JP6158897B2 - Can lid winding method - Google Patents

Description

  The present invention relates to a method for tightening a can lid that is attached to the open end of a can body by double winding the can lid.

  As shown in FIG. 6, the double winding of the can lid (55) with respect to the opening end of the can body (50) is performed by seaming extending to the outer peripheral edge of the chuck wall (56) of the can lid (55). The panel (57) is wound around the outside of the flange (51) of the can body (50) and crimped from the outside so that the can body (50) and the can lid (55) are brought into close contact with each other. In such double winding, in order to reduce the cost, the length of the seaming panel (57) is reduced to reduce the winding width (W) of the winding portion (58) formed by winding. The mini-seam (W = about 2.4 mm) is widely adopted overseas. In FIG. 6, the left diagram shows a state during winding tightening, and the right diagram shows a state when winding tightening is completed.

  However, since the reduction of the can lid material is limited only by reducing the winding width (W), a can lid having an improved chuck wall shape using a mini seam has been proposed (Patent Documents 1 and 2). reference).

  The can lid described in Patent Document 1 has a chuck wall inclined angle of 20 ° to 60 °, which was conventionally about 10 °, and reduces the diameter of a disc punched with a material. be able to. Further, the can lid described in Patent Document 2 is a two-stage chuck formed such that the chuck wall is bent at an intermediate portion in the height direction, and the inclination angle of the upper portion is smaller than that of the lower portion so as to be steeply inclined. It is a can lid of the wall. When this can lid is wound around a chuck wall with a large inclination angle, the upper part is bent and the diameter is reduced, and the holding of the can lid by the chuck becomes unstable and chuck slip occurs, resulting in poor tightening. This is an improvement of the problem of the can lid of Patent Document 1 that it is easy to do. If the upper part of the chuck wall is formed with a steep slope, the diameter reduction process at the time of winding can be omitted or the amount of diameter reduction can be reduced. Generation can be reduced.

  As for conventional can lids having a small inclination angle of the chuck wall, in order to improve the poor tightening, those defining the shape of the seaming panel have been proposed (see Patent Documents 3 and 4).

  The can lid described in Patent Document 3 defines the radius of curvature of the seaming panel and the angle of the tip. In the can lid described in Patent Document 4, a cover hook on the tip side of the seaming panel is formed by curved portions having two stages of curvature radii R1 and R2, and the magnitude relationship between R1 and R2 is defined.

Japanese National Patent Publication No. 11-505791 JP 2002-178072 A Japanese Patent No. 2642110 Japanese Patent No. 3714160

  However, even in the can lid of the two-stage chuck wall described in Patent Document 2, since the inclination angle of the lower portion is large, when the internal pressure is applied, a force toward the center of the can is greatly exerted by this action at the tightening portion. There is a problem in that the sealing force is lowered due to the force acting in the direction in which the winding part opens.

  References 3 and 4 describe that the shape of the seaming panel is defined in a can lid having a small inclination angle of the chuck wall. In a chuck wall having a small inclination angle, since the movement of the chuck wall in the can axis direction and the can diameter direction is small during winding, the shape of the seaming panel may be a relatively simple shape proposed in these documents. In addition, the seam panel of the mini seam type that adopts these shapes can make the entire seam relatively short, so the shape of the seam panel may be simple, and the arc shape has a flange (51 ) Is enough if you don't get along. However, in the case of a chuck wall can lid having a large inclination angle, the seam panel is moved in the can axis direction and the can diameter direction together with the winding because the bending process is performed while the coil wall is tightened. For this reason, even if the simple shape seaming panel described in Documents 3 and 4 is applied, such complicated movement cannot be sufficiently followed, and there is a risk that a chuck error or a winding failure may occur. .

  In view of the technical background described above, the method for winding a can lid of the present invention reduces chuck mistakes and winding failures during winding in a can lid having a large inclination angle of the chuck wall, and consequently the sealing performance of the winding portion. The purpose is to improve.

