CN115697851A

CN115697851A - Can lid

Info

Publication number: CN115697851A
Application number: CN202180038357.7A
Authority: CN
Inventors: 盐谷正博; 宫下理央
Original assignee: Daiwa Can Co Ltd
Current assignee: Daiwa Can Co Ltd
Priority date: 2020-05-28
Filing date: 2021-05-26
Publication date: 2023-02-03
Also published as: WO2021241639A1; JP2021187471A; TW202216545A; AU2021281838A1; EP4159636A1; US20230082001A1

Abstract

A can lid (1) is provided with: a score line (31) provided on the outer peripheral edge side of the disc-shaped panel portion (21); a rivet section (32) provided on the panel section (21) and adjacent to the inside in the radial direction of the score line (31); a tab (12) having a mounting portion (51) having a rivet hole (51 a) attached to the rivet portion (32), a distal end portion (52) continuous with the mounting portion (51), and a finger hook portion (53) formed on the opposite side of the distal end portion (52) across the mounting portion (51); and an auxiliary score line (33) which is formed on the panel portion (21) and has a first portion (41 a) which extends in an arc shape along the rivet portion (32) on the radially inner side of the panel portion (21) of the rivet portion (32), and a second portion which is continuous with the first portion, extends in a direction along a second straight line when a straight line passing through the center of the rivet portion and the tip of the tab is defined as the first straight line and a straight line passing through the center of the rivet portion and orthogonal to the first straight line is defined as the second straight line, and is positioned closer to the center side of the panel portion than the second straight line.

Description

Can lid

Technical Field

The present invention relates to a can lid for a can.

Background

Conventionally, as a can lid used for a can for food, a so-called full open type can lid having an open entire surface has been widely used. In a canned food for food, a can is filled with contents, and then a pressure and heat sterilization treatment is performed to form a final product, and the internal pressure of the can is a negative pressure. However, in recent years, as disclosed in japanese patent laid-open publication No. 2012-131518 and japanese patent laid-open publication No. 2-502814, a fully open type can cover has been proposed for use in a can having a positive internal pressure.

Such a can lid includes: an annular score line formed on the peripheral edge portion side of the panel portion and dividing the opening piece; and an auxiliary score line formed on the periphery of the rivet portion for mounting the opening tab. The auxiliary score line is broken by a second leverage using the tip of the tab as a fulcrum, the finger hook portion of the tab as a force point, and the rivet portion as an action point when the tab is lifted by hooking a finger to the finger hook portion of the tab at an initial stage of the opening operation of the tab.

By the rupture of the auxiliary score line, the panel portion around the rivet portion is easily deformed, and the lifting of the finger hook portion of the tab is facilitated. When the tab is further lifted from the state of the fracture of the auxiliary score line, the annular score line near the tip of the tab is fractured by a first lever action with the rivet as a fulcrum, the finger hook portion of the tab as a force point, and the tip of the tab as an action point. Then, as the finger hook portion of the tab is lifted upward, the annular score line is gradually broken in the circumferential direction, and the opening piece is removed from the can lid.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-131518

Patent document 2: japanese Kohyo publication Hei 2-502814

Disclosure of Invention

Problems to be solved by the invention

In the case of a can having a positive internal pressure, the central portion of the can lid bulges in a dome shape due to the internal pressure of the container, and therefore, the distal end portion of the tab is positioned on an inclined surface inclined downward toward the outer peripheral side.

Accordingly, an object of the present invention is to provide a can lid having sufficient opening performance even when used for a positive pressure can.

Means for solving the problems

According to one aspect of the present invention, a can lid includes: a disc-shaped panel portion; a score line provided on an outer peripheral side of the panel portion; a rivet portion provided on the panel portion and adjacent to an inner side in a radial direction of the score line; a tab having an attachment portion having a rivet hole attached to the rivet portion, a leading end portion continuous with the attachment portion, and a finger hook portion formed on an opposite side of the leading end portion with the attachment portion therebetween; and an auxiliary score line formed in the panel portion and having a first portion extending in an arc shape along the rivet portion radially inward of the rivet portion and a second portion continuous with the first portion, wherein when a straight line passing through a center of the rivet portion and a tip end of the tab is defined as a first straight line and a straight line passing through the center of the rivet portion and orthogonal to the first straight line is defined as a second straight line, the second portion extends in a direction along the second straight line and is positioned closer to a center side of the panel portion than the second straight line.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a can lid having sufficient opening performance even when used for a positive pressure can be provided.

