JP7690765B2 - cup - Google Patents

Description

The present invention relates to a precursor cup for producing a can body for a two-piece can.

Conventionally, two-piece metal cans have been used, for example as beverage cans, and are constructed by wrapping a lid around the opening of a can body formed in a cylindrical shape with a bottom. In the process of manufacturing these two-piece cans, a short, bottomed, cylindrical cup that serves as the precursor to the can body is produced by punching and drawing a metal plate. A cupping press is generally used as a device for manufacturing this precursor cup (see Patent Document 1).

A cupping press is generally configured with multiple sets of dies (usually six or more) that punch and draw a cup in one stroke, and each die punches and draws the cup in one stroke of the cupping press, thereby producing multiple cups.

U.S. Pat. No. 3,902,347

Cups manufactured using such a cupping press may have defects due to the mold. For example, metal powder scattered in a specific mold during cup molding builds up and causes scratches on the outer surface, and if this is left unattended and continues, it can cause corrosion after filling, called ERV defects, or cause the cup to break. When a defective product occurs, it is necessary to identify the mold that manufactured the cup in question and perform repair work, but it is not easy to identify which mold caused the defect, and each mold must be inspected in turn, which takes time, resulting in a decrease in productivity.
In addition, two-piece cans are manufactured at high speed; specifically, cupping presses are operated at 120 strokes or more per minute to produce large quantities of cups in a short period of time. Therefore, by the time a defective can is discovered, a large number of two-piece cans as final products have already been produced, containing a mixture of good and defective cans. Since subsequent sorting is difficult, there is a problem that even good two-piece cans have to be discarded in large quantities.

One way to address the above-mentioned issues is to engrave numbers corresponding to each mold on the bottom of the cup, but this would require a complex mold shape, which would complicate production of the mold and increase costs, and there is also the risk of encouraging the generation and accumulation of metal powder during cup production. Furthermore, engraving the numbers is completely unnecessary for consumers and mars the aesthetic appearance. Another method could be to use a laser or other device to mark the marks inconspicuously, but there is still the problem of increased production costs for the device, such as the need to install a new laser device.

The present invention is devised to solve the above-mentioned problems, and aims to provide a cup that is low-cost and has a simple configuration, and that allows tracking of the corresponding cupping press molds in subsequent processes without compromising the appearance.

The cup according to the present invention is a cup manufactured using a cupping press that serves as a precursor for manufacturing a can body for a two-piece can in a bodymaker in a subsequent process ,
The cup is a cylindrical cup having a bottom and a body,
The bottom portion has a plurality of embossments,
The embossment is located in an area within 75% radially outward from the axial center of the cup,
The embossment is characterized in that it has a diameter of 0.3 to 0.5 mm and a height from the bottom of 1.0 mm or less.

According to the cup according to claim 1, the bottom of the cup, which is the precursor of the can body, has one or more embossments. By forming embosses in different states for each of the multiple cupping press dies on the bottom of the cup, it is possible to trace and identify the cupping press die having a problem early on from the manufactured cup, individual can bodies in the post-processing, and two-piece cans, with a low-cost and simple configuration, even if a defective product occurs due to the cupping press die.

Furthermore, according to the cup of the present invention , the embossment is positioned in an area that is 10 to 75% radially outward from the axial center of the cup, so that the embossment can be left intact and not crushed even when a ring-shaped ground contact portion or the like is formed in a subsequent process by a body maker, etc., and therefore it is possible to reliably track and identify cupping press dies that are having problems at an early stage in any of the subsequent processes.

Furthermore, according to the cup of the present invention , the embossment has a diameter of 0.3 to 10.0 mm and a height from the bottom of 1.0 mm or less, which makes it possible to track and identify cupping press dies having problems at an early stage, while preventing the embossment from being noticeable and damaging the appearance of the final two-piece can. Furthermore, since the deformation of the bottom when the embossment is formed can be kept small, the generation of metal powder in the manufacturing process can be kept to a minimum.

Furthermore, according to the cup of the present invention , by having a plurality of embossments, it is possible to easily realize, for example, forming embossments in different states for a plurality of cupping press dies on the bottom of the cup, and it is possible to easily obtain the effect of being able to track down and identify cupping press dies having problems at an early stage as described above.

Furthermore, according to the cup of the present invention , since a plurality of embossments are positioned concentrically about the axial center of the cup, the effect of being able to track and identify cupping press dies having problems at an early stage as described above can be reliably obtained, while all of the embossments can be positioned in inconspicuous positions in the final two-piece can, thereby preventing any impairment of the appearance.