  That is, the method for winding a can lid of the present invention has the configurations described in [1] to [7] below.

[1] An annular groove that is recessed toward the inside of the can is formed on the outer peripheral edge of the center panel, a chuck wall that rises outwardly from the outer peripheral edge of the annular groove is extended, and further, a seat wall is formed from the outer peripheral edge of the chuck wall. The can lid with the extending panel is
A portion of the chuck wall on the annular groove side is formed with an inclination angle of 40 to 60 ° with respect to the can axis direction,
When the seaming panel is outward from the chuck wall side, a seaming panel radius portion having an outer radius of curvature (R1), a first seaming wall portion having an outer radius of curvature (R2), and an outer radius of curvature (R3). 2 seaming wall portions, cover hook portions having an outer radius of curvature (R4) are sequentially connected, and the tips of the cover hook portions are directed toward the center of the can lid, and the radius of curvature of each portion is R2>R1> R4 and While satisfying the relationship of R2 ≧ R3> R4, the distance (X) in the can radial direction from the maximum outer periphery of the can lid to the tip of the cover hook portion is formed to be 0.2 to 3.0 mm,
The can lid is tightened by winding the seam panel of the can lid on the opening end of the can body to form a tightening portion having a tightening width (W) of 2.6 to 2.9 mm. .

  [2] The method of winding a can lid according to the preceding item 1, wherein the chuck wall of the can lid is formed at an inclination angle (θ) of 40 to 60 ° as a whole.

  [3] The chuck wall of the can lid is bent at an intermediate portion in the can axis direction, and an inclination angle (θ1) of the first chuck wall portion on the annular groove side with respect to the can axis direction is formed to be 40 to 60 °, The can lid winding method according to the preceding item 1, wherein an inclination angle (θ2) of the second chuck wall portion on the seaming panel side with respect to the can axis direction is 1 to 39 °.

  [4] The seaming panel of the can lid has an outer surface curvature radius (R1) of the seaming panel radius portion of 1.3 to 2.3 mm, and an outer surface curvature radius (R2) of the first seaming wall portion. 2.0 to 7.0 mm, the outer surface curvature radius (R3) of the second seaming wall portion is 1.0 to 2.3 mm, and the outer surface curvature radius (R4) of the cover hook portion is 0.3. 4. The method for winding a can lid according to any one of the preceding items 1 to 3, which is ˜1.3 mm.

  [5] The seaming panel of the can lid has a distance (h) in a can axis direction from an uppermost end of the seaming panel to a lower end of the cover hook portion of 2.2 to 2.5 mm, and the seaming panel The can lid winding method according to any one of the preceding items 1 to 4, wherein a distance (L) in a can radial direction from an uppermost end of the cover to a maximum outer periphery of the cover hook portion is 1.9 to 2.3 mm.

[6] The flange of the can body and the seaming panel of the can lid are arranged between the first-stage winding roll and the chuck, the winding roll and the chuck are brought close to each other, and the seaming panel is placed in the groove of the winding roll. The boundary portion between the seaming panel radius portion and the first seaming wall portion and the vicinity thereof are bent while pushing in, and the portion of the second seaming wall portion on the cover hook portion side and the second seaming wall of the cover hook portion are also bent. Bend the side part to engage the flange,
6. The head according to any one of the preceding items 1 to 5, wherein the second stage winding roll and chuck in which the inner wall of the groove is formed substantially perpendicularly further presses the tightening portion by the first stage winding roll and tightens strongly. How to tighten the can lid.

  [7] The method for winding a can lid according to item 6 above, wherein the seaming panel is brought into contact with a lower shoulder of the groove of the first-stage winding roll.

  According to the invention described in [1], at least the annular groove side portion of the chuck wall is formed at an inclination angle of 40 to 60 °, thereby reducing the blank diameter of the can lid material and saving material. By defining the shape of the seaming panel, it is possible to reduce chucking errors and winding failures, and to improve the sealing and pressure resistance of the can lid.

