WO2005102646A1

WO2005102646A1 - Machine and method for transferring melted polymeric material bodies

Info

Publication number: WO2005102646A1
Application number: PCT/IB2005/001005
Authority: WO
Inventors: Fiorenzo Parrinello; Zeno Zuffa; Maurizio Borgatti; Alessandro Balboni; Matteo Camerani
Original assignee: Sacmi Cooperativa Meccanici Imola Societa' Cooperativa
Priority date: 2004-04-23
Filing date: 2005-04-15
Publication date: 2005-11-03

Abstract

Machine comprising a plurality of handling means (50, 3:1), each having a contact surface (51b, 32b) with the polymeric body (D), adapted for holding by contact and pulling in movement the polymeric body (D) itself, moving means (41, 46, 36) adapted for moving said handling means (50, 31) along at least one portion of path (P2, P4) comprised between a dispensing point of the polymeric body (D) and a die cavity (21), means adapted for forming a fluid interspace along said contact surface (51b, 32b) such as to totally or partly reduce the adhesion effect between the polymeric body (D) and the contact surface (51b, 32b) itself.

Description

MACHINE AND METHOD FOR TRANSFERRING MELTED POLYMERIC MATERIAL BODIES

TECHNICAL FIELD The present invention relates to a method and a machine 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 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 forming 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 machine 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 dies when such bodies have a relatively large mass and length and therefore a sufficiently long time is needed for carrying out such transfer; this is the case when items like the PET (polyethyleneterephthalate) pre-forms currently used on the market are to be formed for manufacturing (by the known stretch-blowing operation) the usual plastic bottles.

The technical problems existing in the transfer of relatively large mass doses to the die cavities are mainly caused by the material features in combination with the fact that such bodies are to be handled at relatively very high speeds, like those of current continuously rotating moulding machines.

In fact, the polymeric material the does are formed with tends to adhere to the surfaces of the handling means it comes into contact with, due to its physical state: more or less viscous liquid at a relatively high temperature (usually more 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. Moreover, said adhesion problems are strongly increased by the fact that the descent by sliding of the polymeric body along the surfaces that handle it occurs while such surfaces moves continuously, in synchronism with the movement of the moulding machine, along a closed path, and moreover, at relatively high speed, and as a consequence, in the presence of a harmful centrifugal effect.

It should be said that in the contact of the polymeric body with the contact surface, 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 said 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 therefore 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.

To solve the technical problems described above, a moulding machine was proposed (patent application WO 03/047834) wherein the dose handling is avoided. In fact, these are dispensed out of an extruder and released by gravity, directly into the die cavities. To this end, the extruder comprises 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. A technology capable of meeting the requirements described is therefore needed.

DISCLOSURE OF INVENTION

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

Said and other objects are achieved by the invention as characterised in the claims. As a general line, the invention provides for handling the polymeric bodies at the melted state by a plurality of handling means, each having a contact surface with the polymeric body adapted for holding the polymeric body by contact and pulling it therewith in movement while a fluid interspace is formed along said contact surface such as to fully or partly reduce the adhesion effect between the polymeric body and the inner surface itself; moreover, at the same time, moving means are adapted for moving the handling means along at least one portion of the path comprised between a dispensing point of the polymeric body and a die cavity.

The contact surface has a general inclination with vertical component (that is, it ha generatrices with vertical component) and the movement of the handling means has speed with horizontal component. In particular, said fluid is a gas, preferably air. However, it can be a different gas, for example nitrogen, carbon dioxide or else.

Said fluid interspace is produced by delivering fluid through the portion of the handling means where the contact surface is located so that the fluid comes out of the same surface distributed thereon. To this end, the portion of said handling means where the contact surface is arranged exhibits passages distributed on the contact surface through which the fluid is fed and made to come out. These fluid passages must be relatively small and numerous, distributed on the contact surface. According to a preferred embodiment, the contact surface is arranged on a wall made of a porous material such as to allow the fluid passage through it. Means adapted for delivering fluid is applied on the porous wall so that it passes through the wall itself coming out at the contact surface.

As an alternative to the 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 occurs; for example, such holes can have a helical distribution to obtain the maximum coverage on the contact zone. According to a further option, 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 separation relatively thin, shaped and distributed in an appropriate manner on the contact zone, through which the fluid passage is carried out.

