Abstract:
The disclosed bulk bag storage rack facilitates both storage and unloading of a bulk bag and thereby eliminates the standard handling techniques heretofore required in transferring a bulk bag from a conventional rack to the bag unloader. The storage rack includes a bag suspension frame to which the bulk bag is attached. A base is shiftably intercoupled with the frame so as to permit vertical shifting between vertically expanded and contracted conditions. During storage, the rack is vertically contracted and the bag attached to the frame rests on the base, whereby the frame provides essentially no support to the bag. When it is desired to unload the bag, the frame is maintained at a desired height and the base is allowed to shift downwardly relative the frame. This eliminates the support provided by the base and the bag is consequently suspended from the frame. An unloading station includes a stand to support the frame at the desired height and a stop for limiting downward movement of the base.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to bulk bag support rack systems for facilitating storage of large bulk bags. More particularly, the present invention concerns a support rack that is designed to support a bulk bag during both storage and unloading. The present invention also particularly concerns a bulk bag storage and unloading system that includes a bag unloading station that cooperates with the inventive support rack to facilitate unloading of the bag supported by the rack. 
     2. Discussion of Prior Art 
     Bulk material (e.g., dog food, grain, etc.) will often be contained within large bags so as to facilitate transport, distribution and overall handling of the material. A standard bulk material bag typically includes a top material inlet and a bottom material outlet, such that material is loaded into the bag through the top inlet and unloaded through the bottom outlet. Furthermore, a bulk bag will often have an internal dimension of sixty-four cubic feet and be capable of holding as much as one ton of bulk material therein. 
     Those ordinarily skilled in the art will appreciate that bulk bags are unwieldy and that contact or direct handling of the bag is likely to risk bag punctures or complete bag failure. In this respect, a filled bag will typically be stored on a support rack that is designed to maintain the bag in an upright orientation. The support rack also permits the bag to be moved without the bag having to be contacted or directly handled. For example, the support rack may include a standard pallet-type base that can supported by the forks of a standard forklift. The filled bag supported on such a rack can consequently be moved without requiring any contact or direct handling. Conventional support racks are also typically configured to be stacked on top of one another so that the filled bags stored thereon are in effect stackable. 
     Even with such bag support rack systems, there is still the need to remove the bag from the support rack when it is desired to unload the bag. In other words, conventional support racks only facilitate storage of bulk bags and provide no support during or assistance with unloading of the bag. In most cases, the bag is lifted off the rack (e.g., by attaching the bag to a mobile lift such as an overhead chain hoist), moved by the lift to an unloading location (e.g., above the hopper of a screw conveyor), and then maintained in a suspended condition by the lift during unloading. Not only does suspension of the bag provide access to the bottom outlet, clogging is prevented and complete emptying of the bag is ensured. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     Responsive to these and other problems, an important object of the present invention is to provide a bulk bag storage and unloading system that eliminates user contact and handling of the bag. In this respect, it is an important object of the present invention to provide a bag support rack that is capable of supporting the bag during both storage and unloading of the bag. It is also an important object of the present invention to provide a bag support rack that facilitates unloading of the bag. In addition, an important object of the present invention is to provide a bag unloading station that cooperates with the bag support rack to facilitate unloading of the bag. Yet another important object of the present invention is to provide a bag storage and unloading system that has a durable, inexpensive and simple construction. 
     In accordance with these and other objects evident from the following description of the preferred embodiment, the present invention concerns a bag support rack including a bag suspension frame attachable to the bag in such a manner that the attached bag can be suspended from the frame. The rack also includes a base having a support surface configured to support the attached bag thereon. The frame and base are shiftably intercoupled so as to permit relative vertical shifting. The rack may consequently be vertically expanded from a storage condition in which the attached bag is at least primarily supported on the support surface to an unloading condition in which the attached bag is suspended from the frame. 
