Patent Publication Number: US-6217274-B1

Title: Continuous flow transfer system

Description:
FIELD OF THE INVENTION 
     The present invention relates to mail handling equipment for rapidly processing mail, and in particular to an automated continuous flow transfer system for transferring the mail pieces contained within plastic or cardboard mail trays into cartridges for processing and then transferring the processed mail pieces contained within the cartridges back into mail trays for subsequent delivery. 
     BACKGROUND OF THE INVENTION 
     Although the present invention may be used in connection with other applications, the present invention was designed for automated mail handling. Currently, mail is typically transported in flexible plastic or cardboard trays. As such, these trays do not always interface well with certain processing operations, and in particular, fully automated processing operations. To have a fully automated processing operation, it has become desirable to develop a machine or system that automatically transfers the contents of the mail trays into sturdy cartridges of uniform size and weight specially designed for interfacing with a given processing operation. Then, once the mail is processed, the machine or system would transfer the contents of the cartridges back into the mail trays for transport to delivery points. The automated mail transfer system must also have the ability to maintain the facing, orientation and order of each mail piece throughout the transfer process as to not disturb the mail processing procedure. 
     Accordingly, the present invention provides a unique automated continuous transfer system that provides for the transfer of mail from a mail tray into a specially designed cartridge and then, after processing, for transferring the mail from the cartridges back into the mail trays or other mail containers, without disturbing the facing and orientation of each mail piece. 
     SUMMARY OF THE INVENTION 
     The primary object of the present invention is to provide an automated device for loading and unloading mail trays of various sizes into and out of cartridges specifically designed to interface with certain mail processing operations. 
     Another object of the present invention is to provide a transfer apparatus that maintains the mail facing and orientation throughout the transfer process. 
     Yet another object of the present invention is to provide a mail transfer apparatus that transfers mail pieces from a mail tray to a cartridge and back into a mail tray with minimal loss or damage to each mail piece. 
     Still another object of the present invention is to provide a mail transfer apparatus that provides for smooth exchange of content. 
     A further object of the present invention is to provide a mail transfer apparatus having the capability of dividing mail contained within a completely filled mail tray and placing that mail into two separate cartridges, if necessary for further processing. 
     In accordance with these and other objects, the present invention provides a continuous flow transfer system for transferring the contents of a mail tray into a cartridge for processing and then transferring the contents of the cartridge back into a mail tray, subsequent to processing of the mail without disrupting the order, facing or orientation of the contents of the mail. The continuous flow transfer system comprises both a cartridge loader and a cartridge unloader. Both the cartridge loader and the cartridge unloader are comprised of a tray section, a transfer conveyor and a cartridge section. 
     The tray section, or infeed section, of the cartridge loader is designed to deliver loaded mail trays to the transfer section of the loader where the contents of each mail tray are then deposited into an intermediate container that is affixed to the transfer section The transfer section then delivers the contents of the intermediate container into empty cartridges being supplied by the cartridge section. Once filled, each cartridge then exits the cartridge section, or discharge section, of the cartridge loader. The cartridges are transported to an intermediary processing operation where the mail is removed from the cartridges for processing. Once processed, the mail is re-deposited into cartridges, and each cartridge is then delivered to the cartridge unloader by the cartridge section, or input section, of the cartridge unloader. The contents of each cartridge are then transferred into an intermediate container that is affixed to the transfer section of the cartridge unloader. The transfer section then delivers the contents of the intermediate container back into mail trays for further transport and delivery. Once in the mail trays, the filled mails trays then exit the tray section, or discharge section, of the cartridge unloader. The filled mail trays are then transported to an area for subsequent delivery. 
     As seen in the attached figures, the transfer section of both the loader and unloader is interposed between the tray section and cartridge section to maintain the order, facing and orientation of the mail pieces within the trays and cartridges. In the case of the loader, the transfer section may be designed to divide the contents of a mail tray for deposit into two cartridges, when necessary. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of one embodiment of the cartridge loader of the present invention utilizing a powered flat belt conveyor system. 
     FIG. 2 is a side view of another embodiment of the cartridge loader of the present invention utilizing a powered chain conveyor system. 
     FIG. 3 is a front perspective view of one embodiment of the cartridge unloader of the present invention utilizing a powered flat belt conveyor system. 
     FIG. 4 is a side view of another embodiment of the cartridge unloader of the present invention utilizing a powered chain conveyor system. 
     FIG. 5 is a perspective view of the framework or support structure of the cartridge loader and unloader of the present invention utilizing a powered chain conveyor system. 
     FIG. 6 is the opposing side view of the framework or support structure of the cartridge loader and unloader illustrated in FIG.  5 . 
     FIG. 7 is a side perspective view of the cartridge loader and unloader illustrated in FIG.  5 . 
     FIG. 8 is a front perspective view of the tray transport section of the cartridge loader illustrated in FIG.  1 . 
     FIG. 9 is a side view of the tray transport section of the cartridge loader illustrated in FIG.  2 . 
     FIG. 10 is the side perspective view of a single frame of the cartridge or tray section of the cartridge loader and unloader illustrated in FIG.  5 . 
     FIG. 11 is a plan perspective view of an engaging carriage of the present invention designed for use with a cartridge loader or cartridge unloader having only one engaging mechanism. 
     FIG. 12 is a bottom perspective view of the engaging carriage having two engaging mechanisms. 
     FIG. 13 is a front view of the engaging mechanism of the engaging carriage illustrated in FIGS. 11 and 12 shown in its disengaged position. 
     FIG. 14 is a front view of the engaging mechanism of the engaging carriage illustrated in FIGS. 11 and 12 shown in its engaged position. 
     FIG. 15 is a side view of an engaging carriage of the present invention designed for use with a cartridge loader utilizing the powered chain conveyor system illustrated in FIGS. 2 and 4. 
     FIG. 16 is a front view of the engaging carriage illustrated in FIG.  15 . 
     FIG. 17 is a plan detail view illustrating the mounting of the engaging carriage illustrated in FIG. 15 to a powered chain conveyor system. 
     FIG. 18 is a side view illustrating the interfacing of the engaging carriages illustrated in FIG. 15 and a cam guide located on the frame sections of the present invention. 
     FIG. 19 is a perspective view of the chain track of the loader and unloader transfer conveyor of the cartridge loader and cartridge unloader illustrated in FIG.  5 . 
     FIG. 20 is a front perspective view of the loader and unloader transfer conveyor of the present invention utilizing a powered flat belt conveyors system and having non-divisible intermediate containers. 
     FIG. 21 is a front view of the loader transfer conveyor of the present invention utilizing a powered chain conveyor system. 
     FIG. 22 is a plan view of the unloader transfer conveyor illustrated in FIG.  21 . 
     FIG. 23 is an enlarged plan view of the intermediate container illustrated in FIG.  21 . 
     FIG. 24 is a front perspective view of the intermediate container of the present invention designed to divide a single mail stack into two separate parts. 
     FIG. 25 is a rear perspective view of the intermediate container illustrated in FIG.  24 . 
     FIG. 26 is a bottom perspective view of the intermediate container illustrated in FIG.  24 . 
     FIG. 27 is a bottom perspective view of the front half of the intermediate container illustrated in FIG.  26 . 
     FIG. 28 is a bottom perspective view of the rear half of the intermediate container illustrated in FIG.  26 . 
     FIG. 29 is a side elevation view of the intermediate container illustrated in FIG.  23 . 
     FIG. 30 is a sectional view of the intermediate container illustrated in FIG. 23 shown while in process of actuating taken along line  30 — 30 . 
     FIG. 31 is a side elevation view of the intermediate container illustrating the compressing system of the present invention. 
     FIG. 32 is a front view of a shaft hanger of the mail compressing system of the present invention. 
     FIG. 33 is a rear view of the intermediate container illustrated in FIG.  29 . 
     FIG. 34 is a rear view of the paddle and shaft housing of the mail compressing system of the present invention. 
     FIG. 35 is a plan view of the base of the intermediate container of the present invention. 
     FIG. 36 is a side view of the base of the intermediate container illustrated in FIG.  35 . 
     FIG. 37 is a bottom view of the mail dividing mechanism of the present invention. 
     FIG. 38 is a plan view of the finger plate assembly of the mail dividing mechanism as illustrated in FIG.  37 . 
