Patent Publication Number: US-2015083549-A1

Title: System and method for sorting articles

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application Ser. No. 61/501,538, filed Jun. 27, 2011, the contents of which are fully incorporated by reference herein. 
    
    
     BACKGROUND 
     The present disclosure is directed to a system and method for operating a sorting system, and more particularly to a system and method for configuring a sorting system 
     Sorting systems of the loop conveyor type are well known. Sorting systems, including loop conveyor sorting systems, have been adapted to sort articles such as mail, packages, luggage, and other discrete objects. Sorting systems of this type have been deployed in post offices, warehouses, retail distribution centers, airport terminals, and other locations where sorting operations are required. 
     What has been needed is a system and method of calibrating a sorting system that improves upon those available in the past. 
     SUMMARY 
     A method for calibrating a sorting system is disclosed having a number of carriers comprises providing a sensor on one of the carriers and passing the sensor across a number of divert locations. An index feature at each divert location is detected by the sensor and the logical position of each divert location is determined. The divert locations are then indexed to the logical position. 
     An apparatus for configuring a sorting system is also disclosed. The apparatus comprises a carrier tray having a sensor, wireless transmitter, and power supply mounted thereon. The sensor is configured to detect a divert location of the sorter system and the wireless transmitter is in communication with the sensor. The power supply is coupled to the sensor and wireless transmitter. 
     Also disclosed is a system for configuring a sorting system. The system comprises a conveyor for transporting articles from a load station to a number of offload stations, a number of divert locations for transferring the article from the conveyor to the offload station, a control system for activating the diverter at a predetermined time and a configuration tray removably attachable to the conveyor. The configuration tray includes a sensor for detecting the physical position of the diverter and a transmitter for communicating the position of each diverter to the control system. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top elevational view of a sorting system; 
         FIG. 2  is a side elevational view of an individual divert location; 
         FIG. 3  is a perspective view of a configuration tray; and 
         FIG. 4  is a flowchart illustrating the configuration and sorting operations. 
     
    
    
