Can support member, and manufacturing method and manufacturing apparatus of seamless can

Abstract

To provide a support member which can support and fix a can body without causing deformation of a chime part, in molding a seamless can of a bottom shape having a chime part.SOLUTION: Provided is a can support member for supporting and fixing a can body in a can manufacturing process. The can body is a seamless can having a body part and a bottom part. The bottom part has a bottom shape comprising at least a grounding part, and a tapered chime part which is continuous from the grounding part to a body part lower end and whose outer diameter increases upward in a can axis direction. The can support member supports the grounding part and the chime part from outside of the can.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a support member for a can body used in a can-making process, and more specifically, to a can support member that can support and fix a can body without causing deformation during the necking process in the manufacture of seamless cans, and a manufacturing method and manufacturing apparatus using this can support member. [Background technology]

[0002] Seamless cans (DI cans) formed by drawing and ironing or the like are widely used as can bodies for storing beverages, foods, etc., and there is a demand for thin-walled can bodies for such seamless cans in order to conserve resources and reduce weight. In the case of typical seamless cans for 350 ml carbonated beverages, the thickness of the aluminum alloy plate material is almost always 0.26 mm or less, and seamless cans made by drawing and ironing such thin metal plates are prone to a decrease in pressure resistance, particularly at the bottom, so various proposals have been made for the shape of the can bottom to provide higher pressure resistance.

[0003] For example, Patent Document 1 listed below describes an aluminum seamless can having a bottom and a thin-walled body, the bottom of which is composed of a dome portion located in the center and bulging upward, a ground portion that descends from the periphery of the dome portion, and a chime portion that extends at an angle outward and upward from the ground portion and is connected to the lower end of the body portion. Furthermore, Patent Document 2 listed below describes a seamless can in which, in order to improve the pressure resistance of the thinned bottom, an inner wall connected to the dome portion is formed with a first concave curved surface portion that is curved in a radially outward direction perpendicular to the can axis, and the dome portion is formed with a dome top located on the can axis, a second concave curved surface portion that is connected to the radially outward side of the dome top and has a concave curved shape with a smaller radius of curvature than the dome top, and a tapered portion that is located on the outer periphery of the dome portion, connects the first concave curved surface portion and the second concave curved surface portion, and is linearly tangent to the first concave curved surface portion and the second concave curved surface portion.

[0004] On the other hand, even in the case of seamless cans formed by drawing and ironing thin metal sheets as described above, the can body after drawing and ironing is subjected to a necking process to reduce the diameter of the neck portion. In this case, it has been proposed to carry out the processing by using a container support that can be moved in the axial direction of the can relative to a die for forming the neck, as shown in Patent Document 3 below. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-177289 A [Patent Document 2] JP 2016-043991 A [Patent Document 3] Special Publication No. 2000-503260 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in industrial can-making processes, particularly in necking, the upper part of the can body is forced into a necking tool, which places a large compressive load on the can body in the axial direction. Therefore, in a thin-walled can body having a chime part as described in Patent Document 1, the chime part that is not supported by a support member may buckle due to the axial load applied to the contact part. In particular, in a seamless can formed by adjusting the shape of the inner peripheral wall of the annular protrusion by bottom reforming as described in Patent Document 2, the outer peripheral wall (chime part) is also formed as a gently concave curved surface, which makes it even more susceptible to deformation due to necking.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a support member capable of supporting and fixing a can body without causing deformation of the chime portion during molding of a seamless can having a chime portion. Another object of the present invention is to provide a method and an apparatus for producing thin-walled seamless cans without causing molding defects. [Means for solving the problem]

[0008] According to the present invention, there is provided a can support member for supporting and fixing a can body in a can making process, the can body being a seamless can having a body and a bottom, the bottom having a bottom shape including at least a ground portion and a tapered chime portion that is connected from the ground portion to the lower end of the body and has an outer diameter that increases upward in the axial direction of the can, the can support member supporting the ground portion and the chime portion from outside the can.

