Abstract:
A method and apparatus for sorting mail to delivery point sequence includes providing a first sortation assembly adapted to performing a first sort pass to mail articles supplied to it and a second sortation assembly adapted to performing a second sort pass to mail articles supplied to it. Mail articles are supplied to the first sortation assembly which identifies the mail articles and performs a first sort pass to sort the mail articles. The mail sorted by the first sortation assembly is conveyed to the second sortation assembly which performs a second sort pass to sort the mail articles to delivery point sequence depth of sort.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority from U.S. provisional patent application Ser. No. 60/146,689 filed on Aug. 2, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates generally to an article sorting method and apparatus and, more particularly, to sortation of mail. The invention is especially adapted to sort flat mail to delivery point sequence or carrier walk sequence, but may also apply to a mix of flat mail and letter mail. 
     Mail is received in a distribution warehouse from typically two sources. One is local mail which is to be delivered within the local area. This is known as turnaround mail. Local mail may also be sorted for delivery to other distribution centers. The other source of mail is out-of-area mail received from other distribution centers. Mail which is to be delivered locally must, ultimately, be sorted to delivery point sequence, also known as “carrier walk sequence.” A Dual Bar Code Sequenced (DBCS) machine is capable of achieving delivery point sequence for letter mail. However, it requires two or more passes of the mail through the same sequence. A first depth of sort is achieved with the first pass. The letters are then loaded into trays and the trays loaded onto manual carts. The trays are then unloaded from the manual carts and reprocessed during a second pass. An alternative to manual handling of the trays of mail between passes is disclosed in U.S. Pat. No. 5,385,243 which utilizes a storage and retrieval machine to stage the letter trays for the second pass. 
     Flat mail is mail which ranges in length of from 5 inches to 15 inches, height of from 6 inches to 12 inches, thickness of from 0.009 inches to 0.75 inches, and weight of from 0.01 pound to 1.0 pound. It may include paper envelopes, plastic wrappers, bound catalogs, banded newspapers, open mail pieces without wrappers, and the like. Such flat mail has traditionally been sorted to the distribution center level automatically, such as utilizing a model AFSM 100 flat sorting system manufactured by Mannesmann Dematic Postal Automation and marketed in the United States by Mannesmann Dematic Rapistan Corp. The sortation from distribution center to carrier walk sequence has traditionally been performed manually utilizing pigeon-hole bins. Such manual sorting of flat mail to the delivery point sequence may take several hours, up to half of the time available for a carrier to deliver his/her route. 
     It would be desirable to provide a carrier walk sequence for mail, especially for flat mail. It would be most desirable if the carrier walk sequence of flat mail is accomplished irrespective of source or type of the mail. In particular, it would be desirable to be able to sort turnaround mail to carrier walk sequence. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method and apparatus for sorting flat articles which is capable of sorting to delivery point sequence. The invention is capable of sorting to delivery point sequence irrespective of the source of the articles. 
     According to an aspect of the invention, an article sortation apparatus for sorting mail includes a first sortation assembly, a second sortation assembly, and a conveying assembly. The first sortation assembly includes a first induct, a first sortation mechanism which sorts articles from the first induct to a plurality of containers. The second sorting assembly includes a second induct, a second sortation mechanism which sorts articles from the second induct to an output. The conveying assembly conveys containers from the first sortation mechanism to the second induct. The first sortation assembly may be programmed to resolve the address of each article, apply a pseudo identification to the article, which is retained in a control, and sort the article to bins or containers. The second sortation assembly calls for containers from the first sortation assembly in the control by the first sortation assembly in a particular order and carries out a delivery point sequence sortation on the articles in those containers using the information stored in the control by the first sortation assembly. Preferably, the delivery point sequence sortation is to 9 zip code digits and, most preferably, to 11 zip code digits. 
