Abstract:
A package that comprises a bottom, a plurality of sidewalls extending away from the bottom defining an open top, each sidewall coupled to the bottom with a bottom-to-sidewall transition. The package may include a plurality of curved corner sidewalls disposed between the sidewalls and coupled to the bottom with a bottom-to-corner transition. The bottom-to-sidewall transition may comprise three sections, wherein a second section is substantially planar or slightly arced and the first and third sections being curved as necessary. The package may also include the bottom-to-corner transition comprising at least three sections, the second section being substantially planar wherein the first and third sections are curved as necessary. The second sections of both transitions may be angularly orientated to the bottom and sidewalls. The package may further include a plurality of transition elements between to couple the bottom-to-corner and bottom-to-side transitions.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 61/792,090, filed Mar. 15, 2013, the entire disclosure of which is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This present invention relates to a shape of a deep drawn thermoplastic package and a plate for deep drawing the same which improves on the prior art by equalizing the film distribution during the formation process to improve the draw ratio. 
       BACKGROUND OF THE INVENTION 
       [0003]    Deep drawn packaging has become very prevalent throughout the food packaging industries. As shown in  FIG. 8 , existing deep-drawn thermoplastic containers  400  have a substantially horizontal base  402 , four substantially vertical sidewalls  404   a ,  404   b ,  404   c  and  404   d ; four curved corner transitions  406   a ,  406   b ,  406   c , and  406   d ; and three different curved transition sections  408   a ,  408   b  and  408   c  which comprise the transition between the base  402 , the sides  404   a - d  and the corners  406   a - d . The four sidewalls define an open top  410  and a flange  412  that extends around the perimeter of open top  410 . The curved transitions  408   a - c  are incorporated into such packages due to limitations of the films materials to be formed such that walls intersect at corners. The curved transitions  408   a - c  also makes the package easier to remove from the mold. However, to maximize the volume of the packaging, the radius of curvature remains relatively small to provide a minimum reduction in the area of the bottom of the package resulting in a desired stress distribution in the packaging materials. 
         [0004]    The existing configuration performs well for shallow packaging. However, as the sidewalls are drawn deeper, the currently existing bottom-to-side curved transitions result in a non-uniform distribution of material throughout the package as the sidewalls bear a disproportionate thinning when compared to the bottom or the transition sections. Thus, there is a need in the art for a revised package shape and mold or plate particularly for deep-drawing packages which improve the material distribution throughout the package and thereby increases the overall strength of the package and lessens the risk of tears or ruptures of the packaging at the thinner portions of the packaging. 
       SUMMARY OF THE INVENTION 
       [0005]    The present application is directed toward a package, primarily for foodstuffs, that comprises a bottom and a plurality of sidewalls extending away from the bottom. The sidewalls may be connected using a plurality of curved corner sidewalls. The sidewalls and corner sidewalls may define an open top. Each sidewall may be coupled to the bottom with a bottom-to-sidewall transition. The plurality of curved corner sidewalls may be disposed between the sidewalls. One embodiment of the present package may include four sidewalls extending way from and substantially perpendicular to the bottom and four curved corner sidewalls disposed between the four sidewalls. The package may be thermoformed and/or deep-drawn and incorporated into a food packaging machine. The package may be of unitary construction. 
         [0006]    The transitions between the bottom and the sidewalls may be a bottom-to-sidewall transition that includes at least three sections. The second section may be substantially planar, wherein the first section is a curved transition between the bottom and the second section and a third section may be a curved transition between the second section and one of the sidewalls. The second section of the bottom-to-sidewall transition lies at an angle with respect to the bottom. The angle may be in a range between thirty and sixty degrees and, may more specifically be around forty-five degrees. 
         [0007]    The package may also include a bottom-to-corner transition that includes at least three sections. Similarly, the second section may be substantially planar, and the first section may be curved and provides a transition between bottom and second section. The third section may include a surface having at least two curves and provides a transition between second section and one of the curved corner sidewalls. 
         [0008]    Embodiments of the present package may further include transition elements to transition between bottom-to-sidewall transition and the bottom-to-corner transition so that the package may be leak-proof or air-proof and of a unitary construction. A first transition element provides a transition between the first section of the bottom-to-sidewall transition and the first section of the bottom-to-corner transition. A second transition element to transition between the second section of the bottom-to-sidewall transition and the second section of the bottom-to-corner transition. The package may also include a segmented transition between the third section of the bottom-to-sidewall transition and the third section of the bottom-to-corner transition. A portion of the segmented transition may be coupled to the second section of the bottom-to-corner transition. 
