Abstract:
A system and method are set out for automatically extracting pods from a carousel shaped casing tower which include elements for engaging and moving the pods within the carousel while the carousel maintains its place. The pods travel on a track within the carousel which comprises six layers of pods. The extracting is performed in an extraction zone which may be located at least one end of the carousel while the loading of pods occurs at other locations. The pods include pockets for accommodating articles. The articles may be mail pieces.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application claims priority to provisional patent application 60/499,612, filed on Sep. 3, 2003, which is herein incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to article handling systems and methods and more particularly to a system and method for article extraction which provides a decrease in cost and an increase throughput efficiency over related prior art systems. As used throughout the application, articles refer to mail items, magazines, books and other such flat items. It is however within the scope of the present invention that other articles, as would be imagined by one skilled in the art, may be included in the definition of articles. 
   There are typically three main steps in article sorting: article singulation, article transportation to separate out output bins corresponding to appropriate destination addresses, and article extraction from the output bins to other devices for further handling. Such further handling may include polywrapping, re and/or further sorting, and other handling. The present invention is an improvement in the area of article extraction. However, in order to appreciate the scope of the present invention it is necessary to analyse the entire system and method employed in achieving the above mentioned advantages. To this end, a brief look at prior art systems and methods for article handling is useful. 
     FIG. 1  depicts a Pocket Sorter system which provides for simple merging with manual and/or DPS mail, the possibility of any kind of packaging at the end, and a simple sorting algorithm. This design&#39;s disadvantages include a tremendous number of active and controlled pockets, the necessity for an article sequencing process, and a short time window because of the late arrival time of sequenced articles. In operation, articles  10  arrive from an external feeder and scanner (depicted by arrow  12 ) into select individual pockets  14 . The articles are then sorted into appropriate sections  16  of collection belt  18 . Belt  18  is an endless loop about two rotating means  11  facilitating belt movement in the direction indicated by arrow  11 . Provision is made for manual sorting  13  of articles on the belt  18  as well. The articles  10  are polywrapped  15  and stacked in a tray  17  for further processing. 
     FIGS. 2   a  and  2   b  depict a flat bed sorter arrangement which provides lower throughput performance per loading point, simple automatic emptying and packaging with mail compressing, and no need for autonomous vehicle technology because of the flat bed pockets. Disadvantages of the flat bed sorter include one shuttle loading point for each level of casing sections, greater length of shuttle track system in the casing sections, and existing impact of mail mix-grade and volume conditions on throughput. In operation, articles are introduced at respective feeders  20 ,  22  and transported  24  to endless sectioned ( 26 ) belts  28  which receive the articles  21  and stack them into trays  23 . The design has a width ( 25 ) of about 23 meters and the belts are spaced about 150 mm apart. 
   The transporting of cartridges and/or articles is also disclosed in the prior art as exemplified by U.S. Pat. No. 6,135,697.  FIG. 3  depicts a transport system  30  comprising a robotic arm  32  travelling along track  34  for affecting delivery of cartridge(s)  36  and/or articles  38  to appropriate compartments  31 . The transport system  30  comprises a sorter  33  and autofeeder  35 . The autofeeder  35  has several components including a feeding station  37 , jogging edging station  39 , queuing station  40 , and docking station  42 . Positioned atop the docketing station is a cartridge  36  filled with articles  38 . The robotic arm  32  is used to relocate the cartridge  36  to a select compartment  31  of compartment array  44 . The robotic arm  32  travels along a track  34  running parallel to the compartment array  31 . As may be required, a buffer shelf  46  is included having a plurality of buffer compartments  48  arranged in an array  41 . 
   The prior art systems rely upon a same device or combination of devices to both load and extract articles and/or cartridges from their respective storage areas. The device(s) must serve each storage area individually. Such loading and extraction processes are expensive and present engineering challenges. These and other burdens carry over into subsequent processes for article handling, including polywrapping, refeeding and the like. 
   SUMMARY OF THE INVENTION 
   It is an advantage of the present invention to provide a system and method for handling articles in a more efficient and cost effective manner than prior systems. Another advantage is to provide a system and method whereby post extraction processes are enhanced or at least maintained without additional burdens imposed by current extraction means. These and other advantages are achieved by the present system and method wherein stationary extraction zones are introduced and article storing compartments (PODs) are mobilized so as to be laterally displaced into the extraction zone where they, and the articles stored therein, are extracted. Within the extraction zone, post extraction functions are integrated with the extraction processes so as to maintain and/or increase efficiency and article throughput. The present system and method further define a loading zone that is different from the extraction zone. As such, it is possible to both load and extract while the carousel is not indexing. 
