Abstract:
A can ( 1 ) made from metal or plastic including a cap ( 5 ) with an annular sealing element ( 25 ). A sealing lip ( 29 ) is formed on the sealing element that is essentially aligned radially outwardly. The lip contacts an apex (S) of the upper rim of the container ( 3 ) when the cap ( 5 ) is put on and twisted tight. In case of an overpressure inside the can ( 1 ), gas can exit by lifting the sealing lip ( 29 ). In case of a higher exterior pressure p 0 , the sealing lip ( 29 ) is pressed with greater force against the container ( 3 ) and prevents the entry of any air.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of Swiss Patent Application no. 00345/08, filed Mar. 10, 2008, and Swiss Patent application 01649/08, filed Oct. 17, 2008, which are incorporated herein by reference as if fully set forth. 
       BACKGROUND 
       [0002]    The invention relates to a can comprising metal or plastic, and in particular to a container and a cap, which can be connected to the container in a sealing fashion and that can be resealed for a partial removal of the material in the container. 
         [0003]    It is known to seal containers with a screw-type cap in an air-tight manner. In order to achieve such tightness the cap is provided with an annular seal, usually comprising injected rubber. Such seals fulfill their purpose and the can may be opened for removing any fill material located therein and subsequently be resealed in an air-tight manner. In order to ensure the tightness of the cans even during an extended shelf life prior to the sale and/or prior to any initial opening, additionally a membrane made from aluminum may be applied in a sealing fashion over the opening of the container part. 
         [0004]    For storing products, for example smokeless tobacco, such cans are not suitable because the continued fermenting of the tobacco inside the can leads to pressure developing, which causes bulges, deformations, and/or, in the worst case scenario, an explosion of the can. A plastic deformation of the can leads to the sealing no longer being ensured and thus oxygen entering the inside, i.e. to the fill material located therein, may not be prevented. The fill material may dry out due to the oxygen entered in and, in the worst case scenario, it may spoil. 
       SUMMARY 
       [0005]    The object of the invention is to provide a can for protecting the fill material before and after the initial partial removal of fill material from any oxygen entering, however, in case of pressure developing by fermentation or an increase in volume of the air within the can due to heat, allowing an exhalation of gas from the interior of the can into the environment and after the exhalation to securely prevent oxygen from the environment from entering, even in case of a temperature-related vacuum in the can. 
         [0006]    This object is attained by a can according to the features of the invention. Advantageous embodiments of the can are described in further detail below. 
         [0007]    By using an annular sealing element with an axially effective seal and a radially outward aligned sealing lip it is possible to exhale excess pressure from the can and simultaneously also to prevent any exterior air from entering when a vacuum develops inside the can. By a suitable embodiment and sizing of the threading, the pressure of the exhalation can be adjusted. The very elastic, axially effective sealing element retains its features even after several opening and closing processes of the can. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The invention is explained in greater detail based on an illustrated exemplary embodiment. Shown are: 
           [0009]      FIG. 1  is a view of a can, with the left half being in axial cross-section, and the right half in a side view, 
           [0010]      FIG. 2  is a side view of the cap for the can, 
           [0011]      FIG. 3  is a side view of the container part, 
           [0012]      FIG. 4  is an axial partial cross-sectional view through the can with the cap being placed on it, 
           [0013]      FIG. 5  is an axial cross-sectional view through a can in an other embodiment of the invention, 
           [0014]      FIG. 6  is a side view of the can in  FIG. 5 , 
           [0015]      FIG. 7  is an enlarged view of the edge region of the can in a cross-section (indicated at A in  FIG. 5 ), 
           [0016]      FIG. 8  is an axial cross-sectional view through a can in another embodiment of the invention, 
           [0017]      FIG. 9  is a side view of the can in  FIG. 8 , and 
           [0018]      FIG. 10  is an enlarged view of the edge region of the can in a cross-section (indicated at B in  FIG. 8 .) 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0019]    In the figures, the reference character  1  marks a can. It comprises a can bottom, called container  3  for short, as well as a cap  5 . The container  3 , cylindrical in the example, is reduced in the area of its upper edge  7 , i.e. the diameter of the container  3  is smaller in the area of the upper edge  7  than in the lower section. A step  9  or a shoulder develops between the reduced area and the lower part. The upper edge of the container  3  is formed with a rolled rim  11 . This means, the edge is shared approximately oval in its cross-section by a forming process 
         [0020]    The cap  5  comprises a cap surface  13 , which covers the opening of the container  3 . A cylindrically extending collar  15  is provided on the cap  5 , in which snapping cams or threads  17  are embodied by way of plastic deformation. This free edge  10  of the collar  15  is preferably folded over to place the edge region, which may show a sharp edge by the cutting process, out of the contact area when opening the cap  5 . The snapping cams or threads  17  on the collar  15  engage the snapping protrusions or threaded sections  21  at the reduced area of the container  1  (compare  FIG. 4 .). 