     FIG. 39 is a side view of the mail dividing mechanism illustrated in FIG.  37 . 
     FIG. 40 is a front view of the mail dividing mechanism illustrated in FIG.  39 . 
     FIG. 41 is a sectional view of the mail dividing mechanism illustrated in FIG. 42 taken along line  41 — 41 . 
     FIG. 42 is a sectional view only of the mail dividing mechanism illustrated in FIG. 30 taken along line  42 — 42 . 
     FIG. 43 is a sectional view of the mail dividing mechanism illustrated in FIG. 37 taken along line  43 — 43 . 
     FIG. 44 is a front perspective view of the intermediate container illustrated in FIG. 24 as it would appear lifting a portion of a mail stack away from the other portion of the mail stack. 
     FIG. 45 is a front perspective view of the intermediate container illustrated in FIG. 24 as it would appear after it has divided the original mail stack into two separate stacks. 
     FIG. 46 is a rear perspective view of the intermediate container as illustrated in FIG. 45 taken along line  46 — 46 . 
     FIG. 47 is a plan view of a side wall and portion of the split front wall of the intermediate container illustrated in FIG.  23 . 
     FIG. 48 is a plan view of the pinion housing of the width adjustment mechanism of the intermediate container of the present invention. 
     FIG. 49 is a front view of the cross bar assembly of the width adjustment mechanism of the intermediate container of the present invention. 
     FIG. 50 is a side view of the pinion housing illustrated in FIG. 48 
     FIG. 51 is a front view of the pinion housing illustrated in FIG.  48 . 
     FIG. 52 is a front perspective view of the loader cartridge section of the present invention as illustrated in FIG.  1 . 
     FIG. 53 is a rear perspective view of the loader cartridge section illustrated in FIG.  52 . 
     FIG. 54 is a flow diagram of the operation of the automated continuous flow transfer system of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     As seen in FIGS. 1-4 and  54 , the present invention relates to an automated continuous flow transfer system  60  comprising a cartridge loader  62 , cartridge unloader  64  and an intermediary processing operation  63 . Referring to FIGS. 1 and 3, the automated continuous flow transfer system  60  provides for the uninterrupted transfer of mail pieces  66  initially contained in plastic or cardboard mail trays  68  into sturdy cartridges  70  of uniform size and weight, and then from the cartridges  70  back into the plastic or cardboard mail trays  68  once the mail pieces  66  in the cartridges  70  have been processed. A flow diagram of this automated continuous flow transfer system  60  is illustrated in FIG.  54 . 
     As seen in FIGS. 1-4, the cartridge loader  62  and cartridge unloader  64  may be comprised of either (1) an interfacing powered flat belt conveyor system  72 , as illustrated in FIGS. 1 and 3, (2) a powered chain conveyor system  74 , as illustrated in FIGS. 2 and 4, or (3) other like conveyor systems designed to transfer mail trays  68  and cartridges  70  in a 360 degree (360°) rotation. 
     The cartridge loader  62  of the present invention provides for the transfer of the mail pieces  66  contained in the mail trays  68  into sturdy cartridges  70  of a standard size and weight specially designed to interface with an intermediary processing operation  63  (FIG.  54 ). Once deposited in the cartridges  70  by the cartridge loader  62 , the mail pieces  66  are then delivered to the intermediary processing operation  63 . After processing, the mail pieces  66  are then transferred back into the mail trays  68  by the cartridge unloader  64  for transport of the processed mail  66  to its next destination and ultimate delivery to the addressee. 
     In operation, the cartridge loader  62 , with the few exceptions, operates similar to the cartridge unloader  64 , except that the cartridge unloader  64  operates in the opposite direction of the cartridge loader  62 . Therefore, the same underlying conveyor structure can be utilized for both the cartridge loader  62  and cartridge unloader  64 . For example, the powered chain conveyor system  74  depicted in FIGS. 5,  6  and  7  could be used as either a cartridge loader  62  or a cartridge unloader  64 , depending upon the direction of movement of the conveyor system  74 . Thus, for those figures intended to specifically depict a cartridge loader  62  or a cartridge unloader  64 , directional arrows have been provided on the drawings to aid in the understanding of the present invention and to aid in the recognition of the specific conveyor systems. 
     Two embodiments of the cartridge loader  62  of the present invention are illustrated in FIGS. 1 and 2. FIG. 1 illustrates the powered flat belt conveyor design  72  and FIG. 2 illustrates the powered chain conveyor design  74 . Two embodiments of the cartridge unloader  64  of the present invention are illustrated in FIGS. 3 and 4. FIG. 3 illustrates the powered flat belt conveyor design  72  and FIG. 4 illustrates the powered chain conveyor design  74 . A detailed description of both the cartridge loader  62  and cartridge unloader  64 , including all component parts, is found below. 
     A. Cartridge Loader  62   
     As seen in FIGS. 1 and 2, the cartridge loader  62  comprises of a loader tray section  76 , a loader transfer conveyor  78 , and a loader cartridge section  80 . As further seen in FIGS. 1 and 2, the loader tray section  76 , loader transfer conveyor  78  and loader cartridge section  80  are all interfaced with one another to provide for the uninterrupted transport of mail pieces  66  from the mail trays  68  into cartridges  70 . 
     As illustrated in FIGS. 1 and 2, the loader tray section  76  receives full mail trays  68  from a tray management system (TMS), transports the mail trays  68  in synchronization with the loader transfer conveyor  78  to unload the mail  66  from the trays  68  into intermediate containers  82  located on the loader transfer conveyor  78  and then transfers the empty trays  68  back to the TMS. 
     The loader transfer conveyor  78  is located in the central portion of the cartridge loader  62  illustrated in FIGS. 1 and 2, and is comprised of evenly spaced intermediate containers  82  that accept the mail  66  from the filled mail trays  68  on the loader tray section  76 . The loader transfer conveyor  78  then transports the mail pieces  66  in the intermediate containers  82  to the point where the loader transfer conveyor  78  interfaces with the loader cartridge section  80 . At that point, the mail pieces  66  are then transferred from the intermediate containers  82  into empty cartridges  70  located on the loader cartridge section  80 . 
     The loader cartridge section  80  is located in the left of FIGS. 1 and 2 and functions to receive empty cartridges  70  from the TMS, transport the cartridges  70  in synchronization with the intermediate containers  82  on the loader transfer conveyor  78  while mail  66  is loaded from the intermediate containers  82  of the loader transfer conveyor  78  into the cartridges  70 , and then transfer the loaded cartridges  70  to the intermediary processing operation  63  (FIG.  54 ). 
     Although FIGS. 1 and 2 show the loader cartridge section  80  designed to interface two empty cartridges  70  at one time with a single intermediate container  82  on the loader transfer conveyor  78 , the loader cartridge section  80 , when required, can interface only one cartridge  70  at a time with an intermediate container  82  on the loader transfer conveyor  78 . The loader cartridge section  80 , therefore, is designed to communicate with the loader transfer conveyor  78  and feed either one cartridge  70  or two cartridges  70  at any one time toward the loader transfer conveyor  78  as necessary to accommodate the amount of mail  66  contained in the interfacing intermediate container  82 . 
     To better understand the functionality of the cartridge loader  62  of the present invention, a detailed summary of each section of the cartridge loader  62  follows. The basic principles of construction and operation of the cartridge loader  62  of FIGS. 1 and 2 are substantially the same, unless otherwise noted. 
     1. Loader Tray Section  76   
     As shown in FIG. 8, the loader tray section  76  can be divided into three component parts: (1) a tray input conveyor  84 , (2) a tray transport conveyor  86  and (3) a tray output conveyor  88 . Although FIG. 8 illustrates the loader tray section  76  as it would appear on a powered flat belt conveyor design  72  of FIG. 1, the same three components are present in the powered chain conveyor design  74  of FIG.  2 . As will be further described below, the only differences in the two conveyor designs  72  and  74  with regard to the loader tray section  76  is the manner in which the mechanism that secures the mail trays  68  to the conveyor system  72  or  74  is affixed to the loader tray section  76 . 
