Abstract:
Rugged stackable merchandise tray containers are provided with right-angled mounting tabs at the inner corners of the top panel of two load supporting casing formed at the two ends of the tray container. The right-angled mounting tabs are engageable with rectangular mounting openings formed at the bottom of the bottom panel when two tray containers are stacked one on top of another. The mounting provide resistance to accidental external impact exerted to the stack. At least one trapezoidal shape pull-out tabs are also provided at the edge portion of the bottom panel, which are engageable with aligned mounting slots formed at the top panel of the load supporting casings to provide further securement of the stacked tray containers as well as enhanced resistance to external impact to the stack.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to merchandise containers for transporting, storing and display merchandise, and particularly to tray containers which can be stacked together securely to withstand accidental external impact. 
         [0003]    2. Background Art 
         [0004]    Containers made of corrugated board or cardboard are commonly employed for transporting and for storage of merchandise. However, most containers are not suitable for displaying the merchandise at the sale or retail location, since the merchandise is not readily accessible from the container by customers for selecting the items to purchase. Accordingly, the merchandise, after transported to the sale or retail location, must be unpacked from the containers and be transferred to display shelves, stands, or show cases in order that customers may select the items to purchase. This procedure is time consuming and labor intensive to carry out. 
         [0005]    Containers can be made in the form of trays which can be employed for the same purposes for storage and transport as well as for displaying the merchandise readily at the retail destination so as to reduce the amount of time required for handling and re-arranging of the merchandise at the retail location. A plurality of trays can be stacked in a transporting vehicle during transport or in the warehouse during storage in order to utilize the available space efficiently. Thus, special construction must be provided in the tray to ensure that a plurality of it can be securely stacked together and withstand accidental external impact thereto. Some trays are provided with upstanding tabs at the outer corners of the top of the tray which are aligned with bottom slots formed at the bottom panel of the tray, so that a plurality of trays can be stacked together securely with the upstanding tabs of the bottom tray engaging with the aligned bottom slots of the tray at the top. Also, right-angled corners may be formed at the outer corners of the side panels of the tray so that trays can be stacked together with the upstanding right-angled corners of the tray at the bottom engaging with lower corner recesses formed in the bottom portion of the side panel of the tray at the top for holding the trays together. 
         [0006]    In known tray containers, such as that shown in U.S. Pat. No. 5,330,094 issued on Jul. 19, 1994 to Noel J. Mertz, four right-angled upstanding corners which are small in dimensions, short in height, and complex and yet unreliable in construction are provided at the upper edge of an outer cover panel of the side panels of the tray with the securement provided at the outer surface of the side panels. When two tray are stacked together, the upstanding right-angled upstanding corners of the tray at the bottom engage with the bottom corner recesses of the outer cover panels of the tray at the top to retain the trays stacked together. However, due to the small dimensions and the unprotected upstanding right-angled corners, the upstanding right-angled corners are readily deformed or mutilated during stacking of the trays or they are destroyed by impact during moving of the stack in handling or in transportation. Furthermore, the upstanding right-angled corners are an extension portion of the upper edge of the outer cover panels, and the cover panels are secured to the outer surface of the side walls of the tray with tabs inserting into slots formed in the outer surface of the side walls of the tray. When the stack of the trays is subject to accidental lateral impact it would cause the merchandise in the tray to shift due to the inherent inertia force. The force due to the shifting weight of the merchandise contained therein as well as from the external impact with other objects particularly during handling and transportation, the force would invariably exert a lateral pushing force at the right-angled corners. As the right-angled corners are part of the extensions folded over the side walls, the pushing force would cause the securement tabs of the covering panels to disengage from the side walls of the tray, thus resulting in the loss of securement between the stacked trays. Moreover, the folded extension portions cover over the outer surface of the side walls of the tray such that the side walls may not be provided with graphic matters for merchandising purposes. 
