Patent Publication Number: US-2006016821-A1

Title: Packaging container with flared peripheral clearance

Description:
FIELD OF THE INVENTION  
      The present invention relates to a packaging container for foodstuff, and more particularly to a packaging container that has increased contact area between its box and cover to ensure firm closing of the cover to the box while the cover could be easily removed from the box at a flared peripheral clearance of the packaging container. The packaging container is also provided at the cover with a vent, protecting the packaging container heated in a microwave stove against deformation or bursting open.  
     BACKGROUND OF THE INVENTION  
      Living in a busy modern society, all people wish to have their food processed and packaged in a convenient be carried without easily becoming spilt. There are various kinds of fast food that require different manners of packaging. Many different designs have been developed for packaging food stuff.  FIG. 5  shows a most common conventional packaging container for foodstuff that generally includes a box and a cover. For the cover to tightly close to the box, the cover is provided along a whole periphery with a downward bent flange adapted to clamp a corresponding bent flange of the box. While such downward bent flange on the cover allows the cover to tightly close to the box, it prevents easy removal of the cover from the box once the cover is closed to the box, and thereby causes inconvenience to a user in opening the packaging container. Moreover, the packaging container tends to burst open when the periphery thereof is subjected to collision or impact. Another problem with the conventional packaging container for foodstuff is the whole container tends to deform or burst open when it is heated in a microwave stove.  
      It is therefore tried by the inventor to develop a packaging container for foodstuff that eliminates drawbacks existed in the conventional packaging containers.  
     SUMMARY OF THE INVENTION  
      A primary object of the present invention is to provide a packaging container for foodstuff that is easy to manufacture, has increased contact area between its box and cover to ensure firm closing of the cover to the box while the cover could be easily removed from the box at an outer periphery of the packaging container, and is protected against deformation or bursting open when being heated in a microwave stove.  
      To achieve the above and other objects, the packaging container of the present invention mainly includes a box having an open top and a first flange horizontally outward extended from a periphery of the open top, and a cover having a second flange horizontally outward extended from a periphery of the cover corresponding to the first flange. The first and the second flange are provided at corresponding positions with complementary recess and projection belts that fitly engage with each other to enhance connection of the cover to the box. Outer edges of the first and the second flange are bent downward and upward, respectively, to form a flared peripheral clearance between the cover and the box, allowing the cover to be easily removed from the open top of the box at the flared peripheral clearance. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein  
       FIG. 1  is an assembled sectional view of a packaging container according to a preferred embodiment of the present invention;  
       FIG. 2  is a fragmentary, enlarged sectional view of the packaging container of  FIG. 1 ;  
       FIG. 3  shows the manner of separating the cover of the packaging container of the present invention from the box thereof;  
       FIG. 4  is an assembled sectional view of a packaging container according to another embodiment of the present invention; and  
       FIG. 5  is an assembled sectional view of a conventional packaging container for foodstuff. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Please refer to  FIG. 1  that is an assembled sectional view of a packaging container according to a preferred embodiment of the present invention. As shown, the packaging container of the present invention mainly includes a box  1  and a cover  2 . The box  1  has an open top  11 , along which a horizontally outward extended first flange  12  is formed. The cover  2  has a second flange  22  horizontally outward extended from a periphery thereof for fitly closing to the open top  11  of the box  1 .  
      The packaging container of the present invention is characterized in that a continuous recess belt  31  is provided along the first flange  12  on the box  1 , and a continuous projection belt  32  is correspondingly provided along the second flange  22  on the cover  2  for fitly engaging with the recess belt  31 , and that outer edges  41 ,  42  of the first flange  12  and the second flange  22  are bent downward and upward, respectively, to form a flared peripheral clearance  5  between the box  1  and the cover  2  when the cover  2  is fitly closed to the open top  11  of the box  1 . The flared peripheral clearance  5  allows a user to easily remove the cover  2  from the open top  11  of the box  1 .  
      Please refer to  FIG. 2  that is a fragmentary and enlarged view of the packaging container of  FIG. 1  showing a detailed structure of the first and the second flange  12 ,  22 . As shown, the first flange  12  of the box  1  includes an inner belt  121  immediately extended along the open top  11  of the box  1 , a recess belt  31  located outside the inner belt  121 , an outer belt  122  located outside the recess belt  31 , and a downward bent outer edge  41 . Similarly, the second flange  22  of the cover  2  includes an inner belt  221  immediately extended along a periphery of the cover  2 , a projection belt  32  located outside the inner belt  221 , an outer belt  222  located outside the projection belt  32 , and an upward bent outer edge  42 . The special structure of the first and the second flange  12 ,  22  allows the closed box  1  and cover  2  to have an increased contact area and enhanced connecting force between them, preventing the cover  2  from easily bursting open under collision or impact. The flared peripheral clearance  5  between the opposed outer edges  41 ,  42  of the box  1  and the cover  2  extends a whole outer periphery of the packaging container, and a user may easily open the closed cover  2  from the top  11  of the box  1  at any point on the flared peripheral clearance  5 , as shown in  FIG. 3 .  
      The packaging container of the present invention is also characterized in a vent  21  provided at a predetermined position on the cover  2  and having a predetermined size. When the packaging container with foodstuff contained therein is heated in a microwave stove, thermally expanded air in the packaging container is discharged from the vent  21  to avoid undesired deformation or bursting open of the box  1  and the cover  2  of the packaging container. For packaging containers that are injection-molded from a polypropylene (PP) material, the provision of a vent on the cover is an absolutely novel design.  
       FIG. 4  shows a packaging container according to a second embodiment of the present invention. The second embodiment is generally similar to the first embodiment, except that the first flange  12  of the box  1  is provided with the projection belt  32  while the second flange  22  of the cover  2  is provided with the recess belt  31  to fitly engage with the projection belt  32 . With this structure, the cover  2  could still be firmly closed to the open top  11  of the box  1 .  
      With the above arrangements, the cover  2  and the box  1  of the packaging container of the present invention have increased contact area and enhanced connecting effect between them. Moreover, the flared peripheral clearance  5  between the outer edges  41 ,  42  of the closed box  1  and cover  2  facilitates easy removal of the cover  2  from the box  1 , and the vent  21  provided on the cover  2  effectively prevents the whole packaging container from deformation or bursting open when the packaging container is heated in a microwave stove. Therefore, the packaging container of the present invention is more practical for use.  
      The present invention has been described with some preferred embodiments thereof and it is understood that many changes and modifications in the described embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.