JP4681354B2 - Easy-to-open can lid - Google Patents

Description

  The present invention relates to a can lid that can prevent the central portion of the can lid from bulging and deforming due to an increase in the internal pressure of the beverage can.

  Conventionally, there are many steion tab type can lids which push down the opening piece partitioned by the score line by lifting the finger hook part of the tab fixed to the panel part of the can lid by a rivet in the lid of the beverage can. It is used. And such a can lid is manufactured as a canned beverage by winding and fixing to a can body filled with the contents.

When this type of canned beverage is used as a positive pressure can such as carbonated beverages with high internal pressure, the panel of the can lid bulges and deforms, and as a result, the score line may break during transportation Increases nature. In order to eliminate such inconvenience, for example, in the invention described in Patent Document 1, an annular groove portion is formed on the inner peripheral side of the peripheral portion of the panel portion, that is, the flange portion, and the inner peripheral portion of the annular groove portion. A concave portion is formed by coining on the inner surface of the side panel portion, and the rigidity of this portion is increased by work hardening by coining.
JP-A 64-45250

  However, in the structure described in Patent Document 1, since a recess is formed by compressing a part of the panel portion, there are many restrictions on the range in which the recess can be formed or the size of the recess, and the panel. The part itself remains flat. Therefore, in such a can lid, the effect of improving the rigidity of the outer peripheral portion of the panel portion is small, and when the content of the canned beverage is a carbonated beverage or the like, the inside of the can is at a positive pressure, and the central portion of the can lid is There is a possibility that the tab attached to the center of the can lid protrudes outward from the front end of the tightening portion of the beverage can. For this reason, the tab may come into contact with the carton case, and the score line may break due to vibration during transportation, or the score line may break due to inadvertent impact on the carton case. When the canned beverage after filling is conveyed upside down on the line, the canned beverage may become unstable.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a can lid that can prevent the central portion of the can lid from bulging and deforming in a beverage can having a positive can internal pressure. It is.

In order to achieve the above object, the invention of claim 1 is provided with a substantially disk-shaped panel portion, an annular groove portion arranged at the peripheral edge portion of the panel portion, and an outer peripheral edge portion of the annular groove portion. A flange portion for fixing the can body is integrally formed, and the panel portion includes an opening piece defined by a score line and a panel portion that can open the opening piece by pulling up one end side serving as a finger hook portion. In the easy opening can lid formed with a tab fixed in the center, an annular recess is formed along the annular groove near the peripheral edge of the panel portion and on the inner peripheral side of the annular groove. The recess has an outer inclined surface on the outer side in the radial direction of the can lid and an inner inclined surface on the inner side in the radial direction of the can lid, and opens in a substantially V shape on the upper surface side of the panel portion. The surface is a corner that connects the annular groove and the panel. Is substantially continuously provided, the annular groove has a inner wall surface continuously provided on the corner portion, the angle between the outer inclined surface of the inner wall surface and the annular recess is in the range of 45 ° to 80 ° this in It is characterized by.

According to a second aspect of the present invention, in the configuration of the first aspect, the outer inclined surface and the corner portion are continuously provided by a curved surface that protrudes toward the upper surface side of the panel portion. It is.

  According to the first aspect of the present invention, the outer inclined surface of the annular recess is substantially connected to the corner portion connecting the annular groove and the panel portion, so that the annular recess that is the peripheral portion of the annular groove and the panel portion. Since the angle formed between the outer inclined surface and the outer groove can be improved by bending the corner connecting the annular groove and the outer inclined surface of the annular recess, the internal pressure is applied to the can lid of the beverage can. Even if added, the angle formed by the annular groove and the outer inclined surface of the annular recess is difficult to open, and the bulging deformation of the central portion of the can lid can be suppressed.

