Conveying apparatus for conveying a dose of polymeric material

Abstract

A conveying apparatus for conveying a dose of polymeric material to a receiving part of a mould comprises at least one conveying component movable along a trajectory for conveying the dose towards the receiving part of the mould. The conveying component comprises: a transfer element movable between a retracted position, in which the dose is received, and an extended position, in which the dose is transferred to the receiving part of the mould; a feed duct, in fluid communication with the transfer element. The conveying apparatus comprises a pneumatic circuit, comprising a pressure line and a vacuum line, which are in fluid communication with the feed duct, which is suitable for being alternatively connected to the pressure line, for moving the transfer element from the retracted position to the extended position; or to the vacuum line, for moving the transfer element from the extended position to the retracted position. The pneumatic circuit comprises a vacuum stabilising valve, which is positioned along the vacuum line upstream of the feed duct, which is suitable for keeping stable over time in the vacuum line a preset negative pressure value; and / or wherein the pneumatic circuit comprises a pressure stabilising valve, which is positioned along the pressure line upstream of the feed duct, which is suitable for keeping stable over time in the pressure line a preset nominal pressure value.

Description

[0001] DESCRIPTION

[0002] CONVEYING APPARATUS FOR CONVEYING A DOSE OF POLYMERIC MATERIAL

[0003] This invention relates to a conveying apparatus for conveying a dose of polymeric material.

[0004] In particular, the conveying apparatus is particularly suitable for conveying a dosed quantity of polymeric material, also called a dose, towards a receiving part of a moulding apparatus for moulding an object from the dose by compression moulding.

[0005] In prior art machines for making objects by compression moulding, use is known of a moulding apparatus comprising a first mould part and a second mould part which are suitable for operating in conjunction with each other for moulding the object.

[0006] In fact, the first mould part and the second mould part are movable relative to each other between an open position, in which the dose is rested on a receiving part of the mould, selected from either the first mould part or the second mould part and a closed position, in which the object is moulded between the first mould part and the second mould part.

[0007] For example, the first mould part may be a female mould part, provided with a moulding cavity, inside which a male element, or moulding punch, of the male mould part may be received, which is suitable for interacting with the female mould part thereby moulding the dose of polymeric material, previously positioned in the moulding cavity in order to obtain the object. The prior art machines for making objects by compression moulding dosed quantities of polymeric material comprise an extruder, for supplying the polymeric material; a plurality of moulding apparatuses each of which comprises the first mould part and the second mould part; and a conveying apparatus comprising a plurality of conveying components, each of which is suitable for conveying a dose of polymeric material from the extruder towards the receiving part of the mould along a movement trajectory.Each dose of polymeric material is separated from the extruder, which supplies the dose from the bottom upwards, by a respective conveying component which is configured to pick up the dose and to release the same dose to the receiving part of the mould by making the dose fall from above towards the receiving part of the mould.

[0008] In fact, each conveying component is provided with a lower cutting edge suitable for interacting with the continuous extrusion which comes out of the extruder. More specifically, when the conveying component passes near the extruder, the cutting edge separates from the continuous extrusion a dosed quantity of polymeric material in the melted state, also called a dose. The dose is then picked up by the conveying component and conveyed by the latter until it arrives near a mould. At this point, the conveying component releases the dose into the receiving part of the mould, so that it can be shaped between a male mould part and a female mould part to mould the object.

[0009] The cutting edge is positioned in a bottom of the conveying component. In the prior art moulding apparatuses, for example, the receiving part, for example the female mould part, is positioned below the male mould, in such a way that the moulding cavity defined in it is directed upwards.

[0010] Each conveying component is "C”- or “U”-shaped and has a retaining space, for retaining the dose, which is open in a direction of feed of the conveying component, in such a way that the dose, picked up from the extruder, is housed in this retaining space during conveying from the extruder to the moulding apparatus and is released into the receiving part of the mould by a transfer element of the conveying component.

[0011] To transfer the dose, the transfer element of the conveying component is movable between a retracted position, in which the dose is received in the retaining space, and an extended position, in which the dose is transferred to the receiving part of the mould.

[0012] To move the transfer element between the retracted position and the extended position, the conveying apparatus comprises a pneumatic circuitcomprising a pressure line and a vacuum line, which are in fluid communication with a feed duct of the conveying component, in turn in fluid communication with the transfer element.

[0013] To convey the dose, the conveying apparatus comprises a rotating conveying carrousel, on which a plurality of conveying components are fixed. In contrast, the pneumatic circuit comprises a distribution device which is fixed relative to the carrousel and is suitable for alternatively feeding the feed duct of each conveying component with pressurised air, for moving the transfer element from the retracted position to the extended position, or with negative pressure air, for moving the transfer element from the extended position to the retracted position.

[0014] The transfer element is shaped like a piston which, in the retracted position, is housed in a chamber positioned above the retaining space and which, in the extended position, extends in the retaining space to push the dose downwards.