     DETAILED DESCRIPTION 
     Presently disclosed is a system and method of operating a sorting system and a system and method for calibrating or configuring a sorting system. 
     As illustrated in  FIG. 1 , a sorting system  20  comprises loop conveyor  22  with a number of carriers  24  allowing continuous operation and increased throughput of the system. Each carrier  24  is configured to transport an article to be sorted from at least one load station  30  to a preselected divert location  32 . In the embodiment illustrated, the loop conveyor  22  includes thirty (30) discrete carriers  24  and one load station  30 . However, it is contemplated that more or fewer discrete carriers  24  may be provided and additional load stations  30  may be provided. 
     Further according to  FIG. 1 , the loop conveyor  22  includes discrete carriers  24  each configured to transport a single article. The carriers  24  are shown to be tilt-type carriers that discharge the article to be sorted by tilting the tray at the divert location  32 . Alternatively, the carriers  24  may be tilt trays, tilt-shells, bomb-bay, hook conveyors, or other designs known in the art. The sorting system  20  is shown having discrete carriers  24 , however the term “carrier” should be understood to include discrete bins, each containing an article to be sorted; a continuous path, such as a conveyor belt, where each article to be sorted is not separately binned; and a sorter where each bin contains multiple items to be sorted. 
     Each divert location  32  includes a divert device  34  ( FIG. 2 ) for directing the article to be sorted from the carrier  24  to an output path, such as an inclined roller, bin, or other output. In  FIG. 2 , the divert device  34  is a lifting arm or other structure for engaging the tilt-tray type carrier  24  as the carrier  24  passes the divert location  32 . According to various alternative embodiments, the divert device  34  is a pusher, ram, movable wheel, or other device known in the art corresponding to the type of carrier  24  selected. 
     A central controller  36 , shown in  FIG. 1 , such as a programmable logic controller, computer-based software, hardware system, microcontroller, or other apparatus for receiving and transmitting electrical commands to the divert devices  34 , is also provided that includes an index of the logical position of each divert locations  32  and the preferred divert location  32  for an article to be supported. The controller  36  is in communication with divert devices  34  at each divert location  32  and is configured to transmit a signal to one or more divert devices  34  to engage the carrier  24  and direct the article to be sorted to an output path. 
     In order for the article to be sorted to be delivered accurately to a specific output at the divert location  32 , it is important to first calibrate the sorting system  20  by determining the logical position of the divert location  32  relative to a reference point, such as the load station  30  so that the divert device  34  is activated at the proper time. This calibration is performed in a calibration operation where the actual, physical location of the divert locations  32  is converted into a logical position of the divert location  32 . The logical position of the divert location  32  may be determined based on physical distance, time delay, angular displacement, electrical signal, or carrier index. 
     Once the logical position of the divert location  32  is determined the sorting system  20  may operate in a sorting mode. During the sorting mode, articles to be sorted are provided at a load station  30  and loaded into the carrier  24  and delivered to the divert location  32  where they are offloaded. 
       FIG. 2  illustrates an individual divert location  32  in further detail. Located at each divert location  32  is divert device  34  that engages individual carriers  24  to remove the article to be sorted from carrier  24 . Divert device  34  may be, according to various alternative embodiments, a tilt-tray, bomb-bay drop, sliding shoe, or other type of device, including pneumatic devices, for removing articles from carriers  24  to an output path. Each divert device  34  is individually accessible and selectively engagable by the controller  36  to release articles to be sorted from the carrier  24 . 
     Each divert location  32  includes an index feature  26  configured to be detected by a sensor  28  mounted to one or more carriers  24 . The index feature  26  may be a structural component of the divert device  34  or separate component. The sensor  28  located on the one or more carriers  24  may be a proximity sensor, optical sensor, electrical sensor, image detector, physical switch, or other type of apparatus capable of detecting and electrically communicating the presence of the index feature  26 . In one instance, the sensor  28  is an optical sensor that transmits and captures a beam of light reflected from the index feature  28 . In another instance, the sensor  28  is an electrical sensor that detects a certain frequency of electrical energy, such as from an RFID chip, and the index feature  26  is an RFID chip. In yet another instance, the sensor  28  is a physical switch, such as a lever or pushbutton, that is triggered by physical contact with the index feature  26 . In another instance, the sensor includes image or video capture software that searches for specific reference points, such as colored tags, that make up the index feature  26 . 
     Various methods of determining the logical position of each divert location  32  are contemplated. In a first method, the logical position of each divert location  32  is based on the index position of discrete carriers  24 . According to this method, each discrete carrier  24  is provided with a sequential index number in the direction of travel, from #0 to #29 in the embodiment illustrated in  FIG. 1 . The sensor  28  is provided at the first carrier  24 , index #0. As the carrier  24  travels from a reference point, such as load station  30 , the sensor  28  will detect the index feature  26  of each divert location  32 . The load station  30  is used as the reference point for illustrative purposes, however it is contemplated that other reference points may be used. 
     As the sensor  28  detects the index feature  26  of each divert location  32 , a signal, such as an electrical signal, is transmitted to the controller  36 . When the controller receives the electrical signal the index number of the carrier  24  located at the reference point is recorded. By way of example, the first divert location  32  may be detected when the carrier  24  indexed at #10 is located at the load station  30 . This allows a configuration lookup table to be developed, indexing each divert location to a carrier index. A sample of this configuration lookup table is demonstrated in the following Table 1: 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Load Station Index 
                 Divert Location 
               
               
                   
                   
               
             
            
               
                   
                 #10 
                 #1 
               
               
                   
                 #15 
                 #2 
               
               
                   
                 #18 
                 #3 
               
               
                   
                 #25 
                 #4 
               
               
                   
                   
               
            
           
         
       
