JP2001233332A - Can with screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably ensure sealability of each of a large number of cans with screw wherein the mouth/neck part thereof is formed integrally out of a metal sheet by a method wherein the top of an outward curled part of the mouth thereof is formed simply in flatness, and to heighten therewith the entire strength at the mouth/neck part against a vertical load applied from above. SOLUTION: For the can with screw which is made of a metal sheet by molding into a structure wherein a mouth/neck part 5 comprising an outward curled part 11 formed in a ring-like shape along the edge at the upper opening thereof, a sloped wall 12 extending downward toward the outside from the curled part 11 and a screw forming part 13 extending downward from the sloped wall 12 is formed integrally with the can, the curled part 11 crooking outwardly from the upper end of the sloped wall 12 is formed so that the top thereof becomes flat with the cut-end part of the curled part 11 rolled up into the inside and butted against the internal surface at the top of the curled part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can with a screw provided with a mouth and a neck for mounting a screw cap, and more particularly, to a metal can mainly formed of an aluminum alloy plate or a surface-treated steel plate. The present invention relates to a can with a screw in which an outer curl is formed along the upper edge of the open mouth and neck.

[0002]

2. Description of the Related Art In order to make a can container for beverage cans resealable, a can with a threaded mouth and neck is provided, and a screw cap is detachably mounted on the mouth and neck to allow the mouth and neck to be resealed. A so-called threaded can, in which the upper end opening of the part is sealed with a screw cap, has been conventionally proposed. In such a threaded can, an aluminum alloy plate or a metal sheet such as a surface-treated steel plate is used as an integral part. As a molded neck portion, a screw portion screwed with the screw portion of the cap is formed at the upper end of the neck portion formed on the peripheral surface, an inner winding or an outer winding curl portion is formed along the opening edge. The structure is conventionally known.

That is, for example, Japanese Patent Application Laid-Open No. Hei 10-5090
In Japanese Patent Publication No. 95, there is a type in which an upper lid having a mouth and neck portion is fastened to a can body in which a bottom portion and a body portion are integrally formed, and the bottom and the body portion are integrally formed. The upper and lower parts of the can body were formed by squeezing the upper part of the can body, and the bottom lid was fixedly fastened to the lower end opening of the body part of the can body in which the mouth, neck, shoulders and body were integrally formed. Various types of bottle-shaped cans, such as types, and Japanese Patent Application Laid-Open Publication No. Hei 1-210136, describe that the upper end of the body of a can body having a bottom and a body integrally formed is neck-in processed to form a mouth and neck. Regarding the wide-mouth type cans, a structure in which an inner winding or an outer winding curl is formed along the upper edge of the mouth and neck is disclosed.

[0004]

By the way, in a screw can having a curled portion formed at the upper end of the mouth and neck as described above, if the curled portion is inwardly wound, the consumer opens the can and removes the contents. When drinking a beverage, the curl portion hinders the flow of the beverage and makes it difficult to pour smoothly.In addition, when the content is swallowed and resealed with a cap, the beverage remains attached to the curl portion and remains unattended. It will be in a sanitary condition,
Since the cut end of the curled portion (cut end surface of the metal plate) is located inside the can, if the cut end of the curled portion is not particularly subjected to coating treatment, the beverage filled in the can Since there is a possibility that corrosion occurs at the cut end of the curled portion, it is desirable that the curled portion formed at the upper end of the mouth and neck portion be wound outside.

However, when the curled portion at the upper end of the mouth and neck portion is externally wound, if the outer diameter of the ring of the curled portion protrudes radially outward from the threaded portion, the threaded portion of the cap and the curled portion interfere. Since the cap cannot be detachably screwed on, the portion following the screw forming portion from the curl portion needs to be an inclined wall extending inward in the radial direction from the screw forming portion, and is therefore formed of a thin metal plate. When attaching a cap to the mouth and neck that is doing, a large vertical load acting on the curled part at the upper end of the mouth and neck from above,
By acting as a force to bend the lower inclined wall inward, the inclined wall portion is easily buckled.

