Method of forming a closure member

Abstract

NOT VISIBLE DUE TO STATUS OF PATENT

Description

[0001] TITLE: “Method of forming a closure member”

[0002] TECHNICAL FIELD

[0003] The present invention relates to a method of forming a closure member. In particular, the present invention relates to a method of forming a closure member by magnetic forming.

[0004] BACKGROUND OF THE INVENTION

[0005] Magnetic forming process is known in the state of art and has been employed in various applications.

[0006] In a magnetic forming process, a coil surrounds the workpiece, made of electrically conductive material, which is to be deformed, at a small distance. When an electric current flows through this coil, a magnetic field forms, which encloses the element to be deformed, and therein induces eddy currents in its surface, which in turn generate a second magnetic field with a direction opposite to the first, for which reason the two fields repel one another. Thereby, on the circumference of the workpiece, in the plane of the electric coil, a force develops which is oriented radially to the center point of the workpiece.

[0007] US 5,246,124 discloses a method of forming a closure by magnetic forming. This document discloses a closure for bottles comprising a pouring body and a cap releasably engaged with the pouring body. The cap is attached to a tubular outer skirt abutting an annular outer portion of a collar attached with the pouring body. The skirt and the annular outer portion are interconnected by a frangible outer ring binding the skirt and the annular outer portion of the collar together. An outer metallic band is fitted around the outer ring in close contact therewith. The outer metallic band is set tightly around the outer ring by magnetic forming process.

[0008] The magnetic forming process is carried out by generating a quickly varying, high-energy magnetic field, e.g. by the supply of a high-current pulse through suitable leads arranged to induce a current through the band.

[0009] The energy transferred to the band by interaction between the induced current and the magnetic field is of such a level as to create a force which causes the band to shrink radially and set tightly around the outer surface of the outer ring.

[0010] The closure is assembled by mounting all the components together and finally setting the band around the ring by magnetic forming. The closure so assembled is ready to be mounted on a neck of a bottle.

[0011] US 5,246,124 therefore discloses the use of magnetic forming process to form a metallic band on a plastic ring of a closure.

[0012] Different applications of the magnetic forming are disclosed in US 2010 / 275439 and WO 2014 / 090902.

[0013] US 2010 / 275439 discloses a method for sealing containers with a metal cap by magnetic forming by a multiple tube processing coil.

[0014] WO 2014 / 090902 discloses a method of assembling a cover with a container.

[0015] WO 2017 / 108611 discloses a method of forming a closure to be subsequently applied on a container neck or a closure body. Forming of the closure is obtained by application of a magnetic field on a member comprising a first member made of electrically conductive material and a second member made of insulating material inserted at least in part within the first member. The magnetic field deforms at least a portion the first member in form of sleeve on the second member.

[0016] The magnetic forming methods disclosed by the above cited prior art references have drawbacks related to the employed energy for the deformation, the damages on the second member upon the deformation and the overheating of the components related to the magnetic field generation.

[0017] Namely, the deformation of the first member causes an approaching of the first member to the second member to cover a standard gap defined between the second member and the first member. The speed of deformation of first member reached along the standard gap causes an energy release on the second member at the impact. Such release, in the form of a hit, damages the second member for example frangible portions and / or weakened portions, thereby breaking them. Furthermore, the energy needed for approaching the first member by magnetic field increases as a function of the gap. Consequently, such gaps cause an overheating of the magnetic field generation apparatus causing damages and downtime to the apparatus.

[0018] Therefore, the magnetic forming methods disclosed by the above cited prior art references are not suitable to form closure members to be subsequently applied on a container neck or a closure body, in series and with a high rate of production.

[0019] Moreover, the applicant noted that, during application of magnetic field, air may remain trapped into the gap between the first member and the second member. Once application of magnetic field is completed, this air trapped into the gap may slightly push outwardly portions of the first member, thereby damaging the deformation expected on the first member which does not reproduce, as desired, the contour of the second member.

