JP5468278B2 - Can lid - Google Patents

Description

  The present invention relates to a can lid used for a beverage can, and more particularly to a can lid used for a positive pressure can on which an internal pressure acts.

When filling effervescent beverages such as beer and carbonated beverages as contents, or when non-effervescent beverages such as tea and coffee are filled with liquid nitrogen during filling, so-called positive pressure is applied after sealing. The pressure can is required to have a strength that can withstand the internal pressure. For example, in order to increase the pressure resistance of the can lid, various proposals have been made such as reducing the width of the counter sink part or devising the shape of the chuck wall part.
The can lid described in Patent Document 1 has a shape in which the inclination angle of the chuck wall portion with respect to the vertical direction is increased, the diameter of the counter sink portion is reduced, and the width of the counter sink portion is reduced.
In addition, the can lid described in Patent Document 2 has the chuck wall portion formed into a continuous shape of a plurality of curved portions, and the corner portion between the counter sink portion and the panel portion inside the counter sink portion is greatly inclined, thereby The shape is reduced in diameter.

Japanese Patent No. 3809190 Special table 2007-526859 gazette

By the way, the cans filled with the contents are heat-treated for sterilization, and then transported to various places in a state where a plurality of cans are packed in cartons. Phenomenon occurs. When the tab of the can lid protrudes from the upper end of the can due to the bulging, the tab cannot be protected from external force, and is disposed as a defective product (so-called bulge failure). Even when such a bulge failure does not occur, when the carton is packed and transported for a long distance, there is a possibility that the tab may come into contact with the carton due to the vibration.
On the other hand, in order to reduce material costs, it is also required to reduce the plate thickness of the can lid. For this reason, further improvement in pressure resistance is required.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a can lid capable of improving pressure resistance and preventing occurrence of a bulge failure or leakage during transportation.

The can lid of the present invention is a can lid having a nominal diameter of 204, and the ratio of the outer diameter of the panel portion to the outermost diameter of the tightened portion after the can lid is wound around the can body is 70.7% or more. 83.0% or less, and a counter sink part that forms an annular recess facing upward is continuously formed on the outer peripheral edge of the panel part to which the tab is attached, and upward from the outer peripheral edge of the counter sink part. A chuck wall portion that gradually increases in diameter as it goes is formed, and a curled portion formed by folding the outer peripheral edge downward and radially inward through a shoulder portion that extends radially outward from the chuck wall portion is continuous. In the formed can lid, the radius of curvature of the inner bottom surface of the counter sink portion is 0.75 mm or less, and the vertical dimension from the apex of the portion from the shoulder portion to the curl portion to the surface of the panel portion is set. The ratio of the panel depth to the outer diameter of the panel portion when the depth of the panel is 10.17% or more and 11.03% or less, and the overall height of the can lid is 7.02 mm or less. .

In other words, the tab protrudes upward from the upper end of the can because the panel portion is displaced so as to be lifted upward. Therefore, by suppressing the displacement of the panel portion, a bulge failure or during transportation is suppressed. Leakage can be prevented. For this reason, in the can lid of the present invention, the radius of curvature of the inner bottom surface of the counter sink portion is reduced to 0.75 mm or less, and the deformation strength of the counter sink portion is increased, so that the panel portion starting from the counter sink portion is While suppressing the displacement, the ratio of the outer diameter of the panel part to the panel depth is 10.17 % or less and 11.03% or less. The tab did not protrude from the upper end of the can even if it bulged. In order to obtain the effect, 10.17% or more is necessary. If it exceeds 02 mm, troubles occur when supplying the can lid at the time of filling, and problems such as hindering an increase in the filling speed occur.

In the can lid of the present invention, the corner portion extending from the panel portion to the counter sink portion includes an inner bent portion adjacent to the panel portion and an outer bent portion adjacent to the inner wall portion of the counter sink portion. And an inclined portion that connects the two bent portions.
The outer peripheral edge of the panel portion is separated from the counter sink portion by the amount of the inclined portion at the corner portion. Accordingly, the outer diameter of the panel portion can be reduced without changing the shape and dimensions of the counter sink portion and the outer chuck wall portion, and the swelling of the panel portion can be further suppressed.