According to the cupping press die of the present invention , the bottom forming surface of the cupping press die facing the surface that becomes the bottom of the cup has a convex portion for forming an embossment on the bottom of the cup, and by forming the embossment in a different state for each of the multiple cupping press dies on the bottom of the cup, it is possible to trace and identify the cupping press die having a problem early from the manufactured cup and each can body or two-piece can in the post-process, even if a defective product caused by the cupping press die occurs, with a low-cost and simple configuration. Furthermore, by providing the cupping press die itself with a convex portion for forming an embossment on the bottom of the cup, the embossment can be formed simultaneously with the drawing process for forming the cup, so that it is possible to prevent the bottom of the cup from being displaced from the desired position. Furthermore, it is possible to omit a process of forming an embossment separately, and to achieve energy saving. Furthermore, by making the embossment a protrusion with a simple structure, a detailed structure such as a number marking is not required, and therefore the complexity of manufacturing the die can be reduced.

FIG. 2 is a bottom view of a two-piece can finally obtained from the cup of the present invention. FIG. 2 is a schematic end view for explaining an example of a mold for a cupping press of the present invention.

〔cup〕
The cup according to one embodiment of the present invention is made of metal and serves as a precursor for manufacturing a can body for a two-piece can, and is a bottomed cylindrical cup having a bottom and a body.
The bottom of the cup has one or more embossments. The embossments are in different states for each corresponding cupping press mold. Having embosses in different states for each cupping press mold means that the embosses can be distinguished from each other by their number, shape, formation position, or a combination of these. For example, the number of embosses may be different between cups corresponding to each of the cupping press molds arranged in parallel.
The number, shape and formation positions of the embossments can be used to specify a corresponding cupping press die.
The number of embossments is, for example, two in the two-piece can of FIG. 1 (two embossments P circled in FIG. 1).
In the present invention, the embossment is a protrusion protruding from the inside of the cup to the outside (the front side of the paper in FIG. 1 ). The embossment is formed so as to be visible when viewed from the bottom of the can body or the two-piece can.

The position of the embossment is determined taking into consideration the shape of the bottom of the final two-piece can C, and is preferably a position that will not be crushed during the formation of the can bottom and will not impair the aesthetic appearance. Specifically, the embossment is formed at a position where it will remain uncrushed even when a ring-shaped grounding portion R or the like is formed by a body maker or the like in a subsequent process, for example, just inside the ring-shaped grounding portion R. In Fig. 1, C is the two-piece can finally obtained, and R is a ring-shaped grounding portion with a substantially U-shaped cross section that bulges out toward the can bottom so that the two-piece can C can be kept in a stable upright position when placed on a horizontal surface.
Specifically, when the radius from the axial center of the body of the cup (the center of the bottom of the cup) to the outer edge is taken as 100%, the embossment is located in an area of 10 to 75% radially outward from the center, more preferably in an area of 35 to 75%. Specifically, when the cup is used to manufacture a two-piece can with a can body diameter of 66 mm, the distance of the embossment from the axial center of the cup is set to 22.5 to 23.0 mm.
If the embossment is formed too close to the center of the bottom or too close to the outer edge of the bottom, there is a risk that the embossment will be crushed and become unrecognizable when the cup is subjected to DI processing or can bottom forming processing, or that the aesthetic appearance will be marred.
When the cup has a plurality of embossments, it is desirable that all of the embossments are located in the above range, and that each is located concentrically with respect to the axial center of the cup in the above region.

The embossment on the cup has a shape and size that allows the embossment P to remain visible even if a tool is pressed against the embossment on the bottom of the cup and it is deformed during DI processing and can bottom forming processing at a downstream body manufacturer, and is, for example, a protrusion with a diameter of 0.3 to 10.0 mm and a height from the bottom (height from the outer bottom surface) of 1.0 mm or less.
If the diameter of the embossment is too large and/or the height from the bottom is too large, the aesthetic appearance of the final two-piece can when viewed from the bottom may be impaired, whereas if the diameter of the embossment is too small or the height from the bottom is too small, the embossment may be completely crushed and become unrecognizable when the cup is subjected to DI processing or can bottom forming processing.

The plate material used to form the cup is, for example, an aluminum alloy plate material with a thickness of 0.20 mm to 0.35 mm, laminated on both sides with a PET film of about 0.01 mm.

