Patent Publication Number: US-10759059-B2

Title: Automated bin packing tool method

Description:
This application is a divisional of and claims priority to U.S. application Ser. No. 15/437,292 filed on Feb. 20, 2017, which is fully incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates generally to automated systems for packing items into containers, more specifically to an automated bin packing tool, and most specifically to an automated tool for lifting bagged produce from a conveyor and stacking the bagged produce into a transport bin. 
     Description of Related Art 
     Recent advancements in automated systems for processing food such as harvested vegetables, particularly root and tuber crops, allow for localized cleaning and packaging of the produce at the harvesting site, rather than having harvested produce shipped by truck or train to a remote processing facility. Produce packaged locally can be shipped directly to grocery stores to simplify the supply chain and thereby lower the average sales price of the produce. To promote farm-to-market supply on a large scale, specialized bulk bins have been developed for containing and transporting packaged produce in consumer-ready form, such as a 10-lb sack of potatoes. 
     Bins for transporting produce from farm to market come in many shapes and sizes, and are made from many different materials. One such bin that is particularly well-suited for farm-to-market transport of produce is the “bulk bin” made from heavy-duty cardboard.  FIG. 1  shows a typical bulk bin that is made from multi-walled corrugated cardboard. The bulk bin is formed in an octagonal configuration, having approximate dimensions of 46 in.×38 in.×36 in. These bulk bins have a load capacity of about 1300 lbs, and are designed for attachment to a wooden shipping pallet. If properly loaded, each bulk bin can safely contain up to 100 of the 10-lb sacks of potatoes. A cardboard cover can be placed over the bin, and so loaded, the palletized bin can be carried by forklift to a truck and delivered straight to market. 
     Loading the bulk bin is a manual process that is time-consuming and fraught with ergonomic risk. Workers are required to repeatedly lift produce sacks weighing 10 lbs. or more off a conveyor, like the one shown in  FIG. 2 , and carry them to the bulk bin. To properly load the bin, a worker must reach into the bin and place each sack individually to form a stack of overlapping rows of offset sacks, much like a pattern of mortared bricks, as shown in the cross-sectional view of  FIG. 3 . Over time, the worker who repeatedly stacks bulk bins in this fashion runs the risk of developing hand, arm, and back injuries. 
     Previous attempts to automate the process of loading containers for shipment are not suitable for loading bagged produce into bulk bins. One such automated system is designed to stack packages in a predetermined spatial arrangement for formation of a stack composed of different-sized packages. The packages run down a conveyor to a stacking site where horizontal pushers position each package first in a Z direction and then in an X direction onto a flat support, which can be raised and lowered in a Y direction to receive each package at its predetermined location. When the stack is completed, the packages must be stabilized to the support by film-wrapping, nets, or straps. While this system is effective for stacking rectangular packages of known dimensions, it cannot be used for loading a bulk bin with produce sacks whose shapes tend to deform according to how they are handled and stacked. The walls of the bulk bin would interfere with the horizontal pushers, or the bags would need to be pushed over the wall of the bin and fall to the bottom. This action would damage the produce and result in uneven and inaccurate stacking. 
     Another known system for automated package handling utilizes robotic arms equipped with vacuum carrying units and grippers that are designed to handle and stack different-sized packages. The system is designed to handle only smooth-sided packages that can withstand the mechanical force of its grippers and against which vacuum pressure may be drawn. The system is not suitable for loading a package with deformable sacks of produce prior to handling the package. Other known systems for loading pallets use automated conveyors and handling units to stack pallets with different-sized cartons to ensure even distribution of weight. These systems operate on prefilled cartons of generally rectangular dimensions that are loaded onto the conveyors in a predetermined sequence. The systems are not designed to load and stack deformable-shaped sacks into the cartons themselves. 
     What is needed is an automated scheme for efficiently loading a bulk bin with deformable containers that ensures an even distribution of weight within the bin without damaging the contents of the containers. 
     SUMMARY OF THE INVENTION 
     The present invention achieves the objective for automatically loading a bin with filled deformable containers being conveyed along horizontal rollers. The invention assembles a stack of multiple overlapping rows of such containers into the bin in a spatially efficient manner that ensures even distribution of weight throughout the bin so that the bin is ready for shipment. 
     In one embodiment, a method for loading into a bin an object such as a filled deformable container conveyed along horizontal rollers includes steps for positioning a plurality of parallel rods between and parallel to the horizontal rollers, raising the parallel rods when the object is conveyed to a loading position above the parallel rods, moving the parallel rods horizontally to a predetermined position above the bin, and rotating the parallel rods about a horizontal axis through a predetermined angle to allow the object to slide downward along the parallel rods and into the bin under force of gravity. 
