Title of Invention	METHOD OF MAKING CONCAVE OBJECTS IN POLYMERIC MATERIAL AND MOLD THEREFOR
Abstract	The preform is formed by an upper neck which maintains unchanged its form in the final object and a hollow body, joined to the neck. The method foresees the insertion, within a matrix cavity, of a metered body of polymeric material whose mass is metered according to a reference value, and the subsequent pressure insertion of a punch within the matrix cavity until it closes the mold's molding chamber, the punch conferring the shape to the inner surface of the preform and the matrix having an inner surface which confers the shape to the outer surface of the preform. According to the invention, in the molding of the preform, the error of the mass of the metered body with respect to the reference value is distributed in the hollow body, which undergoes a subsequent hot deformation until it achieves the final shape. In the mold, the matrix comprises at least one deformable wall (31) whose inner surface defines at least part of the inner surface of the matrix part intended to give form to the hollow body of the preform, said deformable wall (31) having, at least in part, a relatively thin thickness which permits it to be elastically deformed under the pressure of the polymeric material in the final preform molding step, thereby varying the thickness of the hollow body.

Title of Invention

METHOD OF MAKING CONCAVE OBJECTS IN POLYMERIC MATERIAL AND MOLD THEREFOR

Abstract

The preform is formed by an upper neck which maintains unchanged its form in the final object and a hollow body, joined to the neck. The method foresees the insertion, within a matrix cavity, of a metered body of polymeric material whose mass is metered according to a reference value, and the subsequent pressure insertion of a punch within the matrix cavity until it closes the mold's molding chamber, the punch conferring the shape to the inner surface of the preform and the matrix having an inner surface which confers the shape to the outer surface of the preform. According to the invention, in the molding of the preform, the error of the mass of the metered body with respect to the reference value is distributed in the hollow body, which undergoes a subsequent hot deformation until it achieves the final shape. In the mold, the matrix comprises at least one deformable wall (31) whose inner surface defines at least part of the inner surface of the matrix part intended to give form to the hollow body of the preform, said deformable wall (31) having, at least in part, a relatively thin thickness which permits it to be elastically deformed under the pressure of the polymeric material in the final preform molding step, thereby varying the thickness of the hollow body.