That is, when a cap is attached to the mouth and neck of a screwed can, the side wall of the cap is usually rolled on the thread of the mouth and neck while pressing the cap over the mouth and neck and pressing the cap from above. Pressing and deforming the cap to form a threaded part on the cap while mounting it, or rotating the cap with a screw and a can with a screw relative to each other, or attaching the threaded cap to the mouth and neck of a threaded can A capping method of forcibly pushing in from above is adopted, and a vertical load of up to about 1275 to 1373 N acts on the mouth and neck from above regardless of which method the cap is attached to. Therefore, if the curled portion at the upper end of the mouth and neck is externally wound, such a large vertical load from above causes the inclined wall below the curled portion to buckle as described above. It Kunar's.

On the other hand, by devising the size of the curl width with respect to the thickness of the thin metal plate and the angle of the inclined wall below the curl portion, the necessary strength of the mouth and neck portion against a vertical load from above can be obtained temporarily. Although it is possible, when the strength of the mouth and neck is further increased so that it has a margin against the vertical load from above, the sloping wall below the curl part is less likely to buckle Even if the reinforcement is performed as described above, there is a problem that the curl portion itself is deformed due to the concentration of the load on the curl portion.

On the other hand, apart from the problem of the strength of the mouth and neck when the curled portion is wound outside, in a screw can having a curled portion formed at the upper end of the mouth and neck, the top of the curled portion is Due to the curved surface by curling, for example, when the seal member attached to the inner surface of the top plate of the metal cap is simply flat, the upper end of the mouth and neck is fixed at a certain height. Compared to a glass bottle or a resin bottle formed on a flat surface, the sealing performance between the cap and the upper end of the mouth and neck may be weak and uncertain, so the sealing member attached to the inner surface of the top plate of the cap It is necessary to take special measures for the shape.

[0009] In view of the above, with regard to a screw can having a curled portion formed at the upper end of the mouth and neck portion, even if the sealing member attached to the inner surface of the top plate of the metal cap is merely flat, the cap and the mouth can be used. In order to ensure the sealing performance with the upper end of the neck, for example, use of a vertical load acting on the upper end of the mouth and neck when attaching the cap as described above, or other appropriate pressing means It is conceivable that the top of the curled portion formed on the curved surface by curling is deformed by pressure from above to form a flat surface.

However, in the case where the top of the curl portion is to be deformed by a pressure from above to form a flat surface, in order to stably secure the sealing performance of each of a large number of cans to be processed, the curl portion is required. It is necessary to always deform the top part of the curl part in the same manner.In this regard, in the case of a hollow curl part whose curl width is substantially circular in vertical section, the top part of the curl part is always the same due to pressure from above. Deformation into such a flat surface is not easy in practice.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems. More specifically, the present invention relates to a threaded can in which the mouth and neck are integrally formed of a thin metal plate. Can be easily formed on the same flat surface at all times, so that the sealing performance of each of a large number of cans can be ensured stably, and the entire mouth and neck against vertical load from above It is an object to further increase the strength.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has been made by forming from a thin metal plate.
At least a mouth having an outer curl portion formed in a ring shape along the upper end opening edge, an inclined wall extending downward and outward from the curl portion, and a screw forming portion extending downward from the inclined wall. In a threaded can with a neck integrally formed, a curled portion that bends outward from the upper end of the inclined wall, the cut end of the curled portion is rolled into the curled portion, and is brought into contact with the inner surface of the top of the curled portion. In this state, the curled portion is formed so as to have a flat surface.

According to the screw can having the above structure,
When forming the upper end of the mouth and neck in the curled part of the outer winding,
First, the cut end portion of the curl portion is formed so as to be wound into a predetermined position inside the curl portion, and then a predetermined pressure is applied from above, so that the top of the curl portion is placed on the cut end portion inside the curl portion. By preventing deformation of the curl portion at the position where the inner surface abuts, the top of the curl portion can be formed as a constant flat surface, thereby stably ensuring the sealing performance of each of a large number of cans can do.