[0020] SUMMARY OF THE INVENTION

[0021] The object of the present invention is to provide a method of forming a closure member with any shape for subsequently applying the formed closure member on a container neck or a closure body. The present invention relates to a method of forming a closure member, the method comprising the steps of: a) providing a member comprising:

[0022] - a first member made of electrically conductive material, said first member comprising a tubular sleeve extending along a longitudinal direction between a first top end and a first bottom end,

[0023] - a second member made of electrically insulating material and arranged inside the first member, said second member comprising a second top wall and a second tubular sleeve extending from the second top wall to a second bottom end, a first annular gap being defined between the first tubular sleeve and the second tubular sleeve; b) applying a mechanical action on the first tubular sleeve towards the second tubular sleeve to define a pre-shaped member having a second annular gap between the first tubular sleeve and the second tubular sleeve smaller than the first annular gap; c) providing a support member with an outer support surface, d) positioning the pre-shaped member on the support member, e) applying a magnetic field on the pre-shaped member to deform at least a portion of the first tubular sleeve around the second tubular sleeve to form a closure member, f) removing the formed closure member from the support member, wherein, in step b), the mechanical action is carried out by a shaping member configured to act on a first outer tubular surface of the first tubular sleeve by a mutual rotation of at least a portion of the shaping member and the member.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS The characteristics and advantages of the present invention will appear from the following detailed description of one practical embodiment, which is given as a not limiting example with reference to the annexed drawings, in which:

[0025] - FIG. 1 shows a section view of the member in a first configuration wherein the first tubular sleeve and the second tubular sleeve are at first distance along the longitudinal extension;

[0026] - FIG. 2 shows a section view of the member in a second configuration wherein the first tubular sleeve and the second tubular sleeve are at second distance along the longitudinal extension smaller than the first distance;

[0027] - FIG. 3 a first embodiment of an apparatus for carrying out the method of the present invention with a member to be formed of FIG.2,

[0028] - FIG. 4 shows the embodiment of FIG.3 with the formed closure;

[0029] - FIG.5 shows the block diagram of the steps of the method according to one embodiment of the present invention;

[0030] - FIG.6 shows a schematic perspective view of a shaping member with some components omitted for better showing others according to one embodiment of the present invention.

[0031] DETAILED DESCRIPTION

[0032] Referring to the figures 1-4, there is shown a closure member 1 formed according to one embodiment of the method of the present invention.

[0033] The closure member 1 is configured to be fitted directly on a neck of a container or a closure body.

[0034] The term “neck” in connection with a container having a container body may refer to a neck made as one piece element with the container body or to a pouring body firmly attached to the neck made as one piece with the container body.

[0035] The term "closure body" refers to any part of a closure such a threaded cap, a hinged lid cap or flip top cap, a push-on cap, a pourer and the like.

[0036] If the closure member 1 is configured to be fitted directly on a neck of a container, the closure member 1 may be provided with attachment members configured to engage with attachment members formed on the neck to attach the closure member 1 to the neck. Alternatively, the closure member 1 may be attached to the neck by deforming a part of the closure member 1, mechanically or magnetically, for example as disclosed in US 2010 / 275439 or WO 2014 / 090902.

[0037] The method comprises the step a) of providing a member 20.

[0038] According to one embodiment, the member 20 comprises a first member 30 made of electrically conductive material, preferably aluminium.

[0039] Preferably the first member 30 is made of sheet material, more preferably with thickness between 0.2 mm and 0.3 mm, still more preferably with thickness between 0.21 and 0.25 mm, still more preferably with a thickness of 0.23 mm.

[0040] According to the embodiment shown in the figures, the first member 30 is shaped as a capsule closed on top and open on the bottom.

[0041] The first member 30 extends along a longitudinal direction X-X between a first top end 33’ and a first bottom end 33. The first member 30 further comprises a first tubular sleeve 32 extending along the longitudinal direction X-X between the first top end 33’ and the first bottom end 33.

[0042] The first bottom end 33 defines a bottom opening 38 of the first member 30.

[0043] The first member 30 has a first inner surface 35 and a first outer surface 36.

[0044] The first tubular wall 32 has a first inner tubular surface 32a and a first outer tubular surface 32b. According to one embodiment, the first member 30 has a first top wall 31. The first tubular sleeve 32 extends along the longitudinal direction X-X between the first top wall 31 and the first bottom end 33.

[0045] Therefore, the first tubular sleeve 32 is closed on top by the first top wall 31 and has the bottom opening 38 on the bottom.

