Tank support member, method and apparatus for manufacturing seamless tank

Abstract

The present invention is a can support member for supporting and fixing a can body, which is a seamless can having a main body part and a bottom part having a bottom part shape provided with at least a ground part and a tapered flange part connected from the ground part to the lower end of the main body part. The outer diameter of the tank support member increases upward in the axial direction of the tank, and the tank support member can support and fix the tank body without deformation of the flange portion by supporting the ground portion and the flange portion from the outside of the tank.

Description

Technical Field

[0001] This invention relates to a support component for a can body used in a can manufacturing process, and more specifically, to a can support component that can be supported and fixed without causing deformation of the can body during the necking process in the manufacturing of seamless cans, a manufacturing method using the can support component, and a manufacturing apparatus. Background Technology

[0002] As containers for storing beverages, food, etc., seamless cans (Drawn and Ironed Cans, DI cans) formed through deep drawing and thinning processes are widely used. For these seamless cans, in order to save resources and reduce weight, the wall thickness of the can body is required to be thin. In the case of a typical 350ml seamless can for carbonated beverages, the thickness of the aluminum alloy sheet used as the material is generally less than 0.26mm. Seamless cans made by deep drawing and thinning such thin-walled metal sheets, especially at the bottom, tend to have reduced pressure resistance. Therefore, in order to achieve higher pressure resistance, various solutions have been proposed for the shape of the can bottom.

[0003] For example, Patent Document 1 describes a seamless can, which is an aluminum seamless can having a bottom and a thin-walled main body. The bottom is composed of a rounded top located in the center and protruding upward, a grounding portion descending from the periphery of the rounded top, and a protruding edge extending outward and upward from the grounding portion and connected to the lower end of the main body.

[0004] Furthermore, Patent Document 2 describes a seamless can in order to improve the pressure resistance of the thin-walled bottom. A first concave curved surface is formed on the inner peripheral wall connected to the dome, which is concave in a radial direction perpendicular to the can axis. The dome has: a dome top located on the can axis; a second concave curved surface connected to the radial direction of the dome top, having a concave curve with a radius of curvature smaller than that of the dome top; and a tapered portion disposed on the outer peripheral edge of the dome top, connecting the first and second concave curved surfaces, and forming a straight line connecting to both the first and second concave curved surfaces.

[0005] On the other hand, in the seamless can formed by deep drawing and thinning of thin-walled metal sheet as described above, the following operation is also performed: the neck of the can body after deep drawing and thinning is reduced in diameter by necking. In this case, a solution as shown in Patent Document 3 is proposed, that is, a container support that can move relative to the die used to form the neck in the can axis direction is used, and the processing is performed by moving it.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2018-177289

[0009] Patent Document 2: Japanese Patent Application Publication No. 2016-043991

[0010] Patent Document 3: Japanese Patent Publication No. 2000-503260 Summary of the Invention

[0011] The problem the invention aims to solve

[0012] However, in industrial can manufacturing processes, especially in necking, the can body is subjected to a large compressive load in the axial direction because the upper part of the can is pressed into the necking tool for processing. Therefore, in thin-walled cans with convex edges as described in Patent Document 1, the convex edges that are not supported by support members may be deformed by the axial load applied to the ground. In particular, in seamless cans formed by adjusting the shape of the inner peripheral wall of the annular convex part through bottom modification processing as described in Patent Document 2 above, the outer peripheral wall (convex edge) is also formed as a gently concave surface, making it more prone to deformation caused by necking.

[0013] Therefore, the object of the present invention is to provide a support member that can support and fix the can body without deforming the protruding edge during the molding of a seamless can with a protruding edge.

[0014] Another object of the present invention is to provide a manufacturing method and apparatus for manufacturing thin-walled seamless cans without producing molding defects.

[0015] Solution for solving the problem

[0016] According to the present invention, a can support member is provided for supporting and fixing a can body during a can manufacturing process. The can support member is characterized in that the can body is a seamless can having a main body and a bottom, the bottom having a bottom shape having at least a grounding portion and a tapered convex edge, the tapered convex edge being connected from the grounding portion to the lower end of the main body, the outer diameter of which increases towards the can axis, and the can support member supporting the grounding portion and the convex edge from the outside of the can.

[0017] In the tank support component of the present invention, the preferred embodiment is:

[0018] (1) The can support has a can support and a movable shaft. The can support includes: a holding portion that abuts against the grounding portion to support the bottom; and an annular sidewall that extends from the periphery of the holding portion and has an inner surface that abuts against the protruding edge; the movable shaft moves the can support in the can shaft direction.