The curled portion formed as described above has such a structure that it cannot be easily deformed even if further pressure is applied from above. Therefore, the vertical section of the curled portion is simply a substantially circular shape. The curl part itself is significantly reinforced compared to some, and the inclined wall below the curl part is reinforced so that it does not easily buckle, so that the upper part is Even if the vertical load applied from above concentrates on the curled portion, the curled portion itself does not deform, and as a result, it is possible to greatly increase the overall strength of the mouth and neck portion against vertical load from above .

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a screw can according to the present invention will be described in detail with reference to the drawings. In addition,
FIG. 1 shows the whole of a bottle-type threaded can according to an embodiment of the threaded can of the present invention, and FIG. 2 shows a state before the threaded can shown in FIG. 3A to 3F schematically show a process of forming the mouth and neck of the can lid shown in FIG. 2, and FIG. 4 shows a mouth and neck of the threaded can of the present invention. FIG. 5 shows a cross-sectional structure of a curled portion at an intermediate stage when forming the curled portion shown in FIG. 4, and FIG. 6 shows a cross-sectional structure of a curled can of the comparative example. FIG. 7 shows a cross-sectional structure of a curled portion at the upper end of the mouth and neck, and FIG. 7 shows can bodies (A), (B), and (C) of each type according to another embodiment of the threaded can of the present invention. .

The threaded can 1 of this embodiment is a three-piece can (three-piece can) bottle type can body, and as shown in FIG. 1, both upper and lower open ends of a cylindrical body. A can lid 2 provided with an outlet for the content liquid is fixed to the upper end opening of the can body 3 having a neck and flange processing on each part by double winding, and the lower end opening is A closing bottom cover 4 is fixed by double winding, and a small-diameter mouth-neck portion 5 serving as a spout of the content liquid is provided on the can cover 2.
Are integrally formed.

In such a can 1 with a screw, the can body 3
Is made of a rectangular blank of surface-treated steel sheet with a synthetic resin coating on one side and a printed pattern such as a mark on the other side, and rounding the blank so that the printed pattern is on the outside and both ends The overlapped part is seam-welded by the conventional electric resistance welding method, protective coating is applied to the welded seam to form a cylindrical body, and the neck-in part and the horizontal flange part are formed at both open ends by neck and flange processing. Is formed.

The bottom cover 4 for closing the lower end opening of the can body 3
It is made of a thin metal plate having a synthetic resin film coated on both sides of an aluminum alloy plate or a surface-treated steel plate, and is integrally formed by press working so that a flange portion is formed on the outer peripheral edge. A sealing compound made of synthetic resin and rubber is applied to the flange portion serving as a fastening portion for sealing. If the synthetic resin film coated on the inner surface side of the can body 3 and the bottom cover 4 is made thick, even if a sealing compound made of synthetic resin and rubber is not applied to the flange portion, the bottom cover can be used. There is no problem in sealing the body 3 and the bottom cover 4 at the tightened portion.

The can lid 2, which is wound and fixed to the upper end opening of the can body 3, is made of a synthetic resin obtained by laminating a thermoplastic resin film on one side (the inner side of the can) or both sides of an aluminum alloy plate or a surface-treated steel plate. Using a thin metal sheet with a coating as a material, it is integrally formed into a basic shape having a mouth-neck portion whose upper end is closed by drawing in a plurality of steps, and thereafter, FIG.
The upper end of the mouth and neck is opened and a curl, a screw, and the like are formed on the peripheral wall by a forming process as shown in FIG.

The method of laminating the thermoplastic resin film on the thin metal plate used as the material of the can lid 2 is as follows.
In addition to the method of thermally bonding a thermoplastic resin film directly to the metal surface of a thin metal plate, a thermoplastic resin film is bonded via an adhesive primer layer or a curable adhesive layer or a thermoplastic resin layer having good thermal adhesion. There is a method of heat bonding to a metal surface of a thin metal plate.