     A method of sorting mail to delivery point sequence, according to another aspect of the invention, includes providing a first sortation assembly that is adapted to performing a first sort plan to mail articles supplied thereto and a second sortation assembly adapted to performing a second sort plan to mail articles supplied thereto. Mail is supplied to the first sortation assembly identified and sorted to bins or containers. The mail articles sorted by the first sortation assembly are supplied to the second sortation assembly in a particular sequence and sorted to delivery point sequence. 
    
    
     These and other objects, advantages and features of this invention will become apparent upon review of the following specification in conjunction with the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of a flat article sortation apparatus according to the invention; 
     FIG. 2 is a perspective view taken generally along the lines II—II in FIG. 1; 
     FIG. 3 is a perspective view taken generally from the direction III—III in FIG. 1; 
     FIG. 4 is the same view as FIG. 1 of an alternative embodiment thereof, 
     FIG. 5 is the same view as FIG. 1 of another alternative embodiment thereof; 
     FIG. 6 is the same view as FIG. 1 of yet another alternative embodiment thereof; 
     FIG. 7 is a perspective view of a tray handling system useful with the invention; and 
     FIG. 8 is a perspective view of the tray handling system in FIG. 7 from an opposite end. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now specifically to the drawings, and the illustrative embodiments depicted therein, a flat article sortation apparatus  10  includes primary sort assemblies  12   a  and  12   b  and a delivery point sequence (dps) sort assembly  14 . Each sort assembly  12   a ,  12   b  includes an induct  16  and a sortation mechanism generally illustrated at  18 . Sortation assembly  14  includes an induct  20  and a sortation mechanism  22 . A conveying assembly  24  interconnects outputs  26  of sortation assemblies  12   a ,  12   b  with induct  20  of sortation assembly  14 . The purpose of conveying assembly  24  is in order to convey containers of articles sorted by initial sortation assemblies  12   a ,  12   b  to induct  20  in order to induct the sorted containers for further sortation by subsequent sortation assembly  14  in a manner which will described below. 
     Each sort assembly  12   a ,  12   b  sorts mail received at induct  16 . An OCR-Optical Character Reader, VCS Video Coding System (OCR VCS) attempts to resolve the address to the full 11 digit zip code during the first pass on the primary sorting assembly  12   a ,  12   b . If the OCR/BCR (BCR-Bar Code Reader) cannot resolve the address to 11 digits, the VCS is used to complete the result. The address is resolved to 11 digits during the first pass. This information is retained by a high level sortation computer and used during the first and second pass operations. The OCR/VCS system connects the pseudo number with the 11 digit zip code. The primary sortation assembly  12   a ,  12   b  uses the 11 digit zip code to send the mail piece to the correct output during the first pass, so that it can be fed back through the second pass on dps sortation assembly  14  to the delivery point sequence. The mail piece must be sorted correctly (using the 11 digit zip code) each pass to be correctly sorted. Sortation mechanism  18  includes a carousel (not shown) which deposits articles into particular chutes  28  for depositing in containers  30  positioned under the chutes (FIG.  2 ). A tray handling system  110  discharges full trays automatically to output  26  which, in the illustrated embodiment, is a conveyor such as a belt conveyor, powered roller conveyor, or the like. A preferred form of tray handling system  110  is illustrated in FIGS. 7 and 8. In the illustrated embodiment, sortation assemblies  12   a ,  12   b  are flat-sorting systems marketed by Alcatel Postal Automation System and/or Mannesmann Dematic Rapistan Corp. under Model AFSM100. In the illustrated embodiment, each induct  16  includes three induct lines  32  and has 120 bin positions but may be extended up to 240 bins. 
     Therefore, each of the three induct lines  32  is capable of sorting to 40 possible bins. Each sortation assembly  12   a ,  12   b  is preferably capable of sorting up to 10,000 pieces of flat mail per hour and, most preferably, approximately 20,000 pieces of flat mail, or more, per hour. 
