JP5658940B2 - Can lid - Google Patents

Description

  The present invention relates to a can lid that is wound around an open end of a can body.

As a can lid of a beverage can, as shown in Patent Document 1, a steion tab type that can open a drinking mouth with a tab attached to a can lid body is known.
The can lid equipped with this tab has a tab attached by a rivet. By pulling up the lifting part of the tab, the vicinity of the rivet becomes a fulcrum, and the tab nose (the tip of the tab) acts as an action point. The opening piece surrounded by the score is pressed and immersed to break the score, and the opening piece is opened. At this time, the score is separated from the starting end portion and the terminal end portion, and the opening piece is pushed into the beverage can and opened without leaving the can lid.

  The score includes a main score that is broken by pressing the tab to form an opening piece, and an auxiliary score that is formed in parallel adjacent to the inside of the main score and has a smaller depth of cut. The main score and the auxiliary score are connected to each other at the start and end of the score. And the opening piece is formed leaving a part of connection part (hinge part) with the panel surface between this score start end part and termination | terminus part.

  In the can lid configured in this way, in particular, when a tab is raised to open the can, the middle part of the main score near the rivet is first broken (popping operation), and then toward the beginning of the main score. The rupture progresses, and at the same time, the rupture progresses toward the terminal direction of the main score in the opposite direction (tier operation). The break in the start direction of the main score stops immediately because the distance to the start end is short, but the break progresses so as to go around the opening piece in the end direction of the main score. When the opening piece is bent at the hinge portion between and the opening piece completely enters the inside of the can lid, the breakage reaches the end portion and stops.

Japanese Patent No. 3468548

  However, at the time of tearing operation, the resistance increases due to variations in the remaining thickness of the main score, and when a disadvantage occurs in opening the can, the hinge part of the opening piece breaks so as to connect the score end part from the score start end part, When the end of the tab has entered the inside of the can lid before the opening piece has been completely opened, problems such as defective opening may occur.

  The present invention has been made in view of such circumstances, and prevents inadvertent breakage from the score start end portion to the score end portion that occurs in the hinge portion of the opening piece, and ensures a suitable can openability. A can lid is provided.

The can lid of the present invention is formed with a rivet formed to project from the center of the upper surface of the can lid body, an opening piece defined by the main score, and shallower than the main score adjacent to the inside of the main score. An auxiliary score and a tab attached to the rivet with one end overlaid on the opening piece, and pulling the other end of the tab upward, the one end presses the opening piece downward And the main score and the auxiliary score are connected by a transition section that gradually changes from the main score to the auxiliary score at least at the start end. And the starting end portion is formed to be outwardly convex by a continuous body of a plurality of arcs, and the center of an arc that constitutes the outer tip portion that is the furthest away from the rivet among these arcs As rupture, based on a line perpendicular to the longitudinal direction of the tab, the the center of the circular arc around which the transition section is started from the rotational position 100 ° or more in the counterclockwise direction, which is guided along the arc The start point of the transition section is provided so as to avoid the range in which the vector of the traveling direction is in the direction toward the hinge portion .

The break in the start direction of the main score is guided along the main score, but the start point (inflection point) of the transition section from the main score to the auxiliary score approaches the end point of the score. If it exists in the circular arc front-end | tip part near a hinge part, the inflection point will become resistance, a fracture | rupture direction will deviate from a score shape, and it will become easy to crack a hinge part.
In this can lid, avoid the range in which the vector of the direction of break progress guided along the arc provided to be folded back at the score start end is in the direction toward the hinge, and counterclockwise around the center of the arc By providing an inflection point at a position rotated by 100 ° or more, the inadvertent breakage that occurs in the hinge portion is prevented, and the inside of the can lid before the opening piece at the end of the tab is fully opened is prevented. The pressing force can be transmitted effectively, and a suitable openability can be ensured.
In addition, when the main score and the auxiliary score are connected, if the level difference is large, cracks are likely to be formed from that portion, but by providing a transition section connecting with a gentle slope from the main score to the auxiliary score, it is ensured. The occurrence of cracks can be prevented, and suitable openability can be obtained. This transition section is preferably 1 to 2 mm.

  According to the present invention, it is possible to prevent inadvertent breakage from the score start end portion to the score end portion that occurs in the hinge portion of the opening piece, and to ensure a suitable can openability.