The can lid 2 before being wound around the can body 3 is shown in FIG.
As shown in FIG. 3, a flange portion 8 serving as a portion to be fastened to the can body 3 is formed on the outer peripheral edge portion of the can lid 2, and inside the flange portion 8, the flange portions of the can lid 2 and the can body 3 are connected to each other. A counter-sink portion 7 into which the chuck of the double-screwing device is fitted when the double-screws are tightened is formed in an annular shape with a substantially V-shaped vertical cross section, and a shoulder portion 6 is formed inside and above the countersink portion 7. In addition, a substantially cylindrical mouth-and-neck portion 5 serving as a spout is erected upward from a central portion of a shoulder portion 6.

Although not shown, a sealing compound made of synthetic resin and rubber is usually applied for sealing on the lower surface side of the flange portion 8 whose outer peripheral edge is curled. However, if the synthetic resin film on the inner surface side of the can lid 2 and the can body 3 is made thick as in the case of the above-mentioned sealing of the can body 3 and the bottom cover 4 at the tightened portion, the synthetic resin and the rubber Even if the sealing compound consisting of is not applied to the flange portion 8, it does not hinder the sealing of the can lid 2 and the can body 3 at the tightly wound portion.

The mouth and neck portion 5 serving as a spout of the can lid 2 is formed with an outer winding curl portion 11 along the upper end opening edge so that the overall shape as viewed from above becomes a ring shape. And the inclined wall 1 facing radially outward below the curl portion 11.
2 and a screw forming portion 13 in which a screw for screwing with a screw portion of the cap is formed below the inclined wall 12. The shape of the screw formed in the screw forming portion 13 is not particularly limited, and a screw formed of a convex portion or a concave portion winding the cylindrical base of the screw forming portion 13 or a discontinuously formed screw is formed. It may be a screw consisting of a ridge or a groove, and may be either a single screw or a double screw.

An annular bead portion 14 is formed below the thread forming portion 13, and a substantially cylindrical outer peripheral surface of the bead portion 14 is tapered so as to be slightly tapered upward and approximate to a cylindrical surface. , The lower end of the bead portion 14 continues to the small-diameter cylindrical portion 15 via an inward step, and the lower end of the small-diameter cylindrical portion 15 continues to the upper end of the shoulder portion 6 via an outward step. ing.

The lower end of the bead portion 14 and the small-diameter cylindrical portion 15 following the small-diameter cylindrical portion 15 enter the small-diameter cylindrical portion 15 with the roller of the capping device (capper) when the metal cap is mounted on the mouth and neck. By pressing the lower end wall of the cap against the step at the lower end of the bead portion 14 to deform the cap, the cap is locked to the mouth and neck portion 5 in a pill fur proof state.

The steps for forming the mouth and neck portion 5 in the above structure will be described below with reference to FIGS. 3A to 3F. First, although not shown, the mouth and neck 5 are covered with a synthetic resin film. The thin metal sheet is press-formed into a cup, and then the cup is redrawn to form a flanged cup having a horizontal flange on the outer peripheral edge, and the flanged cup is gradually drawn. Thus, as shown in FIG. 3 (A), an unformed mouth and neck portion 5, a shoulder portion 6, a countersink portion 7, and a horizontal flange portion 8 are provided as shown in FIG. The can lid is integrally molded.

Then, as shown in FIG. 3B, for the can lid whose mouth and neck 5 shown in FIG. 3A is not formed, first, the end wall 17 of the mouth and neck 5 not opened is cut off. By removing
The upper end small diameter portion of the mouth and neck portion 5 is opened, and a non-circular flange portion 8 that elongates differently depending on the crystal direction of the thin metal plate or the like.
After trimming by punching into a predetermined circle,
As shown in (C), the upper opening edge of the mouth and neck portion 5 is slightly curled outward, and the outer peripheral edge of the flange portion 8 is curled downward.

Next, a mold for maintaining the inclined wall 12 formed below the small diameter portion at the upper end of the mouth and neck portion 5 in a predetermined shape is inserted into the inside of the mouth and neck portion 5 and then curled from above. By pressing down the punch, as shown in FIG. 3 (D), an outer curl portion 11 is formed at the upper end opening edge of the mouth and neck portion 5, and the inclined wall 1 extending downward from the curl portion 11 is formed.
2 is maintained in a predetermined shape.