     Sortation assembly  14 , in the illustrated embodiment, is a dual-carousel system having 300 bins marketed by Mannesmann Dematic Postal Automation under Model TOPS2000. Mail can be sorted to each of the 300 bins from either of the dual carousels as fed by each of dual induct lines  34 . In the illustrated embodiment, details of sortation assembly  14  are disclosed in French Patent Application Nos. 9908610 filed Jul. 5, 1999, by Fabrice Darrou, Vincent Grasswill, Alain Danjaume, entitled Dispositif de convoyage d&#39; objets plats avec un systeme d&#39; aiguillage; 9909163 filed Jul. 15, 1999, by Jean-Luc Astier, Pierre Advani, Dino Selva, entitled Dispositif a plusieurs convoyeurs a godets superposes pour le tri d&#39; objets plats; 9907316 filed Jun. 10, 1999, by Fabrice Darrou, Vincent Grasswill, Robert Vivant, entitled Dispositif de convoyage de courrier avec des roues en matiere elastomere elastiquement deformables; Published International Patent Application WO 00/39010 published Jul. 6, 2000, by Francois Agier et al., entitled DEVICE FOR CONVEYING FLAT OBJECTS BETWEEN PROCESSING EQUIPMENT ITEMS; and Published International Patent Application WO 00/39012 published Jul. 6, 2000, by Francois Agier et al., entitled ROUTING DEVICE FOR GROUPING TWO STREAMS OF FLAT OBJECTS, SUCH AS MAIL ENVELOPES, INTO ONE STREAM; the disclosures of which are hereby incorporated herein by reference. Alternatively, sortation assembly  14  may use the principles disclosed in U.S. Pat. No. 5,718,312 adapted to flat mail sortation capability, the disclosure of which is incorporated herein by reference. Preferably, sortation assembly  14  is capable of sorting up to 20,000 flat articles per hour and, most preferably, up to approximately 40,000 flat articles per hour, or more. Preferably, sortation assembly  14  has a sort rate that is approximately double the sort rate of each sortation assembly  12   a ,  12   b  for reasons that will be set forth in more detail below. A tray return conveyor  25   a ,  25   b  returns empty trays from a dps sortation assembly to a respective primary sortation assembly  12   a ,  12   b.    
     As containers, or trays,  30  are dispatched from sortation assemblies  12   a and  12   b  according to the sort plan, they are conveyed by conveying assembly  24  to induct  20  of sortation assembly  14 . Conveying assembly  24  includes a series of transfer switches  36  which selectively transfer containers  30  onto spurs  38  leading to induct  20 . Transfer switches  36  are operated in coordination with the overall sortation plan in order to stage containers  30  at induct  20  in a sequence called for by sortation assembly  14 . The first pass primary sortation assembly  12   a ,  12   b  is used by the system to determine the address information. The system must learn how many letters are to be sent to each delivery point. The first machine, in addition to discovering address and mail piece information, starts the sorting process. Note that this first pass requires resolution to the delivery point level (11 digits for the US). During the first pass, all of the mail destined for the first delivery point of each route is sent to output  1 , the second delivery point to output  2 , and the third to output  3 , etc. After the first pass is concluded, the trays are then swept automatically from the sortation assembly  12   a ,  12   b  and sent to dps sortation assembly  14 , but only when sortation assembly  14  calls for each particular container. For correct delivery point sequencing, output  1  is processed before output  2 , which is processed before output  3 . During this second pass, mail for a first carrier route will be sent to output  1 , mail for another carrier route will be sent to output  2 , and mail for yet another carrier route will be sent to output  3 . This pass splits mail from the original output  1  (first delivery point regardless of route) between final outputs  1 ,  2 , and  3 . The same process is followed for original outputs  2  and  3 . The idea is to ensure that the delivery points in the stackers at the end of the first pass are in separate outputs at the end of the second pass. 
     As would be apparent to the skilled artisan, article sortation assembly  10  is capable of sorting turnaround mail, which is mail collected in a local area in which sortation assembly  10  is located and sorting the mail to the delivery point sequence at the output of sortation assembly  14 . 