     In another embodiment, a system for automatically loading into a bin an object such as a filled deformable container conveyed along horizontal rollers includes a movable support structure having a coupling end configured for attachment to a motive force, and having a lifting end supporting a plurality of parallel rods. The system includes a means for positioning the plurality of parallel rods between and parallel to the horizontal rollers, a means for raising the parallel rods when the object is conveyed to a loading position above the parallel rods, a means for moving the parallel rods horizontally to a predetermined position above the bin, and a means for rotating the parallel rods about a horizontal axis through a predetermined angle to allow the object to slide downward along the parallel rods and into the bin under force of gravity. 
     Whether implemented as a system or method, the invention automatically transfers an object such as a filled deformable container being carried along a conveyor into a bulk bin to form within the bin a stack consisting of multiple overlapping rows of offset containers. As each upper, overlapping row is placed onto a lower row, a vertical column of overlapping rows of offset containers is formed, with each overlapping row being at a different elevation in the column. The completed stack consists of side-by-side columns of overlapping rows of offset containers. This provides an efficiently packed and self-stabilizing formation because under force of gravity each upper container merges into the offset spacing created between adjacent lower containers. 
     An automated bin packing tool according to the present invention is adapted to transfer filled deformable containers from a conveyor having a general construction that includes a plurality of spaced-apart parallel horizontal rollers distributed along a conveying surface. The tool may be composed primarily of rigid parts, such as steel, aluminum, or hard plastic that are molded, machined, or extruded, and these parts are interconnected by conventional fasteners. 
     The tool includes a movable support structure that has a coupling end and a lifting end. The coupling end may be located at the top of the support structure, and may be configured for attachment to a prime mover or other motive force such as a robotic arm configured to raise, lower, translate, and rotate the entire tool. The coupling end of the tool may include an upper plate having multiple bolt holes for facilitating attachment to the external motive force. The moveable support structure may also include an interconnected framework for supporting all components of the tool, including one or more static guide plates, one or more hinged guide plates, and one or more actuators. 
     The lifting end may be located at the lower end of the tool. The lifting end supports a plurality of parallel rods. Each of the parallel rods may be coupled perpendicularly, as a cantilever, to an axle. The parallel rods are configured to bear the load of an object such as a filled deformable container that contains produce. Each parallel rod has a length approximately equal to or greater than the deformable width of the filled deformable container. The diameter of each parallel rod, and the spacing between each parallel rod, is configured to allow the parallel rods to be positioned between and parallel to the horizontal rollers of a conveyor from which the tool is designed to lift the filled deformable container. 
     The axle is coupled at one end to a pivot point of a cam. At an opposite end of the axle, one or more bearings allow the axle to rotate in the axis of the pivot point in response to linear actuation of the cam by a pneumatic cylinder that is mounted to the framework of the moveable support structure and coupled to the cam. So configured, actuation of the pneumatic cylinder causes rotation of the parallel rods about the pivot point axis. 
     In one embodiment, the tool may be constructed to limit rotation of the parallel rods between a loading position at one rotational extreme and an unloading position at an opposite rotational extreme. In the loading position, the parallel rods are rotated until they are oriented substantially horizontally. In the unloading position, the parallel rods are rotated downward to a predetermined angle of about 60 degrees. The loading position and the unloading position may correspond, respectively, to the pneumatic cylinder being fully extended and to the pneumatic cylinder being fully retracted. 
     The static guide plate extends downward from the a central portion of the framework and provides structural support for other components of the tool, such as the actuators and the bearings that support the axle. The static guide plate includes a corrugated lower edge that consists of a wave-like pattern of regularly spaced corrugations, each forming a curved circular cutout in the lower edge. The plate is configured so that the spacing and diameter of the corrugations correspond to the spacing and diameter of the horizontal rollers on the conveyor from which the tool retrieves the filled deformable containers. The tool is configured so that when the axle is installed between the bearings and cam, the parallel rods when rotated to the loading position will extend beneath the lower edge at a location offset from the corrugations. In operation, the tool is lowered by the robotic arm so that the corrugations of the static guide plate coincide with the horizontal rollers. With the horizontal rollers so aligned within the corrugations, the parallel rods align properly within the interstices of the rollers. 
     The hinged guide plate may include a static portion and a moveable portion. The static portion may be fastened to the framework, and coupled by a hinge to the static portion. An actuator is configured to cause rotation of the moveable portion about the hinge. A moveable shaft emerging from one end of the actuator is connected to a hinge bracket, while the opposite, static end of the actuator is fixed to the framework. So configured, actuation of the pneumatic cylinder imparts linear motion to the shaft, causing the moveable portion of the hinged guide plate to rotate about the axis of the hinge. 
     In one embodiment, the tool is constructed to limit rotation of the moveable portion of the hinged guide plate between an open position and a closed position. In the closed position, the moveable portion lies in a vertical plane, directly beneath the static portion. In the open position, the moveable portion is rotated to outward to a predetermined angle of about 30 degrees to widen distance between the moveable portion and the static guide plate. In another embodiment, the lower edge of the moveable portion of the hinged guide plate may include one or more corrugations similar in shape and purpose to the corrugations on the static guide plate. 
