Collapsible corrugated plastic box

Abstract

This invention provides a collapsible box made of corrugated plastic, which has improved hinge line/score line configurations between walls and panels and improved hand holds. A plastic box of this invention preferably has an automatically lockable bottom to facilitate erection of the box, and can be easily collapsed for return shipment and reuse.

What is claimed is:  
     
         1 . A collapsible box made of corrugated plastic comprising at least four vertical side walls and a bottom end flap integrally connected to each of said side walls through a hinge line, wherein the hinge line between adjacent side walls and their respective bottom end walls are vertically offset.  
     
     
         2 . A collapsible box as set forth in  claim 1  in which each of said hinge lines between each said side wall and its respective end flap comprises a crushed score line and a perforated score line substantially parallel to said crushed score line.  
     
     
         3 . A collapsible box as set forth in  claim 1  which has at least one hand hold cut into a said side wall of the box, said hand hold comprising a cut line through said corrugated plastic to define a hinged flap in the side wall with said cut line on both sides and the bottom of said flap and ending in a rounded corner at the top of each side of said flap.  
     
     
         4 . A collapsible box as set forth in  claim 1  that includes a top end flap connected to each said side wall through a hinge line.  
     
     
         5 . A collapsible box as set forth in  claim 4  which includes slots cut between adjacent top flaps and adjacent bottom flaps, and crushed vertical score lines between adjacent side walls with each of said vertical score lines terminating short of said slots.  
     
     
         6 . A collapsible box as set forth in  claim 5  in which said vertical score lines terminate approximately ½ inch short of each slot.  
     
     
         7 . A collapsible box as set forth in  claim 1  in which said hinge lines between said top flaps and said side walls terminate short of the edges of the side walls and top flaps.  
     
     
         8 . A collapsible box as set forth in  claim 7  in which said hinge lines between said top flaps and said side walls terminate approximately 1 inch short of the edges of the side walls and top flaps.  
     
     
         9 . A collapsible box as set forth in  claim 1  which is rectangular in horizontal section with four said vertical side walls including two length walls and two width walls, and said hinge line between said two width walls and their bottom end flaps are offset below the hinge lines between said length walls and their bottom end flaps.  
     
     
         10 . A collapsible box as set forth in  claim 9  in which said offset is approximately equal to one or two times the thickness of said corrugated plastic.  
     
     
         11 . A collapsible box as set forth in  claim 1  in which said bottom end flaps comprise an automatic lock bottom.  
     
     
         12 . A collapsible box as set forth in  claim 11  in which said side walls include two length walls and two width walls, and said automatic lock bottom comprises each of said bottom flaps on said width walls being hingedly connected to one of said bottom flaps on said length walls along hinge lines that bisect the corners between said bottom flaps.  
     
     
         13 . A collapsible box as set forth in  claim 12  in which said bottom flaps are adhesively connected.  
     
     
         14 . A collapsible box made of corrugated plastic comprising: 
 two vertical width walls;    two vertical length walls;    a bottom width flap attached to each said width wall through a hinge line;    a bottom end flap attached to each said length wall through a hinge line;    one of said bottom end flaps hingedly connected to one of said width flaps along a diagonal hinge line and the other said bottom end flap hingedly connected to the other said width flap along a diagonal hinge line to form an automatic lock bottom to said box; and    said hinge lines between each of said width walls and their respective width flaps and between each of said end walls and their respective end flaps comprising a crushed score line and a perforated score line which is substantially parallel to said crushed score line.    
     
     
         15 . A box as set forth in  claim 14  in which said score lines between said width walls and said width flaps being offset slightly below said score lines between said length walls and said flaps on said length walls.  
     
     
         16 . A collapsible box as set forth in  claim 14  which includes a hand hold in each of said vertical width walls and each hand hold comprises a cut line through said corrugated plastic defining a hinged flap depending from a hinge line.  
     
