JP7496860B2 - Bottle can body, bottle can body with cap, and method for capping bottle can body - Google Patents

Description

This invention relates to a bottle can body, a bottle can body with a cap, and a method for capping a bottle can body.

A bottle can body is known as a can body in which beverages or other contents are filled and sealed, and has a can body (wall) and a can bottom (bottom), and a shoulder part with a reduced diameter on the opening side. A mouth part is formed at the tip of the shoulder part of such a bottle can body for attaching a cap that plugs the opening. A screw cap that is screwed into a thread groove formed in the mouth part is known as a cap that plugs the bottle can body (see, for example, Patent Document 1).

However, when opening a screw-capped bottle can, the screw cap must be rotated so as to break a cut portion called a bridge portion formed on the edge of the screw cap. This rotational action may not be preferred, and a bottle without a screw may be required.

Meanwhile, a pull-tab type cap (an easily openable cap) is known as a cap for a bottle can body that is easy to open (see, for example, Patent Document 2). This pull-tab type cap is attached to the mouth part of the bottle can body by forming a curled part by curling the end part of the mouth part of the bottle can body outward, and bending the edge part of the cap so as to wrap around the curved surface of the curled part.
To open the bottle, the user simply pulls the pull tab upward so as to cut off the edge of the cap that is engaged with the bottle can body, allowing the bottle to be easily opened.

Japanese Patent No. 4908544 Patent No. 5323757

In the case of a bottle can body compatible with the pull-tab type cap shown in Patent Document 2, the edge of the cap is wrapped around and locked to the curled portion that forms the opening of the bottle can body, so the winding diameter of the curled portion needs to be large enough to allow the edge of the cap to be wrapped around it. However, if the winding diameter of the curled portion is increased, the strength of the curled portion decreases. For this reason, there was a concern that the curled portion would be deformed by the stress when wrapping the edge of the cap. In addition, since it is difficult to narrow the outer periphery of the cap when the curled portion is made large, there was also a concern that the sealing ability would decrease when plugging a thin-walled bottle can body.

This invention was made in consideration of the above-mentioned circumstances, and aims to provide a bottle can body, a bottle can body with a cap, and a method for capping a bottle can body, on which an easily openable cap with excellent sealing properties can be attached without deforming the curled portion that forms the opening of the bottle can body.

In order to solve the above-mentioned problems, the bottle can body of the present invention is a metal bottle can body having a body portion formed in a cylindrical shape centered on a can axis, a bottom portion closing one end of the body portion, a shoulder portion extending from the other end of the body portion so as to reduce in diameter, and a mouth portion extending from the shoulder portion toward an opening of the other end, the mouth portion having a curl portion formed by winding the other end of the mouth portion outwardly, a neck portion connected to the shoulder portion, and a connecting portion extending to connect the curl portion and the neck portion, the connecting portion having a cross section perpendicular to the can axis that is a perfect circle at any position between the neck portion side and the curl portion side, the connecting portion having a cap locking portion on the neck side that engages with a seaming portion formed on an edge of a cylindrical extension portion that extends to cover the connecting portion in a cap that closes the opening of the mouth portion, and a cap locking portion on the front side that engages with a seaming portion formed on an edge of a cylindrical extension portion that extends to cover the connecting portion in a cap that closes the opening of the mouth portion, The can has a cylindrical portion on the curled portion side of the cap locking portion, the cylindrical portion having a circumferential surface parallel to the can axis, occupying at least half of the length of the connection portion along the can axis, and having a constant inner and outer diameter over the entire range of the circumferential surface's length along the can axis , the lower end of the cylindrical portion being connected to the cap locking portion, and the cylindrical portion being a portion of the mouth portion having a maximum diameter, the curled portion having a radius of 1.0 mm or more and 3.0 mm or less in a horizontal direction perpendicular to the can axis and a radius of 1.5 mm or more and 5.0 mm or less in a vertical direction parallel to the can axis, and the connection portion has a tapered portion on the curled portion side of the cap locking portion, the tapered portion having a diameter that decreases toward the curled portion side, and the tapered portion is inclined at an angle of 30° to 50° with respect to the can axis, and is formed so that the angle of inclination with respect to the can axis increases stepwise toward the curled portion side .

According to the bottle can body of the present invention, the position of the seaming part that engages the cap with the bottle can body is a cap locking part that is separate from the curled part of the bottle can body via a connection part, which eliminates the need to wrap the edge of the cap around the curled part to engage it, making it possible to reduce the winding diameter of the curled part.

By reducing the winding diameter of the curled portion in this way, the strength of the curled portion can be increased, and even if the mouth portion of the bottle can body is made of a thin metal plate, the curled portion will not deform or collapse. Therefore, by narrowing the outer periphery of the cap, the adhesion between the inner surface of the cap and the curled portion can be increased, making it possible to reliably seal the liquid contained in the bottle can body.