     The present invention also concerns a bag unloading station including a stand that is configured to support the frame and the attached bag. The stand includes a stop configured to engage the base, when the frame is supported on the stand and the rack is in the vertically expanded unloading condition, so as to prevent further downward shifting of the base relative to the frame. In this respect, if the frame and base are permitted to shift freely relative to one another between the storage and unloading conditions of the rack, the frame may be placed on the stand and the base will automatically drop relative to the frame to the unloading condition of the rack. The bag will then be suspended from the frame and ready for unloading. 
     Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     A preferred embodiment of the invention is described in detail below with reference to the attached drawing figures, wherein: 
     FIG. 1 is a perspective view of a bulk bag storage and unloading system constructed in accordance with the principles of the present invention; 
     FIG. 2 is an exploded perspective view of the bulk bag support rack forming part of system shown in FIG. 1; 
     FIG. 3 is a perspective view of the bag unloading station forming part of the system shown in FIG. 1; 
     FIG. 4 is a side elevational view of the bulk bag support rack and a bag being supported primarily by the base, with parts being broken away to illustrate the manner in which the bag suspension frame is attached to the bag; 
     FIG. 5 is a vertical cross-sectional view of the bulk bag storage and unloading system, particurlarly illustrating a bag suspended within the rack during unloading of the bag contents; 
     FIG. 6 is an enlarged, fragmentary cross-sectional view of bulk bag storage and unloading system, particularly illustrating the means by which the bag suspension frame is supported by the stand of the unloading station; 
     FIG. 7 is a front elevational view of a pair of stacked bulk bag support racks; and 
     FIG. 8 is an enlarged, fragmentary front elevational view of the interlocking structure provided on the racks to ensure proper and secure stacking of the racks. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning initially to FIG. 1, the bag storage and unloading system  10  selected for illustration generally includes a bag support rack  12  and a bag unloading station  14 . As will subsequently be described, the support rack  12  is configured to support a large bulk material bag  16  during storage and unloading of the bag  16  (e.g., see FIGS.  4  and  5 ). Furthermore, the support rack  12  is supported within the station  14  during unloading of the bulk bag  16 . 
     It is initially noted that the bulk bag  16  has a generally standard construction. Particularly, the preferred bulk bag  16  is formed of polypropylene and comprises a cylindrical outer wall  18  presenting open, top and bottom ends  20  and  22  (see FIGS.  4  and  5 ). In the usual manner, the bag  16  is preferably provided with a plastic liner (not shown). As shown in the drawing figures, the ends  20  and  22  are normally cinched to a closed condition by suitable means but are openable to permit loading and unloading of the bag  16 . Typically, the top end  20  serves as a material inlet used to fill the bag  16 , while the bottom end  22  serves as a material outlet through which material is discharged from the bag. The bag  16  is provided with four loops  24  spaced equally about the circumference of the outer wall  18  adjacent the top end  20 . The loops  24  are fixedly attached to the outer wall  18  and are typically formed of the same material as the outer wall  18 . As will subsequently be described, the loops  24  facilitate suspension of the bag  16  so that material may be discharged through the bottom end  22 . Those ordinarily skilled in the art will appreciate that the bulk bag  16  is capable of containing a large amount of material (e.g., in excess of one ton); however, the principles of the present invention are equally applicable to various other bulk material bag shapes and designs. Furthermore, the illustrated bulk bag  16  is available and often sold under the designation “SUPER-SACK”. 
     As particularly shown in FIG. 2, the support rack  12  comprises a lower base  26  and a upper bag suspension frame  28  that are intercoupled in such a manner that relative vertical shifting between the base  26  and frame  28  is permitted. As will be described further below, the support rack  12  is vertically expandable from a storage condition, in which the bag  16  is primarily supported by the base  26  (e.g., see FIG.  4 ), to an unloading condition, in which the bag  16  is suspended from the frame  28  and the base  26  provides essentially no support to the bag  16  (e.g., see FIG.  5 ). Furthermore, the unloading station  14  is designed to facilitate operation of the rack  12  as it expands from the storage condition to the unloading condition and during unloading of the bag  16 . 