     Each piece of mail is identified efficiently (to 11 digits) on the first pass, using OCRJVCS and a spray-on PSEUDO ID#, and sorts the mail in an efficiently balanced throughput scenario of approximately 17,000 pieces/hr (in balance with spray-on system and OCRIVCS delay). The product can now be called for in sequence (and processed) at a higher speed in the second pass (40,000 P/C hr). This allows for substantial reduction in labor and utilizes mail containers or cartridges that allow the efficient and timely input of dps sortation assembly  14 . The system maximizes, optimizes and balances the various levels of technology (for product ID, software and VCS delay) and captures the savings by allowing use of a high speed second pass. Various levels of technology may be integrated in an efficient (time-balanced) scenario, which addresses a complex series of process constraints to capture saving previously achievable. 
     The present invention advantageously utilizes the extremely fast sortation capacity of sortation assembly  14  by supplying articles initially sorted by sortation assemblies  12   a and  12   b , each of which has a lower capacity than sortation assembly  14 , but, when combined, are capable of supplying containers of first-pass sorted flat articles at a rate that utilizes the capacity of sortation assembly  14 . Additionally, mail may be transferred between sortation assemblies  12   a  and  12   b  and sortation assembly  14  in a highly automated manner. This avoids the necessity for loading mail into standard trays and loading the trays on manual carts, also known as Eastern Regional Mail Containers (ERMC). Advantageously, the present invention may utilize containers  30  that are of rigid construction such as rigid molded plastic, or the like, and bearing a permanent identification number which may be encoded by a plate attached to the container, which may be a bar code, radio frequency tag, or the like. This eliminates the necessity for applying temporary labels to each container dispatched from sortation assembly  12   a  and  12   b  as would be done if the containers were being dispatched to the transportation system. Rigid containers are feasible because containers  30  may be retained totally within sortation assembly  10  and not utilized to ship mail to other distribution centers. The utilization of rigid containers advantageously facilitates automatic transfer of flat articles from the containers at induct  20  to thereby further reduce manual processing of the flat articles to be sorted. 
     Flat articles that have been sorted to delivery point sequence by sortation assembly  10  may be dispatched to a transportation system utilizing the HIGH THROUGHPUT DISPATCH SYSTEM FOR MAIL PROCESSING AND DISTRIBUTION CENTER disclosed in International Application Ser. No. PCT/EP99/00317 filed Jan. 21, 1999, claiming priority from U.S. provisional patent application Serial No. 60/072,032 filed Jan. 21, 1998, the disclosures of which are hereby incorporated herein by reference. Sortation assembly  10  may also utilize the principles of DOCK-TO-DOCK RECEIVING AND DISPENSING FOR A POSTAL PROCESSING CENTER disclosed in commonly assigned provisional patent application Ser. No. 60/133,413 filed May 11, 1999, the disclosure of which is hereby incorporated herein by reference. 
     An alternative flat article sortation apparatus  10 ′ includes an input/output assembly  40  for conveyor assembly  24 . Input/output assembly  40  includes one or more lanes  42  which may transfer containers from an exterior source, such as a transportation system to feed the containers to induct  20  of sortation system  14 . Alternatively, input/output section  40  may transfer containers of flat articles that have been sorted by sortation assemblies  12   a  and  12   b  to a transportation system. This allows sortation assembly  10 ′ to dispatch to the transportation system trays of articles sorted by sortation assemblies  12   a  and  12   b  to the level of dispatch to other distribution/sortation centers. Accordingly, mail received at the distribution center in which sortation assembly  10 ′ is located can be inducted at induct  16  on each sortation assembly  12   a  and  12   b  and sorted to other distribution centers, as will be understood by the skilled artisan. This could be done either separate from or in combination with sorting turnaround mail to delivery point sequence with sortation assembly  14 . 