     In another embodiment the tool is configured for dual loading. This embodiment includes a pair of static guide plates, which are separated by a central space wherein the axles, pivot arms, and other linkage are mounted. A hinged guide plate is mounted opposite each static guide plate to form lifting two areas, one on either side of center. Each of the two lifting areas is serviced by a static guide plate, a hinged guide plate, a set of actuators, and a set of parallel rods. 
     In an initial state of operation the tool configured for dual loading is lowered to a predetermined position above the conveyor where the corrugations align with the horizontal rollers. The parallel rods in both lifting areas are set to the horizontal loading position so that the rods lie between and parallel to the rollers. The hinged guide plates are set to the closed position. The next state is a ready state, in which the hinged guide plates are set to the open position for receiving a filled deformable container into each loading area. 
     When the containers are conveyed into position within the loading areas, the hinged guide plates are set to the closed position to securely maintain the containers within the loading areas above the parallel rods. The tool may then be raised above the conveyor, thereby raising the parallel rods through the horizontal rollers and providing a carriage for the containers. 
     The tool with its container load is then moved horizontally by means of the robotic arm to a predetermined position above the bin. When the tool reaches the predetermined position, the parallel rods are rotated about a horizontal axis through a predetermined angle to the unloading position. This action allows the filled deformable container to slide downward along the parallel rods under force of gravity and into the bin. The predetermined position changes for each horizontal moving step so that the bin may be loaded in a predetermined sequence that builds a stack of containers within the bin in a desired configuration. In another embodiment of the invention, a predetermined packing sequence for the tool may be programmed to include a step for lowering the parallel rods to a predetermined height above the stack after the tool has been moved horizontally to the predetermined position. 
     After the tool has been unloaded, final movement steps are performed to return the tool to the ready state above the conveyor where it can retrieve the next container load. The final movement steps may include a combination of vertical and horizontal moves, and may further include a step for rotating one or more hinged guide plates to the open position. The tool may then be moved again through the sequence of states for loading and unloading containers, changing only the predetermined position from which a container is packed into the bin. In one embodiment, each predetermined position is offset from an immediately previous predetermined position to create spacing between adjacent containers that slide into the bin. When containers are unloaded to form higher layers in the stack, the position of the unloading points for the higher layer are offset from the unloading points for the lower layer, so that containers drop substantially centrally onto the spacing. The deformable property of each container allows a portion of each higher level container to merge or settle into the offset spacing between adjacent lower level containers. By exploiting this property, a tool according to the invention can automatically assemble a stack of multiple overlapping rows of offset sacks into bulk bins in a spatially efficient manner that ensures even distribution of weight throughout the bin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. Component parts shown in the drawings are not necessarily to scale, and may be exaggerated to better illustrate the important features of the invention. Dimensions shown are exemplary only. In the drawings, like reference numerals may designate like parts throughout the different views, wherein: 
         FIG. 1  is a perspective view of a bulk bin, known in the prior art, that can be used for containing and transporting produce directly from farm to market. 
         FIG. 2  is a perspective view of a conveyor with horizontal rollers, known in the prior art, shown with two rows of three potato sacks spaced along the conveyor. 
         FIG. 3  is a front cross-sectional view of bulk bin containing overlapping rows of produce sacks stacked like bricks in an offset pattern known in the prior art. 
         FIG. 4  is an exploded perspective view of an automated bin packing tool according to one embodiment of the present invention. 
         FIG. 5  is a top view of the automated bin packing tool of  FIG. 4 . 
         FIG. 6  is a cross-sectional frontal view of the automated bin packing tool taken along section B-B of  FIG. 5 . 
         FIG. 7  is a cross-sectional rear view of the automated bin packing tool taken along section E-E of  FIG. 5 . 
         FIG. 8  is a frontal view of the automated bin stacking tool of  FIG. 4 . 
         FIG. 9  is a cross-sectional side view of the automated bin packing tool taken along section C-C of  FIG. 8 . 
         FIG. 10  is a cross-sectional side view of the automated bin packing tool taken along section D-D of  FIG. 8 . 
         FIG. 11  is a perspective view of one embodiment according to the invention of a bin packing tool in an initial state positioned above a conveyor having horizontal rollers. 
         FIG. 12  is a perspective view of the automated bin packing tool of  FIG. 11  in a ready state of use as two sacks of produce are conveyed within reach of the tool, with hinged guide plates moved to an open position. 
         FIG. 13  is a perspective view of the bin packing tool of  FIG. 12  in a later state of use, showing the tool lifting the two produce sacks above the conveyor, with hinged guide plates in a closed position. 
         FIG. 14  is a cross-sectional side view of a bulk bin being loaded by an automated bin packing tool according to the invention. 
