Patent Publication Number: US-7896159-B2

Title: Packaging container and method

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present patent application claims priority pursuant to 35 U.S.C. §119 from Japanese Patent Application No. 2008-085411, filed on Mar. 28, 2008, the contents of which are hereby incorporated by reference herein in their entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a packaging container and method, and more particularly, to a packaging container using a pallet and enclosure box to package an article for storage and transport, and a method for packaging an article in such a container. 
     2. Discussion of the Background 
     Shipping containers are used to package large electronic equipment such as printers and copiers for storage and transport. A typical design of such containers includes an upper enclosure box to enclose an article therewithin, and a lower platform or pallet having an open-sided hollow structure to accommodate tines of a forklift during handling of the container. The enclosure box is made of corrugated cardboard with the pallet formed of wood or plywood for strength and durability, while cardboard pallets are often used depending on specific applications. 
     In most such containers, the pallet and enclosure box are secured to each other to form an integrated structure which prevents shifting of packaged articles during handling of the shipping container. To provide safe and efficient packaging of articles, various methods have been proposed to reliably secure an enclosure box to a pallet in an integrated pallet container. 
     For example, one conventional packaging container secures an enclosure box onto a pallet by passing a pair of straps around the enclosure box through side openings in the hollow pallet, and tightening the straps with a buckle or fastener connecting opposite ends of each encircling strap. 
     Another conventional packaging container includes a corrugated cardboard pallet having through-holes in its sides in addition to side openings to accommodate forklift tines, and an enclosure box having corresponding through-holes on sides near the bottom edge. In this packaging container, the enclosure box is secured to the pallet by engaging attachments in the corresponding through-holes of the pallet and the enclosure box. 
     One drawback of the securing technique using fastening straps is that the need for strapping the enclosure box and pallet makes it troublesome to assemble the container, and that handling the assembled container can damage the enclosure box where concentrated stresses are applied to those corners that are in contact with the encircling straps. 
     On the other hand, the packaging container having the pallet and enclosure box secured by corresponding through-holes is relatively easy to assemble, but requires the use of cardboard pallets rather than standard wood or plywood pallets, limiting practical application of this method to pallet containers integrally made of corrugated cardboard. 
     SUMMARY OF THE INVENTION 
     Exemplary aspects of the present invention are put forward in view of the above-described circumstances, and provide a novel packaging container using a pallet and enclosure box to package an article for storage and transport. 
     Other exemplary aspects of the present invention provide a novel method for packaging an article in a container using a pallet and enclosure box for storage and transport. 
     In one exemplary embodiment, the novel packaging container includes a pallet, an enclosure box, an enclosure base, a sheet, and a set of fasteners. The pallet is substantially rectangular in plan, and carries the article thereon. The enclosure box rests on the pallet to enclose the article therewithin, and includes a top wall, first and second pairs of opposite side walls, an open bottom, and a first set of through-holes. The top wall covers a top of the article. The first and second pairs of opposite side walls extend downward from the top wall to cover sides of the article. The open bottom is defined by edges of the side walls in contact with the pallet to pass the article therethrough during assembly. The first set of through-holes are defined in the first pair of side walls adjacent to the open bottom. The enclosure base lies between the article and the pallet to hold the article within the enclosure box. The sheet extends across at least a portion of the pallet and the first pair of opposite side walls to secure the pallet to the enclosure box when fastened to the enclosure box, and includes a flat center panel, a pair of side flaps, and a second set of through-holes. The flat center panel underlies the portion of the pallet. The pair of side flaps extends from opposite sides of the center panel upward along the first pair of opposite side walls beyond the first set of through-holes. The second set of through-holes is defined in the pair of side flaps to align with the first set of through-holes. The set of fasteners is passed through the first and second sets of through-holes to fasten the sheet to the enclosure box from outside the enclosure box. 
