Patent Publication Number: US-2010108679-A1

Title: Can, and a Body and Panel Therefor

Description:
The present invention relates to a can, and to a body and a panel therefore. 
     This can according to the invention may be of the type having a so-called easy opening closure. An easy opening closure is a metal closure for a can in which an opening may be formed by using one or more fingers and without the, requirement of a separate opening tool. To that extent the can is provided with a tab for forming an opening in the panel of the can. The tab functions as a lever. 
     The tab comprises a rear tab part which is to be gripped by the user. By levering or tilting of the tab the front tab part is actuated. Actuation by levering or tilting results in popping an initial opening in the panel. The opening is defined by a score line. The score line is generally circumferential. With the tab in an upright position a maximum popping opening is formed. Tearing the tab outwardly results in scoring out of the panel. Finally, by hinging the panel is torn apart from the can and the can opening is formed. 
     The can according to the invention may also be provided with a smaller opening by the levering action of the tab, thereby forming a small opening just sufficient for emptying the content of the can. 
     Users of the types of can described above appreciate sometimes a problem in gripping the rear tab part. Normally, this required that a nail or finger tip is inserted in between the panel and the rear tab part for starting the gripping action. 
     The invention has for its object to improve the initial gripping action by the user. This improvement is under the condition that other functions of the can and tab are not influenced, such as the manufacture, filling, handling and opening of the can by the tab. 
     The present invention is based on the insight that cans may have, after filling and closure, an internal pressure, which is different from the surrounding atmospheric pressure. There may be a negative pressure difference over the panel. Such negative pressure difference may be the result of hot filling and/or cooking of the content of the can before closing it. After closure and cooling the gas phase above the content will reduce in volume, thereby forming a negative pressure difference over the panel and the surrounding. A positive pressure difference may result from a permanent or transitional pressure build up after closure due to desired or unwanted gas generation and/or volume expansion due to heating. This pressure difference is used to have the panel acquire a depressed or concave form at least beneath the rear tab part. This depressed or concave forms result in an increase of the space beneath the rear tab part. The increased space improves the gripping action. Obviously, this panel change occurs after manufacture of can and panel, after filling and closing. There is substantially no interference with the traditional handling of such cans. 
     The change from the concave form into the convex form may occur as a result the changed pressure difference. However, the invention also encompasses the alternative after the change in pressure the changed in form does not yet take place but requires an impact from the outside, such as a mechanical contact or other physical means (magnets) by which the change in from will be facilitated. 
     It is noted that when the pressure difference is substantially zero the panel may be in the concave or convex form dependent on the structure of the panel. Thus, the pressure difference may result from internal and external pressures of which one or both are above or below atmospheric pressure. At zero pressure difference the panel may be in a concave or convex form. 
     Accordingly, the present invention provides a can, comprising a body provided with a panel, wherein the panel is provided with a tab comprising a front tab part and a rear tab part for gripping in forming by engagement of the front tab part with the panel of an opening in the panel, wherein the panel is provided with a flip panel area at least beneath the rear tab part, which panel area forms a depression beneath the rear tab part, which depression preferably has a concave form dependent on a pressure difference over the panel. The flip panel may be formed by providing the panel with a particular material (such as steel and aluminium), structure and/or by providing the panel in the flip panel area with a different thickness. The main influence factor, from all the material properties, is the Young modules (elastic). Furthermore, it is noted that two panel geometries may be identical but due to different manufacturing methods, their residual stress fields may be different which interacts with material properties. In essence it is required that the flip panel area has a higher flexibility than other parts of the panel such that by the pressure difference the concave form beneath the rear tab part is provided. 
     It is noted that jars, cans and bottles for fruit juice and marmalades may be provided with a screw cap having a similar flip panel area. However, these screw caps are not provided with a tab. 
     According to a first embodiment the flip panel area flips between a concave form and a flat form dependent on the pressure difference over the panel. 
     Thus, when the pressure difference is neutralized the flip panel parts flips from a concave form to a substantially flap form. 
     According to another embodiment the flip panel area flips between a concave form and a convex form dependent on a pressure over the panel. The provision of a convex form to the flip panel part does not interfere with the opening action using the tab because the tab is than in a more tilted position remote from the flip panel area. In relation to these embodiments it is noted that the pressure difference may be 
     According to a preferred embodiment the flip panel area is part of a terrace structure. Accordingly, there is a better controlled area in the terrace structure in which the flipping of the flip panel part could take place. In this respect it is preferred on a consumer perspective that the flip panel area is a central terrace structure. 
     According to another embodiment the panel is provided with a slanted or gradually depressing form (when the pressure difference exists). However, when the pressure difference is completely or partially neutralized the flip panel area flips from the slanted concave form to a flat or convex form. 
     In order to or precisely define or limit the substantial horizontal position of the tab prior to the opening of the can, it is preferred that the tab movement is limited by a panel rest structure. According to an embodiment the panel structure has the form of a dimple on which the tab may rest or by which dimple the downward movement of the tab part is limited. Although it is preferred that the flip panel area is located in the central panel part, other locations off-centered are also suitable. 
     It is noted that preferably the pressure difference at which the transition from convex to concave occurs is preferably a negative pressure difference. 
     The panel may be connected to the body of the can by any known means. The panel may be unitary with the body or may be connected by any means, such as soldering, seaming and the like. It is preferred that the panel is seamed to the can body. 
     An other aspect of the present invention relates to a body provided with a panel having a flip panel area, which has a concave form dependent on the pressure difference over the panel. 
     Finally, a last aspect of the invention relates to a panel which has a flip panel area which has a concave form dependent on a pressure over the panel when part of a can described above. 
    
