Patent Publication Number: US-8530772-B2

Title: Document sorting machine

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 13/098,064, filed 29 Apr. 2011, titled “Document Sorting Machine,” which is hereby incorporated by reference for all purposes as if fully set forth herein. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to machines utilized to sort documents, i.e., mail pieces such as letters, and more particularly, to a sorting machine having dual magazines located at one end for increasing sorting capacity. 
     2. Description of Related Art 
     Automated sorting machines are well known in the art for sorting large volumes of documents (e.g. letters, postcards, checks, flats, and the like) into groups having a common identifying criteria (e.g. Zip Codes, mail boxes, and so forth). A sorting machine typically comprises a front end or feeder section and one or more stacker sections, wherein the front end feeds the documents, one-by-one, past a reader (e.g. optical character reader (“OCR”), bar code reader (“BCR”), or the like) to a transport that carries it to a designated sort pocket in one or more stacker sections. 
     As the document passes the reader, the desired criteria on the document is read and a signal is generated that, in turn, is processed to generate a designation signal for that particular document. This designation signal, in turn, triggers a diverter or gate at the designated pocket in the stacker section as the document approaches to divert the piece from the transport into the designated pocket where it is stacked with other pieces having the same identifying criteria. Such machines are well known and are commercially available e.g., Vsort® Fiat Sorting machine, NP8000™ Sorting machine, both manufactured and distributed by National Presort, Inc., Dallas, Tex. 
     Many present sorting machines are comprised of a plurality of vertically stacked tiers of sort pockets which increase the number of pockets available during the sorting operation without substantially increasing the machine&#39;s foot print (floor area required for the machine). With these types of sorting machines, the letters are read and directed by a Level Distribution Unit or elevator system to the particular tier on which its respective sort pocket is located. For example, if the sorting machine has four tiers, only approximately 25% of the letters being fed will go to each tier. This means that approximately 75% of the sort capacity of each tier goes unutilized. It can be seen that if the unused capacity on each tier can be reduced, the throughput of the machine can be significantly increased. 
     Although the foregoing developments represent strides in the area of sorting machines, many shortcomings remain. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The novel features believed characteristic of the invention are set forth in the appended claims. However, the invention itself, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a simplified side view of the sorting machine of the present invention can be incorporated; 
         FIG. 2  is a top view of the sorting machine shown in  FIG. 1 ; 
         FIG. 3  is an enlarged view of one end of the sorting machine of  FIG. 1 ; 
         FIG. 4  is an enlarged, top view of the buffer unit at each end of each tier of the sorting machine of  FIG. 1 ; 
         FIG. 5  is an enlarged, top view of the serpentine “piggy-backing” section at each end of the sorting machine of  FIG. 1 ; 
         FIG. 6  is a top view of an alternative embodiment of a sorting machine of the sorting machine of  FIG. 1 ; 
         FIG. 7  is side view of the sorting machine of  FIG. 6 ; 
         FIGS. 8 and 9  are side views of the sorting machine of  FIG. 6  with a purge system; 
         FIG. 10A  is a top view of a buffer unit and the purge system of the sorting machine of  FIG. 6 ; 
         FIG. 10B  is a top view of an alternative embodiment of the buffer unit and the purge unit of the sorting machine of  FIG. 10A ; 
         FIG. 11  is a plot diagram depicting a preferred method to sort documents; 
         FIGS. 12 and 13  are oblique view of a tray system operably associated with the sorting machine of  FIG. 6 ; 
         FIG. 14  is an oblique view of an alternative embodiment of a magazine of the sorting machine of  FIG. 6 ; 
         FIG. 15  is a top view of the magazine of  FIG. 14 . 
     
    
    
     While the sorting machine and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The document sorting machine of the present application overcomes common disadvantages associated with conventional machines and method for sorting documents. Illustrative embodiments are described below. It will of course be appreciated that in the development of any actual embodiment, numerous implementation-specific decisions will be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
     Referring more particularly to the drawings,  FIG. 1  is a plan view of a multi-tiered, document sorting machine  10  in accordance with the present invention. As seen in  FIG. 1 , machine  10  comprises of two halves A and B which are substantially identical in form and function. For the sake of clarity, only one half will be described in detail. Each half (A and B) is comprised of a feeder section  11 , a transport  12 , a serpentine piggy-backing section  13 , and elevator or Level Distribution Unit (LDU)  14 , and multi-tiered stacker section  15 . 