     The base  26  includes a platform  30  that presents a flat, horizontal support surface on which the bag  16  may be placed and thereby supported. The illustrated platform  30  comprises a lattice of steel elements, although other suitable platform configurations (e.g., a steel plate, a lattice formed of wood or high-strength plastic, etc.) are within the ambit of the present invention. In particular, the illustrated platform  30  includes a rear cross-rail  32  extending perpendicularly between the ends of a pair of parallel, equal-length side rails  34  and  36 . A front cross-rail  38  is attached to the forward ends of the side rails  34  and  36  and is of sufficient length to project slightly outwardly beyond the side rails  34  and  36 . A pair of intermediate cross-rails  40  and  42  are secured between the side rails  34  and  36  in such a manner that the cross-rail  40  is spaced the same distance from the front cross-rail  38  as the cross-rail  42  is spaced from the rear cross-rail  32 . It is noted that the rails  32 , 34 , 36 , 38 , 40 , 42  are preferably formed of the same square-shaped tubular steel material. A pair of sectioned channel members  4 . 4  and  46  extend between the front and rear cross-rails  38 , 32 , with the intermediate cross-rails  40 , 42  dividing each channel member  44  and  46  into three sections. The preferred channel members  44  and  46  are formed of inverted U-shaped pieces of steel material. The top surfaces of the rails  32 , 34 , 36 , 38 , 40 , 42  and channel members  44 , 46  are at least substantially coplanar so as to cooperatively present the flat, horizontal bag support surface. The illustrated platform  30  is assembled by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     The base  26  further includes four vertically oriented posts  48 , 50 , 52 , 54  which are preferably formed of the same material as the rails  32 , 34 , 36 , 38 , 40 , 42 . The front posts  48  and  50  are attached to opposite ends of the front cross-rail  38  while the rear posts  52  and  54  are attached to the rear side of the rear cross-rail  32  at points spaced inwardly from the ends thereof. Thus, the posts  48 , 50 , 52 , 54  are disposed in a trapezoidal arrangement (when viewed from the top). The illustrated posts  48 , 50 , 52 , 54  are of equal length and are interconnected with the platform  30  so as to equally project upwardly and downwardly therefrom. The posts  48 , 50 , 52 , 54  and platform  30  are interconnected by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     The base further includes a pair of fore-and-aft feet  56  and  58  that are specifically designed to facilitate stacking of the rack  12  with other similarly configured racks. Turning first to the right foot  58 , a pair of notched plates  60  and  62  depend from the platform  30  so that their triangular-shaped notches are aligned along a fore-and-aft axis. An L-shaped bar  64  is secured within the notches of the plates  60  and  62 , such that the right foot  58  presents a downwardly open, triangular-shaped fore-and-aft recess  66 . The left foot  56  has a construction essentially identical to the right foot  58 , and it shall therefore be sufficient to explain that the left foot  56  includes a pair of notched plates  68 , 70  and an L-shaped bar  72  that cooperatively define a downwardly open recess  74 . The feet  56 , 58  and platform  30  are interconnected by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     The bag suspension frame  28  includes four vertically oriented, tubular sleeves  76 , 78 , 80 , 82  each of which is configured to telescopically receive a respective one of the posts  48 , 50 , 52 , 54 . The sleeves  76 , 78 , 80 , 82  are fixed relative to one another so that they synchronously slide along the posts  48 , 50 , 52 , 54 . In the preferred embodiment, the top ends of the rear sleeves  80  and  82  are fixed to the underside of a rear cross-rail  84 . The frame  28  further includes two uppermost pairs of fore-and-aft bars  86 , 88  and  90 , 92 , with each pair of bars being