    
     
       Mentioned and other features of the can, body and panel according to the invention will be further illustrated by way of the following examples which are given for illustrative purposes and not intended to limit the present invention to any extent, while making reference to the following drawings. 
       In the drawings is: 
         FIG. 1  a perspective view of a can according to the invention; 
         FIGS. 2A and 2B  a cross section following line II-II given in  FIG. 1  and showing the flipping of the flip panel area according to the invention; 
         FIGS. 3A and 3B  showing an alternative of the can according to the invention; 
       FIGS.  4 A/ 4 B and  5 A/ 5 B show other alternatives; 
       FIGS.  6 A/ 6 B/ 6 C show other alternatives of which  FIG. 6D  if an explanatory top view; and 
         FIGS. 7 and 8  shows still another alternatives of the easy opening panel of the invention. 
     
    
    
       FIG. 1  shows a can  1  according to the invention. The can comprises a body  2 , a top panel  3  and a bottom panel  4 . Top panel  3  and bottom panel  4  are seamed via a seam connection  5  to the body  2 . 
     The top panel  3  is provided with a traditional tab  6 . The tab  6  comprises a front tab part  7  and a rear tab part  8 . The rear tab part  8  is provided with an opening  9  into which a finger of the user may be inserted. 
     The tab  6  is connected to the top panel  3  via a rivet  10 . Other methods for connection of the tab  6  include welding with metal or plastic welding material. The rivet  10  may be a separate rivet or may have been formed of material originating from the top panel and formed into a rivet shape. 
     The panel is provided with a score line  11  which is having a circular form. The score line defines the opening in the can  1 . 
     The can is opened by inserting a finger or nail beneath the rear tab part  8  in a so called gripping space  12 . Levering or tilting the tab  6  results in a popping at the front tab part  7  in the score line  11  by a movement illustrated in  FIG. 2B . 
       FIG. 2A  shows more in detail and in cross section the top panel  3  according to the invention. The top panel  3  is provided with a terrace structure  13  having three concentric terrace rings  14 - 16  at a lower position relative to the seam  5 . The terrace structure comprises a central area, which is a flip panel area  17  according to the invention. As shown in  FIG. 2A  the flip panel area  17  has a concave structure for reasons that there exists a negative pressure difference over the panel from the inside to the outside. That is, the atmospheric pressure at the outside is higher than the internal pressure at the interior  18  of the can  1  according to the invention. 
     It is noted that the downward movement of the tab  6  at its rear tab part it limited by the presence of a resting structure which has the form of a dimple  19 . 
     After popping open the panel  3  thereby forming a popping opening  20 , the pressure difference is neutralized resulting in a flipping of the flip panel area  17  from the concave form illustrated in  FIG. 2A  into the convex form illustrated in  FIG. 2B . 
     Obviously, by having a concave form as illustrated in  FIG. 2A  there is a larger and increased gripping space  12  beneath the rear tab part  8  and the panel  3  at the location of the flip panel part  17 . 
       FIGS. 3A and 3B  show an alternative of the can  21  according to the invention. The can is provided with a panel  22  having a slanted form. The panel has a central area  23  (at least beneath the rear tab part  8  of the tab  6 ), thereby forming the gripping space  12  under the rear tab part  8 . 
     The panel  23  is soldered to the body  24 . Due to the hot content of the can  21  after closure there will be an internal pressure which is lower than the atmospheric pressure and accordingly there is a negative pressure difference over the panel  22 . Due to this negative pressure difference the flip panel part  23  has a concave form. 
     Popping opens the panel  22  by levering or tilting the tab  6 , the flip panel area  23  flips over into a convex form. 
       FIGS. 4A and 4B  show another can  25  according to the invention. The top panel  26  has a central flip panel area  27  which has in cross-section a wavy shape. This wavy shape defines a depression  28  beneath the rear tab part  8  thereby forming the increased gripping space  12 . 
       FIG. 4B  shows that upon opening the can  25  with the tab  6  and after pressure equilibration over the top panel  26 , the flip panel  27  changed form such that the depression  28  is transformed in a more flat area  29 . However, the trendline  30  changed from a substantially concave into a substantially convex form. 
     FIGS.  5 A/ 5 B show another can  31  according to the invention. The can  31  has a panel  32  comprising a flip panel area which has an annular depression  34  and a central flat portion  35 . After neutralization of the negative pressure difference over the panel  32 , the flip panel area  33  changes from the form depictured in  FIG. 5A  into the form depictured in  FIG. 5B  whereby the depression  34  has disappeared and the central portion  35  moved upwardly. Again, the trendline  36  has changed from a substantially concave form into a substantially convex form. 
     The can, body and/or panel may be made of metal, such as aluminium and steel. 
     The cans may be round or non-round (oval and rectangular). When round the can may have a diameter from about 52 to 153 mm. At lower diameters, the panel having a terrace structure will have about 1 or 2 terraces but at higher diameters the number of terraces may increase. The advantage of such terrace structures is to provide stiffness in the terrace structures and to allow the best flexible flipping properties controlled and relied to the flip panel area which is generally the central panel area. 
     When made of steel the panel may have a thickness as from 0.13 to 0.30 mm. The thickness may be less in the area forming the flip panel area. 
     In the following figures are the values for the metal thickness, diameters and radii in mm. 
       FIG. 6  shows three variations of an easy opening panel according to the invention having a diameter of 73 mm or larger. Only the concave form is shown. The values for the various diameters and angles are shown in the following table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
               