  Further, since the annular recess has an outer inclined surface and an inner inclined surface, in addition to improving the strength by bending the corner portion connecting the annular groove portion and the outer inclined surface of the annular recess, the outer inclined surface and the inner inclined surface are provided. By improving the strength of the annular recess itself by bending with the inclined surface, the strength of the peripheral part of the panel part can be further improved, the bulging deformation of the central part of the can lid can be sufficiently suppressed, and the annular recess is formed. By doing so, since the flat area | region of a panel part becomes narrow, the bulging deformation | transformation of a can lid center part will be further suppressed.

Furthermore, by setting the angle formed by the inner wall surface of the annular groove and the outer inclined surface of the annular recess to be 45 ° to 80 °, the can lid performance such as partial thinning of the can lid plate thickness and deterioration of the inner surface quality can be achieved. Without causing a decrease, the bulging deformation of the central portion of the can lid can be reliably suppressed.

According to the invention of claim 2, since there is no flat portion in the panel portion between the outer inclined surface and the corner portion, the bending strength at this portion can be increased. Even if the internal pressure increases, the bulging deformation of the central portion of the can lid can be suppressed.

  An example of the easy-to-open can lid 1 according to the present invention is shown in FIG. 1, and a partial sectional view thereof is shown in FIG. The can lid 1 shown here is press-molded from a metal thin plate such as an aluminum alloy coated with a well-known synthetic resin, and includes a disk-shaped panel portion 2 and a peripheral portion of the panel portion 2. An annular groove portion (counter sink portion) 3 recessed downward of the can lid 1 and a flange portion 4 for fixing the can body extending upward from the outer peripheral edge portion of the annular groove portion 3 are integrally formed. The inner wall surface 5 and the peripheral edge portion of the panel portion 2 are connected almost directly by a corner portion 6 having a circular arc section. Further, the panel portion 2 is formed with a rivet portion 7 for fixing tabs at substantially the center thereof, and an opening piece 9 defined by a score line 8 extending from the vicinity of the rivet portion 7 to the vicinity of the outer peripheral portion of the panel portion 2. Is formed.

  A tab 10 for opening operation is fixed to the rivet portion 7, and one end portion of the tab 10 is a push-down portion 11, which is located above the opening piece 9 and is a finger hook which is the other end portion of the tab 10. The score line 8 can be broken and opened by lifting the portion 12. Further, a finger hanging recess 13 that is recessed inward of the can lid 1 is formed in the panel portion 2 in the vicinity of the finger hanging portion 12 of the tab 10, and the panel portion 2 positioned below the tab 10 has an inner surface of the tab 10. A rotation-preventing protrusion 14 that fits into a concave portion (not shown) on the side is formed.

  Then, on the inner periphery side of the annular groove portion 3 and on the entire periphery of the peripheral edge portion of the panel portion 2, the panel portion side end of the corner portion 6 connecting the inner wall surface 5 of the annular groove portion 3 and the peripheral edge portion of the panel portion 2. An annular recess 15 that is recessed toward the inner surface of the can lid 1 is formed.

  The annular recess 15 includes an outer inclined surface 16 that is inclined inward and downward in the radial direction of the can lid 1 from the corner portion 6, and a narrow annular bottom surface 17 that is connected to the lower end of the outer inclined surface 16 and is substantially horizontal. The inner lid surface 18 is inclined from the bottom surface 17 inward in the radial direction of the can lid 1 and upward. In other words, the annular recess 15 is formed as a substantially V-shaped annular groove opened on the upper surface (outer surface) side of the panel portion 2.

  Further, the inner wall surface 5 of the annular groove portion 3 connected to the panel portion 2 and the outer inclined surface 16 of the annular recess portion 15 are interposed by a substantially flat portion (or a flat surface) by the corner portion 6 having an arcuate cross section. Therefore, the angle formed by the inner wall surface 5 of the annular groove portion 3 and the outer inclined surface 16 of the annular recess portion 15 is continuously smaller than 90 ° through a curved surface that is convex on the upper surface side of the panel portion 2. The angle is preferably 45 ° to 80 °. That is, the corner portion 6 is formed at an acute angle, and the annular recess 15 for making the corner portion 6 an acute angle is formed by curving the peripheral portion of the panel portion 2 in the plate thickness direction. Is designed to function as a so-called reinforcing bead.

