Method for manufacturing a metal packaging in the form of a bottle

Abstract

The invention relates to a method for manufacturing a metal packaging (1) in the form of a bottle. The method comprises a step of forming a tubular part (16), in order to form a threaded neck (3). This manufacturing method comprises, prior to at least one operation for forming a roll (7), preferably prior to the step of forming the tubular part (16), a step of localised annealing which is carried out in order to confer an annealed state on the tubular part (16), at least over the height of a downstream strip (162) of the tubular part (16) intended to be formed into a roll (7).

Description

Technical field of the invention

[0001] The present invention relates to the technical field of bottle-shaped metal packaging.

[0002] It relates in particular to the processes for the manufacture of such bottle-shaped metal packaging, the neck of which includes at least one roll, one thread and one transport ring. State of the art

[0003] Some bottle-shaped packages have a threaded neck which is hermetically sealed, after filling, by means of a cap.

[0004] The design of such packaging must take into account the constraints related to its manufacture, but also to its numerous handling at the filler from its receipt to the final packaging operations.

[0005] However, depending on their constituent material, packaging is obtained through manufacturing techniques that generate structural constraints leading to the implementation of dedicated conveying installations.

[0006] In this regard, the tubular part forming the neck of packaging made of plastic material (such as bottles or flasks) generally has an annular ring, protruding on the circumference and designated as a "transport ring", useful for their individual handling.

[0007] These plastic packages can thus be held, handled and / or transferred by positioning a handling device generally shaped like a fork, resting under this transport ring.

[0008] In practice, for such plastic packaging, the neck and its transport ring are formed simultaneously, for example on a preform (semi-finished part obtained by injection) before finishing by injection-blowing or extrusion-blowing.

[0009] Packaging made from metallic material, for example steel or aluminum, often lacks such a transport ring due to technical constraints related to metal forming.

[0010] The manufacture, handling and filling of such metal packaging thus leads to the implementation of dedicated handling equipment.

[0011] Therefore, for the filler, the switch from plastic packaging to metal packaging requires significant investments, particularly for the transformation of handling equipment.

[0012] To overcome this problem, there are developments of metal packaging whose threaded neck, including a terminal roll and a transport ring, would be adapted for handling within an installation usually dedicated to plastic packaging.

[0013] However, in practice, the technical constraints associated with metal forming create weaknesses during the forming of this threaded neck. The threaded neck of the metal bottle must also be able to withstand the capping forces, while allowing for a reduction in the metal's thickness.

[0014] In view of the above, there is a need for a technical solution that would allow the manufacture of metal bottles that have a threaded neck suitable for receiving a cap and that would be compatible with plastic bottle filling lines, while allowing a reduction in the thickness of its metal wall.

[0015] Document WO 2015 / 054284 A2 discloses a method for manufacturing a bottle-shaped metal package according to the preamble of the attached claim 1. Presentation of the invention

[0016] In order to remedy the aforementioned drawback of the prior art, the present invention proposes a method for manufacturing such bottle-shaped metal packaging, the neck of which includes at least one roll, one thread and one transport ring.

[0017] More specifically, the invention proposes a method for manufacturing a metal bottle-shaped package, said metal package comprising a body connected to a threaded neck by means of a shoulder.

[0018] The method according to the invention comprises: a manufacturing step of a preform comprising a tubular part, defining a longitudinal axis and a free downstream edge, which tubular part is connected to a body via a shoulder, and a forming step of said tubular part, to form said threaded neck.

[0019] The forming stage includes forming operations adapted to form monobloc structures on said tubular part: an operation of forming a roll within a downstream band of said tubular part, terminated by said downstream edge, to form a roll at the level of the downstream edge of the threaded neck, an operation of forming a thread within an intermediate band of said tubular part, and an operation of forming a transport ring within an upstream band of said tubular part, on the shoulder side, intended to cooperate with a handling member (said transport ring advantageously comprising at least one molding which is provided on a plane extending perpendicularly to said longitudinal axis and on the circumference of the tubular part, which at least one molding has a lower and / or upper surface against which a handling member is intended to bear).

[0020] And according to the invention, the manufacturing process includes, prior at least to said rolling operation, preferably prior to said tubular part forming step, a localized annealing step which is carried out to give the tubular part an annealed state, at least over the height of the downstream band of said tubular part.

[0021] According to the invention, the localized annealing step is performed to impart an annealed state only at the level of said downstream strip, or only at the level of the downstream and upstream strips, so as to retain at least part of the height of the interlayer strip in an unannealed state.