With regard to the outer curl portion 11 formed at the upper end of the mouth and neck portion 5, in the can 1 with screw according to the present embodiment, a normal curl having a curl width as shown in FIG. Instead of being formed in a part, as shown in FIG.
The cut end 11a of the curl portion 11 is wound into the inside of the curl portion 11 and is brought into contact with the inner surface of the top portion 11c of the curl portion 11 so that the top portion 11c of the curl portion 11 is formed to be flat. Also, regarding the inclined wall 12 extending downward from the curl portion 11, the curvature radius R of the bent portion between the inclined wall 12 and the lower threaded portion 13 is 1.5 to 2.5 mm,
The inclination angle θ with respect to the horizontal plane is set to 40 to 50 °.

As described above, the outer winding curl portion 1
As shown in FIG. 3 (E), a thread forming portion 13 is formed on the mouth and neck 5 below the inclined wall 12. At this time, the method of forming the thread and the thread valley of the screw forming portion 13 includes a method of inserting a female mold into the inside of the mouth and neck portion 5 and pressing a roll from the outside, and a method of forming the inside of the mouth and neck portion 5. There is a method of forming by pressing a roll.

After forming the screw forming portion 13 in this manner, as shown in FIG. 3 (F), the mouth and neck portion 5 below the screw forming portion 13 is formed into an original cylindrical shape with an annular bead portion having a predetermined width. After the lower end of the mouth and neck portion 5 is formed into a small-diameter cylindrical portion 15 by pressing a roll from the outside below the bead portion 14 in a state where the sealing compound is made of a synthetic resin and a rubber, The edge is applied to the lower surface of the curled flange 8 and then dried and fixed.

A more specific example of the threaded can 1 of the present embodiment having the can lid 2 formed as described above will be described. As a thin metal plate used as a material of the can lid 2, for example, A film made of a copolymerized polyester of isophthalic acid, another dicarboxylic acid component and a glycol component is heat-fused to a thickness of 12 μm on both sides of an aluminum alloy plate (3004-H191) having a thickness of 0.315 mm and quenched. A film obtained by laminating films that have been made amorphous is used.

This film is a two-layer film obtained by laminating copolymerized polyester of isophthalic acid having a different melting point between the outer layer and the inner layer with another dicarboxylic acid component and a glycol component at the same thickness. When cracks occur, the cracks no longer reach the inner layer side, and the melting point of the outer layer side is higher than the melting point of the inner layer side, and the melting point of the two-layer film on the outer surface side of the aluminum alloy plate is higher. It has properties higher than the melting point of the two-layer film on the inner surface side.

In a coated metal sheet coated with a laminated film having such properties, the inner layer side of the film is more easily deformed than the outer layer side, and the inner surface side is more easily deformed than the outer surface side. The inner layer on the inner surface side, which has a larger deformation amount than the inner layer on the outer surface side, is the most easily deformed, and the entire film smoothly follows the deformation of the thin metal plate, making it difficult for the film to break.

The coated metal sheet on which the film is laminated in this way is punched into a cup having a diameter of 87 mm and a height of 16 mm, for example, and is subjected to the above-described forming step,
The overall height is 45 mm and the outer diameter of the flange 8 is 70 m
m, into a can lid 2 having the shape shown in FIG. 2 so that the depth from the flange 8 to the bottom of the counter sink 7 is 6.9 mm. About 65 mg of a sealing compound composed of rubber and rubber is applied in the flange portion 8 having a curled outer peripheral edge, and then stored at room temperature, and the solvent is air-dried and fixed.

In such a can lid 2, the mouth and neck portion 5 is formed, for example, such that the outer diameter of the small-diameter cylindrical portion 15 is 26 mm, the width (height) of the small-diameter cylindrical portion 15 is 2.4 mm, and the bead portion 14 is formed. Has an outer diameter of 27.6 mm, an outer diameter of a screw thread in the screw forming portion 13 is 27.6 mm, an outer diameter of a screw root is 26 mm, a ring inner diameter of the curl portion 11 is 19.9 mm, and a ring outer diameter is 2
4.9 mm, the sloped wall 12 below the curled portion 11 has a radius of curvature R
Is 1.5 to 2.5 mm, and the inclination angle θ with respect to the horizontal plane is 40 to 50 °.