Here, the cap locking portion may be formed of a step portion that widens the neck side of the connection portion outward toward the curled portion. Furthermore, the curled portion may have a flat portion that is parallel to the can axis.

The connection portion may have a tapered portion that is closer to the curled portion than the cap locking portion and that is tapered toward the curled portion. As described above, by forming the seaming portion that engages the cap with the bottle can body at a position separate from the curled portion of the bottle can body, the inclination angle of the tapered portion with respect to the can axis can be reduced, that is, the tapered portion can be made closer to parallel to the can axis when such a tapered portion is provided. This increases the strength of the tapered portion in the direction along the can axis compared to, for example, a screw-cap type bottle can, making it possible to prevent problems such as the mouth portion buckling along the can axis when the mouth portion is molded with a die. It is preferable that the tapered portion is inclined at an inclination angle of 30° to 50° with respect to the can axis.

Furthermore, the connection part may have a cylindrical part centered on the can axis, closer to the curled part than the cap locking part. By forming such a cylindrical part, when internal pressure is applied to the bottle can body as a capped bottle can body, the vicinity of the top surface of the cap that deforms due to the internal pressure can be separated from the seaming part that engages with the cap locking part, so that the pressure resistance can be effectively increased. In addition, the inclination angle of the cylindrical part of the connection part with respect to the can axis can be set to 0°, making it possible to more reliably prevent buckling of the mouth part.
Furthermore, the length of the cylindrical portion along the can axis may be equal to or greater than half of the length of the connecting portion along the can axis.

Furthermore, when such a cylindrical portion is provided at the connection portion, the cylindrical portion may be formed with an annular groove into which the extension portion of the cap that covers the connection portion is partially fitted, the annular groove being formed so as to be connected around the can axis. By partially fitting the extension portion of the cap into such an annular groove, the cap can be firmly engaged with the mouth portion together with the seaming portion that engages with the cap locking portion, thereby further increasing the pressure resistance of the capped bottle can body and the mounting strength of the cap.

The bottle can body with a cap of the present invention is characterized by comprising the bottle can body described above and the cap in which the seaming portion engages with the cap locking portion to close the opening of the mouth portion.

In particular, when the connection part of the bottle can body has a cylindrical part centered on the can axis, and an annular groove into which an extension part of the cap that covers the connection part is partially fitted is formed so as to be connected to the cylindrical part around the can axis, the pressure resistance strength of the capped bottle can body and the attachment strength of the cap can be further increased as described above by providing the cap with the cap locking part engaged with the seaming part and the cap with the extension part partially fitted into the annular groove to close the opening of the mouth part. Note that in order to ensure the sealing of the bottle can body, it is preferable that a cap liner is sandwiched between the inner surface of the cap and the curled part.

Furthermore, the method for capping a bottle can body of the present invention is a method for capping a bottle can body as described above, which is characterized in that while applying a load toward the top surface of the cap using a pressure block, the edge of the top surface is drawn and molded using a drawing die, and the edge of the cap is rolled and tightened using a forming roller to form a tightening portion, which is then engaged with the cap locking portion.

According to this method of capping a bottle can body, the tightening roller (hem rolling roller) of a capping device used in the manufacture of a screw-cap type capped bottle can body is used as the forming roller, and the tightening part for engaging the cap with the bottle can body is formed in the cap locking part below the curl part, so that the bottle can body can be capped with the cap.

Furthermore, in this capping method, if the connection part of the bottle can body has a cylindrical part centered on the can axis, and this cylindrical part is formed to have an annular groove into which the extension part of the cap that covers the connection part is partially fitted so as to be connected around the can axis, a pressure block may be used to apply a load toward the top surface of the cap, while a drawing die may be used to draw and form the edge part of the top surface, a forming roller may be used to form a rolled-up part by rolling up the edge part of the cap and lock it into the cap locking part, and a groove-inserting roller may be used to partially fit the extension part of the cap into the annular groove.

According to this capping method, for example, the tightening roller (hem rolling roller) of a capping device used in manufacturing a bottle can body with a screw cap type cap is used as the forming roller, and a thread cutting roller is used as the groove inserting roller, and the cap is engaged by these cap locking parts and the annular groove, thereby further improving the pressure resistance strength of the bottle can body with a cap and the attachment strength of the cap.

As described above, the present invention provides a bottle can body, a bottle can body with a cap, and a method for capping a bottle can body, to which an easily openable cap with excellent sealing properties can be attached without deforming the curled portion that forms the opening of the bottle can body.