Drawings

Fig. 1 is a plan view showing the structure of a can lid according to an embodiment of the present invention.

Fig. 2 is a sectional view showing the structure of the can lid.

Fig. 3 is a sectional view showing the structure of a main part of the can lid.

Fig. 4 is a sectional view showing the structure of a panel portion used for the can lid.

Fig. 5 is a sectional view showing a main part structure of a can using the can cover, and showing an example in which the can cover expands due to internal pressure.

Fig. 6 is a cross-sectional view showing an example of a state in which the ring is opened in the case where the can lid is expanded by the internal pressure.

Detailed Description

The structure of a can lid 1 having a tab 12 according to an embodiment of the present invention will be described below with reference to fig. 1 to 6.

Fig. 1 is a plan view showing the structure of a can lid 1 according to an embodiment of the present invention, and fig. 2 is a sectional view showing the structure of the can lid 1. Fig. 3 is a sectional view showing the structure of the periphery of the rivet portion 32 of the can lid 1, and fig. 4 is a sectional view showing the structure of the auxiliary score line 33 provided on the panel portion 21. Fig. 5 and 6 are cross-sectional views showing a structure of the can 100 using the can lid 1, in which the panel portion 21 of the can lid 1 bulges in a dome shape. Fig. 5 shows a structure before the opening operation by the tab 12, and fig. 6 shows a structure when the opening operation by the tab 12 is performed.

As shown in fig. 1, 2, 5, and 6, the can lid 1 is, for example, a so-called full open type in which the entire surface is opened. As shown in fig. 5 and 6, the can lid 1 is a member constituting, for example, an opening portion for discharging the contents of the can 100 containing, as contents, a retort pouch such as retort food, carbonated beverage, alcoholic beverage, or the like from the inside of the can 100 to the outside. The can lid 1 is integrally assembled to the can body 101 of the can 100 by seaming. Thereby, the can lid 1 and the can body 101 of the can 100 are hermetically fixed by the seaming portion 100 a.

The tank 100 is, for example, a positive pressure tank having a positive pressure inside. The can 100 may be a two-piece can or a three-piece can. The contents are not limited to food and drink, and may be contents other than food and drink. That is, various contents sealed in the can 100 can be used as the contents.

As shown in fig. 1 and 2, the can lid 1 includes a can lid body 11 and a tab (tab for can lid) 12. The can lid 1 is manufactured by press working a metal plate to mold the can lid body 11 and the tab 12 in different steps, and then fixing the tab 12 to the panel portion 21. Examples of the metal plate for forming the can lid body 11 include an aluminum alloy plate having a resin film formed on the surface thereof, a surface-treated steel plate, and the like. Examples of the metal plate for forming the tab 12 include aluminum alloy plates.

As shown in fig. 1 to 3, 5, and 6, the can lid main body 11 includes a panel portion 21, an annular groove portion 22 provided at an outer peripheral edge of the panel portion 21, and a flange portion 23 provided at an outer peripheral edge of the annular groove portion 22.

As shown in fig. 1 to 4, the panel portion 21 is formed in a disc shape. The panel portion 21 includes a score line 31, a rivet portion 32, an auxiliary score line 33, a protector portion 34, and a finger insertion recess 35. Panel portion 21 may have display portion 36 for displaying the contents of can 100, such as braille. The panel portion 21 may have a convex portion or a concave portion for product identification, design, reinforcement, and the like.

As shown in fig. 6, the score line 31 is broken by the opening operation of the tab 12. The score line 31 forms an opening of the can lid 1 in the panel portion 21 by breaking. In other words, the score line 31 surrounds the region to be the opening piece when forming the opening portion of the can lid 1. Since the can lid 1 of the present embodiment is fully opened, the score line 31 is formed in a circular or substantially circular shape as shown in fig. 1, for example. Then, by breaking the score line 31, as shown in fig. 6, the radially inner portion of the score line 31 of the panel portion 21 can be removed as an opening piece together with the rivet portion 32 from the radially outer portion of the score line 31 of the panel portion 21.