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, it is possible to totally or at least partly reduce the effect of adhesion of the polymeric body 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 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 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 technical 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 even avoid any contact. 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, so as to decrease the temperature of the surface of the polymeric body and/or of the contact surface.

The cooled fluid, passing through the wall, or simply touching both the contact surface and the surface of the polymeric body, decreases at least in surface their temperature, thus increasing the viscosity of the polymeric body, 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. The cooling effect of the fluid is totally different from that obtained by relatively long physical contact 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 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 body of polymeric material and the handling means of said body, a strong and relatively deep cooling occurs, limited to a relatively small body portion, with harmful consequences for the formed item, as mentioned above. Another favourable effect produced by the fluid is that it prevents the penetration of the polymeric material into the pores or other apertures provided on the contact surface. The invention will be described in detail hereinafter with reference to the accompanying drawings, which show some exemplifying and non-limiting embodiments of the invention.

For clarity it is stated that the term "contact surface" used to describe and claim the present invention, means the surface that tends to come into contact with the polymeric body and that the contact occurs the described fluid interspace being interposed.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows a schematic plan view of an 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 shows an enlarged view of the equipment 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 shows a schematic, axial section, vertical elevation view of a particular embodiment of the transfer chamber of the first transfer machine of Fig. 2.

Fig. 4A shows the section according to plane A- A of Fig.

4.

Fig. 5 shows a schematic, axial section, vertical elevation view of a different embodiment of the transfer chamber of Fig. 4.

Fig. 6 shows a schematic, axial section, vertical elevation view of a further different embodiment of the transfer chamber of Fig. 4.

Fig. 7 shows a perspective view of an embodiment of the handling means 31 of the second transfer machine 30 for transferring single polymeric bodies from the dispensing outlet to the transfer chambers, in the equipment of Fig.

2.

Fig. 8 shows a top plan view of Fig. 7. Fig. 9 shows the section according to plane X-X of Fig. DETAILED DESCRIPTION OF INVENTION.

The equipment illustrated in figures from 1 to 3F comprises a first transfer machine, globally indicated with reference numeral 40, adapted for transferring polymeric bodies D to the die cavities of a moulding turntable 20 rotating with continuous movement, and a second transfer machine, globally indicated with reference numeral 30, adapted for transferring polymeric bodies D from the fixed dispensing outlet 11, of an extruder means 10 of polymeric material, to suitable means of the first transfer chamber. The first transfer chamber 40 forms a first embodiment of the invention, whereas the second transfer chamber 30 forms a second embodiment of the invention. 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 element 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.

The first transfer machine 40, made according to the first embodiment of the invention, comprises a plurality of handling means 50, each having a contact surface 51b with the polymeric body D adapted for holding by contact and pulling with it in movement the polymeric body itself, for transferring the polymeric bodies D, coming from the fixed dispensing outlet 11, to the cavities of bottom dies 21. In particular, said handling means 50 defines a transfer chamber having a lower outlet and an upper outlet for the passage of the polymeric body, adapted for containing a polymeric body D, and for transferring it afterwards to the cavity of a bottom die 21; the side surface 51b of chamber 50 is a cylindrical surface with closed section that defines the contact surface with the polymeric body D.

According to the embodiment illustrated in figures from 1 to 3F, the first transfer machine 40 is rotating about a vertical axis and 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, through its lower outlet, 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 TI concomitant with path P3 of the dies, 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 TI 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; of 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 machine, 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 TI 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 TI from chambers 50 to the cavities of bottom dies 21. By providing a suitable length for portion TI concomitant with paths P2 and P3, thanks to the coincidence of the movements in such portion TI, a relatively high time is provided (depending on the rotation speed of the moulding machine 20 and on the length of the concomitance portion TI) 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 TI 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 TI 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 die cavities in one point only. The second transfer machine 30 illustrated in the figures forms a second embodiment of the invention. This machine 30 comprises a plurality of handling means 31, each having a contact surface 32b with the polymeric body, adapted for holding by contact and pulling with it in movement the polymeric body itself.

Means 31 moves the polymeric bodies D moving them from the fixed point from where they come out (the dispensing outlet 11) and transferring them, with movement having horizontal component, to the transfer chambers 50. According to the embodiment illustrated in figures from 1 to 3D and from 7 to 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 extruded element 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 45A, 45B, 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 by which it is pushed by contact in horizontal motion. 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 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 TI. As an alternative to the second transfer machine 30 described above, means can be provided, for transferring the polymeric bodies D from the dispensing outlet 11 to the transfer chambers 50 of the first transfer machine, 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. In particular, a turntable can be provided (in se known and not illustrated in the figures) , carrying at the periphery a plurality of mobile dispensing outlets, carried by a machine rotating about a vertical central axis, adapted for dispensing polymeric material at the melted state, while they move along a circular path laying on a horizontal plane.