     Each half (A and B) comprises of a feeder section  11  having a magazine  16  (see  FIG. 2 ) onto which a batch of documents (e.g., letters or pieces  17 ) are positioned (see  FIG. 2 ). Conveyor  18  (e.g., motor driven chain-link belts) feeds documents  17  forward onto a pickoff which picks off one document at a time and delivers it onto transport  12 . As the document passes by optical character reader and/or bar code reader (not shown), an identifying mark (e.g. a sort code such as a Zip Code or bar code, respectively) on the document  17  is read by the appropriate reader which, in turn, generates a signal representative of the mark as is well known in the art. These signals are then processed to direct the document through LDU  14  to its pre-assigned sort pocket on one of tiers  22  in stacker section  15 . 
     Stacker section  15  is shown as being comprised of a plurality (e-g. four) of vertically stacked tiers  22 , each tier being substantially identical to the others. Each tier  22  has a plurality of horizontal stacker bins or “pockets”  20  (only some shown and numbered for clarity) arranged in pairs having one pocket on either side of the looped transport  12 . As best seen in  FIGS. 2 and 3 , transport  12  on each tier  22  forms a continuous path or “carousel” which extend through both the adjacent stacker sections  15  of both A and B. That is, transport  12  passes around a “turn around” pulleys  23  at the opposite ends of the respective stacker sections so that a document may be carried along one side of the sort pockets, turned around, and then back along the other side of the sort pockets until the document reaches its designated pocket. While only two stacker sections are shown, it should be recognized that there may be more than two section aligned with each other or the two sections shown may be combined into a single stacker section without departing from the present invention. 
     Each pocket  20  has a diverter means (see  21   a  in  FIG. 4 ; not shown in other Figures for the sake of clarity) which is actuated as a designated document  17  approaches its pocket. The diverter, when activated, temporarily intersects the centerline of transport  12  to thereby divert document  17  from transport  12  into its designated pocket  20 . This type of operation is well known in commercially-available sorting machines; e.g., Models NP8000, Vsort®, and OMEGA® Mail Sorters, manufactured and distributed by National Presort, Inc., Dallas, Tex. 
     While the machine  10  will be shown and described as having four tiers  22 , it should be recognized that more or less tiers (i.e., at least one) can be used without departing from the present invention. It will also be recognized, in most operations using multi-tiered sorting machines, the sorting of the mail will be programmed to arrange the sort pockets so that each tier will receive approximately an equal amount of the documents. For example, in a four-tier machine, the designated pockets for a particular batch of documents will be assigned so that approximately 25% of the documents will be fed to each tier, leaving appropriate 75% of the available transport capacity of that tier unused. 
     In accordance with one embodiment, dual feeders  11  feed documents onto transport  12  from opposite ends of the sorting machine  10 . That is, one feeder  11 A reads and feeds documents from one end of the sorter  10  through its respective LDU  14  to each of the four tiers  22  while, at the same time, feeder  11 B reads and feeds documents from the other end of the elongated sorting machine  10 . 
     As described above, documents  17  are fed from either feeder  11 A or  11 B and may have to travel almost all of the way around the looped transport  12  of a respective tier  22  in order to reach a designated pocket  20  which lies on the other side of the stacker section from which the document it entered the transport. In order to do this, that document must completely travel through both stacker sections  15  along one side of the tier and then reverse directions at “turn around” pulley  23  in a respective buffer unit  30  before it can travel along the other side of the tier to reach its designated pocket. 
     Since documents  17  are being fed simultaneously from both feeders  11 A and  11 B onto respective ends of the respective common looped transport  12  of each respective tier  22 , there is a real possibility that a document from one of the feeders and already in the transport may collide with a document being fed onto the transport by the other feeder; thereby causing a collision between the two documents. Any such collisions can result in a shut-down of sort operations. To prevent this from happening, a buffer unit  30  is provided at each end of each tier  22 . Since the buffer units  30  are identical, only the unit at one end (i.e.  30 B) will be described in detail. 
