CAN SUPPORT MEMBER, AND METHOD AND APPARATUS FOR MANUFACTURING SEAMLESS CAN

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Rule 53(b) Continuation of International Application No. PCT/JP2024/020899 filed on June 7, 2024, claiming priority based on Japanese Patent Application No. 2023-109509 filed on July 3, 2023, the respective disclosures of all of which are incorporated herein by reference in their entirety.

The disclosure relates to a support member for a can body used in a can manufacturing process, and more particularly, to a can support member capable of supporting and fixing a can body without causing deformation of the can body in a necking process during manufacture of a seamless can, and a manufacturing method and a manufacturing apparatus using the can support member.

BACKGROUND

Seamless cans (DI cans), which are molded by drawing and ironing or the like, are widely used as can bodies for storing beverages and food. In such seamless cans, the can barrel portion is required to be thinned for resource saving and weight reduction. In the case of general 350 ml seamless cans for carbonated beverages, the plate thickness of the aluminum alloy material is 0.26 mm or less in most cases. In seamless cans obtained by drawing and ironing such a thin metal plate, the pressure resistance strength of the bottom portion is particularly likely to decrease, and therefore, various proposals have been made for the shape of the can bottom portion in order to ensure higher pressure resistance strength.

For example, JP 2018-177289 A below discloses a seamless can including a bottom portion and a thin-walled barrel portion, in which the bottom portion includes a dome portion bulging upward and located at a central portion of the bottom portion, a ground contact portion descending from a peripheral edge of the dome portion, and a chime portion extending outward and upward in an inclined manner from the ground contact portion and continuous with a lower end of the barrel portion.

In addition, JP 2016-043991 A below discloses a seamless can in which, in order to enhance the pressure resistance strength of the thinned bottom portion, an inner peripheral wall continuous with a dome portion is formed with a first concave curved surface portion having a curved shape recessed outward in a radial direction orthogonal to a can axis, and the dome portion is formed with a dome top located on the can axis, a second concave curved surface portion having a concave curved shape connected to an outer side of the dome top in the radial direction and having a smaller radius of curvature than that of the dome top, and a tapered portion arranged on an outer peripheral edge portion of the dome portion, connecting the first concave curved surface portion and the second concave curved surface portion, and having a linear shape contacting the first concave curved surface portion and the second concave curved surface portion.

On the other hand, also in the seamless can formed by drawing and ironing a thin metal sheet as described above, a diameter of the neck portion is reduced by necking the can body after drawing and ironing, and in this case, it is proposed to use a container support body movable in the can axial direction with respect to a die for forming a neck, and to perform the processing by moving the container support body, as disclosed in JP 2000-503260 T below.

SUMMARY

However, in an industrial can manufacturing process, particularly in necking processing, the upper portion of the can body is pushed into a necking tool to perform the processing, and therefore, a large compressive load is applied to the can body in the can axial direction. Therefore, in the thin-walled can body having the chime portion as described in JP 2018-177289 A, the chime portion not supported by the support member may be buckled and deformed by the axial load applied to the ground contact portion, and particularly in the seamless can in which the shape of the inner peripheral wall of the annular protrusion is adjusted by the bottom reforming processing as described in JP 2016-043991 A, the outer peripheral wall (chime portion) is also formed as a gently concave curved surface, and deformation due to the necking processing is more likely to occur.

Accordingly, an object of the disclosure is to provide a support member capable of supporting and fixing a can body without causing deformation of a chime portion when forming a seamless can having the chime portion.

Another object of the disclosure is to provide a method and an apparatus for manufacturing a thin-walled seamless can without causing a molding defect.

According to the disclosure, there is provided a can support member for supporting and fixing a can body in a can manufacturing process, wherein the can body is a seamless can having a barrel portion and a bottom portion, the bottom portion has a bottom shape including at least a ground contact portion and a tapered chime portion continuous from the ground contact portion to a lower end of the barrel portion and having an outer diameter increasing upward in a can axial direction, and the ground contact portion and the chime portion are supported from outside the can.