[0046] The first top wall 31 has a first inner top surface 31a and a first outer top surface 31b.

[0047] The first inner surface 35 comprises the first inner top surface 31a and the first inner tubular surface 32a.

[0048] The first outer surface 36 comprises the first outer top surface 3 lb and the first outer tubular surface 32b.

[0049] Alternatively, the first member 30 may be a tubular sleeve open on top and bottom and for example defined only by the first tubular sleeve 32 extending longitudinally between a first top end 33’, where the first top wall 31 is provided, and the first bottom end 33.

[0050] The member 20 further comprises a second member 40 made of electrically insulating material, preferably plastic material. Preferably, the second member 40 comprises a second top wall 41 and a second tubular sleeve 42 extending from the second top wall 41 to a second bottom end 43 along the longitudinal direction X-X.

[0051] The second member 40 is arranged inside the first member 30.

[0052] In the example shown in the attached figures, the second member 40 is a threaded cap. However, the second member 40 may be a hinged lid cap or flip top cap, a push-on cap, a pourer and the like. When the second member 40 is a hinged lid cap or a pourer, the first member 30 may not be closed on top and may be a tubular sleeve open on top and bottom. The second bottom end 43 defines a bottom opening 43 a of the second member 30. Therefore, the second tubular sleeve 42 is closed on top by the second top wall 41 and has the bottom opening 43a on the bottom.

[0053] The second member 40 has a second inner surface 45 and a second outer surface 46.

[0054] The second top wall 41 has a second inner top surface 41a and a second outer top surface 41b.

[0055] The second tubular wall 42 has a second inner tubular surface 42a and a second outer tubular surface 42b.

[0056] The second inner surface 45 comprises the second inner top surface 41a and the second inner tubular surface 42a.

[0057] The second outer surface 46 comprises the second outer top surface 42a and the second outer tubular surface 42b.

[0058] In the step a) a first annular gap G1 is defined between the first tubular sleeve 32 and the second tubular sleeve 42. Namely, the first annular gap G1 extends longitudinally along a mutually overlapping portion of the first tubular sleeve 32 and the second tubular sleeve 42. Such first annular gap G1 can be constant or variable along longitudinal direction X-X as a function of the shape of the first member 30 and / or the second member 40.

[0059] Preferably, the first annular gap G1 is defined between the first inner tubular surface 32a and the second outer tubular surface 42b for the overlapping portion. More preferably, the first annular gap G1 extends radially between the first tubular sleeve 32 and the second tubular sleeve 42 and longitudinally along the longitudinal direction

[0060] X-X for at least a portion of the extension of the first tubular sleeve 32.

[0061] More preferably, the first annular gap G1 represents, along the longitudinal direction X-X, the distances, in terms of radial extension, between the first inner tubular surface 32a and the second outer tubular surface 42b along the overlapping portion of the first tubular sleeve 32 and the second tubular sleeve 42. Such distances are measured along a spacing direction Y-Y perpendicular to the longitudinal direction X-X and perpendicular to the first inner tubular surface 32a and second outer tubular surface 42b.

[0062] The method comprises the step b) of applying a mechanical action on the first tubular sleeve 32 towards the second tubular sleeve 42 to define a pre-shaped member 20’ as shown in figure 2. The pre-shaped member 20’ has a second annular gap G2, between the first tubular sleeve 32 and the second tubular sleeve 42, smaller than the first annular gap G1. Preferably, the second annular gap G2 extends radially between the first tubular sleeve 32 and the second tubular sleeve 42 and longitudinally along a mutually overlapping portion of the first tubular sleeve 32 and the second tubular sleeve 42. It is to be noted that, as for first annular gap Gl, the second annular gap G2 is defined between the first inner tubular surface 32a and the second outer tubular surface 42b for the overlapping portion. Namely, the second annular gap G2 represents, along the longitudinal direction X-X, the distances, in terms of radial extension, between the first inner tubular surface 32a and the second outer tubular surface 42b along the overlapping portion of the first tubular sleeve 32 and the second tubular sleeve 42 after the step b). Such distances are measured along the spacing direction Y-Y.

[0063] Hereinafter, for sake of simplicity, the same references used for the first member 30 and the second member 40 of the member 20 are referred to for the preshaped member 20’.

