Patent Grant
11858681
This application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/JP2020/002652 filed on Jan. 27, 2020 and claims the benefit of priority to Japanese Patent Application No. 2019-11928, filed Jan. 28, 2019, all of which are incorporated herein by reference in their entireties. The International Application was published in Japanese on Aug. 6, 2020 as International Publication No. WO/2020/158634 under PCT Article 21(2).
The present invention relates to a can body having a bottle shape in which a curl part is formed on an opening part to which a cap is put on and a method of manufacturing thereof.
As a container which is filled with contents such as a beverage, known is a structure of a can body (a bottle can) made of steel or aluminum alloy on which a cap is put on an opening part to seal by a liner on an inner of the cap. In such a can body, a container is proposed which has a curl part having a shape similar to that of a bottle mouth at its opening part, and is sealed by fitting a skirt part of the cap to the curl part. The can body used for this container a relatively large curl part with respect to the opening part of the can body.
For example, International Publication No. 2007/122971 discloses a metal can in which a cap which can be opened by tearing a score by pulling a tab is seamed to be fixed on a bead part (a curl part) formed by curling a tip end of a mouth part outward. In this metal can, the mouth part extends linearly, the bead part (the curl part) is inclined inward, and an inclination start position of the bead part is set between a lower end part of the bead part and a curl start position. The curled tip part of the bead part (the curl part) abuts against an outer surface of the mouth part almost vertically.
In a metal bottle can disclosed in Japanese Unexamined Patent Application, First Publication No. 2011-116456, a curl part is formed to have a diameter-reduction part reducing in a diameter from an upper end of a mouth part, a stand-up part extending upward from an upper end of the diameter-reduction part, an upper bent part at an upper end of the stand-up part, a bent part smoothly expanding outward and extending downward from the upper bent part to protrude outward, a lower bent part at a lower end of the bent part, and a straight linear part extending linearly from the lower bent part to the diameter-reduction part. The tip end of the straight linear part abuts against an outer surface of the diameter-reduction part. It is described that an incline angle of the diameter-reduction part is 25° to 65°, a radius of curvature of the upper bent part is 0.5 to 1.0 mm, a radius of curvature of the bent part is 2.0 to 3.0 mm, a radius of curvature of the lower bent part is 0.5 to 1.0 mm, and an angle of the straight linear part with the horizontal is 0° to 25°.
Such curl part is formed relatively large with a similar shape to a bottle mouth. Therefore, the radius of curvature at the lower end of the curl part to which the skirt part of the cap is rolled in is easily increased, and pressure resistance after the skirt part of the cap is mounted may be deteriorated.
The present invention is achieved in consideration of the above circumstances, and has an object to provide a can body in which the skirt part of the cap mounted to the curl part can be reliably rolled in and fixed and the pressure resistance can be increased.
A can body of the present invention is a can body having a cylindrical part, a neck part smaller than the cylindrical part in a diameter, and a mouth part connected to the neck part. The mouth part has on an outer peripheral part thereof a curl part in which an end part including an edge is folded back outward in a radial direction and rolled up; the curl part is provided with an outer peripheral-lower side bent part which is bent inward in the radial direction at an outer peripheral lower part and convex diagonally downward in a can axis direction, a concave part which is connected to the outer peripheral-lower side bent part and concave downward in the can axis direction, and a curl end part which is connected to the concave part and includes the edge.
Since the concave part is formed between the outer peripheral-lower side bent part and the curl end part in the curl part, it is possible to reduce a radius of curvature of the outer peripheral-lower side bent part. Moreover, rigidity is high since the convex part and the concave part of the outer peripheral-lower side bent part are formed to be connected, the skirt part of the cap is favorably rolled up, and pressure resistance is improved. In addition, the concave part may not be necessarily formed in whole circumference.
As one aspect of the can body of the present invention, a radius of curvature on an outer surface of the outer peripheral-lower side bent part is preferably not less than 0.4 mm and not more than 1.2 mm, more preferably not less than 0.5 mm and not more than 0.8 mm.
By setting the radius of curvature on the outer surface of the outer peripheral-lower side bent part in this range, it is possible to certainly fix the skirt part by holding when the skirt part of the cap is rolled in.