[0009] In the can support member of the present invention, (1) The can support part includes a holding part that abuts against the grounding part to receive the bottom of the can, and an annular side wall that extends from a peripheral part of the holding part and has an inner surface that abuts against the chime part, and a movable shaft that moves the can support part in the can axial direction. (2) A plurality of slits extending in the axial direction of the can and extending from the upper end to the lower end of the annular side wall are formed in the annular side wall, and a stripper is provided on a stripper wheel to separate the can body from the can support without interfering with the slits. (3) The can body includes a dome portion protruding inwardly from the center of the bottom, and an inner circumferential wall extending downwardly in the can axial direction from the outer circumferential edge of the dome portion and curving inwardly in the can radial direction, and the grounding portion is located at the lower end of the inner circumferential wall and the lower end of the chime portion. is preferred.

[0010] The present invention also provides a method for producing seamless cans which includes at least a can body forming step and a necking step, characterized in that in the necking step, the necking process is carried out in a state in which the ground portion and the chime portion of the can bottom are supported and fixed from the outside of the can by a can support member. In the manufacturing method of a seamless can of the present invention, it is preferable to have a bottom reforming process before the necking process, in which a pressing body is inserted inside the can body and the bottom of the can body is pressed against the pressing body together with a molding die installed on the outer surface side of the can body, thereby curving the inner wall radially inwardly to form an annular curved end portion having a grounding portion.

[0011] The present invention further provides an apparatus for manufacturing seamless cans comprising at least a can body forming means, a necking means, and a conveying means connecting the respective means, wherein the necking means is equipped with a can support member capable of supporting and fixing the bottom of the can body conveyed from the conveying means, and the can support member is capable of supporting and fixing the ground portion and chime portion of the can bottom from the outside of the can. Effect of the Invention

[0012] The can support member of the present invention has a retaining portion and annular side wall that match the shape of the bottom of the can body, so that it can support the bottom of the can body from the outside not only in the axial direction but also in the horizontal direction, and processing in the necking process can be performed reliably. Also, because the inner surface of the annular side wall that abuts against the chime part of the can bottom has a shape that matches the chime part, even when the can bottom is pressed in the axial direction of the can body and the can body is pushed into the necking tool during necking processing, the chime part, which is thin and prone to deformation, is pressed while being supported by the inner surface of the annular side wall, effectively preventing deformation. Furthermore, a plurality of slits are formed in the annular side wall of the can support member, and a stripper wheel is provided with a stripper that does not interfere with the slits. This allows the stripper to move relatively within the slits, and the upper end of the stripper is at the same position as or higher than the upper end of the annular side wall, making it possible to easily separate the can bodies from the can support member.

[0013] In the seamless can manufacturing method and apparatus using the can support member of the present invention, the necking process can be performed efficiently and reliably because the can body can be necked while the can support member supports and fixes the grounding portion and chime portion of the can bottom from the outside of the can without causing deviation in the axial and horizontal directions. Furthermore, the stripper moves relatively within the slit until the upper end of the stripper is at the same position as or higher than the upper end of the annular side wall, so that after the can body is separated from the can support member, there is no interference from the annular side wall in the direction of travel of the can body, and the can body can be smoothly transferred to the next process. Furthermore, by using the can support member of the present invention in seamless cans that have been subjected to bottom reforming processing, deformation of the chime portion can be effectively prevented. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a diagram illustrating an example of a can support member of the present invention, where (A) is a side cross-sectional view showing a state in which the can bottom is supported, and (B) is a perspective view. [Diagram 2] 5A to 5C are diagrams illustrating the operation of the can support member of the present invention. [Diagram 3] FIG. 2 is a partial perspective view for explaining an example of a necking step in the seamless can manufacturing apparatus of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Can support member) The can support member of the present invention will be described with reference to the accompanying drawings, in which Fig. 1(A) is a side cross-sectional view showing an example of the can support member of the present invention supporting a seamless can, and Fig. 1(B) is a perspective view of the example of the can support member. A seamless can 1 used in the can support member of the present invention generally consists of a bottom section 2 and a body section 3. The bottom section 2 is formed with an annular grounding section 4, a dome section 6 that is recessed upward in the axial direction of the can from the grounding section 4 via an inner wall 5, and a tapered chime section 7 that connects from the grounding section 4 to the lower end of the body section 3 and has an outer diameter that increases upward in the axial direction of the can. Can support member 10 is mounted on base 11 and comprises drive shaft 12 movable in the can axial direction, and can support part 13 mounted on the tip of drive shaft 12. Can support part 13 comprises retaining part 14 having flat part 14a horizontal to the can axial direction that abuts against grounding part 4 at the can bottom, and annular side wall 15 extending in the axial direction to surround the outer periphery of retaining part 14. As is clear from Fig. 1(A), annular side wall 15 has an inner surface 15a which has a shape that substantially matches chime part 7 at the can bottom, and this inner surface 15a surrounds chime part 7 from the outside of the can, so that chime part 7 is supported as a whole and movement of can body 1 horizontal to the can axial direction is restricted. As is apparent from FIG. 1(B), the annular side wall 15 has three slits 16, 16..., which extend in the axial direction of the can and reach from the upper end to the lower end of the annular side wall 15. A stripper, which will be described later and does not interfere with the slits 16, is provided on the stripper wheel. This makes it possible to easily install and remove the can body from the can support member 10 in accordance with the up and down movement of the can support member 10.