       SUMMARY OF THE INVENTION 
       [0007]    It is a principal object of the present invention to provide a tray container for the storage, transportation, as well as display purposes of merchandise without having to rearrange the merchandise at the retail location. 
         [0008]    It is an object of the present invention to provide a tray container having interlocking tabs and an associate mounting openings such that a plurality of it may be securely stacked together without being dislodged or destroyed by external forces during handling and transportation. 
         [0009]    It is another object of the present invention to provide a tray container having a relatively simple construction and may be easily assembled by forming a unique configuration on a standard size cardboard stock or the like with minimal wastage of the cardboard stock. 
         [0010]    It is another object of the present invention to provide a tray container having a rugged construction. 
         [0011]    It is yet another object of the present invention to provide a tray container having completely flat outer side walls suitable for providing graphic matter thereon for merchandising purposes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Other objects of the invention will become apparent in the following description and appended claims, reference being made in the following accompanying drawing forming a part of the specification: 
           [0013]      FIG. 1  is a front and top perspective elevation view of the tray container of the present invention. 
           [0014]      FIG. 2  is a front and bottom perspective elevation view of the tray container according to the present invention. 
           [0015]      FIG. 3  is a top perspective elevation view showing the geometrical figure formed on a single cardboard stock for fabricating the tray container of the present invention. 
           [0016]      FIG. 4  is a top and front perspective elevation view showing partial assembly of the right side of the figuration of  FIG. 3  to form the right casing of the tray container. 
           [0017]      FIG. 5  is a front and top perspective elevation view showing further partial assembly of the right casing. 
           [0018]      FIG. 6  is a front and top perspective elevation view showing the stacking of two tray containers of the present invention together. 
           [0019]      FIG. 7  is a front and top perspective elevation view showing a plurality of tray containers stacked together. 
           [0020]      FIG. 8  is a front and top perspective elevation view of a second embodiment of the tray container according to the present invention having and open front and a closed rear. 
           [0021]      FIG. 9  is a front and bottom perspective elevation view of the second embodiment of the tray container according to the present invention. 
           [0022]      FIG. 10  is a top perspective elevation of the geometrical figure provided on a single cardboard stock which is foldable to form the second embodiment of the tray container of the present invention. 
           [0023]      FIG. 11  is a front and top perspective elevation view of the second embodiment of the tray container according to the present invention with the right side of the geometrical figure partially assembled to form the right casing of the tray container. 
           [0024]      FIG. 12  is a front and top perspective elevation view showing the stacking of two tray containers of the second embodiment together. 
           [0025]      FIG. 13  is a front and top perspective elevation view of a plurality of the tray container of the second embodiment stacked together according to the present invention. 
           [0026]      FIG. 14  is a bottom and front perspective elevation view showing the alternative formation of two trapezoidal mounting tabs at the bottom edges of the tray container of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    With reference to the drawings in which like reference numerals designate corresponding parts in the different views, the tray container  10  according to the present invention has a generally lateral U shape with a rectangular bottom panel  11 . A rectangular front panel  12  having a low height extends upwards from the front edge of the bottom panel  11 , and an equally low height rectangular rear panel  13  extends upwards from the rear edge of the bottom panel  11 . The low height front and rear panels  12  and  13  facilitate easy visibility and access to and the merchandise located in the tray container from either the front or rear thereof. A generally rectangular weight supporting and reinforcement left casing  14  is located vertically upwards from the left side edge portion of the bottom panel  11 , and an equal rectangular weight supporting and reinforcement right casing  15  is located vertically upwards