[0064] According to a preferred embodiment, the step b) provides a radial approach of the first tubular sleeve 32 towards the second tubular sleeve 42 passing from the first annular gap G1 having a first radial extension to the second annular gap G2 having a second radial extension smaller than the first radial extension. In this way, the step b) provides a reduction of the space between the first tubular sleeve 32 and the second tubular sleeve 42.

[0065] Preferably, in step b) the mechanical action is carried out by a shaping member 90 configured to act on the first outer tubular surface 32b of first tubular sleeve 32 by a mutual rotation of at least a portion of the shaping member 90 and the member 20.

[0066] More preferably, the shaping member 90 has a variable profile along the longitudinal direction X-X configured to progressively act on the first outer tubular surface 32b from the first top end 33’ to the first bottom end 33 during the mutual rotation. By this way, the first tubular sleeve 32 approaches radially to the second tubular sleeve 42, progressively along the longitudinal direction X-X.

[0067] Namely, the shaping member 90 comprises a central body 91 extending along the longitudinal direction X-X from a top end portion to the bottom end portion following the extension of the member 20. The central tubular body 91 has an outer surface 91a which defines the variable profile and configured to act on first tubular sleeve 32. The outer surface 91a has variable recesses along the spacing direction Y- Y tapered from the top end portion towards the bottom end portion.

[0068] In the mutual rotation of the member 20 and the at least a portion of the shaping member 90, the variable profile of the shaping member 90 allows to act on circumferential consecutive portions of the first outer tubular surface 32a progressively urging the first outer tubular surface 32a along the longitudinal direction X-X towards the first bottom end 33. In this way, the air in the first annular gap G1 is progressively ejected from the top end 33’. The progressive approach of the first tubular sleeve 32 to the second tubular sleeve 42 strongly reduces or avoids the risk that air remains trapped within the first tubular gap Gl. By this way, the degree of variations of the shape of the first tubular sleeve 32 copied on the second tubular sleeve 42 can be improved.

[0069] According to one embodiment shown in figure 6, one or more members 20 are arranged on a rotatable pre-shaping support member 92. Namely, the pre-shaping support member 92 is configured to rotate about the longitudinal direction X-X (according to the relative arrow shown in figure 6) with respect to the central tubular body 91. The shaping member 90 comprises one or more pre-shaping retaining assemblies 93 arranged on the pre-shaping support member 92. Each pre-shaping retaining assembly 93 is configured to rotatably retain a relative member 20 allowing the rotation of members 20 around the longitudinal direction X-X (according to the relative arrows on the members 20 shown in figure 6). The central tubular body 91 is configured to act on each second member 40 during the rotation of the pre-shaping support member 92. The rotation of the pre-shaping support member 92 and the action of the central tubular body 91 on each second member 40 cause a drag rotation of each member 20 retained by pre-shaping retaining assemblies 93.

[0070] Thanks to the mutual rotation of each member 20 and of the pre-shaping support member 92, the pre-shaped member 20’ is obtained.

[0071] Alternatively, the member 20 is mounted on a fixed pre-shaping support member and the shaping member rotates around the member 20.

[0072] The method comprises the step c) of providing a support member 10. The support member 10 has an outer support surface 11. Preferably, the support member 10 extends along the longitudinal direction X-X and has a support axis extending along the longitudinal direction X-X. According to one embodiment, the support member 10 comprises a male element 12 and a stem 13 positioned inside the male element 12. Preferably, the male element 12 comprises a base 14 and a lateral wall 15 circumferentially projecting longitudinally from the base 14 to a top support wall 16. The lateral wall 15 is configured to engage the second inner tubular surface 42b and the second inner top surface 41b.

[0073] The method comprises the step d) of positioning the pre-shaped member 20’ on the support member 10. In this way, the first inner surface 35 of the first member 30 faces the outer support surface 11 of the support member 10.

[0074] According to one embodiment, after the positioning of the pre-shaped member 20’ on the support member 10, the step d) comprises a sub step of generating vacuum / a depressurization between the support member 10 and the second member 40. This prevents longitudinal, transversal and rotation movements of the second member 40 with respect to the support member 10 during step e).

