JP2003252321A - Mouth structure of bottle can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a mouth structure of a bottle can, which causes no deteriora tion in sealing properties even in the case where a cap is deformed by the internal pressure in the bottle can. <P>SOLUTION: The mouth structure of the bottle can is formed such that a curled part 25 is formed by folding back outwardly the periphery of a bottle can mouth 23 and that a cap liner 3 is closely contacted with an outer surface of the curled part 25. The curled part 25 has a linear part 13, which is closely contacted with the liner 3, at its outer surface side profile part in a cross section parallel with an axial line 11 of the bottle can. The linear part 13 is inclined in the direction in which it approaches the axial line 11 toward a bottom of the bottle can. Further, an angle θ given by the linear part 13 and the axial line 11 is set in the range of 1°<θ<10°. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bottle can mouth portion and a cap by bringing a cap liner attached to the inner surface of the cap into close contact with a curl portion formed by folding the periphery of the bottle can mouth portion outward. The present invention relates to a mouth structure of a bottle can that seals a container.

[0002]

2. Description of the Related Art For example, a bottle can made of an aluminum alloy material for beverages has a screw portion on the outer periphery of a mouth portion which is an upper end of a bottle neck portion. In the bottle can, after filling the product, a cap is attached to the threaded portion to seal the product. The cap first covers the mouth with the cylinder, and press-molds the cylinder along the threaded portion of the mouth to complete screw molding and mounting at the same time.

As shown in FIG. 2, a cap liner 3 as a sealing material is attached to the inner surface of the cap 1. When the cap 1 is attached to the mouth portion 7 of the bottle can,
The cap liner 3 is brought into close contact with the mouth portion 7 to enhance the sealing property with the mouth portion 7. The mouth portion 7 of the bottle can to which the cap liner 3 is closely attached is provided with a curl portion 9 formed by folding the periphery of the mouth portion 7 outward. That is, the cap liner 3 comes into close contact with the outer surface of the curl portion 9.

In the curl portion 9, a straight line portion 13 that is in close contact with the cap liner 3 is formed on the outer surface side contour portion of the cross section parallel to the axis 11 of the bottle can. Conventionally, this straight portion 13
Were formed parallel to the axis 11. Therefore, on the outer surface of the curl portion 9, a cylindrical outer peripheral surface centered on the axis 11 is formed. By providing such a straight line portion 13, the mouth portion 7 of the bottle can can secure a good sealing property with the cap liner 3, and the sealing property of the product in the bottle can can be improved.

[0005]

However, in the conventional mouth structure of the bottle can described above, when the internal pressure of the bottle can increases and the bottom plate 1a of the cap 1 is deformed in the direction of bulging outward, the cap liner 3 is , And is deformed outward from the position shown by the broken line 15 in FIG. 2 and away from the upper end of the curl portion 9, and as a result, the sealing surface between the cap liner 3 and the mouth portion 7 is reduced. At this time, a force is applied to the cap 1 in the direction of coming out of the mouth portion 7. However, in the conventional mouth portion structure of the bottle can, since the straight portion 13 provided in the curl portion 9 is formed parallel to the axis line 11, The close contact surface of the cap liner 3 is only displaced and deformed in parallel with the straight line portion 13, and there is a possibility that the sealing performance may be reduced due to the reduction of the sealing surface. Further, when the deformation amount of the cap liner 3 is large, the thickness of the cap liner 3 is reduced, and the surface pressure at the sealing portion is reduced, so that the sealing performance is more significantly reduced. In particular, in the case of a positive pressure can in which the pressure inside the bottle can is set higher than the atmospheric pressure in advance, such a problem was feared immediately after the completion of sealing the product. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mouth structure of a bottle can that does not reduce the sealing performance even if the cap is deformed by the internal pressure of the bottle can.

[0006]

In order to achieve the above-mentioned object, the mouth structure of a bottle can according to claim 1 of the present invention is
In the structure of the mouth of a bottle can, the curl is formed by folding the periphery of the mouth of the bottle to the outside, and the cap liner is in close contact with the outer surface of the curl, and the curl has a cross section parallel to the axis of the bottle. The outer surface side contour portion has a straight line portion in close contact with the liner, and the straight line portion is inclined toward the bottom of the bottle can in a direction approaching the axis.

In this mouth structure of the bottle can, the straight line portion formed on the outer surface side contour portion of the curl portion is inclined toward the bottom of the bottle can in a direction approaching the axis. That is, the outer peripheral surface of the curl portion is formed with a tapered surface whose diameter decreases toward the bottom of the bottle can. The cap liner is in close contact with the mouth so as to wrap the tapered surface from the outside. Therefore, when the internal pressure of the bottle can increases and the cap deforms in the direction of coming out of the mouth, the cap liner deforms in the direction of moving away from the tip of the mouth, but at the same time,
The cap liner that is in close contact with the curl portion is more strongly pressed against the straight portion, so that the surface pressure of the seal portion is increased and the sealing performance is enhanced. That is,
By reducing the sealing surface and increasing the surface pressure,
The sealing property will be supplemented.