[0022] The present invention thus offers a technical solution which would allow the manufacture of metal bottles having a threaded neck adapted to receive a cap and which would be compatible with plastic bottle filling lines, while allowing a reduction in the thickness of its metal wall.

[0023] Indeed, the rolled section is formed above the thread, at the end of the tubular portion of the preform. Frequently, the metal that was stretched to form the preform is then re-shrunk to form the threaded neck; however, the applicant has observed that the metal is prone to tearing during the rolling process. This results in a significant proportion of production being discarded.

[0024] The applicant noted that annealing this area, by improving its formability, reduces the rate of cut collars.

[0025] Other non-limiting and advantageous features of the process according to the invention, taken individually or in all technically possible combinations, are as follows: the localized annealing step is carried out to impart an annealed state over a height of at least 3 to 7 mm of the downstream band of said tubular part; the localized annealing step is carried out to impart an annealed state over the height of the upstream band of said tubular part, advantageously over a height of 5 to 15 mm;the preform manufacturing step includes a deformation phase of a metal part to obtain a primary preform comprising a bottom extended by a tubular wall, for example chosen from deep drawing and / or drawing and / or reverse extrusion, for example by deep drawing and / or drawing of a metal blank for, for example, a thickness ranging from 0.2 mm to 0.7 mm, advantageously by a technique chosen from deep drawing / drawing or deep drawing and re-drawing (Drawing and Wall Ironing (DWI) or Draw and Re Draw process (DRD)) or reverse extrusion from a pin of 2 to 15 mm, a trimming phase, to form a downstream edge of said primary preform, and a shrinking step, to form said tubular part of a secondary preform; and said localized annealing step is applied to the tubular wall of the primary preform, before said shrinking step;The localized annealing step is implemented by an induction technique, advantageously within a tunnel inductor, advantageously with rotation of the preform; the process includes a shrinking operation of the downstream strip of the tubular part prior to the rolling operation; said rolling operation is adjusted to form said rolling outwards and such that the outside diameter of said rolling is less than or equal to the root diameter of the thread; the forming operation of the transport ring is implemented before the rolling operation; the transport ring is advantageously used for holding the tubular part during said rolling operation; the thread forming operation is applied to an intermediate strip having a height of 10 to 25 mm;the tubular part forming step further includes a tamper-evident counter-ring forming operation within an additional band of the tubular part, located between the interlayer band and the upstream band, forming a tamper-evident counter-ring groove between said tamper-evident counter-ring and said transport ring; the process further includes a varnishing phase, preferably an external varnishing phase and an internal varnishing phase carried out after the localized annealing step; the metal packaging is made of an aluminum alloy of the 3000 or 5000 series, for example an aluminum alloy 3104;the transport ring forming operation is chosen from a molding technique, for example by internal pressure exerted by a pressurized fluid or by the compression of an elastomer, which causes the wall to conform to the shape of a mold, or a direct mechanical action by a moving tool, for example by pushing the metal by rotating a roller on the inner face of the tubular part while an external roller, opposite the first, holds the metal, or an over- and under-shrunk technique; the transport ring forming operation includes a calibration phase to give a final shape to said transport ring;In this case, preferably, the calibration phase advantageously consists of bringing the upper and lower connecting radii of the transport ring into contact with each other, or of obtaining an upper and lower connecting radius of the transport ring which are radially offset from each other, with said lower connecting radius advantageously bearing against the upper surface of the transport ring, in particular to ensure the transfer of the axial force towards the transport ring during capping, and / or of bringing the external radius of the transport ring to a minimum radius acceptable by the constituent material;The calibration phase is advantageously carried out by pinching the annular deformation between two calibration rings that are coaxial with the longitudinal axis of the tubular part, or by two rollers rotating around the tubular part, advantageously with the introduction into the tubular part of a centering mandrel during calibration to ensure the concentricity of the parts above and below the tubular part; during the forming operation of the transport ring, an axial load is exerted on the metal packaging to accompany the metal in its deformation and prevent thinning and breakage; the process further includes a step of placing a metal cap on the threaded neck.

[0026] The present invention also relates to the metallic packaging, in the shape of a bottle, resulting from a process according to the invention.