     In one exemplary embodiment, the packaging method includes the steps of pallet provision, base provision, article placement, box placement, sheet placement, and sheet fastening. The pallet provision step provides a pallet substantially rectangular in plan. The base provision step provides an enclosure base on the pallet. The article placement places an article on the enclosure base. The box placement places an enclosure box on the pallet to enclose the article and the enclosure base therewithin. The enclosure box includes a top wall, first and second pairs of opposite side walls, an open bottom, and a first set of through-holes. The top wall covers a top of the article. The first and second pairs of opposite side walls extend downward from the top wall to cover sides of the article. The open bottom is defined by edges of the side walls in contact with the pallet to pass the article therethrough. The first set of through-holes are defined in the first pair of side walls adjacent to the open bottom. The sheet placement places a sheet across at least a portion of the pallet and the first pair of opposite side walls. The sheet includes a flat center panel, a pair of side flaps, and a second set of through-holes. The flat center panel underlies the portion of the pallet. The pair of side flaps extends from opposite sides of the center panel upward along the first pair of opposite side walls beyond the first set of through-holes. The second set of through-holes is defined in the pair of side flaps to align with the first set of through-holes. The sheet fastening step fastens the sheet to the enclosure box from outside the enclosure box to secure the pallet to the enclosure box by passing a set of fasteners through the first and second sets of through-holes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
         FIG. 1  is an assembled view schematically illustrating a packaging container according to one embodiment of this patent specification; 
         FIG. 2  is an exploded perspective views schematically illustrating the packaging container of  FIG. 1 ; 
         FIGS. 3A through 3D  are top, front, side, and bottom views, respectively, and  FIGS. 3E and 3F  are cross-sectional views taken along line E-E and line F-F, respectively, of  FIG. 3A , schematically illustrating a pallet included in the packaging container of  FIG. 1 ; 
         FIG. 4  is a plan view schematically illustrating an example of an enclosure base included in the packaging container of  FIG. 1 ; 
         FIG. 5  is a perspective view schematically illustrating the enclosure base of  FIG. 4 ; 
         FIG. 6  is a plan view schematically illustrating an example of a sheet included in the packaging container of  FIG. 1 ; 
         FIG. 7  schematically illustrates an example of a fastener for use in the packaging container of  FIG. 1 ; 
         FIGS. 8A through 8C  are cross-sectional views schematically illustrating the fastener of  FIG. 7  in use; 
         FIG. 9  is an exploded perspective view schematically illustrating a packaging container according to another embodiment of this patent specification; 
         FIG. 10  is a partially exploded perspective view schematically illustrating a packaging container according to yet another embodiment of this patent specification; and 
         FIG. 11  is a partial perspective view schematically illustrating a packaging container according to still another embodiment of this patent specification. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     In describing exemplary embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner and achieve a similar result. 
     Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, exemplary embodiments of the present patent application are described. 
       FIGS. 1 and 2  are assembled and exploded perspective views, respectively, schematically illustrating a packaging container  100  according to one embodiment of this patent specification. 
     As shown in  FIGS. 1 and 2 , the container  100  includes a pallet  110 , an open-ended enclosure box  120 , an enclosure base  130 , a sheet  140 , a set of fasteners  150 , and eight corner pads  160 , all of which are assembled into an integrated structure for packaging an article  10 , for example, a printer, for storage or transport. 
     In the container  100 , the pallet  110  is substantially rectangular in plan and lies at the bottom to place the article  10  thereon. The enclosure box  120  rests on the pallet  110  to enclose the article  10  placed on the pallet  110 , and the enclosure base  130  lies between the article  10  and the pallet  110  to hold the article  10  within the enclosure box  120 . The sheet  140  extends across a width of the pallet  110  while fastened to the enclosure box  120  with the fasteners  150 , thereby securing the pallet  110  to the enclosure box  120 . 