[0015] Although the prior art conveying apparatuses are capable of operating in a satisfactory way in a large number of cases, they have some disadvantages due to the fact that the piston is not always operated effectively downwards, that is to say, from the retracted position to the extended position, and / or upwards, that is to say, from the extended position to the retracted position, due to the fact that a pressure value of the pressure line and / or a negative pressure value of the vacuum line do not remain constant over time and equal to a nominal value set at the moment when the apparatus was designed.

[0016] In fact, the pressure value and / or the negative pressure value in the respective pressure line and vacuum line may vary with changes in the external ambient temperature of the place where the apparatus is installed, or in any case various ambient and atmospheric conditions, or due to the fact that the plastic is extruded hot (at around 200°) and so consequently heats the mechanical parts which make contact with it.Moreover, over time, there may be friction between the movable part and the fixed part of the moulding apparatus, that friction also capable of heating the mechanical parts and therefore causing a change in pressure, or in vacuum in the pressure line and / or vacuum line, which in said lines results in a pressure value, or a negative pressure value, which is different from a nominal pressure value, or vacuum value.

[0017] Knobs for adjusting the value of the pressure, or of the vacuum, are present in the pressure line or in the vacuum line respectively downstream of a pressure pump, or vacuum pump, to allow an operator to manually change the nominal pressure, or vacuum values set, so as to compensate for any imbalances on the pressure line and / or vacuum line.

[0018] It is important that the negative pressure value set for the vacuum line is kept stable over time so that the piston is rapidly withdrawn inside its chamber in which it is housed. If, in fact, the piston cannot return upwards because the negative pressure value is insufficient, the next dose cannot be picked up by the same conveying component and there is a risk of a machine stop.

[0019] It is equally important that the pressure value set for the pressure line is kept stable over time, so that the piston is pushed downwards and extends in the retaining space for transferring the dose to the receiving part of the mould. Unfortunately, however, adjusting knobs are not enough to guarantee stability for a long time in the value of the pressure, or of the vacuum, fed to each piston, since the new nominal values are not maintained for long. After each new setting of a nominal pressure value, or of a nominal negative pressure value, the pneumatic circuit is in any case subject to drift and changes which render it unstable.

[0020] The technical purpose of this invention is therefore to provide a conveying apparatus for conveying a dose of polymeric material which can overcome the disadvantages of the prior art.

[0021] One aim of this invention is therefore to provide a conveying apparatus for conveying a dose to a receiving part of a mould, comprising at least oneconveying component movable in a trajectory, suitable for conveying the dose to the receiving part and wherein the conveying component comprises a dose transfer element, movable by means of a pneumatic circuit comprising a pressure line and a vacuum line, which are in fluid communication with the transfer element for moving the transfer element from the retracted position to the extended position; or for moving the transfer element from the extended position to the retracted position, wherein the transfer element can be moved in a reliable way from the extended position to the retracted position and / or from the retracted position to the extended position.

[0022] Another aim of this invention is therefore to provide a conveying apparatus for conveying a dose to a receiving part of a mould, comprising at least one conveying component movable in a trajectory, suitable for conveying the dose to the receiving part and wherein each conveying component comprises a dose transfer element, movable by means of a pneumatic circuit comprising a pressure line and a vacuum line, wherein over time the vacuum line stably maintains the same nominal negative pressure value set for it and / or over time the pressure line stably maintains the same nominal positive pressure value set for it.

[0023] The invention can be better understood and implemented with reference to the accompanying drawings, which illustrate several example, non-limiting embodiments of it, in which:

[0024] Figure 1 is a schematic top view, showing a portion of a machine for making objects by compression moulding, which comprises an extruder, a dose conveying apparatus comprising a conveying carrousel and a dose moulding apparatus, comprising a moulding carrousel;

[0025] Figure 2 is a perspective bottom view of a part of the conveying apparatus of Figure 1 comprising the conveying carrousel, on which a plurality of conveying components are fixed, amongst which it is possible to identify a plurality of even conveying components and a plurality of odd conveying components, each conveying component having a respective transferelement which is in a retracted position;

[0026] Figure 3 is an enlarged view of a detail of the conveying carrousel of Figure 2 which shows two different conveying components, among which it is possible to identify an odd conveying component and an even conveying component, wherein the transfer element of the odd conveying component, positioned upstream of the even conveying component in the direction of feed, is shown in an extended position, whilst the transfer element of the even conveying component, positioned downstream of the odd conveying component, is shown in the retracted position;

[0027] Figure 4 is a cross-section view of a conveying component and of a female mould part, along a median axial plane, wherein the conveying component and the female mould part are aligned along an axis and wherein the conveying component has picked up a dose of polymeric material but the transfer element of the conveying component is still in the retracted position, housed in a respective chamber;

[0028] Figure 5 is a cross-section view of the conveying component and of the female mould part of Figure 4, in a subsequent feed step of the conveying carrousel and of the moulding carrousel, wherein the conveying component and the female mould part are aligned along an axis and wherein the transfer element of the conveying component has been moved from the retracted position to the extended position to transfer the dose from the conveying component to the female mould part;

[0029] Figure 6 is a cross-section view of the conveying component and of the female mould part of Figure 4, in a further subsequent feed step of the conveying carrousel, wherein the dose is in a moulding cavity of the female mould part and the transfer element of the conveying component has been moved from the extended position to the retracted position to move the transfer element into the respective chamber;

