Patent Publication Number: US-9850024-B2

Title: Can lid and beverage can

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a National Stage of International Application No. PCT/JP2013/078196 filed Oct. 17, 2013, claiming priority based on Japanese Patent Application No. 2012-245444 filed Nov. 7, 2012, the contents of all of which are incorporated herein by reference in their entirety. 
     TECHNICAL FIELD 
     The present invention relates to a can lid and a beverage can. 
     BACKGROUND ART 
     A beverage can in which breakage of a panel is caused at a score line by a press of part of the panel by a tab to thereby form an opening that functions as a place a person drinks from is suggested (for example, refer to Patent Document 1). 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Document 1: Japanese Patent Application Laid-Open Publication No. 51-82188 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     A beverage can in which breakage of a panel is caused at a score line by a press of part of the panel by a tab to thereby form an opening that functions as a place a person drinks from is known. Here, in such a beverage can, by further operating the tab after the breakage of the panel is caused, a tongue-shaped broken section produced by the breakage of the panel is pressed into the inside of the beverage can, and thereby the opening is formed. 
     An object of the present invention is to provide a can lid or the like that is capable of smoothly breaking a panel and smoothly pressing a broken section, which is produced by breakage of the panel, by a tab. 
     Solution to Problem 
     A can lid, to which the present invention is applied, includes: a panel that includes an outer peripheral edge and is attached to an aperture of a can barrel; a tab that includes a first edge section, a second edge section on a side opposite to the first edge section, a first side edge formed to head for the second edge section from the first edge section, and a second side edge formed to head for the second edge section from the first edge section and arranged on a side opposite to the first side edge, the tab being operated by a user, when an opening is formed in the panel, to move in a direction in which the first edge section side is apart from the panel; and a connecting section that connects a portion of the tab positioned between the first edge section and the second edge section and the panel, wherein the tab is provided with: a first through hole that is provided between the first edge section and the connecting section; a second through hole that is formed to include one end section closer to a side, on which the second edge section is provided, than the connecting section, and is formed to pass between the connecting section and the first side edge and also between the first through hole and the first side edge to head for the first edge section side from a location where the one end section is positioned, the second through hole being formed so that at least a part thereof heads for the second side edge side and the other end section is located in a region positioned between the first through hole and the first edge section; and a third through hole that is formed to include one end section closer to a side, on which the second edge section is provided, than the connecting section, and is formed to pass between the connecting section and the second side edge and also between the first through hole and the second side edge to head for the first edge section side from a location where the one end section is positioned, the third through hole being formed so that at least a part thereof heads for the first side edge side and the other end section is positioned in the region located between the first through hole and the first edge section. 
     Here, the connecting section connects a portion positioned on a center line of the tab and the panel, the portion being positioned on the center line heading for the second edge section side from the first edge section side, the first through hole is provided on the center line of the tab, and formed into a linear symmetrical shape with respect to the center line as a symmetrical axis, and one through hole of the second through hole and the third through hole is formed in one of two regions facing with the center line interposed therebetween, and the other through hole is formed on the other of the two regions, the second through hole and the third through hole being arranged in a linear symmetrical relation with respect to the center line as a symmetrical axis. In this case, it becomes possible to suppress unstable behavior of the tab. 
     Moreover, the first through hole is formed to draw a circular arc around a location where the connecting section is provided. In this case, it is possible to make concentration of stress that possibly occurs in the tab less likely to be caused, as compared to a case in which the first through hole is formed to be bent. 
     Moreover, the second through hole and the third through hole are formed to draw circular arcs around the location where the connecting section is provided. In this case, it is possible to make concentration of stress that possibly occurs in the tab less likely to be caused, as compared to a case in which the second through hole and the third through hole are formed to be bent. 
     Moreover, the second through hole and the third through hole, which are formed to draw the circular arcs, are provided to pass through a location which is separated from the connecting section by a first separation distance, and are formed so that the first separation distance is larger than a separation distance between the first through hole and the connecting section, the second through hole and the third through hole extending to the region positioned between the first through hole and the first edge section. In this case, as compared to a case in which the second through hole and the third through hole do not extend to the region positioned between the first through hole and the first edge section of the tab, it becomes possible to reduce a load, which is applied to a portion of the connecting section positioned on the first edge section side and is applied when operation of the tab is started by the user. 
     Moreover, in a case where the present invention is captured as a beverage can, a beverage can, to which the present invention is applied, includes: a can barrel that includes an aperture and contains a beverage inside thereof; and a can lid with which the aperture of the can barrel is covered, wherein the can lid includes: a panel that includes an outer peripheral edge and is attached to the aperture of the can barrel; a tab that includes a first edge section, a second edge section on a side opposite to the first edge section, a first side edge formed to head for the second edge section from the first edge section, and a second side edge formed to head for the second edge section from the first edge section and arranged on a side opposite to the first side edge, the tab being operated by a user, when an opening is formed in the panel, to move in a direction in which the first edge section side is apart from the panel; and a connecting section that connects a portion of the tab positioned between the first edge section and the second edge section and the panel, wherein the tab is provided with: a first through hole that is provided between the first edge section and the connecting section; a second through hole that is formed to include one end section closer to a side, on which the second edge section is provided, than the connecting section, and is formed to pass between the connecting section and the first side edge and also between the first through hole and the first side edge to head for the first edge section side from a location where the one end section is positioned, the second through hole being formed so that at least a part thereof heads for the second side edge side and the other end section is located in a region positioned between the first through hole and the first edge section; and a third through hole that is formed to include one end section closer to a side, on which the second edge section is provided, than the connecting section, and is formed to pass between the connecting section and the second side edge and also between the first through hole and the second side edge to head for the first edge section side from a location where the one end section is positioned, the third through hole being formed so that at least a part thereof heads for the first side edge side and the other end section is positioned in the region located between the first through hole and the first edge section. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide a can lid or the like that is capable of smoothly breaking a panel and smoothly pressing a broken section, which is produced by breakage of the panel, by a tab. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top view of a beverage can to which an exemplary embodiment is applied; 
         FIG. 2  is a front view showing a state of a panel before a tab is attached; 
         FIGS. 3A to 3E  are diagrams for illustrating states of the panel; 
         FIG. 4  is a diagram for illustrating breakage caused in the panel; 
         FIGS. 5A to 5D  are diagrams showing other examples of a shape of a groove; 
         FIG. 6  is a diagram showing another configuration example of the panel; 
         FIGS. 7A to 7D  are diagrams for illustrating a configuration of the tab; 
         FIGS. 8A to 8D  are diagrams showing movement of the tab when an opening is formed in the beverage can; 
         FIGS. 9A and 9B  are diagrams in a case where the beverage can is viewed from above; and 
         FIG. 10  is a diagram showing another configuration example of a can lid. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, an exemplary embodiment according to the present invention will be described in detail with reference to attached drawings. 
       FIG. 1  is a top view of a beverage can  100  to which the exemplary embodiment is applied. As shown in the figure, the beverage can  100  includes a container body (can barrel)  200  that is formed in a cylindrical shape and has an aperture at an upper portion and a bottom section at a lower portion, and a can lid  300  that is attached to the aperture of the container body  200  to cover the aperture of the container body  200 . It should be noted that the beverage can  100  is filled with (contains) a drink (contents), such as a soft drink, a carbonated drink or an alcoholic beverage. 
     The can lid  300  includes a panel  400  that is formed into a disk shape and functions as a substrate. Moreover, the can lid  300  includes a tab  500  to be operated by a user. Here, the tab  500  is attached to the panel  400 . In addition, the tab  500  is arranged along one direction from a peripheral edge section side of the panel  400  toward a rivet  900 . 
     Moreover, the tab  500  includes a first edge section  501  on one end section side in the longitudinal direction thereof and a second edge section  502  on the other end section side in the longitudinal direction, and, by user&#39;s operation such that the first edge section  501  side is moved in a direction away from the panel  400 , the second edge section  502  is pressed against a predetermined location of the panel  400  (to be described in detail later), to thereby press the panel  400 . It should be noted that the can lid  300  in the exemplary embodiment is a can lid of a so-called stay-on type, in which the tab  500  maintains a state of being attached to the panel  400  even after the opening that functions as a place a person drinks from is formed on the panel  400 . 
     Here, in the exemplary embodiment, the tab  500  is fastened to the panel  400  by the rivet  900  provided at a position deviated from a center section (center) of the panel  400 . To additionally describe, the tab  500  is fastened to the panel  400  by the rivet  900  provided in a decentered state with respect to the panel  400 . To describe further, the tab  500  is fastened to the panel  400  by the rivet  900  provided closer to the center section of the panel  400  than the location of the panel  400  pressed by the tab  500 . 
