JP6836895B2 - Can lid - Google Patents

Description

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

As shown in Patent Document 1 and Patent Document 2, as a can lid for a beverage, a stayion tab type that can open a drinking spout with the tab attached to the can lid main body is known. In the can lid equipped with this tab, the tab is attached by a rivet, and by pulling up the pulling part of the tab, the vicinity of the rivet becomes a fulcrum, and the tab nose part (the tip of the tab) becomes an action point on the panel surface. The opening (opening piece) surrounded by the score is pressed and immersed to break the score and open the opening. At this time, since the start end and the end of the score are provided apart from each other, the opening is pushed into the can without being separated from the can lid to open the can.

By the way, in this type of can lid, in order to obtain good pouring property of the contents, it is possible to increase the opening area of the opening as described in, for example, Patent Document 1 or Patent Document 2. It is done.
In Patent Document 1, the main opening (first opening) defined by the main score (first score) and the area opposite to the main opening with the rivet sandwiched are projected on the upper surface of the can lid main body. A can lid in which a ventilation opening (second opening) defined by a sub-score (second score) is formed is described. Further, in Patent Document 1, the main opening of the can lid and the ventilation opening are connected via a bent portion, the other end of the tab is pulled up, the main score is broken, and the opening is opened. It is described that sometimes, by concentrating stress on the bent portion and breaking the bent portion, the ventilation opening is surely opened as the starting point at which the sub-score breaks the bent portion, and good pouring property is obtained. There is.

Further, in the can lid described in Patent Document 2, the opening formed in the can lid main body is defined by the first score and the third score, and the main opening (first) in which one end side of the tab overlaps. An opening) and a secondary opening (second opening) defined by a second score and a third score and formed in a region opposite the main opening with a rivet in between. , The first score and the second score are connected by the third score, and the main opening and the sub-opening are formed in the opposite region sandwiching the rivet. Then, in Patent Document 2, a large opening composed of a main opening and a sub-opening is formed in the can lid by breaking the score over the entire length to open the opening, and the sub-opening is inserted into the can. It is described that the contents are efficiently discharged from the main opening by the air that can flow freely.

Japanese Unexamined Patent Publication No. 2007-22541 Japanese Unexamined Patent Publication No. 2008-168923

As described in Patent Document 1 or Patent Document 2, by providing the second opening together with the first opening for pouring the contents to the outside, the contents can be poured out from the opening of the first opening. Since air can flow in stably from the opening of the second opening, it is possible to prevent the contents to be injected and the air to flow in from intersecting with each other in the first opening to cause pulsation. The contents can be smoothly poured out from one opening. Further, since the second score that defines the second opening is continuously formed on the first score that defines the first opening, the first score is operated by operating one tab during the can opening operation. The opening and the second opening can be opened.

However, when the second score is formed continuously with the first score, the total length of the score becomes long. Therefore, in order to open the second opening in addition to the first opening, it is large during the can opening operation. Breaking force is required, and the opening property (can opening property) deteriorates. On the other hand, in order to maintain good openness of the opening, it is conceivable to reduce (thin) the residual thickness of the score to suppress an increase in breaking force during the can opening operation. In this case, When the internal pressure inside the can rises and buckling occurs, the score may be broken (score out) or the hinge of the opening may be broken. Further, if the score is broken, the contents inside the can may be leaked.

The present invention has been made in view of such circumstances, and it is possible to prevent breakage of the score and leakage of the contents, and it is possible to easily open the opening at the time of opening the can to improve the openness. An object of the present invention is to provide a can lid having good pouring property, which allows the contents to be poured out quickly and smoothly.

The can lid of the present invention includes a can lid main body and a tab attached to the can lid main body, and the can lid main body has an opening defined by a first score and a second score, and the can lid. A rivet is formed so as to project from the central portion of the upper surface of the main body to which the tab is attached, and the opening is defined by the first score, and from the peripheral portion of the rivet to the peripheral edge of the upper surface of the can lid main body. It has an overhanging first opening and a second opening defined by the second score and overhanging a region opposite to the first opening with the rivet in between, and has an upper surface of the can lid main body. In the plan view of, the line passing through the center of the rivet and passing through the position farthest from the rivet of the first score is defined as the Y axis, and the line passing through the center of the rivet and orthogonal to the Y axis is defined as the X axis. In addition, the end of the second score is extended to a region opposite to the first score across the X-axis, and at least the extension portion following the connection end with the first score is the end. The residual thickness transition portion, which is formed in a linear or curved shape extending so that the distance from the center of the rivet becomes longer toward the direction of the score, and the connecting end of each of these scores is larger than that of the other portion of each of the scores. The residual thickness portion is formed thick, and the thickness of the residual thickness portion of the residual thickness transition portion is formed larger than the thickness of the residual thickness portion of the intermediate portion of the first score within a range of 15% or more and 40% or less. The thickness of the residual thickness portion of the stretched portion of the second score is formed to be larger than the thickness of the residual thickness portion of the intermediate portion of the first score .