[0030] Figure 7 is a schematic view of a pneumatic circuit of the conveying apparatus which comprises a pressure line, a vacuum line, and a distribution device, which is fixed relative to the conveying carrousel and isin fluid communication with the pressure line and the vacuum line in such a way as to feed pressurised air, or negative pressure air, to each conveying component, wherein the pneumatic circuit is in a state such that it keeps the transfer element of the conveying component in the retracted position; Figure 8 shows a vacuum stabilising valve of the pneumatic circuit of Figure 7;

[0031] Figure 9 is another schematic view of the pneumatic circuit of Figure 7, wherein the pneumatic circuit is in a state such that it moves the transfer element from the retracted position to the extended position;

[0032] Figure 10 shows a pressure stabilising valve of the pneumatic circuit of Figure 7, and of Figure 9.

[0033] With reference to Figures 1 to 10, the number 1 indicates a machine for making objects by compression moulding a polymeric material. The objects that the machine 1 allows to be obtained may be concave objects such as containers, caps for containers, preforms for containers, capsules for coffee, or even other types of objects.

[0034] It should be noticed that elements common to the different embodiments will be indicated with the same reference numbers.

[0035] The machine 1 , shown in Figure 1 , comprises an extruder device 2, suitable for supplying a continuous extrusion of polymeric material. In the example shown, the polymeric material comes out of the extruder device 2 in a substantially vertical outfeed direction, from the bottom upwards, but other outfeed directions are possible. For example, the polymeric material could come out of the extruder device 2 in an outfeed direction that is inclined relative to the vertical.

[0036] The extruder device 2 may be shaped to supply a continuous extrusion having a single-layer structure, that is to say, made with a single polymeric material, or alternatively to supply a multi-layer extrusion, that is to say, comprising at least two layers of polymeric materials which are different from each other.

[0037] The machine 1 also comprises a conveying apparatus 3, which includes atleast one conveying component 301 for conveying a dose 4 of polymeric material. In the example shown, a plurality of conveying components 301 is provided, only some of which were schematically shown in Figure 1.

[0038] It should be noticed that the conveying components 301 are movable along a trajectory T which in the example shown is circular. However, this condition is not necessary, and the trajectory T could be a generic closed loop trajectory, having at least one non-circular stretch.

[0039] Each conveying component 301 has a concave shape, for example a “C” shape or a “U” shape, with a concavity directed towards a direction of feed F of the conveying components 301. Each conveying component 301 therefore has a retaining space 302 defined inside it, suitable for retaining the dose 4.

[0040] Each conveying component 301 is provided with a cutting edge 303, which in the example shown is a lower edge of the conveying component 301 and is shown in Figures 2 and 3. As it passes near the outlet (not shown) of the extruder device 2, the cutting edge 303 separates the dose 4 from the continuous extrusion. The cutting edge 303 of the conveying component 301 therefore acts, in this case, as a separating element for separating the dose 4 from the continuous extrusion.

[0041] The dose 4 is then received in the retaining space 302 of the conveying component 301. The concavity which defines the retaining space 302 is internally delimited by a conveying surface 301 A to which the dose 4, which is still in a melted state, can adhere thanks to its viscosity.

[0042] It should be noticed that, as shown in Figures 1 and 4 to 6, the dose 4 has a roughly spherical shape. However, other shapes are possible for the dose 4, since the dose 4 may have the shape of a parallelepiped, or be cylindrical. The machine 1 also comprises at least one mould 5 for compression moulding the dose 4, making the desired object from it by compression moulding. In the example shown, there is a plurality of moulds 5 mounted in a peripheral region of a moulding carrousel 6, even if this condition is not necessary. Figure 1 schematically shows only a portion of the mouldingcarrousel 6, which is rotatable in a direction of movement M along a path P. Each mould 5 comprises a first mould part 501 and a second part 502, aligned with each other along a moulding line which, in the example shown, is vertical.

[0043] The first mould part 501 and the second mould part 502 are movable relative to each other, thanks to an actuator device not shown, between an open position, in which the dose 4 is received on a receiving part of the mould, selected from the first mould part 501 or the second mould part 502, and a closed position, in which the object is moulded between the first mould part 501 and the second mould part 502.

[0044] For example, the first mould part 501 may be a male mould part whilst the second mould part 502 may be a female mould part which, in the open position are spaced apart from each other, so that the mould 5 can receive the dose 4, conveyed by the conveying component 301.

[0045] It should also be specified that, in this text, the terms “upper” or “lower”, “above”, or “below” refer to a configuration of the mould 5 in which the female mould part 502 is, in use, mounted in the mould 5 and is directed towards the male mould part 501 and the axis Z is a vertical axis.

[0046] In the closed position, the female mould part 502 and the male mould part 501 are near each other, so that a moulding chamber is defined between them and in this way it is possible to mould the object into the desired shape. It should be noticed that the female mould part 502 has a moulding cavity 503, which extends around an axis Z whilst the male mould part is provided with a punch (not shown).