  In addition, the upper end surface of the corner portion 6 connected to the outer inclined surface 16 and the upper end surface of the panel portion 2 inside the annular recess 15 are located at substantially the same height.

  The annular recess 15 described above can be formed as described below. FIG. 3 conceptually shows the molding die, and a die 19 on which a can lid intermediate material in which the annular groove portion 3, the corner portion 6, the panel portion 2, and the like are formed in advance, and the can lid intermediate material are processed. And a punch 20 to be applied. The die 19 is provided with a set recess 21 into which the annular groove 3 is inserted, and is fitted into the corner 6 of the can lid intermediate material from the inside at a position adjacent to the set recess 21 on the inner peripheral side. An annular first ridge portion 22 is provided. A second ridge 23 having the same shape as the first ridge 22 is provided at a position separated from the first ridge 22 by the dimension corresponding to the width of the annular recess 15 toward the inner periphery. Therefore, the space between the first and second ridges 22 and 23 is recessed in the shape of an annular groove to form a molding recess 24. The portion on the center side from the second ridge portion 23 is sufficiently low so that the panel portion 2 is not sandwiched between the punch 20.

  On the other hand, the portion of the outer periphery of the punch 20 that faces the setting recess 21 enters the annular groove 3 of the can lid intermediate material, and the annular groove 3 is sandwiched between the setting recess 21 and the annular setting member. The ridge portion 25 is provided to hang down. An annular molding ridge 26 for molding the annular recess 15 by pressing the peripheral portion of the panel portion 2 into the molding recess 24 is provided at a position facing the molding recess 24 in the die 19. It has been. Further, at a position facing the center side portion from the second ridge portion 23, a pushing portion 27 having a flat shape and a smaller projection amount than the forming ridge portion 26 is provided. The push-in portion 27 is for preventing or suppressing the central portion of the panel portion 2 from bulging and deforming when the annular recess 15 is formed by the forming protrusion 26.

  Therefore, if the punch 20 is lowered to the bottom dead center in a state where the can lid intermediate material is set on the die 19, the forming protrusion 26 is the first and second protrusions of the panel portion 2. The portion between the portions 22 and 23 is pushed down, and as a result, the annular recess 15 is formed. In that case, since the pushing portion 27 of the punch 20 presses the central portion of the panel portion 2, the bulging deformation of this portion can be prevented or suppressed.

  As described above, the outer inclined surface 16 of the annular recess 15 in the can lid 1 according to the present invention is connected almost directly to the corner portion 6 that connects the inner wall surface 5 of the annular groove 3 and the panel portion 2. Thus, the angle formed by the inner wall surface 5 of the annular groove portion 3 and the outer inclined surface 16 of the annular recess 15 that is the peripheral portion of the panel portion 2 can be an acute angle smaller than 90 °. Therefore, the strength can be improved by bending the corner portion 6 that connects the annular groove portion 3 and the outer inclined surface 16 of the annular recess 15, and even if an internal pressure is applied to the can lid 1 of the canned beverage, The angle formed with the outer inclined surface 16 of the annular recess 15 is difficult to open, and the bulging deformation of the central portion of the can lid 1 can be suppressed. Therefore, it is possible to prevent the tab 10 from coming into contact with the carton case and the score line 8 from being broken due to vibration during transportation or the score line 8 from being broken due to an inadvertent impact on the carton case. Moreover, when the canned beverage after filling is inverted and conveyed on the filling line of the contents, the canned beverage can be prevented from becoming unstable.

  Further, since the annular recess 15 has the outer inclined surface 16 and the inner inclined surface 18, the strength due to bending of the corner portion 6 that connects the inner wall surface 5 of the annular groove 3 and the outer inclined surface 16 of the annular recess 15. In addition to improving the strength of the annular recess 15 itself by bending the outer inclined surface 16 and the inner inclined surface 18, the strength of the peripheral portion of the panel portion 2 can be further improved, and the central portion of the can lid 1 can be sufficiently improved. The bulging deformation can be suppressed, and furthermore, by forming the annular recess 15, the flat region of the panel portion 2 is narrowed, so that the bulging deformation at the central portion of the can lid 1 is further suppressed. .