     
     This table allows for the locating of divert locations  32  based on the index of the carrier  24  located at the reference or load station  30 . By way of example, when an item is loaded into the carrier  24  indexed at #0 that carrier will be at divert location #1 when the carrier  24  indexed at #10 is in the load station  30 . Additionally, the carrier  24  indexed at #0 will be at divert location #4 when the carrier indexed at #25 is at the load station  30 . An algorithm may be developed to determine the load station index for each carrier and divert location. This determination may be by means of a lookup table or by calculation. 
     Various other methods are also contemplated. According to one variation, rather than assigning a single index to a single discrete carrier  24  multiple index numbers may be assigned to a single carrier, or a single index number may be assigned to multiple carriers. According to another method, index numbers are not based on the carriers  24  but other reference sources. For example, a continuous drive train, such as a chain or conveyor, may be provided that connects and transports the carriers between the load station(s) and divert location(s). This continuous drive train may be indexed by links or sections. 
     Also contemplated are non-indexed methods of determining the logical position of the divert locations  32 . In one method, the logical position of each divert location  32  is provided based on the elapsed time between signals. This time delay may be converted into a distance measure or may be maintained as a time measurement. Finally, while it is preferred that the indexed locations of the divert locations  32  are communicated wirelessly to the controller  36 , it is also contemplated that the sensor  28  may communicate through a direct connection or may store the information and require an additional step, such as a plug-in connection or manual input, to communicate the logical position of each divert location  32  to the controller  36 . 
       FIG. 3  illustrates a configuration sorter tray  38  that is used to configure a sorter system  20  in a configuration operation according to the first embodiment. In this embodiment, the configuration sorter tray  38  includes a tray  40 , power supply  42 , wireless input/output  44 , and one or more laser photoeyes  46  with a beacon  48  for visible system feedback. The beacon  48  may be a lamp, laser, flag, or other signaling device providing user feedback. In the illustrated embodiment, the beacon  48  includes three lamps for indicating to a user (1) normal operation; (2) detection of a divert location  32 ; and (3) errors. In the illustrated configuration sorter tray  38 , the laser photoeye  46  projects a laser that is reflected from the index feature  26  back to the photoeye  46 . 
       FIG. 4  is a flowchart illustrating a method for sorting articles in a sorting system  20  from a load station  30  to an output path. 
     As shown in  FIG. 4 , the sorting system  20  includes a configuration operation and a sorting operation. The configuration operation is provided to determine the logical positions of various divert locations  32  relative to a reference point, such as the load station  30 . This operation may be run during the set-up of the sorting system  20 , when divert locations  32  have been added, removed, or moved in the system  20 , or whenever re-calibration is necessary. The sorting operation is provided for normal operation of receiving, detecting, and delivering articles to be sorted from a load station  30  to a preferred divert location  32 . 
     During the configuration operation, the configuration sorter tray  38  is placed on the loop conveyor  22  of the sorting system  20  replacing one of the carriers  24 . As the configuration sorter tray  38  passes each divert location  32 , the sensor  28 , such as laser photoeye  46 , detects the presence of the divert device  34  or other index feature  26 . The presence of the index feature  26  is communicated via the wireless I/O to the central controller  36 . This communication may be by a variety of methods, including wireless Ethernet, radio transmission, or other wireless method. The central controller  36  receives the wireless signal and records the logical position of the divert device  34  according to the methods described above. After the loop conveyor  22  completes one cycle, the logical positions of the divert locations  32  will have been determined Additional cycles may be used to confirm or verify the logical positions of the divert locations  32 . 
     In the preferred method, the configuration sorter tray  38  is provided with index #0 at the load station  30  and the remaining carrier trays are provided with an index between #1 and #29, although the index range may vary depending on the number of carriers  24  provided. The loop conveyor  22  completes at least one cycle and as each index feature  28  is detected the controller  36  is notified by wireless communication and the index of the carrier  24  at the load station  30  is recorded. Once the cycle has finished and all of the divert locations  32  have been indexed, the configuration operation is complete. 
     In the above-described operation, the configuration sorter tray  38  is described as replacing one of the carriers  24 . However, it is also contemplated that the configuration sorter tray  38  may be removably attached to one of the existing carriers  24 , or one of the existing carriers may be permanently modified to include a sensor  28  and wireless I/O  44 . 
     During the sorting operation, the configuration sorter tray  38  may be removed from the loop conveyor  22  and replaced with a carrier  24 . Articles to be sorted are loaded into indexed carriers  24  at the load station  30 . Carriers  24  then proceed along the loop conveyor  22  through each of the divert locations  32 . When the carrier  24  containing the article to be sorted arrives at the predetermined divert location  32 , the divert device  34  is actuated by the central controller  36  to tilt or otherwise affect carrier  24  to direct the article to be sorted to the output. 
     During the sorting operation the first step is to determine the divert location for the article to be sorted. In this first step, the preferred divert location for the article to be sorted is communicated to the controller  36 . First, the article to be sorted must be identified, such as by manual or automatic scanning of all or part of a one- or two-dimensional barcode, reading an RFID chip, manual input, or other methods known and used in the art. A variety of methods are also contemplated for determining the preferred divert location based on the identity of the article to be sorted. In a preferred method, the article to be sorted includes a unique identifier corresponding to a specific package and destination. This number can be compared to a lookup table to determine the preferred divert location  32 . This destination is then communicated to the central controller  36 . One example of this lookup table is illustrated in the following sample Table 2: 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Article number 
                 Divert Location 
               