It is a top view which shows the can lid of this embodiment. It is AA sectional drawing of the can lid shown in FIG. It is a principal part enlarged view explaining the inflection point of a main score and an auxiliary score. It is sectional drawing explaining the transition area of a main score and an auxiliary score. It is sectional drawing explaining a score shape, (a) is XX sectional drawing of the main score shown in FIG. 4, (b) is YY sectional drawing of the auxiliary | assistant score shown in FIG.

Hereinafter, an embodiment of a can lid of the present invention will be described with reference to the drawings.
The can lid 100 of the present embodiment is a so-called stab tub type can lid used for beverage cans, and is composed of a can lid body 1 and a tab 2 as shown in FIG. The main body 1 and the tab 2 are each formed of an aluminum alloy.

  As shown in FIGS. 1 and 2, the can lid main body 1 has a disk-shaped panel portion 10a disposed in the central portion thereof, and continues downward from the outer peripheral edge of the panel portion 10a via the corner portion 11. A counter sink portion 13 that forms a ring-shaped recess 12 facing the chuck, a chuck wall portion 14 that extends from the outer peripheral edge of the counter sink portion 13 while increasing in diameter upward, and a shoulder that extends from the outer peripheral edge of the chuck wall portion 14. It is composed of a portion 15 and a shoulder curl portion 16 continuous with the shoulder portion 15.

As shown in FIG. 1, a rivet 3 is formed on the upper surface of the panel portion 10 a so as to protrude from the center portion of the panel portion 10 a (can lid main body 1). A tab 2 is attached to the rivet 3. Further, an opening piece 5 defined by the score portion 4 is formed in a portion extending in a specific radial direction from the rivet 3 on the upper surface of the panel portion 10a (the lower side of the rivet 3 in FIG. 1). A finger-hanging recess 6 is formed on the opposite side (the upper side of the rivet 3 in FIG. 1) through 3, and a pair of protrusions 7 called dimples are formed between the rivet 3 and the finger-holding recess 6. ing.
A concave panel deboss 10b is formed extending in the length direction of the tab 2 so as to surround the opening piece 5, the finger hook concave portion 6, and the convex portion 7, and is formed by the outer peripheral wall 10c constituting the panel deboss 10b. The rigidity of the whole panel part 10a is improved.

The tab 2 is formed flat by cutting out a metal plate such as aluminum, and is formed on the opposite side across the rivet 3 with the one end 21 disposed so as to overlap the opening piece 5. The other end part is provided with a lifting part 22, and the lifting part 22 is formed with a tab hole part 23 that opens in the thickness direction of the tab 2. A tongue portion 24 is formed by a U-shaped slot 24a between the one end portion 21 and the lifting portion 22, and a rivet hole is formed in the tongue portion 24. The rivet 3 is inserted into the rivet hole and the tongue is formed. The tab 2 is attached in a state where the lower surface of the portion 24 is in contact with the surface of the panel deboss 10b.
The rivet 3 is formed by applying a coining process in which the periphery of the center of the panel portion 10a is pressed in a ring shape from above to project the center portion of the panel portion 10a upward.

As shown in FIG. 1, the score portion 4 includes a start end portion 41, a concave arc portion 42 that is an arc-shaped initial fracture portion that substantially halves the rivet 3, a substantially elliptical intermediate portion 43, and a termination portion 44. The opening piece 5 is defined by leaving a part of the hinge portion 45 that is a connection portion with the panel portion 10 a between the start end portion 41 and the end portion 44. The concave arc portion 42 is formed in a ring-shaped coined portion that is crushed by coining around the rivet 3.
Moreover, the score part 4 is a double structure provided with the main score 4a which is fractured | ruptured by the press by the tab 2, and forms the opening piece 5, and the auxiliary score 4b formed in parallel adjacent to the inside of the main score 4a. The main score 4 a and the auxiliary score 4 b are connected to each other at the start end 41 and the end end 44 of the score portion 4.
As shown in FIG. 5, the main score 4a and the auxiliary score 4b are each formed in an inverted trapezoidal shape, and the side surface of the auxiliary score 4b is provided continuously with a part of the side surface of the main score 4a. In addition, the auxiliary score 4b is formed shallower than the adjacent main score 4a and has a bottom surface wider than the main score 4a, and is not broken by pressing of the tab 2.