[0016] FIG. 2 is a diagram for explaining the operation in the necking process of the can support member of the present invention. FIG. 2(A) shows the state in which a can body 1 is supplied from a transfer star wheel (not shown) and placed on the can support member 10. In this state, the stripper 20 is inserted into the slit 16 in the annular side wall 15, and the upper end of the annular side wall 15 and the upper end face of the stripper 20 are either at the same position, or the upper end face of the stripper 20 is located higher than the upper end of the annular side wall 15, and the grounding portion 4 of the can bottom is supported by the upper end face of the stripper. Next, as the can support member 10 moves axially upward, the upper end surface of the stripper 20, which does not follow the upward movement of the can support member 10, reaches the same position as the flat surface 14a of the can support member 10, and the grounding portion 4 of the can bottom abuts against the flat surface 14a of the holding portion 14, and the chime portion 7 also abuts against the inner surface 15a of the annular side wall 15. As the can support member 10 further moves axially upward in this state, the upper opening of the can body 1 is inserted into the necking tool 30 and the necking process is performed, as shown in FIG. 2(B). In this state, the grounding portion 4 of the can body is supported in the axial direction by the flat surface 14a of the holding portion 14, and the chime portion 7 is supported by the inner surface 15a of the annular side wall 15, so that no stress that would cause deformation is generated in the chime portion 7. In addition, since the can body is supported in the axial and horizontal directions by the can bottom, the can body does not wobble horizontally during the necking process, and the necking process is performed reliably.

[0017] 2(C) shows the state after the necking process is completed, the can support member 10 moves axially downward, and the can body is removed from the necking tool 30. In this state, the can bottom is supported by the can support member 10 at the ground contact portion 4 and the chime portion 7. 2(D), the can support member 10 moves axially downward, and when the upper end surface of the stripper 20 reaches the same position as the upper end of the annular side wall 15 of the can support member 10, the upper end surface of the stripper 20 supports the grounding portion 4 of the can bottom. This allows the can body 1 to be removed from the can support member 10, and the can body 1 can be easily fed to the next stage of necking processing by a transfer star wheel (not shown).

[0018] (Seamless can manufacturing method) The method for producing a seamless can of the present invention includes at least a can body forming step and a necking step, and an important feature of the necking step is that the necking process is performed with the above-mentioned can support member being used to support and fix the grounding portion and chime portion of the can bottom from the outside of the can. That is, as described above, by supporting the can body with the can support member of the present invention in the necking process, not only the grounding portion of the can bottom but also the chime portion is supported by a surface that matches the shape of the chime portion, so that even if a load is applied in the axial direction of the can body, deformation of the chime portion can be effectively prevented. Also, because the can body is supported in the axial and horizontal directions from the outside, the necking process can be performed while the can body is firmly supported and fixed without wobbling, so that the necking process can be performed efficiently and reliably.

[0019] As described above, a plurality of slits are formed in the annular side wall, and the stripper wheel is provided with a stripper that does not interfere with these slits. This makes it possible to easily feed can bodies from the transfer star wheel to the can support member, place the can bodies on the can support member and push them into the necking tool, remove the can bodies from the can support member, and feed them to the transfer star wheel.

