considering that such machine is very complex, both for the usually very high number of bottom dies required, and for the several operations that are carried out, and for the relatively high speed it is required to operate, and finally for the fact that bottom dies require a very accurate positioning, whereas on the other hand, making them movable relative to the turntable complicates this requirement as a consequence. Moreover, in the proposed solution, based on the radial movement of the bottom dies, into said common portion, it is not even possible to obtain a correct equality of the bottom die motion and of the dispensing outlets, as it would be needed; in fact, the peripheral bottom die speed necessarily varies as its radial position varies, whereas the same does not happen for the dispensing outlets whose radial position is constant; as a consequence, in said common portion the dispensing outlets cannot remain coaxial with the underlying die cavities and therefore, the dose transfer cannot be correct; if the dose diameter is close to the cavity diameter, it is not even possible to make the transfer. The technical problems related to the dose transfer to the bottom die cavities are further increased by the fact that the means for carrying out the dose transfer operations, of various shape and type, unavoidably exhibit surfaces that come into contact with such polymeric bodies at the melted state. In fact, the polymeric material tends to adhere to the surfaces of the means with which it comes into contact, due to its physical state (more or less viscous liquid at a temperature usually higher than 200 °C, when it is PET) . Such adhesive effect considerably hinders the movement of the polymeric body, creating serious problems, especially if the polymeric body moves by simple gravity. For example, if the polymeric body must slide by gravity along a surface accompanying it, its tendency to adhere to such surface can affect the motion so as to make the scheduled operation impossible.

Or, if the polymeric body is left to drop within the die cavity, especially where it has a relatively narrow and deep shape, if it comes into contact with the cavity walls, it unavoidably tends to adhere thereto and does not arrange properly inside the cavity. If, for example, the polymeric body has a relatively large volume compared to the cavity volume, there exists the serious problem that the body itself could protrude on top out of the cavity by such an extent as to make the closing of the bottom die impossible in the compression step by the punch.

Moreover, said adherence problems are strongly increased by the fact that the polymeric body drop occurs while the bottom die moves continuously along a circular path, and also at a relatively high speed, since due to the centrifugal effect it is subject to, the polymeric body is pushed towards the side wall of the cavity. It should be added that in the contact of the polymeric body with foreign bodies, an effective heat transmission occurs, localised in the contact zone, that consequently alters the regular and substantially even distribution of the thermal values of the polymeric body; in particular, excessive even though localised drops in temperature can occur, such as to create micro- crystallisation or micro-solidification of the material, or in any case seeds of irregularities in the material that could later produce unevenness and problems in the end product. Finally, it should be added that while in the transfer of doses with relatively small mass, this normally exhibits the shape of a more or less regular ball and can undergo rotations or rolling in the transfer of polymeric bodies with relatively high mass and relatively complex shape (for example, for forming PET pre-forms), it is normally necessary to introduce such bodies in the die cavity with the axes (or at least one axis) arranged according to a given orientation. A technology capable of achieving this is therefore needed.

DISCOSURE OF INVENTION

An object of the present invention is to provide a method and a relevant equipment capable of overcoming said technical disadvantages.

The invention comprises a plurality of transfer chambers, carried by a rotating transfer machine, each adapted for containing a polymeric body and having a lower outlet for discharging the polymeric body itself, each chamber being adapted for influencing the shape of the polymeric body according to the shape of the die cavity. Moreover, the transfer chambers are moved, along a path wherein each transfer chamber is above the cavity of a bottom die for carrying out the release of the polymeric body to the bottom die cavity.

According to the invention, therefore, the dose shape is influenced in the transfer chamber, meaning that its shape is reshaped, that is, a shape is imparted to it that (usually) differs from the shape it exhibits when it arrives at the transfer chamber. The polymeric body takes the desired reshaped shape while it is completely inside the transfer chamber, and keeps it while it moves from the transfer chamber to the die cavity. According to an embodiment, the polymeric body shape is influenced by the shape of the inside cavity of the transfer chamber, especially by the shape of the side surface. The extent at which the polymeric body tends to have the shape of the inside cavity of the transfer chamber depends on the material viscosity (which in turn is function of the intrinsic polymer characteristics, type and molecular weight) , on the temperature and on the residence time.

According to a different embodiment, the polymeric body shape is shaped ^'using a fluid introduced into the transfer chamber.

An important function of this conditioning of the polymeric body is to make it geometrically suitable for going down into the die cavity without considerable contact with the side zones of the cavity itself. The shape given to the polymeric body inside the transfer chamber is such that it allows it to penetrate into the cavity without coming into contact with the side walls thereof during the descent, or in any case if a contact occurs, this is not such as to hinder its descent and its correct position into the cavity itself. This is very useful especially if the die cavity is relatively deep and narrow relative to the dose mass and/or the operating speeds are relatively high. Another important function of this conditioning of the polymeric body is to make its shape such as to be functional to an optimum pressing, meaning to obtain an item exhibiting the best physical-chemical characteristics . For example, it has been found that a shape of the polymeric body as to make it as much as possible conforming to the die cavity wherein it is introduced gives the best results in terms of the item obtained; if, on the other hand, a polymeric body exhibits a shape quite different from that of the cavity where it is introduced, in the compression forming it undergoes harmful major localised deformations and a lower physical-chemical quality item is obtained. According to an important aspect of the invention, means for completely or partly reducing the adhesion between the polymeric body and the contact surface of the transfer chamber is provided. In particular, such means feeds fluid inside the chamber itself for forming a fluid interspace between the contact surface of the chamber itself and the polymeric body. It also makes the passage of the polymeric body from the transfer chamber to the die cavity quick and regular. Other factors that favour this passage are the presence of fluid under pressure into the transfer chamber, which when the lower outlet of the chamber opens quickly shoot the polymeric body downwards.

In particular, there is provided closing means, adapted for closing the upper base of the transfer chambers and means adapted for providing fluid under pressure through such closing means, for delivering the fluid into the chamber in order to push, under pressure, the polymeric body out through the lower outlet.

In general, thanks to the invention, the passage of the polymeric body from the transfer chamber to the bottom die cavity can be obtained in a very quick and regular manner, and at the same time the contact between the means handling the body and the body itself is avoided, or is at least made irrelevant, thus overcoming the disadvantages described above. In general, it is possible to obtain a more accurate positioning of the viscous polymeric body, with great advantages in the compression forming technology for all applications. This also applies if the bottom die cavity is relatively deep and narrow relative to the dose mass and/or the operating speeds are relatively high. Moreover, the axial distance between punches and bottom dies that must be provided in the zone wherein the polymeric bodies are introduced into the bottom dies is relatively small, it substantially being equal to the length of a body itself, with certain advantage for the speed of the forming cycle. The invention will be described in detail hereinafter with reference to the accompanying figures, which show some exemplifying and non-limiting embodiments of the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a schematic plan view of a first embodiment of the equipment for transferring (dosed) bodies of polymeric material dispensed by a fixed dispensing outlet of polymeric material, to a plurality of bottom dies carried by a moulding machine with turntable rotating with continuous motion, according to the invention. FIG. 2 is an enlarged detail of Fig. 1. Fig. 2A schematically shows the kinematic aspects of Fig. 2

FIGS. 3A - 3F show a schematic vertical section view of a sequence of steps carried out by the equipment of Fig. 2 in the transfer of the polymeric bodies from the dispensing outlet 11 to the bottom die cavities.