         [0009]    In an alternative embodiment, the package of the present invention may alternatively include the bottom-to-sidewall transition having three sections, wherein the second section is an arc of a first radius. The first section may be a curved transition between the bottom and the second section, and the first section may have a second radius. The third section may be a curved transition between the second section and one of the sidewalls wherein the third section may have a third radius. In one embodiment, the first radius is greater than both the second radius and the third radius. 
         [0010]    The present invention may also be directed toward a plate for forming the above package and/or a packaging machine that includes a plate for forming the above package. 
         [0011]    Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0012]    The accompanying drawings form a part of the specification and are to be read in conjunction therewith, in which like reference numerals are employed to indicate like or similar parts in the various views. 
           [0013]      FIG. 1  is a perspective view of a package formed in accordance with the teachings of the present disclosure; 
           [0014]      FIG. 2  is a top view of the package of  FIG. 1 ; 
           [0015]      FIG. 3  is a front view of the package of  FIG. 1 ; 
           [0016]      FIG. 4  is an end view of package of  FIG. 1 ; 
           [0017]      FIG. 5  is a section view of the package of  FIG. 2  cut along the line  5 - 5 ; 
           [0018]      FIG. 6A  is a section view of the package of  FIG. 2  cut along the line  6 - 6 ; 
           [0019]      FIG. 6B  is a section view of an alternative embodiment of the section of  FIG. 6A  in accordance with the teachings of the present disclosure; 
           [0020]      FIG. 7  is a close up perspective view of a corner of the package of  FIG. 1 ; and 
           [0021]      FIG. 8  is a perspective view of a prior art package which is improved by the present package. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    The following detailed description of the present invention references the accompanying drawing figures that illustrate specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the present invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the spirit and scope of the present invention. The present invention is defined by the appended claims and, therefore, the description is not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled. 
         [0023]    As shown in  FIG. 1 , the present packaging  10  includes a bottom  12 , a first sidewall  14 , a second sidewall  16 , a third sidewall  18 , a fourth sidewall  20 , an open top  22  defined by the sidewalls  14 ,  16 ,  18 , and  20 , and a flange  24  disposed around the perimeter of the open top  22 . 
         [0024]    First sidewall  14  includes a top  26 , a bottom  28 , a first end  30  and a second end  32 . Second sidewall  16  includes a top  34 , a bottom  36 , a first end  38  and a second end  40 . Third sidewall  18  includes a top  42 , a bottom  44 , a first end  46  and a second end  48 . Fourth sidewall  20  includes a top  50 , a bottom  52 , a first end  54  and a second end  56 . Package  10  may be any material used in the art for deep-drawing including plastic materials commonly used in the art including, known polymers, polypropylene, polyvinyl, polyester, PET, plastics, and Mylar. 
         [0025]    As further shown in  FIG. 1 , a first corner sidewall  58  joins first end  30  of first sidewall  14  and second end  40  of second sidewall  16 . The package  10  further includes a second corner sidewall  60  joining first end  38  of second sidewall  16  and second end  48  of third sidewall  18 ; a third corner sidewall  62  joining first end  46  of third sidewall  18  and second end  56  of fourth sidewall  20 ; and a fourth corner sidewall  64  joining first end  54  of fourth sidewall  20  and second end  32  of first sidewall  14 . 
         [0026]    Package  10  of the present invention also includes a multiple step transition from the base to the sidewalls that lowers the draw-ratio of the packages thereby resulting in a more uniform distribution of the packaging material. In essence, one embodiment of package  10  combines a chamfer with two fillet radius transitions to transition from bottom  12  of the package to the sidewalls  14 ,  16 ,  18 , and  20 . Similar transition structure is provided in the corners and by reducing the surface area, it subsequently reduces the amount the film must stretch in the corners and, thereby results in a thicker film. This configuration, however, reduces the total surface area of package  10  when compared to the simple fillet radius transition of the package  400  illustrated in  FIG. 8 . 
         [0027]    As shown in  FIG. 2 , a bottom-to-sidewall transition  66   a ,  66   b ,  66   c , and  66   d  comprises at least a first section  68   a - d , a second section  70   a - d , and a third section  72   a - d . Second sections  70   a - d  are one of a chord member having a linear profile or an arc length having a very large diameter and may result in a member that may appear straight or substantially planar. First sections  68   a - d  are curved transition sections that provide the transition from bottom  12  to second sections  70   a - d . Third sections  72   a - d  may also be curved transition sections that transition from second section  70   a - d  to an adjacent sidewall  14 ,  16 ,  18 , or  20 . As shown in  FIG. 2 , each first section  68   a - d  respectively includes a top side  74   a - d , a bottom side  76   a - d , a first side  78   a - d  and a second side  80   a - d . Each second section  70   a - d  respectively includes a top side  82   a - d , a bottom side  84   a - d , a first side  86   a - d  and a second side  88   a - d . In general, top side  74  of first section  68  will intersect with bottom side  84  of second section  70  and bottom side  76  of first section  68  intersects with bottom  12  at each transition. Second section  70  may be substantially planar or may include a slight arc due to a large radius. 