Full Text	WO 2006/040631 PCT/IB2005/002671 1 METHOD AND GROUP FOR THE COMPRESSION MOLDING OF PREFORMS FOR CONTAINERS IN POLYMERIC MATERIAL TECHNICAL FIELD 5 ThA present invention relates to the compression molding of (semi-finished) preforms intended for the subsequent realisation (typically through stretch blow molding) of concave objects, such as bottles, in polymeric material. The preform comprises an upper neck which maintains unchanged the shape of the final object and a hollow body, placed below the neck, which is instead dilated until 10 it assumes a much greater capacity and a correspondingly reduced thickness. PRIOR ART According to present technique, to form the preform it is first foreseen the insertion, within a rigid metal matrix (in steel) of a metered body of polymeric material whose mass is metered according to a pre-established value such to completely and exactly 15 fill the molding chamber of the mold, and, subsequently, the pressure insertion of a punch within the same matrix cavity until it closes the mold's molding chamber, i.e. the chamber which, when the mold is in closed position, remains between the punch and the inner surface of the matrix and defines the shape of the preform. The punch conferring the shape to the inner surface of the preform and the matrix having an 20 inner surface which confers the shape to the outer surface of the preform, A technical problem, present in the described technology and connected with said molds, arises from the fact that, in the metering of the body of polymeric material (metering) to be inserted into the matrix (typically through the separation of the body from a continuous and unshaped mass supplied by an extruder means), one inevitably 25 obtains (small) differences in value with respect to the pre-established value, while the volume of the (closed) chamber of the mold, which must be completely and exactly filled with polymeric material to form the preform, is instead constant for each mold; there exists therefore the technical problem of compensating the inexactness of the mass of the metered body with respect to the reference value. 30 To such end it has been proposed (see for example the publication JP 10-337769) to compensate the mass error (with respect to a reference value) by concentrating it in the zone of the neck of the preform through relative displacements between some WO 2006/040631 PCT/IB2005/002671 2 parts of the mold, in particular varying some dimensions of a flat collar normally present on the neck, having mainly the function of support of the bottle in some of the operations in which this is subjected. This solution, while having the merit of transferring the mass error into a formal 5 element which disturbs neither the functionality nor the external aspect of the bottle, presents nevertheless considerable disadvantages. Indeed, said transfer of the mass error of one part of the neck occurs while a mutual (if relatively small) movement takes place among the mold components and while at the same time a cooling of the material occurs. This involves the rising of inner tensions in the zone where the error 10 compensation takes place, which, when the neck subsequently undergoes mechanical stress, for example in the capping step of the bottle, may lead to the breaking or to unacceptable damage of the neck parts themselves. Moreover, for example, in the case in which, as the Japanese document foresees, said error transferring is localised in a zone where a circular groove is present on the 15 collar of the neck, it occurs that when the collar itself slides along appropriate transfer guides, such groove causes undesirable friction and moreover acts as a receptacle for dirt. STATEMENT OF THE INVENTION An object of the present invention is to solve said technical problem through a valid 20 and effective solution. Another object of the invention is to improve at the same time the thermal exchange between the mold and preform which takes place during the molding and the subsequent solidification of the preform itself, in order to render more rapid such solidification step. 25 Said and other objects are achieved by the invention herein as characterised in the claims. The method according to the invention foresees to distribute in the hollow body the mass error of the metered body with respect to the reference value, in the molding of the preform, being further foreseen that the hollow body undergoes a subsequent hot 30 deformation until it achieves the final shape. When the preform, after its molding, is subsequently cooled, it is possible that the fact of distributing the mass error of the metered body in the hollow body may WO 2006/040631 PCT/IB2005/002671 3 induce the rising of inner tensions. Nevertheless, since it is foreseen that the hollow body is subjected to a subsequent heating with hot deformation until it achieves the final shape, with such heating all of the possible inner tensions are more or less eliminated. The same is valid in the case in which the preform is not cooled but is 5 maintained at a sufficiently hot temperature, and is deformed until it achieves the final shape. According to a preferred embodiment, the compensation of the error of the metered body in the preform molding is realised with an elastic deformation of at least one part of the inner surface of the matrix. In such case the reference value of the mass of 10 the metered body is calculated so that, the error taken into account, the metered body has a mass such to always fill the volume in a complete manner, calculated "in unloaded condition" (i.e. in conditions of inactivity of the mold), of the mold's molding chamber and that the error proves to be an excess of polymeric material with respect to the volume of the chamber itself. In the subsequent molding step of 15 the preform, due in fact to the presence of said excess of polymeric material, at least part of the inner surface of the matrix is elastically deformed (to an extent which varies in relation to the size of the error) with respect to the shape that the same possesses "in unloaded condition", consequently increasing the thickness of the hollow body with respect to the thickness value "in unloaded condition", thereby 20 absorbing the error of the metering. The excess of polymeric material is thus distributed in a homogenous and regular manner in the hollow body of the preform, determining an error in its thickness of a quite modest value (on the order of several hundredths of a millimetre). When subsequently the preform, and in particular its hollow body, is subject to 25 deformation to achieve the foreseen final shape, said error of the thickness of the hollow body is distributed over a much greater surface and is thus further reduced. In practice, the initial error of the mass of the metered body becomes practically imperceptible in the final bottle, even difficult to perceive with traditional measuring instruments. 30 The part of the matrix which, as said above elastically deforms, is adapted to resist such deformation to the extent that the polymeric material achieves in the final molding step a pressure of value substantially equal to the pre-established design WO 2006/040631 PCT/IB2005/002671 4 value. BRIEF DESCRIPTION OF THE DRAWINGS Further details of the invention are set out below with the aid of the attached figures which illustrate, as an example, several embodiments of the mold for the molding of 5 the preform. FIG. 1 is an axial section of a first embodiment of the mold according to the invention. Fig. 1A shows the central part of Fig. 1, in enlarged scale. FIG. 1B is a perspective view of the deformable wall 31 of Fig. 1. 10 FIG. 1C is a different embodiment of the deformable wall 31 of Fig. 1A. Fig. 1D is an enlarged detail of Fig. 1. FIGS. 2A - 2D show the mold of FIG. 1 in a succession of steps during the molding of the preform. FIG. 3 is an axial section of a second embodiment of the mold according to the 15 invention. FIG. 4 is an axial section of a third embodiment of the mold according to the invention. Fig. 4A is the plan view from above of the bottom portion 39 of Fig. 4. Fig. 5 shows, in perspective view, an example of a preform obtained with the 20 invention. FIG. 6 is an axial section of a fourth embodiment of the mold according to the invention. DETAILED DESCRIPTION OF THE INVENTION An example of a preform which is desired to be obtained according to the invention 25 is illustrated in FIG. 5. This preform, indicated with 9, is for realising (typically through stretch blow molding) bottles in thermoplastic resin PET and comprises a neck 91, having the final shape foreseen in the bottle, and a hollow body 92 intended, in the realisation step of the bottle, to form the container body of the same. Generally, the neck 91 is provided with projections which define, for example, a 30 thread 93 projecting radially outward suited to receive a common screw cap. The hollow body 92 has on the other hand a continuous outer surface, generally nearly cylindrical (slightly tapered toward the bottom for delivery reasons) and terminating WO 2006/040631 PCT/IB2005/002671 5 in the lower end with a more or less spherical cap. In particular, the hollow body 92 comprises a side wall 92a, typically substantially cylindrical, and a bottom wall 92b, typically in the form of a cap. The preform 9 is obtained with a process of compression molding through the 5 pressure insertion of a punch 11 (male element of the mold) within a closed-cavity hollow matrix (female part of the mold), loaded with a metered body 8 of polymeric material (in particular a thermoplastic resin) at the more or less viscous pasty state, whose mass is metered according to a reference value. The molding machine which utilises the mold according to the invention is typically 10 but not exclusively of the continuously rotating turntable type, and typically but not exclusively operates with a plurality of equal molding groups which are operated in sequence. Illustrated in the figures is only a generic meld according to the invention. The machine on the other hand is not illustrated, being per se of traditional type. 15 The mold according to the invention comprises a matrix and a punch 11. Together, punch 11 and matrix cavity give rise to a molding chamber 7 which confers the desired shape to the preform 9. The cavity of the matrix confers shape to the outer surface of the preform while the outer surface of the punch 11 confers shape to the inner surface of the preform 9. 20 According to the embodiment illustrated in the figures, the matrix of the mold is formed by: an upper matrix part 20 having inner surface 21 adapted to form the outer surface of the upper neck 91 of the preform, divided into at least two sectors adapted to be distanced between each other to permit the extraction of the preform 9, 25 a lower matrix part 30 having inner surface adapted to form the outer surface of the hollow body 92 of the preform. The two upper 20 and lower 30 matrix parts may be separated from each other in the loading step of the metered body 8, which is inserted in the cavity of the only lower matrix part 30; the inner surface areas of said upper 20 and lower 30 matrix parts are 30 adapted, when they are operatively associated to each other, to form the entire cavity of the matrix. Alternatively, the two matrices are maintained associated to each other also in the WO 2006/040631 PCT/IB2005/002671 6 loading step of the metered body. According to the invention, the lower matrix part 30 comprises an undeformable support body 40 which houses at its interior at least one deformable wall 31 realised in steel (or in an equivalent material) whose inner surface defines at least a part of 5 the inner surface of the lower matrix part, having at least a portion in the shape of foil having a relatively thin thickness which permits it to be elastically deformed under the pressure of the polymeric material in the final molding step of the preform so to vary, in particular to increase, the thickness of the hollow body. The deformation of the wall 31 occurs mainly by bending the section along the generic 10 axial plane, together with deformations by traction, while the thickness of the wall does not undergo considerable variations. According to the first embodiment, illustrated in Fig. 1, the lower matrix part 30 comprises a portion 38 having tubular form, in particular substantially cylindrical, which defines said deformable wall 31, whose inner surface 31' confers the shape, at 15 least in part (and in particular, as illustrated, almost completely) of the outer surface of the side wall 92a of the hollow body 92, which wall 31 has a relatively thin thickness which permits it to be elastically deformed under the pressure of the polymeric material. The deformable wall 31 is housed, in particular it is enclosed, within a coaxial cavity 20 36 made in the support body 40; whose inner surface is placed a distance from the outer surface of the wall 31, such that this may be radially deformed without being hindered by the body 40 itself. The deformable wall 31 comprises an enlarged section which defines a circular band 32 near the upper end and a second enlarged section, near the lower end, which 25 defines a second circular band 33. Said circular bands 32 and 33 have respective outer cylindrical surfaces 32' and 33' which abut corresponding seats 34 and 35 made in the coaxial cavity 36 of the support body 40; thus defined are two circular radial abutting zones for the wall 31 which also serve for the centring of the wall 31. Said surfaces 32' and 33' are perfectly cylindrical so that the abutting operates only 30 in the radial direction. The upper band 32 also has a shoulder 32a which is blocked in the axial direction by the seat 34. Along the generic section in the axial plane, the deformable wall 31 comprises, from WO 2006/040631 PCT/IB2005/002671 7 one side and from the other with respect to the axis, two end portions defined by the circular bands 32 and 33, which form abutments which hinder radial displacement and a central portion, laminar and having a relatively thin thickness compared with the axial length in a single body with the two end portions, free to elastically bend in 5 the radial direction, forming an arch in the axial plane. In detail, the support body 40 comprises a first tubular body 41 and a second, upper body 42 bound together with the first in monolithic manner by an outer envelope 43 and by an upper closing element 44 associated to the envelope 43. The cavity 36 is made nearly entirely in the lower body 41. !0 Inside the first body 41 an undeformable central body 45 is placed whose upper surface 45' defines the outer surface of the bottom wall 92b of the hollow body 92. The lower band 33 is also blocked in the axial direction by the respective seat 35. More precisely, a lower shoulder is foreseen near the lower end of the inner wall 31 which comes into contact with the upper end edge of the central body 45 in order to 15 ensure the continuity between the inner surface 31' of the wall 31 and the upper surface 45' of the central body 45. The cavity 36 is connected, through conduits 46 and others (not illustrated), with means adapted to introduce, circulate and discharge refrigerant fluids capable of removing heat from the preform in a thermal conditioning step (cooling) of the same. 20 The deformable wall 31 lends itself in a particular manner to this end due to the fact that it possesses a relatively thin thickness, which greatly favours the transmission of heat through it. Moreover, the deformable wall 31 may have different reliefs 37 placed along the outer surface, which define the elements of thermal exchange; these elements are 25 interrupted in the circumferential direction in order not to hinder the elastic radial dilation of the deformable wall 31 in the molding step. In the embodiment illustrated in Fig. 1A e IB, the reliefs 37 have the shape of fins which project radially and which extend for a distance in the axial direction; these reliefs are moreover placed alternately between one line and the other in order to 30 realise maximum turbulence in the passage of the refrigerant fluid and therefore maximise the thermal exchange with the wall 31. In the embodiment illustrated in Fig. 1C the reliefs 37 have the shape of rings placed WO 2006/040631 PCT/IB2005/002671 8 on planes transverse to the axis of the wall 31 and nevertheless interrupted in order to not realise stiffening ribs which may hinder the radial dilation of the wall 31. There may be foreseen, moreover, appropriate ducts (not shown in the figures) adapted to cool and/or thermoregulate the central body 45 so to cool and/or 5 thermoregulate through such body the lower end portion of the preform. The punch 11 is integrally fixed to an upper body 10 with which it forms a single body and of which it defines the lower end portion, that which confers shape to the inner surface of the preform. In detail, the upper body 10 comprises a shoulder adapted to abut against the upper end 23 of the upper matrix part 20, and a lower 10 portion 10" which in its lower section is united to the punch 11 itself. The upper surface 91b of the upper end edge of the neck 91 of the preform 9 is formed in part by a narrow, downward-turned upper surface 21b, which terminates with a substantially horizontal tengent which defines the upper border of the inner surface 21 of the upper matrix part 20, and in part is formed by a narrow upper 15 surface 12b, downward-turned and terminating with a substantially horizontal tangent, which defines the upper border of the outer surface of the punch 11, at the border with the lower end of the lower portion 10" of the upper body 10 (see Fig. ID). When the two said upper surfaces 12b and 21b are aligned with each other, the mold 20 is then in closed position, i.e. the punch 11 and the matrix parts 20 and 30 are mutually coupled such that the mold cavity defines the molding chamber 7 in which, between the inner surface of the matrix parts 20 and 30 and the surface of the punch 11, lies defined the shape of the preform. In operation, it is first foreseen (Fig. 2A) to insert in the cavity of the matrix a 25 metered body 8 of polymeric material, whose mass is metered according to a reference value which is established such that, taken into account the error which inevitably exists in the metering of such body, the body 8 itself always fills in a complete manner the volume of the molding chamber 7 of the mold calculated "in unloaded condition" and that the error proves to be an excess of polymeric material 30 with respect to the volume of the chamber itself. Subsequently, the mutual approaching among the mold components is carried out, for example, following a lifting of the lower matrix part 30, operated through a lower WO 2006/040631 PCT/IB2005/002671 9 device (not shown in the figures) while the upper body 10, which bears the punch 11, and the punch itself on the other hand remain still. In the figures from 2A to 2D a horizontal reference axis is indicated with an X, which remains fixed, passing tlvrough the lower abutting shoulder of the upper 5 portion 10' of the body 10. It is nevertheless obvious that that of importance here is the movement related to the mutual approaching; this may be obtained, alternatively, following a downward movement of the upper body 10, possibly together with an upward movement of the lower device which bears the matrix. 10 First, (Fig. 2B) the punch 11 begins to penetrate into the cavity of the lower matrix part 30, beginning to progressively deform the metering 8. Subsequently, the upper end of the lower matrix part 30 comes to couple with the lower end of the upper matrix part 20 (position illustrated in Fig. 2C) and the punch 11 continues to penetrate in the cavity of the matrix, continuing to deform the 15 metering 8. The sectors which form the upper matrix part 20 are locked in radially closed position through an upper annular body 14 (of known type) associated to the punch 11 and vertically moving with respect to it, whose lower end portion possesses a concave frustoconical surface 14a, which mates with a complementary outer and upper side surface 26 of the upper matrix part 20, it too of frustoconical shape. 20 Subsequently, the punch 11 continues to penetrate (always following upward displacements of the lower device which bears the matrix) within the matrix cavity until it produces the complete closing of the mold, which occurs when the two surfaces 12b and 21b are in contact with each other (position shown in Fig, 2D). At this point the penetration of the punch terminates. 25 During this final molding step of the preform, it occurs that first, when the molding chamber 7 is still not closed, the polymeric material of the metering completely fills such chamber 7, while the deformable wall 31 is not yet deformed, at least in appreciable terms, achieving appropriately high pressure values, in the range of the design values foreseen at the end of the molding. Then, the penetration of the punch 30 continuing further into the matrix cavity until the closing of the mold, since the polymeric material has an excess volume with respect to the volume of the chamber 7, such material, pushed by the pressure produced by the penetration of the punch, WO 2006/040631 PCT/IB2005/002671 10 causes the elastic wall 31, whose generic axial section is free to bend, not having any constraint other than the abutments provided by the bands 32 and 33, to be elastically deformed with outward radial displacement until said excess volume is absorbed. 5 The elastic deformation which the deformable wall 31 undergoes is of bending type in the section along a generic axial plane, with displacement of the axially middle zone of the wall itself which bends outward, said displacement being as great as said excess volume of the metering. On the other hand, along the generic transverse plane, the deformation which the elastic wall 31 undergoes, in tubular form 10 according to the first embodiment (fig. 1A), consists of an increase in the diameter of the tubular wall itself which achieves maximum value in the axially middle zone. The tubular wall 31 is therefore subject to stress composed of elastic bending and traction together. The described deformation of the wall 31 illustrated in figures I and 1A, produces a distributed and regular increase of the thickness of the side wall 15 92a of the hollow body 92 which achieves maximum value in the intermediate zone thereof, while such thickness remains nearly unchanged at the bands 32 and 33 since these are scarcely deformable. The elastic deformation does not even involve other parts of the matrix, and in particular the upper part 20 which gives shape to the neck 91, which remain instead 20 unaltered. The error of the mass of the metering with respect to the reference value is therefore distributed in the preform part placed at the deformable wall 31 and hence in the hollow body 92. The reference value of the mass of the metering 8 is calculated so that taking into 25 account both the error in the formation of the metering 8 and the volumetric shrinkage which occurs in the cooling of the preform during the molding, the complete filling of the molding chamber 7 is realised and moreover such that the polymeric mass is subjected, in the final step of the molding, to a pressure having appropriate design values (on the order of several hundred bar). In particular, it may 30 be foreseen that said reference value is such that the polymeric material of the metering has always a greater volume than the volume of the molding chamber and that therefore the deformable wall 7 always undergoes a deformation, of a more or WO 2006/040631 PCT/IB2005/002671 11 less significant measure. For its own part the deformable wall 31 is designed with structural characteristics (in particular the material and the thickness in relation with the length) such that it can be elastically deformed so to absorb the excess volume of the metering and provide 5 at the same time, in virtue of only its own structural characteristics (without the intervention of outside means or actions), a sufficient resistance to elastic deformation to allow that the polymeric material of the metering achieves in the final molding step said design values regarding the pressure, where moreover the deformation of the wall 31 takes place following the complete filling of the molding 10 chamber. Therefore, the deformable wall 31 shall be sized in relation with several parameters including the force of the molding in play and the size of the errors of the metering. For example, for a preform having a mass of 24 grams, and having a totai axiai length of 100 mm, it was utilised, in the lower matrix part 30, a deformable wall 31 15 in stainless steel, with low values of carbon and high values of Mo, Ni, Co and Ti, whose thickness in the central part comprised between two abutments defined by the bands 32 and 33 is approximately 2.5 mm. In the test operation, foreseeing for the mass of the metered body 8 a maximum error of 1 %, radial deformations were detected in the wall 31 on the order of 0.02-0.05 mm. 20 In the second embodiment, illustrated in Fig. 3, the deformable wall 31 comprises a side portion 38 having tubular form (substantially equal to the whole wall 31 of the first embodiment) in particular substantially cylindrical, whose inner surface 38' defines at least in part (and in particular, as illustrated, nearly completely) the outer surface of the side wall 92a of the hollow body 92, and also a bottom portion 39, in 25 the shape of a cap joined in a single body to the side portion 38, whose inner surface 39' defines the outer surface of the bottom wall 92b of the hollow body 92. This deformable wall 31 has nearly entirely a relatively thin thickness which permits it to be elastically deformed, under the pressure of the polymeric material, both in the side portion 38 and in the bottom portion 39. 