[0019] (2) A plurality of slits are formed on the annular sidewall, the plurality of slits extend along the tank axis and from the upper end to the lower end of the annular sidewall, and a demolding device is provided on the demolding wheel so as to detach the tank body from the tank support without interfering with the slits;

[0020] (3) The tank body has: a round top that protrudes into the tank from the center of the bottom; and an inner peripheral wall that extends downward from the outer periphery of the round top in the direction of the tank axis and bends inward in the direction of the tank diameter; the grounding part is located at the lower end of the inner peripheral wall and the lower end of the protruding edge.

[0021] According to the present invention, a method for manufacturing a seamless can is also provided. The method includes at least a can body forming process and a necking process. The method is characterized in that, in the necking process, the necking process is performed while the grounding portion and the protruding edge of the bottom of the can are supported and fixed from the outside of the can using a can support member.

[0022] In the seamless can manufacturing method of the present invention, it is preferable to have a bottom shaping process before the necking process, in which a pressing body is inserted into the interior of the can body and the bottom of the can body is pressed by the pressing body and a forming mold provided on the outer surface side of the can body, thereby bending the inner peripheral wall inward in the can diameter direction to form an annular curved end with a grounding portion.

[0023] According to the present invention, a manufacturing apparatus for a seamless can is also provided. The apparatus includes at least a can forming unit, a necking unit, and a conveying unit connecting the units. The apparatus is characterized in that the necking unit has a can support member capable of supporting and fixing the bottom of the can body conveyed from the conveying unit. The can support member can support and fix the grounding portion and the protruding edge of the bottom of the can from the outside of the can.

[0024] The effects of the invention

[0025] In the can support member of the present invention, a retaining portion and an annular sidewall that match the shape of the bottom of the can are provided. Therefore, the bottom of the can can be supported not only axially from the outside but also horizontally, thereby enabling reliable necking processing. In addition, the inner surface of the annular sidewall that abuts against the convex edge of the bottom of the can has a shape that matches the convex edge. Therefore, even when pressing the bottom of the can along the can axis to press the can into the necking tool during necking processing, the pressing is performed while the convex edge, which is prone to deformation due to its thin wall, is supported by the inner surface of the annular sidewall, thus effectively preventing deformation.

[0026] Furthermore, multiple slits are formed on the annular sidewall of the tank support component, and a demolding device that does not interfere with the slits is provided on the demolding wheel. Thus, by moving the demolding device relative to the slit, with the upper end of the demolding device located at the same position as or above the upper end of the annular sidewall, the tank can be easily separated from the tank support component.

[0027] Furthermore, in the manufacturing method and apparatus for a seamless can using the can support member of the present invention, necking can be performed while the can body is supported and fixed by the can support member without the bottom contact portion and protruding edge of the can swaying from the outside of the can in the axial and horizontal directions. Therefore, necking can be performed efficiently and reliably. In addition, by moving relative to the demolding device within the slit, with the upper end of the demolding device located at the same position as or above the upper end of the annular sidewall, there is no longer any interference from the annular sidewall portion in the direction of travel of the can body after it is separated from the can support member. Therefore, the can body can be smoothly transferred to the next process.

[0028] Furthermore, in seamless cans that have undergone bottom modification, deformation of the convex edge can also be effectively prevented by using the can support component of the present invention. Attached Figure Description

[0029] Figure 1 The figures are for illustrating an example of the can support member of the present invention. (A) is a side sectional view showing the state of supporting the bottom of the can, and (B) is a perspective view.

[0030] Figure 2 This is a diagram illustrating the operation of the tank support component of the present invention.

[0031] Figure 3 This is a partial perspective view illustrating an example of the necking process in a manufacturing apparatus for a seamless can of the present invention. Detailed Implementation

[0032] (Tank support components)

[0033] The tank support component of the present invention will be described with reference to the accompanying drawings. Figure 1 (A) is a side sectional view showing a seamless can in a supported state in an example of the can support member of the present invention. Figure 1 (B) is a perspective view of an example of a tank support component.

[0034] In short, the seamless can 1 of the can support component applicable to the present invention is composed of a bottom 2 and a main body 3. The bottom 2 is formed with: an annular grounding portion 4; a rounded top 6, which is recessed from the grounding portion 4 via the inner sidewall 5 toward the can axis; and a tapered convex edge 7, which is connected from the grounding portion 4 to the lower end of the main body 3, and whose outer diameter increases toward the can axis.