     As best seen in  FIG. 4 , buffer unit  30 B includes transport  12 B that feeds document  17 C from feeder  11 B into the looped or carousel transport  12  at one end of a respective tier  22 . To prevent document  17 C from colliding with document  17 B already on transport  12  (e.g., one which has been fed from feeder  11 A), a sensor(s) (not shown) along transport  12  determines when document  17 B is likely to arrive at the merge point  35  at the same time as document  17 C will enter transport  12 . If the possibility of collision is imminent, document  17 B is held in buffer unit  30  until document  17 C enters transport  12  at point  35 , at which time, document  17 B is released to resume normal operation. 
     If a following document  17 N is positioned on transport  12  so that it might run up onto the documents  17 B as it is being delayed in unit  30 , gate G is actuated to divert document  17 B into a “purge” pocket  20 P. Any documents in purge pocket  20 P are then removed and ran back through sorting machine  10  to sort them into their proper packets. This allows both feeders to continue to feed documents without interruption. 
     Another feature of the present invention is serpentine piggy-back unit  13  ( FIG. 5 ). The function of this unit is to stack, or “piggy-back” consecutive documents going to the same designated pocket whose combined thicknesses are equal to or less than a predetermined thickness. Stacking such documents is highly beneficial since it reduces the number of times a gate at a particular pocket has to be actuated during the sort operation. Also, the piggy-backing of these documents leaves a gap on the transport which is also beneficial in merging the documents from the dual feeders. 
     In the operation of serpentine, piggy-back unit  13 , the thickness of each document  17 D ( FIG. 5 ) is measured by any known thickness measuring device  40  as it passes through serpentine unit  13 . Such devices are well known in the art and are available from several commercial sources. If the thickness of document  17 D equals or exceeds a predetermined thickness, it passes on through unit  13  to its designated pocket in the stacker section. However, if the combined thicknesses of any two consecutive, adjacent documents  17 D (i.e., documents going to the same sort pocket) is equal to or less than the predetermined thickness, the first document  17 D 1  is diverted into by-pass transport  12 T by gate  31  and is temporarily held at that point. 
     When the following document  17 D 2  (which is going to the same pocket as document  17 D 1 ) approaches the exit of bypass transport  12 T, document  17 D 1  is fed (i.e., piggy-backed) onto document  17 D 2 . The two stacked documents will now travel along transport  12  as if a single document until it reaches its designated pocket 2nd is sorted accordingly. It should be appreciated that the unit  13  could easily be adapted to piggy-back multiple documents together, i.e., three or more documents traveling to the same designated pocket. 
     Referring now to  FIGS. 6 and 7  in the drawings, respective top and side views of an alternative embodiment of sorting machine  10  is shown. Sorting machine  601  is substantially similar in function to sorting machine  10 . In particular, sorting machine  601  is utilized to sort documents in a plurality of sorting pockets. Sorting machine  601  comprises one or more of the various systems discussed above, i.e., a feeder section, transport, level distribution unit, stacker section, and other required systems, to effectively and rapidly sort documents. It will be appreciated that sorting machine  601  could include one or more of the features of sorting machine  10 , and likewise, sorting machine  10  could easily be adapted with the features of sorting machine  601 . 
     Sorting machine  601  includes a first magazine  603  and a second magazine  605 , both magazines being located at the same end section  607  of sorting machine  601 , and both magazines being substantially similar in form and function to magazine  16 , discussed above. Magazine  603  and magazine  605  include a conveyor  609  for feeding documents onto a pickoff (not shown), which in turn, picks off one document at a time and delivers the document to a transport. In the preferred embodiment, a first transport  611  is operably associated with magazine  603  and a second transport  613  is operably associated with magazine  605 . During operation, a worker places documents  615  on magazine  603  and documents  617  on magazine  605 , which in turn are fed to and subsequently carried by respective transport  611  and transport  613 . For clarity, movement of both transport  611  and transport  613  are depicted with arrows on sorting machine  601 . The selectively positioning of both magazine  603  and magazine  605  at the same end section  607  allows a single worker to feed both transports simultaneously, thus reducing costs associated with employing multiple workers to perform the same job. 
     Sorting machine  601  preferably includes an elevator  621  utilized to elevate transport  611  at a height above a first level distribution unit  623  such that uninterrupted travel of documents  615  is achieved between feeder section  619  and a second level distribution unit  625 . During operation, documents  615  from magazine  603  are fed through feeder section  619  and are carried by transport  611  above first level distribution unit  623  via elevator  621  to second level distribution unit  625 . Thereafter, documents  615  are placed in the stream of partially sorted documents  617  from magazine  605 . This feature greatly increases sorting efficiency, as is further discussed below. 