[0047] In the example shown in Figure 1 , the female part 502 is positioned below the male part 501. The dose 4 is transferred by the conveying component 301 when the latter is vertically aligned with the female mould part 502. In this way, the dose 4 is transferred and falls into the moulding cavity 503 of the female mould part 502 below.

[0048] In this example, the female mould part 502 is therefore the receiving part, that is to say, the mould part which receives the dose 4 to be moulded. Thisstructure of the mould 5 in which the female mould part 502 is positioned below the male mould part 501 and receives the dose 4 in the moulding cavity 503 is shown in Figures 4 to 6.

[0049] However, this condition is not necessary, since the receiving part could even be the male mould part 501 and in that case the dose 4 would fall so that it rests on and would be transferred onto the male mould part 501 , positioned below the female mould part. However, this structure of the mould 5 is not illustrated.

[0050] For the sake of simplicity, in the text below, reference will be made to the fact that the conveying apparatus 3 is configured to convey the dose 4 to a receiving part of a mould which is the female mould part 502, and in particular to transfer the dose to the moulding cavity 503 of the female mould part 502.

[0051] Each conveying component 301 , therefore, is suitable for moving along the trajectory T to convey the dose 4 towards the receiving part of a mould 502. In order to transfer the dose 4 from the conveying component 301 to the receiving part of a mould 502, each conveying component 301 comprises a transfer element 304, which is movable between a retracted position, in which the dose 4 is received in the conveying component 301 , and an extended position, in which the dose is transferred to the receiving part of a mould 502.

[0052] The transfer element 304 acts on the dose 4 and is suitable for pushing the dose 4 vertically downwards during a descent step, from the retracted position to the extended position. The transfer element 304 is suitable for returning to the retracted position, from the extended position, in a corresponding reascent step.

[0053] In order to be able to move the transfer element 304, each conveying component 301 comprises a feed duct 305, shown in Figures 4 to 6, which is in fluid communication with the transfer element 304.

[0054] In fact, the conveying apparatus 3 comprises a pneumatic circuit 7, comprising a pressure line 701 and a vacuum line 702, which are in fluidcommunication with the feed duct 305.

[0055] The feed duct 305 is suitable for being alternatively connected to the pressure line 701 , for moving the transfer element 304 from the retracted position to the extended position; or to the vacuum line 702, for moving the transfer element 304 from the extended position to the retracted position. In other words, the feed duct 305 is in fluid communication with the transfer element 304 and is in turn in fluid communication with the pressure line 701 , or with the vacuum line 702.

[0056] In this way, when the pressurised air is fed to the feed duct 305, the pressurised air is consequently fed to the transfer element 304, which is pushed downwards.

[0057] In contrast, when the negative pressure air is fed to the feed duct 305, the negative pressure air is consequently fed to the transfer element 304, which is sucked upwards.

[0058] In order to stabilise over time a negative pressure value that has been set for the vacuum line 702, the pneumatic circuit 7 may comprise a vacuum stabilising valve 703, which is positioned along the vacuum line 702 upstream of the feed duct 305, and is suitable for keeping stable over time in the vacuum line 702 a preset nominal negative pressure value.

[0059] Thanks to the presence of the vacuum stabilising valve 703 it is possible to have in the vacuum line 702 a negative pressure value which is always constant, which no longer depends on ambient and atmospheric conditions, or on the functioning of the conveying apparatus 3. The most effective stabilisation is that which follows a loss of negative pressure, since the negative pressure value on the vacuum line 702 is returned to the nominal value, originally preset.

[0060] It should also be added that, thanks to the vacuum stabilising valve 703, it is no longer necessary for an operator to manually intervene on a machine pressure gauge, since the vacuum stabilising valve 703 is capable of making the vacuum line 702 of the pneumatic circuit 7 always operate with maximum efficiency and effectiveness.Thanks to the fact that the negative pressure value on the vacuum line 702 is kept constant, equal to a nominal value, and thanks to the fact that the vacuum stabilising valve 703 is positioned on the vacuum line, upstream of the feed duct 305, a reliable reascent of the transfer element 304 from the extended position to the retracted position can be guaranteed and that allows a conveying component 301 which is ready to receive a dose 4, immediately after having released one, since it is in the retracted position. The pneumatic circuit 7 may comprise a pressure stabilising valve 705, which is positioned along the pressure line 701 upstream of the feed duct 305, which is suitable for keeping stable over time in the pressure line 701 a preset nominal pressure value.

[0061] Thanks to the presence of the pressure stabilising valve 705 it is possible to have in the pressure line 701 a pressure value which is always constant, which, as already indicated relative to the vacuum stabilising valve 703 and in a similar way, no longer depends on ambient and atmospheric conditions, or on the functioning of the conveying apparatus 3. Irrespective of other conditions, the pressure value on the pressure line 701 is returned to the nominal value, originally preset.

[0062] It should also be added that, thanks to the pressure stabilising valve 705, it is no longer necessary for an operator to manually make a correction, since the pressure stabilising valve 705 is capable of making the pressure line 701 of the pneumatic circuit 7 always operate with maximum efficiency and effectiveness.