   The present system comprises a segmented casing tower arranged in a carousel design having two operating sections. A first operating section comprises at least one fixed tower portion having passages through which vehicles (ANTs) may pass and otherwise navigate to a select location and/or delivery point. A section operating section comprises at least one mobile casing accommodating a plurality of coaxial PODs therein. The PODs align with the vehicles and each are distributed over several levels. The first operating section further provides at least lateral support for the second operating section. Additionally, the casing tower provides support for both sections. 
   In operation, the ANTs pick up articles from feeders in a loading section, transport the articles by navigating the above passages to arrive at a particular POD. As the POD may be on one of several levels, ANT navigation is facilitated by various switches and lifts. Upon arrival at the POD, the ANT unloads an appropriate article(s) into the POD until the ANT&#39;s payload is empty. Once empty, the ANT returns to a loading section for the next payload. When extraction is desired, the carriers are indexed at least one length so as to relocate a carrier into the loading zone where the extraction occurs. 
   The extraction includes a platform on a lifting mechanism as well as POD engaging elements. The elements interface with mating receiving elements on the POD. In operation, the platform rises (or lowers) to the PODs level, the engaging elements engage and remove the POD from the carrier onto the platform. The platform then lowers (or raises) the POD to an appropriate level for further handling by post extraction processes. Such processes include polywrapping and manual handling. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The present invention and advantages thereof will be set out in more detail in the following detailed description taken in conjunction with the accompanying drawings wherein: 
       FIGS. 1–3  depict prior art systems; 
       FIG. 4  depicts a schematic top view of the present system; 
       FIG. 5  depicts a schematic cross section of the present system; and 
       FIG. 6  depicts an enlarged portion of the extraction zone. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 4  depicts a schematic overview of the present invention. As shown, the present system  100  includes a plurality of casing towers  102  arranged in a closed loop carousel  104  arrangement. One possible shape includes an oval. The components and functionality of the carousels are equivalent, therefore for clarity purposes, only one of the carousels will be described in detail with the understanding that the description applies to all carousels comprising the present system. The number of carousels is a matter of design. 
   The casing towers  102  are segmented. Each segment defines two portions, an outer static vehicle frame  101  and an inner carrier opening  103 . The casing tower includes two zones, a loading zone indicated by arrows  106  and an extraction zone indicated by arrow  108 . The loading zone runs along the length of the carousel, while the extraction zone is located at the carousel end or pinnacle. The casing tower  102  includes 6 vertical levels. The number of levels and zones is a matter of design. For example, the extraction zone  108  may be located at both carousel ends. 
   Outer frame  101  includes a number of vertically displaced coaxial vehicle passages equal to the number of levels of the tower  102  (in this embodiment six). The passages are sufficiently sized so as to accommodate a delivery vehicle or ANT  116  and a track  112  therein. The track  112  may be a monorail and the ANT may comprise sufficient means so as to run along the monorail. The ANTs may be autonomous and self powered. Alternative embodiments of ANTs may also be used in the present invention. The passage may additional include a floor upon which the ANTs may support themselves. The track runs about the casing tower  102  as well as connects the casing tower with other towers and two loading zones  114   a  and  114   b.  The track carrying ANTs from a loading zone to a tower is depicted as a solid line ( 112   a ), while the track carrying ANTs from a tower to a loading zone is depicted as a dashed line ( 112   b ). Inner carrier opening  103  defines an opening within casing tower  102  in which a plurality of carriers  110  run. The carriers run suspended from a track and connected to one another by linkages. The combination of linkages and track are labelled  111  and will be discussed in more detail with respect to  FIG. 5 . Each carousel includes a pair of opposing coq wheels  113 , designed to engage the carriers and, by rotating, laterally displace the carriers along their track. Each carrier includes article containers or PODs ( 145 ,  FIG. 5 ) equal to the number of levels of the tower (in this embodiment, six PODs). The PODs are vertically distributed within the carrier so as to align with each of the six levels of the tower  102  and vehicle passages. Each POD includes at least one pocket ( 160 ,  FIG. 6 ) to receive at least one article. 
   To facilitate lateral displacement of the ANTs, the system includes a plurality of switches  118 . To facilitate downwards displacement of the ANTs, the system includes divert elevators  120 . To facilitate upwards displacement of the ANTs, the system includes merge elevators  122 . 
