JP7295396B2 - can lid - Google Patents

Description

The present invention relates to can lids.

The technology disclosed in Patent Document 1 below is called a push end, and is a technology invented before the emergence of pull tabs.
In this technique, the opening that will become the drinking mouth is cut in advance, leaving a part, and then the cut opening is sealed with resin.
The features of this technology are that the can can be opened by pushing in the opening and that the sealability can be secured. In particular, it was put into practical use for carbonated beverages for a period of time, because it is possible to ensure airtightness by using internal pressure in cans of internal pressure such as beer and carbonated beverages.
A problem with this technology is that, since the opening is opened by pushing it with a finger, if foreign matter or oil adheres to the finger, the foreign matter or oil may come into contact with the beverage. In this case, the hygiene and safety of the beverage may be affected.
Therefore, this technology was replaced by so-called tabs. Can lids utilizing tabs have scores formed on the surface of the can lid. A portion of the can lid is pushed by the tab to break the score and open the mouthpiece.

JP-A-51-12285

However, with a can lid that simply utilizes a tab, such as the conventional can lid, if the can lid is made of a steel plate or the like, rust may occur on the surface of the score.

SUMMARY OF THE INVENTION The present invention has been made in view of the circumstances described above, and an object of the present invention is to suppress the generation of rust while ensuring the cleanliness of the contents of a can.

In order to solve the above problems, the present invention proposes the following means.
A can lid according to the present invention includes a can lid body having an opening formed therein, a portion of which is connected to the can lid body, and an outer peripheral edge of the can lid body that is formed on the lower surface of the can lid body in a state in which the opening is closed from below. a closure piece that overlaps with the can lid body; a fixing agent that secures the outer peripheral edge of the closure piece to the lower surface of the can lid body; Adjacent rivets and fixed to the rivets, with a first end overlapping the upper surface of the closure piece and a second end positioned opposite the first end with the rivet therebetween. A can lid for an internal pressure can, comprising: a tab, wherein the closure piece is larger than the opening in a plan view, and an overlapping portion where the can lid main body and the closure piece overlap each other extends along the circumferential direction. The width along the radial direction of the opening increases as the distance from the connecting portion increases, and the outer peripheral edge of the closing piece extends continuously in the circumferential direction of the opening in a plan view of the can lid body. The adhesive is formed in a C shape opening at the connecting portion, the adhesive is formed in the C shape along the outer peripheral edge of the blocking piece, and the outer peripheral edge of the blocking piece A pair of circumferential end portions adjacent to each other in the direction, and a central portion sandwiched between the pair of circumferential end portions in the circumferential direction, wherein the circumferential end portion extends from the connecting portion of the outer circumferential edge to the connecting portion. The distance in the direction is 20% or less of the entire portion, and the fixing strength between the can lid body and the closure piece at the peripheral end portion is greater than the adhesion strength between the can lid body and the closure piece at the central portion. is also low .
The can lid body includes a panel portion and a flange portion, and an annular recess is disposed between the flange portion and the panel portion, and the annular recess is formed in an annular shape coaxial with the axis. The bottom surface of the annular recess may be positioned below both the flange portion and the panel portion.
The can lid may be tinplate, tin-free steel, nickel-plated steel plate, or stainless steel.

When the user lifts (raises) the second end of the tab starting from the rivet, the first end of the tab descends starting from the rivet. This causes the first end to push down the closure piece. Then, of the adhesive, for example, a portion adjacent to the connecting portion between the can lid body and the closure piece is first broken, and then this break is propagated to other portions of the adhesive. As a result, the fracture spreads over the entire fixing agent. As a result, the first end of the tab pushes down on the closure piece while entering the opening, opening the opening and opening the can lid.
With this can lid, the can lid is opened by raising the tab. Therefore, for example, even if foreign matter, oil, or the like adheres to a finger, the foreign matter, oil, or the like is unlikely to come into contact with the contents in the can. Therefore, the cleanliness (hygiene and safety) of the contents can be ensured.
An adhesive adheres the outer peripheral edge of the closure piece to the lower surface of the can lid body. Therefore, the adhesive covers the outer peripheral edge of the blocking piece and prevents the outer peripheral edge of the blocking piece from being exposed. As a result, for example, even if the blocking piece is made of a steel plate or the like, the generation of rust on the blocking piece can be prevented.

Of the outer periphery of the blocking piece, the fixing strength at the peripheral end is lower than the fixing strength at the central portion. Therefore, when the user pulls up the tab and the tab transmits a downward force to the closure piece, the portion of the adhesive that adheres the outer peripheral edge of the closure piece to the can lid body is likely to break. Become. Therefore, for example, even if the pulling force of the tab is small, the fixing agent can be easily broken, and the operability of opening the can lid can be improved.