     Further, in the tab  500 , a portion positioned between the first edge section  501  and the second edge section  502  of the tab  500  is fastened to the panel  400  by the rivet  900 . Here, the location where the rivet  900  is provided is able to be grasped as a connecting section that connects the portion positioned between the first edge section  501  and the second edge section  502  of the tab  500  and the panel  400 . Moreover, the rivet  900  connects a portion positioned on a center line CL of the tab  500  (a virtual center line CL extending from the first edge section  501  side toward the second edge section  502  side along the longitudinal direction of the tab  500 ) and the panel  400 . 
     Here, in the exemplary embodiment, description is given by taking a mode in which the tab  500  is fastened to the panel  400  by the rivet  900  provided at the position deviated from the center section of the panel  400  as an example; however, the tab  500  may be fastened to the panel  400  by a rivet  900  provided at the center section of the panel  400 . Moreover, in  FIG. 1 , the tab  500  in which the second edge section  502  (a tip end section of the tab  500  (a tab nose)) was formed in a circular arc shape was exemplified; however, for example, it may be possible that the tab  500  is formed in a rectangular shape and the tip end section of the tab  500  is formed in a linear fashion. 
       FIG. 2  is a front view showing a state of the panel  400  before the tab  500  is attached. 
     The panel  400  is formed in a disk shape, as described above. Moreover, the panel  400  has an outer peripheral edge  410  in which bending was applied. In the exemplary embodiment, in a state where the outer peripheral edge  410  and an upper edge section (not shown) of the container body  200  are brought into contact with each other, so-called seaming processing is applied to the outer peripheral edge  410  and the upper edge section. This fastens the panel  400  to the upper edge section of the container body  200 . Moreover, in the panel  400 , a protruding section (nipple)  420 , which will be crushed when the tab  500  is fastened to the panel  400  to become the above-described rivet  900 , is formed. The protruding section  420  is provided at a location deviated from the center section CP of the panel  400 . 
     Moreover, on a surface of the panel  400 , a first score line  430  is formed. The first score line  430  is formed to enclose a region RA, of the panel  400 , pressed by the tab  500  (a pressed portion pressed by the tab  500 ). To additionally describe, the first score line  430  is formed around the region RA. Moreover, the first score line  430  is configured with a groove formed on the surface of the panel  400  and plays a role of inducing breakage of the panel  400  (to be described later). To additionally describe, the first score line  430  is able to be grasped as a breakage prediction line on which breakage of the panel  400  is predicted. 
     Moreover, the first score line  430  is formed to curve toward the outer peripheral edge  410  of the panel  400 , and is formed in substantially a U shape when the panel  400  is viewed from the front. Further, the first score line  430  includes one end section  431  and the other end section  432  on the center section CP side of the panel  400 , and a vertex section  433 A on the outer peripheral edge  410  side of the panel  400 . 
     The one end section  431  of the first score line  430  is arranged on one side of two regions that face each other with the center line CL (also refer to  FIG. 1 ) of the tab  500  interposed therebetween. To additionally describe, the one end section  431  is arranged on one side of two regions that face each other with the center line CL along the longitudinal direction of the tab  500  interposed therebetween. Moreover, the other end section  432  is arranged on the other side of two regions that face each other with the center line CL interposed therebetween. Moreover, in the exemplary embodiment, the first score line  430  is arranged to be linearly symmetric with respect to the center line CL of the tab  500  as a symmetrical axis. 
     Moreover, in the exemplary embodiment, by arranging the one end section  431  and the other end section  432  in a state of being separated from each other, between the one end section  431  and the other end section  432 , there is generated a state providing a discontinuous section where the first score line  430  is not provided. By providing the discontinuous section, a later-described tongue section is not separated from the panel  400 , and the tongue section is in a state of attaching to the panel  400 . It should be noted that, in the exemplary embodiment, the center line CL of the tab  500  passes through the center section CP of the panel  400  and the protruding section  420  formed on the panel  400 , as shown in  FIG. 2 . 
     In addition, in the exemplary embodiment, in a case where a first virtual line KL 1 , which is a virtual line that is orthogonal to the above-described center line CL and passes through the protruding section  420  (rivet  900 ), is assumed, the above-described one end section  431  and the other end section  432  are provided closer to the center section CP side of the panel  400  than the first virtual line KL 1 . To additionally describe, in  FIG. 1 , the one end section  431  and the other end section  432  are provided upward of the rivet  900 . Moreover, the vertex section  433 A is provided in one of two regions that face each other with a second virtual line KL 2 , which is a virtual line that is orthogonal to the above-described center line CL and passes through the center section CP of the panel  400 , interposed therebetween, and the one end section  431  and the other end section  432  are provided in the other region. Further, in the one region, the protruding section  420  is provided. 
     To describe further, the protruding section  420  that will become the rivet  900  is provided in a portion of the panel  400  enclosed by the first score line  430 , which is positioned closer to the vertex section  433 A side than the one end section  431  and the other end section  432  of the first score line  430 . Moreover, as shown in  FIG. 2 , the first score line  430  includes a curved section  433 . The curved section  433  is provided to connect the one end section  431  and the other end section  432 , swell toward a side on which the protruding section  420  is provided, and pass through closer to the outer peripheral edge  410  side of the panel than the protruding section  420 . 
     Moreover, the curved section  433  has the vertex section  433 A at a location crossing the center line CL. In addition, in the can lid  300  in the exemplary embodiment, in the region of the panel  400  enclosed by the first score line  430 , a reinforcing bead HB that increases stiffness of the region enclosed by the first score line  430  is formed. Moreover, on one end section of the reinforcing bead HB, an embossment EB, which protrudes upward (outward of the beverage can  100 ) and is pressed by the tip end of the tab  500 , is provided. By providing the embossment EB, breakage of the panel  400  on a second score line  450  (to be described in detail later) is likely to be caused, as compared to a case in which the embossment EB is not provided. 
     Here, in the exemplary embodiment, by operation of the tab  500  by a user, the region enclosed by the first score line  430  is pressed by the tab  500 , and accordingly, breakage of the panel  400  is caused on the location where the first score line  430  is formed (to be described in detail later). This causes the region on which the first score line  430  is formed to be in the tongue shape, and also causes the region to be bent toward the inside of the beverage can  100 . Consequently, an opening that plays a role of a place a person drinks from is formed in the beverage can  100 . It should be noted that, in this specification, hereinafter, the above-described tongue-shaped portion formed by breakage caused on the first score line  430  is referred to as a tongue section, in some cases. 
     Moreover, on the surface of the panel  400 , the second score line  450  is formed. It should be noted that the second score line  450  is also configured with a groove formed on the surface of the panel  400  and plays a role of inducing breakage of the panel  400 . Of the two regions facing each other with the first virtual line KL 1  interposed therebetween, the second score line  450  is provided in the region where the vertex section  433 A (the vertex section  433 A of the first score line  430 ) is provided. 
     Moreover, the second score line  450  includes one end section  451  and the other end section  452 . Here, the other end section  452  of the second score line  450  is connected to the curved section  433  of the first score line  430 . Accordingly, in the exemplary embodiment, the score line branches at a location where the first score line  430  and the second score line  450  are connected. 
     To describe the second score line  450  further, the other end section  452  of the second score line  450  is connected to a portion positioned between the center line CL and the first virtual line KL 1  in the curved section  433  of the first score line  430 . To describe further in detail, the other end section  452  of the second score line  450  is connected to a portion positioned between the vertex section  433 A and the other end section  432  of the first score line  430 . To describe further, the other end section  452  of the second score line  450  is connected to, of the first score line  430 , a location other than the location where the vertex section  433 A is provided. 
     To describe further, the connecting section of the first score line  430  and the second score line  450  is provided at a location other than a crossing location KP where the center line CL and the first score line  430  cross each other. Moreover, in the exemplary embodiment, the second score line  450  is provided to head toward the inside of the region enclosed by the first score line  430  from the connecting section with the first score line  430 . Moreover, in the exemplary embodiment, the connecting section of the first score line  430  and the second score line  450  is provided closer to a side where the above-described crossing location KP is provided than the first virtual line KL 1  arranged in a relation orthogonal to the center line CL. To describe further, the connecting section of the first score line  430  and the second score line  450  is provided closer to a side where the region RA is positioned than the first virtual line KL 1  arranged in a relation orthogonal to the center line CL. 