  According to the can lid of the present invention, by reducing the curvature radius of the counter sink portion and increasing the deformation strength of the counter sink portion, the displacement of the panel portion starting from the counter sink portion is suppressed, and the panel portion The panel has a relatively large depth with respect to the outer diameter, and the tab is difficult to protrude from the upper end of the can, so that the pressure resistance can be improved and the occurrence of bulge failure and leakage during transportation can be prevented.

It is a longitudinal cross-sectional view of the principal part of the can lid in embodiment of this invention. It is a longitudinal cross-sectional view which shows the state which wound the can lid in FIG. 1 around the can body. It is a model figure which shows the loading state of the carton at the time of implementing the vibration leak test of a can lid.

Hereinafter, an embodiment of a can lid according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the can lid 1 of this embodiment is a panel part 2 having a disc shape disposed in the center part thereof, and continuous from the outer peripheral edge of the panel part 2 via the corner part 3. A counter sink portion 5 that forms an annular recess 4 facing downward, a chuck wall portion 6 that extends from the outer peripheral edge of the counter sink portion 5 while increasing in diameter upward, and an outer peripheral edge of the chuck wall portion 6. And a curled portion 8 continuing from the shoulder portion 7.

  The panel part 2 is formed in a disk shape as a whole, a tab is attached to the center thereof, and a score that is opened by raising this tab and becomes a drinking mouth on the upper surface, and a bead that reinforces the periphery of the score, By forming a recess or the like (both not shown) for forming a finger-hanging portion when raising the tab, some unevenness is formed.

  The corner portion 3 between the panel portion 2 and the counter sink portion 5 has an upward convex inner bent portion 11 connected to the outer peripheral edge of the panel portion 2 and an upward convex shape connected to the inner wall portion 12 of the counter sink portion 5. The outer bent portion 13 and the inclined portion 14 that connects the bent portions 11 and 13 are continuously formed.

In the counter sink part 5, the inner wall part 12 connected to the corner part 3 extends so as to slightly increase in diameter as it goes vertically downward. The curved portion 16 is continuous. The curved portions 15 and 16 are formed so that the inner curved portion 15 protrudes downward and radially inward so that the bottom of the counter sink portion 5 is formed in half, and the outer curved portion 16 And it is set as the shape which becomes convex toward radial outward. The outer wall portion 17 extends from the outer curved portion 16 while slightly expanding the diameter upward. The inner wall portion 12, the inner curved portion 15, the outer curved portion 16, and the outer wall portion 17 form a substantially U-shape. A counter sink portion 5 having a cross section is formed.
In this case, the curvature radii R1 and R2 of the inner peripheral surfaces of the inner curved portion 15 and the outer curved portion 16 are formed to have substantially the same dimensions. In addition, since the inner wall portion 12 and the outer wall portion 17 are inclined so as to gradually approach as they go downward, the width of the annular recess 4 gradually decreases as it goes downward.

The chuck wall portion 6 is continuous with the upper edge of the outer wall portion 17 of the counter sink portion 5 and is continuous with the upper edge of the first curved portion 18 and the first curved portion 18 that is curved so as to protrude inward. The second curved portion 19 is curved so as to be convex toward the outside. The continuous shape of the first curved portion 18 and the second curved portion 19 expands upward as a whole. The shape is a diameter.
The shoulder portion 7 is continuous with the upper end edge (outer peripheral edge) of the second curved portion 19 of the chuck wall portion 6 and extends radially outward while being curved so as to be convex upward. In this case, since the second curved portion 19 of the chuck wall portion 6 is curved so that the inner surface thereof is inclined obliquely upward, the overall shape is gradually increased from the bottom toward the top. In addition, the shoulder portion 7 continuing to the second curved portion 19 is also enlarged in diameter from the bottom to the top.
The curled portion 8 extends radially outward continuously from the outer peripheral edge of the shoulder portion 7, and has a shape formed by folding the outer peripheral edge downward and radially inward.