ADVANTAGE OF THE INVENTION According to this invention, generation|occurrence|production of rust can be suppressed, ensuring the cleanliness of the contents of a can.

1 is a plan view of a can lid according to one embodiment of the present invention; FIG. FIG. 2 is an enlarged view of a main part in the plan view shown in FIG. 1; It is a figure which shows the state which removed the tab from the enlarged view shown in FIG. FIG. 2 is a sectional view taken along line IV-IV in FIG. 1; 5 is an enlarged view of a main part in the cross-sectional view shown in FIG. 4; FIG. It is the perspective view which looked at the principal part of the can lid shown in FIG. 1 from the lower side. 1. It is a figure explaining 1 process of the method of manufacturing the can lid shown in FIG. 1, Comprising: It is sectional drawing which shows the state which expanded some base materials. FIG. 8 is a view for explaining one step of the method of manufacturing the can lid shown in FIG. 1, and is a cross-sectional view showing a state in which a part of the base material is cut after the state shown in FIG. 7; It is a top view of the can lid concerning the modification of the present invention. FIG. 10 is an enlarged view of a main part in the plan view shown in FIG. 9;

A can lid 10 according to an embodiment of the present invention will now be described with reference to FIGS. 1 to 8. FIG.
The can lid 10 is attached to the open end of the cylindrical can body. The can lid 10 constitutes a can together with a bottomed cylindrical can body. As the can body, a configuration in which the body and the bottom are integrally formed, or a configuration in which the body and the bottom are formed as separate members and then assembled can be adopted. The can is a so-called steel can. The can lid 10 has a so-called easy open end structure.

As shown in FIGS. 1 to 5 , the can lid 10 includes a can lid body 11 , a closure piece 12 , an adhesive 13 , rivets 14 and tabs 15 .
The can lid main body 11, the closing piece 12 and the rivet 14 are integrally formed of steel plate such as tin plate. In addition, the said steel plate is not restricted to tinplate. As the steel sheet, for example, tin-free steel, nickel-plated steel sheet, stainless steel, or the like can be employed.

The can lid body 11 is formed in a circular shape (perfectly circular shape) in plan view. Hereinafter, the center line passing through the center of the can lid body 11 in plan view is referred to as the axis O of the can lid 10 . The direction of the axis O is the vertical direction Z when the can is upright. At this time, the can body is positioned below the can lid 10 along the direction of the axis O, and the can lid 10 is positioned above the can body.

The can lid body 11 includes a panel portion 21 and a flange portion 22 . The panel portion 21 is formed in a circular shape in plan view. The flange portion 22 extends from the outer peripheral edge of the panel portion 21 over the entire circumference. The flange portion 22 is formed in an annular shape in plan view. The flange portion 22 forms the outermost periphery of the can lid body 11 . The flange portion 22 is assembled to the can body. As shown in FIG. 4 , the flange portion 22 is positioned above the panel portion 21 .

An annular recess 23 is arranged between the flange portion 22 and the panel portion 21 . The annular recess 23 is formed in an annular shape coaxial with the axis O. As shown in FIG. The bottom surface of the annular recess 23 is located below both the flange portion 22 and the panel portion 21 . In other words, the position of the bottom surface of the annular recess 23 is lower than the positions of the flange portion 22 and the panel portion 21 .

As shown in FIGS. 1 to 3, the panel portion 21 has an opening 24 formed therein. The opening 24 is shifted with respect to the axis O in plan view. Hereinafter, the direction in which the opening 24 is positioned with respect to the axis O in plan view is referred to as the front side X1. The direction in which the axis O is positioned with respect to the opening 24 in plan view is referred to as the rear side X2.
In the illustrated example, the opening 24 is formed in a circular shape in plan view. The diameter of the opening 24 is, for example, less than half the diameter of the panel portion 21 .

The closure piece 12 is formed integrally with the can lid body 11 as described above. A portion of the closure piece 12 (hereinafter referred to as a root portion 31 ) is connected to the can lid body 11 . As shown in FIG. 3, the root portion 31 is a portion of the blocking piece 12 located on the rear side X2. The blocking piece 12 is larger than the opening 24 in plan view. The outer peripheral edge 12 a of the closure piece 12 overlaps the opening peripheral edge of the opening 24 on the lower surface of the can lid body 11 .