from the right side edge portion of the bottom panel  11 . The left casing  14  has a completely flat outer panel which forms the left outer side panel  16  of the tray container. Similarly, the right casing  15  also has a completely flat outer panel which forms the right outer side panel of the tray container. The left casing  14  has an inner panel which forms the inner left side panel  17  of the tray container. The tray container  10  may be fabricated with a geometric figure as best shown in  FIG. 3  provided on a single sheet material such as a cardboard or corrugated board stock. The geometric figure can be stamped or cut from the sheet material and assembled to form the tray container  10 . As shown in  FIG. 3 , the left outer side panel  16  has a generally L-shaped front extension panel  18  and a similar generally L-shaped rear extension panel  19  which are foldable relative to the front edge  20  and rear edge  21  respectively of the left outer side panel  16 . The L-shaped front extension panel  18  has a shorter arm portion  22  and a longer arm portion  23  perpendicular to one another with the longer arm portion  23  located adjacent to the front edge  20  of the left outer side panel  16 . The L-shaped rear extension panel  19  has a shorter arm  24  and a longer arm portion  25  perpendicular to one another with the longer arm portion  25  located adjacent to the rear edge  21  of the left outer side panel  16 . Similarly, the right casing  15  has an outer panel which forms the right outside side panel  26  of the tray container  10  and it also has a completely rectangular flat surface. The right casing  15  has an inner panel which forms the inner right side panel  27  of the tray container. The right outer side panel  26  has a generally L-shaped front extension panel  28  and a similar generally L-shaped rear extension panel  29  which are foldable relative to the front edge  30  and rear edge  31  respectively of the right outer side panel  26 . The L-shaped front extension panel  28  has a shorter arm portion  32  and a longer arm portion  33  perpendicular to one another with the longer arm portion  33  located adjacent to the front edge  30  of the right outer side panel  26 . The L-shaped rear extension panel  29  has a shorter arm portion  34  and a longer arm portion  35  perpendicular to one another with the longer arm portion  35  located adjacent to the rear edge  31  of the right outer side panel  26 . 
         [0028]    The left casing  14  has a top panel  36  formed by a generally trapezoidal shaped panel located between the left outer side panel  16  and left inner side panel  17  and it is foldable relative to the outer left side panel  16  along a common edge  37 , and foldable relative to the inner left side panel  17  along a common edge  38 . The corner edge portions  39  and  40  of the common edge  38  extend a short distance into the top panel  36 . Two narrow outer panels  41  and  42  extend outwards from the outer edges  43  and  44  of the left inner side panel  17 . The height of the narrow outer panels  41  and  42  is equal to the height of the longer arm portions  25  and  23  of the L-shaped extension panels  18  and  19 . When the left inner side panel  17  is folded along the common edge  38  to lie perpendicular to the top panel  38  after the narrow outer panels  41  and  42  having been folded to lie perpendicular to the left inner panel  17 , two right-angled mounting tabs are variably formed by the corner portions  39 ,  40  extending upward at the inner corners of the left casing  14  adjacent to the interior of the tray container as best shown in  FIG. 1 . 
         [0029]    Similarly, the right casing  15  has a top panel  45  formed by a generally trapezoidal shaped panel located between the right outer side panel  26  and the right inner side panel  27  and it is foldable relative to the outer right side panel  26  along a common edge  46  and foldable relative to the inner right side panel  27  along a common edge  47 . The corner edge portions  48  and  49  of the common edge  47  extend a short distance into the top panel  45 . Two narrow outer panels  50  and  51  extend outwards from the outer edges  52  and  53  of the right inner side panel  27 . The height of the narrow outer panels  50  and  51  is equal to the height of the longer arm portions  33  and  35  of the L-shaped extension panels  28  and  29 . When the right inner side panel  27  is folded along the common edge  47  to lie perpendicular to the top panel  45  after the narrow outer panels  50  and  51  having been folded to lie perpendicular to the right inner panel  27 , two right-angled mounting tabs are formed invariably by the corner portion  48  and  49 , extending upward at the inner corners of the right casing  15  adjacent to the interior of the tray container as best shown in  FIG. 1 . 