   Delivery of an article to a pocket will now be described. An ANT approaches a loading station and receives articles to be delivered. The destination of the articles is known in advance. ANTs including articles therein are darkened ( 116   a ) and empty ANTs are depicted whited out ( 116   b ). Using loading zone  114   a  as a starting point, an ANT picks up articles and travels to a destination carousel (herein the middle carousel). The ANT  116   a   1  is fully loaded and travelling on one level  112   a.  The track outside the carousels runs on one level only. At switch  118 , the ANT  116   a   1  is horizontally diverted to the middle carousel. The ANT then encounters divert elevator  120  which vertically raises the ANT to the destination level—the level on which the destination pocket in the destination POD resides. Upon reaching the destination level, the ANT disembarks from the divert elevator  120  and runs along destination level track  112  until the ANT reaches its destination POD(s) and destination pocket(s) and unloads its cargo therein. The number of articles stored with the ANT varies by design. Assuming the destination pocket(s) to be along one side of the casing tower  102 , the ANT will empty its payload in a single pass leaving it now empty ( 116   b   1 ). The ANT then enters merge elevator  122  which raises the ANT to non-carousel track level thereby allowing ANT  116   b   1  to proceed to second loading zone  114   b,  along track  112   b,  to pick up a new payload and repeat the above steps and route. Should the ANT  116   a   1  require access to the other side of the carousel, it is horizontally diverted  118   a  to a short cut  115  and horizontally diverted again  118   b.  The ANT  116   a   1  once again makes deliveries until it is empty ( 116   b   2 ). This assumes the remaining pockets to be on this side of the carousel. If empty, the ANT  116   b   2  again enters a merge elevator  122  and is raised to non-track level  112   b  on the left side of the figure and proceeds back to loading zone  114   a.  Should the ANT be required to visit additional carousels during a single run it will be horizontally and vertically diverted as set out above. 
     FIG. 5  depicts a cross sectional view of the casing tower  102  along line A—A.  FIG. 5   a  depicts the cross section with a portion of the casing tower removed. As depicted, inner carrier opening  103  includes carrier  110  is suspended from track  130  via support means  132  comprising a cross brace  134  and two rollers  136  angled to rotatably engage track  130 . The support means further includes a pivot connection  138  with the top of the carrier  110 . Rail  130  rests upon a rail support  139  itself connected to a side  140  of the casing tower. Accordingly, the carrier  110  runs in the inner carrier opening  103  via the aforementioned support system. Alternatively, the support means, comprising like elements may be located below the carrier thereby supporting it from below. The carrier  110  includes six vertical co-axial PODs  145 . The static vehicle frame  101  remains fixed in place and defines six vertical co-axial vehicle passages  150 . Within each vehicle passage runs monorail  112  from which ANT  116  is suspended. Each vehicle passage, per level, is co-planar with a POD thereby facilitating delivery by the ANT to a POD. The static vehicle frame further includes a lateral support  142  frame in which a roller, suspended from carrier  110 , runs. Accordingly, the static frame, via lateral support  142 , provides for lateral guidance to the carrier  110 . 
   Extraction of a POD will now be discussed with reference to  FIG. 6 .  FIG. 6  depicts an enlargement of extraction zone  108 . As shown carousel  104  includes a plurality of carriers  110  comprising PODs  145  themselves comprising pockets  160 . A loaded ANT  116   a  delivers articles  170  arriving from divert elevator  120  running along track  112 , while an empty ANT  116   b  runs along track  112  enroute to a merge elevator  122 . Coq wheel  113  is depicted engaging carrier support  132 . Adjacent carriers  110  are coupled together via coupling  162 . The extraction zone  108  includes an extraction module  164  comprising a POD lift  166 . The POD lift includes means known in the art to rise and fall and align with a select level of the carousel. Additionally, the POD includes means for laterally displacing towards and away from the carousel as well as POD attaching elements for physically engaging the POD. Likewise, the POD includes mating means for mating with the engaging means of the POD. The aforementioned means may comprise any elements sufficiently engineered to accomplish the aforementioned and subsequent actions as would be known to one skilled in the art. 
   POD extraction occurs when no deliveries within the loading zone are made. Upon this occurrence, the coq wheel  113  is rotated so as to index the carriers by one carrier in the direction of coq wheel rotation. To facilitate movement of the carrier, the POD lift  166  is sufficiently spaced from the POD  10 . As depicted, POD  168  is introduced into the extraction zone proximate to the POD lift  166 . Once in place, article delivery in the loading zone may resume. The POD lift  166  extends and rises so as to align itself with a POD. The lift engages and retracts the POD from the carrier supporting it on the lift itself. The lift then displaces so as to bring the POD coplanar with the extraction module  164  whereupon the POD is removed from the lift and appropriately directed for further processing  172 . Further processing may include manual handling, polywrapping, and the like. 
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications would be obvious to on skilled in the art are intended to be included within the scope of the following claims.