Fig. 4 schematically shows an axial section, vertical elevation view of a particular embodiment of the transfer chamber of the equipment of Fig. 2. Fig. 4A is the section according to plane A- A of Fig. 4.

Fig. 5 schematically shows an axial section, vertical elevation view of a modified embodiment as compared to Fig. 4. Fig. 6 shows a schematic, axial section, vertical elevation view of a further embodiment of the transfer chamber of the equipment of Fig. 4.

Fig. 7 shows a schematic, axial section, vertical elevation view of a further modified embodiment as compared to Fig. 4. Fig. 8 shows a section according to a cross plane, according to a different embodiment of the transfer chamber 50.

Fig. 9 is a perspective view of an embodiment of the handling means 31 for transferring single polymeric bodies from the dispensing outlet to the transfer chamber, in the equipment of Fig. 2.

Fig. 10 is a view like Fig. 2A, where the same first transfer machine 40 is associated to a second machine 30, for transferring the polymeric bodies to the transfer chambers, obtained according to a different embodiment as compared to that of Fig. 2A. Fig. 11 is the section according to a generic axial and vertical plane of the second transfer machine 30.

DETAILED DESCRIPTION OF THE INVENTION

The equipment according to the invention comprises a plurality of transfer chambers 50, carried by a rotating transfer machine, each adapted for containing a polymeric body and having a lower outlet for discharging the polymeric body itself, where each chamber is adapted for influencing the shape of the polymeric body according to the shape of the die cavity. According to the invention, each transfer chamber 50 is moved along a path wherein it is above the cavity of a bottom die for carrying out the release of the polymeric body into the underlying cavity.

Figures from 1 to 3F show an embodiment of an equipment for transferring dosed bodies D of polymeric material, coming out of a fixed dispensing outlet 11 of polymeric material, belonging to an extruder means 10, to a plurality of bottom dies 21 carried by a moulding machine 20 with turntable rotating with continuous motion. The extruder means 10 is of the known type and is only schematically shown in the figures. As known, the extruder means 10 heats the polymeric material at a suitable temperature (for example, about 270°÷300°C for PETs) so as to bring it to the more or less viscous melted state, so that it can take a sufficient mobility and dispense it from a fixed dispensing outlet 11.

The dispensing outlet 11 dispenses a continuous extruded cord M (typically with circular section) of fluid polymeric material which is divided in a regular manner, creating a succession of dosed bodies D of polymeric material; for example, a knife 13 (or multiple knives) are provided, operating adjacent to outlet 11, which cuts the extruded M, exactly dividing it according to a succession of bodies D of dosed mass (Fig. 3A) . The bottom dies of the forming dies (globally indicated with reference numeral 21) are brought into rotation, along a circular path that develops in a horizontal plane, by a turntable 26 with vertical axis, belonging to a conventional moulding machine 20 operating with continuous movement, which comprises a corresponding plurality of upper punches 27, also carried by turntable 26, adapted for penetrating into the cavities of the corresponding bottom dies 21 for forming, under compression, the desired items of polymeric material (for example the pre-forms) . The bottom die illustrated in figures 3E and 3F is intended for forming pre-forms adapted for manufacturing afterwards (typically, by blowing forming) bottles of thermoplastic resin (in particular, PET) ; such pre-forms comprise a neck, having the final shape provided for the bottle, and a hollow body, intended, in the bottle manufacturing step, for forming the container body of the same. In this case, the bottom die consists of a concave lower bottom die portion 21a and of an upper bottom die portion 21b with thorough cavity. The lower portion 21a exhibits a cavity whose surface is concave and smooth, substantially cylindrical, which imparts the shape to the outer surface of the hollow pre-form body, whereas the upper portion 21b exhibits a thorough cavity whose surface is concave which imparts the shape to the outer surface of the neck. Since this is provided with radial projections, said upper portion 21b is divided into at least two half-portions (in the illustrated case they are two) adapted for being transversally moved away from one another for releasing the pre-form. Said concave surfaces of the two portions 21a and 21b form the cavity of bottom die 21, which defines the so-called die cavity.

Of course, the invention can be used for the introduction of the polymeric body D into bottom dies 21 wherein the cavity is shaped differently, or consists of the lower portion 21a only, without the upper portion 21b. Moreover, bottom die 21 can be suitable for forming products other than pre-forms. Each bottom die 21 is brought into rotation by turntable 26 along with the other bottom dies 21.

At the extraction zone of the items formed by the moulding machine 20, a machine 60 is located for drawing out and moving away such items from machine 20. According to the embodiment of the invention illustrated in figures from 1 to 3F, for transferring the polymeric bodies D coming from the fixed dispensing outlet 11 to the cavities of bottom dies 21, there is provided a first transfer machine 40, rotating about a vertical axis, which moves a plurality of transfer chambers 50 brought into continuous rotation, each adapted for containing a polymeric body D and for afterwards transferring it to the cavity of a bottom die 21, though the lower outlet thereof. This transfer machine 40 comprises moving means adapted for moving in a succession the transfer chambers 50 along a path wherein each transfer chamber 50 moves above the cavity of a bottom die 21 for carrying out the release of the polymeric body D to the cavity itself. According to the particular embodiment shown, by way of an example, in figures 2 and 2A, machine 40 moves the transfer chambers 50 along a same path P2 that has a portion Tl concomitant with path P3 of dies 21, along which each transfer chamber 50 is in coaxial position and above the cavity of a bottom die 21 and its motion coincides with the motion of the latter; and just along this portion Tl the polymeric body D is transferred to the cavity of bottom die 21.

This moving means comprises a rotating circular support 46, arranged on a horizontal plane, rotating in synchronism with the moulding machine, about a fixed axis vertical shaft 47. Said moving means further comprises a plurality of mechanisms 41, each carrying a respective transfer chamber 50 at its free end; each of said mechanisms 41 is provided with two degrees of freedom relative to support 46 and also comprises constraining means adapted for determining its motion in relation to the angular position of the rotating support 46. According to the particular embodiment illustrated in figures 2 and 2A, each mechanism 41 consists of an articulated arm having two members pivoted to one another, of which a first member 41a is pivoted with its inner end to the rotating support 46, and with the other end to the second member 41b; the latter has a free end the carries said transfer chamber 50.