On the other hand, the can body 21 around which the can lid 1 is wound is provided with an outward flange portion 24 via a bent portion 23 at the upper end of a neck portion 22 whose diameter is reduced from a bottomed cylindrical body portion (not shown). The shape is formed continuously.
When the can lid 1 is put on the can body 21, the outer surface of the shoulder portion 7 of the can lid 1 is disposed so as to face the bent portion 23 of the can body 21, and the shoulder portion 7 is disposed on the upper surface of the flange portion 24. To the curled portion 8 are arranged opposite to each other. In this state, when the curled portion 8 of the can lid 1 is wound along the circumferential direction while being integrally wound with the flange portion 24 of the can body 21, the curled portion 8 is folded back into the rolled portion. A double winding fastening portion 25 is formed in which the flange portion 24 is inserted and the can lid 1 and the can body 21 sandwich each other.

  In the can lid 1 configured as described above, the nominal diameter is 204 (the outermost diameter D2 of the tightening portion 25 after the can lid 1 is wound around the can body 21 is 56.5 to 56.7 mm, before the tightening. The outer diameter D1 of the panel portion 2 is 40.0 to 48.69 mm, and the panel depth P is 4 in the case where the outermost diameter of the curled portion 8 of the can lid 1 is 62.0 to 62.4 mm). .25 to 5.05 mm. The panel depth P refers to the vertical dimension from the apex of the portion from the shoulder portion 7 to the curled portion 8 before the can lid 1 is wound around the can body 21 to the surface of the panel portion 2. Further, the radii of curvature R1 and R2 of the inner surfaces of the curved portions 15 and 16 forming the inner bottom surface of the counter sink portion 5 are both 0.15 to 0.75 mm. Within this range, both the curved portions 15 and 16 may have the same curvature radius or different curvature radii.

When the nominal diameter is 202 (the outermost diameter D2 of the tightening portion 25 is 53.6 to 54.4 mm, and the outermost diameter of the curled portion 8 of the can lid 1 before tightening is 59.2 to 59.6 mm) The outer diameter D1 of the panel portion 2 is 38.0 to 46.36 mm, and the panel depth P is 3.8 to 4.79 mm. The curvature radii R1 and R2 of the inner surfaces of both curved portions 15 and 16 of the counter sink portion 5 are both 0.15 to 0.75 mm as in the case of 204.
The nominal diameter is 206 (the outermost diameter D2 of the tightened portion 25 after being tightened is 59.2 to 59.4 mm, and the outermost diameter of the curled portion 8 of the can lid 1 before being tightened is 64.5 to 64. 9mm), the outer diameter D1 of the panel portion 2 is 42.0 to 48.9 mm, and the panel depth P is 4.3 to 5.05 mm. The curvature radii R1 and R2 of the inner bottom surfaces of both curved portions 15 and 16 of the counter sink portion 5 are both 0.15 to 0.75 mm.

  In either case, the panel portion 2 slightly swells as indicated by the chain line in FIG. 1 due to the internal pressure, but in order to prevent the tab from protruding from the upper end surface of the can due to the bulging deformation, the panel portion 2 The ratio of the panel depth P to the outer diameter D2 (P / D1) is an important factor and is preferably 10.17% or more. If the ratio is less than 10.17%, when the panel portion 2 bulges due to the internal pressure, a part of the tab tends to protrude from the upper end of the can, while the ratio (P / D1) becomes too large. When the overall height h of the lid 1 exceeds 7.2 mm, the height of the pass line when the can lid 1 is supplied to the can body 21 in the winding machine needs to be adjusted and supplied. Inconveniences such as the occurrence of jam sometimes occur easily, and the stroke until the can lid 1 sent above the can body 21 is placed on the flange portion 24 of the can body 21 becomes large, and accordingly, high speed filling is performed. May interfere. Therefore, the overall height h of the can lid 1 is preferably within 7.2 mm.

Next, with respect to the can lid 1 configured as described above, various samples with different dimensions such as the outer diameter D2 and the panel depth P of the panel portion 2 were prepared, and a vibration leakage test, a pressure resistance test, and the like were performed. .
The can lids and cans used had three nominal diameters of 204, 202, and 206. The plate thickness T of the can lid was 0.215 to 0.230 mm in the case of 204, 0.215 to 0.230 mm in the case of 202, and 0.215 to 0.250 mm in the case of 206. Since the radius of curvature of the inner bottom surface of the counter sink portion 5 is the same radius of curvature for both the inner curved portion and the outer curved portion, they are unified as R in each table.
Table 1 shows the case where the nominal diameter 204, Table 2 are the nominal diameter 202, and Table 3 is the nominal diameter 206, respectively.

