JP5514664B2 - 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 and Patent Document 2, a steion tab type that can open a drinking mouth with a tab attached to a can lid body is known. This can lid has a score that defines an opening piece (drinking mouth) on the upper surface of the can lid body, a rivet that is arranged at the center of the can lid body, and one end portion that is supported by the rivet and overlaps the opening piece. And a tab that is disposed on the bottom, and is secured to the open end of the can body by being wound around the open end of the bottomed cylinder filled with the contents to form a so-called beverage can. In this beverage can, the other end portion of the tab opposite to the opening piece side is pulled up so that one end portion on the opening piece side is pressed and immersed in the opening piece to break the score and open the opening piece. .
In this case, the score has a double structure including a main score that is broken by a tab to form an opening piece, and an auxiliary score provided along the inside of the main score. The auxiliary score is provided to prevent the occurrence of defects such as cracks in the remaining thickness part while controlling the flow of material from the main score during processing to form the main score at an appropriate depth, It is shallower than the main score and is not broken by pressing of the tab.

By the way, in recent years, there is an increasing demand for improving the pouring property of contents. As a means for improving the pouring property, for example, the circumference of the main score is lengthened to increase the opening area of the opening piece.
However, if the opening area of the opening piece is increased, a large breaking force is required during the opening operation. Thus, in order to reduce the breaking force during the can opening operation, it is conceivable to form a thin remaining portion of the main score. However, the main score may be broken carelessly due to dropping or vibration.

  Further, in Patent Document 2, a proposal for reliably breaking a main score having a long circumference to the end is made. Make the remaining thickness of the terminal part of the auxiliary score adjacent to the terminal part of the main score thicker than the remaining thickness of the main body part up to the front of the terminal part by a predetermined length, increase the rigidity of the terminal part of the auxiliary score, and use the tab The pressing force is efficiently transmitted to the end portion of the main score, and is broken to the end portion of the main score. However, the reduction of the opening force during the opening operation has not been improved and was not sufficient.

Japanese Patent No. 3468548 JP 2006-56550 A

  The present invention has been made in view of such circumstances, and a can lid that can be opened with a relatively small force and that can prevent inadvertent breakage of the score due to dropping or vibration. provide.

  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 A can lid that breaks the main score and opens the opening piece, the tip of the opening piece being disposed at the outermost peripheral position of the can lid body of the main score, and the center of the can lid body If the direction opposite to the opening piece tip is 0 o'clock with reference to the middle position of the two intersections of the line connecting the main score and the main score, the remaining thick part of the auxiliary score and the remaining thick part of the main score The remaining thickness difference is the local area including the above 0:00 Characterized in that it is larger than the portion.

  Since the residual thickness difference between the main score and the auxiliary score is set large in the local area including 0 o'clock, which is the initial fracture portion of the opening piece, distortion occurs in the remaining thickness portion of the main score in the range when processing the main score Can be generated efficiently, and the breaking force (pop value) at the initial stage of opening the can can be reduced. In other parts, the remaining thickness difference between the main score and the auxiliary score is set as before, for example, the remaining thickness difference is set small between 3 and 9 o'clock, so that it breaks carelessly due to dropping or vibration. Without opening, it can be opened with normal force.

In the can lid of the present invention, the local region including the 0:00 is preferably an arc-shaped portion at least along the rivet.
In this case, by setting a large residual thickness difference between the main score and the auxiliary score around the rivet, distortion can be efficiently generated in the residual thickness portion of the main score near the contact portion between the tab and the opening piece. It is possible to reliably reduce the breaking force at the initial stage of opening the can.

Furthermore, in the can lid of the present invention, the remaining thickness difference between the main score and the auxiliary score in the local area including the time of 0 is 0.065 to 0.075 mm, and the remaining thickness difference in the other portion is 0.046 to 0.056 mm.
By setting the residual thickness difference between the main score and the auxiliary score in this way, the breaking force at the initial stage of opening the can is reduced, and the can can be opened with a normal force without being accidentally broken by dropping or vibration. be able to.

  According to the present invention, it is possible to open the can with a relatively small force by reducing the score breaking force at the initial stage of opening of the can, and other parts are set as usual only by changing the residual thickness difference in the local region. Therefore, inadvertent breakage of the score due to dropping or vibration can be prevented.

It is a top view which shows the can lid of this embodiment. It is sectional drawing of the can lid shown in FIG. It is principal part sectional drawing explaining a main score and an auxiliary | assistant score. It is a figure explaining the relationship with the remaining thickness part of a main score and an auxiliary score. It is a graph which shows the relationship between a pop value and a score level | step difference.

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 pure aluminum or 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 curled portion 16 continuous with the shoulder portion 15.