[0075] Preferably, the depressurization is a depressurization between 0.1 bar and 0.8 bar, preferably 0.2 bar.

[0076] Namely, the support member 10 is configured to prevent movements of the second member 40 during step e). The support member 10 is configured to retain the second member 40 acting on the second inner tubular surface 42a of the second member 40.

[0077] According to one embodiment, the support member 10 comprises a plurality of radial depressurizing channels 81 within the support member 10, preferably extending from the stem 13. The radial depressurizing channels 81 radially extend from a central depressurizing channel 80 connected to a vacuum pump (not shown in the figures) provided within the stem 13. The support member 10 can comprise one or more longitudinal depressurizing channels 82 extending along the longitudinal direction X-X and extending from the central depressurizing channel 80.

[0078] Each radial depressurizing channel 81 and each longitudinal depressurizing channel 82 have a depressurizing port 81a, 82a facing the member 20. Namely, the depressurizing ports 81a, 82a are formed on the lateral wall 15. Preferably, the depressurizing ports 81a related to the radial depressurizing channels 81 are the spaced circumferentially and define longitudinally spaced groups, while depressurizing ports 82a related to the longitudinal depressurizing channel 82 are spaced apart along an upper wall 16 of the support member 10.

[0079] Each depressurizing port 81a, 82a directly communicates with the second inner tubular surface 42a.

[0080] Preferably, for each depressurizing port 81a, 82a, a sealing member is provided to seal between the second inner tubular surface 42a and outer surface 11 of the support member 10 at the depressurizing ports 81a, 82a. In this way, the depressurizing of the channels 81, 82 sucking air between the second inner tubular surface 42a and outer surface 11 of the support member 10 allows to firmly retain the second member 40.

[0081] The method comprises the step e) of applying a magnetic field on the preshaped member 20’ to deform at least a portion of the first tubular sleeve 32 around the second tubular sleeve 42 to form a closure member 1.

[0082] Preferably, an induction coil 50 is arranged closely around the pre-shaped member 20’ to entirely surround the pre-shaped member 20’. The induction coil 50 is powered and controlled by an electric power generation and control unit (not shown in the figures) to generate a magnetic field, in particular a pulsed magnetic field that generates a pulsed magnetic force on the member 30.

[0083] Preferably the pulsed magnetic field has a width of 10 ps and a cycle of 1 pulse per 5 seconds.

[0084] This magnetic field generated by the induction coil 50 is applied to the member 30 to deform the first tubular sleeve 32 of the first member 30 around the overlapping portion on the second member 20 to form the closure member 1.

[0085] In particular the magnetic field bends the first member 30 in a radially inward direction around the second member 40 more particularly around the second outer tubular surface 42b of the second member 40.

[0086] According to one embodiment, the induction coil 50 comprises a coil 51 configured to generate the magnetic field and surrounding the pre-shaped member 20’. Preferably, the induction coil 50 further comprises one or more spacing elements 52 arranged between the pre-shaped member 20’ and the coil 51 to surround the preshaped member 20’. More preferably, the one or more spacing elements 52 comprise electrically insulating material arranged inside each spacing element 52.

[0087] In the step e) at least a portion of the first tubular sleeve 32, preferably all first tubular sleeve 32, is deformed directly against the second tubular sleeve 42 so that the deformed portion of the first tubular sleeve 32 is shaped as the second outer tubular surface 42b. This means that the deformed portion of the tubular sleeve 32 follows the shape of the second outer tubular surface 42b.

[0088] Preferably, the first tubular sleeve 32 deforms directly against the second tubular sleeve 42 of second member 40, namely along the mutually overlapping portion of the first tubular sleeve 32 on the second tubular sleeve 42.

[0089] The method comprises the step f) of removing the formed closure member 1 from the support member 10. According to one embodiment, the formed closure member 1 is removed from the support member 10 for subsequently fitting it on a neck of a container or a closure body. According to one embodiment, the second tubular sleeve 42 comprises along the longitudinal direction X-X from the top wall 41 to bottom end 43 one or more weakened portions 100.