30 The two said circular bands 32 and 33 are present, placed at the respective upper and lower ends of the side portion 38. The coaxial cavity 36, in this case, also wraps around the bottom portion 39 of the WO 2006/040631 PCT/IB2005/002671 12 wall 31. Said lower seat 35, on which abuts the lower band 33, defines a cylindrical abutment surface and is made on a limited number of radial and axial fins 48 which permit the communication between the lower and upper part of the cavity 36. 5 The abutment between the band 33 and the respective abutment seat 35 permits the axial sliding of the band itself, so to not hinder the axial elastic deformation of the deformable wall 31. Therefore, also in this second embodiment, as in the first, the deformable wall 31 comprises a deformable tubular portion 38 which has, along the generic axial section, 10 from one side and the other with respect to the axis, two end portions defined by the circular bands 32 and 33, which form abutments which hinder the radial displacement, and a central portion, laminar and having a relatively thin thickness in relation with the axial length, in a single body with the two end portions, free to elastically bend in radial direction, forming an arch in the axial plane. Moreover it 15 also comprises a deformable bottom portion 39 which has, along generic axial section, two end portions, both defined by the circular band 33, and a central portion, having a relatively thin thickness in relation with the length, free to elastically bend in the axial direction. The cavity 36 is connected, through a lower mouth 49 made in the central body 45b 20 and other not-illustrated conduits, with means adapted to circulate refrigerant fluids capable of removing heat from the preform in a step of thermal conditioning (cooling) of the same. In operation, this embodiment differs from the preceding for the fact that the pressure exerted by the metering 8 on the inner surface of the molding chamber 7 causes an 25 elastic deformation both of the side portion 38 and the bottom portion 39 of the deformable wall 31 and therefore the error of the metering is apportioned also to the bottom portion 92b, in addition to the side portion 92a of the hollow body 92. Moreover, the deformable wall 31 is subject to both bending and axial elongation deformations. 30 Also in the third embodiment, illustrated in Fig. 4, as in the second, the deformable wall 31 comprises a side portion 38 having tubular form (substantially equal to the whole wall 31 of the first embodiment) in particular substantially cylindrical, whose WO 2006/040631 PCT/IB2005/002671 13 inner surface 38' defines at least in part (and in particular, as illustrated, almost completely) the outer surface of the side wall 92a of the hollow body 92, and also a bottom portion 39, in the shape of a cap joined to the side portion 38, whose inner surface 39' defines the outer surface of the bottom wall 92b of the hollow body 92. 5 Nevertheless, unlike the second embodiment, this foresees that the two portions 38 and 39 are separated from each other and in any case associated to form a continuity of the respective inner surfaces. Said lower circular band 33 is made in the upper circular border of the bottom portion 39 and in correspondence thereof the two portions 38 and 39 are mutually 10 fixed. The band 33 has a series of radial-axial ribs 51 whose free radial ends define a cylindrical surface which abuts against the lower seat 35, it too cylindrical. Here too, as in the preceding embodiment, the coaxial cavity 36 also wraps around the bottom portion 39 of the wall 31 and the lower seat 35, and the ribs 51 permit the communication between the lower part of the cavity 36 and the upper part thereof. 15 In particular, inside the tubular body 41 there is a central body 45b whose upper surface is placed a distance from the lower surface of the bottom portion 39. The abutment between the band 33 and the respective abutment seat 35 permits the axial sliding of the band itself, so to not hinder the axial elastic deformation of the deformable wall 31. 20 The cavity 36 is connected, through a lower mouth 52 made in the central body 45b and other not-illustrated conduits, with means adapted to circulate refrigerant fluids in the cavity 36 itself capable of removing heat from the preform in a step of thermal conditioning (cooling) of the same. In the lower part of the cavity 36, below the abutment ribs 51, there are several fins 53 projecting upward from the central body 25 45b, adapted to better direct the flux of the refrigerant fluid, and which do not hinder the deformation of the wall 31 with which they do not come into contact. Also in this third embodiment, the error of the metering is apportioned also to the bottom portion 92b, in addition to the side portion 92a of the hollow body 92. There may moreover be foreseen several conduits 54, made in the support body 40, 30 in particular in the central body 45b and in the fins 53, which cross the ribs 51 and the lower band 33, which lead in correspondence with the surfaces of mutual connection between the lower end of the side portion 38 and the upper end of the WO 2006/040631 PCT/IB2005/002671 14 bottom portion 39. Said conduits 54 may be advantageously connected with suction means in order to clear the air present in the cavity of the mold before and during the compression step of the metering. 5 Moreover, or alternatively, the conduits 54 may be advantageously connected with means adapted to inject air or another thermally conditioned fluid inside the cavity, before the opening step of the mold, to favour the cooling and the detachment of the preform after its molding. The fourth embodiment (Fig. 6) consists of a variation of the first embodiment 10 (figure 1 and 1A) in which the central body 45 was modified according to the teaching of the invention described in the patent application n. PCT/IB2005/002303 (claiming the priority of the Italian patent application n.RE2004A000127 of the same Applicant), mainiy in order to increase the capacity of the matrix to receive the metering. In particular, the central body 45 is realised so to comprise a first 15 component body 451 and a second component body 452, situated centrally with regards to the first, having respectively inner surfaces 453 and 454 which may be aligned in a complementary manner to define, together, the inner surface 45'. The first component body 451 is integrally fixed to the remaining lower matrix part, in particular it is integrally fixed to the body 41. The second component body 452 is 20 movable with respect to the first component body 451 between an upper position (illustrated with a continuous line in Fig. 6) in which its inner surface 454 is placed in aligned or nearly aligned position with the inner surface 453 of the first component body 451 and a back position (illustrated with a dashed line in Fig. 6) in which its inner surface 454 is placed a distance from the inner surface of the first 25 component body in order to increase the volume of the cavity of the lower part of the matrix. Finally, operation means are foreseen (not illustrated in the figures) adapted to arrange said second component body in said back position in the loading step of a metering of polymeric material in the cavity of the lower matrix part 30 and to bring it to the upper position in the molding step. 30 In operation, first a metering is formed outside of the mold and then inserted in the cavity of the lower matrix part, while the second component body 452 is in said back position. WO 2006/040631 PCT/IB2005/002671 15 Subsequently, the progressive insertion of the punch in the matrix cavity is carried out until the closing of the mold, with modalities equal or similar to those described above with reference to the figures 2A to 2D, while the second component body 452 is maintained in said back position. 5 Once the complete penetration of the punch 11 in the matrix cavity is realised until the closing of the mold (in which the lower matrix part 30 is coupled with the upper part 20 and the two surfaces 12b and 21b are in mutual contact), the upward displacement is produced of the second component body 452 until it reaches the upper position. This final step may begin after the closing of the mold, or a little 10 before. In this last step, the polymeric material is pushed to completely fill the molding chamber and then to deform the elastic wall 31, thereby increasing the thickness of the hollow body, until the excess volume of the metering is absorbed. The upper position does not necessarily coincide with the position in which the 15 surface 454 of the second component body 452 represents the exact geometric continuation of the surface 453 of the other component body 451 ("nominal position" of design) but is separated from this in a variable manner, in relation with a level of error of the mass of the metering. This upper position may therefore result below said "nominal position". 20 According to a further embodiment (not shown in the figures) it is foreseen that said deformable inner wall 31 comprises only the bottom portion and that therefore the error of the metering is apportioned only to the bottom portion 92b of the hollow body 92. According to the invention, the preform, after its molding, is cooled and 25 subsequently subjected to a process of deformation through stretch blow molding in which the hollow body is newly heated, until the desired shape of the container is achieved. Alternatively, the preform is subjected to the process of deformation through stretch blow molding v/hile the temperature of its hollow body is still sufficiently hot. 30 Thanks to the invention, firstly, the error of the mass of the metering is distributed in a continuous manner and over a relatively quite wide surface such that no trace is left in the exterior aspect of the final containers which are obtained at the end of the WO 2006/040631 PCT/IB2005/002671 16 entire process; nor is it possible to perceive, in practice, size variations between one final container and the other. Moreover, after the molding of the preform, the possible further tensions which form in the distribution of the error of the metered body in the hollow body are eliminated 5 with the hollow body's subsequent heating; or else such tensions do not even form since the temperature of the hollow body is maintained sufficiently high and the mass is maintained in a more or less viscous fluid state. The fourth embodiment (Fig. 6) increases the volume of the cavity of the lower matrix part, with respect to that of a traditional mold, in the step in which it receives 10 the metering, and thus renders such cavity capable of receiving metered bodies having higher mass and/or height than would otherwise be receivable. Moreover, it renders possible the compensation of relatively greater mass errors, thanks to the fact that to the compensation which is obtained through the elastic deformation of the elastic wall 31 a compensation may be added, obtained by ensuring that the upper 15 position of the component body 452 does not exactly coincide with said "nominal position", but is separated from this to compensate for at least a part of the metering error. 22-12-2006 IB20050026 27182 REPLACEMENT PAGE 17 CLAIMS 1. Method for making concave objects in polymeric material, comprising: - compression molding of preforms comprising an upper neck which maintains 5 the same form of the final concave object and a hollow body, joined to the neck, and -the subsequent deformation treatment of the hollow body under hot temperature wherein it is dilated to assume a greater capacity and a correspondingly reduced thickness; 10 the compression molding of preforms comprising: - providing a mould having a matrix comprising a first part (20) to form the outer surface of the upper neck (91) and a second matrix part (30) to form the outer surface of the hollow body (92), and a punch to form the inner surface of the preform, the second matrix part (30) comprising a defcrrnable wa!! (31); 15 - inserting a metered mass body of polymeric material within a matrix cavity, the reference mass value of the metered body being calculated such that an error results as an excess mass of polymeric material, and - pressure inserting the punch into the matrix cavity with progressive movement relatively to it until the mold is in a closed position and the polymeric material 20 completely fills the mould molding chamber in the insertion final step, wherein the punch insertion causes the elastic deformation of said deformable wall (31) to adsorb the error of the metered mass body, the excess mass being distributed along the whole perimeter of the hollow body transversal section to increase its thickness. 25 2. Method according to claim 1, characterised in that after the molding of the preform, the hollow body is subject to a cooling and to a subsequent heating and deformation treatment until it achieves the final shape. 30 3. Method according to claim 1, characterised in that, in the molding of the preform, a side portion (38) of the elastic wall (31) having tubular form ), is elastically deformed to distribute the excess of the metered mass body, at least in part, in the side wall (92a) of the hollow body (92). 35 4. Method according to claim 3, characterised in that in said final step of the punch penetration, the polymeric material of the metered body completely fills the molding chamber (7) and the volume of the excess polymeric material. AMENDED SHEET 22-12-2006 IB20050026' 27182 REPLACEMENT PAGE 18 pushed by the penetration of the punch, causes the the pressure value of the polymeric material to reach a value substantially equal to a pre-established value in virtue of the resistance to elastic deformation produced by deformable wall (31) without the intervention of external means or actions. 5 5. Method according to claim 3, characterised in that in the molding of the preform at least part of the inner surface of the matrix is elastically deformed with respect to its position "in unloaded condition", such in a way to increase the length of the hollow body so to absorb the excess of polymeric material. 10 6. Preform in polymeric material intended for the molding of concave objects, formed through the method of claim 1. 7. Mold for the compression molding of preforms in polymsric material 15 intended for the molding of concave objects, the preform comprising an upper neck which maintains the same form in the final object and a hollow body joined to the neck, wherein the compression molding process comprises the insertion of a mass body of polymeric material, metered with an excess error, into the mold and the 20 pressure insertion of the punch within the matrix cavity with progressive movement relatively to it, until the mold is in a closed position and the polymeric material completely fills the mould molding chamber in the insertion final step, the mold comprising: a matrix having a part (20) to form the outer surface of the upper neck (91) and 25 another matrix part (30) to form the outer surface of the hollow body (92), and a punch for forming the inner surface of the preform; the matrix comprising at least one deformable wall (31) whose inner surface defines at least a part of the inner surface of the matrix part to form the hollow body (92) of the preform, said deformable wall (31) having, at least in part, a 30 relatively thin thickness characterised in that said deformable wall (31) is elastically deformable, under the pressure of the polymeric material produced by said punch insertion, such in a way to increase the thickness of the hollow body to adsorb the excess error, and its structural characteristics1 are able to provide the whole resistance to said 35 elastic deformation without intervention of external means or actions. AMFNHFn SHFFT 22-12-2006 IB20050026"; 27182 REPLACEMENT PAGE 19 8. Mold according to claim 7, characterised in that the structural characteristics of the deformable wall (31) are able to provide resistance to said elastic deformation without the intervention of external means or actions, so that the polymeric material achieves a pressure value substantially equal to a project 5 pressure value in said punch insertion final step. 9. Mold according to claim 7, characterised in that said deformable wall (31) is realised in steel or equivalent material. 10 10. Mold according to claim 7, characterised in that said deformable wall (31), comprises a side portion (38) having tubular form whose inner surface (38') defines at least in part the outer surface of the side wall (92a) of the hollow body (92). 15 11. Mold according to claim 9, characterised in that the deformable wall (31) has at least one end portion (33) sliding on respective abutment seat (35) so to not hinder the axial component of the elastic deformation of the deformable wall (31). 20 12. Mold according to claim 10, characterised in that the deformable wall (31) comprises at least a portion (38) having, in the section along the generic axial plane, two end portions having abutments which prevent the displacements in the radial direction and a central portion, free to elastically bend in the radial direction. 25 13. Mold according to claim 10, characterised in that it comprises a central body (45) whose surface (45') defines the outer surface of the bottom wall of the preform, said central body 45 comprising a first fixed component body (451) and a second movable component body (452), having inner surfaces (453, 454) 30 which may be aligned in complementary manner to define, together, the inner surface (45'), said second component body 452 being movable with respect to the first component body (451) between an upper position in which its inner surface (454) is placed in aligned or nearly aligned position with the inner surface (453) of the first component body (451) and a back position in which its 35 inner surface (454) is placed a distance from the inner surface of the first component body so to increase the volume of the cavity of the lower part of the matrix, AMENDED SHEET 22-12-2006 IB20050026: 27182 REPLACEMENT PAGE 20 there being foreseen in addition operation means adapted to arrange said second component body (452) in said back position in the loading step of a metering of polymeric material in the cavity of the lower matrix part (30) and to bring it to the upper position in the molding step. 5 14. Mold according to claim 10, characterised in that the deformable wall (31) comprises a bottom portion (39) whose inner surface (391) defines, at least in part, the outer surface of the bottom wall (92b) of the hollow body (92). 10 15. Mold according to claim 10, characterised in that said deformable wall (31) has a circular band (32) at the upper end and a second circular band (33) at the lower end, said circular bands (32, 33) providing zones of radial abutment for the deformable wall (31). 15 16. Mold according to claim 15, characterised in that the abutment between the lower band (33) and the respective abutment seat (35) permits the axial sliding of the band itself, so to not hinder the axial component of the elastic deformation of the deformable wall (31). 20 17. Mold according to claim 10, characterised in that the deformable wall (31) is enclosed within a coaxial cavity (36) made in the support body (40) whose inner surface is placed a distance from the outer surface of the wall (31), so that this may be deformed without being hindered by the support body (40) itself. 25 18. Mold according to claim 10, characterised in that said deformable wall (31) has reliefs (37) placed on the outer surface which define elements of thermal exchange, interrupted along the circumferential direction in order to not hinder the elastic deformation of the deformable wall (31). 30 19. Mold according to claim 18, characterised in that the reliefs (37) are shaped as fins which project radially and extend for a distance in the axial direction, said reliefs (37) being moreover placed in alternate manner between one line and the next in order to realise the maximum turbulence in the passage 35 of the refrigerant fluid. 20. Mold according to claim 10, characterised in that the deformable wall AMENDED SHEET 22-12-2006 IB20050026' 27182 REPLACEMENT PAGE 21 (31) comprises a side portion (38) and a bottom portion (39) which are separated from each other and in any case associated to form continuity of their respective inner surfaces. 5 21. Mold according to claim 20, characterised in that it comprises at least one conduit (54), which leads in correspondence with the surfaces of mutual connection between the lower end of the side portion (38) and the upper end of the bottom portion (39), said conduit (54) being connected with suction means adapted to clear the air present in the cavity of the mold before and during the 10 compression step of the metering. 22. Mold according to claim 20, characterised in that it comprises at least one conduit (54), which across the deformable wall (31) leads in correspondence with the surfaces of mutual connection between the lower end of the side portion 15 (38) and the upper end of the bottom portion (39), said conduit (54) being connected with means adapted to inject air or other thermally conditioned fluid inside the cavity, before the opening step of the mold, to favour the cooling and the detachment of the preform. AMENDED SHEET The preform is formed by an upper neck which maintains unchanged its form in the final object and a hollow body, joined to the neck. The method foresees the insertion, within a matrix cavity, of a metered body of polymeric material whose mass is metered according to a reference value, and the subsequent pressure insertion of a punch within the matrix cavity until it closes the mold's molding chamber, the punch conferring the shape to the inner surface of the preform and the matrix having an inner surface which confers the shape to the outer surface of the preform. According to the invention, in the molding of the preform, the error of the mass of the metered body with respect to the reference value is distributed in the hollow body, which undergoes a subsequent hot deformation until it achieves the final shape. In the mold, the matrix comprises at least one deformable wall (31) whose inner surface defines at least part of the inner surface of the matrix part intended to give form to the hollow body of the preform, said deformable wall (31) having, at least in part, a relatively thin thickness which permits it to be elastically deformed under the pressure of the polymeric material in the final preform molding step, thereby varying the thickness of the hollow body.