  As shown in FIG. 1, a rivet 3 protruding on the center M of the panel portion 10 a (can lid main body 1) is formed on the upper surface of the panel portion 10 a, and 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 (on the left side of the rivet 3 in FIG. 1). A finger-hanging recess 6 is formed on the opposite side (the right side of the rivet 3 in FIG. 1), and a protrusion 7 called dimple is formed between the rivet 3 and the finger-holding recess 6. A concave panel deboss 10 b is formed so as to surround the opening piece 5, the finger-hanging concave portion 6, and the convex portion 7.

The tab 2 includes one end portion 21 that is disposed above the opening piece 5 and a lifting portion 22 that is formed on the opposite side across the rivet 3. A tab hole portion 23 that opens in the thickness direction is formed. 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 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.

  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.

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

As shown in FIGS. 1 and 4, the score portion 4 includes a start end portion 41, an arc-shaped portion 42 that is an arc-shaped initial fracture portion that substantially halves the rivet 3, a substantially elliptical intermediate portion 43, and a terminal end The opening 44 is formed by leaving a part of the connecting portion 45 to the panel portion 10 a between the start end portion 41 and the end end portion 44. The arc-shaped 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. 3, the auxiliary score 4 b is formed shallower than the adjacent main score 4 a and is not broken by the pressing of the tab 2.

Next, the relationship between the main score 4a and the remaining thickness portion of the auxiliary score 4b will be described with reference to FIG.
Of the main score 4a, a line connecting the tip of the opening piece 5 arranged at the outermost peripheral position of the can lid main body 1 (panel portion 10a) and the center M of the can lid main body 1 is a reference line L, and the reference line L and the main score L When the direction opposite to the tip (point B) of the opening piece 5 is set to 0 o'clock (the direction of point A shown in FIG. 4) with reference to the intermediate position O between the two intersections A and B where the score 4a intersects, the main score The remaining thickness portion of 4a is set to 0.10 to 0.13 mm in a local region including 0 o'clock, for example, the arc-shaped portion 42 that is an initial fracture portion, and 0.12 in the portion of the intermediate portion 43 from 1 o'clock to 2 o'clock. It is set to be 0.08 to 0.11 mm in a portion of ˜0.16 mm, 3 o'clock to 9 o'clock (C3 to C9). Further, the remaining thickness portion of the auxiliary score 4b is set larger by 0.065 to 0.075 mm in the arc-shaped portion 42 than the remaining thickness portion of the main score 4a, and 0.046 to 0.0. It is set to be larger by 056 mm, and is set so that the remaining thickness difference between the main score 4a and the auxiliary score 4b is the largest in the arc-shaped portion 42.

Since the remaining thickness portion of the main score 4a is a portion that breaks when the can is opened, it is preferable to make it as thin as possible to facilitate the opening of the can, but if it is too thin, it may be broken due to vibration during transportation. There is. Therefore, the remaining thickness portion of the main score 4a cannot be made thinner than necessary.
On the other hand, as described above, the auxiliary score 4b is for controlling the flow of material from the main score 4a when the main score 4a is formed. Without the auxiliary score 4b, the main score 4a is formed. The material flows to the left and right of the main score 4a, and a large distortion occurs in the remaining thickness portion immediately below the main score 4a, which is the boundary position on the left and right, causing cracks. For this reason, by forming the auxiliary score 4b and controlling the material flow from the main score 4a to be blocked by the auxiliary score 4b, the occurrence of cracks in the remaining thick portion of the main score 4a is prevented. Therefore, by forming the auxiliary score 4b, it is possible to prevent the occurrence of cracks while forming the main score 4a deep and facilitating the opening of the can.

  The effect of controlling the material flow by the auxiliary score 4b is that when the residual thickness difference between the auxiliary score 4b and the main score 4a is small, much of the material flow is restricted by the auxiliary score 4b. When the remaining thickness difference is large, the remaining thickness portion of the auxiliary score 4b is increased, so that the material from the main score 4a can easily flow. Therefore, the remaining thickness difference between the main score 4a and the auxiliary score 4b is set within a predetermined range. In the present embodiment, the remaining thickness difference of the arc-shaped portion 42 with the center at 0 o'clock is set to other values. It is set larger than the part. Therefore, when the main score 4a and the auxiliary score 4b are processed, distortion generated in the remaining thickness portion of the main score 4a of the arc-shaped portion 42 is increased, and the breaking force of the main score 4a in the portion is reduced.

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. Thereby, in a state where the opening piece 5 side of the arc-shaped portion 42 of the main score 4 a is pressed by the tab 2, the rivet 3 side of the arc-shaped portion 42 is lifted upward, and shear force acts on the arc-shaped portion 42. Break (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).
Among the series of opening operations, the tear operation is a continuous break after a part of the main score 4a is broken by the pop operation. Therefore, the main score 4a can be broken relatively easily. However, since the pop operation causes breakage as a starting point for opening the can, it is necessary to reliably break the arc-shaped portion 42.

