Patent Publication Number: US-7222745-B2

Title: Plastic boxes and methods for making same

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates generally to the field of packaging, and more particularly to advantageous aspects of an improved plastic box and methods for making same. 
   2. Description of Prior Art 
   In current designs, boxes for retail items, such as shoes, are commonly fabricated from cardboard. There are a number of reasons that cardboard is used rather than plastic. First, cardboard boxes are relatively inexpensive, yet strong enough to allow multiple boxes to be stacked on top of each other. Further, cardboard boxes are typically breathable, preventing a buildup of moisture within the box that could lead to mildew, mold, or other damage to the boxes&#39; contents. 
   However, cardboard boxes suffer from a number of disadvantages. First, cardboard boxes tend to lack esthetic appeal. Although it is possible to apply graphics and other designs to the exterior of a cardboard box, the appearance of a cardboard box is often spoilt when the box becomes even slightly worn or damaged. Also, cardboard boxes typically have unfinished or plain white interiors. One reason for this is that the use of a colored box interior carries with it the risk that the interior colors may migrate onto the contents of the box. 
   Plastic has not been a favored material for use in fabricating boxes and lids to hold certain types of retail items, such as shoes. One reason is that plastic boxes may be more expensive to manufacture than cardboard boxes. In addition, plastic boxes may lack the structural strength of a comparably sized cardboard box. Further, a plastic box may not be sufficiently breathable to prevent mildew or mold from forming on the box contents. 
   SUMMARY OF THE INVENTION 
   These and other issues are addressed by the present invention, aspects of which provide a package including a base having a substantially rectangular perimeter. A pair of side walls and a pair of end walls extend upward from the perimeter of the base to form a box bottom having rounded corners and vertices. The box bottom includes a mouth at the top thereof. The mouth has a substantially rectangular perimeter. Reinforcing ridges are formed at the corners and vertices of the box bottom, and a lip is formed at the perimeter of the mouth. A lid fits over the mouth of the box bottom. The lid includes a collar having a cuff that engages the lip to hold the lid in position over the mouth of the box bottom. At least one air hole is formed in the base of the box bottom and in the lid, and a plurality of inwardly protruding panels is formed in the lid and in the base and walls of the box bottom. 
   Additional features and advantages of the present invention will become apparent by reference to the following detailed description and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1 and 2  show perspective views of a box bottom and lid, respectively, according to a first aspect of the invention. 
       FIG. 3  shows a bottom view of a corner of the box bottom shown in  FIG. 1 . 
       FIG. 4  shows a cross section of the box bottom and lid shown in  FIGS. 1 and 2  in an open configuration. 
       FIG. 5  shows a cross section of the box bottom and lid shown in  FIGS. 1 and 2  in a closed configuration. 
       FIGS. 6 and 7  show perspective views of a box bottom and lid according to a further aspect of the invention. 
       FIGS. 8 and 9  show perspective views of a box according to a further aspect of the invention.  FIG. 8  shows the box in a closed configuration, and  FIG. 9  shows the box in an open configuration in which the lid has been positioned under the bottom exterior face of the box bottom. 
       FIGS. 10–13  show, respectively, bottom, side, end, and perspective views of a box bottom according to the present aspect of the invention. 
       FIGS. 14–17  show, respectively, top, side, end views of a lid according to the present aspect of the invention. 
       FIG. 18  shows a flowchart of a method according to a further aspect of the invention. 
   

   DETAILED DESCRIPTION 
   An aspect of the present invention provides a box bottom and lid for holding retail items, such as shoes, or the like. As described below, the box bottom and lid include structural components that allow the box bottom and the lid to be fabricated relatively inexpensively out of plastic using a thermoforming technique, while still having sufficient strength to allow numerous boxes to be stacked on top of each other. In addition, the box bottom and lid are designed so that the box they form is breathable, thus tending to prevent the box&#39;s contents from developing mold or mildew. 