     As best illustrated by FIGS. 1 and 8, the tray input conveyor  84  of the loader tray section  76  receives trays  68  loaded with mail  66  from the TMS and feeds the supply of trays  68  to the tray transport conveyor  86 . The tray transport conveyor  86  accepts the loaded trays  68  from the tray input conveyor  84 , releasably secures the trays  68  to the conveyor  72  (FIG. 1) or  74  (FIG. 2) and transfers the mail  66  in the mail trays  68  to the intermediate containers  82  located on the loader transfer conveyor  78 , as will be described. Once the trays  68  are empty, the tray transport conveyor  86  then passes the empty trays  68  to the tray output conveyor  88 , releases the empty trays  68  from conveyor  72  or  74 , and the tray output conveyor  88 , then transports the empty mail trays  68  back to the TMS. A detailed summary of each of the three component parts of loader tray section  76  follows. 
     a. Tray Input Conveyor  84   
     Loaded trays  68  are supplied to the tray input conveyor  84  from the TMS and are delivered to the tray transport conveyor  86  by a powered roller conveyor  90  having pusher fingers  94  that engage the loaded trays  68 . The powered roller conveyor  90  interfaces with the TMS to receive loaded trays  68  and then, as illustrated in FIG. 8, transports trays  68  to the area adjacent to the tray transport conveyor  86 . The powered roller conveyor  90  advances the trays  68  into the cartridge loader  62  such that the end  92  of the trays  68  is brought first into the cartridge loader  62 . Furthermore, the trays  68  are advanced into the cartridge loader  62  so that the trays  68  are registered to align with the intermediate containers  82  of the loader transfer conveyor  78  when advanced toward the tray transport conveyor  86 , as will be explained. 
     At the properly synchronized time, the tray input conveyor  84  actuates a pusher finger  94  on a finger belt conveyor  96  that advances a tray  68  toward the tray transport conveyor  86  in synchronization with a pusher paddle  98  located on the tray transport conveyor  86 . As described in more detail below, the pusher paddle  98  of the tray transport conveyor  86  is part of an engaging mechanism  100  (FIG. 11) that engages and maintains each loaded mail tray  68  against the tray transport conveyor  86  until the mail tray  68  reaches the tray output conveyor  88 , where it is then released from the tray transport conveyor  86  and returned to the TMS by the tray output conveyor  88 . 
     b. Tray Transport Conveyor  86   
     As seen in FIGS. 8 and 9, the tray transport conveyor  86  generally comprises of a series of engaging carriages  102  located at fixed pitch points, in the illustrated embodiments. As further seen in FIGS. 2 and 9, in one embodiment of the present invention, the tray transport conveyor  86  is designed as a part of a powered chain conveyor system  74 . In this embodiment, the tray transport conveyor  86  is comprised of a supporting structure  104  and two opposing frame members  106  mounted to the supporting structure  104  such that the frame members  106  are aligned with one another and elevated off the ground to allow the engaging carriages  102  to pass underneath the frame members  106 . Although not shown in the attached figures, similar frame members with a supporting structure would be used in the embodiment utilizing a powered flat belt conveyor design. 
     As seen in FIGS. 6,  7  and  10 , each frame member  106  has a track  108  for housing a conveyor chain  110 . Each conveyor chain  110  is driven by a motor  112  connected to a shaft  114  that drives toothed sprockets  116  mounted on the frame members  106 . The toothed sprockets  116  then engage the conveyor chain  110  and, as the toothed sprockets  116  rotate, move the conveyor chain  110  through the track housing  108  on the frame members  106 . Since the conveyor chains  110  on the tray transport conveyor  86  are aligned with one another, the same motor  112  and shaft  114  may be used to turn the toothed sprockets  116  mounted on each opposing frame member  106 , as illustrated in FIG.  6 . 
     When used with a powered chain conveyor system as illustrated in FIG. 2, the engaging carriages  102  of the tray transport conveyor  86  are pivotally mounted at each end to the conveyor chains  110  such that the engaging carriages  102  span between and are held at their ends by the conveyor chain  110  moving through each frame member  106 . To engage the ends of the engaging carriages  102 , each conveyor chain  110  has L-shaped mounting brackets  118  integral to and extending from the conveyor chain  110  at fixed pitch points as illustrated by FIGS. 17,  18  and  19 . These L-shaped mounting brackets  118  have one end of the bracket  118  integral to a chain link on the conveyor chain  110 , while the other end of the mounting bracket  118  extends upward and away from the conveyor chain  110  to allow for the attachment of engaging carriages  102  to the opposing end of the mounting bracket  118 . 
     While the ends of the engaging carriages  102  may be rigidly mounted to the mounting brackets  118 , the engaging carriages  102  of the present invention, when used in connection with the powered chain conveyor system  74 , are pivotally connected to the conveyor chain  110 . As seen in FIGS. 9,  17  and  18 , this pivotal connection is accomplished by mounting shafts  120  to the lateral exposed ends of the mounting brackets  118  and then interfacing the shafts  120  with arm gussets  122  located at each end of the engaging carriages  102  (FIG.  18 ). 
     By pivotally connecting the engaging carriages  102  to the conveyor chains  110  of the tray transport conveyor  86 , a more condensed and modular cartridge loader  62  can be designed. Because the engaging carriages are pivotally connected to the conveyor chains  110 , the force of gravity will cause the engaging carriages  102 , especially when gripping a mail tray  68 , to be completely inverted and face downward when traveling along the tray transport conveyor  86 . Thus, the tray transport conveyor  86  does not need as steep an angle of incline or decline on the frame tracks  108  to invert the trays  68 . The trays  68  are inverted naturally by the effect of gravity. However, because of this natural tendency to hang in the inverted position, a separate mechanism must be utilized to maintain the engaging carriages  102  in a position not otherwise dictated by gravity. 
     Referring to FIG. 18, to maintain the engaging carriages  102  in a desired position not dictated by gravity, the engaging carriages  102  are designed to interface with the frame member  106  through cam follower  124  and a cam guide  126 . In this embodiment, the engaging carriages  102  of the tray transport conveyor  86  are designed to include cam followers  124  located at each end of the engaging carriages  102 . Each frame member  106  is then designed to have a corresponding cam guide  126  located on the frame member  106  that engages the cam follower  124  on the engaging carriages  102  when it is desirable to maintain the carriages  102  in a given position. For example, it is desirable to have the carriages  102  in an upright and parallel position with the movement of the conveyor chains  110  when the engaging carriages  102  are advanced to engage a mail tray  68  as shown at the bottom left portion of FIG.  9 . 
     Rather than mounting the ends of the engaging carriages  102  directly to a conveyor chain  110 , the tray transport conveyor  86  can be designed, as seen in FIG. 8, to include a powered flat belt conveyor  72  having the engaging carriages  102  located at fixed pitch points along the belt. In this embodiment, the engaging carriages  102  would not pivot, but be rigidly affixed to the belt. In general, the design of the engaging carriages  102  are the same whether affixed to a belt conveyor or whether mounted directly to a conveyor chain  110 . As discussed above, the main difference between the engaging carriages  102  is the manner in which the carriages  102  are mounted to the conveyor system  72  or  74 , which, as illustrated by the drawings, may also slightly effect the body design of the carriages  102 . FIGS. 11 and 12 illustrate an engaging carriage  102  designed for use in connection with a powered flat belt conveyor system  72 . FIGS. 15 and 16 illustrate an engaging carriage  102  designed for use in connection with a powered chain conveyor system  74 . 
     Although the body design of the engaging carriages  102  may vary slightly, the function and operation of the engaging carriages  102  in the present invention remains the same. Described below is a detailed description of the engaging carriages  102  as used in connection with either conveyor system  72  or  74 . 
     The engaging carriages  102  on the tray transport conveyor  86  are used to secure and transport the trays  68  from the tray input conveyor  84  to the tray output conveyor  88 , and to transfer the mail pieces  66  to intermediate container  82  (FIGS.  1  and  2 ). As seen in FIGS. 11 through 16, each engaging carriage  102  is comprised of an undercarriage base  128  that houses an engaging mechanism  100 . The engaging mechanism  100  is comprised of at least one pusher paddle  98  and at least one gripper paddle  130  that combine to secure each tray  68  against the engaging carriage  102 . As will become more apparent later in the disclosure, the engaging mechanism  100  of the tray transport conveyor  86  are utilized throughout the present invention in most all instances where a conveyor system  72  or  74  is required to engage and maintain a mail tray  68  or cartridge  70  for a set distance and at an inverted position for at least a portion of such distance. 