In the can support member of the disclosure, preferably,

(1) a can support portion including a holding portion contacting the ground contact portion and receiving the bottom portion, and an annular sidewall extending from a peripheral edge portion of the holding portion and having an inner surface contacting the chime portion, and a movable shaft configured to move the can support portion in the can axial direction are provided,

(2) the annular sidewall is formed with a plurality of slits extending in the can axial direction from an upper end to a lower end of the annular sidewall, and a stripper wheel is provided with strippers configured to separate the can body from the can support portion without interfering with the slits, and

(3) the can body includes a dome portion protruding inward of the can at a center of the bottom portion, and an inner peripheral wall extending downward in the can axial direction from an outer peripheral edge of the dome portion and curved inward in a can radial direction, and the ground contact portion is located at a lower end of the inner peripheral wall and a lower end of the chime portion.

According to the disclosure, there is also provided a method for manufacturing a seamless can, the method including at least can body forming and necking, wherein in the necking, necking processing is performed in a state where a ground contact portion and a chime portion of a can bottom portion are supported and fixed from outside a can by a can support member.

In the method for manufacturing a seamless can of the disclosure, preferably, the method further includes bottom reforming before the necking, and in the bottom reforming, a pressing body is inserted into a can body, and a bottom portion of the can body is pressed by the pressing body and a molding die installed on an outer surface side of the can body, thereby curving an inner peripheral wall inward in a can radial direction to form an annular curved end portion having a ground contact portion.

According to the disclosure, there is also provided an apparatus for manufacturing a seamless can, the apparatus including at least a can body molding means, a necking means, and a conveying means configured to connect the can body molding means and the necking means, wherein the necking means includes a can support member capable of supporting and fixing a can bottom of a can body conveyed from the conveying means, and the can support member is a can support member capable of supporting and fixing a ground contact portion and a chime portion of a can bottom portion from outside a can.

Since the can support member of the disclosure includes the holding portion and annular sidewall matching a bottom shape of the can body, the bottom portion of the can body can be supported not only in the axial direction but also in the horizontal direction from the outside, and the processing in the necking can be reliably performed. In addition, the inner surface of the annular sidewall that contacts the chime portion of the can bottom portion has a shape matching the chime portion. Therefore, even when the can body is pushed into the necking tool by pressing the can bottom in the can axial direction in the necking processing, the chime portion that is thin and likely to be deformed is pressed while being supported by the inner surface of the annular sidewall, and thus the deformation is effectively prevented.

Additionally, the annular sidewall of the can support member is formed with the plurality of slits, and the stripper wheel is provided with the strippers that do not interfere with the slits. Thus, the strippers are moved relatively in the slits and the upper ends of the strippers are located at the same positions as or above the upper end of the annular sidewall, so that the can body can be easily separated from the can support member.

Further, in the method and apparatus for manufacturing a seamless can using the can support member of the disclosure, the necking processing is performed in a state where the can body is supported and fixed by the can support member without displacement of the ground contact portion and the chime portion of the can bottom portion in the axial direction and the horizontal direction from outside the can, and thus the necking processing can be efficiently and reliably performed. Additionally, the strippers are relatively moved in the slits, and the upper ends of the strippers are located at the same positions as or above the upper end of the annular sidewall, so that, after the can body is separated from the can support member, the interference of the annular sidewall portion in the advancing direction of the can body is eliminated, and therefore, the can body can be smoothly conveyed to the next step.

Furthermore, even in a seamless can subjected to the bottom reforming processing, deformation of the chime portion can be effectively prevented by using the can support member of the disclosure.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1A and 1B are diagrams for illustrating an example of a can support member of the disclosure, in which FIG. 1A is a side cross-sectional view illustrating a state of supporting a can bottom portion, and FIG. 1B is a perspective view.

FIGS. 2A, 2B, 2C, and 2D are diagrams for illustrating an operation of the can support member of the disclosure.