                   
               
               
                 (see FIG. 6) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 metal thick 
                 r0 
                 R1 
                 r1 
                 a1 
                 R2 
                 r2 
                 a2 
               
               
                   
               
               
                 0.20 +/− 0.4 
                 100 + (flat) − 20 
                 8 +/− 4 
                 0.5 +/− 0.3 
                 6° +/− 4° 
                 22 +/− 4 
                 0.5 +/− 0.3 
                 1° − 0.5° + 3° 
               
               
                 0.20 +/− 0.4 
                 100 + (flat) − 20 
                 8 +/− 4 
                 0.5 +/− 0.3 
                 6° +/− 4° 
                 22 +/− 4 
                 0.5 +/− 0.3 
                 1° − 0.5° + 3° 
               
               
                 0.20 +/− 0.4 
                 100 + (flat) − 20 
                 8 +/− 4 
                 0.5 +/− 0.3 
                 6° +/− 4° 
                 (R5 + 0.5) +/− 0.2    
                 0.5 +/− 0.2 
                 1° − 0.5° + 3° 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 metal thick 
                 R3 
                 R4 
                 r4 
                 h4 
                 R5 
                 r5 
               
               
                   
                   
               
               
                   
                 0.20 +/− 0.4 
                 30 +/− 4 
               
               
                   
                 0.20 +/− 0.4 
                 30 +/− 4 
                 (R2 − 0.6) +/− 0.6 
                 0.6 − .4 + 2 
                 0.5 +/− .3 
               
               
                   
                 0.20 +/− 0.4 
                 30 +/− 4 
                   
                   
                   
                 21 +/− 4 
                 0.5 +/− 0.2 
               
               
                   
                   
               
               
                   
                 R1 is the diameter of the panel 
               
               
                   
                 R2 is the diameter of the flip panel area 
               
               
                   
                 R3 is the diameter of the central flip panel area 
               
               
                   
                 R4 is the diameter at the flip panel transition 
               
               
                   
                 R5 is the diameter at the flip panel transition groove 
               
               
                   
                 R6 is the diameter at the inner radius of the flip panel ring 
               
               
                   
                 r0 is the central flip panel area radius 
               
               
                   
                 r1 is the flip panel transition radius 
               
               
                   
                 r2 is the radius at the flip panel ring 
               
               
                   
                 r4 is the radius at flip panel transition 
               
               
                   
                 r5 is the radius of the transition groove 
               
               
                   
                 r6 is the inner radius of the flip panel ring 
               
               
                   
                 a1 is the angle of the flip panel ring 
               
               
                   
                 a2 is the angle of outer panel ring 
               
               
                   
                 h4 is the height of the flip panel transition 
               
               
                   
                 h6 is the height of the transition groove 
               
            
           