   It should be noted that even apparently moisture-resistant retail items, such as athletic shoes, may retain some moisture. This moisture may be introduced into the retail items, for example, as part of the item&#39;s manufacturing process. Also, during packaging, shipment, and storage, retail items are typically subjected to a wide range of temperatures and humidities. Thus, for example, if the retail items are packaged under high humidity conditions, a certain amount of moisture may be trapped inside the box, which can subsequently lead to the development of mildew or mold during shipment or storage. 
   According to a further aspect of the invention, the box bottom and lid are fabricated from a transparent plastic material so that the box&#39;s contents are visible from the exterior of the box. The transparency of the box material serves an esthetic function, as a transparent box is typically more visually appealing than a typical cardboard box. In addition, the transparency of the box material is useful because it allows store employees and customers to view the contents of the box without having to open it. Also, a transparent box according to the invention may be tinted, if desired, to enhance its visual appeal, or to separate boxes into different styles, sizes, or other categories. For example, different shoe sizes can be color coded to avoid misshelving when items are hurriedly returned to inventory, and also to allow store employees to readily identify misshelved boxes when inventory is being checked. 
   In a typical thermoforming technique, sheets or rolls of suitable plastic material are heated and then pressed into a suitable mold. The use of a thermoforming technique is advantageous because it allows boxes and lids according to the present invention to be manufactured quickly and economically. According to an aspect of the present invention, a thermoforming technique is used to fabricate each of the box bottom and the lid as a seamless, completely formed unit. 
   It should be noted that the manufacture of a typical cardboard box is a multi-step process. In a first step, a sheet of cardboard is cut and scored to form a blank, having panels and glue flaps separated by score lines. The blank must then be folded into a box shape, and the glue flaps must then be glued into position. Thus, the use of a thermoforming technique may significantly reduce the amount of time and labor required to manufacture a box. 
   As mentioned above, thermoformed plastic boxes have typically lacked the strength and breathability required for many retail packaging applications. However, as discussed in detail below, an aspect of the present invention provides a box bottom and lid in which a thermoforming process is used to form certain structural elements in the box bottom and lid that enhance the strength and breathability of the box. Suitable materials for thermoforming include, but are not limited to, such materials as polypropylene, polyvinyl chloride (PVC) amorphous polyethylene terephalate (APET) or polyethyleneterephthalateglycolate (PETG). 
   According to a further aspect of the invention, the box bottom and lid are fabricated from sheets of plastic having different thicknesses. In particular, it has been found that a thicker material may be used for the lid than for the box bottom. The added thickness of the lid material increases the strength and durability of the lid. It would also be within the spirit of the invention, if desired, to use different materials for the box bottom and lid. The box bottoms and lids illustrated in  FIGS. 1–17  and discussed below were fabricated from PVC. It has been found that suitable thicknesses for the material were as follows:
         Four sides of the shoe box: 0.5–0.6 mm   Bottom of the shoe box: 0.4–0.5 mm   Lid of the shoe box: 0.7–0.75 mm       

     FIGS. 1 and 2  show, respectively, perspective views of a box bottom  10  and a lid  60  according to a first aspect of the invention. The box bottom  10  includes a base  12  that is substantially rectangular in shape. Extending upward from the four side edges of the base  12  are first and second side walls  14  and  16  and first and second end walls  18  and  20 . The term “wall” is used herein to refer generally to any of side walls  14  and  16  and end walls  18  and  20 . The base and four walls together form a box bottom with a substantially rectangular mouth  22  opposite the base  12 . Each of the four walls  14 ,  16 ,  18  and  20  are joined at their side edges to an adjacent wall at four corners  24 ,  26 ,  28  and  30 . The corners of the base  12  meet the bottom corners of the four walls  14 ,  16 ,  18  and  20  to form vertices  32 ,  34 ,  36 , and  38 . According to an aspect of the invention, each of the four corners  24 ,  26 ,  28  and  30  and each of the four vertices  32 ,  34 ,  36  and  38  are rounded. 