According to a second aspect of the present invention, there is provided a bottle can mouth structure according to the first aspect, wherein an angle θ between the straight line portion and the axis is 1 ° <θ <10 °. It is characterized by being in the range.

In the mouth structure of the bottle can, the angle θ formed by the straight line portion and the axis line is in the range of 1 ° <θ <10 °, so that the surface pressure of the sealing portion can be kept between the sealing property and the opening property. It is the optimum range that satisfies both. That is, when the inclination angle of the linear portion is 1 ° or less, even if the internal pressure of the bottle can increases, the cap liner is not pressed against the linear portion, the surface pressure of the sealing portion does not increase, and the sealing performance is improved. Cannot be increased.
Further, when the inclination angle of the straight portion is 10 ° or more, the surface pressure of the seal portion becomes too large, the opening torque increases, and the opening performance deteriorates. On the other hand, the angle θ is 1 ° <θ <10 °
With the mouth structure of the bottle can in the range of, when the internal pressure of the bottle can rises, the surface pressure of the seal part rises in the optimum range, and it is possible to improve the sealing performance while ensuring good openability. it can.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the mouth structure of a bottle can according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is an enlarged cross-sectional view of an essential part of the mouth structure of a bottle can according to the present invention. The same members as those shown in FIG. 2 are designated by the same reference numerals. The mouth structure of the bottle can according to the present embodiment has a curl portion 25 formed by folding the periphery of the mouth part 23 of the bottle can outward. The cap liner 3 similar to the conventional one closely contacts the outer surface of the curl portion 25.

In the curl portion 25, a straight line portion 13 that is in close contact with the cap liner 3 is formed on the outer surface side contour portion of the cross section parallel to the axis line 11 of the bottle can. It is not necessary for all of the linear portions 13 to be in close contact with the cap liner 3, and at least a portion thereof may be in close contact with the cap liner 3. By providing this straight line portion 13, the mouth structure of the bottle can increases the contact area between the curl portion 25 and the cap liner 3 and secures a good sealability with the cap liner 3.

The straight portion 13 is inclined toward the bottom of the bottle can in a direction approaching the axis 11. Therefore,
On the outer surface of the curl portion 25, an outer peripheral surface of an inverted cone centering on the axis 11 is formed. That is, this outer peripheral surface is a taper surface whose diameter gradually decreases toward the bottom of the bottle can.

In the conventional mouth structure of the bottle can, since the straight portion 13 provided on the curl portion 9 shown in FIG. 2 is formed parallel to the axis 11, the cap 1 is subjected to a force in the direction of coming out of the mouth portion. At this time, only the contact surface of the cap liner 3 is displaced and deformed in parallel to the linear portion 13, and a force perpendicular to the linear portion 13 which is the sealing surface is not generated. That is, the surface pressure of the seal portion does not change. On the other hand, in the structure of the mouth portion of the bottle can according to the present embodiment, the outer peripheral surface of the curl portion 25 that is in close contact with the cap liner 3 is a tapered surface that expands in the direction in which the cap 1 comes off. When is displaced in the pull-out direction, the cap liner 3 is pressed against the tapered surface, and this pressing force causes a component force in a direction perpendicular to the linear portion 13 to increase the surface pressure of the seal portion.

Therefore, the more the cap 1 is displaced in the pulling-out direction, the closer the seal portion of the cap liner 3 is to the taper surface having the larger diameter, and the surface pressure is increased accordingly, so that the cap liner 3 becomes thicker. Will be transformed into. As a result, the internal pressure of the bottle can increases, the cap liner 3 is deformed outward and separated from the upper end of the curl portion 25, and as a result, the sealing surface between the cap liner 3 and the mouth portion 23 decreases, Cap liner 3 and straight part 13
The surface pressure with respect to each other increases, the reduction of the sealing surface is compensated, and the sealing performance is improved.

Further, the straight line portion 13 has an inclination angle set such that the angle θ formed with the axis 11 is in the range of 1 ° <θ <10 °. Thus, the angle θ formed by the straight line portion 13 and the axis 11 is in the range of 1 ° <θ <10 °,
The surface pressure of the seal portion is in the optimum range that satisfies both the sealing property and the opening property.

That is, when the inclination angle of the linear portion 13 is 1 ° or less, the cap liner 3 is not pressed against the linear portion 13 even if the internal pressure of the bottle can increases. Therefore, the surface pressure of the seal portion does not rise and the sealing performance cannot be improved. Further, when the inclination angle of the straight portion 13 is 10 ° or more, the surface pressure of the seal portion becomes too high, the opening torque increases, and the opening performance deteriorates. On the other hand, the angle θ is 1 °
With the mouth structure of the bottle can within the range of <θ <10 °, when the internal pressure of the bottle can increases, the surface pressure of the sealing part rises in the optimum range, and the sealing performance is ensured while ensuring good opening performance. It will increase the nature.