     Like sorting machine  10 , sorting machine  601  comprises a stacker section  627  comprising a first section  629  having a plurality of pockets  631  and a second section  633  having a plurality of pockets  631 . In the preferred embodiment, stacker section  627  comprises two or more tiers  635 , preferably four tiers, to increase sorting capacity. However, it will be appreciated that alternative embodiments could include more or less tiers than the preferred embodiment. 
     It should be understood that a designated pocket for some of documents  617  could be positioned on section  629 , thus requiring documents  617  to travel the entire length of section  629  then reverse direction at a first buffer unit  637  prior to documents  617  traveling along section  629  to the designated pocket. Sorting machine  601  further comprises a second buffer unit  639  utilized to maintain continuous travel of both documents  615  and documents  617  around section  629  and section  633 , thus forming a continuous “loop” around stacker  627 . As documents  617  travel around first buffer unit  637 , documents  615  from magazine  605  are added thereto via transport  611 . This feature increases the efficiency of sorting machine  601  by placing documents  615  in a stream of documents  617  already sorted in section  633 . It should be understood that the remaining unsorted documents  617  have designated pockets located on section  629  of stacker  627 , thereby requiring the unsorted documents to travel the entire length of section  633  and reverse direction at first buffer unit  637 . Sorting documents  617  prior to merging documents  615  creates additional openings on transport  613  for receiving documents  615 , which in turn increases the sorting capacity of the documents and overall efficiency of sorting machine  601 . 
     Referring to  FIGS. 8 and 9  in the drawings, side views of sorting machine  601  are shown with a purge system  801 . Purge system  801  is utilized to remove documents  615  and documents  617  from their respective transports in one or more scenarios, including, but not limited to, the documents risk colliding with one another, the documents have an unknown pocket designation, and/or a jam occurs, which requires the tier to shut down for repair. Purge system  801  comprises one or more of a purge pocket  803  for storing the documents removed from the transport and an associated control system  805 , i.e., a sorter/supervisor board adapted to direct documents to pocket  803  during one or more of the foregoing scenarios. 
     Purge pocket  803  is preferably operably associated with turn around buffer unit  639 ; wherein, as one or the foregoing purge scenarios described above occurs, control system  805  activates a diverter means  1001  (see  FIG. 10 ), i.e., a gate, which in turn diverts documents  615  and documents  617  from transport  613  to pocket  803  for storing. After the jammed tier is fixed, control system  805  deactivates diverter means  1001  and the documents continue to their designated pocket. Thereafter, a worker collects the documents from pocket  803  and returns the unsorted documents to the magazine for resorting. In the preferred embodiment, pocket  803  is positioned next to turn around buffer unit  639 . However, it will be appreciated that alternative embodiments could include one or more purge pockets  803  selectively positioned at various locations on sorting machine  601 . For example, a purge pocket  803  could be position alongside pockets  631  of stacker  627  and/or one or more pockets  631  could be reserved as purge pockets. 
     Control system  805  is operably associated with a plurality of sensors  807  utilized to determine whether a jam  901  on the tier has occurred. If a jam does occur, control system  805  shuts down all sorting on the jammed tier and is adapted to activate controls, lever, motors, buffers, diverters, and other associated equipment utilized to direct the documents to purge pocket  803 .  FIG. 9  provides illustration of a jammed tier  635 , which is shut down and the documents diverted to purge pocket  803 . It will be appreciated that while the jammed tier is shut down, the other remaining 7 tiers (4 tiers on section  629  and 3 tiers on section  633 ) remain operable. 
     Purge system  801  greatly increases sorting efficiency of sorting machine  601 , in particular, purge system  801  enables sorting machine  601  to shut down a single tier in lieu of shutting down all tiers, thus allowing sorting machine  601  to remain operable. In the preferred embodiment, a single tier is shut down; however, it should be appreciated that alternative embodiments could include a purge system adapted to shut down one or more jammed pockets on a tier in lieu of shutting down the entire tier. This alternative embodiment enables the remaining pockets on the tier to operate while the jammed pocket(s) are undergoing maintenance. Furthermore, the preferred embodiment includes a purge pocket for each tier; however, it should be appreciated that alternative embodiments could include a single purge pocket adapted to store documents for all tiers and/or a designated tier utilized as a purge pocket. For example, section  633  could include a fifth tier having a plurality of pockets and being utilized as designated purge tier in lieu of a single purge pocket  803 . 