1 is a perspective view of the exterior of a bottle can with a cap according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view taken along the axis of the bottle can body of the embodiment shown in FIG. 1 . FIG. 2 is an enlarged cross-sectional view of the periphery of a mouth part of the capped bottle can body of the embodiment shown in FIG. 1 . FIG. 3 is a cross-sectional view showing an example of a capping device that engages a cap with the bottle can body of the embodiment shown in FIG. 2 . FIG. 5 is a side view of a bottle can body according to a second embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the periphery of a mouth portion of a capped bottle can body of a third embodiment of the present invention in which a cap is attached to the mouth portion of the bottle can body of the embodiment shown in FIG. 5 . FIG. 11 is a side view of a bottle can body according to a third embodiment of the present invention. FIG. 8 is an enlarged cross-sectional view of the periphery of a mouth part of a capped bottle can body of a fourth embodiment of the present invention in which a cap is attached to the mouth part of the bottle can body of the embodiment shown in FIG. 7 . FIG. 8 is a cross-sectional view showing an example of a capping device that engages a cap with the bottle can body of the embodiment shown in FIG. 7 .

Below, a bottle can body, a bottle can body with a cap, and a method for capping a bottle can body according to embodiments of the present invention will be described with reference to the drawings. Note that each embodiment shown below is specifically described to provide a better understanding of the gist of the invention, and does not limit the present invention unless otherwise specified. Also, the drawings used in the following description may show essential parts enlarged for the sake of convenience in order to make the features of the present invention easier to understand, and the dimensional ratios of each component may not necessarily be the same as in reality.

(Bottle can body, bottle can body with cap: First embodiment)
Fig. 1 is an external perspective view showing a bottle can body with a cap according to a first embodiment, and Fig. 2 is a cross-sectional view taken along the axis of the bottle can body according to the first embodiment.
The capped bottle can body 10 of the first embodiment is composed of the bottle can body 11 of the first embodiment and a pull-tab type cap 12 capable of plugging the opening P of the bottle can body 11.

The bottle can body 11 is made entirely of metal, for example an aluminum alloy, and has a body 21 formed into a cylindrical shape with a circular cross section centered on the can axis O, a bottom 22 that closes one end (lower end) of the body 21, a shoulder 23 that extends from the other end (upper end) of the body 21 so as to reduce in diameter, and a mouth part 24 that extends from the shoulder 23 toward an opening P at the other end of the bottle can body 11.

In this embodiment, the body 21, bottom 22, shoulder 23, and mouth 24 are integrally formed from a single aluminum alloy plate. For example, an aluminum alloy plate having a thickness of 0.270 mm to 0.370 mm is cupped using a cupping press, and then drawn and ironed (DI) to form a bottomed cylinder (DI can) with the body 21 and bottom 22, and then the shoulder 23 and mouth 24 are formed using a necking machine equipped with a die processing tool (neck forming die).

The outer periphery of the bottom 22 tapers downward as it approaches the inner periphery, and the bottom surface 22a of the inner periphery is curved in a dome shape toward the inside of the bottle can body 11. The shoulder portion 23 is connected to the other end of the body 21 and is formed into a truncated cone shape centered on the can axis O, which is continuously tapered as it approaches the other end of the bottle can body 11 along the can axis O, and is formed into a smoothly sloping, narrowed shape.

FIG. 3 is an enlarged cross-sectional view of the periphery of the mouth portion 24 of the capped bottle can body 10 of the first embodiment.
The mouth portion 24 is a portion connected to the other end of the shoulder portion 23, and engages with a pull-tab type cap 12 described later. The mouth portion 24 includes a curled portion 31 formed by curling the other end of the mouth portion 24 outward by a curling process, a straight neck portion 32 (cylindrical with the can axis O as its center) connected to the shoulder portion 23 and parallel to the can axis O, and a connecting portion 33 extending to connect the curled portion 31 and the neck portion 32. The connecting portion 33 includes a cap locking portion 34 on the neck portion 32 side that engages with a seaming portion 44 formed by seaming a lower edge portion of an extension portion 43 that extends to cover the connecting portion 33 in the cap 12 that closes the opening P of the mouth portion 24.

The straight neck portion 32 parallel to the can axis O has one end connected to the shoulder portion 23 and forms a cylindrical shape with a diameter φ1 (see FIG. 2) of, for example, about 25.0 mm to 40.0 mm and a length L1 along the can axis O of, for example, about 5.0 mm to 50.0 mm.
The neck portion 32 may be tapered at an angle of 0° to 10° in the vertical direction. Furthermore, the tapered shape is not limited to a linear tapered shape, and may be a curved shape or a combination of a curved line and a linear shape.

The curled portion 31 has a generally elliptical shape with a radius (winding diameter) φ2 in a horizontal direction perpendicular to the can axis O of, for example, about 1.0 mm to 3.0 mm, and a radius (winding diameter) φ3 in a vertical direction parallel to the can axis O of, for example, about 1.5 mm to 5.0 mm. The radius of curvature r1 of the upper end of the curled portion 31 is about 0.2 mm to 0.8 mm.
A flat portion 31f parallel to the can axis O is formed by throttling on the outer periphery of this curled portion 31. The length L2 of the flat portion 31f parallel to the can axis O is, for example, about 1.0 mm to 3.5 mm.