Full Text

WO 2006/040631 PCT/IB2005/002671
1
METHOD AND GROUP FOR THE COMPRESSION MOLDING OF PREFORMS
FOR CONTAINERS IN POLYMERIC MATERIAL
TECHNICAL FIELD
5 ThA present invention relates to the compression molding of (semi-finished)
preforms intended for the subsequent realisation (typically through stretch blow
molding) of concave objects, such as bottles, in polymeric material.
The preform comprises an upper neck which maintains unchanged the shape of the
final object and a hollow body, placed below the neck, which is instead dilated until
10 it assumes a much greater capacity and a correspondingly reduced thickness.
PRIOR ART
According to present technique, to form the preform it is first foreseen the insertion,
within a rigid metal matrix (in steel) of a metered body of polymeric material whose
mass is metered according to a pre-established value such to completely and exactly
15 fill the molding chamber of the mold, and, subsequently, the pressure insertion of a
punch within the same matrix cavity until it closes the mold's molding chamber, i.e.
the chamber which, when the mold is in closed position, remains between the punch
and the inner surface of the matrix and defines the shape of the preform. The punch
conferring the shape to the inner surface of the preform and the matrix having an
20 inner surface which confers the shape to the outer surface of the preform,
A technical problem, present in the described technology and connected with said
molds, arises from the fact that, in the metering of the body of polymeric material
(metering) to be inserted into the matrix (typically through the separation of the body
from a continuous and unshaped mass supplied by an extruder means), one inevitably
25 obtains (small) differences in value with respect to the pre-established value, while
the volume of the (closed) chamber of the mold, which must be completely and
exactly filled with polymeric material to form the preform, is instead constant for
each mold; there exists therefore the technical problem of compensating the
inexactness of the mass of the metered body with respect to the reference value.
30 To such end it has been proposed (see for example the publication JP 10-337769) to
compensate the mass error (with respect to a reference value) by concentrating it in
the zone of the neck of the preform through relative displacements between some