[0020] Furthermore, in the manufacturing method of the present invention, in addition to the can forming step and the necking step, conventionally known steps in the manufacturing method of seamless cans may be included as necessary, such as a trimming step, a cleaning step, a printing step, a flanging step, etc. Although not limited thereto, it is preferable that the steps are performed in the following order: can forming step, trimming step, cleaning step, printing step, necking step, and flanging step. In addition, in the manufacturing method of the present invention, it is particularly preferable to provide a bottom reforming step before the necking step. That is, in the bottom reforming step, in order to improve the pressure resistance of the can bottom of a thin-walled can body, in particular, a pressing body is inserted into the can body and the bottom of the can body is pressed by a forming die installed on the outer surface side of the can body, thereby bending the inner peripheral wall inward in the can radial direction to form an annular curved end portion having a grounding portion. However, the chime portion is also formed as a gently concave curved surface as well as the curved end portion, and has a shape that is prone to deformation during molding. Therefore, when the can body is supported using the can support member of the present invention, even if the chime portion has such a shape, it has an annular side wall having an inner surface that matches the shape of the chime portion, so that deformation of the chime can be effectively suppressed even when the chime portion is subjected to necking processing.

[0021] In the method for producing a seamless can of the present invention, any method may be used in the conventional method for producing a seamless can, except that the necking process is carried out using the above-mentioned can support member in the necking step. For example, as the can body forming process, a conventionally known method such as drawing, drawing / deep drawing, drawing / ironing, drawing / bending / stretching / ironing, etc. can be used. Furthermore, the shape of the seamless can is not limited to the shape shown in FIG. 1 as long as the bottom shape is as described above. Seamless cans of various shapes, such as so-called bottle cans having a neck with a significantly reduced diameter and a screw portion, can be manufactured. Furthermore, the metal sheets constituting the seamless can may be any metal sheet that has been used in the past for seamless cans, such as surface-treated steel sheets and aluminum alloy sheets, but it is particularly preferable to use aluminum alloy sheets, which are easily deformed due to thinning. These metal sheets may be resin-coated metal sheets that are coated with a thermoplastic resin such as polyester resin. When such resin-coated metal sheets are used, it is possible to omit the outer surface painting process and the inner surface painting process.

[0022] (Seamless can manufacturing equipment) According to a further important feature of the present invention, in an apparatus for manufacturing seamless cans having at least a can body forming means, a necking means, and a conveying means connecting each of the means, the necking means is provided with a can support member capable of supporting and fixing the bottom of the can body conveyed from the conveying means, and the can support member is a can support member capable of supporting and fixing the grounding portion and chime portion of the can bottom from the outside of the can.

[0023] Fig. 3 is a diagram for explaining an example of the necking means in the manufacturing apparatus of the present invention, showing one station of the necking process performed in multiple stages, and for convenience of explanation, showing a state in which there is no can body and the drive shaft has moved to the necking tool side (the position when the can body is subjected to the necking process). In the specific example shown in Figs. 1 and 2 above, the can support member is arranged so that the can axial direction is the up-down direction in the drawing, but as shown in Fig. 3, the can support member may of course be installed in an apparatus in which the can axial direction is horizontal, and it goes without saying that this can be appropriately changed depending on the arrangement of each means in the manufacturing apparatus, the conveying method, etc.

[0024] In one example of a necking means shown in FIG. 3, a necking tool generally designated 30, a star wheel 40 having a plurality of pockets 41 formed therein for holding the can body, three can support members 10, and a stripper wheel 50 for positioning the stripper 20 are provided. As shown in Fig. 1, the can support member 10 comprises a drive shaft 12 that can move in the can axial direction, and a can support part 13 attached to the tip of the drive shaft 12. A flat part 14a of a holding part 14 of the can support part 13 supports the ground contact part of the can bottom and the inner surface 15a (chime part) of the annular side wall 15. However, the structure of the can support member 10 is not limited to this, and the can support part 13 and the flat part 14a may be composed of a single part, or may be composed of a single part integrated with the drive shaft 12. A hole 51 is formed in the stripper wheel 50 to position the can support member 10 so that it can move in the can axial direction, and the stripper 20 is attached to the periphery of this hole 51. Although the stripper 20 is detachably attached to the stripper wheel 50 in Fig. 3, it may be formed integrally with the hole 51.

