Abstract:
The present invention is a method and means for making a carrying case from two open topped boxes from sandwich wall construction, where one box will be lid and the other a base. Living hinges connect a floor section to four sidewalls ensuring accurate vertical alignment of the sidewalls with each other and with the floor section.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to boxes with layered or sandwich wall construction, especially those which must withstand severe torsion forces.  
         [0002]     The layered walls in construction of boxes is useful in that lighter and less expensive materials may be used as a fill material between two rigid sheets. It is well known to use polymer foam material such as styrofoam or other rigid foams between two rigid polymer sheets to form a sheet of exceptional lightness, insurability and strength. However, the desired features of such a sandwich wall or sheet are not easily obtained.  
         [0003]     While an unassociated sandwich sheet is very strong, excessive flexing, shock or vibration causes the rigid sheets to delaminate from their bonded connection to the Styrofoam. This delamination essentially destroys a major part of the wall strength. Subsequent blows or strikes against a delaminated sheet causes the force of the blow or strike to be focused on a small area instead of being distributed over the entire sheet. The rigid polymer foam is then compressed or broken into fragments, causing delamination of the polymer sheet on the other side of the sandwich wall. When such sandwich walls are used in box construction, bonded connections between individual wall pieces becomes difficult to achieve while ensuring precise orientation of all the other pieces in the box. Failure to obtain such precise orientation results in a box that will fail.  
         [0004]     U.S. Pat. No. 4,744,445 describes components and methods for assembling storage cases. Storage cases are made for a wide variety of applications including transportation, shipping and storage and are required in a wide variety of shapes and sizes. The &#39;445 patent describes a kit for assembling a case having a base and a lid from a series of separate parts is provided, the kit allowing cases of any chosen dimensions to be made. The assembly kit was described as a series of panels of any chosen dimensions for forming the bottom, side and end walls of an open topped box-like enclosure base, and similar panels for forming a lid for closing the open top of the base, a series of angled corner strips for connecting adjacent edges of the panels together along the longitudinal and side edges of the base and lid to form the box-like enclosures, a hinge mechanism for hinging the lid to the base, and a latch mechanism for releasably closing the lid. The kit also included mateable or co-operable edge strips for securing around the open upper end of the base and lower edge of the lid, respectively, for mating engagement with one another when the lid is closed to restrict movement of the lid relative to the base. Also provided in the kit were corner pieces for securing at the lower four corners of the base and the upper four corners of the lid. Metable corner pieces were provided in the kit which are of similar configuration to the mateable edge strips for securing to the upper and lower corner edges, respectively, of the base and lid. The disclosure U.S. Pat. No. 4,744,445 is incorporated herein.  
         [0005]     Although useful for careful hobbyists, the kit of the &#39;445 patent was the subject of many product returns. A single mis-aligned connection among the several bonded (i.e., via glue, thermal welding or other such polymer bonding methods) connections that were needed to make the case would result in a useless collection of pieces. So many returns were experienced that actual construction of the cases according to the &#39;445 patent was performed by Melmat, Inc. in Huntington Beach, Calif., a company experienced in manufacturing and assembly of plastic devices. Although the cases described in the &#39;445 patent can with care be assembled by professionals, it would be desirable to reduce the manufacturing care requirements to reduce manufacturing time and cost.  
         [0006]     The case according to the &#39;445 patent is shown and described using wall material of a single layer. The thickness of the wall material is relatively thin. It has been found that the wall material of the case according to the &#39;445 patent is relatively weak compared with boxes formed with sandwich walls. However, the &#39;445 patent and the prior art fail to indicate how the case of the &#39;445 patent could be change to accommodate sandwich wall construction. There is a need for a case having the reduced number of manufacturing components as that of the &#39;445 patent while obtaining the benefits of sandwich wall construction.  
       SUMMARY OF THE INVENTION  
       [0007]     The invention comprises methods and means for ensuring sandwich wall alignment in a kit box or easily assembled box. The component panels or walls of the box are cut from a large assembly sheet formed of a core of rigid polymer foam, such as styrofoam, and sandwiched between two layers of rigid polymer sheets, preferably ABS (acrylonitrile-butadiene-styrene). The assembly sheets are formed in relatively large sheets, such as four by eight feet, and stored until an order for an invention box is received by a vendor for the invention box. The assembly sheets have an overall uniform thickness of about one centimeter or more. An inner polymer sheet is preferably about one half the thickness of an outer polymer sheet.  