WO 2006/040631 PCT/IB2005/002671
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parts of the mold, in particular varying some dimensions of a flat collar normally
present on the neck, having mainly the function of support of the bottle in some of
the operations in which this is subjected.
This solution, while having the merit of transferring the mass error into a formal
5 element which disturbs neither the functionality nor the external aspect of the bottle,
presents nevertheless considerable disadvantages. Indeed, said transfer of the mass
error of one part of the neck occurs while a mutual (if relatively small) movement
takes place among the mold components and while at the same time a cooling of the
material occurs. This involves the rising of inner tensions in the zone where the error
10 compensation takes place, which, when the neck subsequently undergoes mechanical
stress, for example in the capping step of the bottle, may lead to the breaking or to
unacceptable damage of the neck parts themselves.
Moreover, for example, in the case in which, as the Japanese document foresees, said
error transferring is localised in a zone where a circular groove is present on the
15 collar of the neck, it occurs that when the collar itself slides along appropriate
transfer guides, such groove causes undesirable friction and moreover acts as a
receptacle for dirt.
STATEMENT OF THE INVENTION
An object of the present invention is to solve said technical problem through a valid
20 and effective solution.
Another object of the invention is to improve at the same time the thermal exchange
between the mold and preform which takes place during the molding and the
subsequent solidification of the preform itself, in order to render more rapid such
solidification step.
25 Said and other objects are achieved by the invention herein as characterised in the
claims.
The method according to the invention foresees to distribute in the hollow body the
mass error of the metered body with respect to the reference value, in the molding of
the preform, being further foreseen that the hollow body undergoes a subsequent hot
30 deformation until it achieves the final shape.
When the preform, after its molding, is subsequently cooled, it is possible that the
fact of distributing the mass error of the metered body in the hollow body may

WO 2006/040631 PCT/IB2005/002671
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induce the rising of inner tensions. Nevertheless, since it is foreseen that the hollow
body is subjected to a subsequent heating with hot deformation until it achieves the
final shape, with such heating all of the possible inner tensions are more or less
eliminated. The same is valid in the case in which the preform is not cooled but is
5 maintained at a sufficiently hot temperature, and is deformed until it achieves the
final shape.
According to a preferred embodiment, the compensation of the error of the metered
body in the preform molding is realised with an elastic deformation of at least one
part of the inner surface of the matrix. In such case the reference value of the mass of
10 the metered body is calculated so that, the error taken into account, the metered body
has a mass such to always fill the volume in a complete manner, calculated "in
unloaded condition" (i.e. in conditions of inactivity of the mold), of the mold's
molding chamber and that the error proves to be an excess of polymeric material
with respect to the volume of the chamber itself. In the subsequent molding step of
15 the preform, due in fact to the presence of said excess of polymeric material, at least
part of the inner surface of the matrix is elastically deformed (to an extent which
varies in relation to the size of the error) with respect to the shape that the same
possesses "in unloaded condition", consequently increasing the thickness of the
hollow body with respect to the thickness value "in unloaded condition", thereby
20 absorbing the error of the metering.
The excess of polymeric material is thus distributed in a homogenous and regular
manner in the hollow body of the preform, determining an error in its thickness of a
quite modest value (on the order of several hundredths of a millimetre).
When subsequently the preform, and in particular its hollow body, is subject to
25 deformation to achieve the foreseen final shape, said error of the thickness of the
hollow body is distributed over a much greater surface and is thus further reduced. In
practice, the initial error of the mass of the metered body becomes practically
imperceptible in the final bottle, even difficult to perceive with traditional measuring
instruments.
30 The part of the matrix which, as said above elastically deforms, is adapted to resist
such deformation to the extent that the polymeric material achieves in the final
molding step a pressure of value substantially equal to the pre-established design

WO 2006/040631 PCT/IB2005/002671
4
value.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the invention are set out below with the aid of the attached figures
which illustrate, as an example, several embodiments of the mold for the molding of
5 the preform.
FIG. 1 is an axial section of a first embodiment of the mold according to the
invention.
Fig. 1A shows the central part of Fig. 1, in enlarged scale.
FIG. 1B is a perspective view of the deformable wall 31 of Fig. 1.
10 FIG. 1C is a different embodiment of the deformable wall 31 of Fig. 1A.
Fig. 1D is an enlarged detail of Fig. 1.
FIGS. 2A - 2D show the mold of FIG. 1 in a succession of steps during the molding
of the preform.
FIG. 3 is an axial section of a second embodiment of the mold according to the
15 invention.
FIG. 4 is an axial section of a third embodiment of the mold according to the
invention.
Fig. 4A is the plan view from above of the bottom portion 39 of Fig. 4.
Fig. 5 shows, in perspective view, an example of a preform obtained with the
20 invention.
FIG. 6 is an axial section of a fourth embodiment of the mold according to the
invention.
DETAILED DESCRIPTION OF THE INVENTION
An example of a preform which is desired to be obtained according to the invention
25 is illustrated in FIG. 5. This preform, indicated with 9, is for realising (typically
through stretch blow molding) bottles in thermoplastic resin PET and comprises a
neck 91, having the final shape foreseen in the bottle, and a hollow body 92 intended,
in the realisation step of the bottle, to form the container body of the same.
Generally, the neck 91 is provided with projections which define, for example, a
30 thread 93 projecting radially outward suited to receive a common screw cap. The
hollow body 92 has on the other hand a continuous outer surface, generally nearly
cylindrical (slightly tapered toward the bottom for delivery reasons) and terminating

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in the lower end with a more or less spherical cap. In particular, the hollow body 92
comprises a side wall 92a, typically substantially cylindrical, and a bottom wall 92b,
typically in the form of a cap.
The preform 9 is obtained with a process of compression molding through the
5 pressure insertion of a punch 11 (male element of the mold) within a closed-cavity
hollow matrix (female part of the mold), loaded with a metered body 8 of polymeric
material (in particular a thermoplastic resin) at the more or less viscous pasty state,
whose mass is metered according to a reference value.
The molding machine which utilises the mold according to the invention is typically
10 but not exclusively of the continuously rotating turntable type, and typically but not
exclusively operates with a plurality of equal molding groups which are operated in
sequence.
Illustrated in the figures is only a generic meld according to the invention. The
machine on the other hand is not illustrated, being per se of traditional type.
15 The mold according to the invention comprises a matrix and a punch 11. Together,
punch 11 and matrix cavity give rise to a molding chamber 7 which confers the
desired shape to the preform 9. The cavity of the matrix confers shape to the outer
surface of the preform while the outer surface of the punch 11 confers shape to the
inner surface of the preform 9.
20 According to the embodiment illustrated in the figures, the matrix of the mold is
formed by:
an upper matrix part 20 having inner surface 21 adapted to form the outer surface of
the upper neck 91 of the preform, divided into at least two sectors adapted to be
distanced between each other to permit the extraction of the preform 9,
25 a lower matrix part 30 having inner surface adapted to form the outer surface of the
hollow body 92 of the preform.
The two upper 20 and lower 30 matrix parts may be separated from each other in the
loading step of the metered body 8, which is inserted in the cavity of the only lower
matrix part 30; the inner surface areas of said upper 20 and lower 30 matrix parts are
30 adapted, when they are operatively associated to each other, to form the entire cavity
of the matrix.
Alternatively, the two matrices are maintained associated to each other also in the

WO 2006/040631 PCT/IB2005/002671
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loading step of the metered body.
According to the invention, the lower matrix part 30 comprises an undeformable
support body 40 which houses at its interior at least one deformable wall 31 realised
in steel (or in an equivalent material) whose inner surface defines at least a part of
5 the inner surface of the lower matrix part, having at least a portion in the shape of
foil having a relatively thin thickness which permits it to be elastically deformed
under the pressure of the polymeric material in the final molding step of the preform
so to vary, in particular to increase, the thickness of the hollow body. The
deformation of the wall 31 occurs mainly by bending the section along the generic
10 axial plane, together with deformations by traction, while the thickness of the wall
does not undergo considerable variations.
According to the first embodiment, illustrated in Fig. 1, the lower matrix part 30
comprises a portion 38 having tubular form, in particular substantially cylindrical,
which defines said deformable wall 31, whose inner surface 31' confers the shape, at
15 least in part (and in particular, as illustrated, almost completely) of the outer surface
of the side wall 92a of the hollow body 92, which wall 31 has a relatively thin
thickness which permits it to be elastically deformed under the pressure of the
polymeric material.
The deformable wall 31 is housed, in particular it is enclosed, within a coaxial cavity
20 36 made in the support body 40; whose inner surface is placed a distance from the
outer surface of the wall 31, such that this may be radially deformed without being
hindered by the body 40 itself.
The deformable wall 31 comprises an enlarged section which defines a circular band
32 near the upper end and a second enlarged section, near the lower end, which
25 defines a second circular band 33. Said circular bands 32 and 33 have respective
outer cylindrical surfaces 32' and 33' which abut corresponding seats 34 and 35
made in the coaxial cavity 36 of the support body 40; thus defined are two circular
radial abutting zones for the wall 31 which also serve for the centring of the wall 31.
Said surfaces 32' and 33' are perfectly cylindrical so that the abutting operates only
30 in the radial direction. The upper band 32 also has a shoulder 32a which is blocked in
the axial direction by the seat 34.
Along the generic section in the axial plane, the deformable wall 31 comprises, from