     Referring now to  FIG. 10A  in the drawing, a top view of buffer unit  639  and purge system  801  are shown. Buffer unit  639  includes a pulley  1003  utilized to turn around transport  613  such that continuous travel of transport  613  is achieved between buffer unit  637  and a pulley (not shown) of buffer unit  639 . Buffer unit  639  is further optionally provided with a first buffer  1005  and a second buffer  1007 , both buffers being utilized to prevent documents on the transport from colliding with each other. In the preferred embodiment, both buffer  1005  and buffer  1007  utilize one or more servomotors adapted to hold the documents in position. However, it should be appreciated that alternative embodiments could include solenoids and/or other suitable stopping means, i.e., suction devices, in lieu of the preferred embodiment. Solenoids are particularly desirable because they reduce the amount of starting and stopping of the transport belt. Also, it should be appreciated that alternative embodiments could include a buffer unit adapted to provide controlled collision of the documents. 
     During operation, one or more sensors (not shown) along transport  613  determines whether a document  1009  is likely to arrive at a merge point  1011  at the same time as an entering document  1013 . If the possibility of collision is imminent, document  1009  will be held in position with buffer  1005  until document  1013  passes merge point  1011 , at which time, document  1009  is released to resume travel to the designated sorting pocket  631 . Likewise, second buffer  1007  is utilized in a similar manner, namely, one or more sensors determine whether collision of a document  1015  is imminent with document  1009 , and if so, buffer  1007  holds document  1015  in position until document  1009  is released. The dual buffer configuration reduces collision between two or more documents on the transport, which increases the overall efficiency of the sorting operation. It should be appreciated that additional buffers could be utilized in alternative embodiments. For example, a buffer could be selectively position between first buffer  1005  and second buffer  1007 , thereby allowing an additional document to be held in position if collision is imminent. 
     Referring now to  FIG. 10B  in the drawing, a top view of an alternative embodiment of buffer unit  639  is shown operably associated with purge system  801 . Buffer unit  1000  is substantially similar in form and function to buffer unit  639  with additional significant features, as will be discussed below. Like unit  639 , buffer unit  1000  is also configured to retain one or more documents in a holding position when collision between documents is eminent. In the exemplary embodiment, buffer unit  1000  comprises a single buffer  1002  positioned upstream of a merge point  1004  and purge pocket  803  to prevent collision between entering documents and documents already traveling on transport  613 . It should be appreciated that the features of buffer unit  639  could be incorporated in buffer unit  1000 , and likewise the features of buffer unit  1000  could easily be used in one or more of the buffer units discussed herein. 
     Buffer unit  1000  further comprises a pulley  1006  adapted to rotatably turn directional movement of the document traveling along transport  613 . In the preferred embodiment, buffer  1002  utilizes one or more servomotors as means for retaining the documents in a holding position. However, it should be appreciated that alternative embodiments could include solenoids, suction devices, and/or other suitable stopping means in lieu of the preferred embodiment. Solenoids are particularly desirable because the solenoids are configured to reduce the amount of starting and stopping of the transport belt. 
     During operation, one or more sensors (not shown) operably associated with transport  613  senses whether a document  1008  traveling on transport  613  is likely to arrive at a merge point  1004  at the same time as an entering document  1010 . If the possibility of collision is imminent, document  1010  will be held in position with buffer  1002  until document  1008  passes merge point  1004 , at which time, document  1010  is released to resume travel to the designated sorting pocket  631 . 
     It will be appreciated that buffer unit  1000  can be operably associated with purge pocket  803 . For example, if a third document  1012  enters transport  613  while document  1010  is being retained in a holding position, diverter means  1001  is activated and the buffer releases document  1010 , which in turn is purged into purge pocket  803  via diverter means  1001 . This feature allows continuous travel of document  1012 , and subsequent documents, on transport  613  without colliding with document  1010 . 
     The buffer configuration reduces collision between two or more documents on the transport, which increases the overall efficiency of the sorting operation. It should be appreciated that additional buffers could be utilized in alternative embodiments. For example, the buffers of buffer unit  639  along with a buffer selectively position between first buffer  1005  and second buffer  1007  could be utilized with buffer  1002 , thereby allowing multiple documents being retained in a holding position for preventing collision. 