[0027] Of course, the different features, variants and embodiments of the invention can be combined with each other in various ways as long as they are not incompatible or mutually exclusive. Detailed description of the invention

[0028] Furthermore, various other features of the invention become apparent from the attached description made with reference to the drawings which illustrate non-limiting embodiments of the invention and where: [ Fig. 1 ] is a general and schematic view of a bottle-shaped metal package produced by the manufacturing process according to the invention; [ Fig. 2 ] is a schematic and partial view of the metal packaging according to the figure 1 illustrating its threaded collar in more detail; [ Fig. 3 ] is a schematic, cross-sectional view of a step in the application of a metal cap onto the threaded neck; Fig. 4] is a schematic view illustrating the main phases / steps of the manufacturing process according to the invention for the manufacture of the bottle-shaped metal packaging; [ Fig. 5 ] is a schematic view of the localized annealing step that is applied to a preform during the manufacturing process according to the invention; [ Fig. 6 ] is a schematic view of the operation of forming the transport ring using a compression molding technique on an elastomer; [ Fig. 7 ] is a schematic view of the forming operation of the transport ring using a molding technique with internal pressure exerted by a pressurized fluid; [ Fig. 8 ] is a schematic view of the operation of forming the transport ring by direct mechanical action using expandable segments; ] Fig. 9] is also a schematic view of the operation of forming the transport ring by direct mechanical action by pushing the metal back through the rotation of an internal / external roller couple; [ Fig. 10 ] is a schematic view illustrating an axial load exerted on the metal packaging during the forming operation of the transport ring; [ Fig. 11 ] is a schematic view illustrating the forming operation of the transport ring by above and below shrinkages applied in the tubular part; Fig. 12 ] is a schematic view of a calibration phase of the transport ring, to give a final shape to said transport ring, by the implementation of two calibration rings; ] Fig. 13 ] is a schematic view of a calibration phase of the transport ring, to give a final shape to said transport ring, by the use of two rotating wheels; [ Fig. 14] is a schematic, partial, cross-sectional view of a threaded neck after the calibration phase, in which the upper and lower connecting radii of the transport ring are in contact with each other; [ Fig. 15 ] is still a schematic, partial and cross-sectional view of a threaded neck after the calibration phase, in which the upper connection radius and the lower connection radius of the transport ring are offset from each other.

[0029] It should be noted that, in these figures, the structural and / or functional elements common to the different variants may have the same references.

[0030] THE figures 1 to 3 thus represent a metallic, bottle-shaped packaging resulting from the process according to the invention.

[0031] Generally, such metal packaging is advantageously made of aluminum or steel.

[0032] As an example only, the metal packaging 1 is made from an aluminum alloy of the 3000 or 5000 series, for example an aluminum alloy 3104.

[0033] Such a metal packaging 1 advantageously consists of a container or receptacle, intended to receive for example a liquid product (in particular drinks), a pasty product or a solid product (in particular powders or granules).

[0034] This metal packaging 1 consists for example of a bottle, a flask or a canister.

[0035] This metal packaging 1 is advantageously designed to be hermetically sealed, after filling, by means of a metal cap C, advantageously conventional in itself (described below in relation to the figure 3 ).

[0036] In general, such a metal capsule C advantageously comprises: a base C1 equipped with a compressible seal C2, a skirt C3, intended to cooperate with a thread, and advantageously a tamper-evident ring C4.

[0037] The metal packaging 1, in the shape of a bottle, advantageously comprises a body 2 (or belly) which is connected to a threaded neck 3 (or neck) by means of a shoulder 4.

[0038] The threaded collar 3 defines a longitudinal axis 3', here oriented vertically and advantageously coaxial with the body 2.

[0039] This threaded collar 3 consists of a single-piece metal wall 5 which defines its circumference and delimits an internal conduit T terminated at a downstream opening 6 opposite the shoulder 4 ( figures 2 And 3 ).

[0040] The general horizontal section of this threaded collar 3, perpendicular to the longitudinal axis 3', is here circular in shape; it could just as easily be oval, rectangular or square for example.

[0041] The threaded neck 3 of this metal packaging 1 comprises a succession of monobloc structures, illustrated in particular on the figures 2 And 3 namely: a rolled 7, at the level of the downstream opening 6 of the threaded neck 3, advantageously designed to cooperate with the base C1 of capsule C (see in particular the figure 3 ), a thread 8, advantageously intended to cooperate with the capsule C3 skirt, a transport ring 9, on the shoulder side 4, intended to cooperate with a handling member (not shown), and optionally a tamper-evident counter-ring 10, forming a tamper-evident counter-ring groove 11 with the transport ring 9, advantageously intended to cooperate with the tamper-evident ring C4 of capsule C.