Further, the connection portion 33 is provided with a tapered portion 33a, which is closer to the curled portion 31 than the cap locking portion 34 in this first embodiment and has a diameter that decreases from the cap locking portion 34 side toward the curled portion 31 side.
The tapered portion 33a is inclined outwardly at a constant angle θ relative to the can axis O in the range of 30° to 50° as it approaches the cap locking portion 34. It is more preferable that the inclination angle θ of the tapered portion 33a be in the range of 43° to 48°. The length L3 of the tapered portion 33a from the lower end of the curled portion 31 in the direction along the can axis O is, for example, about 2.0 mm to 10.0 mm.

The cap locking portion 34 in the first embodiment is configured with a step portion 35 formed by widening the end of the connection portion 33 on the neck portion 32 side outward toward the curled portion 31 side.
The stepped portion 35 is formed to have a width W1 in the horizontal direction perpendicular to the can axis O of, for example, about 1.5 mm to 3.5 mm. The stepped portion 35 is tapered so as to be slightly inclined toward the curled portion 31 (the upper end side) from the end of the neck portion 32 toward the end of the tapered portion 33a.
The lower edge of the cylindrical extension 43 of the cap 12 is wound and fastened along the stepped portion 35 (cap locking portion 34 ) having such a shape, thereby forming a wound portion 44 .

The cap 12 plugs the opening P of the mouth portion 24 of the bottle can body 11, and is entirely made of metal, for example, an aluminum alloy.
The cap 12 has a disk-shaped top surface 41 that covers the opening P of the mouth portion 24, a bent portion 42 that extends from the outer edge of the top surface 41 and bends in contact with the curled portion 31, a cylindrical extension portion 43 that extends downward (toward the cap locking portion 34) parallel to the can axis O so as to cover the outside of the connection portion 33 (tapered portion 33a), and a seamed portion 44 that seams the lower edge of the extension portion 43. In addition, between the top surface 41 and the bent portion 42 of the cap 12, a step 45 having a step along the can axis O is formed by narrowing the outer periphery of the top surface 41 of the cap 12.

The plate thickness t of the cap 12 is, for example, about 0.22 mm to 0.30 mm. The length (height) h between the top surface 41 of the cap 12 and the seaming portion 44 is, for example, about 3.5 mm to 15.0 mm, or about 10.0 mm to 18.0 mm.
Furthermore, the seamed portion 44 of the cap 12 is formed when the opening P of the bottle can body 11 is plugged, and is formed by placing the cap 12 before the seamed portion 44 is formed on the mouthpiece portion 24 of the bottle can body 11, and then using a capping device to seam the lower edge portion of the extension portion 43 of the cap 12 along the step portion 35 (cap locking portion 34). The method of capping the bottle can body will be described later.

In addition, a pull tab 46 (see FIG. 1) is formed on a portion of the circumference of the cap 12 so as to protrude below the tightening portion 44. By pulling up the ring portion 46a, the pull tab 46 cuts open a portion of the tightening portion 44, disengaging the tightening portion 44 from the cap locking portion 34, and further breaks the cap 12 from the extension portion 43 to the bent portion 42, thereby removing the cap 12 from the mouthpiece portion 24 and exposing the opening P. The pull tab 46 forms a pair of linear grooves 46b, 46b in the tightening portion 44 and extension portion 43 connected to the pull tab 46, thinning this portion, and cuts open a portion of the tightening portion 44 and extension portion 43 by a predetermined width along these grooves 46b, 46b.

Furthermore, a cap liner 47 is sandwiched between the inner surface of the top surface 41 of the cap 12 and the curled portion 31. This cap liner 47 is a packing that keeps the space between the mouthpiece portion 24 and the cap 12 liquid-tight around the opening P. The cap liner 47 is made of, for example, a resin sheet. This cap liner 47 is disposed on the inner surface of the cap 12 before capping, which will be described later, or is attached by heat fusion or adhesive, and is compressed by capping, and its outer periphery is sandwiched between the step portion 45 of the cap 12 and the flat portion 31f of the curled portion 31.

With the bottle can body 11 and the capped bottle can body 10 configured as described above, the position of the tightening portion 44 that engages the cap 12 with the bottle can body 11 is located at a step portion 35 (cap locking portion 34) separate from the curled portion 31 of the bottle can body 11 and separated from the curled portion 31 via the connection portion 33, eliminating the need to wrap the edge of the cap 12 around the curled portion 31 to engage it, thereby making it possible to reduce the winding diameter of the curled portion 31.

By reducing the winding diameter of the curled portion 31 in this way, the strength of the curled portion 31 can be increased, and even if the mouth portion 24 of the bottle can body 11 is formed from a thin aluminum alloy plate material, the curled portion 31 will not deform or collapse. Therefore, the outer periphery of the cap 12 can be squeezed with a predetermined load to increase the adhesion between the inner surface of the cap 12, the cap liner 47, and the curled portion 31, making it possible to reliably seal the liquid contained in the bottle can body 11.