Said constraining means comprises, for the series of members 41a of mechanisms 41, a relative fixed track 45A acting on driven means (idle rollers 45' ) carried by members 41a themselves; and respectively, a fixed track 45B, for the series of members 41b, acting on driven means (idle rollers 45' ) carried by members 41b themselves. This is to univocally define the movement of the transfer chamber 50 during each rotation of support 46. These tracks 45A and 45B constrain suitable points of the two members 41a and 41b of mechanism 41 to follow respective paths; for each angular position of each mechanism 41 relative to the fixed portion of the equipment, the position of its members 41a and 41b relative to support 46 remains univocally determined and therefore, the motion of mechanisms 41 and consequently, path P2 of the transfer chambers 50 and their motion along path P2 itself remains univocally determined, in combination with the motion of support 46 itself. It is possible to suitably design the path of tracks 45A and 45B so as to obtain a consequent path P2, along which the transfer chambers 50 are carried in a succession (figure 2A) , having a portion Tl that is concomitant with the circular path P3 of the bottom dies, and along this portion, each transfer chamber 50 is in coaxial position and above the cavity of a bottom die 21 and its motion coincides with the motion of the latter; the polymeric bodies D are therefore transferred along this portion Tl from chambers 50 to the cavities of bottom dies 21.

By providing a suitable length for portion Tl concomitant with paths P2 and P3, thanks to the coincidence of the movements in such portion Tl, a relatively high time is provided (depending on the rotation speed of the moulding machine 20 and on the length of the concomitance portion Tl) during which it is possible to carry out the transfer of each body D to the cavity of a bottom die, while the transfer chamber 50 remains superimposed and exactly coaxial therewith. Also other mechanisms 41 could be used, differing from those illustrated above but equivalent to them as regards the operation and the kinematic effects required herein. In the embodiments illustrated in figures 2 and 2A, path P3 of bottom dies 21 is circular and as a consequence, the concomitant portion Tl is shaped as a circumference arc. However, path P3 can be made with a different shape; for example, it can exhibit a rectilinear portion, along which also portion Tl is determined. In this case, the centrifugal thrust on the polymeric body advantageously is null or almost null.

For the use of the invention, different moving means could be adopted, such as to cover paths other than those illustrated above, for example wherein the transfer chambers are superimposed to the bottom die cavities in one point only.

According to the invention, there is provided means adapted for transferring the polymeric bodies D from the dispensing outlet 11 to the transfer chambers 50. This means can consist of a second rotating transfer machine 30, adapted for moving the polymeric bodies away from the fixed point from where they come out (the dispensing outlet 11) and transferring them, with a motion having horizontal component, to the transfer chambers 50 (as in the embodiments illustrated in figures described hereinafter) .

According to the embodiment illustrated in figures 2, 2A from 1 to 3F, 9, said second rotating transfer machine 30 comprises a plurality of handling means 31, carried in continuous rotation. Each means 31 exhibits a concave inner surface 32b, with "U" cross section open on a side, intended to come into contact with the polymeric bodies D. Surface 32b has an axial development according to a substantially vertical axis and such shape as to define a channel open on one side capable of accompanying the polymeric bodies D making them slide in contact with it.

The second transfer machine 30 exhibits moving means adapted for actuating in a succession the handling means 31 so that it transfers, with a relative movement in cross direction, polymeric bodies D of polymeric material at the melted state coming out of the dispensing outlet 11 and arranges them one at a time into the transfer chambers 50. Said moving means comprises a circular support 36, arranged on a horizontal plane, rotating in synchronism with the moulding machine, about a vertical shaft coaxial with shaft 47 of support 46 (or about a shaft away from shaft 47) having fixed axis, at the periphery of which there is fixed the handling means 31, arranged with the open side of surface 32b facing tangentially forward relative to the direction of rotation. The path P4 covered by the contact surfaces 32b (Fig. 2A) develops on a horizontal plane and is arranged below and at a short distance from the dispensing outlet 11 (but sufficient to avoid the collision against the lower end of extrusion M that comes down from the outlet itself) , so that the upper end of the contact surface 32b moves below outlet 11, knife 13 being interposed; moreover, said path P4 is arranged above and at a short distance from the underlying path P2 of chambers 50, so that the lower end of the contact surface 32b moves slightly touching the upper end of chambers 50. The path P4 covered by means 31 is circular an a portion thereof (indicated with T2) is made concomitant with path P2 of transfer chambers 50. During this portion T2, each handling means 31 is in coaxial position and above a transfer chamber 50 and its motion coincides with the motion of the latter. Since the path P4 covered by means 31 is rigidly circular, it being rigidly fixed to support 36, path P2 of the transfer chambers 50 is the one that, by suitably shaping the path of the fixed tracks 45, is made to deviate relative to a circular path and made to coincide with said portion T2 of path P4 of the handling means 31. The dispensing outlet 11 is located in the proximity of the upstream end of said portion T2.

In use, means 31 is made to pass below the dispensing outlet 11, where body D, just cut by knife 13, enters into the concavity formed by the contact surface 32b and is pushed by contact in horizontal motion by the latter. In the meantime, body D also moves by gravity downwards, sliding in a guided manner along the contact surface 32b itself, until it leaves it and falls within an underlying transfer chamber 50. This transfer is carried out along portion T2, along which, as said before, the contact surface 32b is arranged above and coaxial with a transfer chamber 50 and moves with it with the same motion. Thanks to the concomitant portion T2 of paths P2 and P4 that will have suitable length and to the coincidence of the movements in such portion T2, a relatively high time is provided (depending on the rotation speed of the moulding machine 20 and on the length of portion T2) during which it is possible to carry out the proper transfer of each body D from the dispensing outlet 11 to the transfer chamber 50.

The lower portion 33 of surface 32b is closed and converging (like a funnel) in order to improve the descent of item D into the release seat. Figures from 3A to 3D show the crucial steps of the transfer of the polymeric body D from the dispensing outlet 11 to the transfer chambers 50 by the handling means 31, all of which occur into said concomitant portion T2. Fig. 3A shows body D just entered into the concavity of surface 32b and just separated from the extruded element M by the action of knife 13. This step corresponds to position Ql of Fig. 2A.

In figures from 3B to 3D, the polymeric body D goes down accompanied by surface 32b until it fully enters into the underlying transfer chamber 50 (Fig. 3D) . Figures 3E, 3F show the crucial steps of the transfer of the polymeric body D from the transfer chamber 50 to the underlying cavity of a bottom die 21, all of which occur into said concomitant portion Tl.