[0025] As shown in Fig. 2, the stripper 20 is formed at a position that coincides with the slit 16 formed in the annular side wall 15 of the can support member 10 in the can axial direction, and is formed so as not to interfere with the slit 16 when the can support member 10 moves in the can axial direction. That is, when the can support member 10 moves upward in Fig. 2 and the stripper 20 moves relatively below the flat surface 14a, the can body 1 is supported by the can support member 10 and the grounding portion is supported by the flat surface 14a of the can support portion 13. In this state, the open upper portion of the can body 1 is pushed into the necking tool 30 by the can support member 10, and the can body is subjected to the necking process. After the necking process is completed, when the can support member 10 moves downward in Fig. 2 and the stripper 20 moves into the slit 16, the can body 1 is supported by the upper end surface of the stripper 20 and is in a state in which it can be separated from the can support member 10, and while being supported by the star wheel 40, it is transferred to a transfer star wheel (not shown) and is supplied to the next necking means.

[0026] In the seamless can manufacturing apparatus of the present invention, except that the necking means is equipped with the above-mentioned can support member of the present invention, various means such as trimming means, cleaning means, printing means, necking means, and flanging means used in conventional seamless can manufacturing apparatuses can be employed as necessary. In the seamless can manufacturing apparatus of the present invention, although not limited thereto, it is preferable that the means for forming a can body, trimming means, cleaning means, printing means, bottom reforming means, necking means, and flange processing means are arranged in this order, and that a conveying means is provided between each means. [Explanation of symbols]

[0027] 1 seamless can, 2 bottom, 3 body, 4 ground portion, 5 inner wall, 6 dome portion, 7 chime portion, 10 can support member, 11 base, 12 drive shaft, 13 can support portion, 14 holding portion, 15 annular side wall, 16 slit, 20 stripper, 30 necking tool, 40 star wheel, 50 stripper wheel.

Claims

1. A can support member for supporting and fixing a can body in a can-making process, The can body is a seamless can having a body and a bottom, the bottom having at least a ground portion and a tapered chime portion that is continuous with a lower end of the body and has an outer diameter that increases upward in the can axial direction, A can support member that supports the ground portion and the chime portion from outside the can.

2. 2. The can support member according to claim 1, further comprising: a can support part including a retaining part that abuts against the grounding part to receive the bottom of the can; and an annular side wall that extends from a peripheral edge of the retaining part and has an inner surface that abuts against the chime part; and a movable shaft that moves the can support part in the can axial direction.

3. 3. The can support member according to claim 2, wherein the annular side wall is formed with a plurality of slits extending in the axial direction of the can and from the upper end to the lower end of the annular side wall, and a stripper is provided on a stripper wheel to separate the can body from the can support portion without interfering with the slits.

4. 3. The can support member according to claim 1, wherein the can body has a dome portion protruding inwardly in the can body center at the bottom, and an inner circumferential wall extending downward in the can axial direction from the outer circumferential edge of the dome portion and curving inwardly in the can radial direction, and the grounding portion is located at a lower end of the inner circumferential wall and a lower end of the chime portion.

5. A method for producing a seamless can comprising at least a can body forming step and a necking step, a can support member that supports and fixes the grounding portion and the chime portion of the can bottom from outside the can in the necking step, the can support member being used to perform the necking process.

6. 6. A method for manufacturing a seamless can according to claim 5, further comprising a bottom reforming process prior to the necking process, in which a pressing body is inserted into the inside of the can body and a forming die installed on the outer surface side of the can body is used to press the bottom of the can body, thereby curving the inner peripheral wall radially inwardly to form an annular curved end portion having a ground contact portion.

7. An apparatus for manufacturing seamless cans, comprising at least a can body forming means, a necking means, and a conveying means connecting the respective means, the necking means is provided with a can support member capable of supporting and fixing the bottom of the can body transported from the transport means, the can support member being capable of supporting and fixing the ground portion and chime portion of the can bottom from outside the can.

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