[0042] The downstream opening 6 of the tubular part 1 is formed here by the rolled section 7 which is oriented outwards, delimiting this downstream opening 6 of the inner conduit T ( figures 1 and 2 ).

[0043] Thread 8 forms means for receiving a cap or a capsule ( figure 3 ), in this case in the form of a helical net.

[0044] The transport ring 9 advantageously comprising at least one molding 9 which is provided on a plane extending perpendicularly to the longitudinal axis 3' and on the circumference of the threaded neck 3.

[0045] Said at least one molding 9 has a lower surface 91 and / or upper surface 92 against which a handling device (not shown) is intended to rest.

[0046] This handling device (not shown) advantageously has a fork shape, of the type classically encountered in the field of handling plastic bottles equipped with a transport ring.

[0047] The term "molding" refers in particular to a rib in the monobloc metal wall 5 (commonly referred to in English as " bead" , in intaglio or relief, obtained for example by striking or embossing.

[0048] The molding 9 is continuous here, extending over the entire circumference of the threaded collar 3.

[0049] The molding 9 is here provided in projection towards the outside of the threaded collar 3.

[0050] The vertical section of this molding 9 is advantageously identical or at least approximately identical over its circumference, without geometric break.

[0051] In general, the lower 91 and upper 92 surfaces of said at least one molding 9 advantageously have a crown shape.

[0052] This at least one molding 9 is further defined by different radii: a lower connecting radius 93, on the shoulder side 4, an upper connecting radius 94, on the thread side 8, an external radius 95, connecting the two lower surfaces 91 and upper surface 92.

[0053] Advantageous characteristics relating to the shape of this molding 9, as well as its forming and calibration, will be described in more detail later in relation to the figures 6 and following.

[0054] In general, the present invention relates to the method for manufacturing such a metal packaging 1 in the shape of a bottle.

[0055] As illustrated on the figure 4 The manufacturing process according to the invention comprises successive steps: a manufacturing step of a preform 15 comprising a tubular part 16 (intended to be subsequently formed to constitute the threaded neck 3) which is connected to the body 2 by means of a shoulder 4 (items A and B of the figure 4 ), then a forming step of this tubular part 16, to form the threaded collar 3 (items C to F of the figure 4 ).

[0056] In particular, the tubular part 16, intended to form the threaded neck 3 after forming, defines a longitudinal axis 16' and a free downstream edge 161.

[0057] For the manufacture of the threaded neck 3 in this tubular part 16, the forming step includes forming operations of the one-piece metal wall 5 which are adapted to form the different one-piece structures 7, 8, 9 and 10 of the threaded neck 3 within superimposed strips of the tubular part 16.

[0058] In this case, as further illustrated on the figure 4 The forming operations include: a rolling operation 7 within a downstream band 162 of the tubular part 16, ending with the downstream edge 161, to form the rolling 7 at the level of this downstream edge 161 of the threaded neck 3 (items E and F of the figure 4 ), a thread forming operation 8 within an intermediate strip 163 of the tubular part 16 (items D and E of the figure 4), and a forming operation of the transport ring 9 within an upstream band 164 of the tubular part 16, on the shoulder side 4, by a metal fold forming an annular deformation (items B to D of the figure 4 ), and possibly a forming operation of the tamper-evident counter-ring 10 within an additional band 165 of the tubular part 16, located between the intermediate band 163 and the upstream band 164.

[0059] According to a particular embodiment, the forming step of the tubular part 16 includes a shrinking operation of the downstream strip 162 of the tubular part 16, prior to the forming operation of the rolled section 7 (see item B of the figure 4 ).

[0060] The forming operation of the rolled part 7 is then advantageously adjusted to form the rolled part 7 outwards and so that the outside diameter of this rolled part 7 is less than or equal to the root diameter of the thread 8 (see in particular the figure 3 ).

[0061] According to the embodiment illustrated on the figure 4 , the forming operation of the transport ring 9 (items C and D) is implemented before the forming operation of the roll 7 (item F).

[0062] This arrangement of operations allows the transport ring 9 to be used to hold the tubular part 16 during the rolling operation of the roll 7, and also during the subsequent thread forming operation of the 8.

[0063] Without being exhaustive, and independently of each other, the following forming operations are applied to the following respective heights: a downstream band 162 of 3 to 7 mm, an intermediate band 163 of 10 to 25 mm, and an upstream band 164 of 5 to 15 mm.

[0064] Preferably, the manufacturing process may further include a step of placing a metal cap C onto the threaded neck 3 ( figure 3 ).

[0065] This operation is carried out using a technique that is classic in itself.