     Moreover, in the exemplary embodiment, the distance between the connecting section of the first score line  430  and the second score line  450  and the one end section  431  of the first score line  430  is larger than the distance between the connecting section and the other end section  432  of the first score line  430 . To additionally describe, the length of the portion positioned between the one end section  431  of the first score line  430  and the above-described connecting section is longer than the length of the portion positioned between the other end section  432  of the first score line  430  and the above-described connecting section. 
     It should be noted that, in the exemplary embodiment, the description has been given of a case where the second score line  450  is provided to head in the lower right direction in the figure; however, the second score line  450  may be provided to head in the lower left direction in the figure. In this case, the second score line  450  is connected to a portion positioned between the vertex section  433 A and the one end section  431  of the first score line  430 . 
     On the other hand, the one end section  451  of the second score line  450  is provided in proximity to the protruding section  420 . To describe further, the one end section  451  of the second score line  450  is arranged in one of the two regions facing with the centerline CL interposed therebetween, and the other end section  452  of the second score line  450  is arranged in the other one of the two regions. To describe further, the second score line  450  includes a linear section  453  heading for the protruding section  420  from the other end section  452 . Further, the second score line  450  includes a curved section  454 . The curved section  454  is arranged to be connected to the linear section  453 , and have a distance with the protruding section  420  formed into a circular-cylindrical shape, and is provided to be along the protruding section  420 . 
     Here, the curved section  454  is formed between the protruding section  420  and the first score line  430 . To describe in more detail, the curved section  454  is formed between the vertex section  433 A of the first score line  430  and the protruding section  420 . To additionally describe, on the center line CL, the curved section  454  of the second score line  450  is arranged between the protruding section  420  and the first score line  430 . 
     Moreover, the curved section  454  is provided to pass between the region RA, of the panel  400 , pressed by the tab  500  (the pressed portion pressed by the tab  500 ) and the protruding section  420 . To additionally describe, in the exemplary embodiment, the second score line  450  is provided to pass through closer to a side where the protruding section  420  (the rivet  900 ) is provided than the above-described region RA, and also the second score line  450  is provided to pass between the above-described region RA and the protruding section  420 . 
     Moreover, in the exemplary embodiment, the curved section  454  of the second score line  450  is provided to cross the above-described center line CL that passes through the region RA, which is pressed by the tab  500 , and the protruding section  420  (the straight line passing through the region RA and the protruding section  420 ). To describe further, the second score line  450  in the exemplary embodiment, after passing between the region RA and the protruding section  420 , travels along the direction crossing the center line CL, and is connected to the first score line  430 . To additionally describe, the second score line  450  in the exemplary embodiment is formed along the direction that crosses the direction of providing the center line CL. 
     To describe further, the second score line  450  traveling in the direction crossing the center line CL travels to gradually approach the side on which the region RA is positioned, of the side on which the region RA is positioned and the side on which the protruding section  420  is provided. More specifically, the second score line  450  travels toward the first score line  430  so that the linear section  453  of the second score line  450  gradually approaches the side on which the region RA is positioned. 
     To describe further, the second score line  450 , after passing between the region RA and the protruding section  420 , travels to be gradually separated from the first virtual line KL 1 , and is connected to the first score line  430 . It should be noted that, at this time, the second score line  450  passes beside the region RA. To additionally describe, the second score line  450 , after passing between the region RA and the protruding section  420 , travels to be gradually separated from the first virtual line KL 1 , which is a straight line orthogonal to the straight line passing the vertex section  433 A of the first score line  430  and the center section CP of the panel  400  and is a straight line passing through the protruding section  420 , travels aside the region RA, and is connected to the first score line  430 . 
     Here, also with reference to  FIGS. 3A to 3E  (a diagram for illustrating the states of the panel  400 ), the states of the panel  400  when the tab  500  is operated will be described. It should be noted that, in each of  FIGS. 3A to 3E , the diagram viewing the panel  400  from the front is shown. Moreover, in each of  FIGS. 3A to 3E , illustration of the tab  500  is omitted. 
     In the exemplary embodiment, when rear end section of the tab  500  is pulled up by a user, the second edge section  502  of the tab  500  (refer to  FIG. 1 ) presses the above-described region RA (refer to  FIG. 2 ) positioned between the curved section  454  of the second score line  450  and the vertex section  433 A of the first score line  430 . Then, when the region RA is pressed by the tab  500 , first, breakage of the panel  400  is caused on the curved section  454  of the second score line  450  provided to pass between the region RA and the rivet  900  (the protruding section  420 ) (refer to  FIG. 3B ). Thereafter, in the exemplary embodiment, breakage of the panel  400  proceeds along the second score line  450 , and there is generated a state in which the panel  400  is broken to the connecting section of the first score line  430  and the second score line  450 . 
     Here, in the exemplary embodiment, the score line branches at the above-described connecting section of the first score line  430  and the second score line  450 . Accordingly, after breakage of the panel  400  proceeded from the above-described curved section  454  of the second score line  450  to the above-described connecting section, in the exemplary embodiment, as shown in  FIG. 3C , breakage heading for the one end section  431  of the first score line  430  from the connecting section proceeds. Moreover, as shown in  FIG. 3D , breakage heading for the other end section  432  of the first score line  430  from the connecting section also proceeds. 
     Thereafter, the rear end section of the tab  500  is further pulled up by the user, and thereby breakage of the panel  400  to the one end section  431  and the other end section  432  of the first score line  430  further proceeds. This causes the region enclosed by the first score line  430  to become the above-described tongue section. In addition, the tongue section is bent at a basal part of the tongue section (the location positioned between the one end section  431  and the other end section  432  of the first score line  430 ), and as shown in  FIG. 3E , the tongue section enters into the inside of the beverage can  100 . Consequently, in the beverage can  100 , an opening that functions as a place a person drinks from is formed. It should be noted that, although detailed description will be given later, when the pulled-up tab  500  is returned to the original state, the tab  500  is bent. 
     Here, breakage of the panel  400  caused on the first score line  430  and the second score line  450  will be further described with reference to  FIG. 4  (a diagram for illustrating breakage caused in the panel  400 ). In the exemplary embodiment, as described above, by pulling up the rear end section of the tab  500  by a user, the above-described region RA (refer to  FIG. 2 ) positioned between the curved section  454  of the second score line  450  and the vertex section  433 A of the first score line  430  is pressed by the tab  500 . 
     To additionally describe, of the region enclosed by the first score line  430 , the region positioned on a side of the vertex section  433 A of the first score line  430  than the second score line  450  is pressed by the tab  500 . This causes, first, breakage of the panel  400  at the curved section  454  of the second score line  450 . Thereafter, breakage of the panel  400  proceeds along the second score line  450 , and then breakage proceeds to the connecting section (the crossing point) of the first score line  430  and the second score line  450 . 
     Thereafter, by further pressing the region RA (refer to  FIG. 2 ) of the panel  400  by the second edge section  502  of the tab  500 , breakage of the panel  400  proceeds along the first score line  430 , to thereby bring into a state in which breakage of the panel  400  is caused to the location indicated by the reference sign  4 C in  FIG. 4 . To additionally describe, there is caused a state in which breakage of the panel  400  is caused to the vicinity of the location where the first virtual line KL 1  (refer to  FIG. 2 ) that passes through the protruding section  420  and the first score line  430  cross each other. 
     This forms an opening in the region  4 A in  FIG. 4 . To additionally describe, by breakage of the panel  400  on the second score line  450  and breakage of the panel  400  in the portion of the first score line  430  positioned closer to the one end section  431  than the above-described connecting section, a small opening (hereinafter, referred to as a small opening) is formed in part of the panel  400 . 
     Next, in the exemplary embodiment, by further pulling up the rear end section of the tab  500  by the user, the tab  500  inters into the inside of the beverage can  100  through the above-described small opening. Then, at this time, the tab  500  comes to press the location indicated by the reference sign  4 E in  FIG. 4 . To additionally describe, the edge section of the small opening is pressed. To describe further, of the panel  400 , a region  4 B positioned above the location where the second score line  450  comes to be pressed. To describe further, a region positioned between the location of the first score line  430  positioned closer to the other end section  432  side than the above-described connecting section and the second score line  450  comes to be pressed by the tab  500 . 