In this case, the handling means of the transfer chambers 50 moves in a succession such chambers 50 so that their path has a portion concomitant with the path of the mobile dispensing outlets, during which each transfer chamber 50 is in coaxial position and below a secondary outlet and its motion coincides with the motion of the latter; the transfer of the polymeric body D is carried out in this portion to the transfer chamber 50. According to the first embodiment of the invention, 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 adapted for forming a fluid interspace along the contact surface 51b such as to totally or partly reduce the adhesion between the polymeric body and the contact surface itself.

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. 6, 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, 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 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. This solution with annular duct 71 can be perfectly applied also to transfer chambers whose side wall 51 is passed through by fluid as in the embodiments illustrated in figures 4 and 5.

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. 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.

Preferably, 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 the contact being such as to hinder the descent, and therefore to properly introduce it into the bottom die cavity. In particular, while it is fully into the transfer chamber, the polymeric body takes the desired reshaped shape which it keeps while moving from the transfer chamber to the die cavity; this shape is such that it allows it to penetrate into this 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 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, 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 TI 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 4, 6, 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 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 -5, 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 or less centrifugal movement. According to another 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 an alternative embodiment illustrated in figures 4 and 5, 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 521 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 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 of the transfer chamber 50, 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 the second embodiment of the invention, since the polymeric body D comes into contact with the inner surface of the handling means 31, especially with the inner surface 32b, means 31 comprises means adapted for forming a fluid interspace along the contact surface 32b such as to totally or partly reduce the adhesion effect between the polymeric body and the contact surface itself. In the embodiment of the handling means 31 illustrated in figures from 7 to 9 said inner surface 32b, which defines the contact surface, has a constant cross section and substantially vertical generatrices, and the polymeric body D slides guides and pulled along it. The lower end portion 33 of wall 32 can be circular and closed and have an axial section slightly converging downwards. Means 31 comprises means adapted for forming a fluid interspace (especially a gas) along the inner surface 32b such as to totally or partly reduce the adhesion effect between the polymeric body D and the inner surface itself .

In particular, the curved wall 32 (comprised its lower portion 33) is porous so as to allow the gas passage through it, and moreover it comprises a second tubular wall 320 external and coaxial to the curved wall 32, and connected thereto with its upper and lower ends. A chamber 34 is defined between the two walls 32 and 320 which surrounds the porous curved wall 32, and extends by the entire or almost the entire length thereof, which is connected to means 38 (only partly shown in Fig. 9) adapted for delivering gas under pressure inside chamber 34 itself, which gas comes out at the contact surface 32b. Chamber 34 is divided into an upper portion 34' and a lower portion 34 respectively fed by a duct 35' and by a duct 35", which ducts are separate so as to allow the delivery in the two portions of chamber 34 of fluids having different (pressure) characteristics, so as to better control the descent of item D. Excellent results have been obtained with a wall 32 formed with a porous material having the features illustrated above with reference to the transfer chamber 50. Moreover, similarly to what said above, means (not shown in the figures) can be provided, adapted for thermally influencing the gas so as to decrease its temperature, with the features and the results described above .

As an alternative, the gas may be delivered on the contact surface 32b with a flow directed in tangent manner to the surface itself, so as to develop an interspace that touches the surface itself. The provision of a fluid interspace between the contact surface 32b of the handling means 31 and the polymeric body D produces the favourable effects described in detail hereinafter with reference to the transfer chamber 50.

Even though the machine 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.

Besides the use of means adapted for forming a fluid interspace, other means can be used for reducing the adhesion effect between the polymeric body and the contact surface, such as anti-adhesion surface coatings or means capable of placing in vibration the contact surface .

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. Machine for transferring polymeric material bodies at the melted state to the die cavities of a rotating and continuous moulding machine in the compression forming of plastic items, characterised in that it comprises:

a plurality of handling means, each having a contact surface with the polymeric body, adapted for holding by contact and pulling with it in movement the polymeric body itself,

moving means adapted for moving said handling means along at least one portion of path comprised between a dispensing point of the polymeric body and a die cavity,

means adapted for forming a fluid interspace along said contact surface such as to totally or partly reduce the adhesion effect between the polymeric body and the contact surface itself.