attached to the rear cross-rail  84  by a respective bracket  94  and  96 . The forward ends of the bars  86 , 88  and  90 , 92  are similarly attached to the tops of the sleeves  76  and  78  by brackets  98  and  100 , respectively. The bars  86 , 88 , 90 , 92  each comprise a square-shaped steel tube arranged so that its corners are disposed along the vertical and horizontal axes. In other words, the flat sides of each of the bars  86 , 88 , 90 , 92  are not horizontal and vertical, but rather are disposed at a 45° angle relative to the horizontal and vertical axes. It will be noted that the front sleeves  76  and  78  are slightly longer than the rear sleeves  80  and  82 , although the brackets  94 , 96 , 98 , 100  are arranged so that the bars  86 , 88 , 90 , 92  are generally level and do not slope downwardly toward the rear cross-rail  84 . The foregoing components of the frame  28  are interconnected by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     At each corner of the frame  28  is a chain assembly  102 , 104 , 106 , 108  that serves to attach the frame  28  to the bag  16 . As perhaps best shown in FIGS. 4 and 6, the right rear chain assembly  108  includes a hook element  110  projecting forwardly from the bracket  96 . The chain assembly  108  further includes a chain  112  having one end fixed to the hook element  110  and an opposite end that can be releasably secured to the element  110 . The remaining chain assemblies  102 , 104 , 106  are similarly constructed and will therefore not be described in detail. 
     Each of the inner fore-and-aft bars  88  and  92  of the frame  28  presents an upwardly projecting, triangular shaped flange (i.e., the uppermost corner of each of the bars) that is dimensioned to fit matingly within the downwardly open recess  74  and  66  of the respective foot  56  and  58 . That is to say, each of the innerbars  88  and  92  and the respective one of the recesses  74  and  66  are disposed along a common vertical plane (e.g., see FIG.  7 ). Because the system  10  will typically include a plurality of similarly configured racks, the feet  56  and  58  and bars  88  and  92  facilitate stacking of the racks. Such a stacked relationship is depicted in FIGS. 7 and 8, with the racks  12  and components thereof being referenced by the same numerals. It is particularly noted that the inner bars  88  and  92  of the lower rack are tightly received within the feet  56  and  58  of the upper rack. The upper rack is in fact supported on the bars  88  and  92  of the lower rack. Furthermore, the illustrated arrangement serves as a guide to facilitate proper stacking of the racks, with the user being permitted to place the upper rack on the lower rack and then make any adjustments in the fore-and-aft direction simply by sliding the feet  56  and  58  along the bars  88  and  92 . In addition, the illustrated arrangement limits relative side-to-side shifting of the upper and lower racks. 
     Again, the base  26  and frame  28  are slidably interconnected so that the rack  12  can be vertically expanded and contracted. It is noted that the lower ends of the sleeves  76 , 78 , 80 , 82  abuttingly engage the platform  30  and thereby limit vertical contraction of the rack  12 . As will subsequently be described, the frame  28  is designed so that bag  16  can be attached to but is not necessarily suspended from the frame  28  when the rack  12  is in the contracted condition (e.g., see FIG.  4 ). Downward movement of the base  26  relative to the frame  28  is not normally limited such that the base  26  and frame  28  can be disconnected. Accordingly, in a bulk bag storage and unloading system having a plurality of similarly configured racks, the bases and frames of the racks are interchangeable. In any case, the posts  48 , 50 , 52 , 54  and sleeves  76 , 78 , 80 , 82  are of sufficient length to permit vertical expansion of the rack  12  to a condition that causes the bag  16  to be suspended from the frame whereby the base  26  provides essentially no support to the bag  16  (e.g., see FIG.  5 ). 