     As illustrated by FIGS. 11 and 12, each engaging carriage  102  can include one or more engaging mechanisms  100 . It is preferred that two engaging mechanisms  100  are used with each carriage  102 , as seen in FIGS. 12 and 15, so that each engaging carriage  102  can readily accommodate both large and small sized mail trays  68 . FIG. 11 illustrates an engaging carriage  102  having only one engaging mechanism  100 , while FIGS. 12 and 15 illustrate an engaging carriage  102  having two engaging mechanisms  100 . 
     The undercarriage base  128  is designed to have a raised tray support platform  132  that serves to support the trays  68  coming off the tray input conveyor  84 . As seen in FIGS. 11 through 15, the tray support platform  132  is lowered on each side of the engaging mechanism  100  to provide clearance areas  134  for the passage of the finger belt conveyors  96  that advance the trays  68  from the powered rolled conveyor  90  toward the tray transport conveyor  86 . 
     As seen in FIGS. 13 and 14, each engaging mechanism  100  is comprised of a pivotal pusher paddle  98 , a pivotal gripper paddle  130 , a paddle linkage rod  136 , a pair of springs  138  and a connecting bar  140 . FIG. 13 represents the engaging mechanism  100  in its relaxed state, wherein, the pusher paddle  98  is inclined slightly forward and the gripper paddle  130  is in a parallel plane with the connecting bar  140 . The paddles  98  and  130  which pivot about center at each end of the connecting bar  140  and are connected to one another by the paddle linkage rod  136 . A pair of springs  138  also extends between the gripper paddle  130  and the connecting bar  140  to add tension to the gripper paddle  130  when engaged to maintain a tray  68 . 
     Each engaging mechanism  100  will remain in its relaxed state until coming into contact with a mail tray  68 . When engaged with a mail tray  68 , the engaging mechanism  100  will appear as illustrated in FIG.  14 . Under the influence of the leading side edge of the advancing mail tray  68 , the pusher paddle  98  will be forced into its upright position by its contact with the side of tray  68 , the paddle linkage rod  136  will move to the right as shown in FIG. 13 by the arrow, and will push the gripper paddle  130  and rotate the gripper paddle  130  upward ninety degrees (90°), to engage the opposing or trailing side of the advancing mail tray  68 . The springs  138  are then extended to an over-center position when the gripper paddle  130  is positioned upward, creating tension on the gripper paddle  130  and causing a film grasp of the tray  68  between the pusher paddle  98  and gripper paddle  130 . 
     In operation, the movement of the trays  68  from the tray input conveyor  84  by the finger belt conveyor  96  (FIG. 8) is synchronized with the movement of the engaging carriages  102  on the tray transport conveyor  86  such that the trailing edge of a tray  68  arrives at the transfer point between tray transport conveyor  86  and finger belt conveyor  96  just before the pusher paddle  98  of an engaging carriage  102 . The pusher paddle  98  then makes contact with the side of the tray  68 . When the pusher paddle  98  comes in contact with the mail tray  68 , the weight of the tray  68  moves the pusher paddle  98  rearward and into its upright position, as shown in FIG.  14 . As the tray  68  is moved against the pusher paddle  98 , the spring loaded gripper paddle  130  rotates upward ninety degrees (90°) to grip the tray  68  firmly between the pusher paddle  98  and the gripper paddle  130 . The advancing engaging carriages  102  continue to firmly engage each mail tray  68  until the mail tray  68  reaches the tray output conveyor  88  (FIG. 8) at which point it is released and fed to the tray output conveyor  88  for subsequent transfer to the TMS. 
     As seen in FIG. 1, the transfer of the mail  66  from the mail trays  68  to the intermediate containers  82  is accomplished by not only aligning the engaging carriages  102  with the intermediate containers  82  but also matching the horizontal component of the velocities of the tray transport conveyor  86  and the loader transfer conveyor  88 . When an intermediate container  82  initially overlaps an engaging carriage  102 , supporting a mail tray  68 , the intermediate container  82  is inverted and the mail tray  68  is positioned upright. At this point, the intermediate container  82  has enveloped the top of the mail tray  68 . As the conveyors  86  and  78  advance at the same horizontal velocity, the mail tray  68  and intermediate container  82  are synchronously transported through a one-hundred eighty degree (180°) directional change through the vertical axis. This change of direction renders the mail tray  68  inverted and the intermediate container  82  in its upright position. During this directional change, all the mail  66  in the mail tray  68  is transferred by gravity to the intermediate container  82 . After the transfer of the mail  66  into the intermediate container  82 , the now empty trays  68  are conveyed by the tray transport conveyor  86  to the tray output conveyor  88  (FIG.  8 ). 
     c. Tray Output Conveyor  88   
     As seen in FIG. 8, the tray output conveyor  88 , like the tray input conveyor  84 , consists of a powered roller conveyor  90  that receives the empty trays  68  from the tray transport conveyor  86 . Before transfer to the tray output conveyor  88 , the gripper paddle  130  of the engaging mechanism  100  on the tray transport conveyor  86  is released and pivoted downward so that transfer of the tray  68  to the tray output conveyor  88  can be accomplished. A pusher finger  94  on finger belt conveyor  96  may be used to move the empty trays  68  off of the tray transport conveyor  86  and onto the tray output conveyor  88 , similar to the manner in which the loaded trays  68  were transferred from the tray input conveyor  84  to the tray transport conveyor  86 . Once received by the tray output conveyor  88 , the empty trays  68  are then conveyed to the TMS to receive additional mail and repeat the cycle of operation. 
     2. Loader Transfer Conveyor  78   
     As illustrated by FIGS. 1 and 2, the loader transfer conveyor  78  of the present invention provides for the intermediary handling of the mail pieces  66  being transferred into either one or two mail cartridges  70 . As seen in FIGS. 20,  21  and  22 , the loader transfer conveyor  78 , like the tray transport conveyor  86 , generally consists of a series of intermediate containers  82  affixed to the conveyor system  72  or  74  at fixed pitch points. FIGS. 1 and 20 illustrate the loader transfer conveyor  78  designed for use with a powered flat belt conveyor system  72 . FIGS. 2,  21  and  22  illustrate the loader transfer conveyor  78  as it would appear as part of a powered chain conveyor system  74 . 
     In operation, the loader transfer conveyor  78  accepts mail pieces  66  from the trays attached to the transport conveyor  86  as the intermediate containers  82  envelop the mail trays  68 . As discussed earlier, this is accomplished by overlapping the tray transport conveyor  86  and loader transfer conveyor  78  with matched horizontal velocities. In the initial overlap, the mail tray  68  is oriented right side up with an inverted intermediate container  82  positioned over its top. The enveloping mail conveyors  86  and  78  are synchronously transported through 180° of directional change through the vertical axis. This change of direction renders each mail tray  68  inverted and the intermediate container  82  upright. During the directional change of the mail conveyors  86  and  78 , the mail tray  68  is inverted and the mail  66  is transferred by gravity to the intermediate container  82 . 
     Once the mail has been transferred to the intermediate container  82 , it is then drawn into a uniform and limited compression mail stack  67 . This is achieved by implementing a mail compressing system  148  as illustrated in FIG. 31 into the intermediate container  82 . The mail compressing system  148  will then gather the mail  66  in a controlled manner into a consolidated mail stack  67 . Compression of the mail stack  67  is controlled to a fixed value by use of a limiting device regulating the maximum force which can be reacted through the mail stack  67  and front wall  180  (FIG. 23, of the intermediate container  82 . 
     After drawing the mail into the consolidated mail stack  67 , the mail stack  67  is measured to determine whether its size exceeds the capacity of a single cartridge  70 . If the mail stack  67  is measured to exceed the capacity of a cartridge  70 , it is engaged by a mail dividing system  150  (FIG. 23) that separates the stack into two mail stacks  67  contained within the intermediate container  82  and provides face support to the split mail stacks  67 . 
