JP2002302137A - Metallic di can with screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metallic DI can with screws wherein a bridge cut of a cap can be prevented and a cap opening torque is minimized. SOLUTION: In the metallic DI can 10 with screw threads, external screw threads 14 are formed on the outer periphery of a mouth 13, and the effective number of threads of the threads 14 is 2 for the majority thereof. Further, the effective number of turns of the threads 14 may be 1.5-2.0. Thus, a bridge cut of the cap attached to the mouth 13 can be avoided. Further, by improving the coating material of the external threads, a cap opening torque can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a threaded metal DI can, and more particularly, to a threaded metal can provided with a male screw around the mouth of the can and sealing the mouth with a cap. The present invention relates to improvement of a male screw of a DI can.

[0002]

2. Description of the Related Art In recent years, metal cans having male threads around the mouth are filled with beer, low-malt beer, carbonated beverages, soft drinks, and other beverages, and the mouth is closed with a cap and can be freely opened and closed. Many canned beverages have been sold. As one type of metal cans used for such beverages in metal cans, a metal laminated with a polyethylene phthalate (PET) resin material, for example, an aluminum strip is used. After shaping the cylindrical body so that the bottom part becomes the bottom, the tip of the part was cut into a mouth, a male screw was formed on the outer periphery of the mouth, and the bottom part of the can was separately formed There is a type in which a bottom plate is crimped and attached to a cylindrical body (hereinafter, this type of metal can is referred to as a threaded laminated metal can). Other types include non-laminated metals,
For example, there is a threaded metal DI can formed by using a conventional manufacturing process of a metal DI can formed by squeezing an aluminum strip. On the other hand, as shown in FIG. 1, a cap 1 for sealing a metal can with a screw as described above includes a main body 2 having a top plate 3 and a plurality of bridges 5 circumferentially separated by slits 4. And a hem 6 on the open end connected to the main body through the cap 1. When the metal can is sealed with the cap 1, the hem is wrapped around the skirt of the metal can by the hem winding step. Then, when the cap is opened, a torque is applied to the main body of the cap to cut the bridge 5.

[0003] In the meantime, the above-mentioned metal can with screw, both a laminated metal can and a metal DI can, are usually formed by deep-drawing a material made of aluminum strip, and the thickness of the can is thinned. For this reason, beer, happoshu,
Liquid nitrogen is added after filling the beverage to raise the internal pressure of the can above atmospheric pressure, not only when filling a beverage mixed with gas, such as carbonated beverages, but also when filling a beverage mixed with no gas. Pressure is applied to prevent the can from crushing. Moreover, in the case of a wide-mouthed metal can, the force acting on the cap outward from the inside of the can is larger than that of a narrow-mouthed metal can. For this reason, there is a problem that one or a plurality of bridges are naturally cut after the can is sealed with the cap, that is, a so-called bridge break occurs. If a bridge break occurs, it cannot serve as evidence of bridge opening.

[0004] As a method of solving such a problem of the breakage of the bridge, a method of increasing the strength of the bridge, for example, increasing the width of each bridge or increasing the number of bridges can be considered. In any of the methods for raising the cap, there is a problem that the rotational force required to be applied to the cap at the time of opening the cap, that is, the opening torque increases, and it becomes difficult to open the cap. Alternatively,
Although it is conceivable to reduce the load on the bridge by increasing the number of effective screw turns, this also has a problem of increasing the opening torque. Furthermore, the external thread formed at the mouth of the metal can for beverages is limited due to the restriction on forming the metal can itself.
There are other points to consider, such as the depth of the cap, the pitch of the screw, and the shape of the thread.

[0005]

The inventors of the present invention have conducted intensive studies on the mechanism of the occurrence of bridge breakage in a threaded metal DI can, and as a result, most of the bridge breaks are in a sealed metal DI can. Came to discover that the thread of the male screw at the mouth of the mouth occurred in a single part, and got the idea that it is possible to eliminate the bridge break by improving the structure of the male screw, The invention has been completed.

SUMMARY OF THE INVENTION It is an object of the present invention to minimize the opening torque so that the bridge can be prevented from breaking while maintaining easy opening without increasing the width of the bridge of the cap or increasing the number of bridges. Metal D with screws
To provide I-cans. Another object of the present invention is to increase the number of effective screw turns of the external thread of the mouth,
Threaded metal DI that can further improve the opening torque by improving the coating material of the external thread portion
Is to provide cans.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a metal strip-shaped can material is deeply formed to form a cylindrical body, and an opening of the cylindrical body is formed by forming an opening having a male thread. In the above-mentioned metal DI can with a screw, the number of effective screws of the male screw is set to 2 in a circumferential direction range where a majority of the bridge of the cap exists. Further, the number of effective screws in the male screw may be set to be larger than 1.5 and smaller than 2 as the number of turns of the screw. By configuring the threaded metal DI can as described above, it is possible to prevent breakage of the bridge while maintaining easy opening without increasing the width or the number of bridges of the cap, thereby minimizing the opening torque. be able to.

