Abstract:
A bulk bag is provided with a seamless bottom or base. The base is constructed of a single sheet of material which is folded at the corners thereby providing a continuous and seamless member which prevents leakage of material contained within the bulk bag as well as contamination of product within the bulk bag from the environment. An upper assembly of the bulk bag may either conform to the shape of the base, or may be of another shape as desired.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a flexible bag for holding bulk products, and more particularly, to a bulk bag having a seamless base which prevents leakage, avoids product contamination, and adds strength to the bulk bag.  
         BACKGROUND OF THE INVENTION  
         [0002]    Bulk materials are often transported in containers such as large flexible bags. Such material may include cement, plastic, grains, and the like.  
           [0003]    One example of a flexible bulk bag is that disclosed in U.S. Pat. No. 5,785,175. This particular bulk bag is especially adapted for lifting by the forks or tines of a fork lift. The bulk bag has a base, a plurality of sidewalls, and various forms of reinforcing members which add strength to the bulk bag.  
           [0004]    Many flexible bulk bags are manufactured from woven plastic fabric or other plastics of a flexible and sturdy nature. One particular problem with these types of flexible bags is that when they become wet, the contents of the bag can become contaminated through the seams or stitches which hold the various parts of the bag together. Thus, although the woven or plastic fabric itself may be impermeable, problems arise when the woven plastic fabric is joined along seams or stitches. Particularly when seams or stitches are formed on the bottom surface of the bulk bag, contamination can occur because the bulk bag will make contact with the ground. Seams or stitches along the bottom surface of the bag may reduce the overall strength of the bag. Over time, the seams can deteriorate due to moisture or other environmental conditions. Even if adhesive or heat sealing is used to join sections of fabric along a bottom surface, these methods of attachment can also deteriorate over time due to material stresses experienced by the bottom surface.  
         SUMMARY OF THE INVENTION  
         [0005]    The above disadvantages of the prior art are overcome by the construction of the bulk bag of the present invention. The present invention has a seamless base which prevents contamination of product contained within the bulk bag if the bulk bag becomes soaked or comes into contact with the ground or other surfaces. The present invention also provides an overlapping connection between the side panels and upstanding side edges oft he seamless base. The overlapping connection adds structural integrity and strength to the bulk bag. The base has a folded construction at the corners thereby eliminating the need to connect separate pieces of the base.  
           [0006]    Other advantages will become apparent from a review of the drawings taken along with the detailed description. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a perspective view of a single piece of material used to make the base of the flexible bag of the present invention;  
         [0008]    [0008]FIG. 2 is a perspective view showing the base and the fold lines incorporated on the base;  
         [0009]    [0009]FIG. 3 is another perspective view of the base shown as being partially folded during assembly;  
         [0010]    [0010]FIG. 4 is a perspective view showing the base fully folded;  
         [0011]    [0011]FIG. 5 is an exploded perspective view of the base prior to being attached to the sidewalls of the flexible bag;  
         [0012]    [0012]FIG. 6 is a perspective view showing the base attached to the sidewalls;  
         [0013]    [0013]FIG. 7 is another perspective view like FIG. 1 of the base prior to being folded;  
         [0014]    [0014]FIG. 8 is a perspective view similar to FIG. 2 showing the fold lines;  
         [0015]    [0015]FIG. 9 shows an alternative configuration of the base, the base being shown as partially folded;  
         [0016]    [0016]FIG. 10 shows the base being fully folded in accordance with the alternate configuration;  
         [0017]    [0017]FIG. 11 is an exploded perspective view of a second embodiment of the present invention wherein a continuous sidewall is provided of a cylindrical shape; and  
         [0018]    [0018]FIG. 12 is a perspective view of the second embodiment showing the cylindrical sidewall attached to the folded base of alternate configuration.  