     Accordingly, in the exemplary embodiment, breakage of the panel  400  proceeds along the first score line  430 , and the panel  400  is broken to the location indicated by the reference sign  4 D. To additionally describe, there is caused a state in which breakage of the panel  400  is caused to the vicinity of the location where the first virtual line KL 1  (refer to  FIG. 2 ) that passes through the protruding section  420  and the first score line  430  cross each other. To describe further, breakage of the panel  400  is caused in the portion of the first score line  430  positioned closer to the other end section  432  side than the above-described connecting section, and the panel  400  is broken to the location indicated by the reference sign  4 D. 
     Thereafter, in the exemplary embodiment, by further pulling up the rear end section of the tab  500  by the user, rotational moment comes to act on the above-described tongue section (detailed description will be given later), breakage of the panel  400  is further caused on the first score line  430 . Specifically, breakage of the panel  400  is caused in both of a first portion of the first score line  430  positioned between the above-described location indicated by the reference sign  4 C and the one end section  431  and a second portion of the first score line  430  positioned between the above-described location indicated by the reference sign  4 D and the other end section  432 . 
     Thereafter, as described above, the tongue section is bent at a basal part of the tongue section (the location positioned between the one end section  431  and the other end section  432  of the first score line  430 ), and as shown in  FIG. 3E , the tongue section enters into the inside of the beverage can  100 . Consequently, in the beverage can  100 , the opening is formed. 
     It should be noted that, in the exemplary embodiment, the first score line  430  is arranged in linearly symmetrical relation with respect to the center line CL as a symmetrical axis. Therefore, breakage of the panel  400  from the location indicated by the reference sign  4 C toward the one end section  431  and breakage of the panel  400  from the location indicated by the reference sign  4 D toward the other end section  432  are caused at substantially a same timing. To additionally describe, breakage of the panel  400  from the location indicated by the reference sign  4 C toward the one end section  431  and breakage of the panel  400  from the location indicated by the reference sign  4 D toward the other end section  432  proceed simultaneously. 
     Here, in the exemplary embodiment, as described above, breakage of the panel  400  is caused on the second score line  450 , first. Next, in the exemplary embodiment, breakage of the panel  400  is caused at the portion of the first score line  430  positioned between the above-described connecting section and the location indicated by the reference sign  4 C. Thereafter, breakage of the panel  400  is caused at the portion of the first score line  430  positioned between the above-described connecting section and the location indicated by the reference sign  4 D. To additionally describe, in the exemplary embodiment, breakage of the panel  400  from the above-described connecting section toward the one end section  431  of the first score line  430  and breakage of the panel  400  from the above-described connecting section toward the other end section  432  of the first score line  430  are not caused simultaneously, but breakage of the panel  400  is caused in a temporally-shifted state. 
     To describe further, in the exemplary embodiment, the connecting section of the first score line  430  and the second score line  450  is not positioned on the center line CL of the tab  500 , and the connecting section of the first score line  430  and the second score line  450  is positioned at a position deviated from the center line CL. Accordingly, breakage of the panel  400  from the connecting section toward the one end section  431  of the first score line  430  and breakage of the panel  400  from the connecting section toward the other end section  432  of the first score line  430  are not caused simultaneously, but breakage of the panel  400  is caused in a temporally-shifted state. 
     To describe in detail, breakage from the connecting section toward the one end section  431  is caused first, and breakage from the connecting section toward the other end section  432  is next caused. Accordingly, in the exemplary embodiment, as compared to a case where breakage of the panel  400  toward the one end section  431  and breakage of the panel  400  toward the other end section  432  are caused simultaneously, an operation load on the tab  500  when the opening is formed in the panel  400  is reduced. 
     To describe further, in the exemplary embodiment, when the tab  500  is operated by a user and the tip end section (the second edge section  502 ) of the tab  500  presses the panel  400 , the tip end section presses a portion positioned below the second score line  450  (a portion positioned closer to the vertex section  433 A than the second score line  450 ), but does not press a portion positioned above the second score line  450 . 
     To additionally describe, the exemplary embodiment does not have a configuration in which both of the portion positioned below the second score line  450  and the portion positioned above the second score line  450  are simultaneously pressed by the tab  500 , but has a configuration in which the tab  500  contacts the portion positioned below the second score line  450  only, and thereby only this portion is pressed by the tab  500 . To describe further, in the exemplary embodiment, the above-described region  4 B and the tab  500  are configured to be brought into contact after the above-described small opening is formed in the panel  400 . 
     Accordingly, in the exemplary embodiment, breakage of the panel  400  from the above-described connecting section toward the one end section  431  of the first score line  430  and breakage of the panel  400  from the above-described connecting section toward the other end section  432  of the first score line  430  are not caused simultaneously, but breakage of the panel  400  is caused in a temporally-shifted state. This reduces the operation load on the tab  500  when the tab  500  is pulled up, as compared to the case where breakage of the panel  400  is caused at the same time. 
     It should be noted that, in the exemplary embodiment, breakage of the panel  400  from the location indicated by the reference sign  4 C toward the one end section  431  and breakage of the panel  400  from the location indicated by the reference sign  4 D toward the other end section  432  are caused at substantially a same timing. By the way, when breakage is caused, the angle of the tab  500  with respect to the panel  400  becomes large. Therefore, in this case, the operation load on the tab  500  does not become so large, and accordingly, degradation in operability of the tab  500  is suppressed. 
     It should be noted that, in the exemplary embodiment, as shown in  FIG. 2 , a groove  600  is provided in the region positioned between the one end section  431  and the other end section  432  of the first score line  430 , though description thereof was omitted above. The groove  600  is formed to be curved to draw a circular arc, and is provided to head from the side on which the one end section  431  of the first score line  430  is provided toward the side on which the other end section  432  of the first score line  430  is provided. Consequently, in the beverage can  100  in the exemplary embodiment, bending of the tongue section is likely to occur. Moreover, in the exemplary embodiment, since the groove  600  is formed to be curved, the tongue section having been bent is hardly returned to the original state. 
     It should be noted that the groove  600  may have any one of the shapes shown in  FIGS. 5A to 5D . 
       FIGS. 5A to 5D  are diagrams showing other examples of the shape of the groove  600 . The groove  600  is, for example, as shown in  FIG. 5A , able to be formed into a shape including a first side surface  621  and a second side surface  622  having a relation of substantially being orthogonal to the surface of the panel  400 , and a flat bottom surface  623  connecting the first side surface  621  and the second side surface  622 . It should be noted that a bottom section of the groove  600  may be assigned with curvature as shown in  FIG. 5B . 
     Moreover, the groove  600  is able to be formed into a shape having a triangular cross section as shown in  FIG. 5C . Moreover, in the above description, stiffness of the basal part of the tongue section is decreased by forming the groove  600 ; however, as shown in  FIG. 5D , the stiffness may be decreased by applying bending processing to the basal part of the tongue section. Moreover, in the exemplary embodiment, as shown in  FIG. 4 , the groove  600  was formed to curve toward a side opposite to the side where the protruding section  420  is provided; however, the groove  600  may be formed to curve toward the side where the protruding section  420  is provided. It should be noted that, in the exemplary embodiment, the description was given to a mode in which the groove  600  was provided; however, the groove  600  is not necessarily required, and the groove  600  may be omitted. 
     Moreover, in the exemplary embodiment, as described above, a case in which the second score line  450  is provided to pass between, of the panel  400 , the region RA pressed by the tab  500  and the protruding section  420  was exemplified; however, the mode of arranging the second score line  450  is not limited to the mode like this. For example, as shown in  FIG. 6  (a diagram showing another configuration example of the panel  400 ), a second score line  450  that does not pass between the region RA and the protruding section  420  may be provided. Further, in the above description, the second score line  450  is depicted as substantially a straight line; however, the second score line  450  is not limited to the straight line, but may be a curved line or other line. 
     Next, the tab  500  will be described in detail. 
       FIGS. 7A to 7D  are diagrams for illustrating a configuration of the tab  500 .  FIGS. 8A to 8D  are diagram showing movement of the tab  500  when the opening is formed in the beverage can  100 . It should be noted that  FIG. 7A  is a front view of the tab  500  and  FIG. 7B  is a perspective view of the tab  500 . 
     The tab  500  in the exemplary embodiment includes, as shown in  FIGS. 7A and 7B , a tab main body section  520  that is formed into a rectangular shape and a plate-like shape. It should be noted that, in the exemplary embodiment, bending processing (curling processing) is applied to an outer peripheral edge of the tab main body section  520 , and accordingly, the outer peripheral edge of the tab main body section  520  is in a state of curling into the inside. To additionally describe, at the edge section provided all around the tab main body section  520 , curling sections are formed. Consequently, in the tab  500  in the exemplary embodiment, bending stiffness is increased. Moreover, the shape of the cross section of the bending processing in the outer peripheral edge of the tab  500  is not limited to substantially a circular shape, as in the exemplary embodiment; however, the shape may be an elliptic, rectangular, triangular or polygonal shape. 