         [0008]     In the invention method, two types of router cuts are made in the assembly sheet to form all the sandwich walls of the invention box or case. In this method, five sandwich walls of an open topped box are connected with living hinges to a floor section. After assembly as described below, two of such open topped boxes are connected by a hinge as described in the &#39;445 patent to form an assembled case.  
         [0009]     A first router cut defines a floor section. The floor section is rectangular and defined by four peripheral grooves in the outer polymer sheet. Extending inward from each peripheral groove is a 45 degree slope cut into the foam core and inner polymer sheet. The peripheral groove removes sufficient material from the outer polymer sheet to form a living hinge. Extending perpendicular to and outward from each peripheral groove is a sidewall section, four sidewall sections in all. Each sidewall section comprises two additional, second router cuts. These router cuts are similar to first router cuts except that the outer polymer sheet is cut through entirely. A distal edge of each sidewall section is cut at a 90 degree angle with respect to the surfaces of the assembly sheet.  
         [0010]     The floor section and sidewall sections are continuously connected through the outer polymer sheet to form the sandwich walls section. Each sidewall section extends from its peripheral groove outward from the floor section to define a reduceable sidewall height. While each sidewall must have the same sidewall height, that height can be changed by the manufacturer or kit assembler. A manufacturer can make and store several sandwich walls sections. Alternately, a kit assembler can receive an unmodified sandwich walls section. The manufacturer or kit assembler can easily make cuts off the free ends of each sidewall section, where those cuts are parallel with the peripheral groove. The ability to make these cuts gives the manufacturer or kit assembler a quick way to form an open ended box with precisely the height desired for a particular need.  
         [0011]     The peripheral grooves are hinges whereby the sidewalls can be rotated upward 90 degrees until they precisely and easily abut adjacent sidewall sections and the floor section at 45 degree sloped edges. An assembler impresses corner setting means to each of four top corners formed by raising the sidewalls.  
         [0012]     Corner setting means preferably comprise an edge piece in combination with a corner section of a closure edge. The edge piece is adapted to precisely align edges of adjacent outer polymer sheets of adjacent sidewalls. However, the edge piece must be urged properly into a space between those edges of adjacent outer polymer sheets of adjacent sidewalls. Impressing the corner section of a closure edge onto the edge piece effectively performs that task.  
         [0013]     When the bonding agent sets joining the abutting surfaces of the sloped edges, an assembler then adhesively applies edge pieces to all box edges excepting a top edge. To bottom corners, an assembler adhesively applies bottom corner pieces. To the top edges, the assembler bonds four corner sections of the closure edge respectively to the four top corners of the box. In a last step to form an open top box that will form one half of the invention case, the assembler adhesively connects to four free or open top edges a set of four top edge pieces of the closure edge.  
         [0014]     Two open top boxes formed according to the above method with mateable closure edges are connected by hinges and a releasable latch to form an invention case.  
         [0015]     In an alternate embodiment, only two sidewalls sections extend respectively from two grooves at opposite edges of the floor section. Two separate sidewalls are formed separate from the sandwich walls section to fit into the two vacant sidewalls areas. The benefit of obtaining precise orientation is somewhat reduced with this embodiment, although some of the objects of the invention are obtained thereby.  
         [0016]     Preferably, all the parts or components of the kit are of plastics material and are secured to one another by bonding. The panels, angled corner strips and edge strips may be provided in standard sizes and lengths for cutting to size by the purchaser, or may be provided in pre-cut dimensions for assembling of predetermined size cases by the purchaser. With this kit cases can be quickly, inexpensively and easily assembled in an unlimited range of sizes, simply by appropriate choice of the dimensions of the panels, corner and edge strips before bonding the various parts together. The lid and base are preferably of similar box-like format, and may be of the same or different depths as desired. According to another aspect of the invention a method of assembling a case of any chosen length, width and height from a kit of parts is provided, which comprises the steps of: 
        cutting a series of connected (via hinges) panels to predetermined dimensions to form the bottom, side and end walls of a box-like base and top, side and end walls of a box-like lid for the case;     bond corner angle strips along the adjacent edges of the side and end walls of the base and lid, respectively, to form a box-like rectangular enclosure, and along the adjacent edges of the bottom wall and adjacent lower edges of the side and end walls, and the edges of the upper wall and adjacent upper edges of the side and end walls of the lid, respectively to form right angle joints between the respective panels and provide two separate box-like enclosures;     bond closure strips having a first mateable formation along at least part of the open edge of one of the formed enclosures and bond closure strips having a second formation mateable with the first along at least part of the open edge of the other formed enclosure;     bond a two part hinge mechanism to the base and lid enclosure, respectively, to form a hinge connection between the lid and base (although hinges and hasps may be mechanically fastened by bolts or screws); and     bond a first part of a latch mechanism to the lid and a second part of a latch mechanism to the base, the two parts being releasably connectable together to releasably secure the lid to the base in its closed position.        