  According to the invention described in [2], the above effect can be obtained in the can lid in which the entire chuck wall is formed at an inclination angle of 40 to 60 °.

  According to the invention described in [3], the above effect can be obtained in the can lid of the two-stage chuck wall. Moreover, since the inclination angle of the second chuck wall portion is smaller than that of the first chuck wall portion, the movement in the can diameter direction at the time of winding is reduced, and the winding failure is less likely to occur.

  According to each invention described in [4] and [5], it is possible to further reduce winding defects.

  [6] According to the invention described in [7], it is possible to reduce winding defects.

It is sectional drawing and partial expanded sectional view which show 1st Embodiment of the can lid used for the winding method of this invention. It is an expanded sectional view of a seaming panel. It is sectional drawing which shows the winding process of the can lid of FIG. It is an expanded sectional view of a winding part. It is sectional drawing which shows 2nd Embodiment of the can lid used for the winding method of this invention, and a partial expanded sectional view. It is sectional drawing which shows the conventional can lid and the winding process.

[First Embodiment]
1 and 2 show a first embodiment of a can lid used in the can lid winding method of the present invention. This can lid (1) is a can lid used for beverage cans, which is a blank formed by punching a metal plate such as aluminum into a circular shape, and before being attached to the open end of the can body Indicates the state.

  In the can lid (1), an annular groove (11) is formed in the periphery of the circular center panel (10), which is recessed on the inner side of the can (lower side in the drawing). A chuck wall (15) is formed outside the annular groove (11). ) And a seaming panel (20) that is wound around the open end of the can body.

  The annular groove (11) has an inner wall (12) extending from the outer peripheral edge of the center panel (10) to the inside of the can and an outer wall (13) facing the inner wall (12) at their lower ends. It is connected via an arcuate bottom wall (14).

  The chuck wall (15) extends from the upper end of the outer wall (13) via an arc-shaped bent portion (16), and rises obliquely outward. The chuck wall (15) is a one-stage chuck wall formed as a whole in an angle of inclination (θ) with respect to the can axis direction of 40 to 60 °.

  The seaming panel (20) includes a seaming panel radius portion (21), a first seaming wall portion (22), a second shape formed in an arc shape from the chuck wall (15) side outward. The seaming wall portion (23) and the cover hook portion (24) are sequentially connected, and these cover hook portions are formed by forming the outer surface curvature radii (R1), (R2), (R3), and (R4) into an arc shape. The tip of (24) faces the center direction of the can lid (1).

  Hereinafter, the process of attaching the can lid (1) to the open end of the can body (50) will be described with reference to FIGS. 3 (A), (B), and (C).

  [I] Between the first-stage winding roll (40) and the chuck (41), the can lid (1) and the can body (50) are connected, and the flange (51) of the can body (50) is the seaming panel ( The seaming panel radius part (21) and the first seaming wall part (22) of 20) are arranged so as to be covered (see FIG. 3A).

  [Ii] As shown in FIG. 3A, the winding roll (40) and the chuck (41) are brought close to each other and the seaming panel (20) is pushed into the groove (42) of the winding roll (40). The boundary portion of the seaming panel radius portion (21) and the first seaming wall portion (22) and the vicinity thereof are bent, and the portion of the second seaming wall portion (23) on the cover hook portion (24) side and The second seaming wall side portion of the cover hook portion (24) is bent so as to engage with the flange (51). As a result, as shown in FIG. 3B, the cover hook portion (24) is fed between the can body (50) and the flange (51) without hitting the can body (50).