     Further, in the tab  500 , a through hole (a finger hole)  530  in which user&#39;s finger is caught is formed on a side (a tab tail side) opposite to the side on which the second edge section  502  that presses the panel  400  is provided. It should be noted that the through hole  530  is able to be omitted. Moreover, in the tab  500 , an insertion hole  540  into which the protruding section  420  (refer to  FIG. 2 ) provided in the panel  400  is inserted is formed on the tip end section side (the second edge section side  502 ) of the tab  500 . 
     Moreover, in the exemplary embodiment, of the four curling sections provided all around the tab main body section  520 , in the curling section provided along the longitudinal direction of the tab  500 , a first curling section slit  521  is formed. To additionally describe, the tab  500  of the exemplary embodiment includes a first side edge  503  formed to head from the first edge section  501  toward the second edge section  502 , and a second side edge  504  that is formed to similarly head from the first edge section  501  toward the second edge section  502  and is arranged on a side opposite to the first side edge  503 , and in the exemplary embodiment, in the curling section provided along the second side edge  504 , the first curling section slit  521  is formed. 
     Moreover, of the four curling sections, in another curling section provided along the longitudinal direction of the tab  500 , a second curling section slit  522  is formed. To additionally describe, in the another curling section provided along the first side edge  503 , the second curling section slit  522  is formed. 
     Further, of the tab main body section  520 , in the portion positioned between the first curling section slit  521  and the second curling section slit  522 , a groove  523  is formed. Moreover, on the location where an end section of the first curling section slit  521  is positioned and the location where an end section of the second curling section slit  522  is positioned, punching processing in a circular shape is applied to relief concentration of stress. 
     Here, the first curling section slit  521 , the second curling section slit  522  and the groove  523  are provided in a state along the short direction of the tab  500 . Moreover, the first curling section slit  521 , the second curling section slit  522  and the groove  523  are arranged to be on the same straight line. In addition, the first curling section slit  521 , the second curling section slit  522  and the groove  523  are arranged between the insertion hole  540  and the through hole  530 . Here, in the exemplary embodiment, the first curling section slit  521 , the second curling section slit  522  and the groove  523  are formed in this manner, and accordingly, stiffness (bending stiffness) in the portions where these are formed is decreased. 
     In the exemplary embodiment, as the first curling section slit  521  and the second curling section slit  522  are observed, inside the slit processing, cross sections of the curling sections of the tab  500  having the same shape in a state of facing each other. At this time, if a load is applied in the direction to pull up the tab toward the first edge section  501  side of the tab  500 , in the first curling section slit  521  and the second curling section slit  522 , the above-described cross sections abut each other, and mutually receive loads in the compressing direction, to thereby compete against the above-described load in the pulling-up direction. This is because, when the tab  500  is pulled up to form the opening in the panel  400 , the tab  500  begins to be bent at a portion of the tab main body section  520  between the first curling section slit  521  and the second curling section slit  522 ; however, since the curling sections facing in the first curling section slit  521  and the second curling section slit  522  endure the above-described loads in the compressing direction, the bending is inhibited, and thereby the bending stiffness in the longitudinal direction of the tab  500  is secured, and the tab  500  is escaped being bent. As a result, the second edge section  502  side of the tab  500  presses the panel  400 , to thereby form the opening in the panel  400 . After the opening is formed, the pulled-up tab  500  stands substantially in the vertical direction to the panel  400 , and the first edge section  501  side of the tab  500  is brought into a state of protruding from the top surface of the panel  400 . Consequently, if a load in a direction of returning to the first edge section  501  side of the tab  500  in order to bend the first edge section  501  side in a direction opposite to the above-described pulling-up direction, bending is to start from a portion of the tab main body section  520  that connects the first curling section slit  521  and the second curling section slit  522 . However, since bending in this case is, different from the above-described case of pulling up, the bending in a direction to separate the cross sections of the curling sections of the tab  500 , the facing first curling section slit  521  and second curling section slit  522  are not a factor to inhibit the bending, and accordingly, the tab  500  begins to be bent at the portion of the tab main body section  520  between the first curling section slit  521  and the second curling section slit  522 . At this time, if the groove  523  has been formed, the above-described bending is likely to be made further. 
     Consequently, in the exemplary embodiment, if a load is applied to the rear end section side of the tab  500 , the tab  500  is bent. Accordingly, in the exemplary embodiment, when the tab  500  pulled up by a user is operated to be returned to the original state, the tab  500  is bent, to thereby maintain a state in which the tip end section side of the tab  500  is inserted into the inside of the beverage can  100 . It should be noted that, in the exemplary embodiment, the groove  523  is formed between the first curling section slit  521  and the second curling section slit  522  to decrease the stiffness in the portion; however, the stiffness is able to be decreased not only by forming such a groove, but also by applying the bending processing. Moreover, the groove  523  is not necessarily required, and the groove  523  may be omitted. 
     In addition, in the exemplary embodiment, in the tab main body section  520 , a first main body section slit  731  to a third main body section slit  733  are provided to penetrate through the tab main body section  520 . Here, the first main body section slit  731  to the third main body section slit  733  are formed to draw circular arcs along an outer peripheral edge of the insertion hole  540  that has been formed into a circular shape. To additionally describe, the first main body section slit  731  to the third main body section slit  733  are formed to draw the circular arcs around the location where the insertion hole  540  is provided (the location of the tab  500  connected to the panel  400 ). It should be noted that the shape of the first main body section slit  731  to the third main body section slit  733  is not limited to the circular arc shape. As necessary, the shape may be other than the circular arc, as shown in  FIGS. 7C and 7D . 
     In  FIG. 7C , each of the second main body section slit  732  and the third main body section slit  733  is configured with a first linear section  91  and a second linear section  92 . Here, the first linear section  91  is formed along the longitudinal direction of the tab  500 , and the second linear section  92  is formed along the short direction of the tab  500 . Moreover, the first main body section slit  731  is configured with a first linear section  93 , a second linear section  94  and a third linear section  95 . Here, the first linear section  93  and the second linear section  94  are formed along the longitudinal direction of the tab  500 . In addition, the third linear section  95  is formed along the short direction of the tab  500 , and connects the first linear section  93  and the second linear section  94 . 
     Moreover, in  FIG. 7D , similar to  FIG. 7C , the first linear section  91  and the second linear section  92  are provided; however, in  FIG. 7D , the second linear section  92  is arranged in a state of being inclined with respect to the longitudinal direction and the short direction of the tab  500 . In addition, in  FIG. 7D , the third linear section  95  (refer to  FIG. 7C ) is omitted, and the first linear section  93  and the second linear section  94  are arranged in a state of being inclined with respect to the longitudinal direction and the short direction of the tab  500 . 
     Here, as shown in  FIGS. 7A and 7B , the first main body section slit  731 , as an example of a first through hole, is provided on a side closer to the insertion hole  540  than the second main body section slit  732 , as an example of a second through hole, and the first main body section slit  731  is provided on a side closer to the insertion hole  540  than the third main body section slit  733 , as an example of a third through hole. Moreover, the second main body section slit  732  and the third main body section slit  733  are formed to draw circular arcs along the outer peripheral edge of the insertion hole  540 , as described above, and provided to pass through locations that are in the same distance from the insertion hole  540 . It should be noted that the same is true for the first main body section slit  731 , and thereby the first main body section slit  731  is provided to pass through locations that are in the same distance from the insertion hole  540 . 
     To describe further, the first main body section slit  731  is provided closer on the rear end section side (the first edge section  501  side) of the tab  500  than the insertion hole  540 . To additionally describe, the first main body section slit  731  is provided between the first edge section  501  and the insertion hole  540  of the tab  500 . 
     Moreover, each of the second main body section slit  732  and the third main body section slit  733  includes one end  751  and the other end  752 . Here, the one end  751  is positioned closer to the second edge section  502  side of the tab  500  than the insertion hole  540 . In addition, the other end  752  is positioned closer to the first edge section  501  side of the tab  500  than the insertion hole  540 . Moreover, the other end  752  is arranged at a position heading for the center line CL (also refer to  FIG. 1 ) between the first main body section slit  731  and the first edge section  501  of the tab  500 . To describe further, the other end  752  is provided in a region positioned between the first main body section slit  731  and the first edge section  501  of the tab  500 . 