 
         [0022]     The kit assembly may also include a carrying handle which may be bonded or otherwise secured to the assembled case, feet members or pads for securing to the bottom of the case, and one or more cover stops for securing to the inside of the case to hold the lid or cover partially or completely open. The hinge mechanism may comprise one or more hinges each formed from two separable hinge parts which are preferably only separable in one particular orientation of the two hinge parts to prevent the lid from becoming accidentally separated from the base. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a perspective view of an assembly sheet.  
         [0024]      FIG. 2  is a side view of an assembly sheet after having a first router cut.  
         [0025]      FIG. 2A  is a side view of an assembly sheet after having a second router cut.  
         [0026]      FIG. 3  is a top view of an assembly sheet made into a sandwich walls section after having first and second router cuts made according to the invention method.  
         [0027]      FIGS. 4, 5  and  6  are respectively top, end and side view of an edge piece.  
         [0028]      FIGS. 7, 8 ,  9  and  10  are respectively front upper perspective, end, side and top views of a corner piece.  
         [0029]      FIG. 11  is an upper perspective view of a broken away part of two sidewalls and a floor piece joined with edge pieces and a bottom corner piece.  
         [0030]      FIG. 12  is section  127  of  FIG. 11 .  
         [0031]      FIG. 13  is section  128  of  FIG. 11 .  
         [0032]      FIG. 14  is section  129  of  FIG. 11 .  
         [0033]      FIGS. 15 and 16  are respectively top perspective and bottom views of the sandwich walls section of  FIG. 3  assembled with edge pieces and bottom corner pieces.  
         [0034]      FIG. 17  is a broken away view of part of two sidewalls and a floor piece joined with edge pieces and a bottom corner piece and urged into alignment with a top corner piece.  
         [0035]      FIG. 18  shows additional detail of the closure edges of  FIG. 17 .  
         [0036]      FIG. 19  is a top view showing closure edges on a top edge of the box of  FIG. 11 .  
         [0037]      FIG. 20  is a top view of a top edge piece and a top corner piece adapted to receive an O-ring.  
         [0038]      FIG. 23  show inner side and end views of the top edge piece of  FIG. 20 .  
         [0039]      FIGS. 22 and 24  show respectively end and underside views of the top corner piece of  FIG. 20 .  
         [0040]      FIG. 25  is a top view of a top edge piece and a top corner piece adapted to mateably engage respectively the top edge piece and top corner piece of  FIG. 20 .  
         [0041]      FIG. 26  is an end view of the top corner piece of  FIG. 25 .  
         [0042]      FIG. 27  show inner side and end views of the top edge piece of  FIG. 25 .  
         [0043]      FIG. 28  is a broken away end view of the top corner pieces of  FIGS. 22 and 26  and engaged sidewalls, with the top corner pieces mateably engaged as they would be when the invention case comprises two box sections connected by hinges and latched into a closed position.  
         [0044]      FIG. 29  is a top view of a top edge piece and top corner piece as in  FIG. 25  shown mounted on the sidewalls of  FIG. 17 .  
         [0045]      FIG. 30  is section  176  of  FIG. 29 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0046]     The invention is now discussed with reference to the figures.  