[0035] The can support member 10 consists of a drive shaft 12 disposed at a base 11 and movable in the can axial direction, and a can support portion 13 disposed at the front end of the drive shaft 12. The can support portion 13 consists of a retaining portion 14 and an annular sidewall 15. The retaining portion 14 has a planar portion 14a that abuts against the grounding portion 4 at the bottom of the can and is horizontal in the can axial direction. The annular sidewall 15 extends axially to surround the outer periphery of the retaining portion 14. Figure 1 As can be seen from (A), the inner surface 15a of the annular sidewall 15 has a shape that roughly matches the shape of the protruding edge 7 at the bottom of the can, and the inner surface 15a surrounds the protruding edge 7 from the outside of the can, thus supporting the entire protruding edge 7 and restricting the movement of the can body 1 in the horizontal direction relative to the can axis.

[0036] In addition, from Figure 1 As can be seen from (B), three slits 16, 16... are formed on the annular sidewall 15. These slits 16 extend along the can axis and from the upper end to the lower end of the annular sidewall 15. The demolding wheel is equipped with a demolding device described below. The demolding device does not interfere with the slits 16. Thus, the can body can be easily placed on the can support member 10 and separated from the can support member 10 as the can support member 10 moves up and down.

[0037] Figure 2 This is a diagram illustrating the necking process of the can support component of the present invention.

[0038] Figure 2 Figure (A) shows the state in which the tank 1 is supplied from the transfer star wheel (not shown) and placed on the tank support member 10. In this state, the demolding device 20 is inserted into the slit 16 of the annular sidewall 15, the upper end of the annular sidewall 15 is at the same position as the upper end face of the demolding device 20, or the upper end face of the demolding device 20 is located above the upper end of the annular sidewall 15, and the grounding part 4 at the bottom of the tank is supported by the upper end face of the demolding device.

[0039] Next, the can support member 10 moves axially upward. When the upper end face of the demolding device 20, which does not follow the rise of the can support member 10, reaches the same position as the flat portion 14a of the can support member 10, the grounding portion 4 of the can bottom abuts against the flat portion 14a of the holding portion 14, and simultaneously the protruding edge 7 abuts against the inner surface 15a of the annular sidewall 15. In this state, the can support member 10 moves further axially upward, as... Figure 2As shown in (B), a necking tool 30 is inserted into the upper opening of the tank body 1 to perform necking. In this state, the grounding portion 4 of the tank body is axially supported by the flat portion 14a of the holding portion 14, while the protruding edge 7 is supported by the inner surface 15a of the annular sidewall 15, thus preventing stress that could deform the protruding edge 7. Furthermore, since the tank body is supported axially and horizontally at the bottom, it does not wobble horizontally during necking, enabling reliable necking.

[0040] Figure 2 (C) is a diagram showing the state after the necking process is completed, with the can support member 10 moving axially downwards and the can body disengaging from the necking tool 30. In this state, the grounding portion 4 and the protruding edge 7 at the bottom of the can are supported by the can support member 10.

[0041] Next, as Figure 2 As shown in (D), the can support member 10 moves axially downwards, and when the upper end face of the demolding device 20 reaches the same position as the upper end of the annular sidewall 15 of the can support member 10, the grounding portion 4 of the can bottom is supported by the upper end face of the demolding device 20. Thus, the can body 1 can be discharged from the can support member 10 and can be easily supplied to the next stage of necking processing via a transfer star wheel (not shown).

[0042] (Manufacturing method of seamless tank)

[0043] The seamless can manufacturing method of the present invention includes at least a can body forming process and a necking process. An important feature of the method is that, in the necking process, the can support member is used to perform the necking process while the grounding part and the protruding edge of the bottom of the can are supported and fixed from the outside of the can.

[0044] That is, as described above, in the necking process, by using the can support member of the present invention to support the can body, not only the grounding part at the bottom of the can, but also the convex edge is supported by a surface that matches the shape of the convex edge. Therefore, even if a load is applied in the axial direction of the can body, deformation of the convex edge can be effectively prevented. In addition, since the can is supported from the outside in both the axial and horizontal directions, the necking process can be performed while the can body is firmly supported and fixed without shaking, thus enabling efficient and reliable necking.

[0045] In addition, as described above, multiple slits are formed on the annular sidewall, and a demolding device that does not interfere with the slits is provided on the demolding wheel, thereby enabling easy supply of the can from the transfer star wheel to the can support member, placement of the can on the can support member and pressing into the necking tool, removal of the can from the can support member, and supply to the transfer star wheel.