In the above-mentioned threaded metal DI can, a metal strip-shaped can material is deeply formed to form a cylindrical body,
In a threaded metal DI can formed by molding an opening of the cylindrical body into a male threaded mouth, the cylindrical body in which the threaded mouth is formed before molding the threaded mouth. The outer periphery of the opening may be coated with a polymerized polyester / amino resin, and a polyethylene wax may be added to the polymerized polyester / amino resin.
By doing so, the opening torque can be further improved.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a wide-mouthed metal can with a screw according to the present invention. FIG.
In one embodiment of the present invention, a threaded metal DI
The right half of the can 10 is shown in cross section. Metal D with screw
The I can 10 has a bottom portion 11, a tubular portion 12 formed integrally with the bottom portion, and a mouth portion 13 formed at an end of the tubular portion (an end opposite to the bottom portion). ing. The mouth portion 13 has a smaller diameter than the cylindrical portion 12 and has an external thread 14 formed on the outer periphery thereof. The process for manufacturing such a threaded metal DI can is briefly described as follows.

First, a can material, which is a thin strip of aluminum (non-laminated material), is deeply formed into a cylindrical portion 12 with a bottom 11 as shown in FIG. The open end is trimmed at a desired distance from the bottom as shown in FIG. 3B. Thereafter, when a decoration such as a pattern is provided on the outer periphery of the metal can, which is the final product, after performing processes such as washing and undercoating, such a pattern is printed on the outer periphery of the cylindrical portion 12 (up to this point). Is the same as the method of manufacturing a normal metal DI can), and a coating material is applied to the outermost surface of the tubular portion 12 and dried to protect the printing surface. Next, after the inner surface processing step of the tubular portion 12 is completed, necking is performed on the opening of the tubular portion 12 to form the mouth portion 13 as shown in FIG. 3C. Furthermore, as shown in FIG. 3D at the lower end of the mouth portion 13,
After the skirt portion 15 is formed, a screw forming process is performed as shown in FIG.
The male screw 14 is formed as shown in FIG. Finally, curling of the opening edge 16 of the mouth, that is, the top surface is performed, and FIG.
As shown in [F], it is formed into a final shape, and becomes a final product 10 through a secondary washing and drying process.

The threads of the male screw 14 formed on the outer periphery of the mouth portion 13 as described above are formed at a thread pitch of eight threads per inch, and as shown in FIG. Are not two peaks, and part A is one peak. Expressing this state as the effective number of turns of the screw thread is 1.7 turns. Thus, the fact that the effective number of turns is 1.7 means that the number of threads is two in the area of 70% of the outer periphery of the mouth, and the remaining 30%.
Indicates that the number of threads is one only in the region of. In this embodiment, the number of bridges is eight, and the number of effective screw turns is 1.7 in which the number of effective screws is 2 in the circumferential direction where the majority of the bridges exist. However, the present invention is not limited to this. The number of effective screw turns can take a value in the range of more than 1.5 turns and less than 2.0 turns depending on the number of turns. Also,
When a metal can as a product is sealed with a cap, in order to improve the sliding between the metal can and the cap when opening the cap, and to prevent the opening torque (rotational force applied to the cap required to open the cap) from increasing. In the above-mentioned coating material application step, a resin obtained by adding a polyethylene wax to a polymerized polyester / amino resin was applied as a coating material.