         [0028]    Further, each third section  72   a - d  respectively includes a top side  90   a - d , a bottom side  92   a - d , a first side  94   a - d  and a second side  96   a - d . As shown in  FIG. 2 , in general top side  82  of second section  70  intersects with bottom side  92  of third section  72  and, as shown in  FIG. 3 , top side of  90   a  of third section  72   a  intersects with the adjacent sidewall  14  for each transition. As shown in  FIG. 4 , top side  90   b  of third section  72   b  intersects with sidewall  16 . Similarly, top sides  90   c - d  of third sections  72   c - d  will intersect with sidewalls  18 , and  20  respectively. 
         [0029]    Now turning back to  FIG. 2 , the bottom-to-corner transitions  98   a ,  98   b ,  98   c , and  98   d  respectfully comprise at least a first section  100   a - d , a second section  102   a - d , and a third section  104   a - d . Each first section  100   a - d  respectively includes a top side  106   a - d , a bottom side  108   a - d , a first side  110   a - d  and a second side  112   a - d . Each second section  102   a - d  respectively includes a first inclined top side  114   a - d , a second inclined top side  116   a - d , a bottom side  118   a - d , a first side  120   a - d  and a second side  122   a - d . Generally, top side  106  of first section  100  intersects bottom side  118  of second section  102  at each respective transition as shown. Second section  102  may be substantially planar or may include a slight arc due to a large radius. 
         [0030]    Further, each third section  104   a - d  respectively includes a curved top side  124   a - d , a curved bottom side  126   a - d , a first side  128   a - d , and a second side  130   a - d . As shown in  FIG. 2 , the curved intersection of first and second inclined top sides  114  and  116  of second section  102  intersects with the curved bottom side  126  of third section  104  and, as shown in  FIG. 3 , top sides  124   a  and  124   d  of third section  104   a  and  104   d  intersect with the adjacent corner sidewalls  58  and  64  as shown. Similarly (although not shown in  FIG. 3 ), top sides  124   b  and  124   c  of third sections  104   b  and  104   c  will intersect with corner sidewalls  60  and  62  respectively. 
         [0031]      FIG. 7  demonstrates that there are a number of transition elements which are required to transition from bottom to side transitions  66   b  and  66   c  to bottom-to-corner transition  98   b . The other corners of package  10  may be identically configured and are preferably configured as such. As shown in  FIG. 7 , a first transition element  132   a  and  132   b  transitions between first portions  68   b  and  68   c  of transitions  66   b  and  66   c  with first section  100   b  of corner transition  98   b . First transition elements  132   a  and  132   b  respectively include a first side  136   a  and  136   b  and a second side  138   a  and  138   b  that respectively share a common intersection point  134   a  and  134   b . First transition elements  132   a  and  132   b  have a respective top side  140   a  and  140   b . Transition elements  132  will generally have a curved profile that varies and may transition gradually from side  136   a  proximate side  80   b  of first section  68   b  to side  138   a  proximate side  110   b  of first corner section  100   b , and also transitions gradually from side  136   b  proximate side  78   c  of first section  68   c  to side  138   b  proximate side  112   b  of first corner section  100   b.    
         [0032]    Second transition elements  142   a  and  142   b  respectively include a bottom side  144   a  and  144   b , a first side  146   a  and  146   b , and a second side  148   a  and  148   b , and a top side  150   a  and  150   b . Transition element  142  will generally have a linearly appearing profile, but the element itself will curve from second section  70   b  to side  122   b  of second corner section  102   b  and from second section  70   c  to side  120   b  of second corner section  102   b . Bottom side  144   a  and  144   b  intersect respectively with top side  140   a  and  140   b  of first section  132   a  and  132   b  as shown in  FIG. 7 . 
         [0033]    Package  10  also includes two transition elements to transition from third sections  72   b  and  72   c  to third corner section  104   b  as shown in  FIG. 7 . As such transition elements  152   a  and  154   a , and  152   b  and  154   b  create a segmented transition respectively between sections  72   b ,  72   c  and third corner section  104   b . As shown, sections  152   a  and  152   b  include respectively a bottom side  156   a  and  156   b , a first side  158   a  and  158   b , a second side  160   a  and  160   b , and a top side  162   a  and  162   b . Generally for transition element  152 , bottom side  156  intersects with top side  150  of transition element  142 . First side  158   a  intersects with side  96   b  of third transition section  72   b , and first side  158   b  intersects with side  94   c  of third transition section  72   c . Top side  162   a  intersects with bottom  36  of sidewall  16  and top side  162   b  intersects with bottom  44  of sidewall  18 . 