As another aspect of the can body of the present invention, it is preferable that the curl end part have an end bent part which is gradually reduced in a diameter upward in the can axis direction from the inside of the concave part in the radial direction and curved to be convex inward in the radial direction.
The rigidity is improved since the curl end part is curved with the small radius of curvature by the end bent part; moreover, even if the curl end part is pressed against the outer peripheral surface of the mouth part starting end part by an inward external force in the radial direction when the skirt of the cap is rolled in, the edge is not easily in contact with the mouth part starting end part since the end bent part is convex inward in the radial direction, so that the mouth part starting end part is not easily damaged.
A method of manufacturing a can body of the present invention has a forming step of a small-diameter cylinder part forming a small-diameter cylinder part in a cylindrical body; and a forming step of a curl part forming a curl part which is formed by folding an end part including an edge of the small-diameter cylinder part outward in a radial direction and rounding up; the forming step of the curl part has a rolling step forming a roll part by folding the end part of the small-diameter cylinder part outward in the radial direction and rounding it, and a throttle step forming the curl part having an outer peripheral-lower side bent part which is convex diagonally downward by pressing an outer peripheral part of the roll part from the outside in the radial direction after the rolling step; and in the throttle step, a vicinity of the edge abuts an outer peripheral surface of the small-diameter cylindrical part to press inward from an outside in the radial direction, so that the outer peripheral-lower side bent part, a concave part which is connected to the outer peripheral-lower side bent part and curved to be concave downward in the can axis direction, and a curl end part which is connected to the concave part and includes the edge are formed.
Since the curl end part has the edge, it is relatively hard and not easily deformed. Therefore, pressing the roll part from the outside in the radial direction with abutting the vicinity of the edge against the outer surface of the small-diameter cylindrical part in the throttle step, so that the concave part can be formed between the curl end part which is not easily deformed and the outer peripheral-lower side bent part. Due to this formation of the concave part the radius of curvature of the outer peripheral-lower side bent part is small, so that the skirt part of the cap can firmly wrap.
As one aspect of the manufacturing method of the can body of the present invention, it is preferable to further include a pre-curling step forming a pre-curl part by folding back the vicinity of the edge of the small-diameter cylindrical part outward in a predetermined radius of curvature between the forming step of the small-diameter cylindrical part and the forming step of the curl part; and that in the rolling step, an upper part of the roll part be formed by folding back and rounding the small-diameter cylindrical part at a lower part than the pre-curl part with a larger radius of curvature than the predetermined radius of curvature.
The pre-curl part is formed with relatively a small radius of curvature, so that the rigidity of the curl end part is further improved and the concave part can be easily formed in the throttle step.
According to the present invention, it is possible to firmly fix by wrapping the skirt part of the cap attached to the curl part and improve the pressure resistance.
Below, an embodiment of a can body according to the present invention will be explained referring to drawings. A can body 100 of the present embodiment is a bottle can formed as a bottle shape in a whole as shown in
The can body 100 is made of a thin metal sheet such as aluminum or aluminum alloy, formed to be a straight shape to a middle position in a height direction as shown in
As shown in
In this embodiment, the bottom part 20 of the can body 100 has a dome part 21 arranged on the can axis C and expanding upward (toward the inside of the trunk part 10) and a heel part 22 connecting an outer peripheral of the dome part 21 and the lower end of the trunk part 10. The connection part between the dome part 21 and the heel part 22 is a ground part 23 abutting on a ground surface when arranged on the ground surface (a carrying surface) so that the can body 100 is in an upright position (a position in which the opening part 15 is upward shown in
As shown in
The neck part 13 has a shape of gradually reducing a diameter upward in the can axis; the diameter is smaller than that of the cylindrical part 11 and the upper end of the neck part 13 is the smallest diameter. A height of the neck part 13 (a dimension in the can axis direction) is slightly smaller than a height of the cylindrical part 11 (a dimension in the can axis direction). In the can body 100 of this embodiment, the neck part 13 is connected to the top end of the shoulder part 12 and has a tapered pipe shape gradually reducing in the diameter upward in the can axis direction. A top end part 13a of the neck part 13 has a small angle with the can axis C and is almost along the can axis direction (refer to
The mouth part has the curl part 50 formed on an outer peripheral part by folding outward in the radial direction an edge part including an edge. Specifically, as shown in FIG. 2, the mouth part 14 has a mouth part starting end part 41 connected to the top end part 13a of the neck part 13 and curved to swell out in the radial direction with reducing the diameter upward in the can axis direction, an inner peripheral-lower side bent part 42 curved to convex inward in the radial direction from the top end of the mouth part starting end part 41, an inner peripheral side cylindrical part 43 connected to the top end of the inner peripheral-lower side bent part 42 and extending vertically upward in the can axis direction at an innermost position of the mouth part 14, and the curl part 50 connected to the top end of the inner peripheral side cylindrical part 43 and folded outward in the radial direction. In the cross section (a vertical cross section) on the can axis C in the can axis direction, the inner peripheral side cylindrical part 43 is arranged substantially parallel to the can axis C.