The can lid of the present invention has a configuration in which the opening has a first opening overhanging the upper peripheral edge of the can lid main body and a second opening overhanging a region opposite to the first opening with a rivet in between. Further, the end of the second score that defines the second opening is extended to the region opposite to the first score across the X-axis, so that the contents are poured out from the opening of the first opening. At that time, since air can flow in stably from the opening of the second opening, the occurrence of pulsation can be prevented, and the contents can be quickly and smoothly poured out from the opening of the first opening.
In this case, after opening the first opening (after the first operation), the second opening rotates the tab around the rivet in the extending direction of the second score in the state where the tab is raised (the second operation is performed). ) Therefore, it can be easily opened.

As described above, in the can lid of the present invention, the first operation for raising the rear end portion of the tab and the second operation for rotating the tab around the rivet are combined to form the first opening and the second opening. In the second operation, the tab is rotated around the rivet to press the second opening and act to tear the second score, so that a relatively large force is applied to the second score. Can be easily broken by acting on.

Then, since the extended portion of the second score is formed in a straight line or a curved shape extending so as to gradually separate from the center of the rivet toward the end, the second score is smoothly broken at the time of opening, and at the end portion. The break of the score can be surely stopped. When this second score is formed in an arc shape centered on a rivet, when the tab is raised and rotated, the score will break beyond the end unless the operation to stop the break of the score is intentionally stopped. However, since the stretched part of the second score is formed in a straight line or curved shape that gradually separates from the center of the rivet toward the end, the opening does not stop in the middle and resistance to breakage. The force gradually increases and can be reliably stopped at the end. Since the momentum of breakage gradually weakens, the risk of inadvertently touching the fracture surface with the finger due to the momentum at breakage is also reduced.

In the can lid of the present invention, the panel deboss formed in a concave shape is provided on the upper surface of the can lid main body, and the tab and the score are provided in the area surrounded by the peripheral edge of the panel deboss. The distance between the peripheral edge of the panel deboss and the score is preferably 1.5 mm or more.

In the can lid of the present invention, it is preferable that the end of the second score is arranged within the range of the back area of the tab. In this case, further, the tab is formed with a tab hole penetrating in the thickness direction on the side opposite to the first opening via the rivet, and the end of the second score is exposed to the tab hole. It is often easy to confirm the end of the score from the outside, and the opening operation of the second score can be surely performed.

According to the present invention, in a can lid having an opening having a first opening and a second opening, the pressure resistance strength does not decrease even if the score is stretched, and the score is broken or the contents are leaked. Occurrence can be prevented, the opening can be smoothly opened to maintain good can openability, and the contents can be poured out quickly and smoothly. In this case, during the opening operation of the second opening, the opening speed gradually decreases to the extent that the breaking of the score does not stop in the middle, and the risk of the finger touching the fracture surface with the momentum at the time of opening is reduced.

It is a top view of the can lid of 1st Embodiment of this invention. It is sectional drawing on the Y axis of the can lid shown in FIG. It is a top view of the main part of the score part of the can lid shown in FIG. It is a cross-sectional view of the middle part of the 1st score. It is an enlarged plan view of the shortest distance part between a score and a peripheral part of a panel deboss. It is a cross-sectional view of the peripheral portion of the panel deboss and the score in the shortest distance portion of FIG. It is a top view of the can lid explaining the opening method of the opening, (a) is the state which opened the 1st opening, (b) is the state which opened the 2nd opening, (c) is the opening of the opening. It shows the state where the tab is returned to the original position later. It is a top view of the can lid of the 2nd Embodiment of this invention. It is a top view of the main part of the score part of the can lid shown in FIG.

Hereinafter, embodiments of the can lid according to the present invention will be described with reference to the drawings.
The can lid 101 of the first embodiment is, for example, a so-called stayion tab type can lid used for cans for beverages and the like, and as shown in FIG. 1, the can lid main body 1A and the can lid main body 1A. It is composed of a tab 2 attached to the. The can lid body 1A and the tab 2 are each made of an aluminum alloy.

As shown in FIG. 1, the can lid main body 1A includes a substantially disk-shaped panel portion 10 and an annular counter sink portion 11 provided so as to be convex downward along the outer peripheral portion of the panel portion 10. It has. A concavely formed panel deboss 12 is provided on the upper surface of the panel portion 10, and a rivet formed on the bottom surface of the panel deboss 12 and protruding from the central portion of the panel portion 10 (can lid body 1A). 13 is formed, and the tab 2 is attached to the rivet 13. Further, an opening 8 defined by the score 3 is formed on the bottom surface of the panel deboss 12, and a finger hook recess 14 is provided on the side opposite to the opening 8 (upper side in FIG. 1), and these rivets are provided. A convex portion 15 called a dimple is formed between the 13 and the finger rest recess 14. Further, the tab 2 and the score 3 are provided in the area surrounded by the peripheral edge portion 12a of the panel deboss 12.