[0090] In these weakened portions 100, circumferentially spaced full portions and circumferentially spaced void portions adjacent to full portions can be defined such that the full portions and the void portions are arranged circumferentially in alternate arrangement. Such full and void portions define the frangible portions connecting an upper part of the second tubular sleeve 42 with a lower part of the second tubular sleeve 42. Accordingly, at the frangible portions, the first tubular sleeve 32 is machined in a manner known in the state of art to define relative frangible portions on the first tubular sleeve 32.

[0091] Alternatively, or in combination with the frangible portions, the weakened portions can comprise a thickness smaller than the thickness of the remaining second tubular sleeve 42. Such smaller thickness portion defines a tamper evident element.

[0092] According to one embodiment, the method further comprises, before the step e), a step d’) of softening the second member 40 by heating the second member 40. Preferably, the step d’) is carried out by a heating member which is configured to act on the second member 40 for softening it before the subsequent steps. In this way, the weakened portions are softened and ready for the further steps preventing relative damages.

Claims

CLAIMS1. A method of forming a closure member (1), the method comprising the steps of: a) providing a member (20) comprising:- a first member (30) made of electrically conductive material, said first member (30) comprising a first tubular sleeve (32) extending along a longitudinal direction (X-X) between a first top end (33’) and a first bottom end (33),- a second member (40) made of electrically insulating material and arranged inside the first member (30), said second member (40) comprising a second top wall (41) and a second tubular sleeve (42) extending from the second top wall (41) to a second bottom end (43), a first annular gap (Gl) being defined between the first tubular sleeve (32) and the second tubular sleeve (42); b) applying a mechanical action on the first tubular sleeve (32) towards the second tubular sleeve (42) to define a pre-shaped member (20’) having a second annular gap (G2) between the first tubular sleeve (32) and the second tubular sleeve (42) smaller than the first annular gap (Gl); c) providing a support member (10) with an outer support surface (11), d) positioning the pre-shaped member (20’) on the support member (10), e) applying a magnetic field on the pre-shaped member (20’) to deform at least a portion of the first tubular sleeve (32) around the second tubular sleeve (42) to form a closure member (1), f) removing the formed closure member (1) from the support member (10), wherein, in step b), the mechanical action is carried out by a shaping member (90) configured to act on a first outer tubular surface (32b) of the first tubular sleeve (32) by a mutual rotation of at least a portion of the shaping member (90) and the member2. The method according to claim 1, wherein the shaping member (90) has a variable profile along the longitudinal direction (X-X) configured to progressively act on the first outer tubular surface (32b) from the first top end (33’) and to the first bottom end (33) during the mutual rotation of the at least a portion of the shaping member (90) and the member (20).

3. The method according to claim 1 or 2, wherein:- the first annular gap (Gl) extends radially between the first tubular sleeve (32) and the second tubular sleeve (42) and longitudinally along a mutually overlapping portion of the first tubular sleeve (32) and the second tubular sleeve (42);- the second annular gap (G2) extends radially between the first tubular sleeve (32) and the second tubular sleeve (42) and longitudinally along a mutually overlapping portion of the first tubular sleeve (32) and the second tubular sleeve (42);- the step b) provides a radial approach of the first tubular sleeve (32) towards the second tubular sleeve (42) passing from the first annular gap (Gl) having a first radial extension to the second annular gap (G2) having a second radial extension smaller than the first radial extension.

4. The method according to any claims 1 to 3, wherein in the step e):- at least a portion of the first tubular sleeve (32) is deformed directly against the second tubular sleeve (42).

5. The method according to any claims 1 to 4, further comprises, before the step e), a step d’) of- softening the second member (40) by heating the second member (40).

6. The method according to any of claims 1 to 5, wherein:- said first member (30) comprises a first top wall (31), - said first tubular sleeve (32) extending along said longitudinal direction (X-X) between said first top wall (31) and said first bottom end (33).

7. The method according to any of claims 1 to 6, wherein the magnetic field in step e) is generated by an induction coil (50) arranged around the pre-shaped member (20’) to entirely surround the pre-shaped member (20’), the induction coil (50) comprising:- a coil (51) configured to generate the magnetic field and surrounding the preshaped member (20’);- one or more spacing elements (52) arranged between the member (20) and the coil (51) to surround the pre-shaped member (20’).

8. The method according to claim 7, wherein the one or more spacing elements (52) comprise electrically insulating material arranged inside each spacing element (52).