     Input/output  40  could additionally be utilized to input trays or containers of flat articles received from other distribution centers to be combined with trays of flat articles initially sorted by sortation assemblies  12   a  and  12   b  and finally sorted by sortation assembly  14  to delivery point sequence. This allows the output of sortation assembly  14  to handle both turnaround mail and mail originating from other distribution centers. The mail from other distribution centers could be sorted separately or in combination with locally collected mail in the area surrounding the distribution center in which sortation assembly  10 ′ is located. In sortation assembly  10 ′, conveying assembly  24  would utilize bidirectional transfer switches  36 ′ in order to provide transferring of articles to either induct  20  or to input/output  40  and visa versa. Transfer switches  30 ,  36 ′ are preferably of the type disclosed in commonly assigned provisional patent application Ser. No. 60/137,785 filed Jun. 4, 1999, entitled CONVEYOR TRANSFER ASSEMBLY, the disclosure of which is hereby incorporated herein by reference. 
     Preferably, dps sortation assembly  14  is capable of handling both flat articles, such as flat mail, and the smaller letter mail. With such capacity, it may be possible to merge not only flat mail from distribution centers remote from the distribution center in which sortation assembly  10 ′ is located, but also to insert letters such as from other such distribution centers or from other sorters such as a sorter dedicated to sorting letter mail. As such, the mail dispatched from the output of sortation assembly  14  may be integrated into individual bundles of both flat mail and letter mail for each household in order to further maximize the efficiency of each mail carrier while walking the mail route. 
     An alternative article sortation apparatus  100  is similar to sortation apparatus  10 , except that it includes a dps sortation assembly  14 ′ with an induct  20 ′ having only two induct lines  38 . By using rigid containers capable of automatic unloading, sortation assembly  14 ′ can be supplied with a sufficient quantity of articles utilizing only two induct lines. 
     Another alternative article sortation apparatus  100 ′ is shown having a single initial sortation assembly  12  for conducting an initial sort plan on the flat articles and a conveyor assembly  24  supplying the containers of initially sorted flat articles from sortation assembly  12  to dps sortation assembly  14 . In the illustrative embodiment, primary sortation assembly  12  has a capacity that is similar to that of subsequent sortation assembly  14 . Because the capacities of sortation assemblies  12  and  14  are relatively closely matched, only one primary sortation assembly  12  is supplied. 
     An example of a tray management system  110  that is useful with the invention is illustrated in FIGS. 7 and 8. However other tray management systems, including ones that are manual or semi-automatic, can be used. Automatic tray handling system  110  includes a plurality of conveying surfaces  116 , which are operable to move the trays  30  along one or both sides of the sorter units  12   a ,  12   b . A plurality of tray moving devices  120  are operable at respective sorter units  12   a ,  12   b  to pull empty trays  30  onto a tray support  172 , which supports the empty tray while the sorter system discharges sorted mail into the tray. After the tray is at least partially filled by the sorter unit, the tray moving device  120  is then operable to move the at least partially filled tray back onto the conveying surface. A continuous supply of empty trays is provided to the sorting units  12   a ,  12   b  and filled or at least partially filled trays are automatically discharged from the sorter units onto the conveying surface  116 . 
     An input end  111   a  of tray handling system  110  preferably provides one or more tray induct stations  138  and  140  for loading or inducting empty trays onto the tray handling system, while a discharge end  111   b  of tray handling system  110  provides a downstream operation, such as a labeling station  122  which is operable to label the trays as they are discharged from tray handling system  110  to output  26 . The sorter units  12   a ,  12   b  may each be arranged in a pair of rows, and the conveying surfaces  116  of automatic tray handling system  110  may extend around both sides of the rows of each sorter unit  12   a ,  12   b . However, the tray handling system  110  could be used with a single side of a mail sortation system which has one or more rows of sorter units. Empty trays  30  are movable in a continuous loop via conveying surfaces  116  and a pair of vertical tray moving or tray return devices  118  at one end of the tray handling system. 