As shown in FIG. 3, the start end portion 41 is formed to be convex outward by a continuous body of a plurality of arcs, and has an arc shape larger than the interval between the main score 4 a and the auxiliary score 4 b. The terminal portion 44 has an arc shape having a diameter that is substantially the same as the distance between the main score 4a and the auxiliary score 4b.
As shown in FIG. 4, the connection between the main score 4 a and the auxiliary score 4 b at the start end 41 is performed mainly from the start point P (inflection point) to the end point E by a transition section L of a predetermined length that gradually changes. The bottom surface 40a of the score 4a and the bottom surface 40b of the auxiliary score 4b are connected by a gentle inclined surface 40 and are gradually changed.

The starting point P is a circular arc with reference to a line (reference line B) that passes through the center C of the arc that forms the outer tip of the starting end 41 that is farthest from the rivet 3 and is perpendicular to the longitudinal direction of the tab 2. Arranged at a position (angle θ) rotated about 100 ° counterclockwise around the center C, the transition section L is started from this starting point P.
The remaining thickness t1 of the main score 4a of the starting end 41 is 0.08 to 0.13 mm with respect to the original plate thickness t0 = 0.235 mm, and the remaining thickness t2 of the auxiliary score 4b is the remaining thickness of the main score 4a. It is set larger by 0.046 to 0.056 mm than t1. Moreover, the transition section L in this case is set to 1 to 2 mm.

An inner bead 8 that protrudes along the score portion 4 is formed on the opening piece 5 to reinforce the opening piece 5.
When the pull-up recess 22 of the tab 2 is lifted, the finger-hanging recess 6 is arranged to facilitate the pull-up by placing a fingertip below the pull-up portion 22, and to the panel portion 10 a near the pull-down portion 22. Is formed.
Further, the side surface 61 of the finger hooking recess 6 is provided continuously with a part of the outer peripheral wall 10c of the panel deboss 10b, and the bottom surface 62 is formed so as to be further depressed downward from the upper surface of the panel deboss 10b.

  Two protrusions 7 protrude from the upper surface of the panel deboss 10 b and are formed in the width direction of the tab 2 at intervals. And the outer edge part of the tab 2 is hooked on this pair of convex part 7, and the rotation movement of the tab 2 can be prevented now.

  In the can lid 100 configured as described above, when the pulling portion 22 of the tab 2 is pulled upward, first, the rivet 3 is lifted upward with the one end portion 21 of the tab 2 on the opening piece 5 as a fulcrum. As a result, the rivet 3 side of the concave arc portion 42 is lifted upward in a state where the opening piece 5 side of the concave arc portion 42 of the main score 4a is pressed by the tab 2, and a shearing force acts on the concave arc portion 42 and breaks. (This is the pop operation.) When the tab 2 is further lifted, the rivet 3 serves as a fulcrum, the action point becomes one end 21 of the tab 2, and the opening piece 5 surrounded by the main score 4a is pushed into the can by the tab 2 while the main score. 4a sequentially breaks and opens (the pop operation is the tear operation).

At this time, the main score 4a is also slightly broken in the starting direction from the pop operation to the tear operation. The main score 4 a is formed so as to be folded back along the arc of the start end portion 41, and the vector in the breaking progress direction is directed toward the hinge portion 45 in the upper half of the arc portion. For this reason, if there is a starting point P (inflection point) of the transition section L of the main score 4a and the auxiliary score 4b in this part, that part becomes resistance, and the breaking direction tends to deviate from the arc of the main score 4a. Therefore, the starting point P needs to be disposed at least below the reference line B. However, if the angle θ from the reference line B is less than 100 °, the start point P may deviate from the main score 4a and cause a crack.
In the can lid 100 of the present embodiment, the starting point P is based on a line (reference line B) that passes through the center C of the arc that forms the outer tip of the starting end 41 and is perpendicular to the longitudinal direction of the tab 2. Since the transition section L is started from the start point P of the position rotated about 100 ° (angle θ) counterclockwise around the arc center C, inadvertent breakage occurring in the hinge portion 45 is reliably prevented, The penetration into the inside of the can lid 100 before the opening piece 5 of the one end portion 21 of the tab 2 is completely opened is prevented.
Thus, since the pressing force by the tab 2 can be transmitted effectively, a suitable openability can be ensured.