According to the embodiment illustrated in figures 10 and 11, the second transfer machine 30 for transferring the polymeric bodies D from the dispensing outlet 11 to said transfer chambers 50 comprises a turntable 15, associated to said fixed dispensing outlet 11, carrying in its periphery a plurality of secondary dispensing outlets 16 adapted for dispensing polymeric material at the melted state, which are moved along a circular path P'4 laying on a horizontal plane. More in detail, turntable 15 rotates about a vertical central axis 15A and exhibits an upper outlet 152, located on axis 15A, which is connected by a rotating connecting joint 151 to the fixed outlet 11; joint 151 ensures the continuity of the fluid connection between the fixed outlet 11 and the rotating outlet 152.

Inside turntable 15 there are obtained a central channel 153 that branches off from outlet 152 and develops along axis 15A, and a plurality of cross channels 154 all of which branch off radially, from the lower end of the central channel 153 and feed as many secondary outlets 16, facing downwards with vertical axis, distributed on the periphery of turntable 15 and arranged at the same distance from axis 15A and angularly arranged at the same distance from one another. Each outlet 16 is adapted for dispensing an extrusion of polymeric material and each of them is associated to a means for dividing such extrusion into a plurality of polymeric bodies D. For example, said means for dividing is a gate means 17 axially mobile into the outlet and adapted for closing openings 161 of outlets 16, thus dividing the polymeric extrusion. Alternatively, the means for dividing may be a knife (not shown) . The described turntable 15 with relevant associated members is already known; for example, it is of the type described in patent application PCT/EP2003/07325 filed by the same applicant.

The handling means of the transfer chambers 50 is adapted for moving in a succession such chambers 50 so that their path P2 has a portion concomitant with path P'4 of the secondary dispensing outlets 16 (this portion is indicated with T'2 in Fig. 10), during which each transfer chamber 50 is in coaxial position and below a secondary outlet 16 and its motion coincides with the motion of the latter, the transfer of the polymeric body D being carried out in this portion to the transfer chamber 50.

In use, the extruded element of polymeric material continuously moves downwards from the dispensing outlet 11 and, through channels 153 and 154, it reaches the secondary outlets 16. These work in synchronism with the movement of turntable 15 dispensing, one at a time in a succession (or also multiple outlets at the same time) , a polymeric body D, while they cover said portion T'2 wherein they are precisely superimposed to chambers 50 and, during said portion body D falls by gravity within the underlying transfer chamber 50.

Thanks to the concomitant portion T2 of paths P2 and P'4 that will have suitable length and to the coincidence of the movements in such portion T'2, a relatively high time is provided (depending on the rotation speed of the moulding machine 20 and on the length of portion T'2) during which it is possible to carry out the transfer of bodies D from each secondary dispensing outlet 16 to the underlying transfer chamber 50. As an alternative to the second transfer machine 30 described above, means can be provided, adapted for carrying out said transfer only by vertical descent of the polymeric body from the fixed dispensing outlet 11 directly to the transfer chamber 50; in this case, there is provided dose transferring means having members associated to the outlet itself (a piston that pushes and cuts the extruded material, one or more knives that cut the extruded material, etc.), which make the polymeric body detach from the dispensing means, and thereby fall by gravity (or for other factors, for example a compressed air push, etc.) into the transfer chamber, this being arranged below the outlet itself. According to the invention, transfer chambers 50 comprise means adapted for geometrically influencing the shape (and of course, the relevant size) of the polymeric body D.

In the first place, this conditioning is to make the polymeric body D suitable for going down in the cavity of bottom die 21, without coming into contact with its wall during the descent, or in any case with such contact as not to hinder the descent, and therefore to properly introduce it into the bottom die cavity. While it is completely inside the transfer chamber, the polymeric body D takes the desired reshaped shape and keeps it while it moves from the transfer chamber to the die cavity.

This aspect of the invention is advantageous especially (not only) if the bottom die cavity is relatively deep and narrow relative to the mass of the polymeric body D and/or the operating speeds are relatively high. A typical case is in the forming of PET pre-forms, used for manufacturing the usual plastic bottles for mineral water or other fizzy drinks, in this case the bottom die cavity being relatively deep and narrow as compared to the dose mass.

Thanks to this aspect, as already mentioned above, the passage of the polymeric body from the transfer chamber to the bottom die cavity can be carried out in such quick manner that said concomitant portion Tl of paths P2 and P3, during which each transfer chamber 50 is in coaxial position and above the cavity of a bottom die 21, can be unnecessary.

According to a preferred embodiment, it is the same shape of the inner cavity 50a of the transfer chamber 50 the one that geometrically influences the shape of the polymeric body D. That is, body D is introduced in the transfer chamber 50 with a shape that can be different from that of the inner cavity 50a of the chamber itself, and it is physically influenced thereby meaning that it comes into contact with it and takes the same shape as it, especially the shape of the side surface, thanks to its intrinsic fluidity and plasticity.

In this meaning, according to the embodiment illustrated in figures 3A - 3F, 4, 6, 7 the inner cavity 50a of the transfer chamber 50 is laterally delimited by the inner surface 51b of a side wall 51, which surface is cylindrical, with section of a shape corresponding to the shape of the section of the bottom die cavity, with vertical generatrices, and its cross size is smaller than the minimum cross size on the inlet zone of the bottom die cavity. In the frequent case where the generic cross section of the bottom die is circular, also the inner surface 51b exhibits circular section. In the case illustrated, for example, in figures 3E and 3F, the cavity of the upper portion 21b of the bottom die has a smaller diameter than the side cylindrical surface of the lower portion 21a. In this case, the diameter of the inner cavity 50a is a little smaller than the diameter of the cavity of the upper portion 21b.

The contrary applies if the side cylindrical surface of the cavity of the lower portion 21a of the bottom die has a smaller diameter than the cavity of the upper portion 21b. When body D is released from chamber 50 into the cavity of the underlying bottom die 21, it already has such shape that enables it to penetrate into the cavity without or hardly coming into contact, during the descent, with its side walls, or in any case if a contact occurs, this does not considerably hinder the descent and its proper positioning inside bottom die 21. The transfer chamber 50 comprises connectable and disconnectable means adapted for preventing the descent of the polymeric body and alternately adapted for releasing the body itself.

In particular, as shown in figures 4 - 6, the inner cavity 50a of the transfer chamber 50, besides being laterally delimited by the cylindrical and closed side wall 51, is delimited at the bottom by^' a lower base wall 52 adapted for taking (by means not shown) a closing position and alternately an opening position of the lower outlet.