  In particular, it is preferable that the angle formed by the inner wall surface 5 of the annular groove connected to the panel portion 2 and the outer inclined surface 16 of the annular recess 15 is 45 ° to 80 °, thereby causing the performance of the can lid 1 to deteriorate. This can sufficiently suppress the bulging deformation. That is, when this angle is smaller than 45 °, the corner portion 6 that connects the inner wall surface 5 of the annular groove and the outer inclined surface 16 of the annular recess 15 is bent and the partial thickness of the can lid 1 is reduced. There is a possibility that thinning or deterioration of inner surface quality may occur. If the angle is greater than 80 °, the strength of the corner portion 6 is not sufficiently improved by bending, and the swelling deformation of the central portion of the can lid 1 is sufficiently suppressed. May not be done.

  Here, as an example of specific dimensions, in this embodiment, the width between the upper ends of the inclined surfaces of the annular recess 15 is 1.86 mm, and the depth from the upper surface of the panel portion 2 to the bottom surface 17 of the annular recess 15 is shown. The depth is 0.38 mm, and the depth of the annular recess 15 is preferably in the range of 0.2 mm to 0.6 mm, so that sufficient bulging deformation can be reliably prevented while preventing bulging deformation. it can. That is, if it is shallower than 0.2 mm, sufficient strength cannot be improved and bulging deformation may not be suppressed when an internal pressure is applied. If it is deeper than 0.6 mm, the metal constituting the annular groove 3 when the annular recess 15 is formed. There is a possibility that the material is pulled, a predetermined shape cannot be obtained, and the pressure resistance is lowered.

  Further, in this embodiment, in order to prevent the central portion of the panel portion 2 from slightly expanding when the annular recess 15 is formed, at the same time as the annular recess 15 is formed by a press die, The panel surface in the range is pushed down by about 0.05 to 0.3 mm by the indentation molding part of the mold.

  The present invention is not limited to the specific examples described above. For example, the shape of the tab is arbitrary, and the method of forming the annular recess 15 is not limited to the above specific examples.

It is a top view which shows an example of the easy opening can lid which concerns on this invention. It is a longitudinal cross-sectional enlarged sectional view of a part of the outer periphery of the can lid. It is a conceptual diagram which shows typically the state which shape | molds the annular recessed part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Can lid, 2 ... Panel part, 3 ... Circular groove part, 4 ... Flange part, 5 ... Inner wall surface, 6 ... Corner part, 8 ... Score line, 9 ... Opening piece, 10 ... Tab, 12 ... Finger hook part, 15 An annular recess, 16 an outer inclined surface, 18 an inner inclined surface.

Claims (2)

A substantially disk-shaped panel portion, an annular groove portion disposed at the peripheral edge portion of the panel portion, and a flange portion for fixing the can body disposed at the outer peripheral edge portion of the annular groove portion are integrally formed, The panel portion is formed with an opening piece defined by a score line and a tab fixed to the substantially central portion of the panel portion where the opening piece can be opened by pulling up one end side as a finger hanging portion. In
An annular recess is formed in the vicinity of the peripheral edge of the panel portion and on the inner peripheral side of the annular groove portion along the annular groove portion, and the annular recess opens substantially in a V shape on the upper surface side of the panel portion. An outer inclined surface on the outer side in the radial direction of the lid and an inner inclined surface on the inner side in the radial direction of the can lid, and the outer inclined surface is substantially at a corner portion connecting the annular groove portion and the panel portion. Connected ,
The annular groove has a inner wall surface continuously provided on the corner portion, the opening angle between the outer inclined surface of the inner wall surface and the annular recess, characterized in that it is a range of 45 ° to 80 ° facilitating Can lid. Before Kisotogawa inclined surface and the corner portion, the opening easily can lid according to claim 1, characterized in that it is continuously provided by a curved surface which is convex on the upper side of the panel portion.

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