On the other hand, the can body 3 has a thickness of, for example, 0.1 mm.
Epoxy resin paint is applied to the inside and outside surfaces of the 22mm ultra-thin tin-plated steel plate except for the weld seam, the printed pattern is applied to the outside surface, the seam is welded by the conventional method, and the inside and outside surfaces of the seam are epoxy resin. Cover with paint, form neck-in part and horizontal flange part at both open ends, about 65m in diameter
m and a height of 235 mm are used.

The bottom cover 4 has a thickness of, for example, 0.1 mm.
An epoxy resin paint is applied to the inner and outer surfaces of a chrome-plated steel sheet of 21 mm, and the curl outer diameter is about 72 mm by a conventional method.
A sealing compound made of synthetic resin and rubber is applied to a flange portion having a curled outer peripheral edge in the same manner as in the case of the can lid 2, and about 65 mg is used. Then, first, the bottom cover 4 is fixed to the can body 3 as described above by a double winding method.
Is fixed to the can body 3 by a double winding method to obtain a can with an internal capacity of 1000 cc.

By the way, in the threaded can 1 of the present embodiment including the above-described specific examples, the outer winding curl portion 11 formed at the upper end of the mouth and neck portion 5 of the can lid 2 is shown in FIG. As shown, the cut end 11a is entangled inside the curl portion 11 so that the lower end of the curl portion 11 becomes the bent portion 11b, and the cut end 11a abuts on the inner surface side of the top 11c of the curl portion 11. In this state, the top 11c of the curl portion 11 is formed to be a flat surface.

That is, in the step of forming the curled portion as shown in FIG. 3D, first, as shown in FIG. 5, the cut end 11a is bent so that the lower end of the curled portion 11 becomes the bent portion 11b. After the curl portion 11 is formed inside the curl portion 11 by forming the outer curl portion 11 so as to have a predetermined interval between the inner surface of the top portion of the curl portion 11 and the cut end portion 11a, for example, in the curl portion forming step By using a pressing tool or the like having a flat pressing surface, or by using the pressing force of the capper when attaching the cap after the can body manufacturing process is completed, the ring outer diameter of the curl portion 11 is reduced. By applying a vertical load from above and deforming the curled portion 11 so as to crush it, the top portion 11c of the curled portion 11 is formed to be a flat surface as described above. .

As described above, the top portion 11 of the outer winding curl portion 11
Since c is a flat surface, even when the seal member attached to the inner surface of the top plate of the metal cap is simply flat, a close contact area between the cap and the upper end of the mouth and neck can be secured. When the curl portion 11 is deformed to make the top portion 11c a flat surface, the cut end portion 1c is attached to the top portion 11c of the curl portion 11.
Since the deformation of the curl portion 11 due to pressure from above can be prevented at a predetermined position by bringing the can 1a into contact, the top portion 11c of each of the curl portions 11 of a large number of cans can always be formed as the same flat surface. Can, and
The sealing performance of each of a large number of cans can be stably ensured.

It should be noted that, if the outer curl portion 11 formed at the upper end of the mouth and neck portion 5 is formed such that the cross section (vertical cross section in the curl width direction) shown in FIG. 6 is substantially circular, Since the top of the curled portion is curved, for example, when the seal member attached to the inner surface of the top plate of the metal cap is merely flat, the upper end of the mouth and neck is fixed to a certain height. As compared with a glass bottle or a resin bottle formed on a flat surface of the rim, the sealing performance between the cap and the upper end of the mouth and neck becomes weaker.

On the other hand, apart from the above-mentioned problem of sealing performance, in the case of a can with a screw, when a cap is attached to the mouth and neck of the can, the mouth and neck may have a maximum of 1275 to 137 from above.
A vertical load of about 3N will be applied. However, if it is attempted to further increase the strength of the mouth and neck so as to have a margin against such a vertical load from above, the lower part of the curl portion If the inclined wall is reinforced so as to be less likely to buckle, the load is concentrated on the curled portion, so that the curled portion itself may be deformed in a curled portion having a substantially circular cross section as shown in FIG. There is.