       FIGS. 3A through 3D  are top, front, side, and bottom views, respectively, and  FIGS. 3E and 3F  are cross-sectional views taken along line E-E and line F-F, respectively, of  FIG. 3A , schematically illustrating the pallet  110  included in the packaging container  100  of  FIGS. 1 and 2 . 
     As shown in  FIGS. 3A through 3F , the pallet  110  includes a pair of parallel stringers  111 , a pair of parallel top deckboards  112  overlying the stringers  111  with a gap  115  therebetween, a pair of parallel bottom deckboards  113  underlying the stringers  111  with a gap therebetween, all of which are made of wood or plywood. The stringers  111  extend in a transverse-direction on opposite ends of the pallet  110 , while the top and bottom deckboards  112  and  113  extend in a longitudinal direction perpendicular to the transverse direction to define an upper load-carrying surface and a lower load-bearing surface, respectively, of the pallet  110 . The pallet  110  thus forms an open-sided hollow structure with side openings  116  leading to an interior space  117  defined by the stringers  111  and the top and bottom deckboards  112  and  113 . 
     With particular reference to  FIGS. 3A ,  3 B,  3 E, and  3 F, the pallet  110  also includes a pair of spacers  114  located on opposite ends between the top deckboards  112  above the stringers  111 . Each spacer  114  is formed of wood or plywood, and has a width substantially equal to that of the adjoining stringer  111 , a length substantially equal to that of the top deck gap  115 , and a thickness substantially equal to that of the top deckboards  112 . 
     In the assembled container  100 , the pallet  110  supports the enclosed article  10  on the upper load-carrying surface, while allowing entry of forklift tines or forks into the space  117  through the side opening  116  during handling and transport by a forklift. Further, the pallet  110  can prevent dust and other contaminants from entering the enclosure box  120  with the top deck spacers  114  fitted into a space between the pallet  110  and the enclosure box  120 . 
     As will be described later, the pallet  110  may interlock with the enclosure base  130  by accommodating a portion of the enclosure base  130  in the top deck gap  115 , so as to restrict movement of the enclosure base  130  on the underlying pallet  110 . In such a configuration, forming the deck spacer  114  and the stringer  111  of a substantially equal thickness is desirable, since it prevents the spacer  114  from projecting inward beyond the edge of the stringer  111  and urging the interlocking portion of the enclosure base  130  to interfere with proper entrance of forklift tines. 
     Referring back to  FIG. 2 , the enclosure box  120  includes an open bottom  121  and a top wall  122  opposed to each other, two pairs of opposite side walls  123  and  124  extending vertically downward from the top wall  122  to define the open bottom  121  at bottom edges thereof, and four through-holes  127 , two on each side wall  123  adjacent to the open bottom  121 . The enclosure box  120  is formed of corrugated cardboard, and is sized to fit on the rectangular pallet  110  when installed to enclose the article  10  of certain dimensions. 
     During assembly, the enclosure box  120  is placed from above onto the pallet  110  carrying the article  10  covered and cushioned by the enclosure base  130  and the corner pads  160 . Thus, the article  10  together with the base  130  and the pads  160  pass through the open bottom  121  to be enclosed by the top and side walls  122 ,  123 , and  124  in the enclosure box  120 . 
     In the assembled container  100 , the enclosure box  120  has the open bottom  121  contacting the top deckboards  112  and the top deck spacers  114 , the top and side walls  122 ,  123 , and  124  surrounding the article  10 , and the through-holes  127  positioned immediately above the pallet openings  116 . 
       FIGS. 4 and 5  are plan and perspective views, respectively, schematically illustrating an example of the enclosure base  130  before and during assembly, included in the packaging container  100 . 