The rivet 13 is integrally formed with the panel portion 10 by performing a coining process for imprinting the upper surface of the panel portion 10 in a ring shape and projecting the central portion of the panel portion 10 upward.
Further, the finger hook recess 14 is formed so as to be along the rear end portion (pulling portion 22) of the tab 2 and in the vicinity of the lower portion thereof, a part of the bottom surface of the panel deboss 12 is further recessed. The opening person can put his / her finger under the rear end portion of the tab 2 from the finger hook recess 14 so that he / she can easily pull up by putting his / her finger on the rear end portion.

The score 3 defines the opening 8, and by pressing the opening 8 with the tab 2 to break the score 3, the opening 8 is pushed into the can and the drinking spout is opened. An auxiliary score 9 formed in parallel adjacent to the score 3 is formed inside the score 3, and the score 3 and the auxiliary score 9 are connected at the start end 31 and the end 39 of the score 3. Has been done. The auxiliary score 9 is formed shallower than the score 3, and is not broken by the pressing of the tab 2.

Then, as shown in FIG. 3, the score 3 has a configuration having a first score 4 and a second score 5A, and the opening 8 has a first opening 81 defined by the first score 4. , A second opening 82 defined by a second score 5A. Of these, the first opening 81 is formed so as to project from the peripheral portion of the rivet 13 to the upper peripheral edge portion of the can lid main body 1A, and the second opening 82 is opposite to the first opening 81 with the rivet 13 interposed therebetween. It is formed overhanging the area.

As shown in FIG. 3, the first score 4 includes a start end portion 31 formed around the peripheral portion of the rivet 13 and connected to the start end portion of the auxiliary score 9, and an arcuate concave arc portion 32 that surrounds the rivet 13 approximately half. The can lid body 1A has an arc-shaped intermediate portion 33 that is convex outward in the radial direction and a connection end portion 34 that is connected to the second score 5A, and is shown by hatching in the lower portion of FIG. As described above, the first opening 81 is defined. Further, the first opening 81 leaves a part of the first hinge portion C1 between the start end portion 31 of the first score and the connection end portion 34 (end point) as shown by a broken line in FIG. It is formed. The start end portion 31, the concave arc portion 32, the intermediate portion 33, and the connection end portion 34 constituting the first score 4 are loosely connected by sharing a tangent line at the end points where they are connected to each other.
The concave arc portion 32 is formed in a ring-shaped printing pressure portion crushed by coining around the rivet 13, and becomes an initial fracture portion when the opening 8 is pressed by the tab 2.

As shown in FIG. 3, the second score 5A extends from the connection end portion 37 continuous with the connection end portion 34 of the first score 4 to the region opposite to the rivet 13 continuously from the connection end portion 37. It is composed of an extension portion 38 and a termination portion 39 connected to the end portion of the auxiliary score 9. Further, as shown in FIG. 1, in the second score 5A, in the plan view of the upper surface of the can lid main body 1A (panel portion 10), the end of the second score 5A (score 3) is the first with the X axis in between. It extends to the area opposite the score 4 and is located within the range of the back area of the tab 2 (below the tab 2). The second score 5A is formed by leaving a part of the second hinge portion C2 between the center O1 of the rivet 13 and the end portion of the score 3 (the end portion 39 of the second score 5A) as shown by a broken line. Then, as shown by the hatching of the upper portion in FIG. 3, the second opening 82 continuous with the first opening 81 is defined.

The second hinge portion C2 is a portion that is bent when the second opening 82 is opened by the second operation of rotating the tab 2, and as shown in FIG. 3, the breaking arrival point of the end portion 39 and the center of the rivet 13 It is formed so as to connect with O1. Therefore, the position of the second hinge portion C2 slightly varies depending on how far the end portion 39 is cut.
On the other hand, the first hinge portion C1 is a portion that is bent when the first opening 81 is opened by the first operation, and as shown in FIG. 3, the breaking arrival point of the starting end portion 31 and the breaking reaching point of the connecting end portion 34. It is formed so as to connect with. Therefore, the position of the first hinge portion C1 slightly varies depending on how far the start end portion 31 and the connection end portion 34 are broken.

Further, as shown in FIGS. 1 and 3, the connecting end portion 34 of the first score 4 passes through the center O1 of the rivet 13 and is the most from the rivet 13 of the first score 4 in the plan view of the upper surface of the can lid main body 1A. When the line passing through a distant position (the point P1 at the outermost peripheral position of the can lid body 1A) is defined as the Y axis, and the line passing through the center O1 of the rivet 13 and orthogonal to the Y axis of the first score 4 is defined as the X axis. The score 3 is formed at a position including the point Q1 where the score 3 intersects the X axis. Although the point Q1 is the end point of the connection end portion 34 of the first score 4, the connection end portion 34 may be formed so as to extend to a position beyond this point Q1.
In the case of the present embodiment, the portion from the connection end portion 34 of the first score 4 to the connection end portion 37 of the second score 5A is formed with a thicker residual thickness portion than the other portions of these scores 4 and 5A. However, the thickness may be the same as the residual thickness portion of the intermediate portion 33 in front of the connection end portion 34. Further, the remaining thickness portion of the connection end portion 37 may be formed thicker than the connection end portion 34, or both may have the same thickness. In the present specification, the connection end portion 34 and the connection end portion 37 are collectively referred to as a residual thickness transition portion 6.