[0063] Thanks to the fact that the pressure value on the pressure line 701 is kept constant and thanks to the fact that the pressure stabilising valve 705 may be positioned on the pressure line 701 upstream of the feed duct 305, an effective descent of the transfer element 304 from the retracted position to the extended position is guaranteed and that allows a transfer element 304 which effectively releases the dose from the conveying component 301 and transfers it to the receiving part of the mould 502.Therefore, it should be noticed that the vacuum stabilising valve 703, or the pressure stabilising valve 705, or both the vacuum stabilising valve 703 and the pressure stabilising valve 705 may be present in the pneumatic circuit 7.

[0064] This allows the obtainment of a pneumatic circuit 7 which is optimised relative to the ambient and atmospheric conditions to which the conveying apparatus 3 is subjected, since both the vacuum stabilising valve 703 and the pressure stabilising valve 705, or only one of them may be present. The vacuum stabilising valve 703 is suitable for being in fluid communication, upstream, with a vacuum source 704 and comprises a regulating valve 703A for a value of negative pressure supplied and a negative pressure sensor 703B, which is positioned downstream of the negative pressure regulating valve 703A on the vacuum line 702, the negative pressure regulating valve 703A being suitable for being controlled using feedback based on the negative pressure value measured by the negative pressure sensor 703B, for keeping the preset nominal negative pressure value stable.

[0065] Thanks to the negative pressure sensor 703B and to the control using feedback of the value of negative pressure supplied by the negative pressure regulating valve 703A, it is possible for the vacuum stabilising valve 703 to maintain the nominal negative pressure value preset at the moment when the apparatus was designed.

[0066] The pneumatic circuit 7 comprises the vacuum source 704.

[0067] It should be noticed that, if the vacuum source 704 is suitable for supplying up to a maximum negative pressure value, the nominal negative pressure value which can be preset in the vacuum stabilising valve 703 is less than said maximum negative pressure value.

[0068] The pressure stabilising valve 705 is suitable for being in fluid communication, upstream, with a pressure source 706 and comprises a regulating valve 705A for a pressure value and a pressure sensor 705B, which is positioned downstream of the pressure regulating valve 705A onthe pressure line 701 , the pressure regulating valve 705A being suitable for being controlled using feedback based on the pressure value measured by the pressure sensor 705B, for keeping the preset nominal pressure value stable.

[0069] Thanks to the pressure sensor 705B and to the control using feedback of the value of pressure supplied by the pressure regulating valve 705A, it is possible for the pressure stabilising valve 705 to maintain the nominal pressure value preset at the moment when the apparatus was designed. The pneumatic circuit 7 comprises the pressure source 706.

[0070] It should be noticed that, if the pressure source 706 is suitable for supplying up to a maximum pressure value, the nominal pressure value which can be preset in the pressure stabilising valve 705 is less than said maximum pressure value.

[0071] The conveying apparatus 3 comprises a conveying carrousel 307 for conveying the dose 4 on which a plurality of conveying components 301 are fixed, in a peripheral region of conveying carrousel 307. The conveying carrousel 307 is rotatable in the direction of feed F, as shown in Figures 1 to 3.

[0072] Among the conveying components 301 of the conveying apparatus 3 it is possible to identify odd conveying components 30T and even conveying components 301”.

[0073] Each even conveying component 301” is interposed between two odd conveying components 30T and each odd conveying component 30T is interposed between two even conveying components 301”, since the even conveying components 301 ” are alternated with odd conveying components 301’.

[0074] The pneumatic circuit 7 comprises a distribution device 713, which is fixed relative to the conveying carrousel 307 and is in fluid communication with the pressure line 701 and the vacuum line 702 in such a way as to feed pressurised air, or negative pressure air, to each conveying component 301. However, in order to guarantee greater efficiency, the distribution devicecomprises an odd distribution element, suitable for feeding the odd conveying components 301’ of the plurality of conveying components 301 and an even distribution element, suitable for feeding the even conveying components 301 ” of the plurality of conveying components 301.

[0075] The feed duct 305 of each odd conveying component 301’ is in fluid communication with the odd distribution element, whilst the feed duct 305 of each even conveying component 301” is in fluid communication with the even distribution element.

[0076] In this way, an odd conveying component 30T and an even conveying component 301” can simultaneously be in fluid communication, thereby guaranteeing that each conveying component 301 , whether it is an odd conveying component 30T or an even conveying component 301”, can be fed with the pressurised fluid for longer, when that is necessary, in particular for moulding machines with particularly high performance in terms of production, which require a conveying apparatus 3 rotatable at high speed. In such conveying apparatuses 3, in which the conveying carrousel 307 reaches high speeds of rotation, the even distribution element and the odd distribution element may be necessary.

[0077] However, it should be specified that even a single distribution device may be present, capable of feeding pressurised air, or negative pressure air, to each conveying component 301. In this case, all of the conveying components 301 are fed in sequence, one after another. In other words, the even distribution element and the odd distribution element may not be necessary, for conveying apparatuses 3 in which the conveying carrousel 307 is designed to rotate with a speed of rotation which is such that it is not necessary to guarantee very high productivity.