The mouth part starting end part 41 swells out in the radial direction and a radius of curvature R1 (mm) of the outer surface (a convex surface) is not less than 6.3 mm and not more than 10.3 mm. The inner peripheral-lower side bent part 42 swells out in the radial direction and a radius of curvature R2 (mm) of the outer surface (a convex surface) is not less than 1.0 mm and not more than 5.0 mm.
In the curl part 50, in
The curl end part 57 is further provided with an end bent part 57a gradually reducing in the diameter upward in the can axis direction from the inside of the concave part 58 in the radial direction and bent to be convex inward in the radial direction.
The outer peripheral-lower side bent part 56 and the curl end part 57 are bent to be convex substantially downward; and the concave part 58 is formed between the outer peripheral-lower side bent part 56 and the curl end part 57 along the peripheral direction. It is not necessary for the concave part 58 to be formed continuously in the peripheral direction but it may be formed intermittently. In a case in which the concave part 58 is formed intermittently in the peripheral direction, it is a form in which the concave part 58 and a convex part 59 which is formed by continuously arranging the outer peripheral-lower side bent part 56 and the curl end part 57 are adjacent in the peripheral direction.
The folded top part 52 arranged between the inner peripheral-upper side bent part 51 and the outer peripheral-upper side bent part 53 is arranged at the peak of the curl part 50. A radius of curvature R3 (mm) of an outer surface (a convex surface) of the inner peripheral-upper side bent part 51 is not less than 0.8 mm and not more than 1.4 mm; a radius of curvature R4 (mm) of an outer surface (a convex surface) of the folded top part 52 is not less than 1.5 mm and not more than 2.5 mm; and a radius of curvature R5 (mm) of an outer surface (a convex surface) of the outer peripheral-upper side bent part 53 is not less than 2.4 mm and not more than 3.0 mm.
In this embodiment, as shown in
In the outer surface of the curl part 50, if the radius of curvature R5 of the outer peripheral-upper side bent part 53 excesses 3.0 mm, the sealing performance may be deteriorated; and if it is less than 2.4 mm, breakages and wrinkles may be generated when the curl part 50 is formed. If the radius of curvature R6 of the outer peripheral-lower side bent part 56 excesses 1.2 mm, a skirt part 202 of the cap 200 may be weakly rolled in. While, if the radius of curvature R6 is less than 0.4 mm, the breakages and the wrinkles may be generated on the curl part 50 in a forming step of 50.
The curl end part 57 is curved to gradually reduce the diameter upward in the can axis direction from the inside in the radial direction of the concave part 58 and to be convex inward in the radial direction; a radius of curvature R8 (mm) of an outer surface (a convex surface) thereof is not less than 1.0 mm and not more than 4.0 mm. In this embodiment, only the end bent part 57a of the curl end part 57 is formed to be even smaller in the radius of curvature. A radius of curvature R9 (mm) of the end bent part 57a is not less than 0.8 mm and not more than 3.0 mm. The outer surface (the convex surface) of the curl end part 57 is formed as a convex outer surface in which the curved surface with the radius of curvature R8 and the curved surface with the radius of curvature R9 are continued. The radii of curvature R8 and R9 of the curl end part 57 may be the same dimension.
Since the mouth part starting end part 41 is also curved to be convex outward in the radial direction as described above, the outer surface thereof forms a convex outer surface. Accordingly, the convex outer surface of the end bent part 57a is in contact with the convex outer surface of the mouth part starting end part 41.