               
                   
                   
               
             
            
               
                   
                 #1026 
                 #1 
               
               
                   
                 #1380 
                 #3 
               
               
                   
                 #1507 
                 #4 
               
               
                   
                 #1931 
                 #2 
               
               
                   
                   
               
            
           
         
       
     
     This lookup table is provided to be an example. Other methods of determining the divert location are contemplated. Further, additional steps may be needed to correlate each article with a divert location. For example, each article to be sorted may be indexed to a destination and each destination may be indexed to a divert location. The relationship between the destination and the divert location, or even the article and destination, may change periodically. 
     In a second step, the central controller  36  constructs a table between various carrier indices and their preferred divert locations  32 , such as illustrated in the following sample Table 3: 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Carrier Index 
                 Divert Location 
               
               
                   
                   
               
             
            
               
                   
                 #1 
                 #1 
               
               
                   
                 #2 
                 #3 
               
               
                   
                 #3 
                 #4 
               
               
                   
                 #4 
                 #2 
               
               
                   
                   
               
            
           
         
       
     
     In a third step, the controller  36  compares the carrier/divert table (Table 3) with the load station/divert index (Table 1) to determine which diverters to activate when each indexed carrier  24  is located at the load station  30 , or other reference point. Combining these two tables yields the following sample Table 4 that provides which divert device(s)  34  should be activated when each indexed carrier  24  is at the load station  30 : 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 Load Station Index 
                 Divert Location 
               
               
                   
                   
               
             
            
               
                   
                 11 
                 1 
               
               
                   
                 19 
                 2 
               
               
                   
                 20 
                 3 
               
               
                   
                 28 
                 4 
               
               
                   
                   
               
            
           
         
       
     
     As will be appreciated, as more carriers  24  are filled and with more divert locations  32 , multiple divert devices  34  may need to be activated when a single carrier is located at the load station  30 . 
     Finally, during the sorting operation, as each indexed carrier arrives at the reference point (e.g. load station  30 ), the controller  36  will search the load station/divert table to determine which divert locations  32  should be activated and activate the assigned divert devices  34 . 
     The above described method utilizing lookup tables and indexed discrete carriers  24  is an example version of the sorting operation. As previously described, various types of indices, carriers, and methods of determining the logical position of the divert locations  30  are contemplated, either including or omitting the above-described lookup tables. Further, various methods for diverting items are contemplated. The sorting operation may be adapted to admit variations in the configuration operation. 
     While the configuration and sorting operations are described as separate, it is contemplated that the two operations may be performed concurrently. According to one embodiment, sensor  28  may be permanently affixed to the loop conveyor  22  for continuously monitoring the logical positions of the divert devices  34  and continuously updating the central controller  36  with these logical positions. This allows the system to adapt to small or large changes in the arrangement of the divert locations, either intentional or accidental; alert operators to changes in the configuration; and provide a low-cost continuous diagnostic and maintenance system. 
     While certain embodiments have been described, it must be understood that various changes may be made and equivalents may be substituted without departing from the spirit or scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its spirit or scope.