In the step in which the transfer chamber 50 receives the polymeric body D from the dispensing outlet 11, the lower wall 52 is in closed position; on the other hand, in the step in which the transfer chamber 50 releases the polymeric body D to the bottom die cavity, the same lower wall 52 is in open position. According to the embodiment shown in the figures, the lower base wall 52 is flat and, to move to the open position, it moves remaining in the same horizontal plane as it is when in closed position, with sliding adhering to the lower end edge of the side wall 51; in particular, it moves under rotation, relative to the side wall 51, about the vertical axis pin 521 constrained to wall 51.

Also other portions of chamber 50, besides the side wall 51, can serve to influence by contact the shape of the polymeric body D. In particular, the inner surface 52b of the lower wall 52, which comes into contact with the lower end of body D, can be shaped so as to model such end of suitable shape. For example, it can be a more or less pointed and rounded shape that allows the polymeric body a better introduction along the bottom die cavity, especially when the latter is relatively long and narrow. Or it can be a shape similar to that of the lower end of the bottom die cavity. Also in this case, the lower base wall can be porous to enable the passage of the anti-adhesion fluid through its thickness and moreover it consists of at least two portions that can be opened with a more ox less centrifugal movement. Since the polymeric body D comes into contact with the inner surface of cavity 50a of the transfer chamber 50, especially with the side inner surface 51b and with the inner surface 52b of the lower wall 52, chamber 50 comprises means for partly or totally reducing the adhesion caused by such contact.

According to an embodiment of the transfer chamber 50, illustrated in Fig. 4, this means is adapted for providing a fluid, in particular a gas (preferably air) in the cavity of chamber 50 itself. In particular, this means emits gas for forming a gas interspace between the inner surface of the transfer chamber 50 and the polymeric body D such as to decrease the adhesion effect between the polymeric body D itself and the inner contact surface.

Preferably, the side wall 51 and the lower base wall 52 of the transfer chamber are porous so as to allow the gas passage through their thickness. In this case, an embodiment provides for a second outer side wall 51' coaxial to the side wall 51, which surrounds it and is connected thereto at the upper and lower edge. A side chamber 51a is defined between the two walls 51 and 51' which surrounds the side porous wall 51 by 360 degrees and extends by the entire or nearly the entire height thereof, which is connected to means (not shown in the figures) adapted for delivering gas under pressure, through a channelling 59 and inlets 56, inside chamber 51a itself and hence through the porous wall 51 inside the transfer chamber 50.

Moreover, if a lower base wall 52 is provided, a second outer base wall 52' is provided, located at the bottom of wall 52 and connected thereto through the outer edge. A thin lower chamber 52a is defined between the two walls 52 and 52' extends by the entire extension of the base wall 52, which is also connected to said means adapted for delivering gas under pressure inside chamber 52a itself and hence through the porous wall 51, inside the transfer chamber 50. The gas under pressure is delivered to chambers 52a and 51a, and hence it passes through the porous walls 52 and 51 forming a gas interspace arranged between the inner surfaces 52b and 51b of walls 52 and 51 and the outer surface of the polymeric body D. This gas interspace has the effect of avoiding the contact between the polymeric body D and walls 52 and 51 or at least reduce the time and the extension of the contact zones, thus reducing the macroscopic adhesion effect between the polymeric body D and walls 52, 51, favouring an effective downward sliding of the body itself. It has been found that, by interposing a fluid interspace with sufficient pressure and flow rate values (that vary according to the application, and are in any case relatively easily assessable) between the contact surface and the polymeric body D, it is possible to totally or at least partly reduce the effect of adhesion of the polymeric body D so that, in the practice, this does not stick and does not adhere to the surface. In fact, forming a fluid interspace with appropriate pressure and flow rate values, which are generally relatively low (one or few bar are sufficient) , the contact between the polymeric body D and the contact surface is avoided. If the contact occurs anyway, this is localised and limited over time. To this end, it has been experimentally proved that limiting the contact time between the polymeric body D and the surface to relatively low values, a correspondingly macroscopic limited adhesion effect occurs; if the adhesion time is of few micro-seconds, the macroscopic adhesion effect is virtually null.

The phenomenon can be explained with the fact that, to obtain an adhesion effect, the contact time needed is not less than such a value (reaction time) that the chemical-physical adhesion strengths can have effect. This reaction time is function of the material, of the temperature and of the local pressure. The fluid interspace causes the continuous interruption of this process, so that the maximum adhesion does not occur; or it even avoids any contact. Excellent results are obtained by making the above porous walls with a material whose pores have a diameter comprised between 5 x 10^~3 mm and 20 x 10^"3 mm and delivering gas in the chamber at a pressure of 0,5 - 1 bar. In a first embodiment alternative to the use of porous walls, walls of non-porous material can be provided, on which however several small holes are made, such as to allow the fluid passage through them, distributed on the zone where contact with the polymeric body D occurs (Fig. 5) . For example, such holes can have a helical distribution to obtain the maximum coverage on the contact zone.

According to a further alternative embodiment, said porous wall is replaced by a wall obtained with a plurality of elements sided to one another so as to form a plurality of lines of reciprocal separation relatively thin, shaped and distributed in an appropriate manner on the • contact zone, through which the fluid passage is carried out. In a further alternative embodiment, the fluid can be delivered inside the transfer chamber 50 with means that emits a direct flow tangent to the contact surface 52b, 51b so as to develop an interspace that touches the surface itself, avoiding the adhesion of body D to the contact surface.

An example of embodiment is illustrated in Fig. 7, where a transfer chamber 50 is shown, whose side wall 51 is continuous and not porous. This chamber is not provided with lower base wall. To prevent the descent of the polymeric body, an annular duct 71 is provided, located below the lower edge of the side wall 51, that surrounds the lower outlet of chamber 50, but without hindering the output of the polymeric body D. Duct 71 is fed, through one or more inlets 72, with a fluid under pressure that produces fluid jets, coming out through openings 73 suitably oriented upwards, directed upwards, towards the lower outlet of chamber 50. By suitably calibrating the pressure characteristics of the emitted fluid, it is possible to obtain an effect that keeps the polymeric body D suspended, inside chamber 50, preventing it from going down through the lower outlet. Of course, the feeding of the fluid to duct 71 is dispensed when the body D descent has to be blocked and on the other hand, it is interrupted when the descent of body D has to be carried out .

The same fluid can be suitably directed so as to create also a fluid interspace to prevent the adhesion of body D to the contact surfaces. The described advantageous effect produced by the fluid interspace is further increased by thermally influencing the same fluid delivered between the contact surface and the polymeric body D, so as to decrease the temperature of the surface of the polymeric body D and/or of the contact surface.