FIG. 3 is a partial perspective view for illustrating an example of a necking step in an apparatus for manufacturing a seamless can of the disclosure.

DESCRIPTION OF EMBODIMENTS

Can Support Member

A can support member of the disclosure will be described with reference to the accompanying drawings. FIG. 1A is a side cross-sectional view illustrating a state in which a seamless can is supported by an example of a can support member of the disclosure, and FIG. 1B is a perspective view of the example of the can support member.

A seamless can 1 applied to the can support member of the disclosure schematically includes a bottom portion 2 and a barrel portion 3, and the bottom portion 2 is formed with an annular ground contact portion 4, a dome portion 6 recessed upward in a can axial direction from the ground contact portion 4 via an inner wall 5, and a tapered chime portion 7 that is continuous from the ground contact portion 4 to a lower end of the barrel portion 3 and has an outer diameter increasing upward in the can axial direction.

A can support member 10 includes a drive shaft 12 installed in a base portion 11 and movable in the can axial direction, and a can support portion 13 installed at a tip of the drive shaft 12. The can support portion 13 includes a holding portion 14 having a flat surface portion 14a in a horizontal direction with respect to the can axial direction, which contacts the ground contact portion 4 of the can bottom portion, and an annular sidewall 15 extending in the axial direction so as to surround an outer peripheral edge of the holding portion 14. As is apparent from FIG. 1A, the annular sidewall 15 has a shape in which an inner surface 15a thereof substantially matches the chime portion 7 of the can bottom portion, and the inner surface 15a surrounds the chime portion 7 from outside the can, so that the entire chime portion 7 is supported and the can body 1 is restricted from moving horizontally with respect to the can axial direction.

In addition, as is clear from FIG. 1B, the annular sidewall 15 has slits 16, 16 formed at three locations and extending in the can axial direction from an upper end to a lower end of the annular sidewall 15, and a stripper wheel is provided with strippers described below that do not interfere with the slits 16, so that the can body can be easily installed on and separated from the can support member 10 according to vertical movement of the can support member 10.

FIGS. 2A, 2B, 2C, and 2D are diagrams for illustrating an operation of the can support member of the disclosure in necking processing.

FIG. 2A is a diagram illustrating a state in which the can body 1 is supplied from a conveying star wheel (not illustrated) and placed on the can support member 10. In this state, strippers 20 are inserted into the slits 16 of the annular sidewall 15, an upper end of the annular sidewall 15 and upper end surfaces of the stripper 20 are flush with each other, or the upper end surfaces of the stripper 20 are located at positions above the upper end of the annular sidewall 15, and the ground contact portion 4 of the can bottom portion is supported by the upper end surfaces of the strippers.

Next, when the can support member 10 is moved upward in the axial direction and thus the upper end surfaces of the strippers 20 that do not follow the rising of the can support member 10 reach the same position as the flat surface portion 14a of the can support member 10, the ground contact portion 4 of the can bottom portion contacts the flat surface portion 14a of the holding portion 14, and the chime portion 7 also contacts the inner surface 15a of the annular sidewall 15. In this state, when the can support member 10 is further moved upward in the axial direction, an upper opening of the can body 1 is inserted into a necking tool 30 and subjected to necking processing, as illustrated in FIG. 2B. In this state, the ground contact portion 4 of the can body is supported in the axial direction by the flat surface portion 14a of the holding portion 14, and the chime portion 7 is supported by the inner surface 15a of the annular sidewall 15. Therefore, stress that causes deformation of the chime portion 7 is not generated. Further, since the can body is supported at the can bottom in the axial direction and the horizontal direction, the can body is not displaced in the horizontal direction during the necking processing, and the necking processing is reliably performed.

FIG. 2C is a diagram illustrating a state in which the necking processing is completed, the can support member 10 is moved downward in the axial direction, and the can body is removed from the necking tool 30. In this state, the can bottom portion is supported by the can support member 10 at the ground contact portion 4 and the chime portion 7.