     Moreover, the second main body section slit  732  is formed to pass beside one of the insertion hole  540  and the first main body section slit  731  from the location where the above-described one end  751  is positioned, and to head for, between the first main body section slit  731  and the first edge section  501  of the tab  500 , the center line CL of the tab  500 . To describe further, the second main body section slit  732  is formed to pass between the insertion hole  540  and the first side edge  503  of the tab  500  from the location where the above-described one end  751  is positioned, and between the first main body section slit  731  and the first side edge  503  of the tab  500 , to head for the first edge section  501  side of the tab  500 , and also head for the second side edge  504  side of the tab  500 . 
     Moreover, the third main body section slit  733  is also formed to pass beside one of the insertion hole  540  and the first main body section slit  731  from the location where the above-described one end  751  is positioned, and to head for, between the first main body section slit  731  and the first edge section  501  of the tab  500 , the center line CL of the tab  500 . To additionally describe, the third main body section slit  733  is formed to pass between the insertion hole  540  and the second side edge  504  of the tab  500  from the location where the above-described one end  751  is positioned, and between the first main body section slit  731  and the second side edge  504  of the tab  500 , to head for the first edge section  501  side of the tab  500 , and also head for the first side edge  503  side of the tab  500 . 
     In addition, in the exemplary embodiment, as described above, the other ends  752  are positioned between the first main body section slit  731  and the first edge section  501  of the tab  500  to head for the center line CL of the tab  500 , and the second main body section slit  732  and the third main body section slit  733  are in a state of extending between the first main body section slit  731  and the first edge section  501  of the tab  500  toward the center line CL of the tab  500  from the above-described one ends  751  as starting points. 
     To describe further, each of the second main body section slit  732  and the third main body section slit  733  formed to draw circular arcs is provided to pass through a location where the distance from the insertion hole  540  becomes larger than the first main body section slit  731 , and extends between the first main body section slit  731  and the first edge section  501  to a region approaching the center line CL of the tab  500 . To describe further, each of the second main body section slit  732  and the third main body section slit  733  is provided to pass through a location separated by a predetermined separation distance from the insertion hole  540  and to pass through a location where the separation distance becomes larger than the distance between the first main body section slit  731  and the insertion hole  540 , and extends between the first main body section slit  731  and the first edge section  501  to a region approaching the center line CL of the tab  500 . 
     Moreover, the first main body section slit  731  is provided on the center line CL of the tab  500  (also refer to  FIG. 1 ), and is formed into a shape that is linear symmetry with respect to the center line CL as the symmetrical axis. In addition, the second main body section slit  732  is arranged in one side of two regions facing each other with the center line CL of the tab  500  interposed therebetween, and the third main body section slit  733  is arranged in the other region side. Moreover, the second main body section slit  732  and the third main body section slit  733  are arranged in a relation of linear symmetry with respect to the center line CL of the tab  500  as the symmetrical axis. 
     Here, in the case where the first main body section slit  731  is formed in a shape of linear symmetry and the second main body section slit  732  and the third main body section slit  733  are provided in a relation of linear symmetry in this manner, when the tab  500  is pulled up by a user, inclination of the tab  500  is suppressed. To describe more specifically, inclination of the tab  500 , in which one end section side in the short direction of the tab  500  is positioned above the other end section side, hardly occurs. 
     Moreover, though description was omitted above, in the exemplary embodiment, the other end  752  of the second main body section slit  732  and the other end  752  of the third main body section slit  733  are not connected. Consequently, in the exemplary embodiment, between the other end  752  of the second main body section slit  732  and the other end  752  of the third main body section slit  733 , an intervening section  728  configured with the tab main body section  520  and intervening between the other end  752  of the second main body section slit  732  and the other end  752  of the third main body section slit  733  is provided. 
     With reference to  FIGS. 8A to 8D , movement of the tab  500  will be described. It should be noted that, in  FIGS. 8A to 8D , states of cross section of the tab  500  at the center line CL (refer to  FIG. 1 ) are shown. 
     In the beverage can  100  of the exemplary embodiment, first, a user&#39;s finger is inserted between the rear end section of the tab  500  and the panel  400 , and the rear end section of the tab  500  is pulled up as shown in  FIGS. 8A and 8B . Here, when the pulling up is performed, the rear end section side of the tab  500  is floated above the panel  400 . Moreover, in the tip end section side of the tab  500 , the tip end section side of the tab  500  except for the tip end that is in contact with the panel  400  is also floated above the panel  400 . This is because, as shown in  FIG. 7A  and  FIG. 8B , by forming the first main body section slit  731 , the region indicated by the reference sign  7 D was less susceptible to restraint by the insertion hole  540 , and since the other end sections of the second main body section slit  732  and the third main body section slit  733  extended between the first main body section slit  731  and the first edge section  501  side to the region heading for the center line CL of the tab  500 , the region indicated by the reference sign  7 D was given flexibility in deformation, and by pulling up the rear end section of the tab  500 , the intervening section  728  shown in  FIG. 7A  was separated from the panel  400 , the region of the reference sign  7 D became dependent of the tab main body section  520  to be deformable, and the region  7 D, which includes the intervening section  728  including the vicinity of both end sections of the first main body section slit  731 , was deformed to be curved, to thereby make the state of the above-described slit  731  as shown in  FIG. 8B  possible. Further, by forming the one ends  751  of the second main body section slit  732  and the third main body section slit  733  between the insertion hole  540  and the second edge section  502  side as shown in  FIG. 7A , bending of the tab  500  is started from the reference sign  7 E that connects the above-described one ends  751 , and accordingly, the tip end section side of the tab  500  is floated above the panel  400 . 
     Here, when the tip end section side of the tab  500  is floated above the panel  400 , as indicated by the reference sign  8 A in  FIG. 8B , of the tab main body section  520 , the portion positioned closer to the tip end section side of the tab  500 , except for the tip end that is in contact with the panel  400 , than the rivet  900  is to move upward. Consequently, with respect to a left end of the rivet  900  shown in  FIG. 8B , which is a portion of the rivet  900  positioned closer to the tip end section side of the tab  500 , a load to pull upward (refer to arrow  8 B in the figure) comes to act on. Moreover, in the case where the tab  500  is pulled up, the tip end section of the tab  500  is pressed against the panel  400 . 
     As a result, in the exemplary embodiment, a shearing force comes to act on the second score line  450  provided to pass between the tip end section of the tab  500  and the rivet  900 . Then, by the shearing force, at the location where the second score line  450  is provided, breakage of the panel  400  is caused. Then, by further performing pulling up of the rear end section of the tab  500 , breakage of the panel  400  is also caused on the first score line  430  as described above. 
     It should be noted that, as described above (as shown in  FIG. 7A ), in the exemplary embodiment, there is provided a configuration in which the one end  751  provided to each of the second main body section slit  732  and the third main body section slit  733  is positioned closer to the tip end section side of the tab  500  than the insertion hole  540 . Then, in the exemplary embodiment, since such a configuration is employed, the tip end section side except for the tip end of the tab  500  is floated above the panel  400 , and accordingly, as shown in  FIG. 8B , the whole tab  500  becomes inclined to the panel  400 . Then, by generating the inclination, the user&#39;s finger is able to be inserted between the rear end section of the tab  500  and the panel  400 . 
     To describe more specifically, in the exemplary embodiment, the one end  751  provided to each of the second main body section slit  732  and the third main body section slit  733  is positioned closer to the tip end section side of the tab  500  than the insertion hole  540 . Then, in this case, the region positioned between the one ends  751  and the insertion hole  540  (the region  7 A indicated by oblique lines in  FIG. 7A ) is floated above the panel  400  as indicated by reference sign  8 A in  FIG. 8B , when pulling up of the tab  500  is started. Then, the tip end section side except for the tip end of the tab  500  is floated above the panel  400 , and accordingly, the whole tab  500  becomes inclined to the panel  400 . 
     It should be noted that, in a case where the portion positioned in the above-described region  7 A does not exist (for example, in a case where the second main body section slit  732  and the third main body section slit  733  are formed shorter and the above-described one ends  751  are positioned more to the right in the figure than the positions shown in  FIG. 7A ), the tip end section side of the tab  500  is hardly floated above the panel, and accordingly, the rear end section side of the tab  500  is hardly floated above the panel  400 , too. Then, in this case, the user&#39;s finger is less likely to be inserted between the tab  500  and the panel  400 , and thereby operability of the tab  500  is prone to be decreased. 