         [0030]    Two rectangular cover panels  54  and  55  extend outward from the outer side edges of the longer arm portions  23  and  25  of the left L-shaped extension panels  18  and  19 ; and two securing tabs  56  and  57  are formed at the outer edges of the rectangular cover panels  54  and  55  respectively. Similarly, two rectangular cover panels  58  and  59  extend outward from the outer side edges of the longer arm portions  33  and  35  of the right L-shaped extension panels  28  and  29 ; and two securing tabs  60  and  61  are formed at the outer edges of the two rectangular cover panels  58  and  59  respectively. 
         [0031]    Two rectangular retaining arms  62  and  63  are formed at the outer edge portion of the narrow outer panels  41  and  42 , of the left inner panel  17 , and extending outward from the outer corners thereof. Similarly two rectangular retaining arms  64  and  65  are formed at the outer edge portion of the narrow outer panels  50  and  51 , of the right inner panel, and extending outward from the outer corners thereof. 
         [0032]    An abutment strip  66  is formed at the outer edge of the left inner side panel  17  and similarly an abutment strip  67  is formed at the outer edge of the right inner side panel  27 . 
         [0033]    Two mounting slots  68  and  69  parallel to the side edges  43  and  44  and spaced therefrom at a distance equal to the height of the rectangular cover panels  54  and  55  respectively are formed in the left inner side panel  17 . The length of the mounting slots  68  and  69  is equal to the length of the securing tabs  56  and  57  respectively. Similarly, two mounting slots  70  and  71  parallel to the side edges  52  and  53  and spaced therefrom at a distance equal to the height of the rectangular cover panels  58  and  59  respectively are formed in the right inner side panel  27 . 
         [0034]    Two spaced T-shaped slots  72  and  73  are formed at the common edge  38  between the narrow top panel  36  and the left inner side panel  17 . The T-shaped slots  72  and  73  have slot arms  74  and  75  respectively extending into the left inner side panel  17 . Similarly, two spaced T-shaped slots  76  and  77  are formed at the common edge  47  between the narrow top panel  45  and the right inner side panel  27 . The T-shaped slots  76  and  77  have perpendicular slot arms  78  and  79  respectively extending into the right inner side panel  27 . The T-shaped slots  72  and  73  of the left casing are located directly opposite to the T-shaped slots  76  and  77  of the right casing respectively of the tray container. 
         [0035]    Two trapezoidal shaped pull-out mounting tabs  80  and  81  are formed preferably at the middle portion of the side edges  81  and  82  of the bottom panel  11 . Two arcuate openings  83  and  84  are formed adjacent to the top edge of the trapezoidal shaped push-out mounting tabs  79  and  80  respectively to facilitate the pulling of the trapezoidal mounting tabs  79  and  80  downwards out from the bottom panel  11 . Four right angled cut-outs  85 ,  86 ,  87  and  88  are formed at the four corners of the bottom panel  11 . These right angled cut-outs have dimensions equal to the dimensions of the right angled mounting tabs formed at the inner corners of the top panels  36  and  45  of the left and right support casings. 
         [0036]    Two rectangular longitudinal side panels  89  and  90  extending outwards from the longitudinal side edges  91  and  92  respectively of the bottom panel  11 ; and two longitudinal outer side panels  93  and  94  extending outwards from double foldable edges  95  and  96  of the longitudinal side panels  89  and  90  respectively. The rectangular longitudinal side panels  89  and  90  and the longitudinal outer side panels  93  and  94  have the same height. Two spaced engagement slots  97  and  98  are formed at the middle portion of the edge portion of the bottom panel  11 , and two spaced engagement slots  99  and  100  are formed at the middle portion of the edge portion of the bottom panel  11 . Two spaced engagement tabs  101  and  102  are formed at the outer edge of the longitudinal outer side panel  93  and two spaced engagement tabs  103  and  104  are formed at the outer edge of the longitudinal outer side panel  94  respectively. The engagement tabs  101  and  102  are for engagement with the engagement slots  98  and  97  for retaining the outer side panel  93  in a double folded position along the double fold edge  95  to lie juxtaposed to the longitudinal side panel  90  to form a reinforced double layer horizontal front panel  12  of the tray container, while the engagement tabs  103  and  104  are for engagement with the engagement slots  99  and  100  for retaining the outer side panel  94  in a double folded position along double fold line  96  to lie juxtaposed to the longitudinal side panel  89  to form the reinforced double layer horizontal rear panel  13  of the tray container. 