On the other hand, the can 1 with screw of the present embodiment
Then, as shown in FIG. 4, the curl portion 11 has a structure that cannot be easily deformed even if pressure is further applied from above. Is greatly reinforced so as not to be easily deformed, so that the inclined wall 12 below the curl portion 11 is reinforced so that it does not easily buckle. It is possible to greatly increase the overall strength of the mouth and neck portion with respect to a vertical load from above without deforming 11 itself.

In this regard, the structure of the curled portion itself of the threaded can of the embodiment of the present invention having the curled portion shown in FIG. 4 and the comparative example having the curled portion shown in FIG. With the same structure (the structure shown in the above specific example) except for the difference in the above, a vertical load was applied to each of 20 cans from above until deformation occurred somewhere in the mouth and neck of the can. Then, by measuring the magnitude of the vertical load at the time of deformation, the difference in strength of the entire mouth and neck was compared.

In each of the cans of the embodiment and the comparative example, as shown in FIG. 4 and FIG. 6, the inclined wall 12 below the curl portion 11 has a bent portion between the curl portion 11 and the screw forming portion 13 thereunder. The radius of curvature R is 1.5 to 2.5 mm, and the inclination angle θ with respect to the horizontal plane is 40 to 50 °, whereby the lower inclined wall 12 of the curl portion 11 is caused by a vertical load from above. Try not to easily buckle.

As a result, in the 20 comparative examples having the curled portions shown in FIG. 6, the curled portions of the mouth and neck were deformed at 1397 to 1422 N (all of which were 1275 to 1 N).
On the other hand, it can withstand a vertical load of about 373N), whereas in the 20 examples having the curled portion shown in FIG. By making the structure of the curled portion of the outer winding as shown in FIG. 4, the mouth and neck of the can can be made to have a strength that has a sufficient margin as a whole against vertical load from above. I understood.

As another problem, in the case of a threaded can having a mouth and a neck formed with a curled portion and a threaded portion, the mouth or neck after the curled portion and the threaded portion are formed is located on the inner side or the inner side. Even if a synthetic resin film to be a protective film is applied afterwards on both the inside and outside surfaces, it is difficult to form a uniform synthetic resin film on the part where the curled part or screw part has already been formed. As a material, a metal thin plate such as an aluminum alloy plate or a surface-treated steel sheet coated with a material, it is necessary to form a curled portion or a screw portion by forming a mouth and neck portion from this coated metal thin plate, and in this embodiment, The mouth and neck portion 5 of the can lid 2 is formed of a coated metal sheet whose both surfaces are coated with a thermoplastic resin layer.

However, by forming the mouth and neck portion from such a coated metal sheet, as shown in FIGS. 3A and 3B, the end wall 17 of the unopened mouth and neck portion 5 is formed.
When the mouth and neck portion 5 is opened by cutting the sheet, a part of the thermoplastic resin layer coated on the thin metal plate may be fluffed and peeled off at the cut end.

For this reason, when the curled portion formed at the upper end of the mouth and neck portion is an outer winding, as shown in FIG. The cut end 11a in a state where the thermoplastic resin layer is not cut cleanly is seen from the outside at the lower end of the curled portion 11, and the appearance of the can is poor, and the thermoplastic resin layer is cut cleanly at the cut end 11a. Even if the metal surface exposed at the cut end 11a is rusted or corroded, such rust or corrosion can be seen from the outside at the lower end of the curled portion 11, so that the appearance of the can can also be improved. It will be bad.

On the other hand, the screw can 1 of the present embodiment
As shown in FIG. 4, the curled portion 11 of the outer winding is formed in a state where the cut end 11 a is entangled inside the curled portion 11 so that the lower end thereof is close to the inclined wall 12 as a bent portion 11 b. Curl part 1 that is visible from the outside
Since the lower end of 1 is a smooth bent portion 11b and the cut end 11a is hidden from the outside, even if the cut end 11a is unsightly, the appearance of the can is thereby deteriorated. There is nothing.