  [Iii] As shown in FIG. 3 (C), the tightening portion is further pressed by the second-stage winding roll (43) and the chuck (41) in which the inner wall of the groove is formed almost vertically, and the winding is strongly wound. Tighten. As a result, as shown in FIG. 4, the chuck wall (15) side portion of the seaming panel radius portion (21), the second seaming wall (23) side portion of the first seaming wall (22), the second portion The first seaming wall (22) side portion of the seaming wall (23) and the tip end portion of the cover hook portion (24) are processed to be substantially flat, and the tightening portion (25) having a tightening width (W) is formed. It is formed.

[Second Embodiment]
The can lid (2) of the present embodiment shown in FIG. 5 differs from the can lid (1) of the first embodiment described above only in the shape of the chuck wall, and the other portions have the same configuration. For this reason, description and illustration are abbreviate | omitted as the part which attached | subjected the same code | symbol as the can lid (1) of 1st Embodiment represents the same part.

  In the can lid (2), the chuck wall (30) is bent at an intermediate portion in the can axis direction, and the first chuck wall portion (31) on the annular groove (11) side and the above-mentioned via the bent portion (33). This is a two-stage chuck wall formed at a different inclination angle from the second chuck wall portion (32) on the seaming panel (20) side. The first chuck wall portion (31) has an inclination angle (θ1) with respect to the can axis direction of 40 to 60 °, and the second chuck wall portion (32) is inclined more than the first chuck wall portion (31) ( θ2) is small and is formed at 1 to 39 °.

  In addition, the seaming panel (20) is the same as the can lid (1), the seaming panel radius portion (21) having the outer radius of curvature (R1) and the first seaming wall portion (22) having the outer radius of curvature (R2). ), A second seaming wall portion (23) having an outer surface curvature radius (R3) and a cover hook portion (24) having an outer surface curvature radius (R4) are sequentially connected. Further, the can lid (2) of the present embodiment is attached to the open end of the can body (50) in the same manner as the can lid (1).

  In the can lid (2) of the two-stage chuck wall, the inclination angle (θ2) of the second chuck wall portion (32) is smaller than the inclination angle (θ1) of the first chuck wall portion (31). The movement in the can diameter direction is small. For this reason, it is hard to generate the winding defect at the time of winding more than the can lid (1) of 1st Embodiment which inclined the whole chuck wall to 40-60 degrees.

  The shape of each part in the can lid of the present invention and the reason for its definition will be described in detail.

  In the can lids (1) and (2), an annular groove (11) is formed on the outer peripheral edge of the center panel (10). The shape of the annular groove (11) is not limited at all. In the illustrated annular groove (11), the height and inclination angle of the inner wall (12) and the outer wall (13), the radius of curvature of the bottom wall (14), the groove width, etc. are not limited at all. However, the inner wall radius of curvature of the bottom wall (14) is preferably 0.75 mm or less in order to increase the pressure resistance. The tip of the chuck enters the annular groove (11) at the time of winding, but as the inner surface radius of curvature decreases, the bending rate at the time of press molding of the can lid increases and the ductility decreases, and brittle fracture is more likely at the time of winding. . For this reason, it is preferable to form the said internal surface curvature radius in 0.4-0.6 mm. Further, the inner wall (12) and the outer wall (13) are preferably opened parallel to the can axis or at an inclination angle of 15 ° or less with respect to the can axis from the viewpoint of improving the strength.

  The chuck walls (15) and (30) are required to have an inclination angle (θ) (θ1) with respect to the can axis direction of at least 40 to 60 ° at least on the annular groove (11) side. When the inclination angle (θ) (θ1) is 60 ° or more, the processing rate of the bent portion (16), which is the connecting portion with the outer wall (13), increases, and processing embrittlement is likely to occur. When the bent portion (16) becomes brittle due to processing, cracking occurs when a buckling or the like due to an increase in internal pressure occurs, and protrusion is likely to occur. On the other hand, when the inclination angle (θ) (θ1) is less than 40 °, the cost reduction effect due to the material reduction is small. A particularly preferable inclination angle (θ) (θ1) is 45 to 55 °.