In addition, when the connection portion 33 has a tapered portion 33a that narrows from the cap locking portion 34 side toward the curled portion 31 side as in this embodiment, the position of the tightening portion 44 that engages the cap 12 with the bottle can body 11 can be formed at a step portion 35 (cap locking portion 34) separate from the curled portion 31 of the bottle can body 11, thereby reducing the inclination angle of the tapered portion 33a with respect to the can axis O, that is, making it closer to parallel to the can axis O. This increases the strength of the tapered portion 33a in the direction along the can axis O compared to, for example, a screw-cap type bottle can, and prevents problems such as the mouth portion 24 buckling along the can axis O when the mouth portion 24 is molded with a die.

When the connection portion 33 thus includes a tapered portion 33a, it is desirable that the tapered portion 33a be inclined at an inclination angle θ in the range of 30° to 50° with respect to the can axis O, as in this embodiment. If the inclination angle θ exceeds 50°, there is a risk of buckling occurring during molding of the mouthpiece portion 24, while if the inclination angle θ is below 30°, the length L3 of the tapered portion 33a along the can axis O must be increased, which in turn requires that the length (height) h of the cap 12 must also be increased, which is uneconomical.

In addition, in this embodiment, the cap locking portion 34 is formed by a step portion 35 that widens the neck portion 32 side of the connection portion 33 outward toward the curl portion 31 side, so that the tightening portion 44 can be securely tightened and engaged with the cap locking portion 34 (step portion 35), and the cap 12 can be stably attached to the base portion 24.

When the step 35 is tapered from the end of the neck 32 to the end of the connection 33, as in this embodiment, so as to be slightly inclined toward the other end (upper end) of the bottle can body 11, it is preferable that the inclination angle α (see FIG. 3) relative to the direction perpendicular to the can axis is in the range of 35° to 55°. If the inclination angle α is larger than this, it may be difficult to ensure sufficient attachment strength and pressure resistance of the cap 12, while if the inclination angle α is smaller than this, it may be difficult to form the bottle can body 11, and cracks may occur.

Furthermore, in the bottle can body 11 of this embodiment, the curled portion 31 of the mouth portion 24 has a flat portion 31f parallel to the can axis O, and when forming the step portion 45 in the cap 12, a cap liner 47 is sandwiched between the flat portion 31f and the step portion 45, making it easier to ensure airtightness. In particular, in a positive pressure can in which internal pressure is applied inside the bottle can body 11, the cap liner 47 sandwiched between this flat portion 31f and the step portion 45 can reliably ensure airtightness even if the internal pressure rises.

(Method of capping a bottle can body: First embodiment)
Next, a first embodiment of a method for capping a bottle can body of the present invention for engaging a cap with a bottle can body will be described.
FIG. 4 is a cross-sectional view showing an example of a capping device for engaging a cap with a bottle can body.
When the cap 12 is seamed to cap the bottle can body 11 of the first embodiment shown in Figures 1 to 3, for example, a capping device 60 shown in Figure 4 is used. This capping device 60 includes a pressure block 61 that presses downward the top surface 41 of the cap 12 placed on the bottle can body 11, a drawing die 62 that is formed around the pressure block 61 and that draws the outer periphery of the top surface 41 of the cap 12 to form a step portion 45, and a seaming roller (forming roller) 63 that seams the edge of the cap 12 to form the seaming portion 44 at the cap locking portion 34 (step portion 35).

The pressure block 61 is provided with a pressing body 65 that presses the top surface 41 of the cap 12 and is connected to a pressure shaft 67 via a biasing spring 66, so that when the cap 12 is attached, the pressing load that presses the top surface 41 of the cap 12 placed on the nozzle portion 24 can be changed according to the size of the aperture of the nozzle portion 24.
The tightening roller 63 is rotatably supported by a support arm 68 and can rotate around the bottle can body 11 and the cap 12 around the can axis O.

When using this type of capping device 60 to engage (cap) the cap 12 with the bottle can body 11, first, the mouth portion 24 of the bottle can body 11 is covered with the cap 12 (a cup-shaped cap material before the formation of the seaming portion 44) with a cap liner 47 already disposed or attached to the inner surface.

Then, a pressure block 61 is used to apply a predetermined load toward the top surface 41 of the cap 12, while a drawing die 62 is used to draw and form the edge of the top surface 41, forming a step 45. At the same time, a tightening roller (forming roller) 63 is rotated and rotated around the can axis O along the periphery of the lower edge of the extension 43 of the cap 12, and is brought close to and into contact with the lower edge.

As a result, the lower edge of the extension 43 of the cap 12 is bent inward along the cap locking portion 34 (step portion 35) of the mouth portion 24 of the bottle can body 11, forming the seamed portion 44. Through the above steps, the cap 12 is seamed around the mouth portion 24, and a capped bottle can body 10 can be obtained in which the bottle can body 11 is sealed with the cap 12.

According to the above-described method for capping a bottle can body, the tightening portion 44 for engaging the cap 12 with the bottle can body 11 is formed in the step portion 35 (cap locking portion 34) below the curl portion 31, and the bottle can body 11 can be capped (sealed) with the cap 12.