Next, as illustrated in FIG. 2D, when the can support member 10 is moved downward in the axial direction and thus the upper end surfaces of the strippers 20 reach the same positions as the upper end of the annular sidewall 15 of the can support member 10, the ground contact portion 4 of the can bottom is supported by the upper end surfaces of the strippers 20. Thereby, the can body 1 can be discharged from the can support member 10, and can be easily supplied to the next necking processing by the conveying star wheel (not illustrated).

Method for Manufacturing Seamless Can

A method for manufacturing a seamless can of the disclosure is a method for manufacturing a seamless can including at least a can body molding step and a necking step, in which in the necking step, necking processing is performed in a state where the ground contact portion and the chime portion of the can bottom portion are supported and fixed from outside the can by using the can support member described above.

That is, as described above, in the necking step, by supporting the can body by the can support member of the disclosure, not only the ground contact portion of the can bottom portion but also the chime portion is supported by the surface matching the shape of the chime portion, and therefore, even if a load is applied in the axial direction of the can body, the deformation of the chime portion can be effectively prevented. In addition, since the can body is supported in the axial direction and the horizontal direction from outside the can, the necking processing can be performed in a state where the can body is firmly supported and fixed without being displaced, and therefore, the necking processing can be efficiently and reliably performed.

In addition, as described above, the annular sidewall is formed with a plurality of slits, and the stripper wheel is provided with the strippers that do not interfere with the slits, thereby facilitating the supply of a can from the conveying star wheel to the can support member, the placing of a can on the can support member and the pushing of a can into the necking tool, the removal of a can from the can support member, and the supply of a can to the conveying star wheel.

Further, in addition to the can molding step and the necking step, the manufacturing method of the disclosure may include, as necessary, steps known in the method of the related art for manufacturing a seamless can, such as a trimming step, a washing step, a printing step, and a flanging step. Although not limited thereto, it is preferable that the respective steps are performed in the order of the can molding step, the trimming step, the washing step, the printing step, the necking step, and the flanging step.

Additionally, in the manufacturing method of the disclosure, it is particularly preferable to provide a bottom reforming step before the necking step. That is, in the bottom reforming step, in order to enhance the pressure resistance strength particularly in the can bottom portion of the thin-walled can body, a pressing body is inserted into the can body, and the bottom portion of the can body is pressed by the pressing body and a molding die installed on the outer surface side of the can body, thereby curving an inner peripheral wall inward in a can radial direction to form an annular curved end portion having a ground contact portion. However, the chime portion is also formed as a gently concave curved surface together with the curved end portion, and has a shape that is likely to be deformed during molding. Therefore, when the can body is supported using the can support member of the disclosure, the deformation of the chime can be effectively suppressed during the necking processing, even if the chime portion has such a shape, because the annular sidewall having the inner surface matching the shape of the chime portion is provided.

In the method for manufacturing a seamless can of the disclosure, techniques known in the method of the related art for manufacturing a seamless can may be adopted, except that the necking processing is performed using the can support member described above in the necking step.

For example, as the can body molding step, a method known in the related art, such as drawing, drawing and deep drawing, drawing and ironing, drawing, bending and stretching, and ironing, can be employed.

In addition, the shape of the seamless can is not limited to the seamless can having a shape illustrated in FIGS. 1A and 1B as long as a shape of the bottom portion is the shape described above, and various shapes of the seamless can, such as a so-called bottle can in which a neck portion is greatly reduced in diameter and a screw portion is provided, can be manufactured.

Furthermore, as the metal plate constituting the seamless can, all metal plates used in the related art for the seamless can, such as a surface-treated steel plate and an aluminum alloy plate, can be used, but the aluminum alloy plate that is likely to be deformed due to thinning is particularly preferable. These metal plates may be resin-coated metal plates coated with a thermoplastic resin such as polyester resin. When such a resin-coated metal plate is used, an outer surface coating process and an inner surface coating process can be omitted.