The connecting portion 16 between the can lid body 11 and the closure piece 12 extends linearly in the left-right direction Y orthogonal to the front-rear direction X when the can lid body 11 is viewed from above. The connecting portion 16 serves as a starting point (hinge) when the blocking piece 12 descends as described later.
The outer peripheral edge 12a of the closure piece 12 continuously overlaps the lower surface of the can lid body 11 in the circumferential direction. An outer peripheral edge 12a of the blocking piece 12 is formed in a C shape continuously extending in the circumferential direction of the opening 24 in plan view. The C-shape opens toward the rear side X2 at the connecting portion 16 .

As shown in FIGS. 4 and 5, the closing piece 12 covers the opening 24 from below. The closing piece 12 closes the opening 24 from below. Since the closing piece 12 closes the opening 24 from below, the closing piece 12 is prevented from rising unexpectedly even when the can is filled with carbonated beverages and the pressure inside the can increases. be done. At this time, although the pressure inside the can acts on the closure piece 12, the pressure inside the can is received by the whole can because the closure piece 12 comes into contact with the can lid body 11. - 特許庁As a result, unintended opening of the opening 24 is restricted.

As shown in FIGS. 1 to 3, the overlapping portion 17 where the can lid body 11 and the closure piece 12 overlap each other has a C-shape extending continuously in the circumferential direction of the opening 24 in a plan view of the can lid body 11 . formed. As shown in FIG. 3 , the C-shape opens toward the rear side X2 at the connecting portion 16 . The size W (width) of the overlapping portion 17 along the radial direction of the opening portion 24 increases as the distance from the connecting portion 16 increases along the circumferential direction.

As shown in FIGS. 4 and 5 , the adhesive 13 adheres the outer peripheral edge 12 a of the closure piece 12 and the lower surface of the can lid body 11 . The adhesive 13 is arranged along the outer peripheral edge 12 a of the blocking piece 12 . The adhesive 13 is formed in a C shape continuously extending in the circumferential direction of the opening 24 in plan view. The C-shape opens at the connecting portion 16 and opens toward the rear side X2.

In this embodiment, the interfacial fracture strength between the can lid body 11 or the closure piece 12 and the adhesive 13 is higher than the cohesive fracture strength of the adhesive 13 . When the lid is opened, cohesive failure (material failure) of the sticking agent 13 occurs before interfacial failure between the can lid body 11 or the closure piece 12 and the sticking agent 13 occurs. As the fixing agent 13, for example, vinyl chloride resin (vinyl chloride resin), polyester resin, epoxy resin, phenol resin, or the like can be used.

The rivet 14 is provided on the upper surface of the can lid body 11 . As shown in FIG. 3, the rivet 14 is adjacent to the connecting portion 16 from the rear side X2. The rivet 14 protrudes upward from the can lid body 11 .
As shown in FIG. 1, tab 15 is a so-called stay-on tab and is fixed to rivet 14 . The tab 15 is long in the front-rear direction X in plan view. The rivet 14 attaches the tab 15 to the can lid body 11 at the portion located between the end 15a (first end) on the front side X1 and the end 15b (second end) on the rear side X2. Fixed. An end portion 15 a (first end portion) of the tab 15 on the front side X<b>1 overlaps the upper surface of the root portion 31 of the closing piece 12 . The end 15a on the front side X1 is located on the rear side X2 with respect to the axis of the opening 24 (opening axis). A finger hole is formed in the end 15b (second end) of the tab 15 on the rear side X2. The end 15b of the rear side X2 is located on the opposite side of the end 15a of the front side X1 with the rivet 14 interposed therebetween.

By the way, as shown in FIG. Each of the pair of peripheral end portions 18 is circumferentially adjacent to the connecting portion 16 between the can lid body 11 and the closure piece 12 . The central portion 19 is sandwiched between the pair of peripheral end portions 18 in the circumferential direction.

In the can lid 10 as shown in FIGS. 1 to 3, when the user pulls up (raises) the end 15b of the rear side X2 of the tab 15 with the rivet 14 as a starting point, the end 15a of the front side X1 of the tab 15 is pulled up. Starting from the rivet 14, it descends. As a result, the end portion 15a on the front side X1 pushes down the closing piece 12. As shown in FIG. Then, of the adhesive 13, for example, the portion adjacent to the connecting portion 16 between the can lid body 11 and the closure piece 12 (the portion of the adhesive 13 that fixes the peripheral end portion 18 (hereinafter referred to as the first portion 13a) )) is first broken, and then this breakage is propagated to another portion of the adhesive 13 (the portion of the adhesive 13 that fixes the central portion 19 (hereinafter referred to as the second portion 13b)). As a result, the fracture spreads over the entire fixing agent 13 . As a result, the end 15a of the front side X1 of the tab 15 pushes down the closing piece 12 while entering the opening 24, and the opening 24 is opened and the can lid 10 is opened.