   The box bottom  10  further includes a lip  40  formed at the perimeter of the mouth  22 . The lip  40  may be formed, for example, by folding over the upper edge of the box bottom  10  during the forming process. The lip  40  serves to reinforce the mouth  22 . The lip  40  also provides a structure that can be used to hold the lid  60  in place. 
     FIG. 2  shows a perspective view of a lid  60  according to an aspect of the invention. It will be seen that the lid  60  is shaped to fit closely over the mouth  22  of the box bottom  10 . The lid includes a base  62 , and a collar  64  extending downward from the perimeter of the base  62 . The bottom edge of the collar  64  terminates in a cuff  66 . The cuff  66  is dimensioned and positioned to grip the lip  40  of the box bottom  10  when the lid  60  is placed onto the box bottom  10 . According to a further aspect of the invention, the lid  60  is fabricated from a material having a thickness that is greater than the thickness of the material used to fabricate the box bottom  10 . This extra thickness adds strength to the lid  60 , facilitating the stacking of boxes on top of each other. 
   As shown in  FIGS. 1 and 2 , the box bottom  10  and lid  60  include a plurality of air holes  42 ,  44 ,  46  and  48 . According to the present aspect of the invention, a first pair of air holes  42  and  44  is located in the base  10  and a second pair of air holes  46  and  48  is located in the lid  60 . As described below, the air holes  42 ,  44 ,  46  and  48  combine with other structural elements, described herein, to provide ventilation for the box contents without significantly detracting from the box&#39;s strength or esthetic appearance. As mentioned above, proper ventilation tends to prevent formation of mildew, mold, or other moisture-related damage to the box contents. The air holes may be formed, for example, by using a punch, or similar device, to cut holes into the box bottom  10  and lid  60  after they have been thermoformed. 
   As further shown in  FIGS. 1 and 2 , the box bottom and lid include a plurality of panels  50 ,  52  and  54  that protrude slightly into the interior of the box bottom  10  and lid  60 . The panels  50 ,  52  and  54  are formed by making suitable indentations in the box bottom  10  and lid  60  during the thermoforming process. As shown in  FIGS. 1 and 2 , the panels are located in the lid  60  and in the base  12  and side walls  14  and  16  of the box bottom  10 . 
   According to the present aspect of the invention, the end walls  18  and  20  are smooth. Thus, the contents of the box bottom  10  may be viewed, without distortion, through the end walls  18  and  20  when a transparent material is used to fabricate the box bottom  10 . Viewing the box contents through an end wall may be useful, for example, where the boxes are stacked on a shelf. In addition, the use of a smooth end wall allows a label or other printed or decorative material to be easily adhered to the end wall. In addition, it will be appreciated that a transparent box bottom  10  may be used with a translucent or opaque lid  60  or vice versa. Also, the box bottom  10  and lid  60  may be different colors or tints. 
   The panels  50 ,  52  and  54  serve a number of purposes. First, the panels  50 ,  52  and  54  serve to increase the strength of the base  12 , walls  14 ,  16 ,  18  and  20 , and lid  50 . Specifically, the presence of panels  50 ,  52  and  54  tends to prevent any of these surfaces from buckling or deforming when weight is applied to the box. In addition, it will be seen that the panels  50 ,  52  and  54  tend to lift the box&#39;s contents away from the interior surfaces of the box. Thus, the panels  50 ,  52  and  54  tend to facilitate the circulation of air and removal of moisture. In addition, the panels  50 ,  52  and  54  tend to prevent retail items from sticking or otherwise adhering to the interior surfaces of the box. 
