Patent Publication Number: US-2010111664-A1

Title: Method of using a sling jig assembly for loading and transporting bagged and bundled products

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. patent application Ser. No. 11/424,496, which itself claims the benefit from U.S. Provisional Patent Application No. 60/692,385 filed Jun. 20, 2005 whose contents are incorporated herein for all purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to containment systems and more particularly to methods and apparatuses for facilitating the loading operation of a sling device for use with transporting bagged or bundled goods. 
     2. Description of the Prior Art 
     Granulated products such as seed, fertilizer, grains, and the like are typically contained in nylon, cotton, burlap or plastic bags. When transporting mass quantities of such bags, the individual bags are stacked on pallets and lifted from below by forklift from place to place. When such products are shipped for export on a vessel, however, it is more common to stack such bags  100  within a soft-sided sling as shown in  FIG. 1 . Such a sling would fully envelop bags  100 , thereby preventing them from sliding from the stack when moved. 
     The sling includes a soft-sided outer bag  10  having a bottom  11  and sidewalls  13 , conventionally formed from a strong fabric such as nylon. Surrounding the bag  10  are a web of support straps, such as support straps. The particular sling embodiment shown in  FIG. 1  includes two straps on each vertical sidewall  13  of the sling bag  10 , such as straps  12   a,    12   b  along a facing sidewall of the bag and straps  12   c  and  12   d  along left and right sidewalls respectively. Strap guides  14   a - 14   d  receive straps  12   a - 12   d,  respectively, and wrap around the periphery of and especially underneath the bag  10 . The straps  12   a  through  12   d  connect together over the top of bag  10  so that forklift forks  16   a,    16   b  can be received within the gap  18  formed beneath the straps. 
     The traditional method for loading bags  100  within the sling is by hand. The sling is laid flat on a floor and workers would lift each bag or bundle from an unload point and place them within the sling. Once the sling is filled with stacked bags  100  as shown in  FIG. 1 , a forklift or overhead crane would lift the loaded sling by straps  12   a - 12   d  thereby causing the straps to cinch the sling closed. The act of individually moving bags to within the sling interior is extremely time intensive. 
     Accordingly, it is desired to provide a new process for loading bagged or bundled products within a sling for transport. 
     SUMMARY OF THE INVENTION 
     The apparatus uses a robotic arm to pick and place individual bags of material as they present themselves at the pick-up position on an in-feed conveyor belt. The bags are placed on an inside, bottom surface of a sling bag whose sidewalls have been rolled down. The sling bag sits atop a sling jig assembly that includes a raised central platform on which the sling bottom sits, and a gutter surrounding the platform into which the sling sidewalls are rolled down into. The jig further has an underside support structure that is adapted to sit on a conveyor belt. 
     In use, the jig is fitted with a sling by placing the sling bottom on the raised jig platform and rolling the sling sidewalls down into the gutter. The jig is placed on a load conveyor and rolled into place in a load position adjacent the robotic arm. The robotic arm moves individual bags from the pickup position to the load position and places the bags in preprogrammed orientations on the sling bottom and jig platform. Once the bags have been stacked in rows on the platform, the sling sidewalls are rolled upward over the sides of the stack of bags and attached together at the top of the stack to form an enclosed bag. The loaded jig is then moved by the conveyor to an unload position where a forklift or rods of an overhead crane are passed through lifting straps on the sling. The sling is then lifted from the jig and moved to its stored position in a warehouse for future loading onto a ship (e.g. the hold of a cargo ship). The jig is then fitted with another sling and then moved via the load conveyor back to the load position where the load and unload steps are again performed. 
     The foregoing and other objects, features and advantages of the invention will become more readily apparent from the following detailed description of a preferred embodiment of the invention that proceeds with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevation view of a sling loaded with bagged product. 
         FIG. 2  is a perspective view of a sling jig assembly constructed according to a preferred embodiment of the invention. 
         FIG. 3  is a plan view of the sling jig assembly of  FIG. 2 . 
         FIG. 4  is a side elevation view of the sling jig assembly of  FIG. 2  shown along a long side of the jig. 
         FIG. 5  is a side elevation view of the sling jig assembly of  FIG. 2  shown along a short side of the jig. 
         FIG. 6  is a perspective view of a load/unload assembly environment in which the sling jig assembly of  FIG. 2  is used. 