[0078] The odd distribution element comprises an odd descent slot 707 for moving the transfer element 304 of an odd conveying component 301’ from the retracted position to the extended position and an odd selecting valve 708, suitable for receiving the pressure line 701 and the vacuum line and in fluid communication with the odd descent slot 707.The odd selecting valve 708 is positioned to alternatively enable the pressure line 701 , or the vacuum line 702 at the odd descent slot 707. In other words, the odd selecting valve 708 allows the odd descent slot 707 to be selectively connectable to the pressure line 701 , or to the vacuum line 702.

[0079] The odd distribution element comprises an odd reascent slot 709, for moving the transfer element 304 of the odd conveying component 301 ’ from the extended position to the retracted position, wherein the odd reascent slot 709 is in fluid communication with the vacuum line 702.

[0080] It should be noticed that the transfer element 304 of an odd conveying component 301’ may be moved from the retracted position to the extended position when an infeed end 305A of the respective feed duct 305 is facing the odd descent slot 707 and, vice versa, may be moved from the extended position to the retracted position when the infeed end 305A of the respective feed duct 305 is facing the odd reascent slot 709.

[0081] Figures 4 to 6 show, by way of example, the transfer of the dose 4 from an odd conveying component 301 ’ to the female mould part 502 and it can be seen how, when the odd conveying component 30T is above the female mould part 502, the axis Z of the female mould part 502 coincides with the axis of the conveying component 301. However, this also applies to any conveying component 301 , whether it is odd 30T or even 301 ”, since even when the dose 4 is transferred by the even conveying component 301” and the even conveying component 301” is above the female mould part 502, the axis Z of the female mould part 502 coincides with the axis of the conveying component 301”.

[0082] In this way, the dose 4 is transferred and falls into the moulding cavity 503 of the female mould part 502 below.

[0083] As shown in Figures 4 e 5, which show the odd conveying component 301 ’, it can be seen how the infeed end 305A of the feed duct 305 is facing the odd descent slot 707.

[0084] In contrast, in Figure 6, the infeed end 305A of the feed duct 305 is facingthe odd reascent slot 709.

[0085] In fact, the distribution device 713 is shaped like a plate which has the odd descent slot 707 and the odd reascent slot 709, which extend along a same circle but on different respective angular sectors. The odd descent slot 707 and the odd reascent slot 709 are, in fact, shaped like ducts made in a body (not illustrated) of the distribution device 713.

[0086] Each odd conveying component 301 ’, rotating along the trajectory T, is such that the infeed end 305A is first facing the odd descent slot 707 and, then, facing the odd reascent slot 709.

[0087] However, when the odd conveying component 30T is facing the odd descent slot 707 it is still, initially, subjected to the negative pressure air, as shown in Figure 4 and in Figure 7 and therefore the transfer element 304 is in the retracted position.

[0088] In fact, it is the odd selecting valve 708 which is suitable for enabling, when the odd conveying component 30T is in the odd descent slot 707, the supplying of pressurised air to the odd descent slot 707 for moving the transfer element 304 from the retracted position to the extended position, as shown in Figure 5 and in Figure 9.

[0089] It follows that the transfer element 304 of the odd conveying component 301 ’ is moved from the retracted position to the extended position when the infeed end 305A of the respective feed duct 305 is facing the odd descent slot 707 but, in addition, the pressure line 701 is enabled by the odd selecting valve 708.

[0090] When the infeed end 305A of the respective feed duct 305 is in contrast facing the odd reascent slot 709, as shown in Figure 6, the transfer element 304 is directly fed with negative pressure air, the odd reascent slot 709 always being connected to the vacuum line 702, and therefore the transfer element 304 is moved from the extended position to the retracted position. The even distribution element comprises an even descent slot 710 for moving the transfer element 304 of an even conveying component 301” from the retracted position to the extended position and an even selectingvalve 711 , suitable for receiving the pressure line 701 and the vacuum line 702 and in fluid communication with the even descent slot 710.

[0091] The even selecting valve 711 is positioned to alternatively enable the pressure line 701 , or the vacuum line 702 at the even descent slot 710. In other words, the even selecting valve 711 allows the even descent slot 710 to be selectively connectable to the pressure line 701 , or to the vacuum line 702.

[0092] The even distribution element comprises an even reascent slot 712, for moving the transfer element 304 from the extended position to the retracted position, but the even reascent slot 712 is in fluid communication with the vacuum line 702.

[0093] It should be noticed that the even descent slot 710 and the even reascent slot 712 extend along a same further circle but on different respective angular sectors. The even descent slot 710 and the even reascent slot 712 are also shaped like ducts made in the body of the distribution device 713. The further circle on which the even descent slot 710 and the even reascent slot 712 extend is different from the circle along which odd descent slot 707 and the odd reascent slot 709 extend, but the circle and the further circle are concentric in such a way that the angular sector on which the odd descent slot 707 and the even descent slot 710 are located is the same and in such a way that the further angular sector on which the odd reascent slot 709 and the even reascent slot 712 are located is the same.