     Referring next to  FIG. 11  in the drawings, a flow chart  1101  illustrating the preferred method of sorting documents is shown. Box  1103  depicts the first step, which includes separating the documents into a first portion and a second portion. Thereafter, the first portion is carried to a first end of a tier of pocket and subsequently sorted, as depicted in boxes  1105  and  1107 . The second portion is simultaneously carried to a second end of the tier of pockets and then merged into the stream of already partially sorted documents from the first portion, as depicted in boxes  1109  and  1111 . The preferred embodiment also includes the process of removing the documents from the first transport with a purge system, as described above, and as depicted in box  1113 . Also, the preferred embodiment includes the process of stacking the document on one another with a stacking unit, as described above, and as depicted in box  1115 . 
     Referring now to  FIGS. 12 and 13  in the drawings, oblique view of a tray system  1201  is shown. Tray system  1201  is utilized to store documents that are removed from stacker section  627  as pockets  631  become full and/or during changing of schemes, as is further discussed below. In operation, a worker collects documents from the pockets and places the documents in a corresponding removable tray  1203  carried by tray system  1201 . Thereafter, the worker removes tray  1203  as tray  1203  becomes full and replaces tray  1203  with an empty tray. It should be understood that each tray  1203  carried by tray system  1201  corresponds to a pocket on stacker section  627 . For example, tray system  1201  could include twenty trays  1203 , each tray being designated to store documents from twenty different pockets of stacker section  627 . 
     Tray system  1201  preferably comprises a framed structure  1205  for supporting the plurality of trays  1203  and for supporting associated subsystems operably associated with tray system  1201 . In the preferred embodiment, tray system  1201  comprises eight rows  1207  for holding five trays  1203 ; however, alternative embodiments could include more or less rows  1207  and rows adapted to hold more or less trays than the preferred embodiment. Tray system  1201  includes four rows  1207  designated for a first scheme section  1209  and four rows  1207  designated for a second scheme section  1211 . It should be understood that sorting machine  601  could easily be adapted to operate with multiple schemes. Schemes are defined as operating scenarios, in particular, a first scheme occurs when sorting machine  601  sorts international documents, and a second scheme occurs when the documents are nationally sorted. For example, a first collection of documents could include designations to a plurality of countries, thereby designating a pocket  631  to individual countries; whereas, in the second scheme, each pocket could be designated for each state within the United States. Of course, it should be understood that these two exemplary schemes are one example of many different types of schemes operably associated with sorting machine  601 . It should be appreciated that alternative embodiments could include more or less schemes than the preferred embodiment. Providing a tray system with multiple scheme sections greatly increases the overall efficiency of tray system  1201 , namely, the worker is no longer required to remove trays from the tray system as the sorting machine switches between schemes. 
     Tray system  1201  further comprises a lift subsystem  1213  operably associated with a drive system  1215 . Lift subsystem  1213  is utilized to lower and raise rows  1207  relative to the floor. For example,  FIG. 12  shows rows  1207  at a lower position, while  FIG. 13  shows rows  1207  at an elevated position. During operation, a worker manipulates a switch  1217 , which in turn activates drive subsystem  1215  and lift subsystem  1213 . Switch  1217  can subsequently be manipulated by the worker to lower rows  1207  to the lower position. This feature of raising and lowering the rows provides ergonomic advantageous, specifically, a worker is no longer required to bend over to reach and stack documents near the floor. In the preferred embodiment, the worker simply manipulates switch  1217  to elevate the bottom rows for stacking. 
     Lift subsystem  1213  preferably comprises one or more of a chain  1219  rotatably coupled to a top gear  1221  and a bottom gear  1223 . Rows  1207  are securely held in position with a rigid sidewall  1225 , which includes one or more brackets  1227  adapted to fasten to chain  1219 . Drive subsystem  1215  preferably includes a motor  1229  rotatably coupled to a drive shaft  1231 , which in turn is rotatably coupled to gear  1221 . During operation, drive subsystem  1215  rotates gear  1221 , which in turn causes rows  1207  to raise or lower via movement of chain  1219 . Of course, it will be appreciated that alternative embodiments could include different means for lifting the rows. For example, the tray system could easily be adapted with a worm gear system, a hydraulic system, gear system, and/or other suitable systems adapted to lower and raise an object. 