     
    
     DETAILED DESCRIPTION  
       [0019]    [0019]FIG. 1 illustrates a single piece of material M which is used for the base of the present invention. In FIG. 2, the base  1  is shown with various fold lines which are used to fold the base for assembly. The base is defined by side edges  2 ,  3 ,  4  and  5 . Corners of the base are defined at  6 ,  7 ,  8  and  9 . The fold lines each intersect at intersection points  10 ,  11 ,  12  and  13 . Each corner includes two fold lines which are positioned at a right angle to one another, and a third diagonal fold line extends from the intersection point to the respective corner. Additional fold lines traverse the base which form the intersection of the side edges and the bottom surface of the base. As shown in FIG. 3, in a first configuration of the base, the base is folded along the various fold lines. The fold lines at each of the corners of the base define folded sections  14 . 1  and  14 . 2 ,  15 . 1  and  15 . 2 ,  16 , 1  and  16 . 2 , and  17 . 2  and  17 . 2 . In this first configuration, the folded sections are folded inward towards the center of the base  1 . As shown in FIG. 4, the folded sections are fully folded and then may be secured to the inner side or surface of the respective edges  2 - 5 . Areas of connection may be designated by the folded sections located at each corner of the base, shown in FIG. 4 as connections A, B, C and D.  
         [0020]    Referring to FIG. 5, an upper assembly of the bulk bag is shown prior to connection with the base  1 . The upper assembly of the bulk bag includes four side panels  22 ,  23 ,  24  and  25 . The side panels are joined to one another to form a square or rectangular shaped enclosure. A top panel  26  interconnects the upper edges of the side panels. A spout  27  attaches to the top panel  26 , and an opening is formed through the top panel  26  allowing the spout  27  to communicate with the interior of the enclosure. A plurality of loops may be attached to the side panels in a desired configuration allowing material handling equipment, such as a forklift, to engage the bulk bag for transport. As shown in FIG. 5, four loops are attached to the corners of the bulk bag. The loops are designated at  18 ,  19 ,  20  and  21 .  
         [0021]    [0021]FIG. 6 shows the bulk bag fully assembled. A stitch line  28  designates the points at which the upper assembly of the bulk bag attaches to the base. As can be seen, the lower edges of the side panels overlap the upstanding side edges of the base. Although a stitch line is shown in FIG. 6, it shall be understood that other means may be used to attach the base to the upper assembly of the bulk bag such as heat sealing, adhesive, or other well known means.  
         [0022]    Referring to FIG. 7, the piece of material M is now shown prior to being folded in a second configuration of the base.  
         [0023]    [0023]FIG. 8 is identical to FIG. 2 illustrating the various fold lines on the piece of material forming a base  48 . As with the first configuration, the second configuration includes a base having side edges  32 ,  33 ,  34  and  35 ; intersection points at  36 ,  37 ,  38  and  39  and designated corners at  40 ,  41 ,  42  and  43 .  
         [0024]    As shown in FIG. 9, the base is shown as partially assembled. In this second configuration, the folded sections are folded outward away from the center of the base  48 . The folded sections are designated at  44 . 1  and  44 . 2 ,  45 . 1  and  45 . 2 ,  46 . 1  and  46 . 2 , and  47 . 1  and  47 . 2 .  
         [0025]    [0025]FIG. 10 shows the base of the second configuration fully assembled. The folded sections are secured to the outer or exterior edges of the respective side edges. The areas of connection are designated at E, F, G and H. Thus, the second configuration differs from the first configuration only in the manner in which the folded sections are folded and attached to the side edges of the base.  
         [0026]    Referring to FIG. 11, the second embodiment of the invention includes an upper assembly having a cylindrical configuration, as opposed to a square or rectangular configuration. Cylindrical body  54  forms a continuous side panel and defines an enclosure. Top panel  53  attaches to the body  54  along the upper edge thereof. A spout  52  attaches to the top panel  53 . An opening is formed in the top panel  53  allowing the spout  52  to communicate with the interior of the enclosure.  
         [0027]    [0027]FIG. 12 shows the second embodiment fully assembled wherein stitch line  56  indicates the connection points between the upper assembly of the bulk bag and the base  48 . As with the first embodiment, in lieu of stitching, other well known means may be used to attach the upper assembly to the base to include heat sealing, adhesive and the like. Because of the round configuration of the cylindrical body  54 , there will be some degree of bunching or folding of material along the lower portion of the cylindrical body  54 . The lower edge of the cylindrical body  54  also overlaps the upstanding side edges of the base. The circumference of the cylindrical body  54  can be sized to match the combined lengths of the side edges of the base thereby enabling a smooth and continuous connection between the upper assembly and base.  
         [0028]    This invention has been described in reference to particular embodiments herein; however, it shall be understood that various modifications can be made which are still covered by the claims appended hereto.