         FIG. 15  is another cross-sectional side view of a bulk bin being loaded by an automated bin packing tool according to the invention. 
         FIG. 16  is a top view of an octagonal bulk bin containing stacked rows of produce sacks in a pattern wherein sacks in the front and rear rows are oriented 90 degrees with respect to sacks in all other rows. 
         FIG. 17  is a top view of an octagonal bulk bin showing a superimposed pattern of target points at each of which an automated bin packing tool unloads packaged produce in a predetermined sequence according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     This disclosure presents exemplary embodiments of an invention for automatically loading a bin with objects that are being conveyed along horizontal rollers. The invention may be implemented in the form of a system or method, and is particularly useful for loading deformable containers such as consumer-ready sacks of produce, e.g., potatoes, onions, apples, etc., into bulk bins in a spatially efficient manner that ensures even distribution of weight throughout the bin. Embodiments described herein illustrate use of the invention for loading into the bin filled deformable containers such as produce sacks; however, the invention has equal utility for loading a wide variety of objects from a conveyor into a bin, including but not limited to many shapes and sizes of rigid containers, raw materials, and unpackaged manufactured products. 
     With reference again to  FIGS. 1-3 , in one implementation of the invention a system or method disclosed herein automatically transfers filled deformable containers  201  (e.g. sacks of produce) being carried along a conveyor  202 , into a bulk bin  103  to form within the bin a stack  300  consisting of multiple overlapping rows  303  of offset containers  201 . This pattern of overlapping rows of offset containers resembles in cross section the familiar pattern made by bricks set within a mortared wall. As each upper overlapping row is placed onto a lower row, a vertical column of overlapping rows of offset containers is formed, with each overlapping row being at a different elevation in the column. When filling the volume of the bin with deformable containers such as produce sacks, the bin may be filled most efficiently, and the weight distributed most evenly, when the sacks are arranged in a stack consisting of side-by-side columns of overlapping rows of offset sacks. 
     As used herein, the term deformable container means a container that has a non-rigid outer surface capable of changing shape. In particular, the overall shape of the deformable container can change according to movement or displacement of items contained within the deformable container that push against the outer surface. Nonlimiting examples of deformable containers are plastic bags, burlap sacks, and cloth bags. As discussed herein, a sack of produce such as the 10-lb sack of potatoes is an example of a filled deformable container. Depending on its contents, a filled deformable container tends to assume the general shape of the surface on which it rests. It should be appreciated that the side-by-side columns of overlapping rows of offset sacks as described in the preceding paragraph provide an efficiently packed and self-stabilizing formation for stacking filled deformable containers because under force of gravity each upper sack merges and settles into the offset spacing created between adjacent lower sacks. 
     The present invention is adapted to transfer filled deformable containers  201  from a conveyor  202  having a general construction that includes a plurality of spaced-apart parallel horizontal rollers  204  distributed along a conveying surface  206 . Such conveyors are well known in the art and are manufactured in a variety of configurations. For example, one size conveyor has 1 ⅜ in. diameter rollers spaced apart on 3.0 in. roller centers, mounted in steel frames. A heavier duty conveyor of similar construction has 1.9 in. diameter rollers spaced apart on 6.0 in. roller centers. The invention may be adapted dimensionally to interface with any and all sizes of conveyors having this general construction. 
       FIG. 4  shows an exploded perspective view of an automated bin packing tool  400  according to one embodiment of the present invention.  FIGS. 5 to 10  show different views of the same embodiment, to shed further light on the following discussion. The automated bin packing tool  400  may be composed primarily of rigid parts, such as steel, aluminum, or hard plastic that is molded, machined, or extruded, and these parts are interconnected by conventional fasteners suitable for the purpose. Generally speaking, the tool  400  includes a movable support structure  408  that has a coupling end  410  and a lifting end  412 . The coupling end  410  may be located at the top of the support structure  408 , and may be configured for attachment to a prime mover or other motive force having energy sufficient to raise, lower, translate, and rotate the entire tool. Accordingly, the coupling end  410  of tool  400  may include an upper plate  411  having bolt holes defined therethrough or other means thereon for facilitating attachment to the external motive force. The moveable support structure  408  may also include an interconnected framework  413  for supporting all components of the tool, including one or more static guide plates  414 , one or more hinged guide plates  415 , and one or more actuators  430 . 
     In one embodiment, the motive force attachable to the coupling end  410  comprises a robotic arm (not shown). Robotic arms are well known in the manufacturing arts and may be programmed by means of a programmable logic controller to effect precision positioning of tools for performing repetitive tasks. As such, no further description of robotic arms or programmable logic controllers is provided herein. It should be appreciated however, that such a robotic arm coupled to a system according to the invention may form part of the means for positioning, raising, moving, or rotating parallel rods  416 , as further described below. 