   As further shown in  FIG. 1 , the box bottom  10  includes a plurality of supporting ridges  56  located at corners  24 ,  26 ,  28  and  30 . The box bottom  10  further includes supporting ridges  58  at the box&#39;s bottom vertices  32 ,  34 ,  36  and  38 .  FIG. 3  shows a partial bottom view of the box bottom  10  shown in  FIG. 1 , illustrating vertex supporting ridges  58   a  and  58   b  according to a further aspect of the invention. Ridge  58   a  is referred to herein as a “radial ridge” because it extends radially from the vertex  38  towards the interior of the box bottom  10 . The radial ridge  58   a  terminates at a second ridge  58   b . The second ridge  58   b  is referred to herein as a “circumferential ridge” because it extends circumferentially around the vertex  38 . The supporting ridges  56  and  58  add strength to the corners and vertices of the box bottom  10 , while not significantly detracting from the overall esthetic appearance of the box. The ridges  56  and  58  may be easily fabricated as part of the overall forming technique. The ridges  56   58  are elevated slightly towards the exterior of the box. 
   The structural components of the box bottom and lid discussed above can be better understood with reference to  FIGS. 4 and 5 , which show axial cross sections of the box bottom  10  and lid  60  shown in  FIGS. 1 and 2 , through air holes  44  and  48 . In  FIG. 4 , the box bottom  10  and lid  60  are in an open configuration. In  FIG. 5 , the box bottom  10  and lid  60  are in a closed configuration. 
     FIGS. 4 and 5  illustrate the interaction between the cuff  66  on the lid  60  and the lip  40  on the box bottom  10 . As shown in  FIGS. 4 and 5 , the cuff  66  is dimensioned such that its perimeter is slightly smaller than the perimeter of the lip  40 . Because the box bottom  10  and lid  60  are fabricated from a deformable, resilient plastic material, the cuff  66  may be slid down over the lip  40 . When the cuff  66  clears the lip  40 , the resiliency of the plastic material causes the lip  40  to engage the cuff  66 . The cuff  66  and lip  40  are dimensioned such that the lid  60  may be subsequently removed from the box bottom  10  with a reasonably small amount of effort. As shown in  FIGS. 3 and 4 , a ridge  68  may be added to the lid  60  to enhance the gripping action between the lid  60  and the lip  40 . 
   As further illustrated in  FIGS. 4 and 5 , according to a further aspect of the invention, the angle θ between the base  12  and the walls  14 ,  16 ,  18  and  20  is slightly greater than 90 degrees. This arrangement serves a number of purposes. First, it facilitates the use of a thermoforming technique to manufacture the box bottom  10 , because it allows the box bottom  10  to be easily removed from a mold. Second, this arrangement allows multiple empty box bottoms  10  to be stacked in a nesting configuration to minimize storage space. 
     FIGS. 6 and 7  show perspective views of a box bottom  110  and lid  160  according to a further aspect of the invention. As shown in  FIGS. 6 and 7 , the panels in the box bottom  110  and lid  150  have been modified to form decorative shapes. However, even modified in this manner, the panels still increase the structural strength of the box and also facilitate circulation, as discussed above. 
     FIGS. 8 and 9  show perspective views of a box  200  according to a further aspect of the invention. The box  200  includes a box bottom  210  and a lid  260 . As shown in  FIG. 9 , the lid  260  is shaped and dimensioned so that, after the lid  260  has been removed from the box bottom  210 , the lid  260  may be positioned such that its interior face  261  abuts the bottom exterior face  211  of the box bottom  210 . As described below, the box bottom  210  and lid  260  include corresponding interlocking panel indentations  252  and  254  that allow the lid  260  to be temporarily locked against the bottom face of the box bottom  210 . 
     FIGS. 10–13  show, respectively, bottom, side, end, and perspective views of a box bottom  210  according to the present aspect of the invention. As shown in  FIG. 10 , the bottom face of the box bottom  210  includes four triangular panel indentations  252 . The triangular panel indentations  252  may be suitably formed as part of a thermoforming process used to fabricate the box bottom  210 . According to the present aspect of the invention, the box bottom panels  252  are indented towards the interior of the box  200 . 