  The chuck wall (15) (30) may be a chuck wall (15) as a whole inclined at the inclination angle (θ) as shown in FIG. 1, or the inclination angle changes at an intermediate portion as shown in FIG. The two-stage chuck wall may be formed so that the inclination angle (θ1) of the first chuck wall portion (31) on the annular groove (11) side is 40 to 60 °. In the two-stage chuck wall, the inclination angle (θ2) of the second chuck wall portion (32) on the seaming panel (20) side is reduced in order to reduce the movement in the can axis direction and the can diameter direction during winding. It is preferable to make it smaller than the inclination angle (θ) of the first chuck wall portion (31), and preferably 1 to 39 °. A particularly preferable inclination angle (θ2) of the second chuck wall portion (32) is 20 to 30 °.

  The seaming panel (20) has a seaming panel radius portion (21), a first seaming wall portion (22), a second seaming wall portion (23), from the chuck wall (15) side outward. It is divided into four parts of the cover hook part (24), and the outer surface curvature radii (R1), (R2), (R3), and (R4) must satisfy the following (formula 1) and (formula 2).

(Formula 1): R2>R1> R4
(Formula 2): R2 ≧ R3> R4
Since the seam panel radius portion (21) and the first seaming wall portion (22) are portions where the flange (51) of the can body (50) is disposed inside the seam panel radius portion (21) and the first seaming wall portion (22). (R1) (R2) is preferably close to the curvature of the flange (51), and excessively small is not preferable. The seaming panel radius portion (21) is finally wound around the flange (51) of the can body (50) from the outside, and the first seaming wall portion (22) is finally flat on the winding portion (25). Therefore, the outer surface curvature radius (R2) of the first seaming wall portion (22) is preferably larger than the outer surface curvature radius (R1) of the seaming panel radius portion (21). Therefore, R2> R1.

  Since the first seaming wall portion (22) and the second seaming wall portion (23) are portions that finally become the flat outer surface of the tightening portion (25), they are connected by a continuous arc, The outer surface curvature radius (R2) (R3) can be set to R2 = R3. However, on the other hand, the second seaming wall portion (23) is connected to the cover hook portion (24) that forms the outer radius of curvature (R4) to be engaged with the flange (51). It is also preferable to make the outer surface curvature radius (R3) of the wall portion (23) smaller than that of the first seaming wall portion (R2). Therefore, R2 ≧ R3.

  The cover hook portion (24) is a curved portion for winding the tip of the flange (51), and needs to be bent slightly in order to be wound inside the winding fastening portion (25). For this reason, it sets to the outer surface curvature radius (R4) smaller than the seaming panel radius part (21) wound from the outer side. Therefore, R1> R4. The second seaming wall part (23) is a continuous part of the cover hook part (24) wound inside the flange (51), but follows the cover hook part (24) because it is not the starting end of the winding. Although a curvature as small as possible is necessary, it is not necessary to set it as small as (R4). Therefore, R3> R4.

  When the above conditions are combined, it is necessary to satisfy the above (Formula 1) and (Formula 2).

  Also, after setting the outer surface curvature radius of each part of the seaming panel (20) so as to satisfy the above-described conditions, the can hook diameter direction of each part so that the tip of the cover hook part (24) faces the center direction of the can lid The distance (X) in the can radial direction from the maximum outer periphery of the can lids (1) and (2) to the tip of the cover hook portion (24) is formed to be 0.2 to 3.0 mm. When the distance (X) is less than 0.2 mm, it is difficult to wind the flange (51) at the time of winding, which tends to cause a winding failure. On the other hand, if it exceeds 3.0 mm, it may hit the peripheral surface of the can body (50) and be damaged. A preferable range of the distance (X) is 0.6 to 1.1 mm.

  It is preferable that the outer surface curvature radii (R1), (R2), (R3), and (R4) of the respective parts of the seaming panel (20) are set in the following ranges after defining the magnitude relationship.