         [0037]    A mounting slot  105  is formed at the middle portion of the edge  29  of the narrow left top panel  28 , similarly a mounting slot  106  is formed at the middle portion of the edge  46  of the narrow right top panel  45 . These mounting slots have a length equal to the longer side edge of the trapezoidal mounting tabs  79  and  80 . 
         [0038]    Since the components of the left casing  14  are same as those of the right casing  15  as described above, for simplicity of description, the assembly of the right casing  15  is described below. The assembly of the corresponding components to form the left casing  14  can be carried out in the same manner so as to form the entire tray container. 
         [0039]    The right casing  15  is formed in the following sequential manner. First, the abutment strip  67  and the two retaining arms  64  and  65  are bent and folded upward along the fold lines between it and the two narrow outer panels  50  and  51  are bent and folded upward to lie perpendicular to the inner side panel  27 . The inner side panel  27  is then folded upwards relative to the fold line  47  to lie perpendicular to the top panel  45 . The top panel  45  is folded upwards until the inner side panel  27  lies over the outer side panel  26  to form the initial form of the right casing  15 . The entire initial right casing thus formed above is folded and flipped to the vertical upward position as shown in  FIG. 4  with the bent abutment strip  67  abutting the side edge portion of the bottom panel  11  and the completely flat right outer surface  26  of the outer side panel  26  now forming the outer side panel of the tray container and the inner side panel  27  now forming the inner side panel of the tray container. The two right-angled mounting tabs  107  and  108  will now extend upwards from the two inner corners of the top panel  45  of the right casing  15 . The retaining arms  64  and  65  are bent and folded to lie over the corner edge portion of the edge  91  of the bottom panel  11  and the two narrow outer panels  50  and  51  forming the vertical side edges of the right casing  15  as partially shown in  FIG. 4 . The L-shaped extension panels  28  and  29  are then folded with their longer arm portions  33  and  35  lying juxtaposed with the vertical side edges of the casing  15  to form a double reinforced layer of the right vertical side portion  109  of the front panel of the tray container  10 . The shorter arm portions  29  and  32  will now lie also at the corner edge portion of the edge  92  and  91  respectively of the bottom panel  11  to lie juxtaposed to the retaining arms  65  and  64  respectively. The cover panels  58  and  59  are then folded to lie juxtaposed to the inner side panel  29  with the securing tabs  60  and  61  bent and inserted into the mounting slots  70  and  71  to secure them firmly in the mounted position with the L-shaped extension panels  28  and  29  and the cover panels  58  and  59  wrapping tightly around the vertical side panels and edge portion of the inner side panel of the casing  15  to reinforced the rigidity of the upstanding right angled mounting tabs  107  and  108  as best shown in  FIG. 5 . The short portion  32  of the L-shaped front panel  28  together with the securement arm  64  are tightly sandwiched within the right edge portion of the double folded from panel  12  of the tray container. Two rectangular bottom mounting openings  110  and  111  are inherently formed at the bottom panel  11  with the formation of the right casing  15 . When two tray containers are stacked one on top of the other, these bottom mounting openings  110  and  111  of the tray container located on top will engage snugly with the upstanding right angled mounting tabs  107  and  108  of the tray container located at the bottom of the stack. 