The embodiment of the threaded can according to the present invention has been described above. However, the present invention is not limited to the above-described embodiment. The part of the can except for the cap as shown in the embodiment is a three-piece can (a can composed of three parts) and is not limited to a bottle-type screw can, but is shown in FIG.
As shown in the figure, a can body (a so-called draw and redraw can or DI can) in which a can body and a can bottom are integrally formed by a well-known deep drawing method or a drawing and ironing method has a mouth-neck portion. It is also possible to use a two-piece can (a can composed of two parts) in which a can lid is fastened and fixed as a bottle-type can with a screw.

As shown in FIG. 7 (B), a two-piece can (2) in which a bottom lid is fixedly fastened to the opening at the lower end of the body of the can body in which the mouth, neck, shoulder, and body are integrally formed. (Cans composed of parts) can be implemented as bottle-type screw-type cans. Further, the present invention is not limited to bottle-type screw-type cans, and a neck-in DI as shown in FIG.
The entire can is a seamless 1 with the upper end of the can body as the mouth and neck.
Needless to say, the design can be changed as appropriate, for example, it can be implemented as a wide-mouth type screw can with a piece can (a can composed of one part).

[0054]

According to the threaded can of the present invention as described above, the top of the curled portion can always be easily formed on the same flat surface, and the cap and the upper end of the mouth and neck can be in close contact with each other. The improvement of the sealing performance by securing the area can be ensured stably for each of a large number of cans, and the curl portion itself is reinforced so that it can not be further deformed, so that it can respond to vertical load from above. The overall strength of the mouth and neck can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a side view showing the external appearance of the entire can of a three-piece can and a bottle-type can with a screw according to an embodiment of the present invention, excluding a cap.

FIG. 2 is a partial cross-sectional side view showing the can lid of the can with screw shown in FIG. 1 (before being fixedly fastened to the can body).

FIG. 3 is a cross-sectional explanatory view showing, in the order of (A) to (F), a step of forming a mouth and neck in the can lid shown in FIG. 2;

FIG. 4 is a cross-sectional view showing a structure of a curled portion at an upper end of a mouth and neck portion in the screw can of the present invention.

FIG. 5 is a cross-sectional view showing the structure of the curl portion at an intermediate stage for forming the curl portion having the structure shown in FIG.

FIG. 6 is a cross-sectional view showing a structure of a curled portion at an upper end of a mouth and neck portion in a threaded can of a comparative example.

FIG. 7 (A) A two-piece bottle type can having a can lid having a mouth and neck formed therein according to another embodiment of the screw can of the present invention, and (B) a mouth and neck, shoulder and trunk. Is a side view showing the external appearance of the entire can, excluding the cap, of each of a two-piece bottle-type can and a (C) one-piece wide-mouth type can, each of which is integrally formed and the bottom lid is fastened and fixed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 threaded can 2 can lid 5 mouth and neck part 11 curl part 11a cut end (of curl part) 11b bent part (at lower end of curl part) 11c top part (of curl part) 12 inclined wall 13 screw forming part

Claims (3)

[Claims] 1. An outer curl formed at least along an opening edge of an upper end by molding from a thin metal plate, an inclined wall extending downward and outward from the curl, and an inclined wall. In a threaded can with a mouth-and-neck portion integrally formed with a screw forming portion extending downward from the curled portion curving outwardly from the upper end of the inclined wall, the cut end of the curled portion is formed inside the curled portion. A can with a screw, wherein the top of the curled portion is formed to be a flat surface in a state where the curled portion is brought into contact with the inner surface of the top of the curled portion. 2. A thin metal plate for forming a mouth and neck portion is a coated thin metal plate having a thickness of 0.1 to 0.4 mm, wherein at least the inner surface of the can is coated with a thermoplastic resin film. The screw can according to claim 1. 3. The curved wall below the curled portion has a radius of curvature of 1.5 to 1.5 at a bent portion between the inclined wall and the threaded portion below the inclined wall.
2.5mm, the inclination angle to the horizontal plane is 40-50 °
2. The semiconductor device according to claim 1, wherein:
Or the can with screw according to 2.