In order to manufacture a bottle can having this mouth structure, a blank plate made of an aluminum alloy material is punched into a circular shape and drawn to obtain a bottomed cylindrical cup member. Further, after re-squeezing and ironing to obtain a flat-bottomed can of a predetermined thickness, the can end opening is made into a cylindrical squeeze with an inner diameter smaller than the outer diameter of the can by necking with a diameter reducing machine Push it into the mold. As a result, a bottle shape having a predetermined length reduced from the tip opening is formed.

Then, after the neck-in process is completed, the neck portion of the bottle-shaped can whose diameter has been once reduced is expanded again by a diameter expander. The bottle-shaped can that has been subjected to the diameter-expanding process is then formed with a screw forming machine to form a threaded portion on the diameter-expanded portion at a constant distance from the opening end.

In the can having the threaded portion, the opening end is folded outward by a curl machine, and then the folded portion (curl portion 25) is crushed from the outer surface side by a slot machine to form a straight portion 13. . At this time, the outer diameter and the inner diameter of the mouth portion 23 are the same as those in the conventional case by bending only the folding piece 27 at the angle θ.

Then, in the bottle can, after the product is filled into the bottle can, the cylindrical portion to be the cap 1 is put on the screw portion,
By pressing and molding the outer periphery of this cylindrical body along the threaded portion, the screw forming and mounting of the cap 1 are completed at the same time.
Since the cap liner 3, which is a sealing material, is attached to the inner surface of the cap 1, the cap 1 is attached to the mouth portion 23 of the bottle can so that the cap liner 3 is attached to the straight portion of the curl portion 25. Close to 13 and seal the product in the bottle can.

As described above, according to the mouth structure of the bottle can described above, the straight portion 13 formed on the outer surface side contour portion of the curl portion 25 is inclined toward the axis 11 toward the bottom of the bottle can. Therefore, a taper surface is formed on the outer peripheral surface of the curl portion 25 so as to reduce its diameter toward the bottom of the bottle can, and the cap liner 3 closely contacts from the outside so as to wrap the taper surface from the outside. Therefore, even if the internal pressure of the bottle can increases and the cap 1 is deformed in the direction of coming out of the mouth portion 23 and the cap liner 3 is deformed in the direction of moving away from the tip of the mouth portion, at the same time, the cap liner that is in close contact with the curl portion 25 3 is pressed against the linear portion 13 more strongly, so that the surface pressure of the seal portion can be increased and the sealing performance can be improved.

[0022]

As described above in detail, according to the mouth structure of the bottle can of claim 1 according to the present invention, the liner is closely attached to the curl portion outer surface side contour portion having a cross section parallel to the axis of the bottle can. Since the straight line portion is formed, and the straight line portion is inclined toward the bottom of the bottle can in the direction approaching the axis,
Even if the internal pressure of the bottle can increases and the cap liner deforms away from the tip of the mouth, the cap liner that is in close contact with the curl will be pressed against the straight line more strongly, increasing the surface pressure of the seal part. Thus, the hermeticity can be improved.

According to the mouth structure of the bottle can of claim 2, the angle θ formed by the straight line portion and the axis line is 1 ° <θ <10 °.
By setting the above range, the surface pressure of the seal portion becomes the optimum range that satisfies both the sealing property and the opening property. That is, it is possible to prevent the sealing performance from deteriorating when the inclination angle of the linear portion is 1 ° or less, and to suppress the increase in the opening torque when the inclination angle of the linear portion is 10 ° or more. As a result, it is possible to realize high sealing performance while ensuring good opening performance.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a main part of a mouth structure of a bottle can according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a conventional bottle can mouth structure.

[Explanation of symbols]

3 ... Cap liner 11 ... Axis 13 ... Straight part 23 ... Mouth 25 ... Curl section θ: Angle between straight line and axis

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3E033 AA06 BA09 CA05 DA03 DA08                       DA10 FA01                 3E084 AA04 AA12 AA23 AB01 BA01                       CA01 DA01 DB12 GA01 GB01                       HA02 HB07 HD01 HD02

Claims (2)

[Claims] 1. In a bottle can mouth structure in which a curl portion is formed by folding back the periphery of a bottle can mouth portion to the outside, and a cap liner is in close contact with the outer surface of the curl portion, wherein the curl portion is an axis line of the bottle can. A bottle characterized in that it has a straight line portion in close contact with the liner on an outer surface side contour portion of a cross section parallel to, and the straight line portion is inclined in a direction approaching the axis toward the bottom of the bottle can. Can structure of the can. 2. The bottle can mouth structure according to claim 1, wherein an angle θ formed by the straight line portion and the axis line is 1 ° <θ <1.
The mouth structure of a bottle can, which is in the range of 0 °.