         [0040]    The left casing  14  may be assembled in the same manner as the right casing  15  having all the similar components to the right casing as described above to form the complete tray container of the present invention. Two rectangular bottom mounting openings  112  and  113  are inherently formed at the left corners of the bottom panel  11  with the formation of the right casing  14 , and two right angled upstanding mounting tabs  114  and  115  formed at the inner corners of the top panel  36  of the left casing  14 . The mounting openings  110 ,  111 ,  112  and  113  have dimensions equal to the right angled mounting tabs  107 ,  108 ,  114  and  115 . 
         [0041]    Two openings  116  and  117  are formed in the left inner side panel  17  and two openings  118  and  119  are also formed in the right inner side panel  27  to facilitate the assembly of the left casing  14  and the right casing  15  with fingers inserted into these openings. 
         [0042]    Two tray containers  10  of the present invention may be mounted in a stack manner as best shown in  FIG. 6  with the right-angled upstanding mounting tabs  107 . 108 , 114 , and  114  of the tray container at the bottom engaging snugly with the rectangular openings  110 ,  111 ,  112  and  113  at the bottom of the bottom panel of the tray container at the top. With the location of the right-angled mounting tabs  107 ,  108 ,  114  and  115  at the inner corners of the bottom tray container as well as the reinforcement of the cover panels, the stack can withstand a high external from and side impacts without deforming the right-angled mounting tabs or to cause dislodgement of the securement between the stacked tray containers, because the external impact would urge the cover panels more tightly against the inner panels. 
         [0043]    As shown in  FIG. 6 , the trapezoidal pull-out mounting tabs  83  and  84  at the bottom panel of the tray container at the top may also be pulled out and inserted into the mounting slots  120  and  121  formed at the top panels  36  and  45  of the tray container at the bottom to provide additional securement between the two tray containers stacked together and to withstand high external lateral impacts to the stack. 
         [0044]    Longitudinal partitions may be provided in the tray container for dividing the interior space of the containers into separate front and rear compartments or areas to separate two different merchandise items which are separately accessible from the open front or the rear of the tray container. The partitions are provided with end hooks at their upper corners for slidably inserting into the slots  74 ,  78  and slots  75 ,  79  located at directly opposite positions of the left casing  14  and right casing  15  respectively to be securely mounted in place. 
         [0045]    A second embodiment of the tray container of the present invention is shown in  FIGS. 8 through 13 . The tray container  122  of the second embodiment has a closed rear panel. It can be fabricated with the geometrical figure as shown in  FIG. 10  provided on a single cardboard or corrugated board stock similar to that of  FIG. 3 . For simplicity of description, only the differences in construction between the two embodiments, namely the different rear panel, is described below. A rectangular rear panel  123  having dimensions for covering the entire rear side of the tray container  122  including the rear side panel of the left and right casings is provided. The rear panel  123  extends rearward from the upper edge  124  of the rectangular bottom panel  125  and it is foldable relative to the bottom panel  125  along the edge  124 . Two side mounting tabs  126  and  127  are formed at the middle portion of the side edges  128  and  129  of the rear panel  123 . A reinforcing rectangular panel  130  extends outwards from an upper double fold edge  131  of the rear panel  123 . Two side securement tabs  132  and  133  are formed at the upper edge portion of the side edges of the reinforcing rectangular panel  130 . A left rear covering panel  134  and right rear covering panel  135  having a width equal to the height of the rear panel  123  extend outward from an upper edge  136  and  137  respectively of the left outer panel  138  and right outer panel  139 . The left rear covering panel  134  is foldable along edge  136  relative to the left outer panel  138  and the right covering panel  135  is foldable along edge  137  relative to the right outer panel  139 . A hook portion  140  is formed at the upper left side of the left rear covering panel  134  with an open end slot  141  formed therein adjacent to the upper edge of the left rear covering panel  134 . A hook portion  142  is formed at the upper left side of the left rear covering panel  135  with an open end slot  143  formed therein adjacent to the left upper edge of the right rear covering panel  135 . Two mounting slots  144  and  145  are formed respectively in the left rear covering panel  134  and right rear covering panel  135  at the middle of the edges  136  and  137  respectively. The mounting slots  144  and  145  have a length equal to the length of the mounting tabs  126  and  127  respectively. A securement slot  146  is formed in the left covering panel  134  and located at the right corner therein at a short distance from the edge  136 . A securement slot  147  is formed in the right covering panel  135  and located at the left corner therein at a short distance from the edge  137 . The securement slots  146  and  147  have a length equal to the length of the securement tabs  132  and  133  respectively. 