In the can lid 101 of the present embodiment, as shown in FIG. 3, two intersections P1 and P2 where the Y-axis and the first score 4 (first opening 81) intersect in a plan view of the can lid main body 1A. Assuming that the direction facing the intersection P2 at the tip of the first score 4 is 0 o'clock (the direction of the intersection P2) with reference to the intermediate position O2 of, the residual thickness transition portion 6 has a length L at a position of about 10:30. It is formed at 3 mm. The thickness of the residual thickness portion of the first score 4 is 0.085 mm to 0.100 mm at the position of the intermediate portion 33 from 3 o'clock to 10 o'clock, and the thickness of the residual thickness portion of the residual thickness transition portion 6 is 0. It is set to 100 mm to 0.125 mm, and the thickness of the residual thickness portion of the residual thickness transition portion 6 is within a range of 15% or more and 40% or less of the thickness of the residual thickness portion of the portion of the intermediate portion 33 from 3:00 to 10:00. It is set to be large. Further, the thickness of the residual thickness portion at the position (intersection point Q2) overlapping the first score 4 on the tip end side of the tab 2 is set to be larger than the thickness of the residual thickness portion before and after that.

Further, the thickness of the residual thickness portion of the stretched portion 38 of the second score 5A is set to be 0.100 mm to 0.110 mm, and the thickness of the residual thickness portion of the stretched portion 38 and the end portion 39 remains. It is formed smaller than the thickness transition portion 6, but is formed larger than the middle portion 33 between 3:00 and 10:00.

The connection end portion 37 of the second score 5A is loosely connected to the connection end portion 34 of the first score 4 by sharing a tangent line at the end points where they are connected to each other, and the connection end portion of the first score 4 is loosely connected. The area from the portion 34 to the end of the second score 5A is formed in a straight line or a curved arc with a large radius of curvature, and the connection end portion 37 and the extension portion 38 and the extension portion 38 and the end portion 39 of the second score 5A are formed. They are loosely connected by sharing a tangent line at the end points where they are connected to each other.
Specifically, in the embodiment shown in FIG. 1, a curve having a radius of curvature R1 of 50 mm or more, for example, 70 mm, is large between the connection end 34 of the first score 4 and the end 39 of the second score 5A. It is formed in a shape and can be said to be almost linear within that range. Further, when the rivet 13 is viewed in the center, the second score 5A extends from the extending portion 38 toward the end of the second score 5A so as to gradually separate from the center of the rivet 13, except for the connecting end portion 37 thereof. Is formed.

Further, in this can lid 101, the distance from the center O1 of the rivet 13 to the side end portion (point U1) in the width direction (X-axis direction) of the tab 2 is A, and the score is from the center O1 of the rivet 13 on the X-axis. When the distance to 3 (in this case, the residual thickness transition portion 6 and the connection point between the connection end portion 34 of the first score 4 and the connection end portion 37 of the second score 5A) is B, the distance A is It is formed smaller than the distance B, and the score 3 is arranged farther from the center O1 of the rivet 13 than the lateral end portion (point U1) of the tab 2 in the width direction.

In this case, the difference (BA) between the distance B and the distance A is preferably formed to be 3.0 mm or less. By setting the difference (BA) to 3.0 mm or less, the position of the score 3 is set to a position close to the point of action where the tab 2 and the opening 8 (the first opening 82 and the second opening 82) come into contact with each other. Since it can be arranged in, the breaking force of the score 3 (second score 5A) required at the time of opening the can can be made relatively small, and good openness can be ensured. When the difference (BA) is set to a size exceeding 3.0 mm, the position of the score 3 is far from the point of action where the tab 2 and the opening 8 come into contact with each other, so that a large breaking force is required during the can opening operation. And the openness becomes worse.
Further, the connection end portion 34 of the second score 5A is exposed to the outside of the tab 2, but the extension portion 38 and the end portion 39 are arranged below the tab 2 and are not visible from the outside.
On the other hand, the peripheral edge of the panel debossing 12 is formed so as to surround the first score 4 at a substantially constant interval on the outside thereof, but is opposite to the first score 4 from the vicinity where the X-axis passes. On the side, it is formed so as to surround the outside of the tab 2. Therefore, either the connecting end portion 37 of the second score 5A or the first half portion of the extending portion 38 is arranged closest to the peripheral edge portion of the panel deboss 12.