The method for capping the bottle can body 11 of this embodiment uses a capping device used to cap a bottle can body with a screw-type cap, and does not use a thread-cutting roller to form the threads, so it can be easily and efficiently applied to the manufacturing process of a bottle can body with a screw-type cap equipped with such a capping device. The method for capping the bottle can body of the first embodiment can also be applied to the capping of the bottle can body of the second embodiment described below.

(Bottle can body, bottle can body with cap: Second embodiment)
FIG. 5 is a side view of a bottle can body according to the second embodiment of the present invention, and FIG. 6 is an enlarged cross-sectional view of the periphery of the mouth part of the capped bottle can body according to the second embodiment of the present invention.
In this second embodiment and in a fourth embodiment described later, the same parts as those in the first embodiment are given the same reference numerals, and detailed explanations thereof will be omitted. In the drawings of the second and third embodiments, the reference numerals for the dimensions and inclination angles shown in Figs. 2 and 3 are also omitted, but the numerical ranges of the first embodiment are applied unless otherwise explained.
In the capped bottle can body 70 and the bottle can body 71 of the second embodiment, the connection portion 33 is characterized by having a cylindrical portion 72 centered on the can axis O, located closer to the curled portion 31 than the cap locking portion 34.

The length L4 of the cylindrical portion 72 in the direction along the can axis O is, for example, 5.0 mm to 15.0 mm, and the inner and outer diameters are constant within this range of length L4, and it occupies most of the length of the connection portion 33, more than half, as shown in Figures 5 and 6. In the second embodiment, the length from the opening P of the mouth portion 24 to the intersection ridge between the cap locking portion 34 and the neck portion 32 is also longer than in the first embodiment, and in such a case, the length (height) h of the cap 12 is increased to about 10.0 mm to 18.0 mm as described above. In addition, in this embodiment, a tapered portion 33a that narrows toward the curled portion 31 is formed between the cylindrical portion 72 and the curled portion 31, and this tapered portion 33a is tapered in multiple steps (two steps in this embodiment) in which the inclination angle θ with respect to the can axis O increases stepwise toward the curled portion 31.

In the bottle can body 71 and the capped bottle can body 70 of the second embodiment, as in the first embodiment, the winding diameter of the curled portion 31 is reduced to increase the strength, which of course prevents deformation and crushing. In particular, in the case of the capped bottle can body 70, in which the bottle can body 71 is a positive pressure can in which internal pressure is applied, a large gap can be secured between the vicinity of the top surface 41 of the cap 12, which is deformed by this internal pressure, and the rolled portion 44, which engages with the cap locking portion 34 (step portion 35), so that pressure resistance can be effectively increased.

In addition, because the inclination angle θ of this cylindrical portion 72 with respect to the can axis O is 0°, it has high strength against loads in the direction along the can axis O, and it is possible to reliably prevent buckling or deformation of the mouth portion 24 due to the load from the pressure block 61 in the capping device 60 during capping or the load from the drawing die 62 during drawing.

(Bottle can body, bottle can body with cap: third embodiment)
FIG. 7 is a side view of a bottle can body according to the third embodiment of the present invention, and FIG. 8 is an enlarged cross-sectional view of the periphery of the mouth part of the capped bottle can body according to the third embodiment of the present invention.
This third embodiment can be said to be a modified example of the second embodiment described above, and is characterized in that, whereas the cylindrical portion 72 of the second embodiment had constant inner and outer diameters within the range of its length L4, the capped bottle can body 80 and the bottle can body 81 of this third embodiment have an annular groove 82, into which the extension portion 43 of the cap 12 covering the connection portion 33 is partially fitted, formed in the cylindrical portion 72 of the connection portion 33 so as to be connected in a circular path around the can axis O.

In this embodiment, the annular groove 82 has a substantially V-shaped cross section along the can axis O as shown in FIG. 8, but the groove bottom 82a is formed in a concave curved cross section such as a concave arc, and the connection between both wall surfaces 82b of the V-shape and the outer circumferential surface of the cylindrical portion 72 is formed in a convex curved cross section such as a convex arc. In the cross section along the can axis O, the groove depth d from the outer circumferential surface of the cylindrical portion 72 to the groove bottom 82a is, for example, in the range of 0.3 mm to 1.0 mm, and the groove width w between the intersection points Q of the extension lines of the outer circumferential surface of the cylindrical portion 72 and both wall surfaces of the V-shaped annular groove 82 is, for example, in the range of 2.0 mm to 4.0 mm. Furthermore, the center of the annular groove 82 in the can axis O direction in this embodiment is located slightly toward the opening P of the mouth portion 24 from the position of 1/2 the length L4 of the cylindrical portion 72 in the can axis O direction.