         FIG. 7  is a sectioned view of the sling jig, taken along lines  7 - 7  of  FIG. 3  with a sling bag mounted therein and product unloaded thereon. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 2  shows a preferred embodiment of a sling jig assembly at  20  in perspective view.  FIGS. 3-5  show top, front, and side views respectively. 
     Jig  20  is constructed to include an outer rectangular skirt  22  in which the four peripheral edges of skirt  22  are bent upward to form the flanges  24   a - 24   d.  Flanges  24   a - 24   d  are coupled together to adjacent flanges using metal ties, for instance metal tie  26  coupling flange  24   b  to flange  24   c  in  FIG. 2  and coupling flange  24   a  and  24   b  in  FIG. 3 . The metal ties are affixed to the flanges via a set of bolts  27 . 
     A raised platform  28  is placed on top of skirt  22  and between flanges  24   a - 24   d.  Platform  28  includes sidewalls  30  defining a rectangular periphery of platform  28  and having a raised platform top surface  32  that projects above a bottom surface formed within skirt  22 . The sidewalls  30  of the raised platform  28  and the flanges  24   a - 24   d  of the skirt  22  form a trough or gutter  33  therebetween that runs about the periphery of raised platform  32 . 
     A preferred embodiment of the jig  20  includes an array of apertures  34  formed through top surface  32  to allow air to escape as the sling is placed on the jig. Metal support struts  35  (shown in dashed lines in  FIG. 3 ) are fixed beneath top surface  32  to increase the strength of the jig assembly. A support structure affixed to an underside of the jig comprises sets of support beams  38  and  36  running perpendicular to one another. Beams  38 , positioned on each side of beams  36  to form a box therewith, extend below a bottom surface of beams  36  and are adapted to contact and sit on a conveyor, such as load conveyor  52  shown in  FIG. 6 . At set of spaced apertures  39  are formed through beams  38  to act as forklift pockets for side access and lifting of jig  20  by forklift means  56 . 
     In operation, and as shown in  FIGS. 6 and 7 , a sling  10  is positioned within the jig  20  so that the sling bottom  11  and portions of the straps  12  sit atop the jig raised platform  28 . The sling sidewalls  13  are then rolled down into the gutter  33  surrounding the raised platform  28  so that the sling sidewalls  13  make a negative angle (that is, angling downward) from the sling bottom  11 . In this way, the sling bag is almost inside out. Bagged products  100  are then placed atop the sling bottom  11  with the sidewalls  13  rolled out of the way and not interfering with placement of the bagged product within the sling. Once loading is completed, the sling sidewalls  13  are rolled up over the sides of the stacked product and enclose the stack. The straps  12  of the sling are then coupled together to allow a forklift or overhead crane to move the loaded sling to another location. 
       FIG. 6  is a plan view of a load/unload assembly environment in which the sling jig assembly of  FIG. 2  is used. The environment includes an in-feed conveyor  40  for transporting bagged products  100  serially to an unload position  42 . A robotic arm  44 , having an end effector or load/unload head  46  attached to a base  48  through a series of pivoted arms, engages with a bagged product at the unload position  42  whereby the load/unload head  46  of the robotic arm clamps on, thereby engaging bagged product  100 . The engaged bag is then moved to a load position within the sling  10  mounted on the sling jig  20 . Logic controls within the robotic arm are programmed to move between unload and load positions, with the load position changing with each successive pickup and placement depending upon where the next bagged product is to be placed on the stack. 
     Once loading is complete, the sling bag  10  can be rolled up over the stack as described above to form a wrapped bundle  50 . The sling jig  20  and bundle  50  are then moved by load conveyor  52  for transport to an unload position  54 . From the unload position, the loaded sling bag  10  is lifted from the jig  20  and moved for further transport, as via engagement of the tines  16   a,    16   b  of forklift  56  shown in  FIG. 6  with the straps  12  passing over the bundle  50  to create a webbing, to a subsequent shipping position  60 . The unloaded jig  20  is then moved back into place at the load position, or a new jig put in its place to receive further bagged product from the in-feed conveyor  40  via robotic arm  44 . 
     Having described and illustrated the principles of the invention in a preferred embodiment thereof, it should be apparent that the invention can be modified in arrangement and detail without departing from such principles. We claim all modifications and variation coming within the spirit and scope of the following claims.