Knocked-down polygonal container with set-up contour-forming flaps
BACKGROUND OF THE INVENTION AND PRIOR ART 
     This invention relates deals with fiberboard containers, such as those made from corrugated board, which are of the larger sizes intended mainly for packing and shipping bulk material and which are usually carried on pallets. Many of these containers are of square or rectangular from and the vertical wall panels thereof tend to bulge transversely and in a vertical direction when they are stacked. This is due to the fact that the compressive strength of the box is derived mainly from the vertical fold corners thereof. Attempts have been made in the prior art to increase the compressive strength by changing the cross-sectional shape of the container from quadrangular to a polygonal shape having more than four corner fold lines or joints so as to increase its compressive strength and thereby resistance to bulging upon stacking. However, usually this causes difficulty in setting-up the tubular body of the container from the flat knocked-down condition in which it is supplied, as it is a struggle to get it to assume and retain the proper polygonal shape unitl it is fastened in that shape. In many cases, it is necessary to provide a separate end tray of proper polygonal form in which the tubular body is set and secured to obtain and retain its shape. 
     SUMMARY OF THE INVENTION 
     The present invention provides a container made substantially without waste of material from a blank of fiberboard, preferably corrugated board, so that when it is set up it will be of polygonal horizontal cross-section with vertical fold lines providing more than four angular joints or corners. It is preferably of elongated octagonal form and is of large size to hold bulk material though not necessarily so. It is provided with a bottom flap arrangement with hinged flaps connected to each of the side panels, with the two flaps hinged to the main or longer panels, being of such area and shape, that when their free edges are brought together, they will have the complete cross-sectional area and contour of the polygonal tubular body of the container to be set up. As the body is set up and the inner edges of the form flaps are brought together, the tubular body is expanded and formed around the remaining free edges of the form flaps to the exact complete polygonal shape and cross-section desired. The flaps may be secured together or attached to a pallet to retain the set-up size and shape. No exterior forming means is needed. Thereafter, the multiple vertical fold joints or corner angles will serve to more adequately resist bulging upon stacking. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The best mode contemplated in carrying out this invention is illustrated in the accompanying drawings in which: 
     FIG. 1 is a side elevational view of a container embodying this invention and indicating how another can be stacked on it. 
     FIG. 2 is a plan view of the container. 
     FIG. 3 is a plan view of the blank for the container. 
     FIG. 4 is an elevational view of the flat knocked-down container formed from the blank. 
     FIG. 5 is a schematic bottom view showing the start of the setting up of the container. 
     FIG. 6 is a similar view showing the next step where the form-flaps of the bottom are brought together to produce the complete polygonal cross-section or contour of the tubular container body. 
     FIG. 7 is a plan view of the bottom after all the bottom flaps are folded into place. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With specific reference to the drawings, in FIG. 1, there is illustrated a container 10 of elongated octagonal form made according to this invention. It is shown resting on a pallet 11, although this is not necessarily so. A cap 12 of the inverted tray type is shown slipped over its upper end but the specific structure of this cap is not important to this invention. The set-up body of the container is tubular and its top edge may be provided with the flap arrangement 13 but other flap arrangements may be provided if desired. This invention relates mainly to the bottom flap structure indicated generally at 15 in FIG. 2 and which is shown fastened to the pallet 11 by staples 14. In FIG. 1, it is indicated that two or more of the containers of this invention can be stacked since the container is designed and constructed to resist bulging. This is due mainly to the provision of the eight corners instead of the usual four on this type of bulk material container. However, to facilitate the setting up of the container, the bottom flap arrangement 15 is of special design and construction. 
     The container 10 is made from the blank 10a indicated in FIG. 3. For simplicity, this blank is shown as a single lamination, preferably of corrugated board, but in actual practice, may be of two or more laminations. It is cut, slit and scored to provide the wall-forming panels 21, 22, 23, 24, 25, 26, 27, and 28 hinged together along vertical score lines 29. When the container body is set up into tubular form, these panels will provide the eight vertical walls with corners at each hinge line 29. Hinged to the panel 28 at a vertical score line 29 is a construction or attaching flange 30 which is adapted to overlap the outer edge of panel 21 when the tubular body of the container is formed. If the flap arrangement 13 is to be provided, the panels 21, 22, 23, 24, 25, 26, 27 and 28, will have hinged thereto at the horizontal score lines 31, the respective flaps 21a, 22a, 23a, 24a, 25a, 26a, 27a and 28a which are separated by slots 33. As indicated before, the bottom flap arrangement 15 is special and will consist of the flaps 21b, 22b, 23b, 24b, 25b, 26b, 27b and 28b, hinged to the respective flaps 21, 22, 23, 24, 25, 26, 27 and 28 along the horizontal score lines 32. In addition, a flap 30b is hinged to the flange 30 along score line 32. 