         [0047]      FIG. 1  shows assembly sheet  100  comprising inner polymer sheet  101  and outer polymer sheet  103  encasing core  102 . Inner polymer sheet  101  is preferably formed from a rigid polymer with a thickness of about from about 0.8 to 2.0 millimeters. Outer polymer sheet  103  is preferably formed from a rigid polymer with a thickness of about from about 1.5 to 4.0 millimeters, where sheet  101  is about one half the thickness of sheet  103 . Core  102  consists of a rigid polymer foam, such as styrofoam, having an overall thickness of about from one half centimeter to three centimeters. As  FIG. 2  shows first router cut outline  111  having made a first router cut in the assembly sheet so that V-cut  112  is made separating inner polymer sheet and core sections to form portions  109  and  110  and forming groove  113  in outer polymer sheet  103 .  FIG. 2A  shows second router cut outline  106  having made a second router cut in the assembly sheet so that V-cut  107  is made separating inner polymer sheet, core and outer polymer sheet sections to form portions  104  and  105  and forming 90 degree cut  108  in the outer polymer sheet. These first and second router cuts are critical to achieving the objects of the invention.  
         [0048]      FIG. 3  shows an assembly sheet after receiving desired first and second router cuts to form a flat sandwich walls section  100 A. First router cuts  114  define floor section  117  attached by living hinges  113  (as in  FIG. 2 ) to sidewalls  118  through  121  so that sidewalls  118  through  121  can rotate along paths  122 . Sidewalls  118  through  121  receive lateral second router cuts  115  to form surfaces that will abut when the sidewalls are rotated up along paths  122  so that the sidewalls are substantially perpendicular to floor section  117 . Distal edges  116  of the sidewalls are cut to form a 90 degree angle with the polymer sheets that sandwich the foam core.  
         [0049]     Each of the sidewalls of  FIG. 3  have a box height defined by the distance from the peripheral groove in cuts  114  to edges  116 . This box height is predetermined in one embodiment so that it is equal to or greater than the tallest box typically required for a floor section  117  size. For instance, if the inner polymer sheet of floor section  117  is a twelve inch square, customers might typically not want a box height greater than twenty four inches, although many customers have ordered boxes with heights from six inches to twenty inches in height. The box height of the sidewalls in this example would be twenty four inches at the initial manufacturing step. Many such sandwich walls sections  100 A may be profitably manufactured at a single substantially continuous operation instead of making them one at a time. If a box with a box height less than twenty four inches is ordered, i.e., say sixteen inches, cuts  125  can be quickly made and the box assembled with the desired height. With sandwich walls section  100 A manufactured with a maximum box height, a customer may purchase such a section  100 A as a part of a kit to assemble the invention case and easily reduce the box height after purchase to obtain a desired box height.  
         [0050]      FIGS. 4 through 6  and  12  show edge piece  123  used on all vertical edges of an assembled box.  FIG. 14  shows edge piece  123 A used on bottom edges of the assembled box. The interaction of edge piece  123  and  123 A with the assembled box edges is critical to the invention.  FIG. 12  shows that groove  131  is formed in the interior length of edge piece  123 , groove  131  being capped with longitudinal ridges  132  on either side of groove  131 .  FIG. 12  shows that ridges  132  and groove  131  cooperate to separate the square edges of the outer polymer sheets of sidewalls  118  and  119  with a tolerance permitted by compression of ridges  132  into groove  131 . Surprisingly, the equivalent function has been found to be duplicated in the combination of the folded peripheral groove  134  and edge  123 A of  FIG. 14 , where groove  134  permits the same slight edge to edge compression of the outer polymer sheets as groove  131  of edge piece  123  in  FIG. 12 . With sandwich wall construction in the invention box, precise alignment of the outer polymer sheets in the assembled box is critical to obtaining required box strength. As described below, use of the living hinges of the peripheral groove and use of corner alignment means are necessary steps for relatively untrained persons to obtain an effectively applied edge section  123  in the assembled box according to the invention.  
         [0051]      FIGS. 7 through 10  show the bottom corner piece  124  that is adapted to be bonded to the outer surfaces of edge pieces  123  and  123 A at bottom corners of the box shown in  FIG. 11 . Bonded connections are made at: 
        (a) interface  126  shown in  FIGS. 11, 12  and  13  between the adjacent surfaces of the second router cuts on sidewalls  118  and  119 ;     (b) interface  133  shown in  FIG. 14  between adjacent surfaces on floor section  117  and sidewall  118 ;     (c) the contact interface between edge  123  and sidewalls  118  and  119  as in  FIG. 12 ;     (d) the contact interface between corner piece and edge pieces  123  and  123 A as in  FIGS. 11 and 13 ; and     (e) the contact interface between edge  123 A and floor section  117  and sidewall  118  as in  FIG. 14 .          