     Transfer of mail from the loader transfer conveyor  78  to one or two cartridges  70  occurs as a cartridge or cartridges  70  envelop the intermediate container  82 . Again, this is accomplished by overlapping the loader transfer conveyor  78  and the loader cartridge section  80  with matched horizontal velocities. In the initial overlap, an intermediate container  82  is oriented right side up with an inverted cartridge  70  over the top of the intermediate container  82 . Again, the enveloping mail conveyors  78  and  80  are synchronously transported through 180° of directional change through the vertical axis. The change of direction renders the intermediate container  82  inverted and the cartridge  70  upright. During this directional change, the intermediate container  82  is inverted and mail  66  is transferred by gravity to the cartridge  70  in the same orientation as it was originally delivered to the cartridge loader  62 . 
     As seen in FIGS. 21 and 22, the loader transfer conveyor  78  utilizing the powered chain conveyor system  74  has two parallel side tracks  108  for housing opposing conveyor chains  110 . The conveyor chains  110  have mounting brackets  118  for the attachment of the intermediate containers  82  to the loader transfer conveyor  78 . As illustrated in FIGS. 22 and 30, the intermediate containers  82  are attached to the loader transfer conveyor  78  in the same maimer as the engaging carriages  102  are attached to the tray transport conveyor  86 , except that the intermediate containers  82  are rigidly affixed to the mounting brackets  118  by attachment plates  142  extending from the ends of the intermediate containers  82 . 
     Similar to the engaging carriages  102 , the intermediate containers  82  can also be mounted directly to the belt of a powered flat belt conveyor  72 . If mounted on the belt of the powered flat belt conveyor  72 , the body design of the intermediate container  82  would provide for the attachment of the intermediate containers  82  to the belt of the conveyor  72  and to prevent any mechanical mechanisms on the intermediate containers  82  from interfering with the powered flat belt conveyor  72 . 
     As shown in FIG. 20, the intermediate containers  82  of the loader transfer conveyor  78  may consist of solid containers  144  or, if the cartridges  70  used for processing are smaller than the mail trays  68  being unloaded into the intermediate containers  82 , the intermediate containers  82  may be designed to split the stack of mail  66  into two stacks for the subsequent deposit of the mail stacks  67  into two separate cartridges  70  as illustrated in FIG.  1 . 
     Each intermediate container  82  designed to split the mail stack  67  into two stacks comprises a mail compressing system  148 , a mail dividing system  150  and a width adjustment system  152 . The mail compressing system  148  compresses the mail  66  toward the front wall  180  of the container  82 . The mail dividing system  150  then takes all the mail  66  in excess of the amount of mail  66  that can be deposited into one cartridge  70  and separates that excess mail  66  into a separate stack for deposit in a second cartridge  70 . The width adjustment system  152  adjusts the width of the side walls  164  of the intermediate container  82  so that the side walls  164  of the intermediate container  82  can envelop the top of a mail tray  68  and then also fit within the walls of a processing cartridge  70 . A detailed description of the mail compressing system  148 , mail dividing system  150  and the width adjustment system  152  is found below. 
     a. Mail Compressing System  148   
     The mail compressing system  148  of the present invention is shown in FIGS. 22 through 34. The mail compressing system  148  of the intermediate container  82  comprises (1) a paddle  154 ; (2) a shaft housing  156 ; (3) a paddle drive shaft  158 ; (4) a belt  168 ; and (5) a drive mechanism  170 . As seen in FIGS. 22 through 34, the paddle  154  extends across the width of the intermediate container  82  between the side walls  164  of the intermediate container  82 . Initially, when the intermediate container  82  first receives the mail  66 , the paddle  154  acts as the rear wall of the intermediate container  82 . Thus, all the mail  66  is deposited between the paddle  154  and the front wall  180  of the intermediate container  82 . 
     As seen in FIGS. 22 through 25, the intermediate container  82  has a longitudinal slot  160  in the base  162  of the intermediate container  82  that runs along the longitudinal axis of the intermediate container  82  at its center. The longitudinal slot  160  begins near the front wall  180  of the intermediate container  82  and extends the approximate length of the side walls  164  of the intermediate container  82 . This longitudinal slot  160  allows for the movement of the paddle  154  forward and backward along the intermediate container  82 . 
     As seen in FIGS. 30,  31  and  34 , the paddle  154  is pivotally connected to a shaft housing  156  (FIG. 31) by a formed bracket  176 . As illustrated in FIG. 31, the shaft housing  156  extends from the surface of the base  162  of the intermediate container  82 , where it pivotally connects to the paddle  154 , through the longitudinal slot  160  in the intermediate container  82 . Directly underneath the longitudinal slot  160  in the intermediate container  82  is a shaft  158 , which extends the approximate length of the intermediate container  82 , and, as shown in FIG. 31, is attached to the underside of the intermediate container  82  by shaft hangers  166  positioned just before and just after the ends of the longitudinal slot  160 . 
     As shown in FIG. 31, gears or sprockets  172  are located just beyond each end of the shaft  158  and maintained against the underside of the intermediate container  82  by brackets. These gears  172  drive a belt  168  that is attached to the shaft housing  156 . The belt  168  completely encompasses and rotates about the shaft  158 , shaft housing  156  and the shaft hangers  166 . Because the belt  168  is attached to the shaft housing  156 , the belt  168 , as it rotates, moves the shaft housing  156  along the shaft  158  which in turn moves the paddle  154  forward and rearward along the intermediate container  82 . When the paddles  154  move forward, this causes any mail  66  between the paddle  154  and front wall  180  to be compressed against the front wall  180  of the intermediate container  82 . 
     As seen in FIGS. 22 and 33, the gears  172  of this mail compressing system  148  are driven by a rubber pulley  174  sharing the same drive shaft as the rear gear  172  of the intermediate container  82 . The rubber pulley  174  engages a guide rail  178  (FIG. 22) located at predetermined points along the tracks  108  of the loader transfer conveyor  78 . When engaged, the rubber pulley  174  rotates, causing the rear gear  172  to rotate and move the belt  168  about the mail compressing system  148 . The rubber pulley  174  and rear gear  172  mechanism are also equipped with a slip clutch (not shown) to adjust the compressive force that exerts on the mail stack  67 . 
     In operation, the rubber pulley  174  comes in contact with a guide rail  178  shortly after mail  66  is deposited from a mail tray  68  into an intermediate container  82 . This guide rail  178  then rotates the rubber pulley  174  in the direction that causes the paddle  154  to move forward along the intermediate container  82  and compress the mail  66 , within the pressure parameters established by the slip clutch. After the mail  66  in the intermediate container  82  is emptied into a cartridge  70 , a second guide rail  178  will engage the rubber pulley  174  to rotate the rubber pulley  174  in the opposite direction to retract the paddle  154  to its home position toward the rear of the intermediate container  82 . 
     Additionally, the paddle  154  may be designed with a signal flag (not shown) that can be used to measure the amount of mail  66  in a given intermediate container  82  and then communicate that information with the loader cartridge section  80  so that the loader cartridge section  80  can determine whether to send one or more cartridges  70  to meet the intermediate container  82 . To determine the amount of mail  66  in a intermediate container  82 , this signal flag may be positioned to block a sensor pair, running perpendicular to the direction of intermediate container  82  movement, at a predetermined point along the loader transfer conveyor  78 . After blocking the first sensor pair, the signal flag blocks a second sensor pair that is positioned at an angle relative to the track conveyor. Since the intermediate containers  82  will run at a constant linear velocity, the amount of mail  66  in an intermediate container  82  can be determined by the amount of time it take for the signal flag to block the second sensor pair relative to the first. 
     With this information, the loader cartridge section  80  can not only determine whether to send one or more cartridges  70  to meet the intermediate container  82  but can also determine the necessary positioning of an adjustable paddle  175  in each cartridge  70 . As seen in FIG. 1, each cartridge  70  may be designed with an adjustable paddle  175  that adjusts the volume of space in each cartridge  70  dedicated to receive the mail pieces  66 . Thus, by knowing in advance the amount of mail  66  to be deposited in each cartridge  70 , the loader cartridge section  80  can adjust the paddle  175  in each cartridge  70  according the amount of mail  66  to be transferred from an intermediate container  82  into the cartridge  70 . 