         [0046]    The tray container of the second embodiment may be assembled in the following steps. The components of the left and right casings  148  and  149  are similar to those of the left and right casing  14  and  15  of the above embodiment are folded in the same manner. Then, the covering panels  134  and  135  are folded upward along edges  136  and  137  of the left and right outer panels  138  and  139  respectively to abut the rear panels  150  and  151  of the left and right casings  148  and  149 . The partially assembled left and right casings are then bent and flipped to the position perpendicular to the bottom panel  125  similar to that in the above embodiment, while slidably engaging the hook portions  140  and  142  of the covering panels  134  and  135  together to maintain the left and right casings firmly positioned in the vertical manner at the two side edge portions of the bottom panel  125  as partially shown in  FIG. 11 . The rear panel  123  will be folded upwards to lie in abutment with the rear surface of the now secured together covering panels  134  and  135  to form the closed rear side of the tray container. The rear panel  123  is secured firmly in the vertical position with the side mounting tabs  126  and  127  folded forward and inserted into the mounting slots  144  and  145  respectively. The reinforcing rectangular panel  130  can now be folded forward along the double fold edge  131  to lie juxtapose to the upper portion of the covering panels  134  and  135  with the side mounting tabs  132  and  133  inserted into the mounting slots  146  and  147  respectively of the covering panels  134  and  135 . Thus, the second embodiment of the tray container is formed having left casing  148  and a right casing  149  with top panels  150  and  151  respectively therein; upstanding right angled mounting tabs  152 ,  153 ,  154 , and  155  extending upward at the inner corners of the top panels  150  and  151  and located adjacent to the interior of the tray container. The outer surface of the outer panel of the left casing  148  forms the completely flat outer surface  156  of outer side panel the tray container; and the outer surface of the outer panel of the right casing  149  forms the completely flat outer surface  157  of the outer side panel of the tray container. 
         [0047]    Four rectangular mounting openings  158 ,  159 ,  160  and  161  are invariably formed at the bottom of the bottom panel  125  which will engage with the upstanding right angled mounting tabs  152 ,  153 ,  154  and  155  when two tray containers of the second embodiment are to be stacked together as shown in  FIG. 12 . 
         [0048]    Two pull-out trapezoidal shaped mounting tabs  162  and  163  are formed in the bottom panel  125  which may be pulled downward to lie perpendicular to the bottom panel  125  as shown in  FIGS. 9 and 12 , so that these trapezoidal shaped mounting tabs in a tray container located at top may engage by inserting into mounting slots  164  and  165  formed at the top panels  148  and  149  respectively of the tray container located at the bottom when two tray containers are stacked together to provide additional securement between the two tray containers to withstand external accidental impact to the stack. 
         [0049]    A plurality of the tray container of the second embodiment may be stacked together as shown in  FIG. 13 . 
         [0050]    Two pull-out trapezoidal mounting tabs  166 ,  167  and  168 ,  169  may be alternatively provided at the side edge portions of the bottom panel of the tray container as shown in  FIG. 14  together with complementary mounting slots formed at the top panels of the tray container, so as to provide still additional securement between two tray containers stacked together to withstand accidental external impact to the stack. 
         [0051]    While there is described above the exemplary embodiments of the present invention, it is to be clearly understood that the description is made only by way of example and not as a limitation to the scope of this invention.