The score line 31 is a groove constituting a weak portion which breaks a part of the panel portion 21 in the shape of an opening by an external force. As shown in fig. 3, the score line 31 is, for example, a wedge-shaped groove provided on the outer surface of the panel portion 21, and a part of the panel portion 21 is formed to be thin by the score line 31. Here, the outer surface of the panel portion 21 refers to a main surface exposed to the outside in a state where the can lid 1 is provided on the can body 101 of the can 100, that is, a surface constituting the upper surface of the can 100.

The score line 31 is disposed in the protection portion 34, for example. The score line 31 is not limited to a circular shape, and may have, for example, the following structure: the panel portion 21 is formed in a partially discontinuous arc shape so that most of the panel portion is opened, and the opening piece of the opening is continuous with a part of the panel portion 21.

As shown in fig. 1 to 3, 5, and 6, the rivet portion 32 is provided on one main surface of the panel portion 21, specifically, on the outer surface of the panel portion 21. The rivet portion 32 is provided on the outer peripheral edge side of the panel portion 21 and on the center side of the score line 31. That is, the rivet portion 32 is provided adjacent to the score line 31 on the radially inner side of the score line 31.

The rivet portion 32 is formed in a cylindrical shape protruding from one main surface of the panel portion 21. The rivet portion 32 is formed by drawing a part of the panel portion 21 into a cylindrical shape. The rivet portion 32 is formed by riveting after the tab 12 is disposed, thereby fixing the tab 12 to the panel portion 21. In fig. 1 to 3, 5, and 6, the rivet portion 32 shows a state after the caulking process.

As shown in fig. 1 to 4, the auxiliary score line 33 is formed in the vicinity of the rivet portion 32 of the panel portion 21. The auxiliary score line 33 is partially broken at the time of opening operation of the tab 12. The auxiliary score line 33 includes, for example, a main score line 41 and an auxiliary score line 42 provided on the opposite side of the main score line 41 from the rivet portion 32 and parallel to the main score line 41.

Main score line 41 is a groove constituting a weak portion that breaks a part of panel portion 21 in the shape of an opening portion by an external force. Main score line 41 is, for example, a wedge-shaped groove provided on the outer surface of panel portion 21. A part of panel portion 21 is formed to be thin-walled by main score line 41. As shown in fig. 6, the main score line 41 is broken when the tab 12 is opened, and the rivet portion 32 can be moved upward.

As shown in fig. 4, main score line 41 includes a first portion 41a, a pair of second portions 41b continuous with first portion 41a, and a pair of third portions 41c continuous with the pair of second portions 41b, respectively. First portion 41a, the pair of second portions 41b, and the pair of third portions 41c of main score line 41 are continuous.

As shown in fig. 4, the first portion 41a extends in an arc shape along the rivet portion 32 on the inner side in the radial direction of the panel portion 21 of the rivet portion 32. When a straight line passing through the center of the rivet portion 32 and the tip end of the tab 12 is defined as a first straight line X, and a straight line passing through the center of the rivet portion 32 and orthogonal to the first straight line X is defined as a second straight line Y, the first portion 41a is disposed radially inward of the second straight line Y in the can lid 1. That is, the radius of curvature of the first portion 41a is set to be larger than the radius of the rivet portion 32 before the caulking process.

As shown in fig. 4, the second portions 41b are continuous with the first portions 41a, respectively, and extend in a direction along the second straight line Y. The second portion 41b is formed linearly, for example. The continuous portion of the first portion 41a and the second portion 41b is formed in an arc shape having a predetermined radius of curvature, for example. The second portion 41b is disposed radially inward of the second straight line Y in the cover 1. The distance between the second portion 41b and the second straight line Y in the direction of the first straight line X is preferably in the range of 0.2 to 2.0 mm. As shown in fig. 4, the third portions 41c are continuous with the second portions 41b, and are curved in a direction away from the second straight line Y. The third portion 41c is formed in a plurality of arc shapes having different radii of curvature with a center of curvature at a position inward of the second straight line Y in the radial direction of the tank cover 1, for example. The third portion 41c is disposed radially inward of the second straight line Y in the cover 1.