To this end, means (not shown in the figures) can be provided, adapted for thermally influencing the gas so as to drop its temperature. In this case, the gas interspace formed between the inner surface of the transfer chamber 50 and the outer surface of the polymeric body D also produces an effective heat exchange with the mass of walls 52 and 51 and with the outer surface of the polymeric body D, that can advantageously be used to promote the sliding of the polymeric body D itself. The cooled fluid, passing through the wall, or simply touching both the contact surfaces 51b and 52b and the surface of the polymeric body D, decreases at least in surface their temperature, thus increasing the viscosity of the polymeric body D, thus decreasing the adhesion of the plastic material. In fact, it has been found that if the contact time is increased (from microseconds to milliseconds) , it is necessary to decrease the wall temperature to prevent adhesion. In the case described above where the contact surface is located on a wall made of a porous material, or in the case where the fluid passes through relatively narrow openings, the fluid itself in se has a favourable "cooling effect" due to its expansion in output, in the passage through the wall.

Of course, the fluid temperature is calibrated so as to prevent excessive dropping, even though localised, of the polymeric body D such as to produce micro- crystallisation of the material or in any case, seeds of irregularities in the material. Anyway, the cooling effect on the polymeric body produced by the fluid is totally different from that obtained by relatively long direct physical contact of the body itself with the contact surface of the dose handling means. In fact in the first case, a sort of micro-cooling occurs that only concerns the most superficial layer of the body of polymeric material D and is distributed on the entire surface thereof in a regular and homogeneous manner; moreover, such cooling is of lower intensity and thanks to the heat conduction arising from the remaining body mass, it is quickly balanced. On the other hand, in the case of contact between the polymeric body D and the handling means, a strong and relatively deep cooling occurs, limited to a relatively small body portion, with harmful consequences for the formed item, as mentioned above.

The cooling effect on the polymeric body in order to totally or partly reduce the adhesion between the polymeric body and the inner surface of the transfer chamber 50 can be obtained by cooling of the walls of the chamber itself, carried out with means other than air, for example with fluid circulation inside the wall to be cooled. According to another important aspect of the invention, a forced fluid, in particular air (or other gas) is introduced into the transfer chamber 50 above the polymeric body for generating a thrust directed downwards for making the output of the polymeric body D through the lower outlet quicker. To this end, closing means is provided, adapted for closing the upper base of the transfer chambers 50, wherein one or more openings are obtained through which, by suitable means for dispensing fluid under pressure, forced fluid is dispensed into the chamber 50. in order to push, under pressure, the polymeric body D out through the lower outlet.

According to the embodiment illustrated in figures 3E, 3F, said closing means is defined by closing bodies 54 that are in closing position of the upper outlet of the transfer chamber 50 every time the latter is in position suitably superimposed to the die cavity. When said superimposition occurs, fluid under pressure is delivered through openings 54a obtained in body 54 and directed downwards, inside the transfer chamber 50, so as to strongly push downwards the underlying polymeric body D.

Advantageously, said bodies 54 are fixed below the outer edge of a rotating support disk 36' of the second transfer machine 30 (integral and concentric with support 36 carrying the handling means 31) , that extends with such diameter that its outer edge superimposes to the path of bottom dies 21. The kinematic features of machine 30 and of the moulding machine 20 are in such relation that for each transfer chamber 50 superimposed to a cavity of bottom die 21, a closing body 54 is in closing position of the upper outlet of the transfer chamber 50; and in this step, fluid under pressure is introduced through body 54 so that the polymeric body D is "shot" downwards in the underlying bottom die cavity. According to the alternative embodiment illustrated in figures 4, 5 and 6, the upper outlet of the inner cavity 50a is closed by an upper base wall 53 that can be opened and closed (by means not shown) , integrally constrained to the transfer chamber 50. In detail, a second outer base wall 53' is provided, located at the top of wall 53 and connected thereto along the outer edge. A thin upper chamber 53a is defined between the two walls 53 and 53' extends by the entire extension of the base wall 52, which is connected to means adapted for delivering gas under pressure inside chamber 53a itself and hence through holes 57, inside the transfer chamber 50.

In particular, the upper base wall 53 is flat and, to move to the open position, it moves remaining in the same horizontal plane as it is when in closed position, moving under rotation about the vertical axis pin 531 constrained to wall 51.

In the step in which the transfer chamber 50 receives the polymeric body D from the dispensing outlet 11, the upper wall 53 is in open position whereas the lower wall 52 is in closed position; on the other hand, in the step in which the transfer chamber 50 releases the polymeric body D to the bottom die cavity, the upper wall 53 is in closed position whereas the lower wall 52 is in open position. In this step, forced fluid is introduced into the transfer chamber 50 above the polymeric body for generating a thrust directed downwards for making the output of the polymeric body (D) through the lower outlet quicker. An effect equivalent to that described above can be obtained thanks to the presence of the same fluid under pressure introduced into chamber 50 for reducing the adhesion between the polymeric body D and the inner chamber surfaces. In fact, closing chamber 50 by the upper base wall 53, after body D has been introduced in the same chamber, when fluid is introduced into the chamber itself, when the transfer chamber 50 is in portion Tl for carrying out the descent of the polymeric body D into the cavity of a bottom die 21, a certain pressure is created into chamber 50; when the lower base wall 52 is opened, the gas under pressure into chamber 50 produces a "shooting" effect that quickly and effectively pushes body D into the underlying bottom die cavity. This effect can replace or can be added to the effect described above, obtained by forced fluid delivered through the closing means 54, 53. This occurs in the embodiments illustrated in figures 4 and 5 where, in fact, the upper base wall 53 is adapted for emitting forced fluid through holes 57, whereas other fluid enters into the chamber through the side wall 51 and the lower base wall 52.

Of course, the upper outlet of the transfer chamber 50 can remain open; in this case, since the polymeric body D dimensions, in particular the diameter, are smaller than those of the cavity of bottom die 21, the polymeric body D itself can fall by gravity into said cavity. According to a different embodiment, for influencing the geometrical shape of the polymeric body D in relation to the shape of the die cavity, as an alternative or in addition to its contact with the inner surface of the transfer chamber 50 (illustrated above) , means is provided, adapted for introducing fluid under pressure into the chamber itself, acting on the side surface of the polymeric body D and/or on the lower end surface. The fluid is directed against the surface of the polymeric body D with such methods as to influence its shape. For example, the diameter of the cross section of body D is decreased, so as to make it geometrically suitable for going down into the cavity of bottom die 21 without (considerable) contact with the walls thereof. An example of embodiment is illustrated in Fig. 5, where the transfer chamber 50 is substantially equal to that of Fig. 4; however, rather than being porous, wall 51 is provided with a plurality of holes 57 of larger diameter than the pores, through which fluid under pressure (in particular air) is introduced in the inner cavity 50a. Holes 57' equal to said holes 57 can also be provided in the lower base 52. Thanks to this solution it is possible to influence the shape of body D in an adjustable manner, changing only the features of the flow introduced into chamber 50, without changing the geometrical characteristics thereof. Besides optimising the introduction of the polymeric body D in the bottom die cavity, as already mentioned above, the conditioning of its shape can advantageously be used so as to optimise its pressing, to obtain a formed item having the physical-chemical characteristics. For example, it has been found that such a shape of the polymeric body as to make it as much as possible conforming to the die cavity wherein it is introduced, so that the body adheres as much as possible to the surface of the cavity itself, gives the best results in terms of quality of the item obtained. If on the other hand, a polymeric body has a quite different shape relative to that of the cavity, for example it has such a narrow shape that its axis considerably bends, in the compression forming it undergoes localised deformations with alteration of the desired physical- chemical characteristics. With the invention it is possible to influence both the side surface and the lower end surface of the transfer chamber 50, so as to make their shape equal or almost equal to that of the corresponding surfaces of the bottom die cavity. In this case, the polymeric body D fully or almost fully adheres to the cavity and the result is that the compression forming it is subject to occurs in the optimum conditions as regards the stresses the material is subject to.