         [0021]    A sealing element  25  is inserted into the circumferential bead  23  in the peripheral section of the cap surface. It comprises a support body  27 , which more or less fills the bead  25 , as well as the sealing lip  29  extending from it. The root of the sealing lip  29  is located in the area of the smallest diameter of the annularly shaped support body  27 . The free edge  31  of the sealing lip  29  is essentially aligned radially outwardly. The relaxed sealing element  25  has an axial height h 1 . The completely axially compressed sealing element  25  (not shown) has an axial height h 2 . For the axially completely compressed sealing element  25 , the sealing lip  29  contacts the support body  27 . In a cap  5 , loosely placed onto the container  1  according to  FIG. 4 , the distance between the bottom of the cap surface  13  and the apex S at the rolled rim  11  is equivalent to the height h 1  of the relaxed sealing element  5 . In this position the free edge  31  of the sealing lip  29  essentially contacts the apex S of the rolled rim  11  without any pressure. 
         [0022]    In order to close the container  3 , the cap  5  is axially pulled downward by way of turning threads, i.e. the cooperating snapping cams or threads  17  and the snapping protrusions or thread sections  21  or by an axial compression of the cap  5  over the snapping protrusions or threads  21 . Here, the sealing element  25  and/or the sealing lip  29  is pressed against the apex S of the rolled rim  11 . In order to achieve optimal sealing, the distance s between the bottom free edge  19  at the collar  15  of the cap  5  and the step  9  at the container  1  is defined such that the free edge  31  of the sealing lip  29  is pressed against the apex S with a precisely defined force. 
         [0023]    The sealing lip  29 , bent radially outwardly when viewed in the cross-section, is only axially stressed by the compression force of the cap  5  when there is no pressure difference between the atmospheric pressure p 0  and the interior pressure p 1 . A gas exchange between the interior of the can and the atmosphere does not occur. When the interior pressure is elevated, e.g., by the material filled in fermenting or by an increase in volume due to rising temperatures, gas can exit to the outside between the apex S of the rolled rim  11  at the container  3 , because the sealing lip  29  is raised by the higher pressure acting inside. An exterior pressure p 0  elevated in reference to the interior pressure p 1  however causes an increased pressure of the sealing lip  29  against the apex S, because the sealing lip  29  cannot deflect. This ensures that in case of an increased interior pressure p 1  any bulging of the cap surface  13  can be avoided. 
         [0024]    The can  1  according to the invention can be produced from metal or plastic. Combinations of a metal can  3  with a cap  5  made from plastic are also possible. 
         [0025]    The sealing element  25  can be inserted loosely into the bead  23  or be mounted thereto using an adhesive. 
         [0026]    In the embodiment of the invention according to  FIGS. 5 through 7 , the sealing element  25  is no longer inserted into the lid  5  but represents a part of the interior container  33 , which is inserted into the exterior can  1 . The interior container  33  can alternatively also comprise only an insertion part essentially shaped like a cylindrical jacket, not provided with a bottom but being supported on the bottom of the container  3  (not shown.) The sealing element  25  is embodied in the upper section of the interior container. It comprises the sealing lip  29  aligned radially outward and contacting the surface of the lid. 
         [0027]    The interior container  33  can simultaneously act as the connection between the container  3  and the lid  5 . For this purpose, an encircling groove or a recess  37  can be formed at the periphery of the interior container  33 . A first rolled bead  29  engages said recess and a second rolled bead  41  the lid  5 . 
         [0028]    In another embodiment of the invention according to  FIGS. 8 through 10  the container  3  is made from plastic. At its upper edge  43  the sealing element  25  is fastened to the sealing lip  29  by suitable means. In the example shown, in the upper edge  43 , a groove  45  is shown expanding towards the bottom, which is engaged by a respective rib  47  at the sealing element  25  and is snapped in place. By this embodiment the chance develops to produce the container  3  comprising a plastic which is harder than the plastic that the sealing element  25  is made of. Alternatively, the container  3  or the interior container  33  with the sealing element  25  are produced in a  2 K-injection molding process so that a subsequent assembly of sealing element  25  and a container  3  is omitted. 
         [0029]    In this embodiment of the invention, the lid  5  snaps in place below a bead  49  at the periphery of the container  3  made from plastic. 
       LEGEND 
       [0000]    
       
           1  can 
           3  container 
           5  cap 
           7  upper edge 
           9  step 
           11  rolled rim 
           13  cap surface 
           15  collar 
           17  snapping cams or threads 
           19  free edge 
           21  snapping protrusions or thread sections 
           23  bead 
           25  sealing element 
           27  support body 
           29  sealing lip 
           31  free edge 
           33  interior container 
           35  sealing edge 
           37  recess 
           39  first rolled bead 
           41  second rolled bead 
           43  upper edge of 3 
           45  groove 
           47  rib 
           49  bead