     The lifting end  412  may be located at the lower end of the tool  400 . The lifting end  412  supports a plurality of parallel rods  416 . Each of the parallel rods  416  may be coupled perpendicularly, as a cantilever, to an axle  418 . The parallel rods  416  should be configured for sufficient strength to withstand the load of a filled deformable container  201  that the tool  400  is designed to lift. Each parallel rod  416  should have a length sufficient to support a container  201 , for example, a length approximately equal to or greater than the deformable width of a container  201  that is being carried along the conveyor  202 . In addition, the diameter of each parallel rod  416 , and the spacing between each parallel rod  416 , should be configured to allow the parallel rods to be positioned between and parallel to the horizontal rollers  204  of a conveyor  202  from which the tool  400  is designed to lift a filled deformable container  201 . That is, each parallel rod  416  should have a diameter less than the spacing between any two adjacent horizontal rollers  204  to allow the parallel rods to be lowered together through the interstices of the rollers  204 , extending substantially parallel to the rollers  204 , to a position below the conveying surface so that the rods  416  do not interfere with containers  201  being conveyed along the rollers  204 . The spacing between each parallel rod  416  may be the same as the spacing between horizontal rollers (e.g. one rod per roller), or the spacing between each parallel rod  416  may be greater than the spacing between horizontal rollers (e.g. one rod for every three rollers). In other embodiments, the parallel rods  416  may be evenly spaced (i.e. equal spacing between any two adjacent rods) or unevenly spaced (i.e. spacing between two adjacent rods unequal to the spacing between at least one other pair of adjacent rods). 
     The axle  418  is coupled at one end to a pivot point  420  of a cam  422 . At an opposite end of the axle  418 , one or more bearings  424  allow the axle to rotate in the axis of the pivot point in response to linear actuation of the lobe  426  of cam  422 . The lobe  426  of the cam  422  may be actuated, for example, by a shaft  428  of an actuator  430  (e.g., a pneumatic cylinder  430 ) that is mounted to the framework  413  of the moveable support structure  408  and coupled to the lobe  426 , as shown. So configured, actuation of the pneumatic cylinder  430  causes rotation of the parallel rods  416  about the pivot point axis. One example of a pneumatic cylinder suitable for this purpose is a model 312-DXP made by the Bimba Manufacturing Co. 
     In one embodiment, the tool  400  may be constructed to limit rotation of the parallel rods  416  between a loading position  432  at one rotational extreme and an unloading position  434  at an opposite rotational extreme. In the loading position  432 , the parallel rods  416  are rotated until they are oriented substantially horizontally. In the unloading position  434 , the parallel rods are rotated downward to a predetermined angle of about 60 degrees with respect to the horizontal. The loading position  432  and the unloading position  434  may correspond, respectively, to the pneumatic cylinder  430  being fully extended and to the pneumatic cylinder  430  being fully retracted. Other embodiments are possible in which these relationships are reversed. 
     The static guide plate  414  extends downward from the framework  413  and occupies a substantially central position with respect to other parts of the tool  400 . The static guide plate  414  may provide structural support for other components of the tool, such as the actuators  430 , and the bearings  424  that support the axle  418 . In addition, the static guide plate  414  may include a corrugated lower edge  436 . The corrugated lower edge  436  consists of a wave-like pattern of regularly spaced corrugations  438 , each corrugation forming a curved circular cutout in the lower edge. The plate  414  is configured so that the spacing and diameter of the corrugations  438  correspond to the spacing and diameter of the horizontal rollers  204  on the conveyor  202  from which the tool  400  retrieves containers  201 . As best depicted in  FIG. 10 , the tool  400  is configured so that when the axle  418  is installed between the bearings  424  and cam  422 , the parallel rods  416  when rotated to the loading position  432  will extend beneath the lower edge  436  at a location offset from the corrugations  438 . In operation, the tool  400  is lowered by the robotic arm so that the corrugations  438  of the static guide plate  414  coincide with the horizontal rollers  204 , that is, each corrugation  438  partially surrounds the top surface of a roller  204 . With the horizontal rollers  204  so aligned within the corrugations  438 , the parallel rods  416  will align properly within the interstices of the rollers  204 . 
     The hinged guide plate  415  may include a static portion  440  and a moveable portion  442 . The static portion  440  may be fastened to the framework  413 , and coupled by a hinge  444  to the static portion  440 , as shown in  FIGS. 4 and 6 . An actuator  446  may be configured to cause rotation of the moveable portion  442  about the hinge  444 . For example, actuator  446  may be a pneumatic cylinder similar in construction to actuator  430 . A moveable shaft  448  emerging from one end of the actuator  446  may be connected to a hinge bracket  450 , while the opposite, static end of the actuator  446  may be fixed to the framework  413 , as shown. So configured, actuation of the pneumatic cylinder imparts linear motion to the shaft  448 , causing the moveable portion  442  of the hinged guide plate  415  to rotate about the axis of hinge  444 . 