     Here, though description was omitted above, in the exemplary embodiment, since the first main body section slit  731  (refer to  FIG. 8B ) is provided, the load from the tab  500  (the operation load from the user) is less likely to be transmitted to the rear end section side of the rivet  900  in the state of  FIG. 8B . To additionally describe, a force to pull up the rear end section side of the rivet  900  (of the rivet  900 , the portion positioned closer to the first edge section  501  side of the tab  500 ) upward in the figure is less likely to act on the rivet  900 . 
     Here, if the force to pull up the rear end section side of the rivet  900  comes to act on the rivet  900 , an operation force from the user begins to act more on a location distant from the second score line  450 , and therefore, breakage of the panel  400  on the second score line  450  is less likely to be caused. To described further, according to  FIG. 8B  showing the tab in which the slit  731  is provided, when the first edge section  501  side of the tab  500  is pulled up, a force, which is indicated by  8 B on the second edge section  502  side of the tab  500  in the rivet  900 , comes to act on the rivet  900 . On the other hand, according to  FIG. 8D  showing the tab, in which the slit  731  is not provided, when the tab  500  is pulled up, a force, which is indicated by  8 E on the rear end section side of the rivet  900 , comes to act on the rivet  900 . With respect to the breakage of the panel  400  on the second score line  450 , it is considered that, by applying the load  8 C on the panel  400  on the side of the second edge section  502  of the tab  500  and the load  8 B or  8 E on the rivet  900  in mutually opposite directions, a force in the shearing direction acts on the second score line  450  formed therebetween to break thereof. At this time, as the load  8 B and  8 E acting on the rivet  900  are compared, with respect to each of the positions where the load is applied,  8 E is a long distance from the position where the load  8 C is applied, as compared with  8 B. Accordingly, with respect to  8 E, as compared to  8 B, the force in the shearing direction applied to the second score line  450  becomes less likely to act on. 
     To additionally describe, by intensively applying the shearing force to the portion closer to the second score line  450 , breakage of the panel  400  on the second score line  450  is able to be caused with more efficiency; however, if the load comes to act more on the rear end section side of the rivet  900 , the load comes to act on a location distant from the second score line  450  (the operation load from the user is distributed), the breakage of the panel  400  on the second score line  450  is less likely to be caused. 
     Consequently, in the exemplary embodiment, by provision of the first main body section slit  731 , the operation load from the user transmitted to the rear end section of the rivet  900 . Further, by forming the one ends  751  of the second main body section slit  732  and the third main body section slit  733  between the insertion hole  540  and the second edge section  502  side of the tab  500 , or the like, the operation force from the user comes to act on the tip end section side of the rivet  900  intensively (the operation load from the user comes to intensively act on a location, which is closer to the second score line  450 ), the breakage of the panel  400  on the second score line  450  is likely to be caused. Then, in this case, the user is able to cause the breakage of the panel  400  with less operation load. 
     With reference to  FIG. 8C , the next stage will be described. 
     If the rear end section of the tab  500  is further pulled up by the user from the state shown in  FIG. 8B , breakage of the panel  400  is further caused, and accordingly, the panel  400  is broken to the above-described location indicated by the reference sign  4 C (refer to  FIG. 4 ) and the location indicated by the reference sign  4 D, of the first score line  430 . 
     Then, in the exemplary embodiment, by further pulling up the rear end section of the tab  500  by the user, as described above, breakage of the panel  400  further proceeds toward the basal part of the tongue section (toward the one end section  431  (refer to  FIG. 4 ) and the other end section  432  of the first score line  430 ). To additionally describe, breakage of the panel  400  is caused in both of the first portion positioned between the above-described location indicated by the reference sign  4 C and the one end section  431 , and the second portion positioned between the above-described location indicated by the reference sign  4 D and the other end section  432 . 
     Here,  FIG. 8C  shows a state of the tab  500  when breakage of the panel  400  is caused in both of the above-described first portion and the above-described second portion. When breakage of the panel  400  is caused in both of the first portion and the second portion, as shown in  FIG. 8C , the angle of the tab  500  with respect to the panel  400  is brought into a state of being larger, and the tip end section side of the tab  500  is brought into a state in contact with the panel  400 . 
     Then, when the tab  500  is pulled up from the state of  FIG. 8C , a force to pull the rear end section side of the rivet  900  upward comes to act on the rivet  900 . To describe specifically, when the tab  500  is further pulled up from the state of  FIG. 8C , the operation load from the user acts on the rear end section of the rivet  900  through the region  7 C indicated by oblique lines in  FIG. 7A , and thereby the rear end side of the rivet  900  is to move upward. 
     To describe further, according to  FIG. 7A , when the first edge section  501  side of the tab  500  is gradually pulled up, the intervening section  728  starts to move in the direction apart from the panel  400 . At this time, since part of the region indicated by the reference sign  7 D is coupled to the intervening section  728 , along with the movement of the intervening section  728 , the region indicated by the reference sign  7 D starts to move from the intervening section  728  in the direction gradually apart from the panel  400 . The region indicated by the reference sign  7 D is enclosed by the first main body section slit  731 , the second main body section slit  732  and the third main body section slit  733  so as to be less susceptible to restraint from the tab main body section  520 , and further, so as to be able to be dependent from the tab main body section  520  and deformable into a unique shape. Consequently, when the intervening section  728  is moved in the direction apart from the panel  400 , with this, the region of the reference sign  7 D is deformed while being curved so that the periphery of the first main body section slit  731  is left on the panel  400  side, and is further expanded with the intervening section  728  being regarded as a vertex section. As this state, in  FIG. 8B , a situation in which the tab main body section  520  including the region  7 D is separated from the panel  400  is shown. However, the above-described expansion is limited, and after the above-described expansion is stopped, the load to separate the intervening section  728  from the panel  400  comes to be transmitted to the region  7 C that is connected to the region of the reference sign  7 D. Since the region  7 C is connected to the first edge section  501  side of the tab  500  of the insertion hole  540 , into which the rivet  900  is fitted, part of the operation force from the user becomes a force to pull up the rear end section side of the rivet  900 , which is the right side of the rivet  900  shown in  FIG. 8C . Moreover, the force becomes a force to pull up the panel  400  on the right side of the rivet  900 . On the other hand, on the panel  400  on the left side of the rivet  900 , a force to press down the panel  400  by the tip end of the tab  500  is acting. 
     As a result, in the exemplary embodiment, the rotational moment indicated by arrow  8 D (refer to  FIG. 8C ) comes to act on the panel  400 , and by the rotational moment, the tongue section enters into the inside of the beverage can  100 . To additionally describe, breakage of the panel  400  is caused in both of the above-described first portion positioned between the above-described location indicated by the reference sign  4 C (refer to  FIG. 4 ) and the one end section  431 , and the above-described second portion positioned between the above-described location indicated by the reference sign  4 D and the other end section  432 , and the tongue section enters into the inside of the beverage can  100 . 
     Here, to recapitulate the load applied to the rivet  900 , the load  8 B shown in  FIG. 8B  is mainly a load applied to the tip end section side of the rivet  900  in the course of opening formation in the regions  4 A and  4 B in  FIG. 4 . When the opening in the regions  4 A and  4 B in  FIG. 4  is formed, the above-described expansion of the reference sign  7 D is stopped, and thereby the tab  500  is brought into a state of being pulled up to have a predetermined inclination. Thereafter, when the tab  500  is further pulled up, the load is mainly applied to the rear end section side of the rivet  900  through the region of the reference sign  7 D and the region  7 C. In this manner, the rotational moment  8 D shown in  FIG. 8C  comes to act. 
     It should be noted that, in the exemplary embodiment, the operation load from the user is transmitted to the rear end section of the rivet  900  by use of the intervening section  728  (refer to  FIG. 7A ). Here, in a case where the intervening section  728  is not provided, to additionally describe, in a case where the second main body section slit  732  and the third main body section slit  733  are connected, the tab  500  is to rotate around a straight line (refer to the straight line indicated by the reference sign  7 E in  FIG. 7A ) that passes through the one end  751  (refer to  FIG. 7A ) of the second main body section slit  732  and the one end  751  of the third main body section slit  733 . In such a case, the load applied to the rear end section of the rivet  900  is reduced, and thereby the rotational moment that acts on the above-described tongue section is decreased. 
     Here, in the exemplary embodiment, as described above, in an initial stage of operation of the tab  500  by the user, more load acts on the tip end section side of the rivet  900 . Consequently, the load intensively acts on the second score line  450 , and accordingly, breakage of the panel  400  on the second score line  450  is more likely to be caused. Then, in the exemplary embodiment, by further pulling up the tab  500 , the load that acts on the rear end section of the rivet  900  is increased, and accordingly, bending moment acts on the above-described tongue section. This allows the tongue section to enter into the inside of the beverage can  100 , and thereby the opening in the beverage can  100  becomes larger. 