As shown in FIG. 4 in FIG. 4, the cross section of the intermediate portion 33 of the first score 4 is formed in a symmetrical inverted trapezoidal shape in which the opening width becomes narrower toward the bottom of the blade, and the scores 3 are formed on both side surfaces. The opening angle 2α is formed, for example, at 50 °. On the other hand, the score 3 (the connection end 37 in the example shown in FIG. 5) located closest to the peripheral edge of the panel deboss 12 is not symmetrical in cross section as shown in FIG. The inclination angle β of the side surface closer to the panel deboss 12 is formed to be larger than the inclination angle α of the side surface on the opposite side. The difference in angle (β-α) is set to 1 ° to 3 °.
The shortest distance between the peripheral edge of the panel deboss 12 and the score 3 is from the intersection of the peripheral surface and the bottom surface of the panel deboss 12 to the intersection of the side surface and the bottom surface of the score 3 on the peripheral edge side of the panel deboss 12. The distance L is set to 1.5 mm or more. If the distance is increased, the tab 2 is approached, and the portion of the shortest distance L is close to the point Q1 described above. Therefore, the upper limit of the distance is set on the peripheral edge of the tab 2 so that the tab 2 can be opened. It is set appropriately in relation to the position.

The tab 2 is attached to the rivet 13 as described above, and overlaps the one end of the tab 2 above the first opening 81 when the longitudinal direction of the tab 2 is arranged parallel to the Y axis of the can lid body 1A. A pressing portion 21 is formed, and a pulling portion 22 is formed at the other end portion arranged on the opposite side of the rivet 13 (X-axis).
As shown in FIGS. 1 and 3, the pressing portion 21 is formed in an arc shape, and a tongue portion 24 is formed by a U-shaped slot 23 between the pressing portion 21 and the pulling portion 22 to form a tongue. A rivet hole (not shown) is formed in the portion 24. Then, the tab 2 is attached to the can lid main body 1A in a state where the rivet 13 is inserted into the rivet hole and the lower surface of the tongue portion 24 is in contact with the upper surface of the panel deboss 12 (can lid main body 1A). Further, a tab hole portion 25 penetrating in the thickness direction of the tab 2 is formed in the pulling portion 22 of the tab 2.

Next, a method of opening the opening 8 in the can lid 101 configured as described above will be described.
(First operation)
First, in a state where the pressing portion 21 of the tab 2 is overlapped with the first opening 81 (state in FIG. 1), the first operation of pulling up the pulling portion 22 of the tab 2 is performed. When the pulling portion 22 of the tab 2 is pulled up, the pressing portion 21 of the tab 2 comes into contact with the upper surface of the first opening 81, and the pressing portion 21 serves as a fulcrum to lift the rivet 13 upward. At this time, the portion of the concave arc portion 32 of the first score 4 on the first opening 81 side is in a state of being pressed by the tab 2, and the portion of the concave arc portion 32 on the rivet 13 side is lifted upward. Shear force acts on the concave arc portion 32 to break (pop operation). Since the first opening 81 is reinforced by the inner bead 41 and the deformation is suppressed, a shearing force can be reliably applied to the concave arc portion 32, and the concave arc portion 32 can be smoothly broken.

Then, when the pulling portion 22 of the tab 2 is further lifted, the rivet 13 becomes a fulcrum, the pressing portion 21 of the tab 2 becomes an action point, and the first opening 81 surrounded by the first score 4 becomes the inside of the can by the tab 2. The first score 4 is sequentially broken while being pushed into the first opening 81 so as to orbit the first opening 81 (tier operation). Then, when the fracture of the score 3 reaches the residual thickness transition portion 6, the brake is surely applied in the residual thickness transition portion 6 in which the thickness of the residual thickness portion is formed larger than that of the intermediate portion 33, and the fracture progress of the score 3 progresses. It will be stopped. Next, stress is concentrated at the fracture stop point of the residual thickness transition portion 6, and the first hinge portion C1 of the connecting portion between the residual thickness transition portion 6 and the start end portion 31 is bent. Then, when the first opening 81 is pushed into the can, the first opening 81o opens as shown in FIG. 7A.

(Second operation)
After that, as shown by an arrow T in FIG. 7A, the second tab around the rivet 13 is maintained in a state where the tab 2 is raised (a state in which the tab 2 is raised substantially perpendicular to the upper surface of the can lid body 1A). By performing the second operation of rotating and twisting the score 5A in the extending direction (clockwise T direction), the second opening 82 between the second score 5A and the rivet 13 is pressed by the side end portion of the tab 2. To do. At this time, the distance A from the center O1 of the rivet 13 to the side end portion (point U1) of the tab 2 is formed to be smaller than the distance B from the center O1 of the rivet 13 to the score 3 (here, the first score 4). Therefore, even if the tab 2 is rotated with the tab 2 raised, it is possible to prevent the tab 2 from coming into contact with the broken score end face. As the tab 2 rotates, as shown in FIG. 7B, the second opening 82 is pushed down into the can, the second score 5A is torn, and the second score 5A is terminated from the extending portion 38. Breaking progresses sequentially toward the portion 39, and the second hinge portion C2 is bent. Then, the second opening 82 is pushed into the can, and the second opening 82o opens in the region opposite to the first opening 81o with the rivet 13 interposed therebetween.