     In one embodiment, the tool  400  may be constructed to limit rotation of the moveable portion  442  between an open position and a closed position. In the closed position, the moveable portion  442  lies in a vertical plane, directly beneath the static portion  440 , as illustrated in  FIG. 11 . In the open position, illustrated in  FIG. 12 , the moveable portion  442  is rotated to outward to a predetermined angle to widen distance between the moveable portion  442  and the static guide plate  414 . In one embodiment, the predetermined angle is about 30 degrees with respect to the vertical. Other embodiments having a different predetermined angle are possible, and the angle may vary according to the distance between the moveable portion  442  and the static guide plate  414  that is required to permit passage of a particular container  201  therethrough. In another embodiment, the predetermined angle is selectable and can range between zero degrees in the closed position and about 45 degrees in the fully open position. 
     In one embodiment of the invention, as shown in  FIG. 4 , the lower edge  451  of the moveable portion  442  of the hinged guide plate  415  may include one or more corrugations  452 . The corrugations  452  may be similar in shape and purpose to the corrugations  438  on static guide plate  414 , and may assist in properly aligning the tool  400  to the conveyor  202 . 
     Various accessories may also be mounted to the tool  400  to effect or assist with control and operation of the tool. Again with reference to  FIG. 4 , one such accessory may be a control valve mounting assembly  454  coupled to the framework  413  at a convenient location. The mounting assembly  454  may be used, for example, in an embodiment of the tool  400  that utilizes pneumatic cylinders to function as the actuators  430  or  446 . One or more solenoid valves  456  may be mounted within the mounting assembly  454 , and connected via pneumatic tubing between the actuators  430 ,  446  and a source of compressed air (not shown). The solenoid valves  456  are connected electrically to a power supply through the programmable logic controller or another control scheme according to methods well known in the art to enable fully automatic control, or a combination of manual and automatic control, of the actuators  430 ,  446 . Another accessory, flanged conduit  458 , may be connected between the upper plate  411  and the framework  413 , through which electrical or pneumatic lines, or both, may be run for powering the actuators  430 ,  446 . The flanged conduit  458 , by mechanical connection, may also form part of the means for positioning, raising, moving, and rotating the parallel rods  416 . Brackets such as  459  may be attached to the upper plate  411  or framework  413 , for mounting accessories or for routing pneumatic or electrical lines. 
     The embodiment of the present invention shown throughout  FIGS. 4 to 15  is configured for dual loading. This embodiment includes a pair of static guide plates  414 , which are separated by a central space  462  wherein the axles  418 , pivot arms  422 , and other linkage are mounted. A hinged guide plate  415  is mounted opposite each static guide plate  414 , to form lifting two areas  464  and  466  to either side of center, as shown. Thus, each of the two lifting areas is serviced by a static guide plate  414 , a hinged guide plate  415 , a set of actuators  430 , an actuator  446 , and a set of parallel rods  416 , all of which operate as heretofore described. 
     Operation of the tool  400  according to the present invention is now described with further reference to  FIGS. 11 to 17 . Each of the movements described below may be effected by manual controls, or preferably automatically by the programmable logic controller executing an algorithm for precise positioning of the tool  400 . The precise locations of the conveyor  202  and bin  103  may be registered in the programmable logic controller during an initialization procedure to ensure accurate collection of containers  201  from the conveyor  202  and placement of the containers  201  within the bin  103 . Once the system is initialized, the programmable logic controller outputs its control signals to the robotic arm, which moves the tool  400  through a sequence of predetermined positions or states. The programmable logic controller may output additional control signals to the actuators  430 ,  446  to cause movement of the parallel rods  416  or hinged guide plates  415  depending on the state of the tool. 
       FIG. 11  shows the tool  400  in an initial state above the conveyor  202 . Here, the tool  400  has been lowered to a predetermined position where the corrugations  438  and  452  align with the horizontal rollers  204 . In this state, the parallel rods  416  in both lifting areas  464 ,  466  are set to the horizontal loading position  432  so that the rods  416  lie between and parallel to the rollers  204 . Also in the initial state, the hinged guide plates  415  are set to the closed position. The next state is a ready state, in which the hinged guide plates  415  are set to the open position, as shown in  FIG. 12 . In this state the tool  400  is ready to receive a filled deformable container  201  into each of its loading areas. In one embodiment, conveyance of a container into a loading area may be sensed by automatic means, such as by a position sensor, and a corresponding sensory signal sent as feedback to the programmable logic controller signaling that the tool is ready for movement to the next state. 
     When the containers  201  are conveyed into position within the loading areas  464 ,  466 , the hinged guide plates  415  are again set to the closed position, to securely maintain the containers  201  within the loading areas above the parallel rods  416 . As shown in  FIG. 13 , the tool  400  may then be raised above the conveyor  202 . This action raises the parallel rods  416  through the horizontal rollers  204 , providing a carriage for containers  201 . The parallel rods  416  are preferably raised to a predetermined height above the conveyor  202  that is also higher than the bin  103  into which containers  201  are to be stacked by the tool  400 . 