[0046] Furthermore, in the manufacturing method of the present invention, in addition to the can forming process and the necking process, processes conventionally known in the manufacturing method of seamless cans may be included as needed, such as the edge trimming process, the cleaning process, the printing process, and the flange processing process. Although not limited thereto, it is preferable to perform each process in the order of can forming process, edge trimming process, cleaning process, printing process, necking process, and flange processing process.

[0047] Furthermore, in the manufacturing method of the present invention, it is particularly preferable to include a bottom shaping process before the necking process. That is, regarding the bottom shaping process, in order to improve the pressure resistance of the bottom of the can, especially thin-walled cans, a pressing body is inserted into the can body, and the bottom of the can body is pressed by the pressing body and a molding die provided on the outer surface of the can body. This causes the inner peripheral wall to bend inward in the can diameter direction, forming an annular curved end with a ground contact portion. However, outside the curved end, the convex edge is also formed as a gently sloping concave surface, resulting in a shape that is prone to deformation during molding. Therefore, when using the can support member of the present invention to support the can body, even with this type of convex edge, since it has an annular sidewall with an inner surface matching the shape of the convex edge, deformation of the convex edge can be effectively suppressed after the necking process.

[0048] In the seamless can manufacturing method of the present invention, in the necking process, in addition to using the above-mentioned can support member for necking processing, the methods in conventional seamless can manufacturing methods can be used.

[0049] For example, as a can forming process, conventionally known methods such as deep drawing, deep drawing / deep drawing, deep drawing / thinning, deep drawing / bending and stretching / thinning can be used.

[0050] Furthermore, regarding the shape of the seamless can, it is not limited to any shape other than the shape described above. Figure 1 Seamless cans of the shape shown can be manufactured in various shapes, such as bottles or jars, with a large neck diameter reduction and threaded sections.

[0051] Furthermore, the metal sheet constituting the seamless can can be any metal sheet conventionally used for seamless cans, such as surface-treated steel sheets, aluminum alloy sheets, etc., but aluminum alloy sheets, which are easily deformed by thinning, are particularly preferred. These metal sheets can also be resin-coated metal sheets that have undergone resin coating using thermoplastic resins such as polyester resin. When using such resin-coated metal sheets, the outer surface coating process and the inner surface coating process can be omitted.

[0052] (Apparatus for manufacturing seamless tanks)

[0053] According to the present invention, in a seamless can manufacturing apparatus having at least a can forming unit, a necking unit, and a conveying unit connecting the units, an important feature is that the necking unit is provided with a can support member capable of supporting and fixing the bottom of the can body conveyed from the conveying unit, the can support member capable of supporting and fixing the grounding portion and the protruding edge of the bottom of the can from the outside of the can.

[0054] Figure 3 This diagram illustrates an example of a necking unit in the manufacturing apparatus of the present invention, showing a station where a multi-stage necking process is performed. For ease of explanation, it is presented with the drive shaft moved to the necking tool side (the position when the tank is receiving the necking process) without the tank. Furthermore, in the... Figure 1 and Figure 2 In the specific example shown, the tank support components are arranged with the vertical direction of the attached drawing as the tank axis direction, but as... Figure 3 As shown, the tank support component can also be set on a device with the tank axis in a horizontal direction, and can be appropriately changed according to the arrangement of each unit in the manufacturing device or the conveying method.

[0055] exist Figure 3 In one example of the necking unit shown, the following are provided: a necking tool, generally indicated by 30; a star-shaped wheel 40, which has multiple grooves 41 for holding the main body of the can; three can support members 10; and a demolding wheel 50 for configuring the demolding device 20.

[0056] like Figure 1 As shown, the can support member 10 consists of a drive shaft 12 movable in the can axial direction and a can support portion 13 located at the front end of the drive shaft 12. The can support portion of the bottom of the can is supported by the flat portion 14a of the holding portion 14 of the can support portion 13, and the protruding edge is supported by the inner surface 15a of the annular sidewall 15. However, the structure of the can support member 10 is not limited to this; the can support portion 13 and the flat portion 14a can be formed from a single part, or even from a single part integrated with the drive shaft 12. Furthermore, a hole 51 is formed in the demolding wheel 50 for movably arranging the can support member 10 in the can axial direction, and a demolding device 20 is provided around the periphery of this hole 51. Additionally, in Figure 3 In this case, the demolding device 20 is detachably mounted on the demolding wheel 50, but it can also be integrally formed with the hole 51.