According to another embodiment of the transfer chamber 50, illustrated in Fig. 6, different means is provided for totally or partly reducing the adhesion between the polymeric body D and the inner surface of the transfer chamber 50.

In this case, chamber 50 and in particular its inner surfaces 51b, 52b are placed in vibration at such frequency values to prevent or at least partly reduce the macroscopic adhesion effect between the polymeric body D and the inner surfaces themselves. In fact, it has been found that with suitable vibration values, even though the polymeric material is sticky and at a microscopic level it produces adhesion points, these have a very small extension and above all, stay for very short times, so that the macroscopic adhesion strength between the material and the contact surface is relatively very small, and the adhesion phenomenon between such contact surface 51b and the polymeric body D is drastically reduced. In detail, in the embodiment illustrated in Fig. 6, a means 55 is applied to the outer surface of the transfer chamber 50, adapted for placing in vibration the transfer chamber 50 at such frequency values as to prevent or at least reduce, as said above, the adhesion effect between the polymeric body D and the inner surface 51b, 52b.

Excellent results have been noted with a vibration excitation acting in the plane perpendicular to the vertical axis of the transfer chamber 50, with frequency of 300 pulses a second, in the case of PET dose. A further embodiment of the transfer chamber 50 (not illustrated in the figures) , in order to totally or partly reduce the adhesion between the polymeric body D and the inner surface of the transfer chamber 50, provides for a thin coating layer covering the inner surface of cavity 50a of chamber 50, of a material having anti-adhesion properties towards the polymeric body D, for example a PTFE (Teflon ®) , whose outer surface defines said contact surface with the polymeric body D. According to a further embodiment, illustrated in Fig. 8, the side cylindrical surface that delimits the inner cavity of the transfer chamber 50 has an opening 58 on a side zone (for example for introducing body D laterally) and comprises means adapted for emitting fluid under pressure directed towards body D through said side opening 58 for influencing the shape of the body itself at this opening. In particular, the side wall of chamber 50 has a U shaped section and at the two free ends, two vertical 58a ducts are arranged, communicating through channels 58b with a source of fluid under pressure; in turn, the vertical ducts 58a are provided with several openings 58d adapted for emitting jets of fluid towards opening 58. Thus, the polymeric body D remains influenced partly by the contact (with an interposed air layer) with the side wall 51 and partly by the action of the fluid emitted through openings 58d. Of course, the means for reducing the adhesion effect between the polymeric body and the contact surface described above can be used in combination with one another.

Even though the equipment according to the invention is described and illustrated in the figures herein for transferring polymeric bodies to the bottom die cavities, it is understood that the invention can also refer to the case where such polymeric bodies are to be arranged on the upper end of a die punch, which in this case will be arranged at the bottom of the relevant bottom die, facing upwards and will, directly or not, result in a more or less protruding cavity capable of seating the polymeric body.

Of course, several practical-application changes can be made to this invention, without departing from the scope of the inventive idea as claimed hereinafter.

Claims

1 . Equipment for transferring polymeric material bodies at the melted state, to the die cavities of a moulding machine having a plurality of dies moved along an operating path, in the compression forming of items of polymeric material, characterised in that it comprises:

a plurality of transfer chambers, each adapted for containing a polymeric body and having a lower outlet for discharging the polymeric body itself, each chamber being adapted for influencing, in its inner cavity, the shape of the polymeric body according to the shape of the die cavity;

a rotating transfer machine having moving means adapted for moving the transfer chambers along a path wherein each transfer chamber moves above a die cavity for carrying out the release of the polymeric body to the cavity itself.

2. Equipment according to claim 1, characterised in that the transfer chamber comprises an inner cavity adapted for geometrically influencing, with its surface, the shape of the polymeric body.

3. Equipment according to claim 2, characterised in that the inner cavity of the transfer chamber is laterally delimited by a cylindrical side surface, whose cross size is smaller than the cross size of the side zones of the die cavity, the polymeric body being geometrically influenced by the contact with said side surface.

4. Equipment according to claim 1, characterised in that the transfer chamber (50) comprises a lower base wall (52) whose inner surface (52b) is adapted for influencing the lower end of body D, coming into contact therewith.

5. Equipment according to claim 1, characterised in that it comprises means adapted for introducing fluid under pressure into the transfer chamber (50) , acting on the surface of the polymeric body (D) so as to geometrically influence the shape of the body itself.

6. Equipment according to claim 1, characterised in that it comprises means adapted for completely or partly reducing the adhesion between the polymeric body and the inner contact surface of the transfer chamber (50) .

7. Equipment according to claim 6, characterised in that for completely or partly reducing the adhesion between the polymeric body (D) and the inner contact surface of the transfer chamber (50) , it comprises means adapted for providing fluid inside the chamber itself for forming a fluid interspace between the contact surface of the chamber itself and the polymeric body (D) .

8. Equipment according to claim 7, characterised in that the transfer chamber (50) comprises a side wall (51) and an optional lower base wall (52) which are porous so as to allow the fluid passage through them, and it further comprises means adapted for providing fluid under pressure through said porous walls (52, 51) so that the fluid itself comes out at the contact surfaces (52b, 51b) inside the transfer chamber (50) .

9. Equipment according to claim 8, characterised in that it comprises a chamber (52a, 51a) adjacent and external to said porous walls (52, 51) connected to said means adapted for providing fluid under pressure and adapted for feeding with such fluid the transfer chamber (50) through the porous walls so that it comes out at the contact surface.

10. Equipment according to claim 7, characterised in that it comprises means adapted for thermally influencing said fluid delivered between the inner surface of the chamber (50) and the polymeric body (D) .