  In the vibration leak test, a three-way simultaneous vibration test apparatus manufactured by SHINKEN Co., Ltd. is used. As shown in FIG. 3, the can 31 filled with the contents is put in a 24 can carton 32, and a dummy can 33 is placed thereon. Two cases of the put carton 34 are placed, and a weight 35 is placed thereon. These cartons 32 and 34 are assembled so as to go around 24 cans arranged, and folding portions 32a and 34a are formed only at one place in the turning direction. And the folding parts 32a and 34a of each carton 32 and 34 are arrange | positioned in the state match | combined in the same direction. The weight 35 is 51 kg, the frequency is 10 Hz, the amplitude is 5 mm, the vibration direction is only in the vertical direction, the occurrence of leakage is confirmed every 5 minutes, and the evaluation is based on the time at which any can 31 in the carton 32 has leaked. did. Products that have not leaked for more than 30 minutes are considered good. Reference numeral 36 in FIG. 3 denotes a guide disposed around the cartons 32 and 34.

In the pressure test, the can lid is wrapped around an empty can body, the can body is cut at the middle part, and then a pressure test apparatus manufactured by Floris Enterprise Co., Ltd. is used, and the water pressure is increased at a pressure increase rate of 100 kPa / 30 seconds. Then, the pressure at the time when buckling phenomenon or score cracking, in which a part of the can lid partially protrudes, occurred, was measured. A product with no buckling or score cracking up to 570 kPa is regarded as a good product.
Comprehensive judgment is a good product in these vibration leakage test and pressure resistance test, and the overall height of the can lid is within 7.2 mm, ○, and one that does not meet any of these criteria is × did.

  As can be seen from these results, in the can lid in which the ratio of the panel depth P to the outer diameter D1 of the panel portion 2 (P / D1) is 10.17% or more, the standard of 30 minutes or more even in the vibration leakage test. In addition, it exhibits good pressure resistance in the pressure resistance test, and if the overall height of the can lid is suppressed to 7.2 mm or less, troubles during filling and a reduction in filling speed may result. It is not.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, in the embodiment, the chuck wall portion of the can lid is configured by a continuous shape of two curved portions, but may be configured by one curved portion, a substantially straight tapered surface, or the like. In addition, the corner portion between the panel portion and the counter sink portion has a shape in which an inclined portion is formed between the two bent portions, but one radius of curvature is provided between the panel portion and the inner wall portion of the counter sink portion. It is good also as a shape made to continue in the bent part.

DESCRIPTION OF SYMBOLS 1 Can lid 2 Panel part 3 Corner part 4 Annular recessed part 5 Counter sink part 6 Chuck wall part 7 Shoulder part 8 Curl part 11 Inner bending part 12 Inner side wall part 13 Outer bending part 14 Inclination part 15 Inner bending part 16 Outer bending part 17 Outer wall portion 18 First bending portion 19 Second bending portion 21 Can body 22 Neck portion 23 Bending portion 24 Flange portion

Claims (2)

The nominal diameter of the can lid is 204, and the ratio of the outer diameter of the panel portion to the outermost diameter of the tightened portion after the can lid is wound around the can body is 70.7% or more and 83.0% or less. A counter sink part that forms an upward annular recess is formed continuously on the outer peripheral edge of the panel part to which the tab is attached, and the diameter gradually increases from the outer peripheral edge of the counter sink part upward. In the can lid in which a chuck wall portion is formed, and a curled portion is formed by continuously folding the outer peripheral edge portion downward and radially inward through a shoulder portion extending radially outward from the chuck wall portion, The radius of curvature of the inner bottom surface of the counter sink part is 0.75 mm or less, and the vertical dimension from the apex of the part from the shoulder part to the curl part to the panel part surface is defined as the panel depth. Kino can lid the ratio of the panel depth to an outer diameter of less 11.03% or more 10.17% and total height of the can lid of the panel portion is equal to or less than 7.02mm.   The corner portion extending from the panel portion to the counter sink portion has an inner bent portion adjacent to the panel portion, an outer bent portion adjacent to the inner wall portion of the counter sink portion, and a space between both bent portions. The can lid according to claim 1, wherein the can lid is composed of connecting inclined portions.

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