     Finally, the intermediate container  82  may also be equipped with a mechanism that prevents the mail dividing system  150  from attempting to divide a mail stack  67  when there is not enough mail  66  in the intermediate container  82  to warrant a division of the mail stack  67 . This could be triggered through the same mechanism used above to communicate with the loader cartridge section  80  or could be accomplished mechanically by preventing the mail dividing system  150  from activating if the paddle  154 , as it compresses the mail stack  67 , passes a certain point on the base  162  of the container  82 . 
     b. Mail Dividing System  150   
     The mail dividing system  150  of the present invention is illustrated throughout FIGS. 23 through 46. The mail dividing system  150  generally comprises a separating platform  182  and a finger assembly  184 , which function together to separate the mail  66  into separate stacks  67  for the subsequent deposit of the mail  66  into two separate cartridges  70 . 
     As seen in FIGS. 35 and 36, the intermediate container  82  of the present invention is designed to have an opening  181  in the rear portion of the container  82  for housing the separating platform  182  of the dividing system  150 . As also seen in FIGS. 25,  26 ,  35  and  36 , the intermediate container  82  has two angular brackets  186  that are positioned parallel to one another and span almost the entire longitudinal length of the container  82 . As seen in FIG. 25, these brackets  186  are each positioned on the underside of the intermediate container  82  so that they are just within the longitudinal edges of the opening in the rear of the container  82  and exposed by the opening. As illustrated in the drawings, it is these angular brackets  186  that slideably mount and maintain the separating platform  182  in relation to the base  162  of the intermediate container  82 . 
     FIG. 23 illustrates a plan view of the intermediate container  82  as it appears with the separating platform  182  housed in the rear opening of the container  82 . As also illustrated by FIG. 23, the separating platform  182  does not span the entire length of the rear opening in the container  82  when held within the intermediate container  82 . Rather, a space  183  is intentionally left behind the separating platform  182  so that the platform  182  can retract away from its original position toward the rear of the container  82  to separate one mail stack  67  from the other. 
     As best shown by FIGS. 37 through 42, the separating platform  182  is comprised of an upper plate  188  and a lower plate  190 . The lower plate  190  is smaller in width than the upper plate  188  and, as illustrated by FIGS. 41 and 42, is slideably connected to the upper plate  188  by opposing guides  202  located on the underside of the upper plate  188 . As seen in FIGS. 37,  39 ,  40  and  43 , the lower plate  190  has spring loaded finger supports  204 , equipped with roller tips  206 , and intervening belting support bars  208  extending from the front end of the lower plate  190 . Furthermore, the lower plate  190  has pivotal pawls  210  extending downward at the rear of the lower plate  190 . As further explained below, these pawls  210  aid in sliding of the upper plate  188  toward the rear of the container  82  and away from the front portion of the lower plate  190  so as to expose the spring loaded finger supports  204  and belting support bars  208  used to divide the mail  66  into two stacks  67 . 
     As illustrated in FIGS. 39 through 40, the upper plate  188  of the separating platform  182  as two opposing plate side walls  192  that extend downward toward the underside of the base  162  of the container  82 . Additionally, the upper plate  188  has plastic strips  146  on its top surface that align with the plastic strips  146  located longitudinally across the base  162  of the container  82 . The plastic strips  146  on the surface of the base  162  and upper plate  188  aid in the movement of mail  66  along the base  162  of the container  82 . Furthermore, the upper plate  188  has a dividing cam roller  222  extending from the rear of the upper plate  188 . 
     As seen in FIGS. 25 and 42, the width of the upper plate  188  is such that the plate side walls  192  extend just past the angular brackets  186  attached on the underside of the base  162  of the intermediate container  82 . This allows the separating platform  182  to rest on the angular brackets  186  when positioned within the rear opening of the container  82 . 
     As illustrated in FIG. 39, the side walls  192  of the upper plate  188  have small holes for receiving a pin at the front and rear of the walls  192 . The holes on each wall  192  are aligned with one another and are used to pivotally and slideably connect the separating platform  182  to the angular brackets  186  of the container  82 . As shown in FIGS. 29 and 30, the separating platform  182  is connected at both sides to the angular brackets  186 . The separating platform  182  is connected at its rear by a platform pin  198  extending through the hole in the side wall  192  of the upper plate  188  and through a longitudinal slot  194  at the rear of the angular bracket  186 . At its front, the separating platform  182  is connected, at both sides, to the base  162  of the container  82  by a pivot arm  196 . The pivot arm  196  is connected at one end to the side wall  192  of the upper plate  188  and at the other end to the angular bracket  186  of the base  162 . 
     As shown in FIG. 28, the finger assembly  184  of the mail dividing system  150  is located directly underneath the front portion of the separating platform  182  when the platform  182  is in its home position, as illustrated by FIG.  29 . The finger assembly  184  includes two finger plates  212  connected together on a shaft extending through the angular brackets  186  and is pivotally connected at its ends to the underside of the base  162 . 
     As best seen in FIGS. 28 and 29, at the rear of each finger plate  212 , a portion of the plate  212  extends downward to engage a formed shaft  218 . The formed shaft  218  is held on the underside of the base  162  by bearings  220  attached to the angular brackets  186  of the base  162 . The shaft  218  is attached at one end to an extension bar  216  extending downward from the platform pin  198  that connects the side wall  192  of the upper plate  188  to the longitudinal slot  194  in the angular bracket  186 . 
     As also illustrated by FIG. 28, opposing pairs of stop bars  200  extend horizontally from the interior sides of the angular brackets  186  toward the center of the base  162 . The stop bars  200  are positioned on the angular brackets  186  so that they hold the pawls  210  extending downward from the lower plate  190  between the stop bars  200 . 
     FIGS. 44,  45  and  47  illustrate the operation of the mail dividing system  150 . In operation, the dividing cam roller  222  is forced to the rear of the container  82  by dividing guide rails (not shown) positioned on the track  108  of the loader transfer conveyor  78 . As the dividing cam roller  222  is forced rearward, the upper plate  188  of the separating platform  182  is also forced toward the rear of the container  82 . Because the upper plate  188  is slideably engaged at its rear along longitudinal slots  194  in the angular brackets  186 , the rear of the upper plate  188  slides rearward with the dividing cam handle  222 . However, because the front of the upper plate  188  is pivotally connected to the angular brackets  186  by a pivot arm  196 , the front of the upper plate  188  raises in the air about the pivot point. The paddle  154  of the compressing system  148  is allowed to elevate with the upper plate  188  of the separating platform  182  since the paddle  154  is pivotally connected to the shaft housing  156  of the compression system  148 . This is best illustrated by FIG.  30  and FIGS. 44,  45  and  46 . 
     In the meantime, the lower plate  190  is being held in its original position by the pawls  210  and the stop bars  200  extending from the angular brackets  186 . While the lower plate  190  is elevated with the upper plate  188 , the lower plate  190  does not move rearward, and thus, the upper plate  188  is slid away from the lower plate  190  exposing the spring loaded finger supports  204  and belting support bars  208  at the front of the lower plate  190 . Because the finger supports  204  are spring loaded, they rotate upward, as seen in FIG. 45, as the upper plate  188  moves away from the lower plate  190 . As shown in FIGS. 25 and 26, stop arms  221  may be positioned on the underside of the lower plate  190  to stop the motion of the upper plate  188  beyond a predetermined distance relative to the lower plate  190 . 
     Additionally, to assist in the separation of the mail  66  into two separate stacks  67 , the belting support bars  208  on the lower plate  190 , as seen in FIGS. 39,  44  and  45 , house belting strips  209  that are slideably attached to the underside of the upper plate  188 . As illustrated by FIGS. 44 and 45, when the upper plate  188  retracts away from the lower plate  190 , the belting strips  209  are lifted from of their housings on the belting support bars  208  and retracted rearward, with the movement of the upper plate  188 , at an angle that assists in the movement of the mail pieces  66  toward the rear of the intermediate container  82 . 
     At the same time as the upper plate  188  is being moved to the rear of the container  82 , the formed shaft  218  is also being moved to the rear of the container  82 . As the shaft  218  moves toward the rear, a bend in the formed shaft  218  engages the finger plates  212  of the finger assembly  184  and forces the finger plates  212  upward, as shown in FIG.  45 . As shown in FIGS. 44 and 45, stop arms  221  may also be connected to the underside of the base  162  that function to extend upward and beyond the surface of the base  162  of the intermediate container  82  when the separating platform  182  is initially retracted. These stop arms  221  help to prevent mail pieces  66  from falling through the gap created between the base  162  and separating platform  182  before the finger plates  212  contact the facing of mail pieces  66  at the front of the container  82 . Extension springs  214  (FIG. 29) connected to the finger plates  212  bring the finger plates  212  back to their original position once the formed shaft  218  is disengaged by the forward movement of the shaft  218  back to its original position. 