         
       
     
     For the configuration of  FIGS. 6A ,  6 B, and  6 C is the height difference between the concave and convex form about 4.3±1.5 mm. However, the transformation from concave to convex occurs for  FIG. 6A  at a pressure difference of 0.6±0.3 bar (−20%), for  FIG. 6B  at a pressure difference of 0.5±0.3 bar (−15%), and for  FIG. 6C  at a pressure difference of only 0.35±0.3 bar (−5%). As shown by  FIG. 6D  in top view, is the geometry due to the presence of the easy opening tab not symmetrical. Furthermore, the outer concentric area beyond R 3  forms a secondary geometry which could be rigid (flat) or flexible (wavy) which may have an additional effect on the pressure difference. 
       FIG. 7  shows another variant of the easy opening panel according to the invention. In particular, for a can having a diameter of 65 mm or larger. 
     Table 2 shows the various diameters and angles. 
                                             TABLE 2                  metal thick.   r0   R1   r1   h1   R2   r2               0.16 +/− 0.4   30 +/− 10   (R2 − 0.6) +/− 0.4   0.3 − 0.1 + 0.2   0.25 +/− 0.15   (R3 − 1.5) +/− 0.2   0.3 − 0.1 + 0.2                                                         metal thick.   R3   r3   h2   a1   R4   r4                       0.16 +/− 0.4   8.5 +/− 2   2 − 1.6 + 1   0.15 +/− 0.1   5° +/− 2°   14 − 2 + 10   1 +/− 1                       R0 is the radius of the central flip panel           R1 is the inner diameter of the central flip panel inner groove           R2 is the outer diameter of the central flip panel inner groove           R3 is the diameter of the central flip panel outer groove           R4 is the panel diameter           r0 is the radius of the central flip panel           r1 is the inner radius of the inner groove           r2 is the outer radius of the inner groove           r3 is the radius of the outer groove           h1 is the height of the inner groove           h2 is the height of the outer groove           a2 is the angle of the panel outer ring            
The height difference between the concave and convex form is about 1.0±0.5 mm, and initiated by a pressure difference of only 0.15±0.05 bar (−10%).
 
     Finally,  FIG. 8  shows another variant for a easy opening panel having a diameter of 65 mm or larger. The flex panel is shown in convex shape position and only the main geometry is represented. 
     Table 3 shows the various diameters and angles. 
     
       
         
           
               
               
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
             
            
               
                 metal thick. 
                 R1 
                 r1 
                 R2 
                 r2 
                 R3 
                 r3 
                 h1 
               
               
                   
               
               
                 0.16 +/− 0.4 
                 (R2 − 0.5) +/− 0.4 
                 0.5 − 0.1 + 0.2 
                 (R3 − 2) +/− 0.2 
                 0.5 − 0.1 + 0.2 
                 5.5 +/− 0.5 
                 10 + (flat) − 3 
                 0.25 +/− 0.15 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                 metal thick. 
                 R4 
                 r4 
                 h2 
                 R5 
                 r5 
                 a1 
                 R6 
               
               
                   
               
               
                 0.16 +/− 0.4 
                 (R3 + 1.6) +/− 0.2 
                 0.5 − 0.1 + 0.2 
                 0.15 +/− 0.15 
                 (R4 + 0.5) +/− 0.2 
                 0.5 − 0.1 + 0.2 
                 5° +/− 2° 
                 14 − 5 + 10 
               
               
                   
               
               
                 R1 is the diameter of the panel central part 
               
               
                 R2 is the diameter at the inner groove edge 
               
               
                 R3 is the diameter at the center of the groove 
               
               
                 R4 is the diameter at the outer groove edge 
               
               
                 R5 is the diameter at the outer ring transition 
               
               
                 R6 is the panel diameter 
               
               
                 r1 is the radius at the panel central part 
               
               
                 r2 is the radius at the inner groove edge 
               
               
                 r3 is the radius of the groove 
               
               
                 r4 is the radius of the outer groove edge 
               
               
                 r5 is the radius at the outer ring transition 
               
               
                 h1 is the height of the groove 
               
               
                 h2 is the height at the outer groove edge 
               
               
                 a1 is the angle of the outer ring 
               
            
           
         
       
     
     In this case, the height difference due to the concave to convex transformation was 1.0±0.5 mm as a result of a pressure difference of 0.15±0.05 bar (−10%). 
     It is noted again that the tab used may be a conventional tab. The object of the invention is to provide an improved and larger space available for the user for inserting nail and/or finger tip under the rear tab part thereby improving the gripping action and the opening of the can.