     The tool  400  with its container load supported by parallel rods  416  and secured between guide plates  414 ,  415  is then moved horizontally by means of the robotic arm or other motive force to a predetermined position above the bin  103 .  FIG. 14  shows a cross-sectional side view depicting a bulk bin  103  being packed by the tool  400  by unloading lifting area  466  at the predetermined position. When the tool reaches the predetermined position, the parallel rods  416  are rotated about a horizontal axis through a predetermined angle, as described above, to the unloading position  434 . This action allows the filled deformable container  201  to slide downward along the parallel rods  416  under force of gravity and into the bin  103 . The predetermined position will typically change each time the horizontal moving step is performed, so that the bin  103  may be loaded in a predetermined sequence that builds a stack of containers  201  within the bin  103  in a desired configuration. If the tool  400  is configured with a second lifting area  464 , rotation of the corresponding second set of parallel rods  416  may occur at the same predetermined position, or after further movement of the tool  400  to a subsequent predetermined position, depending on the loading scheme of the predetermined sequence. FIG.  15  shows a cross-sectional side view of the bulk bin  103  being packed by the tool  400  by unloading lifting area  464  at the same predetermined position depicted in  FIG. 14 . 
     In another embodiment of the invention, a predetermined packing sequence for the tool  400  may be programmed to include a step for lowering the parallel rods, i.e. lowering the tool  400 , to a predetermined height above the stack after the tool has been moved horizontally to the predetermined position. Such a step may be desirable, for example, to improve placement accuracy of a container  201  or to limit the distance that a container  201  must drop before it reaches its position in the stack to avoid damaging the contents of the container. 
     After the tool  400  has been unloaded, final movement steps are performed to return the tool  400  to the ready state above the conveyor  202  where it can retrieve the next container load. The final movement steps may include a combination of vertical and horizontal moves, and may further include a step for rotating one or more hinged guide plates  415  to the open position. The tool  400  may then be moved again through the sequence of states for loading and unloading containers, changing only the predetermined position from which a container is packed into the bin. In other words, after the loaded parallel rods are moved horizontally to the first predetermined position above the bin  103  and unloaded, the tool is returned to the ready state, the sequence of steps for positioning and raising the parallel rods is repeated, and the parallel rods are moved horizontally to a subsequent predetermined position above the bin to unload a container at the next location in the stack. 
     The predetermined sequence for packing a bin  103  may vary according to the size and configuration of the bin  103 , the size, configuration, and number of containers  201 , and by the desired geometry of the stack. A tool  400  according to the invention may be employed to achieve any number of different stacking configurations. By way of example, one such stacking configuration is depicted in  FIG. 16 . This figure shows a top view of an octagonal bulk bin  103  containing stacked rows of filled deformable containers  201  in a particular pattern. This pattern may be used, for example, for packing a bulk bin with 10-lb sacks of potatoes. In this example, there is a front row  470  where containers  201  lie end-to-end, there are middle rows  472  where more containers  201  lie side-by-side, and there is a rear row  474  where more containers  201  lie end-to-end. Thus, the containers in the front and rear rows are oriented 90 degrees with respect to the containers in the middle rows. Each container  201  has been packed into the bin  103  after being dropped by the tool  400  from a different predetermined position above the bin in a predetermined sequence, where each predetermined position is offset from an immediately previous predetermined position to create spacing  476  between adjacent containers that slide into the bin. In one embodiment designed for packing 10-lb sacks of potatoes, the spacing  476  is about 6 to 8 inches. In operation, to effect the 90-degree change in orientation between containers lying end-to-end and containers lying side-by-side, the tool  400  must undergo an additional movement step. In this additional step, after the parallel rods  416  are moved horizontally to the predetermined position above the bin  103 , the rods  416  are then rotated within a horizontal plane about a vertical axis. In this example, the angle of rotation is 90 degrees, however, the angle may be varied to achieve any desired placement pattern. 
       FIG. 17  illustrates one example of a pattern of predetermined positions at each of which a tool  400  unloads filled deformable containers  201  in a predetermined sequence according to one embodiment of the invention. The pattern of predetermined positions, which consists of rows of numbered and lettered circles and squares, is shown superimposed onto an octagonal bulk bin  103 . An imaginary X-Y plane is depicted in the lower left-hand corner of the figure. The origin of the X-Y plane may be registered with the programmable logic controller as a reference point from which all predetermined positions are located, for example, as end points for directing movement of the robotic arm when moving parallel rods  416  of tool  400  horizontally to the predetermined positions. 