In this embodiment, the fixing strength of the fixing agent 13 between the can lid body 11 and the closure piece 12 at the peripheral end portion 18 (hereinafter referred to as the fixing strength at the peripheral end portion 18) is the same as that of the can lid body 11 at the central portion 19. It is lower than the fixing strength of the fixing agent 13 to the blocking piece 12 (hereinafter referred to as the fixing strength at the central portion 19). In addition, it can be said that the fixing strength at the peripheral end portion 18 is the fixing strength by the first portion 13a. It can also be said that the fixing strength at the central portion 19 is the fixing strength by the second portion 13b.

Here, the fixing strength is an index that quantifies the openability (the ease of opening the lid). The fixing strength is defined as the first part 13a or the second part 13a or the second part 13b of the fixing agent 13 being broken by pulling up the tab 15 and pushing down the blocking piece 12 by the tab 15. This is the maximum value of the external force (pulling force) applied to pull up the tab 15 during the period from the start of breaking of the tab 13b to the completion thereof.

The fixing strength can be adjusted by the thickness of the fixing agent 13, for example. That is, the cohesive failure of the sticking agent 13 starts from the end face (upper end face) of the sticking agent 13 that is in contact with the closure piece 12 and the can lid body 11 . A fracture surface formed by cohesive failure grows inward from the end face of the adhesive 13 and reaches the lower end face of the adhesive 13 (the end face opposite to the starting point). As a result, the adhesive 13 is completely broken in the vertical direction Z, and the lid is opened.

Therefore, the fixing strength (openability (ease of opening when the cover is opened)) depends on the length of the fractured surface of the adhesive 13 in the cohesive fracture. Therefore, the fixing strength can be adjusted according to the thickness of the adhesive 13 to be applied. That is, when the adhesive 13 to be applied is thick, the length of the fractured surface is increased.
Therefore, in order to make the fixing strength at the peripheral end portion 18 lower than the fixing strength at the central portion 19, for example, the thickness of the adhesive 13 at the peripheral end portion 18 (thickness of the first portion 13a) It may be made thinner than the thickness of the adhesive 13 in the portion 19 (thickness of the second portion 13b).

The fixing strength of the fixing agent 13 depends not only on the thickness of the fixing agent 13 but also on the cohesive failure strength. The cohesive failure strength can be adjusted according to the type of the fixing agent 13 .
Therefore, in order to make the fixing strength at the peripheral end portion 18 lower than the fixing strength at the central portion 19, for example, the fixing agent 13 is by making the cohesive failure strength of the adhesive 13 (first portion 13a) used in the peripheral end portion 18 lower than the cohesive failure strength of the adhesive 13 (second portion 13b) used in the central portion 19. good too.

In the present embodiment, the peripheral end portion 18 refers to a portion of the outer peripheral edge 12a of the blocking piece 12 whose distance in the peripheral direction from the connecting portion 16 is 20% or less of the whole. In other words, the fixing strength at the peripheral end portion 18 can be said to be the fixing strength for a portion of the outer peripheral edge 12a of the blocking piece 12 whose circumferential distance from the connecting portion 16 is 20% or less of the entire portion. In addition, the fixing strength in the central portion 19 is determined by the fixing strength of the portion (remaining 80% portion) of the outer peripheral edge 12a of the blocking piece 12, which is more than 20% away from the connecting portion 16 in the circumferential direction. It can be said that it is strength. The peripheral end portion 18 is located on the rear side X2 of the edge of the tab 15, which is located on the front side X1.

The adhesion strength at the peripheral end portion 18 and the adhesion strength at the central portion 19 can be measured by the following method using, for example, a commercially available tensile tester.
That is, first, the chuck of the tensile tester and the tab 15 of the can lid 10 are connected with, for example, a wire or a chain. When the chuck is pulled up, the tab 15 is pulled up and the adhesive 13 is broken. At this time, the adhesive 13 is broken in the order of the first portion 13a and the second portion 13b. Therefore, the vicinity of the blocking piece 12 is photographed by, for example, a high-speed camera or the like. A period from the start to the end of breaking (hereinafter referred to as a second period) is acquired. Separately, the test result (pull-up strength) of the pull-up tester is obtained. From these results, the maximum pull-up strength in the first period can be taken as the fixing strength at the peripheral end portion 18, and the maximum pull-up strength in the second period can be taken as the fixing strength at the central portion 19. FIG.

As shown in FIG. 6, it can be said that the fixing strength at the peripheral end portion 18 is lower than the fixing strength at the central portion 19 because the weakened portion 13c is formed in the first portion 13a. The weakened portion 13c is a portion of the adhesive 13 that has a lower fixing strength than the portion other than the weakened portion 13c. The weakened portion 13c can be formed, for example, by making the adhesive 13 thinner than other portions.