     Referring next to  FIGS. 14 and 15 , respective oblique and top views of an alternative embodiment of magazine  603  are shown. Magazine  1401  is substantially similar in form and function to magazine  603  and could include all the features of found therein, and likewise, the features of magazine  1401  could easily be incorporated in one or more of the magazines discussed above. Like magazine  603 , magazine  1401  provides means for feeding documents to the stacker section. It will be appreciated that magazine  1401  provides significant advantages over other magazine embodiments. Specifically, magazine  1401  feeds documents to both transport  611  and  613  simultaneously. For example, during operation a worker places the documents onto the two conveyors, each conveyor being operably associated with one of the two transports passing through the stacker section. This embodiment allows a single worker to perform a job generally designated for two workers, thus greatly reducing the cost of operation. 
     For ease of description, not all of the required subsystems and devices operably associated with magazine  1401  are shown. For example, the necessary sensors, connectors, power sources, mounting supports, circuitry, software, control systems, and so forth are not all shown in order to clearly depict the novel features of the magazine. However, it should be understood that the magazine is operably associated with these and other required systems and devices for operation, as conventionally known in the art, although not discussed and depicted in the drawings. 
     Magazine  1401  comprises one or more of a structure  1403  for supporting the various components and systems of magazine  1401  thereon. A first conveyor  1405  and a second conveyor  1407  are supported by structure  1403  and are configured to receive the unsorted documents. Structure  1403  is further optionally provided with a working area  1409  for placing the documents thereon prior to positioning the documents on the conveyors. 
     Conveyor  1405  includes a track  1411  operably associated with a slider  1413 , and likewise, conveyor  1407  includes a track  1415  operably associated with a slider  1417 . In the preferred embodiment, both track  1411  and track  1415  are oriented relatively parallel to each other to facilitate easily loading of the documents thereon. In addition, track  1411  is positioned at a height relative to track  1415  for further ease of use. In the preferred embodiment, magazine  1401  includes two tracks at a height relative to each other. However, it will be appreciated that alternative embodiments could include three or more tracks and having the same or a height elevation relative to each other. During operation, the tracks are configured to move the sliders in direction D 1 , which in turn push the documents to feeders  1419  and  1421 . It should be appreciated that feeders  1419  and  1421  are substantially similar in form and function to one or more of the feeders discussed above. Feeder  1419  is configured to feed the documents to transport  611 , while feeder  1421  is configured to feed the documents to transport  613 . 
     It should be appreciated that the sliders are either operated in a locked position or an unlocked position. In particular, during operation a worker slidingly moves the slider along the conveyor in an unlocked position to place the documents on the conveyor. Thereafter, the worker slides the slider along the track to abut the slider against the documents, and then locks the slider to the moveable track with a locking mechanism (not shown). The worker repeats this process as additional documents are placed on the conveyors. 
     Magazine  1401  is further provided with a control system  1423  for controlling the various systems and devices associated with sorting machine  601 . In the preferred embodiment, control system  1423  includes a control panel  1425  conductively coupled to a monitor  1427 . During operation, a worker manipulates control panel  1425  for activating/deactivating the various systems of sorting machine  601 , while monitor  1427  provides viewing access to the operation of the systems associated with sorting machine  601 . 
     It is apparent that a sorting machine with significant advantages has been described and illustrated. In particular, the sorting machine effectively and rapidly sorts documents by providing two transports, the first transport utilized to carry documents through a plurality of sorting bins and a second transport utilized to merge documents into the stream of documents already partially sorted with the first transport. This features enables both a first magazine operably associated with the first transport and a second magazine operably associated with the second transport to be position at the same end section of the sorting machine, thus enable a single worker to feed both magazines simultaneously, which in turn allows a single worker to feed documents into the sorting machine in lieu of multiple workers performing the same job. In addition, the sorting machine is adapted with a purge system, which allows documents to be removed from the machine, thus enabling the sorting machine to continue operation while the jammed tier is being repaired. Further, the sorting machine could include a magazine configured to feed both transports simultaneously. 
     The particular embodiments disclosed above are illustrative only, as the embodiments may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the description. Although the present embodiments are shown above, they are not limited to just these embodiments, but are amenable to various changes and modifications without departing from the spirit thereof.