Further, by the second operation, the first opening 81 connected to the second opening 82 via the first hinge portion C1 is further pushed into the can, so that the first opening 81o of the first opening 81 can be used. The area of the part facing the outside becomes smaller. In this way, after the first score 4 is broken by the first operation, the second score 5A is continuously broken by the second operation, so that the side opposite to the first opening 81 sandwiching the X-axis (rivet 13) is opposite. A second opening 82 is opened in the region following the first opening 81, and an opening 80o having an opening area S1 of the first opening 81 and an opening area S2 of the second opening 82 is formed.

Then, after breaking the second score 5A to open the opening 8, the tab 2 is returned to the original position as shown in FIG. 7 (c).
When the first score 4 is broken to open the first opening 81 (first opening 81o) and then the tab 2 is tilted to the original position without being rotated to return to the state before opening. The state in which only the first opening 81 is opened can be maintained without opening the second opening 82. As described above, in the can lid 101, since the residual thickness transition portion 6 is present, the opening of the opening 8 can be stopped once before the complete opening (opening 80o), and the normal opening (the second) is performed by the operation of the tab 2. 2 An opening only in an area that is opened in a normal can lid without a score of 5A, and an opening corresponding to the first opening 81o in the present embodiment) and a complete opening (opening 80o opened to the second opening 82o). Consumers can choose.

As described above, in the can lid 101 of the present embodiment, the openings 8 (first openings 81 and second) defined by the first score 4 and the second score 5A on the upper surface of the can lid main body 1A. The opening 82) is connected by the second hinge portion C2, and the second score 5A is continuously broken by the second operation of rotating the tab 2 around the rivet 13 after the first operation. When this is done, the first opening 81 is pushed into the can together with the second opening 82, so that the opening 8 composed of the first opening 81 and the second opening 82 opens in the can lid main body 1A. However, an opening 80o having a large opening area is formed. Then, the end of the second score 5A that defines the second opening 82 is extended to the region opposite to the first score 4 with the rivet 13 (X-axis) interposed therebetween, so that the first opening 81 is the first. When the contents are poured out from the 1 opening 81o, air can stably flow in from the 2nd opening 82o of the 2nd opening 82, so that the occurrence of pulsation can be prevented and the contents can be discharged to the outside from the 1st opening 81o. Can be poured out quickly and smoothly.

Further, in the can lid 101, the opening 8 is composed of the first opening 81 and the second opening 82, and the first hinge portion C1 and the second hinge portion C2 are respectively bent in order to open the opening 8. Since the structure is such that 80o is opened, the first opening 81 opened first can be deeply folded inside the can together with the opening of the second opening 82. As a result, the portion where the opening 8 covers the first opening 81o of the first opening 81 and faces the outside from the opening can be reduced. Therefore, when the can is tilted and the contents flow out from the first opening 81o of the first opening 81 toward the outside, it is possible to avoid the opening 8 becoming an obstacle and causing pulsation, and the first opening The contents can be smoothly poured out from the first opening 81o of 81.

Further, in the can lid 101, the first operation for causing the tab 2 and the second operation for rotating the tab 2 around the rivet 13 are combined to open the first opening 81 and the second opening 82. In the first operation, the propagation of the fracture of the score 3 is surely stopped at the residual thickness transition portion 6, and the first opening is bent between the first opening 81 and the second opening 82. Since the 81 is opened, the breaking force of the score 3 (first score 4) in the first operation can be kept low.

On the other hand, the second operation is formed shallower than the intermediate portion 33 because the tab 2 is rotated around the rivet 13 to press the second opening 82 and act to tear the second score 5A. Even if the residual thickness transition portion 6 or the second score 5A is formed, that is, even if the residual thickness portion is formed to be thicker than the intermediate portion 33, it can be easily broken. Further, by forming the thickness of the residual thickness portion in the portion after the stretched portion 38 of the second score 5A smaller than the thickness of the residual thickness portion of the residual thickness transition portion 6, the breaking force of the portion after the stretched portion 38 is compared. The target can be kept low, and the openability of the second opening 82 can be improved.
In this case, the extension portion 38 and the end portion 39 of the second score 5A are formed in a straight line or a curved shape so as to gradually separate from the center of the rivet 13 toward the end, so that when the second score 5A is broken. While gradually increasing the resistance of the rivet without suddenly increasing it on the way, it is possible to smoothly break the rivet and surely stop the breaking of the score at the terminal portion 39 thereof.
In this way, when the portion of the second score 5A after the stretched portion 38 is formed deeper than the residual thickness transition portion 6 and shallower than the intermediate portion 33, a second score 5A is provided to score. Despite the long overall length of No. 3, it is possible to suppress a decrease in the pressure resistance of the can lid 101. Therefore, even when the internal pressure inside the can rises and buckling occurs, it is possible to prevent breakage of the score 3 and leakage of the contents.