WO 2006/040631 PCT/IB2005/002671
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one side and from the other with respect to the axis, two end portions defined by the
circular bands 32 and 33, which form abutments which hinder radial displacement
and a central portion, laminar and having a relatively thin thickness compared with
the axial length in a single body with the two end portions, free to elastically bend in
5 the radial direction, forming an arch in the axial plane.
In detail, the support body 40 comprises a first tubular body 41 and a second, upper
body 42 bound together with the first in monolithic manner by an outer envelope 43
and by an upper closing element 44 associated to the envelope 43. The cavity 36 is
made nearly entirely in the lower body 41.
!0 Inside the first body 41 an undeformable central body 45 is placed whose upper
surface 45' defines the outer surface of the bottom wall 92b of the hollow body 92.
The lower band 33 is also blocked in the axial direction by the respective seat 35.
More precisely, a lower shoulder is foreseen near the lower end of the inner wall 31
which comes into contact with the upper end edge of the central body 45 in order to
15 ensure the continuity between the inner surface 31' of the wall 31 and the upper
surface 45' of the central body 45.
The cavity 36 is connected, through conduits 46 and others (not illustrated), with
means adapted to introduce, circulate and discharge refrigerant fluids capable of
removing heat from the preform in a thermal conditioning step (cooling) of the same.
20 The deformable wall 31 lends itself in a particular manner to this end due to the fact
that it possesses a relatively thin thickness, which greatly favours the transmission of
heat through it.
Moreover, the deformable wall 31 may have different reliefs 37 placed along the
outer surface, which define the elements of thermal exchange; these elements are
25 interrupted in the circumferential direction in order not to hinder the elastic radial
dilation of the deformable wall 31 in the molding step.
In the embodiment illustrated in Fig. 1A e IB, the reliefs 37 have the shape of fins
which project radially and which extend for a distance in the axial direction; these
reliefs are moreover placed alternately between one line and the other in order to
30 realise maximum turbulence in the passage of the refrigerant fluid and therefore
maximise the thermal exchange with the wall 31.
In the embodiment illustrated in Fig. 1C the reliefs 37 have the shape of rings placed

WO 2006/040631 PCT/IB2005/002671
8
on planes transverse to the axis of the wall 31 and nevertheless interrupted in order to
not realise stiffening ribs which may hinder the radial dilation of the wall 31.
There may be foreseen, moreover, appropriate ducts (not shown in the figures)
adapted to cool and/or thermoregulate the central body 45 so to cool and/or
5 thermoregulate through such body the lower end portion of the preform.
The punch 11 is integrally fixed to an upper body 10 with which it forms a single
body and of which it defines the lower end portion, that which confers shape to the
inner surface of the preform. In detail, the upper body 10 comprises a shoulder
adapted to abut against the upper end 23 of the upper matrix part 20, and a lower
10 portion 10" which in its lower section is united to the punch 11 itself.
The upper surface 91b of the upper end edge of the neck 91 of the preform 9 is
formed in part by a narrow, downward-turned upper surface 21b, which terminates
with a substantially horizontal tengent which defines the upper border of the inner
surface 21 of the upper matrix part 20, and in part is formed by a narrow upper
15 surface 12b, downward-turned and terminating with a substantially horizontal
tangent, which defines the upper border of the outer surface of the punch 11, at the
border with the lower end of the lower portion 10" of the upper body 10 (see Fig.
ID).
When the two said upper surfaces 12b and 21b are aligned with each other, the mold
20 is then in closed position, i.e. the punch 11 and the matrix parts 20 and 30 are
mutually coupled such that the mold cavity defines the molding chamber 7 in which,
between the inner surface of the matrix parts 20 and 30 and the surface of the punch
11, lies defined the shape of the preform.
In operation, it is first foreseen (Fig. 2A) to insert in the cavity of the matrix a
25 metered body 8 of polymeric material, whose mass is metered according to a
reference value which is established such that, taken into account the error which
inevitably exists in the metering of such body, the body 8 itself always fills in a
complete manner the volume of the molding chamber 7 of the mold calculated "in
unloaded condition" and that the error proves to be an excess of polymeric material
30 with respect to the volume of the chamber itself.
Subsequently, the mutual approaching among the mold components is carried out,
for example, following a lifting of the lower matrix part 30, operated through a lower

WO 2006/040631 PCT/IB2005/002671
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device (not shown in the figures) while the upper body 10, which bears the punch 11,
and the punch itself on the other hand remain still.
In the figures from 2A to 2D a horizontal reference axis is indicated with an X,
which remains fixed, passing tlvrough the lower abutting shoulder of the upper
5 portion 10' of the body 10.
It is nevertheless obvious that that of importance here is the movement related to the
mutual approaching; this may be obtained, alternatively, following a downward
movement of the upper body 10, possibly together with an upward movement of the
lower device which bears the matrix.
10 First, (Fig. 2B) the punch 11 begins to penetrate into the cavity of the lower matrix
part 30, beginning to progressively deform the metering 8.
Subsequently, the upper end of the lower matrix part 30 comes to couple with the
lower end of the upper matrix part 20 (position illustrated in Fig. 2C) and the punch
11 continues to penetrate in the cavity of the matrix, continuing to deform the
15 metering 8. The sectors which form the upper matrix part 20 are locked in radially
closed position through an upper annular body 14 (of known type) associated to the
punch 11 and vertically moving with respect to it, whose lower end portion possesses
a concave frustoconical surface 14a, which mates with a complementary outer and
upper side surface 26 of the upper matrix part 20, it too of frustoconical shape.
20 Subsequently, the punch 11 continues to penetrate (always following upward
displacements of the lower device which bears the matrix) within the matrix cavity
until it produces the complete closing of the mold, which occurs when the two
surfaces 12b and 21b are in contact with each other (position shown in Fig, 2D). At
this point the penetration of the punch terminates.
25 During this final molding step of the preform, it occurs that first, when the molding
chamber 7 is still not closed, the polymeric material of the metering completely fills
such chamber 7, while the deformable wall 31 is not yet deformed, at least in
appreciable terms, achieving appropriately high pressure values, in the range of the
design values foreseen at the end of the molding. Then, the penetration of the punch
30 continuing further into the matrix cavity until the closing of the mold, since the
polymeric material has an excess volume with respect to the volume of the chamber
7, such material, pushed by the pressure produced by the penetration of the punch,

WO 2006/040631 PCT/IB2005/002671
10
causes the elastic wall 31, whose generic axial section is free to bend, not having any
constraint other than the abutments provided by the bands 32 and 33, to be elastically
deformed with outward radial displacement until said excess volume is absorbed.
5 The elastic deformation which the deformable wall 31 undergoes is of bending type
in the section along a generic axial plane, with displacement of the axially middle
zone of the wall itself which bends outward, said displacement being as great as said
excess volume of the metering. On the other hand, along the generic transverse
plane, the deformation which the elastic wall 31 undergoes, in tubular form
10 according to the first embodiment (fig. 1A), consists of an increase in the diameter of
the tubular wall itself which achieves maximum value in the axially middle zone.
The tubular wall 31 is therefore subject to stress composed of elastic bending and
traction together. The described deformation of the wall 31 illustrated in figures I
and 1A, produces a distributed and regular increase of the thickness of the side wall
15 92a of the hollow body 92 which achieves maximum value in the intermediate zone
thereof, while such thickness remains nearly unchanged at the bands 32 and 33 since
these are scarcely deformable.
The elastic deformation does not even involve other parts of the matrix, and in
particular the upper part 20 which gives shape to the neck 91, which remain instead
20 unaltered.
The error of the mass of the metering with respect to the reference value is therefore
distributed in the preform part placed at the deformable wall 31 and hence in the
hollow body 92.
The reference value of the mass of the metering 8 is calculated so that taking into
25 account both the error in the formation of the metering 8 and the volumetric
shrinkage which occurs in the cooling of the preform during the molding, the
complete filling of the molding chamber 7 is realised and moreover such that the
polymeric mass is subjected, in the final step of the molding, to a pressure having
appropriate design values (on the order of several hundred bar). In particular, it may
30 be foreseen that said reference value is such that the polymeric material of the
metering has always a greater volume than the volume of the molding chamber and
that therefore the deformable wall 7 always undergoes a deformation, of a more or

WO 2006/040631 PCT/IB2005/002671
11
less significant measure.
For its own part the deformable wall 31 is designed with structural characteristics (in
particular the material and the thickness in relation with the length) such that it can
be elastically deformed so to absorb the excess volume of the metering and provide
5 at the same time, in virtue of only its own structural characteristics (without the
intervention of outside means or actions), a sufficient resistance to elastic
deformation to allow that the polymeric material of the metering achieves in the final
molding step said design values regarding the pressure, where moreover the
deformation of the wall 31 takes place following the complete filling of the molding
10 chamber.
Therefore, the deformable wall 31 shall be sized in relation with several parameters
including the force of the molding in play and the size of the errors of the metering.
For example, for a preform having a mass of 24 grams, and having a totai axiai
length of 100 mm, it was utilised, in the lower matrix part 30, a deformable wall 31
15 in stainless steel, with low values of carbon and high values of Mo, Ni, Co and Ti,
whose thickness in the central part comprised between two abutments defined by the
bands 32 and 33 is approximately 2.5 mm. In the test operation, foreseeing for the
mass of the metered body 8 a maximum error of 1 %, radial deformations were
detected in the wall 31 on the order of 0.02-0.05 mm.
20 In the second embodiment, illustrated in Fig. 3, the deformable wall 31 comprises a
side portion 38 having tubular form (substantially equal to the whole wall 31 of the
first embodiment) in particular substantially cylindrical, whose inner surface 38'
defines at least in part (and in particular, as illustrated, nearly completely) the outer
surface of the side wall 92a of the hollow body 92, and also a bottom portion 39, in
25 the shape of a cap joined in a single body to the side portion 38, whose inner surface
39' defines the outer surface of the bottom wall 92b of the hollow body 92.
This deformable wall 31 has nearly entirely a relatively thin thickness which permits
it to be elastically deformed, under the pressure of the polymeric material, both in the
side portion 38 and in the bottom portion 39.
30 The two said circular bands 32 and 33 are present, placed at the respective upper and
lower ends of the side portion 38.
The coaxial cavity 36, in this case, also wraps around the bottom portion 39 of the

WO 2006/040631 PCT/IB2005/002671
12
wall 31.
Said lower seat 35, on which abuts the lower band 33, defines a cylindrical abutment
surface and is made on a limited number of radial and axial fins 48 which permit the
communication between the lower and upper part of the cavity 36.
5 The abutment between the band 33 and the respective abutment seat 35 permits the
axial sliding of the band itself, so to not hinder the axial elastic deformation of the
deformable wall 31.
Therefore, also in this second embodiment, as in the first, the deformable wall 31
comprises a deformable tubular portion 38 which has, along the generic axial section,
10 from one side and the other with respect to the axis, two end portions defined by the
circular bands 32 and 33, which form abutments which hinder the radial
displacement, and a central portion, laminar and having a relatively thin thickness in
relation with the axial length, in a single body with the two end portions, free to
elastically bend in radial direction, forming an arch in the axial plane. Moreover it
15 also comprises a deformable bottom portion 39 which has, along generic axial
section, two end portions, both defined by the circular band 33, and a central portion,
having a relatively thin thickness in relation with the length, free to elastically bend
in the axial direction.
The cavity 36 is connected, through a lower mouth 49 made in the central body 45b
20 and other not-illustrated conduits, with means adapted to circulate refrigerant fluids
capable of removing heat from the preform in a step of thermal conditioning
(cooling) of the same.
In operation, this embodiment differs from the preceding for the fact that the pressure
exerted by the metering 8 on the inner surface of the molding chamber 7 causes an
25 elastic deformation both of the side portion 38 and the bottom portion 39 of the
deformable wall 31 and therefore the error of the metering is apportioned also to the
bottom portion 92b, in addition to the side portion 92a of the hollow body 92.
Moreover, the deformable wall 31 is subject to both bending and axial elongation
deformations.
30 Also in the third embodiment, illustrated in Fig. 4, as in the second, the deformable
wall 31 comprises a side portion 38 having tubular form (substantially equal to the
whole wall 31 of the first embodiment) in particular substantially cylindrical, whose