The concave part 58 is formed to connect between the inside in the radial direction of the outer peripheral-lower side bent part 56 and the outside in the radial direction of the curl end part 57. On both sides (the inside and the outside) in the radial direction of the concave part 58, a convex part 59a of the outer peripheral-lower side bent part 56 which is convex downward in the can axis direction and a convex part 59b of the curl end part 57 which is convex downward in the can axis direction are formed.
A depth H of the concave part 58 in the can axis direction is a distance measured vertically from a line connecting a top point of the convex part 59a and a top point of the convex part 59b (a tangent line of the convex part 59a and the convex part 59b) in a cross section involving the can axis C, to a deepest part of an inner surface of the concave part 58. It is formed to be 0.01 mm or more and 0.30 mm or less, more preferably 0.01 mm to 0.20 mm. A radius of curvature of the convex part 59a may be the same radius of curvature as the radius of curvature R6 of the outer peripheral-lower side bent part 56; and it may also be slightly larger or smaller than the radius of curvature R6. A radius of curvature of the convex part 59b may be the same radius of curvature as the radius of curvature R8 of the curl end part 57; and it may also be slightly larger or smaller than the radius of curvature R6.
As shown in
A thickness T (mm) in the radial direction of the curl part 50 is a horizontal distance orthogonal to the can axis C from the radially-innermost position to the radially-outermost position of the curl part 50 in the radial direction. In the vertical cross section on the can axis C along the can axis direction shown in
In this embodiment, where an outer diameter of the curl part 50 is D (mm), a ratio (T/D) of the outer diameter D and the thickness T is not less than 0.07 and not more than 0.12; and the thickness T of the curl part 50 is formed in a size not less than 7% and not more than 12% of the outer diameter D. Specifically, for example, in the can body 100 in which the outer diameter D of the curl part 50 is not less than 25 mm and not more than 40 mm, the thickness T of the curl part 50 is not less than 2.0 mm and not more than 4.5 mm, preferably not less than 3.0 mm and not more than 4.0 mm. The width W of the curl part 50 is not less than 3.0 mm and not more than 5.0 mm, preferably not less than 3.5 mm and not more than 4.7 mm.
In this embodiment, as shown in
A sheet thickness of the can body 100 is not necessarily limited; an original sheet thickness of an aluminum alloy sheet before forming is 0.250 mm to 0.5 mm and the sheet thickness at the curl part 50 is 0.200 mm to 0.600 mm.
For manufacturing the can body 100 structured as above, at first, a cup 61 is formed by drawing a thin sheet of aluminum alloy or the like as shown in
Consequently, an upper part of the cylindrical body 62 is reduced in the diameter by die-necking machining, as shown in
Consequently, in the small-diameter cylindrical part 63, the curl part 50 is formed at the upper part than the part to be the inner peripheral side cylindrical part 43 by folding back an edge part including an edge of the small-diameter cylindrical part 63 to the outside in the radial direction to roll it in. This forming step of curl part has a pre-curling step of forming a pre-curl part 64 by folding back a vicinity of an edge of the small-diameter cylindrical part 63 to the outside in the radial direction with a specific radius of curvature; a rolling step of forming a roll part 65 by folding back and rounding an edge part of the small-diameter cylindrical part 63 in which the pre-curl part 64 is formed to the outside in the radial direction; and a throttle step of forming the curl part 50 having the outer peripheral-lower side bent part 56 which is convex diagonally downward by pressing an outer peripheral part of the roll part 65 from the outside in the radial direction after the rolling step. A series of machining for forming the curl part 50 is a die-necking machining to form by moving the forming tool in the can axis direction and pressing the opening end toward the can bottom.
(Pre-Curling Step)
A forming tool used in the pre-curling step is a pre-curl mold 78 provided with a guide part 76 inserted into the small-diameter cylindrical part 63 and a forming concave groove 77 formed in a ring-shape along the peripheral direction at a base end part of the guide part 76, as shown in
(Rolling Step)
In the rolling step, as shown in
The roll part 65 formed by this rolling machining has slightly a larger outline than a final shape of the curl part 50. In this stage, the pre-curl part 64 is formed at the end part of the roll part 65 and an edge is not in contact with the outer surface of the inner peripheral side cylindrical part 43.