In the can lid 101 of the first embodiment, the second score 5A was formed relatively short, and the end portion 39 was formed by a straight line or a gently curved line continuous with the extension portion 38, but the extension portion 38 was formed. And the shape of the end portion 39 is not limited to this. For example, when the total length of the second score 5B is formed longer as in the can lid 102 (can lid main body 1B) of the second embodiment shown in FIGS. 8 and 9, the stretched portion 38 of the second score 5B is formed. The back surface of the tab 2 is formed by extending the end portion 39 to a position in front of the end portion 39 of the second score 5A in the first embodiment, for example, with a radius of curvature R1 and bending the end portion 39 with a radius of curvature R2 smaller than that of the extension portion 38. It may be formed within the range of the region. Specifically, the radius of curvature R2 of the terminal portion 39 is reduced to about 6 mm to 10 mm, and the terminal portion 39 is formed in the region between the rivet 13 of the panel portion 10 and the finger hook recess 14 as much as possible. It is preferable to form it close to the rivet 13.
The tab 2 is the same as that of the first embodiment, and in FIGS. 8 and 9, the elements common to the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

Similarly to the can lid 101 of the first embodiment, the can lid 102 of the second embodiment also has a residual thickness transition portion 6 having a length of 1.5 mm or more and 5.0 mm or less, and the residual thickness transition portion 6 has a length of 1.5 mm or more and 5.0 mm or less. By forming the thickness of the residual thickness portion larger in the range of 15% or more and 40% or less than the thickness of the residual thickness portion of the intermediate portion 33, the first score 4 is broken by the first operation and the first opening 81. The score 3 can be reliably stopped at the residual thickness transition portion 6 in which the depth of the score 3 is shallower than that of the intermediate portion 33, that is, the thickness of the residual thickness portion is large, and the breakage of the score 3 can be reliably stopped. The first opening 81 can be opened by surely bending between the 81 and the second opening 82.
Then, after opening the first opening 81 (after the first operation), the second opening 82 rotates the tab 2 around the rivet 13 in the stretching direction of the second score 5B with the tab 2 raised (after the first operation). By performing the second operation), the opening can be easily performed.

In order to increase the opening area S2 of the second opening 82 as in the can lid 102 of the second embodiment, it is necessary to increase the total length of the second score 5B, but the total length of the second score 5B is As the length increases and the position of the end portion 39 becomes farther from the center O1 of the rivet 13, the distance between the position of the second score 5B and the pressing portion of the second opening 82 by the tab 2 becomes longer (farther). The breaking force required to break the 2 score 5B tends to increase. In this respect, the tab 2 is rotated by forming the end portion 39 of the second score 5B by bending it with a small radius of curvature R2 without being significantly separated from the rivet 13, as in the can lid 102 of the second embodiment. At this time, it can be formed without significantly increasing the distance between the position of the second score 5B and the pressing portion of the second opening 82 by the tab 2. Therefore, the breaking force of the second score 5B required at the time of opening the can of the second score 5B is not increased, and it is possible to avoid putting a heavy burden on the finger when rotating the tab 2, so that the opening area can be avoided. The large second opening 82 of S2 can be reliably opened.
In this case, the position of the end of the end portion 39 and the radius of curvature R2 of the end portion 39 are substantially set by appropriately setting according to the resistance force at break that increases with the increase in the distance from the rivet 13. The linear stretched portion 38 (with a large radius of curvature R1) breaks smoothly, and the end portion 39 with a small radius of curvature R2 thereafter gradually increases in resistance at the time of breaking, and breaks reliably at the end. It can be stopped.

Further, if the end portion 39 of the second score 5B is formed close to the peripheral edge portion of the panel portion 10, the pressure resistance strength of the can lid 102 is likely to decrease. Therefore, by keeping the forming position of the end portion 39 in the peripheral region of the rivet 13, it is possible to avoid a decrease in the pressure resistance of the can lid 102.
Further, as in the can lid 102 of the second embodiment, the formation range of the second score 5B is contained within the range of the back area of the tab 2, so that the total length of the second score 5B is lengthened and the second opening is opened. Even when the opening area S2 of the portion 82 is formed to be large, the opening portion of the second opening 82 can be hidden behind the tab 2, so that it is possible to avoid spoiling the appearance.

Hereinafter, Examples and Comparative Examples performed for confirming the effect of the present invention will be described.
Using an aluminum plate having a plate thickness of 0.280 mm, can lids (can lid bodies) having a diameter of 200 to 206 under the conditions shown in Table 1 below were prepared, and the openness of these can lids was evaluated as follows.

