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EP-4741078-A1 - CAN SUPPORT MEMBER, AND SEAMLESS CAN MANUFACTURING METHOD AND MANUFACTURING DEVICE

EP4741078A1EP 4741078 A1EP4741078 A1EP 4741078A1EP-4741078-A1

Abstract

There is provided a can support member for supporting and fixing a can body in a can manufacturing process. The can body is a seamless can including 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. Thus, the can support member can support and fix the can body without causing deformation of the chime portion.

Inventors

  • YUGE, HIDEKI
  • MIYAMOTO, TAKESHI

Assignees

  • Toyo Seikan Co., Ltd.

Dates

Publication Date
20260513
Application Date
20240607

Claims (7)

  1. A can support member for supporting and fixing a can body in a can manufacturing process, wherein the can body is a seamless can comprising a barrel portion and a bottom portion, the bottom portion has a bottom shape comprising 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.
  2. The can support member according to claim 1, comprising: a can support portion comprising 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.
  3. The can support member according to claim 2, wherein 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.
  4. The can support member according to claim 1 or 2, wherein the can body comprises 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.
  5. A method for manufacturing a seamless can, the method comprising at least: can body molding; 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.
  6. The method for manufacturing a seamless can according to claim 5, the method further comprising bottom reforming before the necking, wherein 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 comprising a ground contact portion.
  7. An apparatus for manufacturing a seamless can, the apparatus comprising at least: a can body molding means; a necking means; and a conveying means connecting the can body molding means and the necking means, wherein the necking means comprises 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.

Description

Technical Field The present invention 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 Art 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, Patent Document 1 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, Patent Document 2 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 Patent Document 3 below. Citation List Patent Literature Patent Document 1: JP 2018-177289 APatent Document 2: JP 2016-043991 APatent Document 3: JP 2000-503260 T Summary of Invention Technical Problem 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 Patent Document 1, 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 Patent Document 2, 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 present invention 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 present invention is to provide a method and an apparatus for manufacturing a thin-walled seamless can without causing a molding defect. Solution to Problem According to the present invention, 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 chim