[Cupping press die]
The cupping press die of the present invention is for producing a cup, which is a precursor for producing a can body for a two-piece can from a long sheet material, by punching and drawing the metal sheet material. In the cupping press die of the present invention, the steps of punching a substantially circular blank B from the metal sheet material, drawing it to form a cup shape, and simultaneously forming an embossment on the bottom can be performed in a single stroke.
A cupping press die 100 according to one embodiment of the present invention is comprised of a substantially cylindrical blank punch 120 having a cut end mechanism (not shown) on the outer edge of the lower end, a convex portion 130 for forming an embossment P on the bottom of a cup, a substantially cylindrical punch nose (die) 150 slidably fitted into a through hole 120H of the blank punch 120 and inserted coaxially with the blank punch 120, and a cylindrical draw pad 190 disposed below the blank punch 120 in opposition and into which the punch nose 150 can be inserted. The cut end mechanism of the blank punch 120 may have a conventionally known structure as long as it has a structure capable of punching out the blank B.
The punch nose 150 has an outer contour shape capable of drawing the blank B. The punch nose 150 has one or more protrusions 130 (one in FIG. 2 ) on a bottom forming surface 151 that faces a surface of the punch nose 150 that will become the bottom of the cup of the sheet material.
The protrusion 130 is composed of a generally cylindrical stamping portion 132 and a spacer 131 for installing the stamping portion 132 in a state in which the stamping portion 132 extends downward from a ceiling surface 153 of a disk-shaped recessed space 152 formed in the lower part of the punch nose 150, and the tip (the lower end in FIG. 2 ) of the stamping portion 132 faces the upper surface of the plate material (blank B). The stamping portion 132 is pressed against the surface of the plate material to form an embossment on the surface. The protrusion 130 may be formed integrally with the punch nose 150, or may be formed as a separate entity and fixed to the punch nose 150 by various fasteners.
It is sufficient that stamping portion 132 is provided at a position that allows an embossment to be formed at a desired position on the bottom of the resulting cup, and the protruding height of stamping portion 132 from the lowest end surface of bottom forming surface 151 (broken line in FIG. 2) varies depending on the thickness of the plate material, and it is sufficient that the desired protruding height of the emboss from the outer bottom surface of the cup is obtained. In the example of FIG. 2, the distance d from axial center X of punch nose 150, which is the axial center of the cup, to axial center Y of stamping portion 132 of convex portion 130 is 20 mm, the diameter of stamping portion 132 is 0.5 mm, and the protruding height of stamping portion 132 from the lowest end surface of bottom forming surface 151 is 0.5 to 0.7 mm.

In the example of Figure 2, only one cupping press die 100 consisting of a punch nose 150, a blank punch 120, a draw pad 190, etc. is shown, but a plurality of such die are provided spaced apart in the direction in which the long plate material extends (horizontal direction), and are configured to be able to produce a plurality of cups from a single plate material in one cycle of the cupping press.
Each cupping press die 100 is capable of forming embossments in different states from each other. Specifically, each cupping press die 100 is capable of being distinguished from each other by the number, shape, or position of the embossments, or a combination thereof.

In such a cupping press die 100, a plate material is transported and set at a predetermined position between the blank punch 120 and the draw pad 190, and the blank punch 120 is lowered, and the plate material is cut between the cut end mechanism of the blank punch 120 and the annular draw pad 190 by the relative movement between the lowering blank punch 120 and the fixed draw pad 190, and is punched out as a circular blank B. When the punched blank B is clamped between the blank punch 120 and the draw pad 190, the punch nose 150 is lowered, so that the punch nose 150 engages with the blank B, and drawing is performed into a cup having a shape corresponding to the outer contour shape of the punch nose 150. Simultaneously with the drawing, the convex portion 130 is also lowered, and the tip of the stamping portion 132 abuts against the upper surface of the blank B, and the stamping portion 132 is pressed against the blank B, so that embossing is performed by the stamping portion 132 at a predetermined position on the upper surface of the blank B, forming an emboss, and thus a cup is obtained.
The obtained cup is subjected to DI processing and can bottom forming processing at a body maker, and in these processing steps, the tool does not come into contact with the embossment on the bottom of the cup, or the tool only comes into contact with part of the embossment, so that the embossment P remains visible. Furthermore, by carrying out a conventional cleaning treatment, inner and outer surface painting, and necking and flanging, a can body having one or more embossments on the bottom surface can be manufactured.

Each of the cups and can bodies obtained in the above manner, and the two-piece can C finally obtained, has an embossment on the bottom surface as shown in FIG. 1. The number and shape of these embossments, as well as their formation position relative to the rolling direction of the plate material, differ for each corresponding cupping press die, so the corresponding cupping press die 100 can be identified based on these.

The container according to one embodiment of the present invention has been described in detail above, but one embodiment of the present invention is not limited to the above-mentioned embodiment, and various modifications can be made within the scope of the gist of the present invention described in the claims.

REFERENCE SIGNS LIST 100: Cupping press die 120: Blank punch 120H: Through hole 130: Convex portion 131: Spacer 132: Stamping portion 150: Punch nose 151: Bottom forming surface 152: Concave space 153: Ceiling surface 190: Draw pad B: Blank C: Two-piece can P: Embossed R: Ground portion X: Shaft center Y: Shaft center

Claims (2)

A cup produced by a cupping press that serves as a precursor for producing a can body for a two-piece can in a downstream body maker ,
The cup is a cylindrical cup having a bottom and a body,
The bottom portion has a plurality of embossments,
The embossment is located in an area within 75% radially outward from the axial center of the cup,
The cup is characterized in that the embossment has a diameter of 0.3 to 0.5 mm and a height from the bottom of the cup of 1.0 mm or less. 2. The cup according to claim 1, wherein said plurality of embossments are positioned concentrically about an axial center of said cup.

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