     The bag  16  is preferably loaded onto the rack  12  when the latter is in the contracted condition. It is particularly noted that the bag  16  is conveniently loaded onto the rack  12  through the open front area defined above the platform  30 . The relatively long front cross-rail  38  causes the front to be relatively wide and ensures that sufficient clearance is provided between the bag  16  and rack framework. Furthermore, the rear posts and sleeves  52 , 54  and  80 , 82  are spaced inwardly from the sides of the rack  12  (e.g., see FIG. 7) to limit rearward movement of the bag  16  and thereby prevent the bag  16  from falling off the rear of the rack  12 . The bag is preferably arranged so that each of the loops  24  is adjacent one of the corners of the rack  12 , and the chain  112  of each chain assembly  102 , 104 , 106 , 108  is passed through the adjacent loop  24  and secured to the respective hook element  110 . The chains  112  are preferably drawn taut so as to assist in maintaining the bag  16  in an upright orientation but are not tightened to such a degree that the bag  16  is lifted off the platform  30 , as shown in FIG.  4 . Thus, when the rack  12  is in the contracted condition, the bag  16  rests on the platform  30  and is generally supported thereby. It is in this condition that the bag  16  is normally stored, and the rack  12  may be stacked with other bag-containing racks as shown in FIG.  7 . Furthermore, vertical expansion of the rack  12  from the contracted, storage condition will quickly remove the weight of the bag  16  from the platform  30  and cause the bag  16  to be suspended from the frame  28 . As indicated above, suspension of the bag  16  during unloading of its contents is desired. It is noted that the cinched bottom end  22  of the bag  16  is preferably located between the intermediate cross-rails  40 , 42  and channel members  44 , 46 , such that the bottom end  22  may be opened and material may pass through the platform  30  (see FIG.  5 ). The open area defined between the intermediate cross-rails  40 , 42  and channel members  44 , 46  consequently defines a material passageway extending through the platform  30 . The intermediate cross-rails  40 , 42  and channel members  44 , 46  also serve to prevent flailing movement of the bottom end  22  of the bag  16  which might otherwise occur during material discharge. Thus, the present invention not only permits the bag  16  to remain in the rack  12  during both storage and unloading, but also facilitates unloading of the bag  16 . If desired, vertical contraction and expansion of the rack may be powered (e.g., by a hydraulic piston and cylinder assembly, a solenoid, etc.), although this is not required as will be described hereinbelow. 
     The present invention also concerns the bag unloading station  14  that is used with the support rack  12  to unload the contents of the bag  16 . Particularly, the preferred bag unloading station  14  receives the rack  12  and serves to control vertical expansion of the rack  12 . The station  14  may also be provided with structure for receiving, managing and/or conveying the material discharged from the bag  16 . 
     As shown in FIG. 3, the illustrated bag unloading station  14  includes a stand  114  comprising four equal-length legs  116 , 118 , 120 , 122  that are each preferably formed of a square-shaped steel tube. A fore-and-aft beam  124  is fixed between the upper ends of the left legs  116  and  120 , and the right legs  118  and  122  are similarly interconnected by a fore-and-aft beam  126 . A vertical plate  128  attached to the rear faces of the legs  120  and  122  extends across the rear of the stand  114  and projects slightly above the legs  120  and  122 . The stand  114  further includes a pair of frame-supporting members  130  and  132 , each depending from a respective one of the fore-and-aft beams  124  and  126 . As perhaps best shown in FIG. 6, each of the frame-supporting members  130  or  132  presents a V-shaped shelf portion  130   a  or  132   a  that has a transverse configuration corresponding to the outer bars  86  and  90  of the frame  28 . In fact, the outer bars  86  and  90  and members  130  and  132  are configured in such a manner that the bars  86  and  90  nest matingly on the members  130  and  132  (see FIGS.  1  and  6 ). 