     It will be noted that the blank 10a can be formed from a sheet of material with substantially no loss of material. To produce the tubular container body, the blank will be folded at two vertical hinge lines 29, the one being between the panels 22 and 23 and the other being between the panels 26 and 27, as indicated in FIG. 4, to provide the knocked-down flat which is the condition the container is in when received by the packer. The flange 30 will be glued or otherwise attached to the panel 21 and the flap 30b to the flap 21b so that the flap assembly 21c will be the same size and shape as flap 25b. The two flaps 23b and 27b are what may be termed the form flaps and with their outer edges brought together, in setting up the knocked-down tubular body, will provide an area and contour corresponding to that of the octagon tubular body which it is desired to set up. It will be noted that these flaps project downwardly in FIG. 4 along with the other bottom flaps. The largest flaps 23b and 27b will be on the elongated side walls to be formed by panels 23 and 27 and will project in opposite directions beyond each corner hinge joint 29 thereof, the next larger flaps 21b and 25b will be on the end walls to be formed by panels 21 and 25 and the small triangular flaps 22b, 24b, 26b and 28b are on the panels 22, 24, 26 and 28 which will be on the small angular connecting walls. 
     The size and shape of the form flaps 23b and 27b are critical. Each flap is of hexagonal shape and equal in area to onehalf the cross-sectional area of the tubular body of the container. At the hinge joint 32, each of these flaps is coextensive with the side panel 23 or 27 to which it is hinged. However, the outer free edge 35 of each form flap is longer, being of an extent equal to the length of the container between the end walls 21 and 25 and is parallel to the inner edge. These edges 32 and 35 preferably are spaced apart one-half the distance desired between side walls to be formed by panels 23 and 27. The opposite angular edges 36 and 37 are each at the same angle as the respective connecting walls 22 and 24 or 26 and 28 with which they are to cooperate and are of the same extent as the width of the walls. The remaining opposite straight end edges 38 and 39 are parallel with each other and at right angles to the edges 35 and 32 and further are of one-half the width of the end wall panel 21 or 25. The small flaps 22b, 24b, 26b and 28b, are triangular and are hinged to the respective connecting wall panels 22, 24, 26, and 28 at the hinge joints 32. The single end flap 25b and the opposed end flap assembly 21c will be hinged to the connecting wall panels 25 and 21, respectively, and will be coextensive therewith at the hinge joints. As previously indicated, the end flap assembly 21c is a combination of flaps 21b and 30b. 
     In setting up the tubular container body from the knocked-down condition of FIG. 4, the first step is indicated in FIG. 5, which eliminates the top flap arrangement 13 for clarity. In this Figure, the body is shown being expanded and the form flaps 23b and 27b are partially turned inwardly. As the inner edges 35 thereof are brought together, the tubular body will be expanded to its proper polygonal shape with the main elongated side walls 23 and 27 opposite, as shown in FIG. 6, and at the same time the end walls 21 and 25 and the connecting angular walls 22, 24, 26 and 28 will be formed around the remaining free edges 38, 39, 36 and 37 of the form flaps 21b and 27b. This will complete the expansion and formation of the tubular body into the complete elongated octagonal shape. Then, the smaller triangular flaps 22b, 24b, 26b and 28b are turned inwardly into overlapping relationship to the form flaps 23b and 27b and, finally, the end flaps 21c and 25b, are turned inwardly over the overlapping triangular and form flaps. Then, the formed container may be rested on a pallet 11 and be secured thereto by staples 14 through the overlapping bottom flaps. If a pallet is not used, the overlapping bottom flaps may be stapled or otherwise fastened together. All the various flaps, when fastened together, will tend to keep in place the vertical walls to which they are hinged and prevent outward movement thereof at their lower portions. 
     It will be apparent that this invention provides a fiberboard container of polygonal tubular form with more than four corners to obtain increased compressive strength. The container is made from a single sheet of material with practically no waste and is supplied in knocked-down form. Setting up is facilitated by the bottom flap arrangement which consists of at least two form flaps hinged to side wall panels of such size and shape that, when their inner edges are brought together, they bring the attached panels into position and provide a form for the complete contour and area of the desired polygonal tubular body.