     When it is desired to return the separating platform  182  and finger plates  212  to their original position, the dividing cam roller  222  is forced back to its original position. The process is reversed in its entirety and the formed shaft  218  is disengaged from the finger plates  212 , retuning the finger plates  212  to their original position. 
     It is recognized by one skilled in the art that other dividing systems  150  may also be utilized to divide the mail stack  67  into two separate stacks  67 . For example, the mail stack  67  may be divided into two separate stacks  67  by mail splitter knives (not shown) that, in addition to separating the stack  67 , provide support to the back face of the mail  66  in the front portion of the container  82  and front face of the mail  66  in the rear portion of the container  82 . Once the mail stack  67  is divided, it is separated by diverting the rear portion of the container  82  with a cam mechanism. 
     c. Width Adjustment System  152   
     Additionally, to assist in the transfer of the mail  66  between the mail trays  68 , intermediate containers  82  and cartridges  70 , the intermediate containers  82  can also be designed to have adjustable side walls  164 . By having adjustable side walls  164 , the width of the intermediate containers  82  can be widened to envelop the mail trays  68  and subsequently reduce the width of the intermediate containers  82  to fit within the cartridges  70 . By having the intermediate containers  82  envelope the mail trays  68 , the transfer of the mail  66  into the containers  82  is smoother. Similarly, the transfer of the mail  66  from the containers  82  into the cartridges  70  is easier when the container walls fit within the walls  164  and  180  of the cartridges  70 . 
     The ability to adjust the width of the side walls  164  of the intermediate containers  82  is accomplished by a width adjustment system  152  which includes two opposing overlapping L-shaped brackets  144  each comprising a side wall  164  of the container  82  and a portion of the front wall  180  of the container  82 . Thus, the front wall  180  of the container  82  is split into two portions  179  and  181 . As seen in FIGS. 23 and 24, the portion of the L-shaped brackets  144  that form the front wall  180  of the container  82  overlap so that the first portion  179  of the front wall  180  overlaps the second portion  181  at approximately the center of the front wall  180 . This overlapping of the two portions  179  and  181  allows the length of the front wall  180  to increase as the side walls  164  move away from one another and decrease as the side walls  164  move toward one another. An illustration of an L-shaped bracket  144  is found in FIG.  47 . 
     As shown in FIGS. 33 and 47, each side wall  164  of the present invention is attached to the base  162 , at its sides, by rotating rods  230 . As illustrated by FIG. 33, each rotating rod  230  is attached to the exterior facing side of each side wall  164  by brackets  144 . As seen in FIG. 48, each rotating pinion shaft  226  is set in an eccentric mechanism  224 . The eccentric mechanism  224  is a round disk that rotates in both the clockwise and counter-clockwise direction and is set in the base  162  of the container  82  to be flush with the base  162 . 
     As further shown by FIG. 48, each rotating rod  230  is set off-center in the eccentric mechanism  224  so that when the eccentric mechanism  224  is rotated, the rotating rod  230  is moved vertically either forward or backward. Because each rotating rod  230  is affixed to the side wall  164  of the present invention, the movement of rotating rods  230  causes the side wall  164  of the container  82  to move both forward or backward in the vertical position. 
     Directly underneath the eccentric mechanism  224  is a pinion  226 , which is driven in both the clock-wise and counter-clockwise direction by a rack  232 . As illustrated by FIGS. 50 and 51, the pinion  226  and eccentric mechanism  224  are housed in a pinion housing  228  that is affixed to the underside of the base  162 . The pinion housing  228  has an elongated opening for receiving and maintaining the positioning of a rack  232  against the pinion  226 . Attached to the front end of each rack  232  is a cross bar assembly  234  that has an adjustment cam roller  236 . The adjustment cam roller  236  is designed to contact an adjustment guide rail  238  located on the track of the loader transfer conveyor  78 , as seen in FIG. 22, to move the cross bar assembly  234  and rack  232  in a forward and rearward motion. This forward and rearward motion of the rack  282  rotates the pinion  236  and eccentric mechanism  224 , causing the side walls  164  to move in opposing directions relative to one another. 
     As seen in FIG. 22, the eccentric mechanisms  224  are positioned directly underneath each side wall  164 . When the side walls  164  are in their home position, the rotating rods  230  are all positioned on the eccentrical mechanisms  224  toward the exterior edges of the base  162  of the container  82 . 
     In operation, the side walls  164  of the intermediate container  82 , when in their home position, are at their greatest width and able to envelop a mail tray  68 . Once the mail  66  is loaded in the intermediate container  82 , the width of the side walls  164  must then be decreased to fit within the side walls  164  of the processing cartridge  70 . Thus, prior to approaching the cartridge transport conveyor  250 , the adjustment cam roller  236  on the cross bar assembly  234  is engaged by an adjustment guide rail  238  extending from the upper track  108  of the loader transfer conveyor  78 . This adjustment guide rail  238  is formed to force the cross bar assembly  234  forward, causing the racks  232  under each side wall  164  to rotate the pinions  226  and eccentric mechanisms  224 . To move both walls  164  vertical toward the center of the container  82 , the eccentric mechanisms  224  on side wall  164  are rotated in the clockwise direction and the eccentric mechanisms  224  on the opposing side wall  164  are rotated in the counterclockwise direction to move all the rotating rods  230  so that they are positioned toward the front wall  180  of the container  82 . 
     After the mail  66  is deposited into the processing cartridges  70 , the side walls  164  of the container  82  are then moved back to their home position by a second adjustment guide rail  238  located on the lower track  108  of the loader transfer conveyor  78  that forces the adjustment cam roller  236  and cross bar assembly  234  rearward. Moving the bar assembly  234  rearward rotates the pinions  226  and eccentric mechanism  224  so that the rotating rods  230  are again positioned toward the exterior edges of the container  82 . 
     It is recognized by one skilled in the art that the amount of movement of the side walls  164  is dictated by the diameter of the eccentric mechanism  224  and the positioning of the rotating rod  230  on the eccentric mechanism  224 . Thus, if a larger range of movement between the side walls  164  is required, a larger diameter eccentric mechanism  224  is utilized and the rotating rod  230  is positioned as near the circumference of the eccentric mechanism  224  as possible. Similarly, it is recognized that positioning of the eccentric mechanism  224  and rotating rod  230 , relative to the side walls  164  may vary as well as the home positions of the opposing eccentric mechanism  224  without effecting the overall functionality of the width adjustment system  152 . 
     3. Loader Cartridge Section  80   
     As shown in FIGS. 1 and 52, the loader cartridge section  80 , similar to the loader tray section  76 , comprises three components: (1) a cartridge input conveyor  240 ; (2) a cartridge transport conveyor  242 ; and (3) a cartridge output conveyor  244 . The loader cartridge section  80  of the present invention is very similar to the loader tray section  76  of the present invention, except that it operates in the opposite direction. The loader tray section  76  receives empty cartridges  70  from the TMS via the cartridge input conveyor  240 , engages and transports the cartridges  70  along the cartridge transport conveyor  242  where the cartridges  70  are interfaced with the intermediate containers  82  to receive mail  66 , and then transported to an intermediary processing operation  93  (FIG. 54) via the cartridge output conveyor  244 . Substantially the same component parts found on the loader cartridge section  80  are present on the loader tray section  76 , and therefore, only a brief discussion of the three component parts of the loader cartridge section  80  is found below. 
     a. Cartridge Input Conveyor  240   
     As discussed previously, empty cartridges  70  are supplied to the cartridge input conveyor  240  by the TMS and are carried to the cartridge transport conveyor  242  on a powered roller conveyor  90 . The powered roller conveyor  90  transports the empty cartridges  70  to an area adjacent to and atop the cartridge transport conveyor  242 . As seen in FIG. 1, the cartridge input conveyor  240  brings the cartridges  70  to the cartridge transport conveyor  242  open end first with the open end registered to one side to coincide with the edge of the cartridge transport conveyor  242 . 