     It should be noted that, in the exemplary embodiment, the other ends  752  of the second main body section slit  731  and the third main body section slit  733  are positioned between the first main body section slit  731  and the first edge section  501  of the tab  500  to head for the center line CL of the tab  500 . Consequently, in the exemplary embodiment, there is provided a configuration in which the second main body section slit  732  and the third main body section slit  733  extend between the first main body section slit  731  and the first edge section  501  of the tab  500  to a region heading for the center line CL of the tab  500  from the above-described one ends  751  as the starting points. 
     In the case of such a configuration, as compared to a case in which the second main body section slit  732  and the third main body section slit  733  do not extend to an area between the first main body section slit  731  and the first edge section  501 , it becomes possible to reduce the load to lift the rear end section of the rivet  900 . More specifically, it becomes possible to reduce the load applied to the rear end section side of the rivet  900  when the operation of the tab  500  is started. To describe further, it becomes possible to reduce the load applied to the rear end section side of the rivet  900  when breakage of the panel  400  on the second score line  450  is caused. Then, in this case, as described above, it becomes possible to make the load intensively act on the second score line  450 . 
     Here, in the exemplary embodiment, as described above, the operation load from the user acts on the rear end section of the rivet  900  through the portion of the region  7 C indicated by oblique lines in  FIG. 7A . Here, as in the exemplary embodiment, in the case where the second main body section slit  732  and the third main body section slit  733  extend between the first main body section slit  731  and the first edge section  501  of the tab  500  to head for the center line CL of the tab  500 , there is provided a state in which the first main body section slit  731  is positioned between the intervening section  728  that transmits the load from the rear end section side of the tab  500  to the tip end section side of the tab  500  and the rivet  900 . 
     To additionally describe, in the case where the second main body section slit  732  and the third main body section slit  733  extend between the first main body section slit  731  and the first edge section  501  of the tab  500  to head for the center line CL of the tab  500 , there is provided a state in which the first main body section slit  731  that makes the load to the rear end side of the rivet  900  less likely to be transmitted is positioned between the intervening section  728  and the rivet  900 . Then, in this case, the load applied to the rear end side of the rivet  900  when the operation of the tab  500  is started by the user is reduced. Then, in this case, as described above, the load intensively acts on the second score line  450 . 
     To check the process of opening formation in the panel  400  in the exemplary embodiment anew, first, by pulling up the rear end section of the tab  500  by the user, the tab  500  becomes inclined with respect to the panel  400 , and thereby a gap is formed between the rear end section of the tab  500  and the panel  400 . Refer to  FIG. 8B . 
     This is because, by the region  7 D formed by the second main body section slit  732  and the third main body section slit  733 , the stiffness of the tab main body section  520  on the rear end section side of the rivet  900  as shown in  FIG. 8D  is decreased, and the one ends  751  of the second main body section slit  732  and the third main body section slit  733  shown in  FIG. 7A  extend between the insertion hole  540  and the second edge section  502  side to form the region  7 A, to thereby make it possible for the region  7 A to be bent so that the vicinity of  8 A shown in  FIG. 8B  is separated from the panel  400 . 
     By the above-described gap, it is easy for the user to insert a finger. By pulling up the rear end section of the tab  500  by the inserted finger, the tip end section of the tab  500  presses the panel  400  to start breakage of the panel  400 . Thereafter, breakage of the panel  400  is further caused, and accordingly, the panel  400  is broken to the location of the first score line  430  indicated by the reference sign  4 C (refer to  FIG. 4 ) and the location of the first score line  430  indicated by the reference sign  4 D. At this time, in the rivet  900 , the load from the tab  500  (the operation load from the user) acts on the tip end section side of the rivet  900 . 
     In a case where the region of the reference sign  7 D is observed in  FIG. 7A , when the tab  500  is pulled up, the intervening section  728  connected to the tab main body section  520  is lifted. To put another way, by pulling up the tab  500 , the region of the reference sign  7 D is lifted from the intervening section  728  side. In the region of reference sign  7 D at this time, since the intervening section  728 , which is one end section, is lifted while both end sections side of the first main body section slit  731 , which is the other end section, is left on the panel  400  side, the region of the reference sign  7 D expands with curvature deformation while the intervening section  728  being regarded as a vertex section. At this point of time, due to the above-described expansion, the load from the tab  500  is less likely to act on the rear end section side of the rivet  900 . 
     On the other hand, as indicated by  8 B in  FIG. 8B , the load from the tab  500  acts on the tip end section side of the rivet  900  as a reactive force of the press of the panel  400  by the tip end of the tab  500 . Thereafter, breakage of the panel  400  further proceeds, and thereby, the panel  400  is broken to the above-described location of the first score line  430  indicated by the reference sign  4 C (refer to  FIG. 4 ) and the location of the first score line  430  indicated by the reference sign  4 D. During the course until now, mainly, the load from the tab  500  acts on the tip end section side of the rivet  900 , and thereby breakage of the panel  400  proceeds. On the other hand, due to expansion of the above-described region of the reference sign  7 D, the load from the tab  500  is less likely to act on the rear end section side of the rivet  900 . 
     However, since the expansion of the region of the reference sign  7 D is limited because of being associated with the curvature deformation, after expansion of a predetermined amount, the region  7 D is hardly expanded further, and therefore, the load from the tab  500  is transmitted to the region  7 C by way of the region of the reference sign  7 D, to thereby act on the rear end section side of the rivet  900 . To describe further, the load from the tab  500  mainly acts on the tip end section side of the rivet  900  in substantially the first half of the opening process, and also acts on the rear end section side of the rivet  900  in substantially the second half. As the panel  400  around the rivet  900  in the above-described second half is observed, since the tip end of the tab  500  continues to press the panel  400  of the tip end section side of the rivet  900 , as shown in  FIG. 8C , rotational moment  8 D comes to act on the panel  400  around the rivet  900 . The rotational moment  8 D breaks the score that leads to the region of the one end section  431  from the reference sign  4 C shown in  FIG. 4  and that leads to the other end section  432  from the reference sign  4 D and acts to bend the region enclosed by the above-described score and insert thereof into the can, to thereby form the opening in the panel  400 . 
     It should be noted that, though the description was omitted above, when the tongue section enters into the inside of the beverage can  100 , as shown in  FIG. 9A  ( FIGS. 9A and 9B  are diagrams in a case where the beverage can  100  is viewed from above), the tip end section side of the tab  500  enters into the inside of the beverage can  100 . It should be noted that  FIG. 9A  shows a state in which the tab  500  stands up and the panel  400  and the tab  500  are orthogonal. Thereafter, the pulled-up tab  500  is to be returned to the original state by the user, and on this occasion, bending of the tab  500  is caused at the first curling section slit  521  (refer to  FIGS. 7A to 7D ), the second curling section slit  522  and the groove  523 , which have been described above. 
     As a result, in the exemplary embodiment, as shown in  FIG. 9B , the rear end section side of the tab  500  lies along the panel  400 . On the other hand, the tip end section side of the tab  500  is in a state of entering into the inside of the beverage can  100 . Here, when the pulled-up tab  500  is to be returned to the original state by the user, if bending of the tab  500  is not caused, part of the opening having been formed is blocked by the tip end section side of the tab  500 . In the case of exemplary embodiment, the tip end section side stays inside of the beverage can  100 , and thereby overlapping of the opening and the tab  500  becomes small. 
     It should be noted that, though the mode in which the second score line  450  is provided on the panel  400  was described above, a mode in which the second score line  450  is omitted is available. Specifically, for example, as shown in  FIG. 10  (a diagram showing another configuration example of the can lid  300 ), there can be a configuration in which one end section of the first score line  430  is extended, and the extended portion of the first score line  430  passes between the protruding section  420  and the vertex section  433 A. 
     REFERENCE SIGNS LIST 
     
         
           100  . . . Beverage can 
           200  . . . Container main body (can barrel) 
           300  . . . Can lid 
           400  . . . Panel 
           410  . . . Outer peripheral edge 
           500  . . . Tab 
           501  . . . First edge section 
           502  . . . Second edge section 
           731  . . . First main body section slit 
           732  . . . Second main body section slit 
           733  . . . Third main body section slit 
           751  . . . One end 
           900  . . . Rivet