[0066] Capsule C is secured to this threaded neck 3 by a rotating capping head R.

[0067] For example, the rotating capping head R performs three simultaneous operations: The central tip of the rotating capping head R, by applying an axial load on the capsule C, compresses the seal C2 on the upper part of the roll 7 of the metal packaging 1 and re-stamped the upper corner of the capsule C to apply the seal C2 on the outer face of the roll 7, rollers rotating around the skirt C3 of the capsule C apply an axial force which pushes the metal of the skirt C3 into the hollows of the thread 8, thus creating the thread of the skirt C3, and rollers rotating around the tamper-evident ring C4 crimp it under the salient of the counter tamper-evident ring 10.

[0068] At the end of the manufacturing process, a bottle-shaped metal container 1 is obtained, as illustrated in the following: figures 1 to 3 . Localized annealing stage

[0069] The manufacturing process according to the invention includes, prior at least to the rolling operation of the roll 7, a localized annealing step (also called "Annealing " which is performed to impart an annealed state to the tubular part 16 at least over the height of the downstream band 162 of the tubular part 16 (illustrated very schematically by item B of the figure 4 ).

[0070] In other words, the localized annealing step is advantageously executed so that the tubular part 16 has an annealed state which is variable over its height.

[0071] In other words, the tubular part 16 advantageously presents, over its height, an annealing gradient.

[0072] Preferably, the localized annealing step is carried out to confer an annealed state only on the tubular part 16, at least over the height of the downstream band 162 of the tubular part 16.

[0073] In other words, only the tubular part 16 is in an annealed state, at least over the height of the downstream band 162 of the tubular part 16. The body 2 and / or the shoulder 4 are advantageously in an unannealed state.

[0074] According to the invention, the localized annealing step is advantageously performed to impart an annealed state: only at the level of the downstream band 162 (intended to form the roll 7), only at the level of the downstream band 162 and the upstream band 164 (intended to form respectively the roll 7 and the transport ring 9), so as to keep at least part of the height of the intermediate band 163 in an unannealed state to give the thread 8 optimal mechanical resistance qualities, or according to a variant which is not part of the invention at the level of the downstream band 162, the intermediate band 163 and the upstream band 164, or even over the entire height of the tubular part 16 intended to form the threaded neck.

[0075] Such a localized annealing step has the advantage of modifying the material's properties, elastic limit, ductility and elongation at break, giving malleability to the material constituting the tubular part 16.

[0076] The annealing step thus enables the forming of the threaded neck 3, allowing a reduction in the thickness of the body of the metal packaging 1 while preserving resistance to capping forces.

[0077] For example, the one-piece metal wall 5 has a thickness ranging from 0.2 to 0.5 mm.

[0078] Preferably, the annealing step is applied before the forming step of the tubular part 16 (i.e. before forming the different one-piece structures 7, 8, 9 and 10 of the threaded neck 3 within the superimposed bands 162, 163, 164, 165 of the tubular part 16).

[0079] Preferably, the localized annealing step is carried out to give an annealed state over a height of at least 3 to 7 mm to the downstream band 162 of the tubular part 16, starting from the downstream edge 161.

[0080] Similarly, the localized annealing step is advantageously executed to confer an annealed state on the height of the upstream strip 164 of said tubular part 16, advantageously on a height of 5 to 15 mm.

[0081] As developed below, the localized annealing step is advantageously implemented on a primary preform 15a comprising a tubular wall 18 of which a downstream section 181 is intended to undergo shrinking to form the tubular part 16 of the preform 15.

[0082] The implementation of this localized annealing step on this downstream section 181, and then shrinking this downstream section 181, has the advantage of conferring interesting mechanical properties for the forming operations of the tubular part 16 (advantageously, the mechanical work in shrinking restores part of the work hardening).

[0083] In general, but not part of the invention, the localized annealing step can be implemented to bring other parts of the preform 15, 15a into an annealed state, for example the body 2 or the shoulder 3 to facilitate their forming.

[0084] In general, in this localized annealing step, the metal of the preform 15, 15a is advantageously subjected to a high temperature, generally in the range of 150 to 450°C, such as 200 to 400°C and preferably even 200 to 350°C.

[0085] Annealing is carried out at an appropriate temperature for an appropriate period of time to achieve the desired reduction in yield strength and improvement in ductility and elongation at break.

[0086] Generally, for aluminum, the temperature is between 200°C and 400°C.