[0057] like Figure 2 As shown, the demolding device 20 is formed at a position consistent with the slit 16 formed on the annular sidewall 15 of the can support member 10 in the can axial direction, and is configured such that it does not interfere with the slit 16 when the can support member 10 moves along the can axial direction. That is, when the can support member 10 moves towards the can axial direction, the demolding device 20 can move towards the can support member 10. Figure 2When the demolding device 20 moves upward and is positioned relatively lower than the flat portion 14a, the tank body 1 is supported by the tank support member 10, and the grounding portion is supported by the flat portion 14a of the tank support member 13. In this state, the upper part of the opening of the tank body 1 is pressed into the necking tool 30 by the tank support member 10, thereby performing necking processing. After the necking processing is completed, when the can support member 10 moves upward... Figure 2 When the demolding device 20 moves into the slit 16 by moving downwards, the tank 1 is supported by the upper end face of the demolding device 20 and is in a state that can be separated from the tank support member 10. It is then transferred to the transfer star wheel (not shown) while supported by the star wheel 40 and supplied to the next necking unit.

[0058] In the seamless can manufacturing apparatus of the present invention, in addition to the necking unit having the can support member of the present invention, various units in conventionally known seamless can manufacturing apparatuses, such as edge trimming unit, cleaning unit, printing unit, necking unit, flange processing unit, etc., can be used as needed.

[0059] In the seamless can manufacturing apparatus of the present invention, although not limited thereto, it is preferable to arrange the can body forming unit, the edge trimming unit, the cleaning unit, the printing unit, the bottom shaping unit, the necking unit, and the flange processing unit in sequence, and to provide a conveying unit between each unit.

[0060] Explanation of reference numerals in the attached figures

[0061] 1: Seamless tank; 2: Bottom; 3: Main body; 4: Grounding part; 5: Inner sidewall; 6: Round top; 7: Raised edge; 10: Tank support component; 11: Base; 12: Drive shaft; 13: Tank support; 14: Holding part; 15: Annular sidewall; 16: Slit; 20: Demolding device; 30: Necking tool; 40: Star wheel; 50: Demolding wheel.

Claims

1. A can body supporting member for supporting a can body fixed in a can body manufacturing process, the can body supporting member characterized by, the can body being a seamless can body having a main body portion and a bottom portion, the bottom portion having a bottom portion shape at least having a land portion and a tapered flange portion connected to a lower end of the main body portion from the land portion, an outer diameter of the tapered flange portion increasing as it goes upward in a can axis direction; the can body supporting member supporting the land portion and the flange portion from an outer side of the can body.

2. The can body supporting member according to claim 1, wherein, the can body supporting member has a can body supporting portion and a movable shaft, the can body supporting portion having a holding portion abutting against the land portion to support the bottom portion and a ring-shaped side wall extending from a peripheral portion of the holding portion and having an inner side surface abutting against the flange portion, and the movable shaft moving the can body supporting portion in the can axis direction.

3. The can body supporting member according to claim 2, wherein, a plurality of slits are formed in the ring-shaped side wall, the plurality of slits extending in the can axis direction and from an upper end to a lower end of the ring-shaped side wall, and a stripper is provided on a stripper wheel, the stripper separating the can body from the can body supporting portion without interfering with the slits.

4. The can body supporting member according to claim 1 or 2, wherein, the can body has a dome portion protruding toward an inner side of the can body in a center of the bottom portion and an inner peripheral wall extending downward in the can axis direction from an outer periphery of the dome portion and bending toward an inner side in a can diameter direction, and the land portion is located at a lower end of the inner peripheral wall and a lower end of the flange portion.

5. A method of manufacturing a seamless can body, the method having at least a can body forming process and a necking process, the method characterized by, in the necking process, necking is performed while the land portion and the flange portion of the bottom portion of the can body are supported and fixed from an outer side of the can body by a can body supporting member.

6. The method of manufacturing a seamless can body according to claim 5, wherein, the method has a bottom portion reforming process before the necking process, in the bottom portion reforming process, an inner peripheral wall is bent toward an inner side in a can diameter direction by inserting a pressing body into an inside of the can body and pressing the bottom portion of the can body with the pressing body and a forming mold provided on an outer surface side of the can body, and a ring-shaped bent end portion having the land portion is formed.

7. An apparatus for manufacturing a seamless can body, the apparatus having at least a can body forming unit, a necking unit, and a conveying unit connecting between the units, the apparatus characterized by, the necking unit has a can body supporting member capable of supporting and fixing a bottom portion of a can body conveyed from the conveying unit, and the can body supporting member is capable of supporting and fixing a land portion and a flange portion of the bottom portion of the can body from an outer side of the can body.

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