     As shown in  FIG. 4 , the enclosure base  130  before assembly includes a substantially rectangular center panel  131 ; a pair of side flaps  132  extending outward from a pair of opposed parallel sides of the center panel  131 ; four openings  133 , two on each side flap  132 ; a pair of tabs  135  extending outward from another pair of opposed parallel sides of the center panel  131 ; and two pairs of narrow end flaps  137  extending outward from the center panel  131  on sides of the tabs  135 . Also included are a pair of parallel fold lines  134  separating the center panel  131  from the side flaps  132 , a pair of parallel, middle fold lines  136  separating the center panel  131  from the tabs  135 , and two pairs of parallel fold lines  138  separating the center panel  131  from the end flaps  137 . Such components of the enclosure base  130  are integrally formed of a single flat blank of corrugated cardboard, and are properly sized to support the article  10  inside the open bottom  121  of the enclosure box  120  when folded and assembled into the integrated container  100 . 
     During assembly, the flat blank of the base  130  is folded upward along the fold lines  134  and  138  to raise the side flaps  132  and the end flaps  137  above the center panel  131 , and downward along the fold lines  136  to lower the end tabs  135  below the center panel  131 . The base  130  after folding is placed on the top deck of the pallet  110 , followed by placing the corner pads  160  at four corners of the center panel  131 . 
     As shown in  FIG. 5 , the enclosure base  130  thus installed has the center panel  131  overlying the top deckboards  112  with the tabs  135  inserted into the top deck gap  115  against the top deck spacers  114 , and the side and end flaps  132  and  137  raised along the sides and ends of the pallet  110  to support the corner pads  160  in place on the center panel  131 . 
     As mentioned, the tabs  135  accommodated in the top deck gap  115  forms an interlock to restrict movement of the enclosure base  130  on the underlying pallet  110 . The end tabs  135  are sized to project downward below the top deckboards  112  only a distance sufficient to stabilize the enclosure base  130 , since too large a projection into the space  117  would interfere with proper insertion of the forklift tines. 
     With additional reference to  FIGS. 1 and 2 , in the assembled container  100 , the enclosure base  130  lies between the pallet  110  and the article  10  within the enclosure box  120 . With the side and end flaps  132  and  137  properly aligning the lower corner pads  160  on the center panel  131 , the enclosure base  130  can hold the article  10  in place within the enclosure box  120 . In addition, the side flaps  132  have the flap openings  133  facing the through-holes  127  of the enclosure box  120 . These openings  133  are larger in size than the through-holes  127 , and serve to prevent the fasteners  150  from interfering with the side flaps  132  during installation. 
       FIG. 6  is a plan view schematically illustrating an example of the sheet  140  before assembly, included in the packaging container  100 . 
     As shown in  FIG. 6 , the sheet  140  includes a substantially rectangular center panel  141 , a pair of side flaps  142  extending outward from opposed parallel sides of the center panel  141 , four through-holes  143 , two on each side flap  142 , and a pair of parallel fold lines  144  separating the center panel  141  from the side flaps  142 . Such components of the sheet  140  are integrally formed of a single flat blank of corrugated cardboard. 
     During assembly, the blank of the sheet  140  is inserted through the side opening  116  into the space  117  of the pallet  110  carrying the article  10  enclosed in the enclosure box  120 . After insertion, the sheet  140  is folded upward along the fold lines  144 , so as to raise the side flaps  142  beyond the through-holes  127  of the enclosure box  120  with the through-holes  143  aligned with the through-holes  127  of the enclosure wall  123  for fastening with the fasteners  150 . 
     As shown in  FIGS. 1 and 2 , in the assembled container  100 , the sheet  140  extends across the width of the pallet  110  and the enclosure box  120 . With the side flaps  142  fastened to the enclosure walls  123 , the sheet  140  secures the pallet  110  to the enclosure box  120 . Further, the sheet  140  covers the top deck gap  115  of the pallet  110  with the center panel  140  from below for secure and safe handling with forklift tines. 
       FIG. 7  schematically illustrates an example of the fastener  150  for use in the packaging container  100 . 