[0087] For high-temperature annealing, the annealing temperature is higher, for example 350°C to 454°C for a duration of 1 µs (microsecond) to 1 h (hour), for example 0.1 s (second) to 30 min (minutes), 1 s to 5 min or 10 s to 1 min.

[0088] For steel, the annealing temperature range is normally much higher and can be, for example, from 500°C to 950°C and the time period can be, for example, from 1 µs to 1 h, such as 0.1 s to 30 min, 1 s to 5 min, or 10 s to 1 min.

[0089] The annealing treatment results in a reduction of hardness, a reduction of yield strength and an increase in ductility.

[0090] In general, as illustrated on the figure 5 , the localized annealing step is implemented by an induction technique.

[0091] This induction technique is advantageously carried out within a tunnel inductor D, advantageously with rotation of the preforms 15, 15a.

[0092] This rotation is ensured for example by means of rotating M each preform 15, 15a around an axis of rotation parallel to its longitudinal axis (for example the longitudinal axis 18' of the tubular wall 18 described below).

[0093] The means for rotating M consist for example of a pair of lateral conveyor belts which have facing strands sandwiching the preforms 15, 15a and traveling at a relative speed appropriate to generate the rotation of the preforms 15, 15a during the localized annealing step.

[0094] Induction annealing is thus carried out by passing the preforms 15, 15a through the tunnel inductor D, with concentration of the magnetic field to advantageously obtain partial annealing of the areas of interest of the tubular wall 18 by thermal conduction and / or convection.

[0095] This approach advantageously reduces the loss of axial resistance of the thread 8, while improving the formability of the roll 7. Preform manufacturing stage

[0096] Prior to forming the tubular part 16 into a threaded neck 3, the preform manufacturing step advantageously includes: a deformation phase of a metal part (not shown) to obtain a primary preform 15a comprising a bottom 17 extended by a tubular wall 18 advantageously having a constant diameter over its height (see item A of the figure 4 ), a trimming phase, to form the downstream edge 161 of the primary preform 15a (item A of the figure 4 ), and a narrowing step, here of a downstream section 181 of the tubular wall 18, to form the tubular part 16 of a secondary preform 15, the tubular part 16 of which is connected to the body 2 by means of a shoulder 4 (items A and B of the figure 4 ).

[0097] The deformation phase is advantageously chosen from among the classic techniques in themselves, for example from stamping and / or drawing and / or reverse spinning.

[0098] In particular, stamping and / or drawing is preferably applied to a metal part consisting of a metal blank having, for example, a thickness ranging from 0.2 mm to 0.7 mm.

[0099] Stamping and / or drawing consist, for example, of a technique chosen from stamping / drawing (also called "Drawing and Wall Ironing" or DWI) or stamping and re-stamping (also called "Draw and Re Draw process" or DRD).

[0100] Reverse spinning is preferably applied from a pin of 2 to 15 mm.

[0101] Furthermore, according to the invention and as mentioned previously, the localized annealing step is advantageously applied prior to the forming step of the tubular part 16.

[0102] In this case, this annealing step is applied prior to the shrinking step, preferably between the trimming step and the shrinking step.

[0103] This annealing step is thus advantageously applied to the tubular wall 18 of the primary preform 15a (item A of the figure 4 ), before the restriction step (item B of the figure 4 ).

[0104] The localized annealing step is preferably applied to at least part of the height of the downstream section 181 of the tubular wall 18 (intended to form the tubular part 16), depending on the annealed / unannealed state which is expected at the level of the bands of the tubular part 16.

[0105] In particular, the localized annealing step is advantageously located at: only at the level of a downstream portion 182 corresponds, after narrowing, to the downstream band 162 (intended to form the roll 7), only at the level of a downstream portion 182 and an upstream portion 184 corresponds, after narrowing, respectively to the downstream band 162 and the upstream band 164 (intended to form respectively the roll 7 and the transport ring 9).

[0106] In general, the process also advantageously includes a varnishing phase of the preform 15, 15a, preferably an external varnishing phase and an internal varnishing phase.

[0107] This varnishing phase is preferably implemented after the localized annealing step, or even before the shrinking step (between items A and B of the figure 4 ).

[0108] The varnishing phase, which follows the localized annealing stage, helps to protect the varnish against thermal degradation. Forming operation / calibration of the transport ring

[0109] The present invention also relates to the forming, or even calibrating, operation of the transport ring 9.

[0110] The forming operation consists, for example, of a molding technique ( figures 6 And 7 ).

[0111] In this sense, the molding technique consists, for example, of applying internal pressure which causes the one-piece metal wall 5 to conform to the shape of a mold 20.