WO 2006/040631 PCT/IB2005/002671
13
inner surface 38' defines at least in part (and in particular, as illustrated, almost
completely) the outer surface of the side wall 92a of the hollow body 92, and also a
bottom portion 39, in the shape of a cap joined to the side portion 38, whose inner
surface 39' defines the outer surface of the bottom wall 92b of the hollow body 92.
5 Nevertheless, unlike the second embodiment, this foresees that the two portions 38
and 39 are separated from each other and in any case associated to form a continuity
of the respective inner surfaces.
Said lower circular band 33 is made in the upper circular border of the bottom
portion 39 and in correspondence thereof the two portions 38 and 39 are mutually
10 fixed. The band 33 has a series of radial-axial ribs 51 whose free radial ends define a
cylindrical surface which abuts against the lower seat 35, it too cylindrical.
Here too, as in the preceding embodiment, the coaxial cavity 36 also wraps around
the bottom portion 39 of the wall 31 and the lower seat 35, and the ribs 51 permit the
communication between the lower part of the cavity 36 and the upper part thereof.
15 In particular, inside the tubular body 41 there is a central body 45b whose upper
surface is placed a distance from the lower surface of the bottom portion 39.
The abutment between the band 33 and the respective abutment seat 35 permits the
axial sliding of the band itself, so to not hinder the axial elastic deformation of the
deformable wall 31.
20 The cavity 36 is connected, through a lower mouth 52 made in the central body 45b
and other not-illustrated conduits, with means adapted to circulate refrigerant fluids
in the cavity 36 itself capable of removing heat from the preform in a step of thermal
conditioning (cooling) of the same. In the lower part of the cavity 36, below the
abutment ribs 51, there are several fins 53 projecting upward from the central body
25 45b, adapted to better direct the flux of the refrigerant fluid, and which do not hinder
the deformation of the wall 31 with which they do not come into contact. Also in this
third embodiment, the error of the metering is apportioned also to the bottom portion
92b, in addition to the side portion 92a of the hollow body 92.
There may moreover be foreseen several conduits 54, made in the support body 40,
30 in particular in the central body 45b and in the fins 53, which cross the ribs 51 and
the lower band 33, which lead in correspondence with the surfaces of mutual
connection between the lower end of the side portion 38 and the upper end of the

WO 2006/040631 PCT/IB2005/002671
14
bottom portion 39.
Said conduits 54 may be advantageously connected with suction means in order to
clear the air present in the cavity of the mold before and during the compression step
of the metering.
5 Moreover, or alternatively, the conduits 54 may be advantageously connected with
means adapted to inject air or another thermally conditioned fluid inside the cavity,
before the opening step of the mold, to favour the cooling and the detachment of the
preform after its molding.
The fourth embodiment (Fig. 6) consists of a variation of the first embodiment
10 (figure 1 and 1A) in which the central body 45 was modified according to the
teaching of the invention described in the patent application n. PCT/IB2005/002303
(claiming the priority of the Italian patent application n.RE2004A000127 of the same
Applicant), mainiy in order to increase the capacity of the matrix to receive the
metering. In particular, the central body 45 is realised so to comprise a first
15 component body 451 and a second component body 452, situated centrally with
regards to the first, having respectively inner surfaces 453 and 454 which may be
aligned in a complementary manner to define, together, the inner surface 45'.
The first component body 451 is integrally fixed to the remaining lower matrix part,
in particular it is integrally fixed to the body 41. The second component body 452 is
20 movable with respect to the first component body 451 between an upper position
(illustrated with a continuous line in Fig. 6) in which its inner surface 454 is placed
in aligned or nearly aligned position with the inner surface 453 of the first
component body 451 and a back position (illustrated with a dashed line in Fig. 6) in
which its inner surface 454 is placed a distance from the inner surface of the first
25 component body in order to increase the volume of the cavity of the lower part of the
matrix. Finally, operation means are foreseen (not illustrated in the figures) adapted
to arrange said second component body in said back position in the loading step of a
metering of polymeric material in the cavity of the lower matrix part 30 and to bring
it to the upper position in the molding step.
30 In operation, first a metering is formed outside of the mold and then inserted in the
cavity of the lower matrix part, while the second component body 452 is in said back
position.

WO 2006/040631 PCT/IB2005/002671
15
Subsequently, the progressive insertion of the punch in the matrix cavity is carried
out until the closing of the mold, with modalities equal or similar to those described
above with reference to the figures 2A to 2D, while the second component body 452
is maintained in said back position.
5 Once the complete penetration of the punch 11 in the matrix cavity is realised until
the closing of the mold (in which the lower matrix part 30 is coupled with the upper
part 20 and the two surfaces 12b and 21b are in mutual contact), the upward
displacement is produced of the second component body 452 until it reaches the
upper position. This final step may begin after the closing of the mold, or a little
10 before.
In this last step, the polymeric material is pushed to completely fill the molding
chamber and then to deform the elastic wall 31, thereby increasing the thickness of
the hollow body, until the excess volume of the metering is absorbed.
The upper position does not necessarily coincide with the position in which the
15 surface 454 of the second component body 452 represents the exact geometric
continuation of the surface 453 of the other component body 451 ("nominal position"
of design) but is separated from this in a variable manner, in relation with a level of
error of the mass of the metering. This upper position may therefore result below
said "nominal position".
20 According to a further embodiment (not shown in the figures) it is foreseen that
said deformable inner wall 31 comprises only the bottom portion and that therefore
the error of the metering is apportioned only to the bottom portion 92b of the hollow
body 92.
According to the invention, the preform, after its molding, is cooled and
25 subsequently subjected to a process of deformation through stretch blow molding in
which the hollow body is newly heated, until the desired shape of the container is
achieved. Alternatively, the preform is subjected to the process of deformation
through stretch blow molding v/hile the temperature of its hollow body is still
sufficiently hot.
30 Thanks to the invention, firstly, the error of the mass of the metering is distributed in
a continuous manner and over a relatively quite wide surface such that no trace is left
in the exterior aspect of the final containers which are obtained at the end of the

WO 2006/040631 PCT/IB2005/002671
16
entire process; nor is it possible to perceive, in practice, size variations between one
final container and the other.
Moreover, after the molding of the preform, the possible further tensions which form
in the distribution of the error of the metered body in the hollow body are eliminated
5 with the hollow body's subsequent heating; or else such tensions do not even form
since the temperature of the hollow body is maintained sufficiently high and the mass
is maintained in a more or less viscous fluid state.
The fourth embodiment (Fig. 6) increases the volume of the cavity of the lower
matrix part, with respect to that of a traditional mold, in the step in which it receives
10 the metering, and thus renders such cavity capable of receiving metered bodies
having higher mass and/or height than would otherwise be receivable. Moreover, it
renders possible the compensation of relatively greater mass errors, thanks to the fact
that to the compensation which is obtained through the elastic deformation of the
elastic wall 31 a compensation may be added, obtained by ensuring that the upper
15 position of the component body 452 does not exactly coincide with said "nominal
position", but is separated from this to compensate for at least a part of the metering
error.

22-12-2006

IB20050026

27182 REPLACEMENT PAGE
17
CLAIMS
1. Method for making concave objects in polymeric material, comprising:
- compression molding of preforms comprising an upper neck which maintains
5 the same form of the final concave object and a hollow body, joined to the neck,
and
-the subsequent deformation treatment of the hollow body under hot
temperature wherein it is dilated to assume a greater capacity and a
correspondingly reduced thickness;
10 the compression molding of preforms comprising:
- providing a mould having a matrix comprising a first part (20) to form the outer
surface of the upper neck (91) and a second matrix part (30) to form the outer
surface of the hollow body (92), and a punch to form the inner surface of the
preform, the second matrix part (30) comprising a defcrrnable wa!! (31);
15 - inserting a metered mass body of polymeric material within a matrix cavity,
the reference mass value of the metered body being calculated such that an
error results as an excess mass of polymeric material, and
- pressure inserting the punch into the matrix cavity with progressive movement
relatively to it until the mold is in a closed position and the polymeric material
20 completely fills the mould molding chamber in the insertion final step, wherein
the punch insertion causes the elastic deformation of said deformable wall (31)
to adsorb the error of the metered mass body, the excess mass being
distributed along the whole perimeter of the hollow body transversal section to
increase its thickness.
25
2. Method according to claim 1, characterised in that after the molding of the
preform, the hollow body is subject to a cooling and to a subsequent heating and
deformation treatment until it achieves the final shape.
30 3. Method according to claim 1, characterised in that, in the molding of the
preform, a side portion (38) of the elastic wall (31) having tubular form ), is
elastically deformed to distribute the excess of the metered mass body, at least
in part, in the side wall (92a) of the hollow body (92).
35 4. Method according to claim 3, characterised in that in said final step of the
punch penetration, the polymeric material of the metered body completely fills
the molding chamber (7) and the volume of the excess polymeric material.