When the mouth portion 14 of the metal DI can 10 with a screw made as described above is sealed with a cap on the lid portion, it can be performed by a conventional capping device, that is, a capper. As shown in FIG. 5, the conventional capper 50 is supported by a capper body (not shown) so as to be movable up and down.
A pressure block 51 for pressing the cap 1 covered from above on the top, and a center axis Y- of the pressure block supported by the capper body via a support shaft 57.
Two threading rollers 55 arranged opposite to each other in the diameter direction of a circle centered on Y, and also supported by the capper body via a support shaft 58, and centered on the center axis YY of the pressure block. And two hem windings 56 that are arranged in the diameter direction of the circle and are shifted by 90 ° in the circumferential direction. The pressure block 51 has an inner part 52 that pushes the top plate 3 of the cap 1 from above toward the edge of the mouth of the metal DI can, and a cylindrical part 53 arranged on the outer peripheral part of the inner part. . The thread cutting roller 55 and the skirt winding roller 56 simultaneously rotate about an axis YY and are rotatable about their own rotation axis yy. The threading roller 55 and the hem winding roller 56 are
And 58 move radially inward and outward about axis YY, or by supporting shafts 57 and 58
Swings about the upper end, so that the axis Y-Y
Can be moved inward and outward in the radial direction around the center. Further, each of the threading rollers 55 is independently movable in the vertical direction relative to the pressure block 51, and the two hem winding rollers 56 are simultaneously moved in the vertical direction. .

When performing the capping process with the above-mentioned capper, the capping process is performed twice with the same capper as follows. In the first capping process, first, FIG.
As shown in [A] and [B], cover the mouth portion 13 with the cap 1 and press the pressure block 51 of the capper 50.
Is lowered from above the cap, and the top plate 3 of the cap is pressed toward the mouth of the metal DI can by the inner portion 52, and the sealing member disposed in the cap is moved to the opening edge 1 of the mouth.
6 is pressed. When the pressure block descends, the lower end edge of the outer cylindrical portion 53 projects below the inner portion 52, so that the periphery of the top plate 3 of the cap 1 is closed by a mouth of a threaded metal DI can. According to the shape of the part 13,
It is deformed downward (FIG. 6C). After that, FIG.
As shown in FIG. 5, two threading rollers 55 and two hem winding rollers 56 of the capper 50 are simultaneously rotated along the axis Y-.
Y is turned around and the threading roller 55
And the skirt winding roller 56 is gradually moved toward the axis Y-Y. Then, the outer periphery of the main body 2 of the cap is threaded along the outer periphery of the main body 2 of the cap 1 along the shape of the external thread formed in the mouth portion 14 (here, threading is
Instead of actually performing the cutting process, the cap body is pressed with a threading roller to deform it into a thread root along the external thread of the metal can.) The portion 16 is deformed along the skirt portion of the metal DI can and a hem winding process is performed. The reason that the cap can be threaded in this way is that the threading roller not only pivots about the axis Y-Y and moves towards that axis, but also can move down along the external thread of the metal DI can. That's why. In the first capping process, approximately 60% to 70% of the entire process is performed. Then, after performing the first capping process, the cap is kept pressed by the pressure block 51, and then the second capping process is performed in the same manner as described above.
The capping process of the cap is completed.

Apart from performing capping by a conventional method using a conventional capper as described above, the following may be performed. That is, in the above-mentioned conventional capper, as shown in FIG. 7, the two hem winding rollers 56a of the capper 50a are slightly shifted in the vertical direction (the shift amount δ may be 0 <δ ≦ 1 mm). Each roller 5
5a and 56a are formed in the shape of an abacus ball such that the central portions 551a and 561a are thicker and thinner linearly toward the outer peripheral edges 552a and 562a.
2a is rounded with a radius of curvature. Here, as shown in FIG. 8, the radius of curvature R of the threading roller 55a is set to 0.7 mm ≦ R ≦ 1.1 mm. Further, when the inner diameter d of the cylindrical portion 53a of the pressure block 51a is D, the curled outer diameter of the mouth of the metal DI can 1 is D,
(D + 1) mm ≦ d ≦ (D + 3) mm. In this way, a part of the configuration of the conventional capper is improved, and the capping process is performed twice by one unit in the same manner as described above. By performing capping in this manner, the screw formed on the cap can be replaced with a threaded metal D
The male screw formed on the I can can be molded exactly, and from this point, the bridge can be further prevented from breaking.

Further, as described below, the capping process may be performed using the first and second two cappers.
The first capper used in this method is the same as that shown in FIG. 5 except that the number of threaded rollers and hem-wound rollers is different, so only the differences will be described. Is omitted. As shown in FIG. 9, the first cappers 50 b are separated from each other in the circumferential direction of the circle centered on the center axis YY (90 °).
Three threaded rollers 55b arranged (shifted one by one)
And one hem winding 5 arranged at a position where the threaded roller is not arranged on the circumference around the center axis YY.
6b. Other structures are the same as the capper of the above embodiment. The second capper is the same as the capper shown in FIG. 5, and a description thereof will be omitted.