[0112] This internal pressure is exerted, for example, by: the compression of an elastomer 21 ( figure 6 ), or a pressurized fluid that is injected by means of an injection head 22 ( figure 7 ).

[0113] The molding technique may also involve using stretchable segments 23 ( figure 8 ).

[0114] The forming operation can also consist of a direct mechanical action by rotating an internal roller 24 on the internal face of the tubular part 16 while an external roller 25, opposite the first, holds the metal of the one-piece metal wall 5.

[0115] In this case, the internal wheel 24 preferably comprises a single rib 241; and the external wheel 25 comprises a pair of ribs 251, located on either side of the single rib 241.

[0116] In general, during the forming operation of the transport ring 9, an axial load F is advantageously exerted on the metal packaging 1, advantageously parallel to the longitudinal axis 16' of the tubular wall 16 ( Figure 10 ).

[0117] This approach has the advantage of accompanying the metal in its deformation and avoiding thinning and breakage phenomena.

[0118] This axial load is for example exerted by means of at least one support tool 28 which exerts an axial load on the tubular part 16 during the forming operation of the transport ring 9.

[0119] Said at least one tool 28 can exert an axial load for example at the downstream edge 161 of the tubular part 16 and / or at the bottom of the body 2 (opposite the tubular part 16, at the bottom 17).

[0120] Said at least one tool 28 can exert an axial load which is for example uniform over the whole circumference of the downstream edge 161 or localized on an area located on a generatrix passing through the area being formed of the transport ring 9.

[0121] This axial load is for example exerted by means of a support tool 28, for example in the shape of a crown, which exerts an axial load on the downstream edge 161 (towards the bottom 17 of the body 2).

[0122] According to yet another form of realization illustrated in figure 11 , the operation of forming the transport ring 9 may consist of an above and below shrinking technique of the tubular part 16.

[0123] For this purpose, for example, the following successive phases are implemented: an overlying shrinkage phase of the tubular part 16, to form the upper surface 92 of the transport ring 9 (items A and B of the figure 11 ), then an underlying shrinking phase, to form the lower surface 91 of the transport ring 9, for example by means of a pair of rollers 29 (items C and D of the figure 11 ).

[0124] Preferably, the forming operation of the transport ring 9 includes a further calibration phase to give the transport ring 9 its final shape.

[0125] This calibration operation is specifically intended to deform the lower 91 and upper 92 surfaces of the transport ring 9 to give it its final shape.

[0126] The calibration phase is carried out, for example: by pinching the annular deformation between two calibration rings 30, which are coaxial with the longitudinal axis 16' of the tubular part 16 and which are maneuvered according to an axial translation towards each other ( figure 12 ), or by two knobs 31 rotating around the tubular part 16 ( figure 13 ).

[0127] In particular, these calibration rings 30 and the rollers 31 are shaped / profiled / arranged to define, after deformation, the shape of the lower surfaces 91 and upper surfaces 92 of the transport ring 9.

[0128] Preferably, a 32 centering chuck (illustrated on the figure 12) is introduced into the tubular part 16 during calibration to ensure the concentricity of the parts above and below the tubular part 16 (on either side of the transport ring 9).

[0129] In practice, as illustrated on the figure 14 The calibration phase consists, for example: to bring the upper connecting radius 94 and the lower connecting radius 93 of the transport ring 9 into contact with each other, to ensure the optimal transfer of the axial force to the transport ring 9 during capping ( figure 14 ), and / or to bring the external radius 95 of the transport ring 9 to a minimum radius acceptable by the constituent material.

[0130] Alternatively, as illustrated on the figure 15, the upper connecting radius 94 and the lower connecting radius 93 of the transport ring 9 are radially offset from each other (while advantageously extending coaxially).

[0131] In this case, the diameter of the upper connecting radius 94 (in a plane perpendicular to the longitudinal axis 16') is advantageously less than the diameter of the lower connecting radius 93 (in a plane perpendicular to the longitudinal axis 16') of the transport ring 9.

[0132] The lower connecting radius 93 is advantageously supported against the upper surface 92 of the transport ring 9.

[0133] Such an embodiment provides a transport ring 9 whose upper surface 92 and lower surface 91 have different widths (the upper surface 92 is here wider than the lower surface 91).

[0134] This embodiment is obtained, for example, by a set of adapted knobs 29, similar to the figure 11 , for a technique of above and below narrowing of the tubular part 16 which is differential in diameter (whose above and below diameters of the tubular part 16 are different from each other; the above diameter is here less than the below diameter).