(Throttle Step)
In the throttle step, the pre-curl part 64 including the edge is abutted on the outer peripheral surface of the small-diameter cylindrical part 63 to press it inward from the outside, so that the outer peripheral-upper side bent part 53, the concave part 58 connected to the outer peripheral-upper side bent part 53 and bent to be concave downward in the can axis direction, and the curl end part 57 which is connected to the concave part 58 and includes the edge are formed.
In the throttle step, a forming tool 74 shown in
The forming tool 74 moves on an arc line as shown by the white arrow in
By the machining of the forming tool 74, mainly the outer peripheral part of the roll part 65 is formed as shown in
That is to say, by pressing the pre-curl part 64 against the outer surface of the mouth part starting end part 41, the roll part 65 is pressed in the radial direction; as shown in
Thereby, the curl part 50 is formed in a state in which the outer surface of the end bent part 57a of the curl end part 57 is in contact with the outer peripheral surface of the mouth part starting end part 41.
The outer surface of the end bent part 57a of the curl end part 57 is curved to be convex, and the mouth part starting end part 41 is also formed to be a convex outer surface so that these convex outer surfaces are in contact with each other; therefore, forming defects are prevented such that the edge of the curl end part 57 bites the mouth part starting end part 41 or abuts against the outer peripheral surface of the mouth part starting end part 41 resulting the insufficient curl.
The can body 100 structured as above mentioned, as shown in
The cap 200 is made of a thin metal sheet of aluminum or aluminum alloy in this embodiment and has the top panel part 201 which is a round sheet shape, the skirt part 202 extending vertically downward from an outer peripheral edge of the top panel part 201, a tab 203 protruding such that it broadens a part of a lower edge of the skirt part 202 in a surface direction, and the seal material 205 formed on the inner surface of the top panel part 201 and the upper edge part of the inner surface of the skirt part 202, as shown in
In a state in which the cap 200 is mounted, the skirt part 202 wraps the curl part 50 from the bottom end of the outer peripheral side cylindrical part 54 to the bottom end of the outer peripheral-lower side bent part 56. The outer peripheral-lower side bent part 56 is provided to structure the maximum diameter part of the curl part 50; since the radius of curvature R6 thereof is small, the skirt part 202 is held on the outer peripheral-lower side bent part 56, so that the cap 200 is prevented from being off from the curl part 50.
The present invention is not limited to the above-described embodiments and various modifications may be made without departing from the scope of the present invention.
For example, the can body 100 of a circular cylindrical shape with a bottom in which the bottom part 20 and the trunk part 10 are integrally formed is explained in the above-described embodiment; however, it includes a can body without a bottom part, and a shape in which a bottom part formed separately is seamed in a trunk part after forming a curl part may be applicable.
In a can body, it is possible to fix a skirt part of a cap attached to a curl part by reliably rolling up, so that pressure resistance can be improved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-011928 | Jan 2019 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2020/002652 | 1/27/2020 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/158634 | 8/6/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4513872 | Bull | Apr 1985 | A |
| 5544808 | Aloisi | Aug 1996 | A |
| 7497350 | Enoki | Mar 2009 | B2 |
| 20040084459 | Brown | May 2004 | A1 |
| 20050115294 | Kanou et al. | Jun 2005 | A1 |
| 20120024813 | Nakagawa | Feb 2012 | A1 |
| 20200156139 | Ross | May 2020 | A1 |
| 20200172282 | Hasegawa | Jun 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 2004-175386 | Jun 2004 | JP |
| 2005-46855 | Feb 2005 | JP |
| 2011-116456 | Jun 2011 | JP |
| 2012-192984 | Oct 2012 | JP |
| WO-0138185 | May 2001 | WO |
| WO-2007122971 | Nov 2007 | WO |
| 2018211993 | Nov 2018 | WO |
| Entry |
|---|
| International Search Report dated Mar. 24, 2020 for the corresponding PCT Application No. PCT/JP2020/002652. |
| Extended European Search Report dated Sep. 27, 2022 for the corresponding European Patent Application No. 20748990.7 (7 pages). |
| Number | Date | Country | |
|---|---|---|---|
| 20210323713 A1 | Oct 2021 | US |