     As shown in  FIG. 7 , the fastener  150  is constituted of an open-ended tubular body  151  having one open end surrounded by a flange  153 , and the other open end having a pair of angled plates  156 , each forming an “L” in cross-section and hinged to an inner wall of the tubular body  151 , and a plug  155  connected to the flange  153  via a hinge  154 , all of which are formed as a single integrated unit made of synthetic resin. Before use, the fastener  150  has the plug  155  outside the tubular body  151  so that the hinged plates  156  point their free ends in the same direction. This allows the flange-less end of the tubular body  150  to enter an opening of a particular size. Inserting the plug  155  into the tubular body  151  causes the plates  156  to turn on their respective hinges, enabling the fastener  150  to hold together walls of a certain thickness between the flange  153  and the plates  156 . 
       FIGS. 8A through 8C  are cross-sectional views schematically illustrating the fastener  150  in use to fasten the sheet  140  to the enclosure box  120 . 
     To install the fastener  150 , first, the tubular body  151  is inserted into the aligned through-holes  143  and  127  of the sheet flap  142  and the enclosure wall  123  with the plug  155  remaining outside or partially inside the tubular body  151 . The tubular body  151  is squeezed until the flange  153  comes into contact with the sheet flap  142  ( FIG. 8A ). 
     After inserting the tubular body  151 , the plug  155  is inserted into the tubular body  151  from the flanged end toward the flange-less end ( FIG. 8B ). 
     The inserted plug  155  ultimately comes into contact with the hinged plates  156  to turn them approximately 90 degrees on their respective hinges, thereby engaging the tubular body  151  in the aligned through-holes  143  and  127 . Thus, the fastener  150  connects together the sheet flap  142  and the box wall  123  by abutting the flange  153  against the sheet flap. 142  at one end, and the plates  156  against the box wall  123  at the other end ( FIG. 8C ). 
     To release the connection between the sheet flap  142  and the box wall  123 , the fastener  150  is removed by retracting the plug  155  away from the flange-less end of the tubular body  151 , returning the hinged plates  156  to their original positions, and then drawing the tubular body  151  away from the through-holes  127  and  143 . 
     Thus, the fastener  150  provides secure connection between the enclosure box  120  and the sheet  140  through operation from outside the enclosure box  120  without requiring special tools for installation and releasing. 
     Referring back to  FIG. 2 , the eight corner pads  160 , four between the enclosure base  130  and the article  10  and four between the article  10  and the box  120 , are formed of plastic foam, such as expanded polystyrene (EPS) or expanded polyethylene (EPE), and are shaped to conform to the shape of the article  10  so as to cushion and hold the article  10  at eight corners of the container  100 . 
     Specifically, the lower four pads  160  prevent horizontal displacement of the article  10 , and the upper four pads  160  prevent vertical displacement of the article  10 . Preferably, the lower pads  160  each has a protrusion on the bottom side and the enclosure base  130  has corresponding recesses at the four corners, so as to anchor each pad  160  to the enclosure base  130  by engaging the corresponding protrusion and recess, which enables more reliable positioning of the pads  160  and the cushioned article  10  on the enclosure base  130 . 
     Having described configurations of the respective elements of the packaging container  100 , the following describes procedures for packaging the article  10  in the container  100  with particular reference to  FIG. 2 . 
     First, the enclosure base  130  is placed on the top deck of the pallet  110  with the side flaps  132  folded upward along the fold lines  134 , the tabs  135  folded downward along the fold lines  136 , and the end flaps  137  folded upward along the fold lines  138 , so that the tabs  135  fit in the gap  115  against the top deck spacers  114 . 
     After positioning the enclosure base  130 , the four corner pads  160  are placed on the respective corners of the enclosure base  130 , preferably each having a protrusion on the bottom to engage with a corresponding recess formed in the enclosure base  130 . Then, the article  10  is placed on the lower pads  160 , followed by providing the additional four pads  160  on the upper corners of the article  10 . 