The blocking piece 12 is formed by, for example, the following method.
The can lid body 11 and the closure piece 12 are formed from a single steel plate 41 (base material) as shown in FIG. As shown in FIG. 7, a steel plate 41 is formed with a bulging portion 42 directed upward. Thereafter, as shown in FIG. 8, the lower end portion of the bulging portion 42 is cut in the circumferential direction of the bulging portion 42, leaving a portion 42a. Thereafter, a force is applied to the bulging portion 42 from above to flatten the bulging portion 42 . Thereby, the opening 24 and the closing piece 12 are formed.

As described above, according to the can lid 10 according to the present embodiment, the can lid 10 is opened by raising the tab 15 . Therefore, for example, even if foreign matter, oil, or the like adheres to a finger, the foreign matter, oil, or the like is unlikely to come into contact with the contents in the can. Therefore, the cleanliness (hygiene and safety) of the contents can be ensured.
An adhesive 13 adheres the outer peripheral edge 12 a of the closure piece 12 and the lower surface of the can lid body 11 . Therefore, the adhesive 13 covers the outer peripheral edge 12a of the blocking piece 12, and the exposure of the outer peripheral edge 12a of the blocking piece 12 is prevented. As a result, for example, even if the blocking piece 12 is made of a steel plate or the like, the generation of rust on the blocking piece 12 can be prevented.

The fixing strength at the peripheral end portion 18 of the outer peripheral edge 12 a of the blocking piece 12 is lower than the fixing strength at the central portion 19 . Therefore, when the user pulls up the tab 15 and the tab 15 transmits a downward force to the blocking piece 12, the first portion 13a of the adhesive 13 is easily broken. Therefore, for example, even if the pull-up force of the tab 15 is small, the adhesive 13 can be easily broken, and the operability of opening the can lid 10 can be improved.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

Like the can lid 10A according to the modification shown in FIGS. 9 and 10, the opening 24 does not have to be circular in plan view. In the can lid 10A, the opening 24 is formed in a rectangular shape elongated in the front-rear direction X in plan view.

In addition, it is possible to appropriately replace the constituent elements in the above-described embodiment with well-known constituent elements without departing from the spirit of the present invention, and the modifications described above may be combined as appropriate.

10, 10A can lid 11 can lid body 12 closure piece 13 adhesive 14 rivet 15 tab 15a front end (first end)
15b rear end (second end)
16 Connecting portion 18 Peripheral end portion 19 Central portion 24 Opening portion 31 Root portion (part of blocking piece)

Claims (3)

a can lid body having an opening;
a closure piece partly connected to the can lid body and having an outer peripheral edge overlapping the lower surface of the can lid body in a state of closing the opening from below;
a fixing agent for fixing the outer peripheral edge of the closure piece and the lower surface of the can lid body;
a rivet provided on the upper surface of the can lid body and adjacent to a connecting portion between the can lid body and the closure piece;
a tab fixed to the rivet and having a first end overlapping the upper surface of the closure piece and a second end opposite the first end with the rivet therebetween. , a can lid for an internal pressure can ,
The blocking piece is larger than the opening in plan view,
The overlapped portion where the can lid body and the closure piece overlap increases in width along the radial direction of the opening as it moves away from the connecting portion in the circumferential direction,
The outer peripheral edge of the closure piece is formed in a C shape that extends continuously in the circumferential direction of the opening and opens at the connecting portion in a plan view of the can lid body,
the adhesive is formed in a C shape along the outer peripheral edge of the blocking piece;
The outer peripheral edge of the blocking piece is
a pair of circumferential end portions adjacent to the connecting portion in the circumferential direction;
a central portion sandwiched in the circumferential direction between the pair of peripheral end portions,
The peripheral end is a portion of the outer peripheral edge where the distance in the peripheral direction from the connecting portion is 20% or less of the whole,
The fixing strength between the can lid body and the closure piece at the peripheral end portion is lower than the adhesion strength between the can lid body and the closure piece at the central portion.
The can lid of the description characterized by : The can lid body includes a panel portion and a flange portion,
An annular concave portion is arranged between the flange portion and the panel portion,
The annular recess is formed in an annular shape coaxial with the axis,
2. The can lid according to claim 1, wherein the bottom surface of said annular recess is positioned below both said flange portion and said panel portion. The can lid according to claim 1 or 2, wherein the can lid is made of any one of tinplate, tin-free steel, nickel-plated steel plate, and stainless steel.

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