In the third embodiment, the bottle can body 80 and the bottle can body 81 with the cap are similar to the second embodiment in that when internal pressure is applied to the bottle can body 80 with the cap, the pressure resistance and the mounting strength of the cap 12 are increased, and buckling and deformation during capping can be prevented. Furthermore, the extension 43 of the cap 12 covering the connection portion 33 is partially fitted into the annular groove 82 to form an annular protrusion 48 that engages with the annular groove 82. This, together with the engagement between the cap locking portion 34 and the tightening portion 44 of the cap 12, makes it possible to attach the cap 12 to the mouthpiece portion 24 more firmly, and the pressure resistance can be further improved. The annular groove 82 may have a U-shaped or semicircular cross section.

(Method of capping a bottle can body: second embodiment)
Next, a second embodiment of the method for capping a bottle can body of the present invention for engaging a cap with the bottle can body of the third embodiment will be described.
Fig. 9 is a cross-sectional view showing an example of a capping device 90 for engaging the cap 12 with the bottle can body 81 of the third embodiment, and the same reference numerals are used for the parts common to the capping device 60 shown in Fig. 4, and the description thereof will be omitted. Also, in the capping device 90 shown in Fig. 9, the parts for processing the top surface 41 of the cap 12, such as the pressure block 61 and the drawing die 62 of the capping device 60 shown in Fig. 4, are not shown.

That is, the capping device 90 used in the method for capping the bottle can body 81 of the second embodiment includes, in addition to the parts for processing the top surface 41 of the cap 12, such as the pressure block 61 and the drawing die 62 (not shown), a tightening roller (forming roller) 63 for forming the tightening portion 44 in the cap engagement portion 34 (step portion 35) similar to the capping device 60 used in the capping method of the first embodiment, and a groove inserting roller 91 for partially fitting the extension portion 43 of the cap 12 into the annular groove 82 formed in the cylindrical portion 72 of the bottle can body 81. As this groove inserting roller 91, a thread cutting roller of a capping device used in manufacturing a screw-cap type capped bottle can body can be used.

In the capping method of the second embodiment using such a capping device 90, as in the capping method of the first embodiment, a load is applied to the top surface 41 of the cap 12 using a pressure block 61, while the edge of the top surface 41 is drawn by a drawing die 62 to form a step 45, and the tightening roller (forming roller) 63 is rotated around the can axis O along the periphery of the lower edge of the extension 43 of the cap 12, bringing them into close contact with each other, and this lower edge is bent inward along the cap engagement portion 34 of the mouth portion 24 to form the tightening portion 44.

In the capping method of the second embodiment, in addition to processing the top surface 41 of the cap 12 and forming the seaming portion 44, the groove-cutting roller 91 is rotated and rotated around the can axis O, and is pressed inwardly toward the extension 43 of the cap 12 at the position where the annular groove 82 of the bottle can body 81 is formed, and the extension 43 at this position is partially deformed into a convex shape to follow the cross section of the annular groove 82 and fitted into the annular groove 82 to form the annular protrusion 48 described above. In the manufacturing process of the screw-cap type bottle can body with a cap, since the helical male thread portion is formed in the mouth portion, the thread-cutting roller moves in the can axis direction while rotating around the can axis, but since the annular groove 82 is connected by rotating around the can axis O, the groove-cutting roller 91 does not move in the can axis O direction.

Therefore, in the capping method of the second embodiment, a capping device used for capping a bottle can body with a screw-type cap is used to form the tightening portion 44 using the tightening roller (hem rolling roller) 63 as a forming roller, and the thread cutting roller is used as a groove inserting roller 91 to form the protrusion portion 48 that is partially fitted into the annular groove 82 on the extension portion 43 to perform capping. Therefore, like the capping method of the first embodiment, it can be easily and efficiently applied to the manufacturing process of a bottle can body with a screw-type cap equipped with such a capping device.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their variations are within the scope of the invention and its equivalents as set forth in the claims, as well as within the scope and gist of the invention.

Next, the effects of the bottle can body and the capped bottle can body of the first, second and third embodiments will be described with examples of the present invention. In this example, based on the first, second and third embodiments, ten bottle can bodies 11, 71 and 81 for 300 ml were manufactured from an aluminum alloy plate material with an original plate thickness of 0.345 mm. The diameter of the body 21 is 66 mm, the height in the can axis O direction from the bottom 22 to the opening P is 133 mm, the diameter φ1 of the neck 32 is 36 mm, the inside diameter of the opening P is 31 mm, the width W1 of the cap locking portion 34 in the horizontal direction perpendicular to the can axis O is 1.2 mm, and the inclination angle α is 47°. These are referred to as Examples 1 to 3, respectively.

In Example 1, the inclination angle θ of the tapered portion 33a was 45°, and the length along the can axis O from the opening P to the intersecting ridge between the cap locking portion 34 and the neck portion 32 was 9 mm. Meanwhile, in Examples 2 and 3, the length along the can axis O from the opening P to the intersecting ridge between the cap locking portion 34 and the neck portion 32 was 17 mm, and the length L4 of the cylindrical portion 72 along the can axis O was 10 mm. In Example 3, the groove depth d of the annular groove 82 was 0.7 mm, and the groove width w was 3.5 mm.