Apparatus for Manufacturing Seamless Can

According to the disclosure, there is provided an apparatus for manufacturing a seamless can, the apparatus including at least a can body molding means, a necking means, and a conveying means for connecting the can body molding means and the necking means, in which the necking means includes a can support member capable of supporting and fixing a can bottom of a can body conveyed from the conveying means, and the can support member is a can support member capable of supporting and fixing a ground contact portion and a chime portion of a can bottom portion from outside the can.

FIG. 3 is a diagram for illustrating an example of a necking means in an apparatus for manufacturing a seamless can of the disclosure, showing one station for the necking processing performed in multiple stages, and for convenience of explanation, showing a state where the can body is not present and the drive shaft is moved to the necking tool side (a position when the can body is subjected to the necking processing). In addition, in the specific examples illustrated in FIGS. 1A, 1B, 2A, 2B, 2C, and 2D, the can support member is arranged with the vertical direction in the drawings as the can axial direction, but as illustrated in FIG. 3, the can support member may be installed in an apparatus in which the can axial direction is the horizontal direction. Additionally, of course, the can support member can be appropriately changed depending on the arrangement of each means in the manufacturing apparatus, the conveying method, and the like.

In an example of the necking means illustrated in FIG. 3, a necking tool, generally indicated by 30, a star wheel 40 having a plurality of pockets 41 formed therein for holding can body barrel portions, three can support members 10, and a stripper wheel 50 for arranging strippers 20 are provided.

As illustrated in FIGS. 1A and 1B, the can support member 10 includes the drive shaft 12 movable in the can axial direction, and the can support portion 13 provided at the tip of the drive shaft 12, and supports the ground contact portion of the can bottom by the flat surface portion 14a of the holding portion 14 of the can support portion 13, and the chime portion by the inner surface 15a of the annular sidewall 15. However, the structure of the can support member 10 is not limited thereto, and the can support portion 13 and the flat surface portion 14a may be formed as one component, and may also be formed as one component integrated with the drive shaft 12. In addition, the stripper wheel 50 is formed with a hole 51 for arranging the can support member 10 to be movable in the can axial direction, and the strippers 20 are installed on a peripheral edge of the hole 51. Note that, although the stripper 20 is detachably installed on the stripper wheel 50 in FIG. 3, the stripper 20 may be integrally formed with the hole 51.

As illustrated in FIGS. 2A, the strippers 20 are formed at positions corresponding to the slits 16 formed in the annular sidewall 15 of the can support member 10 in the can axial direction, and are formed so as not to interfere with the slits 16 when the can support member 10 is moved in the can axial direction. That is, when the can support member 10 is moved upward in FIG. 2B, and thus the strippers 20 are moved relatively below the flat surface portion 14a, the can body 1 is supported by the can support member 10 and the ground contact portion is supported by the flat surface portion 14a of the can support portion 13. In this state, the upper opening of the can body 1 is pushed into the necking tool 30 by the can support member 10 and subjected to necking processing. After the necking processing is completed, when the can support member 10 is moved downward in FIG. 2C, and thus the strippers 20 are moved into the slits 16, the can body 1 is supported by the upper end surfaces of the strippers 20, becomes separable from the can support member 10, is transferred to the conveying star wheel (not illustrated) in a state of being supported by the star wheel 40, and is supplied to the next necking means.

In the apparatus for manufacturing a seamless can of the disclosure, the respective means known in the apparatus of the related art for manufacturing a seamless can, such as a trimming means, a washing means, a printing means, a necking means, and a flanging means, may be adopted as necessary, except that the necking means includes the can support member of the disclosure described above.

In the apparatus for manufacturing a seamless can of the disclosure, it is preferable that the respective means are arranged in the order of the can body molding means, the trimming means, the washing means, the printing means, the bottom remolding means, the necking means, and the flanging means, and the conveying means is provided between the respective means, although the disclosure is not limited thereto.

While preferred embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure. The scope of the disclosure, therefore, is to be determined solely by the following claims.