     With the article  10  thus positioned, the enclosure box  120  is placed on the pallet  110  from above, with the open bottom  121  allowing entry of the article  10  into the box  120  during placement. When set in place, the enclosure box  120  has the bottom edge (i.e., the lower edges of the side and end walls  123  and  124 , or the perimeter of the open bottom  121 ) resting on the top deckboards  112  and the top deck spacers  114  around the perimeter of the enclosure base  130 . 
     The top deckboards  112  and the spacers  114 , having a substantially equal height, form a substantially even, planar surface maintaining continuous contact with the box edge, which prevents damage to the box  120  by distributing loads applied thereto, allowing for stacking of multiple containers, while preventing dust and other contaminants from entering the enclosure box  120 . 
     After placing the enclosure box  120 , the sheet  140  is inserted into the space  117  through the opening  116 , followed by folding the flaps  142  upward along the fold lines  144  and bringing the center panel  141  into contact with the top deckboards  112 . The sheet  140  thus wrapping the top deck of the pallet  110  is fastened to the enclosure box  120  by engaging the fasteners  150  in the through-holes  143  and  127  aligned with each other. As mentioned earlier, the enclosure base  130  inside the enclosure box  120  does not interfere with installation of the fasteners  150  owing to the openings  133  providing clearance between the fasteners  150  and the side flaps  132 . 
     In the container  100  thus completed, the pallet  110  is securely connected to the enclosure box  120  by the sheet  140 , and to the enclosure base  130  by the interlock between the tabs  135  and the top deck gap  115 . Such secure connection effectively stabilizes the enclosed article  10  during handling of the container  100 , since the article  10  is fixed to the walls of the enclosure box  120  and the enclosure base  130  by the cushioning pads  160 . 
     The completed container  100  is ready for handling by a forklift with the pallet  110  accommodating the forklift tines in the deck space  117 . With the enclosure base  130  and the sheet  140  sandwiching the top deck gap  115 , the container  100  prevents the forklift tines from accidentally sticking into the gap  115  to damage the enclosed article  10  during handling with a forklift. 
     Further, when necessary, the container  100  allows access to the enclosed article  10  by removing the enclosure box  120  from the pallet  110  through the ready and tool-less operation of the fasteners  150  as mentioned above. 
     Thus, the packaging container  100  according to this patent specification enables secure connection between the enclosure box and pallet, which requires no modification of an existing pallet design, while providing good protection of the enclosure against breakage as well as ready and tool-less assembly and disassembly of the integrated container. 
       FIG. 9  is an exploded perspective view schematically illustrating a packaging container  200  according to another embodiment of this patent specification. 
     As shown in  FIG. 9 , the general configuration of the container  200  is similar to that depicted primarily in  FIG. 2 , except that the container  200  uses a sheet  340  with additional flaps instead of the sheet  140  of  FIG. 6 . 
     Specifically, the sheet  340  includes a substantially rectangular center panel  341 , a pair of side flaps  342 , four through-holes  343  (two each in each of side flaps  342 ), and a pair of parallel fold lines, similar to those of the sheet  140 . In addition, the sheet  340  includes a pair of flaps  347  extending from another pair of opposed parallel sides of the center panel  341 , and a pair of fold lines  346  separating the center panel  341  from the flaps  347 . 
     During assembly, the blank of the sheet  340  is folded downward along the fold lines  346 , so as to lower the end flaps  347  before insertion into the deck space  117  and subsequent folding of the side flaps  342 . The folded end flaps  347  each has a height slightly smaller than that of the space  117 , and when inserted into the space  117 , has a bottom edge resting on the bottom deckboards  113  to retain the center panel  341  immediately beneath the top deckboards  112 , which facilitates subsequent fastening of the sheet  340  to the enclosure box  120 . 
     Thus, the embodiment with the downward flap  347  enables readier installation of the sheet  340 , leading to enhanced usability of the container according to this patent specification. 
       FIG. 10  is a partially exploded perspective view schematically illustrating a packaging container  400  according to yet another embodiment of this patent specification. 