  Further, when the main score 4a and the auxiliary score 4b are connected, if the level difference is large, cracks are likely to be generated from that portion. By providing the transition section L that transitions on the inclined surface 40, the occurrence of cracks is reliably prevented.

Next, with respect to the can lid 100 configured as described above, various samples are prepared under the conditions shown in Table 1 for the position of the angle θ of the starting point P between the main score 4a and the auxiliary score 4b at the starting end 41 of the score unit 4. It produced and it was confirmed whether the hinge part 45 would crack at the time of can opening.
“Angle θ (°)” in Table 1 corresponds to the angle θ shown in FIG. Further, the remaining thickness t1 of the main score 4a of the starting end 41 is 0.13 mm with respect to the original plate thickness t0 = 0.235 mm, and the remaining thickness t2 of the auxiliary score 4b is 0.046 to less than the remaining thickness t1 of the main score 4a. The transition section L from the start point P to the end point E was set to 1.5 mm.
“O” shown in the column “Crack occurrence” in Table 1 indicates that cracks are generated when the can is opened using a can lid in which the remaining thickness of the main score is 3 μm thicker than the standard upper limit (0.13 mm). This indicates that no cracks occurred in the hinge portions 45 of all 20 cans. In addition, “△” indicates that the evaluation of “◯” was not obtained with the can lid in which the remaining thickness of the main score was 3 μm thicker than the standard upper limit value, but the can lid made with the remaining thickness of the main score at the standard upper limit value. As a result of re-evaluation, no cracks were found in the hinges of all 20 cans. In addition, “×” indicates that at least one of the 20 cans was cracked even in the re-evaluation.

As shown in Table 1, in the case where the starting point P is in the range of 100 ° or more, even if the remaining thickness of the main score is 3 μm thicker than the standard upper limit value, there was no crack in the hinge part. In the range of 70 to 90 °, some cracks were observed in the remaining thickness 3 μm thicker than the standard upper limit value, but no crack occurred in the remaining standard thickness value. In the range of 0 to 60 °, the hinge part was cracked even with the remaining thickness at the upper limit of the standard.
As described above, by setting the angle position θ of the start point P of the transition section L from the main score 4a to the auxiliary score 4b to 100 ° or more, inadvertent breakage (cracking) that occurs in the hinge portion 45 is surely prevented. It was confirmed that it was possible.

  In addition, this invention is not limited to the thing of the structure of the said embodiment, In a detailed structure, a various change can be added in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 100 Can lid 1 Can lid main body 2 Tab 3 Rivet 4 Score part 4a Main score 4b Auxiliary score 5 Opening piece 6 Finger recessed part 7 Convex part 8 Inner bead 10a Panel part 10b Panel debossed 10c Outer peripheral wall 11 Corner part 12 Annular recessed part 13 Counter sink Part 14 chuck wall part 15 shoulder part 16 shoulder curl part 21 one end part 22 lifting part 23 tabhole part 24 tongue part 40 inclined surface 40a, 40b bottom face 41 start end part 42 concave arc part 43 intermediate part 44 termination part 45 hinge part 61 side part 62 Bottom

Claims (2)

A rivet formed to project from the center of the upper surface of the can lid body, an opening piece defined by a main score, an auxiliary score formed adjacent to the inside of the main score and shallower than the main score, and the opening A tab attached to the rivet with one end overlapped on the piece, and pulling the other end of the tab upward, the one end presses the opening piece downward to break the main score The main score and the auxiliary score are connected by a transition section that gradually changes from the main score to the auxiliary score at least at the start end, and the start end Is formed so as to be convex outward by a continuous body of a plurality of arcs, and passes through the center of the arc that forms the outer tip portion that is the farthest away from the rivet among these arcs, and the tab Relative to the line perpendicular to the longitudinal direction, about the center of the arc being the transition interval starts from the rotational position 100 ° or more in the counterclockwise direction, the traveling direction of the vector of the fracture to be guided along the circular arc The can lid is characterized in that a starting point of the transition section is provided avoiding a range in which the direction toward the hinge portion .   The can lid according to claim 1, wherein the transition section is formed with a length of 1 to 2 mm.

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