  The outer surface radius of curvature (R1) of the seaming panel radius portion (21) is preferably in the range of 1.3 to 2.3 mm. The seaming panel radius portion (21) has an end portion (the end portion on the first seaming wall side) close to the highest position in the can axis direction so that the adjacent first seaming wall portion (22) is slanted. It is preferable to face downward, and the gap with the flange (51) is preferably minimized. If the outer radius of curvature (R1) is less than 1.3 mm, the gap between the flange (51) and the flange may become poor when tightening. If it exceeds 2.3 mm, the winding in the curling groove may occur. Tightening may be incomplete. By setting the outer radius of curvature (R1) within the above range, good winding can be reliably performed. A particularly preferable range of the outer radius of curvature (R1) is 1.6 to 2.0 mm.

  Since the first seaming wall portion (22) is a flat outer surface after winding, the outer surface curvature radius (R2) is preferably not too small, and is set in the range of 2.0 to 7.0 mm. It is preferable. If it is less than 2.0 mm, it is difficult to be flat when tightened, and if it exceeds 7.0 mm, the portion following the seaming panel radius portion (21) is difficult to wind. A particularly preferable outer surface curvature radius (R2) is 2.5 to 3.5 mm.

  The second seaming wall portion (23) becomes flat after winding, but it is preferable to smoothly connect the cover hook portion (24) having a small outer radius of curvature at the end portion (end portion on the cover hook portion). From such a viewpoint, it is preferable that the outer radius of curvature (R3) of the second seaming wall portion (23) is set in a range of 1.0 to 2.3 mm, particularly in a range of 1.2 to 1.7 mm. preferable.

  As the outer surface curvature radius (R4) is smaller, the cover hook portion (24) can be fed into the tip of the can body (50) without being hit against the can body (50), and the cover hook after being tightened is stabilized. However, if it is too small, the amount of winding will be insufficient, and when stacked, the stacking property between the lids may be deteriorated. On the other hand, if the outer radius of curvature (R4) becomes too large, it will easily hit the can body (50). From such a viewpoint, the outer surface curvature radius (R4) of the cover hook portion (24) is preferably set in the range of 0.3 to 1.3 mm, and particularly preferably in the range of 0.6 to 1.0 mm.

  Further, in the seaming panel (20), the distance (h) in the can axis direction from the uppermost end of the seaming panel (20) to the lower end of the cover hook portion (24) is 2.2 to 2.5 mm, and The distance (L) in the can diameter direction from the uppermost end of the seaming panel (20) to the maximum outer periphery of the cover hook portion (24) is preferably 1.9 to 2.3 mm. The distance (h) is governed by the combination of the outer surface curvature radii (R2), (R3), and (R4), the distance (X), and the angle of the cover hook portion (24), but the distance (h) is 2.5 mm. If the thickness is over, it will be difficult to wind the winding roll (40) during winding, and if it is less than 2.2 mm, the tab will easily come into contact with the panel, resulting in poor stacking properties such as scratching. A particularly preferable range of the distance (h) is 2.3 to 2.4 mm. The distance (L) is related to the weight of the tightening portion and is mainly governed by the distance (X). And in the can lid of the present invention in which the distance (X) is defined in the range of 0.2 to 3.0 mm, by setting the distance (L) in the range of 1.9 to 2.3 mm, high sealing is achieved. In order to obtain the properties, the optimum winding width can be obtained. A particularly preferable range of the distance (L) is 2.1 to 2.3 mm. As a result, it is preferable from the sealing property that the winding width (W) is within a midi seam of about 2.6 to 2.9 mm.

  As described above, according to the can lid winding method of the present invention, the chuck wall is formed at an inclination angle of 40 to 60 °, thereby reducing the blank diameter of the can lid material and saving the material. By defining the shape of the seaming panel, it is possible to reduce chucking mistakes and winding failures during winding and improve the sealing and pressure resistance of the can lid.