     Upon receiving information from the loader transfer conveyor  78  regarding the need for a cartridge  70  and the number of cartridges  70  required (one or two), the cartridge input conveyor  240  actuates a pusher finger  94  on finger belt conveyor  96  to advance the cartridges  70  onto the cartridge transport conveyor  242  in synchronization with an engaging carriage  102  located on the cartridge transport conveyor  242 . 
     b. Cartridge Transport Conveyor  242   
     Similar to the tray transport conveyor  86 , the cartridge transport conveyor  242  consists of a series of engaging carriages  102  located at fixed pitch points along the conveyor  242 . The engaging carriages  102  on the cartridge transport conveyor  242  are the same construction as the engaging carriages  102  on the tray transport conveyor  86  and are therefore designated by the same reference number. Likewise, the engaging carriages  102  are affixed to the conveyor  242 , regardless of type of conveyor, in the same manner as they are affixed to the tray transport conveyor  86 , described above. 
     The engaging carriages  102  of the cartridge transport conveyor  242  engage and maintain each cartridge  70  in pivotal attachment with the cartridge transport conveyor  242  in the same manner as the engaging carriages  102  maintain the mail trays  68  on the tray transport conveyor  86 . The only difference between the cartridge transport conveyor  242  and the tray transport conveyor  86  is the location where the cartridge  70  and mail trays  68  are engaged and the number of engaging carriages  102  utilized on the conveyor  242 . 
     In a case where the mail stack  67  is not split, only one cartridge  70  is transferred to the cartridge transport conveyor  242 . However, in a case where mail  66  will not fit into one cartridge  70 , two cartridges  70  will be advanced toward the cartridge transport conveyor  242 . Therefore, two engaging carriages  102 , or one engaging carriage  102  having multiple engaging mechanisms  100 , are required. 
     As the cartridges  70  move along the cartridge transport conveyor  242 , mail  66  is transferred from the intermediate containers  82  on the loader transfer conveyor  78  to the cartridges  70  on the cartridge transport conveyor  242 . After receiving the transferred mail  66 , the cartridges  70  are then conveyed to the cartridge output conveyor  244 . However, before transfer of the cartridge output conveyor  244 , the gripper paddle  130  on the engaging carriage  102  is released and pivoted downward to allow the cartridge  70  to be transferred to the discharge section. 
     c. Cartridge Output Conveyor  244   
     The cartridge output conveyor  244  consists of a powered roller conveyor  90  that receives the loaded cartridges  70  from the cartridge transport conveyor  242 . A finger belt conveyor  96  with pusher fingers  94  is used to move the cartridge(s)  70  quickly away from the cartridge transport conveyor  242  to make room for the next incoming cartridge(s)  70 . Once on the cartridge output conveyor  244 , the loaded cartridges  70  are then passed to the intermediary processing operation  93  via a powered roller conveyor  90 . 
     B. Cartridge Unloader  64   
     As seen in FIGS. 3 and 4, the cartridge unloader  64 , similar to the cartridge loader  62 , consists of an unloader cartridge section  246 , an unloader transfer conveyor  254  and an unloader tray section  256 . As mentioned previously, the cartridge unloader  64  operates substantially like the cartridge loader  62 , except that the intermediate containers  82  of the cartridge unloader  64  do not include a device to divide the mail  66  into two stacks. All the other component parts, however, on the cartridge unloader  64  are found on the cartridge loader  62  and have been described in detail above. Because substantially all of the parts in the cartridge unloader  64  are present in the cartridge loader  62 , the same reference numbers will be used to represent corresponding parts and only a brief discussion of the cartridge unloader  64  and its component parts is found below. 
     1. Unloader Cartridge Section  246   
     As seen in FIGS. 3 and 4, the unloader cartridge section  246  operates substantially like the loader tray section  76  of the cartridge loader  62 , except that the unloader cartridge section  246  transports cartridges  70 , rather than trays  68 . The unloader cartridge section  246  can be broken into three component parts: (1) a cartridge input conveyor  248 ; (2) a cartridge transport conveyor  250 ; and (3) a cartridge output conveyor  252 . 
     The cartridge input conveyor  248  feeds individual cartridges  70  containing processed mail  66  to the cartridge transport conveyor  250  via a powered roller conveyor  90 . The cartridges  70  on the cartridge input conveyor  248  are aligned with the cartridge transport conveyor  250  and advanced toward the conveyor  250  by a finger belt conveyor  96  having pusher fingers  94  which operate at the properly synchronized time. The cartridges  70  are then engaged by an engaging carriage  102  located on the cartridge transport conveyor  250 . Once engaged, the cartridges  70  are moved to a position where they are enveloped by an intermediate container  82  on the unloader transfer conveyor  254 , and inverted 180 degrees so that the mail  66  inside the cartridges  70  is deposited into the intermediate container  82  under the influence of gravity. After the mail  66  has been transferred from the cartridges  70  to the mail trays  68 , the empty cartridges  70  are released from the engaging carriage  102  and transported to the cartridge output conveyor  252 . 
     The cartridge output conveyor  252  has a finger belt conveyor  96  with pusher fingers  94  for advancing the empty cartridge  70  onto a powered roller conveyor  90  that transports the empty cartridge  70  back to the TMS. 
     2. Unloader Transfer Conveyor  254   
     The unloader transfer conveyor  254  operates substantially like the loader transfer conveyor  78  and has all the same components parts as the loader transfer conveyor  78 , except that the intermediate containers  82  are not equipped with a mail dividing system  150 . The mail  66  being deposited into the intermediate containers  82  is transferred from the intermediate containers  82  back into mail trays  68 , and thus there is no need for a mail dividing system  150  in the intermediate containers  82  of the unloader transfer conveyor  254 . The compressing system  148  and width adjustment system  152 , previously described, however, are both incorporated into the intermediate container  82  of the unloader transfer conveyor  254 . 
     Additionally, the adjustment of the width of the side walls  164  must be made so that the side walls  164  of the intermediate container  82  envelop the cartridge  70 . Subsequently, the width between the side walls  164  must be adjusted so that the side walls  164  of the intermediate container  82  fit within the mail tray  68 . This requires the positioning of the adjustment guide rails  238  on the track  108  of the unloader transfer conveyor  254  to be modified as compared to the loader transfer conveyor  78 . 
     Similar to the loader transfer conveyor  78 , the unloader transfer conveyor  254  can have a signal flag (not shown) attached to the paddle  154  of the compressing system  148  that can determine, through the use of a series of sensor pairs, the amount of mail  66  in the intermediate container  82 . A mail tray  68  that meets the size requirements of the mail stack  67  in the container  82  can be selected by the unloader cartridge section  246  for interfacing with the intermediate container  82 . 
     3. Unloader Tray Section 
     As seen in FIGS. 3 and 4, the unloader tray section  256  operates substantially like the loader cartridge section  80  of the cartridge loader  62 , except that the unloader tray section  256  transports trays  68 , rather than cartridges  70 . Like the loader cartridge section  80 , the unloader tray section  256  can be broken into three component parts: (1) a tray input conveyor  258 ; (2) a tray transport conveyor  260 ; and (3) a tray output conveyor  262 . 
     The tray input conveyor  258  feeds empty mail trays  68  to the tray transport conveyor  260  via a powered roller conveyor  90  positioned atop the tray transport conveyor  260 . The trays  68  on the tray input conveyor  258  are aligned with the tray transport conveyor  260  and advanced toward the conveyor  260  by a finger belt conveyor  96  having pusher fingers  94  at the properly synchronized time. The trays  68  are then engaged by an engaging carriage  102  located on the tray transport conveyor  260 . Once engaged, the trays  68  are inverted to envelop the intermediate container  82  and receive the processed mail  66  in the intermediate container  82  on the unloader transfer conveyor  254 . After the mail  66  has been transferred from the containers  82  to the mail trays  68 , the mail trays  68  are then released from the engaging carriage  102  and transferred to the tray output conveyor  262 . 
     The tray output conveyor  262  has a finger belt conveyor  96  with pusher fingers  94  for advancing the filled mail trays  68  onto a powered roller conveyor  90 . The powered roller conveyor  90  then transports the mail trays  68  for delivery to their next destination 
     While the present invention has been disclosed in reference to the disclosed embodiments, other arrangements will be apparent to those of ordinary skill in the art and are to be considered within the spirit and scope of the present invention. The invention is, therefore, to be limited only as indicated by the scope of the claims that follow and their equivalents.