[0094] Each even conveying component 301”, rotating along the trajectory T, is such that the infeed end 305A is first facing the even descent slot 710 and, then, facing the even reascent slot 712.

[0095] However, when the even conveying component 301” is facing the even descent slot 710 it is still, initially, subjected to the negative pressure air and therefore the transfer element 304 is in the retracted position, as shown in Figure 7.

[0096] In fact, it is the even selecting valve 711 which is suitable for enabling, when the even conveying component 301” is in the even descent slot 710, thesupplying of pressurised air to the even descent slot 710 for moving the transfer element 304 from the retracted position to the extended position, as shown in Figure 9.

[0097] It follows that the transfer element 304 of the even conveying component 301” may be moved from the retracted position to the extended position when the infeed end 305A of the respective feed duct 305 is facing the even descent slot 710 but, in addition, the pressure line 701 is enabled by the even selecting valve 711.

[0098] When the infeed end 305A of the respective feed duct 305 is in contrast facing the even reascent slot 712, the transfer element 304 may be directly fed with negative pressure air, the even reascent slot 712 always being connected to the vacuum line 702, and therefore the transfer element 304 may be withdrawn from the extended position to the retracted position. It should be noticed that each conveying component 301 , whether it is identified as an odd conveying component 301 ’ or as an even conveying component 301”, comprises a chamber 306 positioned above the retaining space 302 and axially aligned with the retaining space 302, which is suitable for housing inside it the transfer element 304.

[0099] In the retracted position the transfer element 304 is entirely axially contained in the chamber 306, whilst in the extended position it projects from the chamber 306 in such a way that it is in contact with the dose 4, for transferring the dose 4 to the receiving part of the mould 502.

[0100] Figures 4 to 6 show how the transfer element 304 is shaped like a hollow piston which has a thrust wall, which is positioned flush with an end surface of the conveying component 301 , when the piston is contained in the chamber 306.

[0101] Figure 2 shows how, if the transfer element 304 is in the retracted position, the thrust wall does not project from the end surface of the conveying component 301.When the piston is in the extended position, the thrust wall is in contrast configured to engage with the dose 4 in such a way as to push the dose 4 downwards.

[0102] The thrust wall delimits a final part of the piston, which is directed, in use, towards the receiving part of the mould 502. The final part of the piston is shaped like a hollow cylinder. The final part of the piston has a cross-section with dimensions smaller than a cross-section of the chamber 306. In fact, the piston also has an initial part, with a concave shape, which has a crosssection greater than the cross-section of the final part and is shaped to engage with the walls of the chamber 306. The initial part of the piston, with a concave shape, is in fluid communication with the duct 305 and in particular with an outfeed end 305B of the duct 305.

[0103] In this way, when the pressurised air, or the negative pressure air is fed to the feed duct 305 and reaches the outfeed end 305B, which is in fluid communication with the initial part of the piston, the pressurised air, or negative pressure air, may fill the cavity defined inside the piston, to move it so that it performs its descent, or reascent.

[0104] Thanks to the fact that the piston 304 has a hollow shape and thanks to the fact that it is fed with pressurised air from the pressure line 701 or with negative pressure air from the vacuum line 702, which are kept stable, respectively thanks to the pressure stabilising valve 705 and / or to the vacuum stabilising valve 703 at a preset, nominal pressure, or negative pressure value, there is a guaranteed reliable movement of the piston 304 from the extended position to the retracted position, for making the piston return into its relative chamber 306 and / or from the retracted position to the extended position, for transferring the dose 4 to the receiving part of the mould 502.

Claims

CLAIMS1. A conveying apparatus (3) for conveying a dose (4) of polymeric material to a receiving part of a mould (502) comprising:- at least one conveying component (301 ) movable along a trajectory (T) for conveying the dose (4) towards the receiving part of the mould;- wherein the conveying component (301) comprises: a transfer element (304) movable between a retracted position, in which the dose (4) is received, and an extended position, in which the dose (4) is transferred to the receiving part of the mould; a feed duct (305), in fluid communication with the transfer element (304);- wherein the conveying apparatus (3) comprises a pneumatic circuit (7), comprising a pressure line (701) and a vacuum line (702), which are in fluid communication with the feed duct (305);- the feed duct (305) being suitable for being alternatively connected to the pressure line (701 ), for moving the transfer element (304) from the retracted position to the extended position; or to the vacuum line (702), for moving the transfer element (304) from the extended position to the retracted position;- wherein the pneumatic circuit (7) comprises a vacuum stabilising valve (703), which is positioned along the vacuum line (702) upstream of the feed duct (305), which is suitable for keeping stable over time in the vacuum line (702) a preset nominal negative pressure value and / or- wherein the pneumatic circuit (7) comprises a pressure stabilising valve (705), which is positioned along the pressure line (701 ) upstream of the feed duct (305), which is suitable for keeping stable over time in the pressure line (701) a preset nominal pressure value.