  In the can lid 100 of the present embodiment, the breaking force of the main score 4a is reduced in the local region (arc-shaped portion 42) including 0:00 around the rivet 3, so the breaking force (pop value) at the initial stage of opening the can. Can be reduced. In addition, the remaining thickness of the main score 4a is increased in the portion from 1 o'clock to 2 o'clock and the portion from 3 o'clock to 9 o'clock is kept so that the main score 4a does not open vigorously by lowering the pop value Sets the remaining thickness of the main score 4a to be small so as not to cause inadvertent breakage due to dropping or vibration.

Next, with respect to the can lid configured as described above, various samples in which the residual thickness difference between the main score 4a and the auxiliary score 4b in the arc-shaped portion 42 of the score portion 4 is changed are prepared, and the breaking force at the initial stage of opening the can (Pop value) measurement and vibration leakage test were performed.
In the used samples a to g, the remaining thickness portion of the main score 4a of the arc-shaped portion 42 is fixed to 0.10 to 0.13 mm, which is the same as the can lid of the above-described embodiment, and the main score 4a in the arc-shaped portion 42 is fixed. It is produced by changing the depth of the auxiliary score 4b for each sample. The remaining thickness portions of the main score 4a and the auxiliary score 4b other than the arc-shaped portion 42 were set in the same manner as the can lid of the above-described embodiment.

  For the measurement of the pop value, as disclosed in Japanese Patent Application Laid-Open No. 2009-103621, a can lid fixing portion for fixing the can lid and an arm portion to which a claw for hooking on the pulling portion 22 of the tab 2 is fixed. A rotation motor that lifts the pulling portion 22 of the tab 2 by rotating the arm portion around the vicinity of the rivet 3, a torque measuring device that measures torque applied to the rotation motor, and a rotation angle of the arm portion. Using a device equipped with a rotary encoder, the torque was measured while forcibly pulling up the pulling portion 22 of the tab 2 and opening the opening piece 5 with the can lid fixed, and the pop value was calculated from this torque.

  In the vibration leakage test, using a three-way simultaneous vibration test apparatus manufactured by SHINKEN Co., Ltd., producing a beverage can filled with the contents using the above-described sample can lid, putting this beverage can into a 24 can carton, Two cartons with dummy beverage cans are placed on it, and a weight is placed on it. The weight is 51 kg, the vibration frequency is 10 Hz, the amplitude is 5 mm, the vibration direction is only in the vertical direction, 5 The occurrence of leakage was confirmed every minute, and the time when leakage occurred in any beverage can in the carton was evaluated. A product which did not leak for 30 minutes or more was regarded as a non-defective product.

The measurement result of the pop value of each sample is shown in the graph of FIG. The “score remaining thickness difference (mm)” on the horizontal axis of the graph of FIG. 5 indicates the remaining thickness difference between the main score 4 a and the auxiliary score 4 b in the arc-shaped portion 42.
As shown in FIG. 5, the samples a and b in which the difference in remaining thickness of the arc-shaped portion 42 is 0.046 mm and 0.056 mm have a remaining thickness difference of 0.046 to 0 over the entire score as in the case of the conventional can lid. In the samples c to g in which the difference in remaining thickness of the arc-shaped portion 42 is increased, the pop value is improved as the remaining score difference is increased. It was confirmed that
In these samples, in the vibration leak test, no leak occurred in 30 minutes, but when tested for 1 hour or more, only the sample g having the lowest pop value (residual thickness difference 0.085 mm), Some leakage was found. Therefore, it is most preferable to set the remaining score difference to 0.065 to 0.075 mm.

  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 hook recessed part 7 Convex part 10a Panel part 10b Panel deboss 11 Corner part 12 Annular recessed part 13 Countersink part 14 Chuck wall part 15 Shoulder portion 16 Curl portion 21 One end portion 22 Lifting portion 23 Tabhole portion 24 Tangue portion 41 Start end portion 42 Arc shape portion 43 Intermediate portion 44 Termination portion 45 Connection portion

Claims (3)

  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 A can lid for opening the opening piece, the main score of a line connecting the tip of the opening piece arranged at the outermost peripheral position of the can lid body and the center of the can lid body among the main scores If the direction opposite the tip of the opening piece is 0 o'clock, the remaining thickness difference between the remaining thickness portion of the auxiliary score and the remaining thickness portion of the main score is 0 Local area including time is larger than other parts Can lid, wherein it is set.   The can lid according to claim 1, wherein the local region including 0:00 is an arc-shaped portion at least along the rivet. The remaining thickness difference between the main score and the auxiliary score in the local area including 0 o'clock is 0.065 to 0.075 mm, and the remaining thickness difference of the other portion is 0.046 to 0.056 mm. The can lid according to claim 1, wherein the can lid is provided.

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