     The stand  114  further includes a pair of lower fore-and-aft beams  134  and  136  extending between and serving to interconnect the legs  116 , 120  and  118 , 122 , respectively. Disposed along the same horizontal plane as the fore-and-aft beams  134 , 136  are front and rear cross-beams  138  and  140  extending between and interconnecting the front legs  116 , 118  and rear legs  120 , 122 , respectively. The beams  134 , 136 , 138 , 140  are configured to engage the underside of the platform  30 , as shown in FIGS. 1 and 5, and thereby limit downward movement of the base  26  relative to the frame  28  when the rack is received within the station  14 . With the illustrated embodiment, when the frame  28  is supported by the stand  114  as a result of the bars  86  and  90  resting in the respective members  130  and  132 , the base  26  will drop freely until it engages the beams  134 , 136 , 138 , 140 . The stand  114  is assembled by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     Fixed to the underside of the front and rear cross-beams  138  and  140  is a hopper  142  that is positioned to receive material discharged from the bottom end  22  of the bag  16 , when the rack  12  and bag  16  are positioned within the station  14  (see FIG.  5 ). The hopper  142  serves to converge the discharged material as it flows downwardly. Those ordinarily skilled in the art will appreciate that the hopper  142  may be connected to any suitable device (e.g., a conduit, a material conveyor, etc.). In this respect, the illustrated station  14  may be placed over or form part of a conveying means such as a screw conveyor, belt conveyor, etc. The stand  114  and hopper  142  are interconnected by suitable means (e.g., mechanical fasteners, standard welding techniques, etc.). 
     It will be appreciated that the stand  114  presents an overall rectangular, box-like configuration. As previously indicated, the stand  114  also presents an open interior space  144  (see FIG. 3) that is configured to receive the bag support rack  12 . The generally open front of the stand  114  facilitates movement of the rack  12  into and out of the interior space  144 ; that is, the rack  12  may be moved generally horizontally toward the rear of the stand  114 . The rack  12  is typically moved through the open front and then dropped downwardly until the frame-supporting members  130  and  132  catch the outer bars  86  and  90  of the frame  28 . The base  26  is then permitted to shift downwardly by gravity until it engages the beams  134 , 136 , 138 , 140 . The bag  16  is consequently suspended from the frame  28  so that the weight of the material contained within the bag  16  is at least substantially removed from the base  26  (see FIG.  5 ). 
     The operation of the illustrated bag storage and unloading system  10  should be apparent from the foregoing description. Thus, it shall be sufficient to explain that the bag  16  is placed on the base  26  and attached to the frame  28  by the chain assemblies  102 , 104 , 106 , 108 , preferably when the rack  12  is in the storage condition (as shown in FIG.  4 ). The bag  16  is thereafter moveable without requiring user contact or direct handling of the bag  16 . It is also noted that the inverted U-shaped channel members  44  and  46  are conveniently configured to accept the forks of a standard forklift (not shown) for simplifying movement of the rack  12  and supported bag  16 . If desired, the rack  12  and supported bag  16  may be stacked with other racks as shown in FIG.  7 . 
     When it desired to unload the contents of the bag  16 , the rack  12  is coupled with the unloading station  14  by moving the rack  12  through the open front of the stand  114  and into the interior space  144 . It is noted that proper fore-and-aft placement of the rack within the stand  114  is facilitated by the vertical plate  128  which serves to limit rearward movement of the rack  12 . As shown in FIG. 5, the rack  12  is properly oriented within the stand  114  when the rear margin of the frame  28  engages or is just in front of the plate  128 . The rack  12  is subsequently dropped (e.g., by lowering the forks of the forklift) until the outer bars  86  and  90  of the frame  28  are caught by the respective frame-supporting members  130  and  132 . The forks of the forklift may then be removed, and the base  26  will shift downwardly by gravity until it engages the beams  134 , 136 , 138 , 140 . At this point, the bag  16  is suspended from the frame  28  and material may now be discharged through the bottom end  22  and into the hopper  142 . Once the bag  16  is empty, the rack  12  is lifted from the stand  114  preferably by inserting the forks of the forklift under the base  26 . This will normally cause the rack  12  to vertically collapse (until the sleeves  76 , 78 , 80 , 82  engage the platform  30 ) and the frame  28  will eventually be removed from the frame-supporting members  130  and  132 . The empty bag may be removed from the rack  12  and the rack  12  may then be reused to support a new bag, or the empty bag may alternatively be refilled on the rack  12 . 
     The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
     The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.