2. The apparatus (3) according to claim 1 , wherein the vacuum stabilising valve (703) is suitable for being in fluid communication, upstream, with a vacuum source (704) and comprises a regulating valve (703A) for a value of negative pressure supplied and a negative pressure sensor (703B), which is positioned downstream of the negative pressure regulating valve (703A)on the vacuum line (702), the negative pressure regulating valve (703A) being suitable for being controlled using feedback based on a negative pressure value measured by the negative pressure sensor (703B) for keeping the preset nominal negative pressure value stable.

3. The apparatus (3) according to claim 1 , or 2, wherein the pressure stabilising valve (705) is suitable for being in fluid communication, upstream, with a pressure source (706) and comprises a regulating valve (705A) for a value of pressure supplied and a pressure sensor (705B), which is positioned downstream of the pressure regulating valve (705A) on the pressure line (701), the pressure regulating valve (705A) being suitable for being controlled using feedback based on the pressure value measured by the pressure sensor (705B) for keeping the preset nominal pressure value stable.

4. The apparatus (3) according to one of the preceding claims, and comprising a rotatable conveying carrousel (307) for conveying the dose (4), on which a plurality of conveying components (301) are fixed, and wherein the pneumatic circuit (7) comprises a distribution device (713), which is fixed relative to the conveying carrousel (307), which is suitable for feeding pressurised air, or negative pressure air, to each conveying component (301); wherein the distribution device (713) comprises an odd distribution element (707; 708; 709), suitable for feeding odd conveying components (301’), identified among the plurality of conveying components (301 ), and an even distribution element (710; 711 ; 712), suitable for feeding even conveying components (301”) identified among the plurality of conveying components (301); and wherein the feed duct (305) of each odd conveying component (301’) is in fluid communication with the odd distribution element (707; 708; 709), and the feed duct of each even conveying component (301”) is in fluid communication with the even distribution element (710; 711 ; 712).

5. The apparatus (3) according to claim 4, and wherein the odd distribution element (707; 708; 709), comprises an odd descent slot (707) for movingthe transfer element (304) of an odd conveying component (301’) from the retracted position to the extended position and an odd selecting valve (708), suitable for receiving the pressure line (701) and the vacuum line (702) and in fluid communication with the odd descent slot (707), wherein the odd selecting valve (708) is positioned to alternatively enable the pressure line (701), or the vacuum line (702) at the odd descent slot (707); and wherein the odd distribution element (707; 708; 709) comprises an odd reascent slot (709), for moving the transfer element (304) from the extended position to the retracted position, wherein the odd reascent slot (709) is in fluid communication with the vacuum line (702).

6. The apparatus (3) according to claim 5, and wherein the transfer element (304) of the odd conveying component (301’) is moved from the retracted position to the extended position when an infeed end (305A) of the respective feed duct (305) is facing the odd descent slot (707) and the pressure line (701) is enabled by the odd selecting valve (708); and is moved from the extended position to the retracted position when the infeed end (305A) of the respective feed duct (305) is facing the odd reascent slot (709).

7. The apparatus (3) according to one of claims 4 to 6, and wherein the even distribution element (710; 711 ; 712), comprises an even descent slot (710) for moving the transfer element (304) of an even conveying component (301”) from the retracted position to the extended position and an even selecting valve (711), suitable for receiving the pressure line (701) and the vacuum line (702) and in fluid communication with the even descent slot (710), wherein the even selecting valve (711) is positioned to alternatively enable the pressure line (701 ), or the vacuum line (702) at the even descent slot (710); and wherein the even distribution element (710; 711 ; 712) comprises an even reascent slot (712), for moving the transfer element (304) from the extended position to the retracted position, wherein the even reascent slot (712) is in fluid communication with the vacuum line (702).

8. The apparatus (3) according to claim 7, and wherein the transfer elementposition to the extended position when an infeed end (305A) of the respective feed duct (305) is facing the even descent slot (710) and the pressure line (701) is enabled by the even selecting valve (711); and is moved from the extended position to the retracted position when the infeed end (305A) of the respective feed duct (305) is facing the even reascent slot (712).

9. The apparatus (3) according to one of the preceding claims, wherein the conveying component (301 ) is “C”- or “U”-shaped and has a retaining space (302) for retaining the dose (4), which is open in a direction of feed (F) and is suitable for picking up the dose (4) from an extruder (2) and for housing the dose (4) in the retaining space (302) until the dose (4) is transferred to the receiving part of the mould.

10. The apparatus (3) according to claim 9, wherein the conveying component (301 ) comprises a chamber (306) positioned above the retaining space (302) and axially aligned with the retaining space (302), which is suitable for housing inside it the transfer element (304) in such a way that in the retracted position the transfer element (304) is entirely axially contained in the chamber (306) and that in the extended position it projects from the chamber (306) and is in contact with the dose (4), for transferring the dose (4) to the receiving part of the mould.

11. The apparatus (3) according to claim 10, wherein the transfer element (304) is shaped like a hollow piston which has a thrust surface which is positioned flush with an end surface of the conveying component (301), when the transfer element (304) is contained in the chamber (306).

12. The apparatus (3) according to claim 11 , wherein the thrust surface is configured to engage with the dose (4), when the transfer element (304) is in the extended position.

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