2. Machine according to claim 2, characterised in that said contact surface has a general inclination with vertical component and the movement of the handling means has speed with horizontal component.

3. Machine according to claim 1, characterised in that said fluid is a gas.

4. Machine according to claim 1, characterised in that said contact surface exhibits passages distributed on the surface itself through which the fluid is fed and made to come out by the means adapted for forming the fluid interspace .

5. Machine according to claim 4, characterised in that the handling means comprises a contact wall where the contact surface is arranged, which is porous and adapted for allowing the fluid passage through it, and further comprises means adapted for providing fluid applied to the porous wall so that the fluid passes through the wall itself coming out at the contact surface.

6. Machine according to claim 5, characterised in that the handling means comprises a closed chamber that surrounds the contact wall, and extends by the entire or almost the entire length thereof, which is connected with means adapted for delivering fluid under pressure into the chamber itself, said fluid coming out at the porous contact surface.

7. Machine according to claim 1, characterised in that it comprises means adapted for thermally influencing said fluid so that it decreases the temperature of the surface of the polymeric body and/or of the contact surface.

8. Machine according to claim 2, characterised in that each handling means defines a transfer chamber adapted for containing a polymeric boy, having a lower mouth and an upper mouth for the passage of the polymeric body, whose side surface is a cylindrical surface that defines the contact surface with the polymeric body.

9 . Machine according to claim 8, characterised in that said handling means is moved by 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.

10. Machine according to claim 8, characterised in that said transfer chamber has an upper outlet for receiving a polymeric body through it and a lower outlet for discharging the polymeric body itself through it

11. Machine according to claim 8, 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) .

12. Machine according to claim 1, characterised in that the transfer chamber comprises an inner cavity adapted for geometrically influencing the shape of the polymeric body in relation to the die cavity shape.

13. Machine according to claim 12, 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.

14. Machine 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.

15. Machine according to claim 1, characterised in that the transfer chamber 1 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.

16. Machine according to claim 15, 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).

17. Machine according to claim 15, 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. Machine according to claim 8, 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. Machine 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. Machine according to claim 18, 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. Machine according to claim 2, characterised in that the contact surface is concave and open on a side and is arranged with its concavity facing the direction of forward movement of the handling means.

22. Machine according to claim 21, characterised in that the lower end portion 33 of the contact wall 31 is circular and closed and have an axial section slightly converging downwards .

23. Machine according to claim 21, characterised in that the handling means is moved by 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 chamber (50).

24. Method for transferring polymeric material bodies at the melted state to the die cavities of a rotating and continuous moulding machine for the compression forming of plastic items, characterised in that it comprises:

holding by contact and pulling in movement the polymeric body by a handling means having a contact surface with the polymeric body itself, by the movement of the handling means along at least one portion of the path comprised between a dispensing point of the polymeric body and a die cavity,

forming at the same time a fluid interspace along said contact surface such as to totally or partly reduce the adhesion effect between the polymeric body and the inner surface itself.

25. Method according to claim 24, characterised in that said contact surface has a general inclination with vertical component and the movement of the handling means has speed with horizontal component.

26. Method according to claim 24, characterised in that said fluid is a gas.

27. Method according to claim 24, characterised in that said fluid is delivered through the portion of the handling means where the contact surface is located so that the fluid itself comes out of the same contact surface distributed thereon.

28. Method according to claim 27, characterised in that the fluid is made to pass through a porous wall that carries said contact surface, being made to come out at the contact surface itself.

29. Method according to claim 24, characterised in that said fluid delivered between the contact surface and the polymeric body is thermally influenced so as to decrease the temperature of the surface of the polymeric body and/or of the contact surface.

30. Method according to claim 24, wherein said handling means defines a transfer chamber, adapted for containing a polymeric body, whose side surface is a cylindrical surface, with closed section that defines the contact surface with the polymeric body characterised in that the shape of the polymeric body (D) is geometrically influenced by the transfer chamber (50) , in relation to the die cavity shape.

31. Method according to claim 30, 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.

32. Method according to claim 24, wherein said handling means defines a transfer chamber (50), adapted for containing a polymeric body, 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 to make the output of the polymeric body (D) through the lower outlet quicker.