     
         17 . A collapsible box as set forth in  claim 16  in which said cut line terminates in a rounded corner on both ends of said hinge line from which said flap depends.  
     
     
         18 . A collapsible box as set forth in  claim 14  which includes vertical hinge lines between each width wall and each length wall and said vertical hinge lines terminate short of the top and bottom of said walls.  
     
     
         19 . A collapsible box as set forth in  claim 14  in which said hinge lines between said width walls and their respective width flaps and said length walls and their respective width flaps all terminate short of the sides of said walls on both ends of each said hinge line.  
     
     
         20 . A collapsible box as set forth in  claim 19  in which said hinge lines all terminate approximately one inch short of the sides of said walls on both ends of each said hinge line.  
     
     
         21 . A collapsible box made of corrugated plastic comprising at least four vertical side walls and a bottom end flap integrally connected to each of said side walls through a hinge formed by a score line in said corrugated plastic, said score lines terminating short of the edges of said end flaps to reduce possible risk of tearing the corrugated plastic.  
     
     
         22 . A collapsible box as set forth in  claim 21  that includes a top end flap integrally connected to each of said side walls through a hinge formed by a score line in said corrugated plastic.  
     
     
         23 . A collapsible box as set forth in  claim 21  in which said side walls are connected to each other through a hinge formed by a score line in the plastic and said score lines terminate short of the tops and bottoms of said side walls to reduce possible risk of tearing the corrugated plastic.  
     
     
         24 . A collapsible box as set forth in  claim 21  in which said side walls of the box comprises two length walls and two width walls having less horizontal extent than said length walls, and said hinge between the width walls and their bottom end flaps is offset downwardly from said hinge between said length walls and their bottom end flaps.  
     
     
         25 . A box as set forth in  claim 21  which includes hand holds in two opposing side walls with a cut line along three sides of each said hand hold, and said cut line terminates in a rounded corner at the top of each side of the hand hold.  
     
     
         26 . A box as set forth in  claim 21  in which said bottom end flaps form an automatically lockable bottom end closure for the box.  
     
     
         27 . A collapsible box made of corrugated plastic comprising at least four vertical side walls separated by vertical hinge lines therebetween formed by score lines in the corrugated plastic and a bottom end flap integrally connected to each of said side walls through a hinge therebetween, said score lines forming said vertical hinge lines stopping short of the top and bottom of said side walls to reduce possible risk of tearing the plastic along the score lines.  
     
     
         28 . A collapsible box as set forth in  claim 27  that includes an automatically lockable bottom end closure.  
     
     
         29 . A collapsible box as set forth in  claim 27  that includes hand holds in two opposing side walls, with each said hand hold being defined by a cut line along the bottom and both sides of said hand hold and said cut line terminates in a rounded corner of the top of the hand hold on both sides of the hand hold.  
     
     
         30 . A collapsible box as set forth in  claim 27  in which the hinge line between said side walls and said bottom end flaps comprises two parallel score lines.  
     
     
         31 . A collapsible box as set forth in  claim 30  in which one of said parallel score lines is a perforated score and the other is a crushed score.  
     
     
         32 . A collapsible box as set forth in  claim 31  in which said crushed score is below said perforated score.  
     
     
         33 . A collapsible box as set forth in  claim 32  in which said crushed score is in the interior face of the side wall and said perforated score is in the exterior face of the side wall.  
     
     
         34 . A collapsible box made of corrugated plastic comprising at least four vertical side walls and a bottom end flap integrally connected to each of said side walls through a hinge line, and a hand hold cut into at least one of said side walls, said hand hold comprising a cut line through said corrugated plastic to define a hinged flap in the side wall with said cut line on both sides and the bottom of the flap and ending in a rounded corner at the top of each side of said flap.  
     
     
         35 . A collapsible box as set forth in  claim 34  which has at least two of said hand holds, and said two hand holds are in opposite side walls of the box.  
     
     
         36 . A collapsible box as set forth in  claim 35  in which said hinge line for each hand hold comprises a score line.