     In the exemplary sequence modeled in  FIG. 17  there are circles and squares. Each circle and square indicates a predetermined position, or unloading point, at which a set of parallel rods  416  unloads a filled deformable container  201  into the bin  103 . The circles indicate an unloading point on a lower layer of the stack. The squares indicate an unloading point on a higher layer of the stack that rests on top of the lower layer. Each circle and square also has an arrow pointing away from the circle or square in one direction. The arrow indicates the direction toward which a filled deformable container  201  slides off a set of parallel rods  416 . A letter within a circle or square denotes the unloading order according to the sequence, which is carried out in alphabetical order, wherein all unloading occurs first at the upper case letters before continuing with lower case letters. A number within a circle or square indicates which of multiple loading areas in a single tool is to be unloaded at the unloading point. In this example, the tool  400  is configured with dual loading areas  464  and  466 . The number 1 in A 1  corresponds to a first loading area  464  and the number 2 in A 2  corresponds to a second loading area  466 . 
     The unloading sequence therefore begins at points A 1  and A 2  near the upper left-hand corner of the bin. The tool  400 , configured with dual loading areas, is moved horizontally above the bin until the parallel rods  416  of the first loading area reach unloading point A 1  and the parallel rods  416  of the second loading area reach unloading point A 2 . There, the rods  416  are rotated downward, causing the filled deformable containers  201  to slide off the rods—to the left of A 1  and to the right of A 2 —and into the bin so that the containers  201  are oriented side-by-side and separated by the desired spacing  476 . The sequence then continues. The tool  400  returns to the conveyor to fetch more containers, moves the two sets of parallel rods to unloading points B 1 -B 2 , and drops the containers at those locations. The sequence is repeated in the same manner, dropping containers at C 1 -C 2 , then D 1 -D 2 , E 1 -E 2 , F 1 -F 2 , G 1 -G 2 , H 1 -H 2 , I 1 -I 2 , J 1 -J 2 , K 1 -K 2  and L 1 -L 2 , forming a lower layer of containers in a 4×6 array. Then a final row is unloaded on the right-hand side of the bin  103  to complete the 5×6 array at the lower level of middle rows  472 . In the final row, the containers are dropped one at a time in the order M 1 , M 2 , N 1 , N 2 , O 1 , and O 2 . This order requires that, after unloading a container from a first set of parallel rods  416  at an unloading position M 1 , N 1 , or O 1 , the tool  400  configured for dual loading must be repositioned by horizontal movement and by a 180-degree horizontal rotation to position the second set of parallel rods  416  at the unloading position M 2 , N 2 , or O 2  to unload the second container. 
     The unloading sequence then continues, to pack the bin  103  with a rear row  474  of containers at unloading points P 1 , P 2 , Q 1 , and Q 2 , and with a front row  470  of containers at unloading points R 1 , R 2 , S 1 , and S 2 . In the front and rear rows  470  and  474 , the containers  201  are oriented end-to-end, rather than side-to-side as in the middle rows  472 . The parallel rods  416  that carry containers  201  into rows  470  and  474  are therefore rotated an additional 90 degrees in a horizontal plane above the bin  103  prior to dropping the containers. When a container is dropped at unloading point S 2 , the lower layer of the stack is completed. 
     The unloading sequence then continues to create the next or higher layer in the stack. The unloading sequence for the higher layer is similar to the unloading sequence for the lower layer, except that the position of the unloading points for the higher layer are offset from the unloading points for the lower layer. The unloading points for the higher layer are indicated by the squares. The higher layer sequence begins at unloading points a 1  and a 2 , where the loading areas  464 ,  466  of the tool  400  are moved to drop containers  201  from the two sets of parallel rods  416 . The container  201  dropped at a 1  falls onto spacing  476  between A 1  and A 2 , and the container  201  dropped at a 2  falls onto spacing  476  between A 2  and G 1 . The stack now has two lower adjacent filled deformable containers  201  at A 1  and A 2  separated by a spacing  476 , with an upper filled deformable container  201  at a 1  centered approximately onto the spacing. Likewise, the stack has two lower adjacent filled deformable containers  201  at A 2  and G 1  separated by a spacing  476 , with an upper filled deformable container  201  at a 2  centered approximately onto the spacing. The unloading sequence for the higher layer continues as indicated, causing tool  400  to drop containers onto each spacing  476  between adjacent containers on the lower layer. The deformable property of each container  201  allows a portion of each higher level container to merge or settle into the offset spacing between adjacent lower level containers. By exploiting this property, a tool according to the invention can automatically assemble a stack of multiple overlapping rows of offset sacks into bulk bins in a spatially efficient manner that ensures even distribution of weight throughout the bin. 
     Exemplary embodiments of the invention have been disclosed in an illustrative style. Accordingly, the terminology employed throughout should be read in a non-limiting manner. Although minor modifications to the teachings herein will occur to those well versed in the art, it shall be understood that what is intended to be circumscribed within the scope of the patent warranted hereon are all such embodiments that reasonably fall within the scope of the advancement to the art hereby contributed, and that that scope shall not be restricted, except in light of the appended claims and their equivalents.