  In addition, the can lid used for the winding method of the present invention is not limited to a perfect circle, and includes can lids such as an oval shape and an oval shape. Further, as the can lid material, aluminum, an alloy thereof, or a metal such as steel is used.

  A can lid shown in Table 1 was manufactured using a plate material made of JIS A5182 and having a thickness of 0.24 mm.

  The can lid of Example 1 and Comparative Example 1 is a can lid (1) in which the entire chuck wall (15) referred to in FIG. 1 is formed at an inclination angle (θ) shown in Table 1. The can lids of Examples 2 to 4 and Comparative Examples 2 and 3 are can lids (2) having a two-stage chuck wall (30) referred to in FIG. 5, and the inclination angle of the first chuck wall portion (31). (Θ1) and the inclination angle (θ2) of the second chuck wall portion (32) are formed at the angles shown in Table 1. Further, in the seaming panel (20) of each can lid (1) (2), the outer surface radius of curvature (R1) of the seaming panel radius portion (21) and the outer surface radius of curvature of the first seaming wall portion (22) ( R2), the outer surface radius of curvature (R3) of the second seaming wall portion (23), the outer surface radius of curvature (R4) of the cover hook portion (24), and the cover hook portion from the maximum outer periphery of the can lid (1) (2) ( 24) Distance in the can radial direction to the tip (X), distance in the can axis direction from the top end of the seaming panel (20) to the bottom end of the cover hook (24), seaming panel (20) The distance (L) in the can diameter direction from the uppermost end to the maximum outer periphery of the cover hook portion (24) is numerically formed in Table 1. Further, regarding the outer surface curvature radius (R1) (R2) (R3) (R4) of each part of the seaming panel (20), (Expression 1): R2> R1> R4, (Expression 2): R2 ≧ R3> R4 What is satisfied is indicated by ○, and what is not satisfied is indicated by ×, and the distance (X) that is out of the scope of the present invention is underlined.

  Moreover, common to each can lid (1) (2), the maximum outer diameter of the can lid is 65 mm, the diameter of the center panel (10) is 47 mm, and the inner surface curvature of the bottom wall (14) constituting the annular groove (11) The radius is 0.5 mm, the inclination angle of the inner wall (12) is 5 °, and the inclination angle of the outer wall (13) is 2.7 °.

  Each can lid described above was double-wound onto the flange (51) of the can body (50) using winding rolls (40) (43) and a chuck (41), as shown in FIG. . At this time, the tightening width (W) of each tightening portion (25) was set to a numerical value in Table 1.

The can body in which the can lid (1) (2) was attached to the can body (50) was tested and evaluated for hermeticity and pressure resistance by the following methods. The evaluation results are also shown in Table 1.
〔sealability〕
A sealed can body was manufactured by filling carbon dioxide and water in a 350 ml beer can with a gas pressure of 245 kPa (2.5 kgf / cm ² ), immersed in hot water at 80 ° C. for 30 minutes, and the can lid swelled Those that did not come out were marked with x, and those that did not come off were marked with ○.
[Pressure resistance]
An internal pressure was applied to the inside of the can, and a case in which one protrusion (buckling) occurred in the bent portion (16) of the can lid at 539 kPa or less was evaluated as x, and a case in which no protrusion was generated at 539 kPa was marked as ◯.

  From the results shown in Table 1, it was confirmed that the can lids of each Example in which the shape of each part of the seaming panel was set within the scope of the present invention had excellent sealing properties and pressure resistance.

  The method for tightening the can lid of the present invention can be applied widely to containers for liquids such as beverages because excellent sealing and pressure resistance can be obtained at the tightening portion.