         [0057]      FIG. 15  shows an assembled box without closure edges. Interfaces  135 ,  136  and  137  are bonded interfaces as for interface  126 .  FIG. 16  shows a bottom view of the assembled box of  FIG. 15 .  
         [0058]      FIGS. 17, 18 , and  19  show closure edges  138  and  139  and top corner piece  140  adapted to engage edges  116  of the sidewalls. Corner piece  140  is further adapted to impress the ridges  132  of edge  123  into the space between the adjacent edges of outer polymer sheets (as in  FIG. 12 ) at the step of gluing interfaces  126 ,  135 ,  136  and  137  together to precisely align the sidewalls of the assembled box.  FIG. 17  shows that corner piece  140  comprises two flanges  141  and  142  spaced apart from the outer polymer sheet so that wall section  144  of closure edge  138  may be moved into that space by moving closure edge  138  in direction  148  so its end  147  abuts corner piece  140  to form an interface similar to that of interface  149  for closure edge  139 .  
         [0059]      FIGS. 21 and 23  show a gasket closure edge  151  comprising an outer wall  153  joined to an inner wall  152  by top section defining gasket groove  155  and alignment grooves  156 . The walls  152  and  153  and the top section define a longitudinal cavity  154  adapted to engage edge  116 .  FIGS. 21, 22  and  23  show a gasket corner piece comprising an outer wall  158  joined to an inner wall  159  by top section defining gasket groove  162  and alignment grooves  163 . An inside surface of wall  159  is adapted to engage a top part of the inner polymer sheets of the sidewalls at their top corners after bringing them into bonded connection as described above. An inside surface at the corner portion of wall  158  is adapted to urge an outer surface of edge  123  inward so that its ridges  132  precisely space apart edges of the outer polymer sheets. At the same time, the corner piece compresses adjacent sidewalls together to form a secure, bonded interface. The top corner piece acts to properly horizontally align the outer polymer sheets while the living hinge connecting the sidewalls to the floor section have provided proper vertical alignment.  
         [0060]      FIGS. 25 and 27  show a gasket closure edge  164  comprising an outer wall  166  joined to an inner wall  165  by top section defining gasket ridge  168  and alignment ridges  169 . The walls  165  and  166  and the top section define a longitudinal cavity  167  adapted to engage edge  116 .  FIGS. 25 and 26  show a sealing corner piece comprising an outer wall  171  joined to an angled inner wall  172  by a top section defining gasket ridge  174  and alignment ridges  175 . An inside surface of wall  172  is adapted to engage a top part of the inner polymer sheets of the sidewalls at their top corners after bringing them into bonded connection as described above. An inside surface at the corner portion of wall  171  is adapted to urge an outer surface of edge  123  inward so that its ridges  132  precisely space apart edges of the outer polymer sheets. At the same time, the corner piece compresses adjacent sidewalls together to form a secure, bonded interface. The top corner piece acts to properly horizontally align the outer polymer sheets while the living hinge connecting the sidewalls to the floor section have provided proper vertical alignment.  
         [0061]      FIG. 28  shows corner pieces  157  and  170  engaged respectively to sidewalls  118   a / 119   a  and sidewalls  118   b / 119   b  and brought together as they would be mateably engaged in a case comprising two boxes constructed as described above and connected by hinges and a latch. Interfaces  177  and  178  show that properly constructed boxes of the invention precisely mate along mateable closure edges and corner pieces with ridges  175  and  169  continuously respectively engaging grooves  163  and  156 . It is most preferred that ridges  175  and  169  continuously respectively engaging grooves  163  and  156  permit a lateral tolerance of 0.2 to 1.0 millimeter so that the ridges  175  and  169  are slightly movable laterally when engaged in a closed position. Accumulation of acceptable tolerance errors in routing and assembly of the top and bottom halves of the invention box are surprisingly easily resolved by such tolerance for dust-tight and spray-tight closure of the halves of the invention box.  
         [0062]      FIGS. 29 and 30  show assembly details of closure edge  164  and corner piece  170  mounted on edges  116  of engaged sidewalls.  
         [0063]     The above design options will sometimes present the skilled designer with considerable and wide ranges from which to choose appropriate apparatus and method modifications for the above examples. However, the objects of the present invention will still be obtained by that skilled designer applying such design options in an appropriate manner.