     As shown in  FIG. 10 , the general configuration of the container  400  is similar to that depicted primarily in  FIG. 2 , except that the container  400  uses a triple-stringer pallet  410  and a pair of twin sheets  440  instead of the pallet  110  and the sheet  140  of  FIG. 2 . 
     Specifically, the pallet  410  includes a middle stringer  412  in addition to a pair of end stringers  411 , thus forming a pair of separate hollow spaces  417  on opposite sides of the middle stringer  412  between the top and bottom deckboards. The triple-stringer structure provides stiffness to the pallet  410 , which is desirable particularly where the pallet has a substantial length over which to support a load of greater volume and weight. 
     In addition, the twin sheets  440  each includes a substantially rectangular, elongated center panel  441 , a pair of side flaps  442  extending from opposite ends of the center panel  441 , a pair of through-holes  443 , one on each side flap  442 , and a pair of parallel fold lines  444  separating the center panel  441  from the side flaps  443 . 
     During assembly, each twin sheet  440  is inserted into the deck space  417 , and is folded upward along the fold lines  444 , so as to raise the side flaps  442  beyond the through-holes  127  of the enclosure box  120  with the through-holes  443  aligned with the through-holes  127  of the enclosure wall  123  for fastening with the fasteners  150 . 
     Thus, the embodiment with the triple-stringer pallet  410  and the twin sheets  440  enables application of the container to packaging of heavy or bulky articles. Optionally, each twin sheet  440  may include additional downward flaps similar to those described in  FIG. 9 , which facilitates installation of the sheet  440  into the deck space  417 . 
       FIG. 11  is a partial perspective view schematically illustrating a packaging container  500  according to still another embodiment of this patent specification. 
     As shown in  FIG. 11 , the general configuration of the container  500  is similar to that depicted in  FIGS. 2 ,  9 , or  10 , except that the container  500  has a four-flap enclosure base  530  instead of the enclosure base  130  of  FIG. 5 . 
     Specifically, the enclosure base  530  includes a substantially rectangular center panel  531 , a pair of side flaps  532 , and four through-holes  533 , similar to those depicted in  FIG. 5 . In addition, the enclosure base  530  includes a pair of integral end flaps  537  extending outward from the center panel  531 , a pair of tabs  535  formed by cutting out a portion of the end flap  537 , and a pair of parallel, discontinuous fold lines  538  on sides of the tabs  535  separating the center panel  531  from the end flaps  537 . 
     The flat blank of the base  530  is folded upward along the fold lines  538  to raise the end flaps  537  above the center panel  531 . The enclosure base  530  with the integral end flap  537  requires only a single fold to form each end wall to support the lower pads  160 , whereas the enclosure base  130  with the separate end flaps requires two folds for each end wall. Thus, the embodiment of  FIG. 11  saves time in installing the enclosure base  530 , while the embodiment of  FIG. 5  makes it effortless to form each end wall of the enclosure base  130  for ready assembly of the packaging container. 
     Numerous additional modifications and variations are possible in light of the above teachings. For example, pallets used in the packaging container according to this patent specification may be made of synthetic resin, metal, or any suitable material and may have four open sides to allow entry of forklift tines from four directions, although the embodiments described herein use a two-way pallet of wood or plywood. 
     Further, although the enclosure box, the enclosure base, and the sheet described above are formed of corrugated cardboard, alternatively these components may be formed of corrugated plastic or any other suitable material, and may be suitably sized and shaped depending on the intended application. 
     Furthermore, fastening the sheet to the enclosure box may be performed by using a fastener of a mechanism and a material other than the plastic flanged-tube fastener as described herein, as long as it can connect the sheet and box walls by being inserted into aligned openings from outside the enclosure box. 
     It is therefore to be understood that, within the scope of the appended claims, the disclosure of this patent specification may be practiced otherwise than as specifically described herein.