1, 2 ... Can lid
10 ... Center panel
11 ... annular groove
15, 30 ... Chuck wall
31 ... 1st chuck wall
32 ... Second chuck wall
20 ... Seaming panel
21 ... Seaming Panel Radius
22 ... 1st seaming wall
23 ... Second seaming wall
24 ... Cover hook part R1 ... Outer surface radius of curvature R2 of seaming panel radius part ... Outer surface radius of curvature R3 of first seaming wall part ... Outer surface radius of curvature R4 of second seaming wall ... Outer surface radius of curvature θ of cover hook part Inclination angle θ1 of the chuck wall ... Inclination angle θ1 of the first chuck wall part ... Inclination angle X of the second chuck wall part ... Distance h in the can diameter direction from the maximum outer periphery of the can lid to the tip of the cover hook part ... Seaming panel The distance L in the can axis direction from the uppermost end of the cover to the lower end of the cover hook portion. The distance in the can diameter direction from the uppermost end of the seaming panel to the maximum outer periphery of the cover hook portion.

Claims (5)

An annular groove recessed inside the can is formed on the outer peripheral edge of the center panel, a chuck wall rising obliquely outward from the outer peripheral edge of the annular groove is extended, and a seaming panel is further extended from the outer peripheral edge of the chuck wall. The extended can lid is
A portion of the chuck wall on the annular groove side is formed with an inclination angle of 40 to 60 ° with respect to the can axis direction,
When the seaming panel is outward from the chuck wall side, a seaming panel radius portion having an outer radius of curvature (R1), a first seaming wall portion having an outer radius of curvature (R2), and an outer radius of curvature (R3). 2 seaming wall portions, cover hook portions having an outer radius of curvature (R4) are sequentially connected, and the tips of the cover hook portions are directed toward the center of the can lid, and the radius of curvature of each portion is R2>R1> R4 and While satisfying the relationship of R2 ≧ R3> R4, the distance (X) in the can radial direction from the maximum outer periphery of the can lid to the tip of the cover hook portion is formed to be 0.2 to 3.0 mm,
Place the flange of the can body and the seaming panel of the can lid between the first stage winding roll and the chuck, bring the winding roll and chuck close together, and push the seaming panel into the groove of the winding roll The boundary portion between the seaming panel radius portion and the first seaming wall portion and the vicinity thereof are bent, and the cover hook portion side portion of the second seaming wall portion and the second seaming wall portion side portion of the cover hook portion When bending to engage with the flange, the seaming panel is brought into contact with the lower shoulder of the groove of the first-stage winding roll,
By further pressing the tightening portion by the first-stage winding roll and the second-stage winding roll and chuck in which the back wall of the groove is formed substantially vertically,
The can lid is tightened by winding the seam panel of the can lid on the opening end of the can body to form a tightening portion having a tightening width (W) of 2.6 to 2.9 mm. .   The can lid winding method according to claim 1, wherein the chuck wall of the can lid is formed at an inclination angle (θ) of 40 to 60 ° as a whole.   The chuck wall of the can lid is bent at an intermediate portion in the can axis direction, and an inclination angle (θ1) with respect to the can axis direction of the first chuck wall portion on the annular groove side is formed at 40 to 60 °, and the seaming The can lid winding method according to claim 1, wherein an inclination angle (θ2) of the second chuck wall portion on the panel side with respect to the can axis direction is 1 to 39 °.   The seam panel of the can lid has an outer surface curvature radius (R1) of a seaming panel radius portion of 1.3 to 2.3 mm, and an outer surface curvature radius (R2) of the first seaming wall portion of 2.0. To 7.0 mm, the outer surface curvature radius (R3) of the second seaming wall portion is 1.0 to 2.3 mm, and the outer surface curvature radius (R4) of the cover hook portion is 0.3 to 1.mm. It is 3 mm, The winding method of the can lid | cover in any one of Claims 1-3.   The can lid seaming panel has a distance (h) in the can axis direction from the uppermost end of the seaming panel to the lower end of the cover hook portion of 2.2 to 2.5 mm, and the uppermost end of the seaming panel The can lid winding method according to any one of claims 1 to 4, wherein a distance (L) in a can diameter direction from the maximum outer periphery of the cover hook portion to 1.9 to 2.3 mm.

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