         [0034]    Transition element  154   a  and  154   b  include a bottom side  164   a  and  164   b , a first side  166   a  and  166   b , a second side  168   a  and  b , and a top side  170   a  and  170   b . Bottom side  164   a  of transition element  154   a  intersects second top inclined side  116   b  of second corner section  102   b . Bottom side  164   b  of transition element  154   b  intersects first inclined side  114   b  of second corner section  102   b . First side  166   a  and  166   b  respectively intersect with second sides  160   a  and  160   b  of transition elements  142   a  and  142   b . Second side  168   a  of transition element  154   a  intersects with side  130   b  of third corner section  104   b . Second side  168   b  of transition element  154   b  intersects with side  128   b  of third corner section  104   b . Top side  170   a  of transition element  154   a  intersects with a portion of bottom  36  of sidewall  16  and a portion bottom  124   b  of corner sidewall  60 . Similarly, top side  170   b  of transition element  154   b  intersects with a portion of bottom  44  of sidewall  18  and a portion of bottom  124   b  of corner sidewall  60 . The profile of transition elements  154   a  and  154   b  have a curved profile and transition elements  152   a  and  152   b  have a wedge-like shape to accommodate the differences in the surface planes between the sidewall transitions  66  and the corner transitions  98 . 
         [0035]    Now turning to  FIG. 5 , corner transition  98   b  includes second corner section  102   b  being orientated at an angle α with respect to bottom  12 . Angle α may be in a range between thirty (30) and sixty (60) degrees, but is preferably around forty-five (45) degrees. First corner section  100   b  is curved to transition between bottom  12  and second corner section  102   b . Third corner section  104   b  also curves to transition between corner sidewall  60  and second corner section  102   b . In one embodiment, second corner section  102   b  is substantially linear and constitutes a chord member that is tangential to both first corner section  100   b  and third corner section  104   b . The profile of bottom-to-corner transition  98   b  compared with a typical single-element radius transition  408   c  (shown in broken lines) having a radius R is shown. In another embodiment, second corner section may be non-tangential similar to the embodiment described below and shown in  FIG. 6B . The transition  104   b  from corner section  102   b  to corner  60  may further include a shelf  200  which may provide some lateral stability to the package  10  or may serve other utilitarian or aesthetic purpose. 
         [0036]    Now turning to  FIG. 6A , bottom-to-side transition  66   c  includes second section  70   c  being orientated at an angle β with respect to bottom  12 . Angle β may be in a range between thirty (30) and sixty (60) degrees, but is preferably around forty-five (45) degrees. First section  68   c  is curved to transition between bottom  12  and second section  70   c . Third corner section  72   c  also curves to transition between sidewall  18  and second section  70   c . In one embodiment, second section  70   c  is substantially linear and constitutes a chord member that is tangential to one or both of first section  68   c  and third section  72   c . The profile of bottom-to-side transition  66   c  compared with a typical single-element radius transition  408   a  (shown in broken lines) having a radius R is shown. The transition  72   c  from corner section  70   c  to side  18  may further include shelf  200  which may provide some lateral stability to the package  10  or may serve other utilitarian or aesthetic purpose. 
         [0037]      FIG. 6B  illustrates an alternative embodiment packaging  10 ′, which includes an alternative transition configuration than that shown in  FIG. 6A  and described above.  FIG. 6B  illustrates a non-tangential configuration of a bottom-to-side transition. In this embodiment, second section  70  is an arc length of a circle having a very large radius, and first section  68  and third section  72  may be curved at a lesser radius. As such, second section  70  will have a more abrupt transition with first section  68  and third section  72  in which a slight corner is formed, rather than a smooth curve associated with the tangential configuration shown in  FIG. 6A . Similarly, the proposed three-stage non-tangential bottom-to-side transition is shown in comparison to a typical prior art single element curved transition  408   a  formed at a radius R. 
         [0038]    Now that the shape of the package formed by a packaging mold or plate has been described, a person in the art will appreciate forming a mold or a plate which results in a package of the above configuration. The angled and/or substantially planar second sections  70  and  102  of the package of the present disclosure provide an advantage when deep drawing the packaging to distribute material more uniformly throughout the package and, thus, avoiding weak or thin portions of the sidewall. 
         [0039]    As is evident from the foregoing description, certain aspects of the present invention are not limited to the particular details of the examples illustrated herein. It is therefore contemplated that other modifications and applications using other similar or related features or techniques will occur to those skilled in the art. It is accordingly intended that all such modifications, variations, and other uses and applications which do not depart from the spirit and scope of the present invention are deemed to be covered by the present invention. 
         [0040]    Other aspects, objects, and advantages of the present invention can be obtained from a study of the drawings, the disclosures, and the appended claims.