AMENDED SHEET

22-12-2006 IB20050026'
27182 REPLACEMENT PAGE
18
pushed by the penetration of the punch, causes the the pressure value of the
polymeric material to reach a value substantially equal to a pre-established value
in virtue of the resistance to elastic deformation produced by deformable wall
(31) without the intervention of external means or actions.
5
5. Method according to claim 3, characterised in that in the molding of the
preform at least part of the inner surface of the matrix is elastically deformed with
respect to its position "in unloaded condition", such in a way to increase the
length of the hollow body so to absorb the excess of polymeric material.
10
6. Preform in polymeric material intended for the molding of concave
objects, formed through the method of claim 1.
7. Mold for the compression molding of preforms in polymsric material
15 intended for the molding of concave objects,
the preform comprising an upper neck which maintains the same form in the final
object and a hollow body joined to the neck,
wherein the compression molding process comprises the insertion of a mass
body of polymeric material, metered with an excess error, into the mold and the
20 pressure insertion of the punch within the matrix cavity with progressive
movement relatively to it, until the mold is in a closed position and the polymeric
material completely fills the mould molding chamber in the insertion final step,
the mold comprising:
a matrix having a part (20) to form the outer surface of the upper neck (91) and
25 another matrix part (30) to form the outer surface of the hollow body (92), and
a punch for forming the inner surface of the preform;
the matrix comprising at least one deformable wall (31) whose inner surface
defines at least a part of the inner surface of the matrix part to form the hollow
body (92) of the preform, said deformable wall (31) having, at least in part, a
30 relatively thin thickness
characterised in that said deformable wall (31) is elastically deformable, under
the pressure of the polymeric material produced by said punch insertion, such in
a way to increase the thickness of the hollow body to adsorb the excess error,
and its structural characteristics1 are able to provide the whole resistance to said
35 elastic deformation without intervention of external means or actions.
AMFNHFn SHFFT

22-12-2006 IB20050026";
27182 REPLACEMENT PAGE
19
8. Mold according to claim 7, characterised in that the structural characteristics
of the deformable wall (31) are able to provide resistance to said elastic
deformation without the intervention of external means or actions, so that the
polymeric material achieves a pressure value substantially equal to a project
5 pressure value in said punch insertion final step.
9. Mold according to claim 7, characterised in that said deformable wall (31)
is realised in steel or equivalent material.
10 10. Mold according to claim 7, characterised in that said deformable wall (31),
comprises a side portion (38) having tubular form whose inner surface (38')
defines at least in part the outer surface of the side wall (92a) of the hollow body
(92).
15 11. Mold according to claim 9, characterised in that the deformable wall (31) has
at least one end portion (33) sliding on respective abutment seat (35) so to not
hinder the axial component of the elastic deformation of the deformable wall
(31).
20 12. Mold according to claim 10, characterised in that the deformable wall
(31) comprises at least a portion (38) having, in the section along the generic
axial plane, two end portions having abutments which prevent the displacements
in the radial direction and a central portion, free to elastically bend in the radial
direction.
25
13. Mold according to claim 10, characterised in that it comprises a central
body (45) whose surface (45') defines the outer surface of the bottom wall of the
preform, said central body 45 comprising a first fixed component body (451) and
a second movable component body (452), having inner surfaces (453, 454)
30 which may be aligned in complementary manner to define, together, the inner
surface (45'), said second component body 452 being movable with respect to
the first component body (451) between an upper position in which its inner
surface (454) is placed in aligned or nearly aligned position with the inner
surface (453) of the first component body (451) and a back position in which its
35 inner surface (454) is placed a distance from the inner surface of the first
component body so to increase the volume of the cavity of the lower part of the
matrix,
AMENDED SHEET

22-12-2006 IB20050026:
27182 REPLACEMENT PAGE
20
there being foreseen in addition operation means adapted to arrange said
second component body (452) in said back position in the loading step of a
metering of polymeric material in the cavity of the lower matrix part (30) and to
bring it to the upper position in the molding step.
5
14. Mold according to claim 10, characterised in that the deformable wall
(31) comprises a bottom portion (39) whose inner surface (391) defines, at least
in part, the outer surface of the bottom wall (92b) of the hollow body (92).
10 15. Mold according to claim 10, characterised in that said deformable wall
(31) has a circular band (32) at the upper end and a second circular band (33) at
the lower end, said circular bands (32, 33) providing zones of radial abutment for
the deformable wall (31).
15 16. Mold according to claim 15, characterised in that the abutment between
the lower band (33) and the respective abutment seat (35) permits the axial
sliding of the band itself, so to not hinder the axial component of the elastic
deformation of the deformable wall (31).
20 17. Mold according to claim 10, characterised in that the deformable wall
(31) is enclosed within a coaxial cavity (36) made in the support body (40)
whose inner surface is placed a distance from the outer surface of the wall (31),
so that this may be deformed without being hindered by the support body (40)
itself.
25
18. Mold according to claim 10, characterised in that said deformable wall
(31) has reliefs (37) placed on the outer surface which define elements of
thermal exchange, interrupted along the circumferential direction in order to not
hinder the elastic deformation of the deformable wall (31).
30
19. Mold according to claim 18, characterised in that the reliefs (37) are
shaped as fins which project radially and extend for a distance in the axial
direction, said reliefs (37) being moreover placed in alternate manner between
one line and the next in order to realise the maximum turbulence in the passage
35 of the refrigerant fluid.
20. Mold according to claim 10, characterised in that the deformable wall
AMENDED SHEET

22-12-2006 IB20050026'
27182 REPLACEMENT PAGE
21
(31) comprises a side portion (38) and a bottom portion (39) which are separated
from each other and in any case associated to form continuity of their respective
inner surfaces.
5 21. Mold according to claim 20, characterised in that it comprises at least one
conduit (54), which leads in correspondence with the surfaces of mutual
connection between the lower end of the side portion (38) and the upper end of
the bottom portion (39), said conduit (54) being connected with suction means
adapted to clear the air present in the cavity of the mold before and during the
10 compression step of the metering.
22. Mold according to claim 20, characterised in that it comprises at least one
conduit (54), which across the deformable wall (31) leads in correspondence
with the surfaces of mutual connection between the lower end of the side portion
15 (38) and the upper end of the bottom portion (39), said conduit (54) being
connected with means adapted to inject air or other thermally conditioned fluid
inside the cavity, before the opening step of the mold, to favour the cooling and
the detachment of the preform.
AMENDED SHEET

The preform is formed by an upper neck which
maintains unchanged its form in the final object and a hollow body,
joined to the neck. The method foresees the insertion, within a
matrix cavity, of a metered body of polymeric material whose
mass is metered according to a reference value, and the subsequent
pressure insertion of a punch within the matrix cavity until it closes
the mold's molding chamber, the punch conferring the shape to
the inner surface of the preform and the matrix having an inner
surface which confers the shape to the outer surface of the preform.
According to the invention, in the molding of the preform, the error
of the mass of the metered body with respect to the reference value
is distributed in the hollow body, which undergoes a subsequent
hot deformation until it achieves the final shape. In the mold, the
matrix comprises at least one deformable wall (31) whose inner
surface defines at least part of the inner surface of the matrix part
intended to give form to the hollow body of the preform, said
deformable wall (31) having, at least in part, a relatively thin
thickness which permits it to be elastically deformed under the
pressure of the polymeric material in the final preform molding
step, thereby varying the thickness of the hollow body.

Documents:

01095-kolnp-2007-abstract.pdf

01095-kolnp-2007-assignment.pdf

01095-kolnp-2007-claims 1.0.pdf

01095-kolnp-2007-claims 1.1.pdf

01095-kolnp-2007-claims 1.2.pdf

01095-kolnp-2007-correspondence others.pdf

01095-kolnp-2007-description complete.pdf

01095-kolnp-2007-drawings.pdf

01095-kolnp-2007-form 1.pdf

01095-kolnp-2007-form 3 1.1.pdf

01095-kolnp-2007-form 3.pdf

01095-kolnp-2007-form 5.pdf

01095-kolnp-2007-gpa.pdf

01095-kolnp-2007-international publication.pdf

01095-kolnp-2007-international search report.pdf

01095-kolnp-2007-pct forms.pdf

01095-kolnp-2007-pct others.pdf

01095-kolnp-2007-priority document.pdf

1095-KOLNP-2007-(27-12-2011)-ABSTRACT.pdf

1095-KOLNP-2007-(27-12-2011)-AMANDED CLAIMS.pdf

1095-KOLNP-2007-(27-12-2011)-AMANDED PAGES OF SPECIFICATION.pdf

1095-KOLNP-2007-(27-12-2011)-DESCRIPTION (COMPLETE).pdf

1095-KOLNP-2007-(27-12-2011)-DRAWINGS.pdf

1095-KOLNP-2007-(27-12-2011)-EXAMINATION REPORT REPLY RECEIVED.pdf

1095-KOLNP-2007-(27-12-2011)-FORM-1.pdf

1095-KOLNP-2007-(27-12-2011)-FORM-2.pdf

1095-KOLNP-2007-(27-12-2011)-FORM-3.pdf

1095-KOLNP-2007-(27-12-2011)-OTHER PATENT DOCUMENT.pdf

1095-KOLNP-2007-(27-12-2011)-OTHERS.pdf

1095-KOLNP-2007-ASSIGNMENT.pdf

1095-KOLNP-2007-CORRESPONDENCE.pdf

1095-KOLNP-2007-EXAMINATION REPORT.pdf

1095-KOLNP-2007-FORM 18.pdf

1095-KOLNP-2007-FORM 3.pdf

1095-KOLNP-2007-FORM 5.pdf

1095-KOLNP-2007-GPA.pdf

1095-KOLNP-2007-GRANTED-ABSTRACT.pdf

1095-KOLNP-2007-GRANTED-CLAIMS.pdf

1095-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

1095-KOLNP-2007-GRANTED-DRAWINGS.pdf

1095-KOLNP-2007-GRANTED-FORM 1.pdf

1095-KOLNP-2007-GRANTED-FORM 2.pdf

1095-KOLNP-2007-GRANTED-SPECIFICATION.pdf

1095-KOLNP-2007-OTHERS.pdf

1095-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf

1095-KOLNP-2007-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

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Patent Number

253518

Indian Patent Application Number

1095/KOLNP/2007

PG Journal Number

30/2012

Publication Date

27-Jul-2012

Grant Date

26-Jul-2012

Date of Filing

28-Mar-2007

Name of Patentee

SACMI COOPERATIVE MECCANICI IMOLA SOCIETA COOPERATIVA

Applicant Address

17/A, VIA SELICE PROVINCIALE, I-40026, IMOLA (BOLOGNA), ITALY

Inventors:

#	Inventor's Name	Inventor's Address
1	BALBONI, ALESSANDRO	10, VIA BUDAPEST, I-40057 GRANAROLO, DELL'EMILIA(BOLOGNA) ITALY
2	ZUFFA, ZENO	6 VIA RAGGI, I - 40021, BORGO TOSSIGNANO (BOLOGNA) ITALY
3	PARRINELLO, FIORENZO	122/A, VIA ZANARDI, I - 40059, MEDICINA (BOLOGNA) ITALY

PCT International Classification Number

B29C 43/36

PCT International Application Number

PCT/IB2005/002671

PCT International Filing date

2005-09-09

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	RE2004A000127	2004-10-12	Italy