11. Equipment according to claim 6, characterised in that for completely or partly reducing the adhesion between the polymeric body and the inner contact surface of the transfer chamber (50) , it comprises means adapted for cooling the walls of the chamber itself.

12. Equipment according to claim 6, characterised in that it comprises means (55) adapted for placing in vibration the inner surface of the transfer chamber (50) at such frequency values as to totally or partly reduce the adhesion effect between the dose (D) and the inner surface itself.

13. Equipment according to claim 6, characterised in that the inner surface of the transfer chamber (50) is covered by a material having anti-adhesion properties towards the polymeric body (D) .

14. Equipment according to claim 1, characterised in that it comprises connectable and disconnectable means adapted for preventing the descent of the polymeric body (D) from the transfer chamber (50) and alternately adapted for releasing the body itself.

15. Equipment according to claim 14, characterised in that the transfer chamber (50) comprises a lower base wall (52) adapted for taking a closing position and alternately an opening position of the lower outlet of the chamber (50) .

16. Equipment according to claim 15, characterised in that the lower base wall (52) is flat and, to move to the open position, it moves remaining in the same horizontal plane as it is when in closed position, with sliding adhering to the lower end edge of the side wall (51) .

17. Equipment according to claim 14, characterised in that it comprises means (71) , arranged below the lower edge of the side wall (51) that emit jets of fluid under pressure directed towards the lower outlet of the transfer chamber (50) adapted for keeping the polymeric body (D) suspended into the chamber (50), preventing it from going down through the lower outlet.

18. Equipment according to claim 1, characterised in that it comprises means adapted for entering forced fluid into the transfer chamber 50, above the polymeric body, adapted for generating a thrust directed downwards, for making the output of the polymeric body (D) through the lower outlet quick.

19. Equipment according to claim 18, characterised in that it comprises closing means (54) adapted for closing the upper base of the transfer chambers (50) having one or more openings (54a) and further comprises means adapted for dispensing fluid under pressure through said openings (54a) for delivering the fluid into the chamber (50) in order to push, under pressure, the polymeric body (D) out through the lower outlet.

20. Equipment according to claim 7, characterised in that it comprises an upper wall (53) adapted for closing the upper base of the transfer chambers (50) and a lower wall (52) that can be opened and closed, adapted for closing the lower outlet, said upper (53) and lower walls (52) being kept closed while fluid is introduced into the chamber itself, and the lower wall (52) being opened when the chamber is superimposed to a die cavity.

21. Equipment according to claim 1, characterised in that the side cylindrical surface that delimits the inner cavity of the transfer chamber (50) has an opening on a side zone and comprises means adapted for emitting fluid under pressure directed towards the polymeric body through said side opening for influencing the shape of the body itself at this opening.

22. Equipment according to claim 1, characterised in that the rotating transfer machine (40) has moving means adapted for moving in a succession the transfer chambers (50) along a path (P2) so that this path (P2) has a portion (Tl) concomitant with the path (P3) of the dies, during which each transfer chamber (50) is in coaxial position and above the die cavity (21) and its motion coincides with the motion of the latter, said transfer of the polymeric body (D) to the die cavity (21) being carried out in this portion (Tl) .

23. Equipment according to claim 1, characterised in that it comprises a second transfer machine (30) having a plurality of handling means (31) , adapted for pushing the polymeric body (D) and for guiding it downwards, said second transfer machine (30) being adapted for transferring single polymeric bodies from the dispensing outlet (11) to the transfer chambers (50) .

24. Equipment according to claim 23, characterised in that the moving means of the first transfer machine ( 40 ) is adapted for moving in a succession the transfer chambers (50) along a path (P2) that has a portion (T2) concomitant with a path (P4) of the handling means (31), during which each transfer chamber (50) is in coaxial position and below a handling means (31) and its motion coincides with the motion of the latter, said transfer of the polymeric body (D) to the transfer chamber (50) being carried out in this portion.

25. Equipment according to claim 23, characterised in that for transferring single polymeric bodies (D) from the dispensing outlet to said transfer chambers (50), it comprises a turntable (15) , associated to said dispensing outlet (11), carrying at the periphery a plurality of secondary dispensing outlets (16) adapted for dispensing polymeric material at the melted state, said moving means of the first transfer machine (40) being adapted for moving in a succession the transfer chambers (50) so that their path (P2) has a portion (T'2) concomitant with the path (P'4) of the secondary dispensing outlets (16), during which each transfer chamber (50) is in coaxial position and below a secondary dispensing outlet (16) and its motion coincides with the motion of the latter, the transfer of the polymeric body (D) to the transfer chamber (50) being carried out in this portion (T'2) .

26. Method for transferring dosed melted polymeric material bodies to the die cavities (21) of a moulding machine (20) having a plurality of dies moved along an operating path, in the compression forming of items of polymeric material, characterised in that it comprises

transferring the polymeric bodies (D) to the die cavities (21) by a plurality of transfer chambers (50) , each adapted for containing single bodies (D) ,

conditioning the shape of the polymeric body into the inner cavity (50a) of said transfer chamber (50) , in relation to the shape of the die cavity;

and releasing the polymeric body (D) from the transfer chamber (50) to the die cavity (21) along a path (P2) wherein each transfer chamber (50) is above the die cavity ( 21 ) .

27. Method according to claim 26, characterised in that the shape of the polymeric body (D) is geometrically influenced, while it is fully inside the transfer chamber, so as to make it geometrically suitable for going down into the die cavity without contact with the side zones of the cavity itself.

28. Method according to claim 26, characterised in that the shape of the polymeric body (D) is geometrically influenced by the contact with a side surface (51b) that laterally delimits the inner cavity (50a) of said transfer chamber (50), whose cross size is smaller than the minimum cross size of the inlet zone of the die cavity.

29. Method according to claim 26, characterised in that the shape of the polymeric body (D) is geometrically influenced with the input of fluid under pressure into the transfer chamber, acting on the side surface thereof.

30. Method according to claim 26, characterised in that for completely or partly reducing the adhesion between the polymeric body (D) and the inner contact surface of the transfer chamber (50), fluid is introduced in the chamber (50) itself so as to form a fluid interspace between the contact surface and the polymeric body (D) .

31. Method according to claim 30, characterised in that said fluid delivered between the inner surface of the chamber (50) and the polymeric body (D) is thermally conditioned.

32. Method according to claim 26, characterised in that the inner surface of the transfer chamber (50) is placed in vibration at such frequency values as to totally or partly reduce the adhesion effect between the polymeric body (D) and the inner surface itself.

33. Method according to claim 26, characterised in that it comprises the forced introduction of fluid into the transfer chamber (50), above the polymeric body, adapted for generating a thrust directed downwards, for making the output of the polymeric body (D) through the lower outlet quick.