The auxiliary score line 42 is provided radially inward of the second straight line Y of the main score line 41 in the panel portion 21. Secondary score line 42 is formed parallel to primary score line 41. The secondary score line 42 is, for example, a wedge-shaped groove provided on the outer surface of the panel portion 21. Secondary score line 42 is formed to be shallower in depth than primary score line 41. That is, the thickness of the portion of panel portion 21 where secondary score line 42 is provided is made thicker than the thickness of the portion of panel portion 21 where primary score line 41 is provided. A part of the panel portion 21 is formed to be thin by the secondary score line 42.

As shown in fig. 2 to 6, the protective portion 34 is formed by folding back the panel portion 21 into a ring shape. The protection portion 34 is formed by, for example, being folded back 4 times radially inward of the outer peripheral edge of the panel portion 21 and radially outward of the rivet portion 32. That is, the protective portion 34 is formed by arranging the panel portion 21 in 5 layers. Score lines 31 are formed in the third layer of the panel portion 21 in the protection portion 34.

The protection unit 34 includes: an outer protective portion 34a that protects the inner peripheral edge of the portion of the panel portion 21 that is present in the can body 101, which portion is broken at the score line 31, when the score line 31 is broken by opening the tab 12; and an inner protection portion 34b for protecting an outer peripheral edge of a portion (opening piece) of the panel portion 21 that is broken at the score line 31 and is separated from the can body 101. The outer protective portion 34a is formed of the three-layered panel portion 21, and the folded portion is present at the inner periphery of the open panel portion 21. The inner protective portion 34b is formed of the three-layered panel portion 21, and the folded portion is present at the outer peripheral edge of a portion separated from the opening of the panel portion 21.

In other words, as shown in fig. 3, the protector 34 includes: an upper layer 34c, which is positioned on the outer surface side of the can lid 1, and is formed by the panel portions 21 of the first and second layers that are folded back; a lower layer 34d, which is positioned on the inner surface side of the can lid 1 and is formed by the panel portions 21 of the fourth layer and the fifth layer that are folded back; and an intermediate layer 34e, which is formed by the folded third-layer panel portion 21, and which is located between the upper layer 34c and the

lower layer

34d, 34 e. The outer protective portion 34a is formed of the upper layer 34c and a part of the intermediate layer 34e, and the upper layer 34c is positioned above the score line 31 and functions as a protective portion after the score line 31 is broken. The inner protection portion 34b is formed of a part of the intermediate layer 34e and the lower layer 34d, and the lower layer 34d is positioned below the score line 31 and functions as a protection portion after the score line 31 is broken.

The finger insertion recess 35 is located below the rear end of the tab 12 to which the finger is hooked, and is recessed from the outer surface of the panel portion 21.

The groove 22 is an annular recess provided continuously with the outer peripheral edge of the panel portion 21 and protruding toward the can body side when fixed to the can body. The groove portion 22 has a function of improving the pressure resistance of the can lid 1.

The flange portion 23 is crimped to the open end of the can 101. The flange portion 23 is provided with a sealing resin layer on a surface abutting against the can body 101.

As shown in fig. 1 to 3, the tab 12 includes a mounting portion 51, a distal end portion 52, and a finger hook portion 53. The tab 12 is integrally formed with a mounting portion 51, a tip portion 52, and a finger hooking portion 53. When the tab 12 is opened by a finger or the like hooked on the finger hook portion 53, the distal end portion 52 presses a portion of the panel portion 21 radially inward of the score line 31, thereby breaking the score line 31.

As shown in fig. 3, the mounting portion 51 is formed in a plate shape and has a rivet hole 51a. The attachment portion 51 is continuous with the distal end portion 52 and the finger hook portion 53. The rivet hole 51a is formed to have an inner diameter into which the rivet portion 32 can be inserted. By performing caulking processing on the rivet portion 32 inserted into the rivet hole 51a, the mounting portion 51 is fixed to the panel portion 21 by the rivet portion 32.

The front end portion 52 is formed on the front end side of the tab 12. The shape of the tip portion 52 is formed in an arc shape or a polygon shape. The distal end portion 52 is formed by, for example, double-bending the outer peripheral edge except for the distal end.