     Conveying surface  116  includes a plurality of conveying surfaces. More particularly, conveying surface  116  preferably includes a pair of opposite upper conveyors  124  and  126 , a pair of opposite lower conveyors  128  and  130  and a pair of tray moving or return devices, such as incline or connecting surfaces or ramps  132  and  134 , which are operable to move empty trays from lower conveyor  128  to upper conveyor  126  and from lower conveyor  130  to upper conveyor  124 , respectively, at input end  111   a . A pop up belt transfer or  90  degree transfer  136  is positioned at each end of the incline ramps  132  and  134  to change the direction of travel of the trays  30  as they move from one of the lower conveyors to the respective incline ramp, and from the incline ramp to the respective upper conveyor. Such transfer units are commercially available and known in the art, such that a detailed discussion will not be included herein. Briefly, transfer units  136  are operable to convey a tray in a direction along the conveyor at which they are positioned, and may be operable to raise one or more belt conveyor strips to convey a tray positioned at the transfer unit in a direction which is generally transverse or normal to the conveyor direction. 
     Tray induct stations  138  and  140  are preferably positioned side by side one another. Preferably, tray induct stations  138  and  140  preferably include belt conveyors, which are operable to transport or convey an empty tray onto a corresponding 90 degree transfer unit  136   a  and  136   d , respectively. Empty trays may be manually loaded onto the induct stations to induct the empty trays into the conveyor system  116  of the automatic tray handling system  110  or may be automatically fed from a tray return conveyor  125   a ,  125   b . Preferably, tray induct station  140  includes an inclined belt conveyor, such that an input end  138   a  and  140   a  of the induct stations  138  and  140 , respectively, are positioned at substantially the same level for easy access and loading of empty trays onto the induct stations  138  and  140 . 
     Incline ramp  132  is connected between a pair of 90 degree transfer units  136   a  and  136   b  at a downstream end  128   b  of lower conveyor  128  and an upstream end  126   a  of upper conveyor  126 , respectively. Similarly, incline ramp  134  is connected between a pair of 90 degree transfer units  136   c  and  136   d  at a downstream end  130   b  of lower conveyor  130  and an upstream end  124   a  of upper conveyor  124 , respectively. 
     Trays  30  are conveyed along upper conveying surfaces  124  and  126  toward a downstream end  124   b  and  126   b , respectively. Vertical tray moving devices  118  are positioned near or at the downstream ends  124   b  and  126   b  to remove empty trays  30  from the upper conveyors and move the empty trays onto an upstream end  128   a  and  130   a  of the lower conveyors  128  and  130 , respectively, as discussed in detail below. Labeling stations  122  may be positioned at or near a discharge end  124   c  and  126   c  of upper conveyors  124  and  126 , respectively, and are operable to label the filled trays as they are conveyed toward output  26  of automatic tray handling system  110 . Preferably, one or both of the upper conveyor surfaces included a curved section  127 , such that the discharge ends  124   c  and  126   c  of upper conveyors  124  and  126 , respectively, are in close proximity, in order to reduce the manual labor of the system. A scanner  146  may be positioned at output  26  to verify the information contained on the label applied to the trays. A pair of reject conveyors  148  and  150  may be provided adjacent to discharge ends  124   c  and  126   c , respectively, to allow incorrectly labeled trays to be discharged to a separate area via respective 90 degree transfer units  136   e  and  136   f  and reject conveyors  148  and  150 . 
     Lower conveyors  128  and  130  are preferably operable in a reverse direction from upper conveyors  124  and  126 , to return the empty trays  30  back toward input end  111   a . The 90 degree transfer units  136   a  and  136   c  are positioned at downstream ends  128   b  and  130   b  of conveyors  128  and  130 , respectively, to move the empty trays onto the respective incline ramps  132  and  134  to transport the trays to the upper conveyors  124  and  126 , respectively, at the other side of the sortation system  13 . 
     In order to provide a continuous loop for the empty trays about the conveyor surfaces  116 , vertical tray moving devices  118  are positioned at downstream ends  124   b ,  126   b  of upper conveyors  124 ,  126  and upstream ends  128   a ,  130   a  of lower conveyors  128 ,  130 . Each vertical tray moving device  118  is operable to move an empty tray from the respective upper conveyor  124 ,  126 , lower the tray to the level of the lower conveyors  128 ,  130 , and then move the tray onto the respective lower conveyor  128 ,  130 . 
     Changes and modifications in the specifically described embodiments can be carried out without departing from the principles of the invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.