When the capping process is performed by the two cappers, the following process is performed. In the first capping process by the first capper, first, as shown in FIGS. 10A and 10B, the cap 13 is put on the mouth portion 13 and the
The pressure block 51 is lowered from above the cap, and the top plate 3 of the cap is
Pressing toward the mouth of the can, the sealing member arranged in the cap is pressed against the opening edge 16 of the mouth. When the pressure block descends, the outer cylindrical portion 53
Of the top plate 3 of the cap 1, the lower end edge of the cap 1 protrudes below the inner portion 52.
It is deformed downward along the shape of the can mouth 14 (FIG. 1).
0 [C]). Thereafter, as shown in FIG.
Three threading rollers 55b and 1 of the capper 50b
The skirt winding rollers 56b are simultaneously turned around the axis Y-Y, and the thread cutting roller 55b and the skirt winding roller 56b are gradually moved toward the axis Y-Y. Then, the outer periphery of the main body portion 2 of the cap is threaded along the shape of the external thread formed in the mouth portion 13 by the outer periphery of the main body 2 of the cap 1 (here, the thread cutting means that the cutting is actually performed. Without pressing the main body of the cap with a threading roller to deform the cap into a threaded shape along the external thread of the metal can).
6b deforms the skirt portion 16 along the skirt portion of the metal DI can, and hem winding is performed. In the first capping process, approximately 60% to 70% of the entire process is performed. After performing the first capping process, metal D
The I can is moved to the position of the second capper, and a second capping process is performed by the second capper. The second capping is the same as the first capping, except that the thread is cut by two threading rollers and the hem winding process is performed by the two hem winding rollers, and therefore the description is omitted. Completion of the second capping process completes the cap capping process of this embodiment. By performing capping in this manner, the screw formed on the cap can be formed exactly with the male screw formed on the threaded metal DI can, and in this respect, the bridge can be further prevented from breaking.

[0017]

According to the present invention, the following effects can be obtained. (A) Bridge breakage can be prevented without increasing the width of the bridge of the cap and without increasing the number of bridges. (B) The opening torque can be minimized so that the bridge can be prevented from being broken while keeping the cap easy to open.

[Brief description of the drawings]

FIG. 1 is a side view of a cap used to seal a threaded metal DI can.

FIG. 2 is a side view showing a cross section of one side of a metal DI can with a screw to which the capping method of the present invention is applied.

FIG. 3 is a view for explaining a manufacturing process of the metal DI can with a screw of FIG. 2;

FIG. 4 is an enlarged side view of the mouth of the metal DI can with thread of FIG. 2;

FIG. 5 is a schematic perspective view of a capper that performs an embodiment of the capping method of the present invention.

6 is an explanatory diagram of a capping step performed using the capper of FIG.

FIG. 7 is a side sectional view of a modification of the capper of FIG. 5;

FIG. 8 is an enlarged cross-sectional view of a peripheral portion of a thread cutting roller and a skirt winding roller of FIG. 7;

FIG. 9 is a schematic perspective view of still another modified example of the capper.

FIG. 10 is an explanatory diagram of a capping step performed using the capper of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cap 2 Main body part 3 Top plate 4 Slit 5 Bridge 6 Hem part 10 Metallic DI can with a screw 11 Bottom 12 Cylindrical part 13 Mouth part 14 Screw 50, 50a, 50b Capper 51, 51a, 51b Pressure block 55, 55a, 55b Threading roller 56, 56a, 56b Hem winding roller

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E033 AA01 BA09 DA03 DB01 DD05 FA01 GA02 3E062 AA04 AB02 AC03 DA01 DA02 DA09 JA03 JB23 JC02 3E084 AA04 AA12 AA22 AA24 AA37 AB01 BA01 CA01 DA01 DB01 DB12 FA09 FB01 FB04 GA04 KA15 KB01

Claims (4)

[Claims] 1. A threaded metal DI can formed by deeply forming a metal strip-shaped can material to form a tubular body, and forming an opening of the tubular body into a male threaded mouth. The metal DI can with a screw, wherein the number of effective screws of the male screw is 2 in a circumferential direction range where a majority of the bridge of the cap exists. 2. The metal DI can with a screw according to claim 1, wherein the number of effective threads of said male screw is greater than 1.5 and less than 2 as the number of turns. 3. The threaded metal D according to claim 1 or 2.
In the I-can, a screw formed by coating a high molecular weight polyester / amino resin on an outer periphery of an opening of the cylindrical body in which the threaded port is formed before forming the threaded port. With metal DI can. 4. The metal DI can with a screw according to claim 3, wherein a polyethylene wax is added to the polymerized polyester / amino resin.