Next, the mouth portions 24 of the bottle can bodies 11, 71, and 81 of Examples 1 to 3 were capped with caps 12, which were also made from aluminum alloy plate material and had a plate thickness t of 0.25 mm, a length (height) h between the top surface 41 and the seaming portion 44 of 17.7 mm, and an outer diameter of the extension portion 43 of 38 mm, based on the capping methods of the first and second embodiments described above, to produce ten each of the capped bottle can bodies 10, 70, and 80 of Examples 1 to 3.

Then, holes were drilled in the bottom 22 of the bottle can bodies 11, 71, and 81 of the capped bottle can bodies 10, 70, and 80 of Examples 1 to 3, compressed air was supplied, and the pressure when the cap 12 was removed by the internal pressure was measured. The average value was calculated for ten pieces of each of Examples 1 to 3 to compare the pressure resistance.

As a result, while the average value for Example 1 based on the first embodiment was 0.42 MPa, Example 2 based on the second embodiment had a pressure resistance of 0.88 MPa, which was almost double the average, and Example 3 based on the third embodiment had a pressure resistance of 1.23 MPa, which was almost three times the average of Example 1. From these results, it was demonstrated that the pressure resistance is higher in the cylindrical portion 72 than in the tapered portion 33a on the curled portion 31 side of the cap locking portion 34 of the connection portion 33, as described above, and in particular, the pressure resistance is even higher when the cylindrical portion 72 is formed with an annular groove 82 into which the extension portion 43 of the cap 12 is partially fitted.

REFERENCE SIGNS LIST 10, 70, 80 Bottle can body with cap 11, 71, 81 Bottle can body 12 Cap 21 Body 22 Bottom 23 Shoulder 24 Mouthpiece 31 Curled 31f Flat 32 Neck 33 Connection 33a Tapered 34 Cap locking portion 35 Step 41 Top 43 Extension 44 Seaming portion 45 Step 46 Pull tab 47 Cap liner 48 Protrusion 60, 90 Capping device 61 Pressure block 62 Drawing die 63 Seaming roller (forming roller)
72 Cylindrical portion 82 Annular groove 91 Grooving roller O Can axis θ Inclination angle of tapered portion 33a with respect to can axis O

Claims (6)

A metal bottle-can body having a body portion formed in a cylindrical shape centered on a can axis, a bottom portion closing one end of the body portion, a shoulder portion extending from the other end of the body portion so as to reduce in diameter, and a mouth portion extending from the shoulder portion toward an opening at the other end,
the base portion includes a curl portion formed by outwardly curling the other end of the base portion, a neck portion connected to the shoulder portion, and a connection portion extending to connect the curl portion and the neck portion,
the connection portion has a cross section perpendicular to the can axis that is a perfect circle at any position between the neck portion side and the curled portion side,
the connection portion is provided with, on the neck portion side, a cap locking portion that engages with a seaming portion formed on an edge of a cylindrical extension portion of a cap that closes the opening of the mouth portion so as to cover the connection portion, and a cylindrical portion that is provided on the curl portion side of the cap locking portion and forms a circumferential surface parallel to the can axis, occupies half or more of the length of the connection portion along the can axis, and has a constant inner and outer diameter over the entire range of the circumferential surface's length along the can axis ,
a lower end of the cylindrical portion is connected to the cap locking portion, and the cylindrical portion is a portion that forms a maximum diameter of the base portion,
The curled portion has a radius in a horizontal direction perpendicular to the can axis of 1.0 mm or more and 3.0 mm or less, and a radius in a vertical direction parallel to the can axis of 1.5 mm or more and 5.0 mm or less,
the connecting portion includes a tapered portion that is located closer to the curled portion than the cap locking portion and that is tapered toward the curled portion,
The bottle can body is characterized in that the tapered portion is inclined at an angle of 30° to 50° with respect to the can axis, and is formed so that the angle of inclination with respect to the can axis increases stepwise toward the curled portion . The bottle can body according to claim 1, characterized in that the cap locking portion is a stepped portion that widens the neck side of the connection portion outward toward the curled portion. The bottle can body according to claim 1 or 2, characterized in that the curled portion has a flat portion parallel to the can axis. 4. A bottle can body with a cap, comprising: the bottle can body according to claim 1; and the cap, the cap engaging portion being engaged with the seaming portion to close the opening of the mouth portion. 5. The bottle can with a cap according to claim 4 , wherein a cap liner is sandwiched between the inner surface of the cap and the curled portion. A method for capping a bottle can body, comprising the steps of: attaching a cap to the bottle can body according to any one of claims 1 to 3 ;
A method for capping a bottle can body, characterized in that a load is applied toward the top surface of the cap using a pressure block, while a drawing die is used to draw and form the edge of the top surface, and a forming roller is used to roll and form a seamed portion by rolling the edge of the cap, and engage it with the cap locking portion.

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