(Aperture performance)
We asked 20 panelists to open the sample and collected comments on openness. In each sample, the score could be broken to the end, but the one that did not feel any discomfort during the opening operation was marked with "○", and the one that felt some discomfort was marked with "Δ".
The results are shown in Table 1.

Regarding sample 4, comments such as "the cut end and the finger are likely to touch" and "opening too vigorously" were obtained from five panelists in Table 1, so the evaluation was given as Δ. For Samples 1 to 3, the score could be broken without feeling any discomfort until the end.
Next, with respect to the can lid of sample 2, the pressure resistance performance was evaluated by changing the shortest distance L to the peripheral edge of the panel deboss and the angle β of the side surface of the score (see FIG. 6). The angle α of the other side of the score was set to 25 °.
(Withstand voltage performance)
The pressure resistance performance is evaluated by wrapping each can lid around an empty can body, cutting the can body at an intermediate position, and then using a pressure resistance test device manufactured by Floris Enterprise Co., Ltd. for 100 kPa / 30 seconds. Water pressure was applied at the boosting speed, and a pressure resistance test was performed to measure the pressure when a buckling phenomenon called cornering, in which a part of the can lid partially protrudes, or score cracking occurred. In this case, in a rigorous test in which the pressure is increased to 700 kPa, which is higher than the withstand voltage required in normal usage, those without buckling or score cracking are marked with "○", and those with buckling or score cracking are marked with "○". × ”was evaluated.
The results are shown in Table 2.

Since it was a rigorous test, the pressure resistance of the sample 14 having a short shortest distance L of 0.9 mm was evaluated as "x", but it has a pressure resistance that does not cause any particular problem in normal use.

The present invention is not limited to the configuration of the above embodiment, and various changes can be made to the detailed configuration without departing from the spirit of the present invention.
In the second embodiment, the extension portion of the second score is formed substantially linearly, and the radius of curvature is formed small at the end portion. However, in the present invention, the portion excluding the end portion of the second score (connection end portion). And the stretched portion), it may be formed in a straight line or a curved shape having a large radius of curvature, and the stretched portion following the connecting end portion may extend so as to gradually separate from the center of the rivet toward the end.

1A, 1B Can lid body 2 Tab 3 Score 4 1st score 5A, 5B 2nd score 6 Residual thickness transition part 8 Opening 9 Auxiliary score 10 Panel part 11 Counter sink part 12 Panel deboss 13 Rivet 14 Finger hook concave part 15 Convex part 21 Pressing part 22 Pulling part 23 Slot 24 Tongue part 25 Tab hole part 31 Starting end part 32 Concave arc part 33 Intermediate part 34 Connecting end part 37 Connecting end part 38 Extension part 39 Ending part 41, 42 Inner bead 80o Opening 81 First opening 81o 1st opening 82 2nd opening 82o 2nd opening 101,102 Can lid C1 1st hinge part C2 2nd hinge part

Claims (4)

It is provided with a can lid body and a tab attached to the can lid body.
The can lid main body is formed with an opening defined by the first score and the second score, and a rivet projecting from the center of the upper surface of the can lid main body to which the tab is attached.
The opening is
A first opening defined by the first score and projecting from the peripheral portion of the rivet to the upper peripheral edge portion of the can lid main body, and
It has a second opening defined by the second score and overhanging a region opposite to the first opening with the rivet in between.
In a plan view of the upper surface of the can lid body,
When the line passing through the center of the rivet and passing through the position farthest from the rivet of the first score is defined as the Y axis, and the line passing through the center of the rivet and orthogonal to the Y axis is defined as the X axis.
The end of the second score is extended to a region opposite to the first score with the X-axis in between, and at least the extension portion following the connection end with the first score is directed toward the end. Therefore, it is formed in a straight line or a curved line extending so as to increase the distance from the center of the rivet .
The residual thickness transition portion consisting of the connecting ends of each of these scores is formed to have a thicker residual thickness portion than the other portions of the respective scores, and the thickness of the residual thickness portion of the residual thickness transition portion is the thickness of the first score. It is formed larger than the thickness of the residual thickness portion of the intermediate portion within a range of 15% or more and 40% or less, and the thickness of the residual thickness portion of the stretched portion of the second score is the residual thickness of the intermediate portion of the first score. A can lid characterized in that it is formed larger than the thickness of the portion. A concavely formed panel deboss is provided on the upper surface of the can lid main body, and the tab and the score are provided in an area surrounded by the peripheral edge of the panel deboss, and the peripheral edge of the panel deboss and the score are provided. The can lid according to claim 1, wherein the distance from the can lid is 1.5 mm or more. The can lid according to claim 1 or 2, wherein the end of the second score is arranged within the range of the back area of the tab. The tab is characterized in that a tab hole is formed through the rivet on the side opposite to the first opening in the thickness direction, and the end of the second score is exposed to the tab hole. The can lid according to claim 3.

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