[0135] Of course, various other modifications can be made to the invention within the scope of the attached claims.

Claims

1. A method for manufacturing a bottle-shaped metal packaging, said metal packaging (1) having a body (2) connected to a threaded neck (3) through a shoulder (4), said method comprising: - a step of manufacturing a preform (15) including a tubular part (16), defining a longitudinal axis (16') and a free, downstream edge (161), wherein said tubular part (16) is connected to a body (2) through a shoulder (4), and - a step of forming said tubular part (16), to form said threaded neck (3), said forming step comprising forming operations suitable to form one-piece structures on said tubular part (16): - an operation of forming a roll (7) within a downstream strip (162) of said tubular part (16), ended by said downstream edge (161), to form a roll (7) at the downstream edge (161) of the threaded neck (3), - an operation of forming a thread (8) within an intermediate strip (163) of said tubular part (16), and - an operation of forming a transport ring (9) within an upstream strip (164) of said tubular part (16), on the shoulder (4) side, intended to cooperate with a handling device, characterized in that said manufacturing method comprises, prior to at least said roll (7) forming operation, preferably prior to said tubular part (16) forming step, a localised annealing step that is carried out in order to provide annealed state to the tubular part (16), at least over the height of the downstream strip (162) of said tubular part (16), said method being characterized in that the localised annealing step is executed to provide annealed state: - only at said downstream strip (162), or - only at the downstream strip (162) and the upstream strip (164), in such a way as to keep at least part of the height of the intermediate strip (163) in non-annealed state.

2. The method for manufacturing a bottle-shaped metal packaging (1) according to claim 1, characterized in that the localised annealing step is carried out in order to provide annealed state over a height of at least 3 to 7 mm of the downstream strip (162) of said tubular part (16).

3. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 or 2, characterized in that the localised annealing step is carried out in order to provide annealed state over the height of the upstream strip (164) of said tubular part (16), advantageously over a height of 5 to 15 mm.

4. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 3, characterized in that the preform (15) manufacturing step comprises: - a phase of deforming a metal part to obtain a primary preform (15a) having a bottom (17) extended by a tubular wall (18), - an edge trimming phase, to form the downstream edge (161) of said primary preform (15a), and - a necking step, to form said tubular part (16) of a secondary preform (15), and in that said localised annealing step is carried out on the tubular wall (18) of the primary preform (15a), before the necking step.

5. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 4, characterized in that the localised annealing step is carried out by an induction technique, advantageously within a tunnel inductor, advantageously with rotation of the preform (15).

6. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 5, characterized in that the transport ring (9) forming operation is implemented prior to the roll (7) forming operation, said transport ring (9) being advantageously used for holding the tubular part (16) during said roll (7) forming operation.

7. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 6, characterized in that the tubular part (16) forming step also comprises an operation of forming a pilfer-proof counter-ring (10) within an additional strip (165) of the tubular part (16), located between the intermediate strip (163) and the upstream strip (164), forming a pilfer-proof counter-ring groove (11) between said pilfer-proof counter-ring (10) and said transport ring (9).

8. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 7, characterized in that said method also comprises a varnishing phase, preferably an external varnishing phase and an internal varnishing phase implemented after the localised annealing step.

9. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 8, characterized in that said metal packaging (1) is made in a 3000 or 5000 series aluminium alloy, for example 3104 aluminium alloy.

10. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 10, characterized in that the transport ring (9) forming operation is selected among: - a moulding technique, or - a direct mechanical action using a movable tool, or - an overlying and underlying necking technique.

11. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 11, characterized in that the transport ring (9) forming operation comprises a calibration phase to give a definitive shape to said transport ring (9).

12. The method for manufacturing a bottle-shaped metal packaging (1) according to claim 12, characterized in that the calibration phase consists in: - bringing the upper connection radius (94) and the lower connection radius (93) of the transport ring (9) in contact with each other, or in obtaining an upper connection radius (94) and a lower connection radius (93) of the transport ring (9) that are radially offset with respect to each other, with said lower connection radius (93) advantageously in abutment against the upper surface (92) of the transport ring (9), and / or - bringing the external radius (95) of the transport ring (9) to a minimum radius acceptable to the constituent material.

13. The method for manufacturing a bottle-shaped metal packaging (1) according to any one of claims 1 to 12, characterized in that, during the transport ring (9) forming operation, an axial load is exerted on the metal packaging (1) to accompany the metal in its deformation and avoid thinning and breakage.

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