     FIGS. 14–17  show, respectively, top, side, end views of a lid  260  according to the present aspect of the invention. As shown in  FIG. 14 , the lid  260  includes four triangular panel indentations  254 . According to the present aspect of the invention, the lid panels  254  are indented towards the interior of the box  200 . 
   It will be seen that the lid panel indentations  254  correspond in position to the four triangular panel indentations  252  shown in  FIGS. 10–13 . The lid panel indentations  254  are dimensioned so that they seat snugly into the box bottom panel indentations  252 . Thus, when the lid  260  is positioned such that its interior face  261  abuts the bottom exterior face  211  of the box bottom  210 , the lid  260  may be locked into position by seating the lid panel indentations  254  into the box bottom panel indentations  252 . The lid  260  may be released from the bottom face of the box bottom  210  by simply using one&#39;s hands to pull the lid  260  free. 
   It should be noted that the panels  252  and  254 , in addition to providing the above described locking function, also serve the functions described above with respect to the panels  52  and  54  shown in  FIGS. 1 and 2 . It should be further noted that the above described locking arrangement may be modified without departing from the spirit of the invention. For example, the number and shape of the panel indentations  252  and  254  may be modified, as desired. In addition, the panels  252  and  254  may be indented towards the exterior of the box  200  rather than towards the interior. 
   The above described locking arrangement serves a number of purposes. For example, the locking arrangement prevents a lid  260  from getting separated from its box  210 . Keeping a box and lid together may be useful in certain environments, such as a shoe store, in which numerous boxes may be open at the same time. Also, locking the lid to the bottom of the box allows a box and lid to be easily transported in an open configuration. Other advantages of the locking arrangement will be apparent to a practitioner in the art. 
   The above described locking arrangement may suitably be combined with some or all of the other structural features described above. These features include, for example, the following elements shown in  FIGS. 1–3 : the cuff  66  on the lid  60 , the air holes  42 ,  44 ,  46 , and  48 , and the supporting ridges  56  and  58 . 
     FIG. 18  shows a flowchart of a method  300  for fabricating a package according to a further aspect of the present invention. In step  302 , a base is formed having a substantially rectangular perimeter. In step  304 , side walls and end walls are formed, extending upward from the perimeter of the base to form a box bottom having rounded edges and vertices and a substantially rectangular mouth. In step  306 , panels are formed in the walls and base of the box bottom. In step  308 , reinforcing ridges are formed in the edges and vertices of the box bottom. In step  310 , a lip is formed at the perimeter of the mouth. In step  312 , at least one air hole is formed in the base of the box bottom. In step  314 , a lid is formed having a collar. The collar fits over the mouth of the box bottom and includes a cuff that is dimensioned to engage the lip at the perimeter of the mouth of the box bottom. In step  316 , panels are formed in the base of the lid. In step  318 , at least one air hole is formed in the lid. As discussed above, a thermoforming technique may be used to form the box bottom and lid, and a punching technique may be used to form the air holes in the box bottom and lid. 
   It will be apparent that the above-described box bottoms and lids, and techniques for making same, may be modified without departing for the spirit of the invention. For example, the box bottom may be provided with a locking arrangement that enables the lid, once removed from the upper opening of the box bottom, to be affixed to the bottom face of the box. 
   In addition, the above-described boxes may be used to hold various types of retail items, including footwear, other types of clothing, or even foodstuffs. In addition, the above-described boxes may be sold separately for use in storing items or food. If desired, the box may be fabricated from a microwaveable material. 
   Thus, while the foregoing description includes details which will enable those skilled in the art to practice the invention, it should be recognized that the description is illustrative in nature and that many modifications and variations thereof will be apparent to those skilled in the art having the benefit of these teachings. It is accordingly intended that the invention herein be defined solely by the claims appended hereto and that the claims be interpreted as broadly as permitted by the prior art.