The finger hook 53 is a portion for hooking a finger to lift the tab 12 when the opening of the tab 12 is operated. As shown in fig. 1 and 2, for example, the finger hook 53 includes a ring hole 53a and is formed in a ring shape. Specifically, the finger hook 53 is formed in a rectangular frame shape having an arc-shaped corner. The finger hook 53 is formed on the opposite side of the distal end 52 with the attachment 51 interposed therebetween. When the tab 12 is attached to the panel portion 21, the rear end of the finger hooking portion 53 faces the finger insertion recess 35. The finger hook 53 is formed by bending, for example, an outer peripheral edge and an inner peripheral edge of the annular hole 53a in two layers.

As shown in fig. 4, in the can lid 1 configured as described above, the auxiliary score line 33 is located inward of the second straight line Y passing through the center of the rivet portion 32 in the radial direction of the can lid 1. Therefore, the lever action at the time of lifting the tab 12 can be reliably exerted even in a positive pressure state in which the can cover 1 bulges in a dome shape with the center portion of the can cover 1 as a vertex. That is, when the opening operation of the tab 12 is performed, the displacement of the tip end portion 52 of the tab 12 to the outer peripheral side of the can lid 1 can be suppressed. Therefore, when the tab 12 is opened, the tip of the tip portion 52 can press the portion of the panel portion 21 radially inward of the score line 31, and the opening operation can be performed by the appropriate tab 12. Therefore, the can lid 1 can be opened with improved openability even with a positive pressure can, depending on the shape of the auxiliary score line 33 and the positional relationship between the rivet portion 32 and the auxiliary score line 33.

As described above, the can lid 1 according to the embodiment of the present invention has sufficient opening performance even when used for a positive pressure can.

The present invention is not limited to the above embodiments. For example, in the above example, the second portion 41b of the main score line 41 of the auxiliary score line 33 is formed linearly as an example of extending in the direction along the second straight line Y, but the present invention is not limited thereto. The second portion 41b may be curved instead of being linear as long as it can be approximated to extend in the direction along the second straight line Y. When the second portion 41b is curved, the radius of curvature of the second portion 41b is set to be an arc shape larger than the radii of curvature of the first portion 41a and the third portion 41c.

In the above example, the tank cover 1 is used for the positive pressure tank, but the present invention is not limited thereto, and may be used for the negative pressure tank.

The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the gist thereof. In addition, the respective embodiments can be implemented in appropriate combinations, and in this case, combined effects can be obtained. Further, the above-described embodiments include various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed structural elements. For example, even if some of the components are deleted from all the components shown in the embodiments, if the problem can be solved and the effect can be obtained, the structure from which the components are deleted can be extracted as an invention.

Description of the reference numerals

The can lid 1, the can lid body 11, the tab 12 (tab for can lid), the panel 21, the groove 22, the flange 23, the score line 31, the rivet 32, the auxiliary score line 33, the protective 34a, the protective 34b, the upper 34c, the lower 34d, the intermediate 34e, the concave 35 for finger insertion, the display 36, the main score line 41, the first 41a, the second 41b, the third 41c, the auxiliary score line 42, the mounting 51, the rivet hole 51a, the tip 52, the finger hook 53, the ring hole 53a, the can 100, the seaming 100a, and the can body 101.

Claims

1. A can lid, comprising:

a disc-shaped panel portion;

a score line provided on an outer peripheral side of the panel portion;

a rivet portion provided on the panel portion and adjacent to an inner side in a radial direction of the score line;

a tab having an attachment portion having a rivet hole attached to the rivet portion, a leading end portion continuous with the attachment portion, and a finger hook portion formed on an opposite side of the leading end portion with the attachment portion therebetween; and

and an auxiliary score line formed in the panel portion and having a first portion extending in an arc shape along the rivet portion radially inward of the rivet portion and a second portion continuous with the first portion, the second portion extending in a direction along the second straight line and located closer to the center of the panel portion than the second straight line when a straight line passing through a center of the rivet portion and a tip of the tab is a first straight line and a straight line passing through the center of the rivet portion and orthogonal to the first straight line is a second straight line.

2. The can lid of claim 1 wherein,

the distance between the second portion and the second straight line in the extending direction of the first straight line is set to be in the range of 0.2 to 2 mm.