Abstract:
A method of operating a cross belt slat sorter includes moving a first item of a first type positioned on the sorter. A database is maintained that stores transport requirements for different item types. A control system ascertains a first type of the first item via a separate vision system that is operatively connected to the control system. The database is accessed to establish the first transport requirements for the first item based on the first type. Belts are controlled based on the first transport requirements of the first item. A second item is moved on the belts, and a second type of the second item is observed with the vision system. The database is accessed to ascertain second transport requirements for the second item. The belts are controlled based on the second transport requirements of the second item.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 14/304,010 filed Jun. 13, 2014, which is herein incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     A large number of modern material handling systems are designed to handle one type of package or item efficiently but lack the flexibility to handle a wide variety of items that are sized and/or shaped differently. Typically, such systems include mechanical guides for orienting or locating items which can be problematic when dealing with differently sized, weighted, and/or shaped items. Furthermore, such systems have fixed locations where items can be induced/charged or discharged from the conveyor and the speed as well as angle of items being discharged from the conveyor is fixed. For example, slat type sorters have been used that incorporate shoes for discharging items from the conveyor. However, the shoes are mechanically guided which in turn fixes or limits induction and discharge locations, and the speed of the shoes for discharging items is limited to the travel speed of the conveyor. As another example, cross belt sorters have been proposed in which a mechanical follower converts the relative movement of the conveyor into mechanical motion that moves the belts. In this type of cross belt sorter, the speed of the belts for discharging items is limited by the overall speed of the conveyor. Moreover, the mechanical linkages required to drive the belt force the system to have fixed locations where items can be induced onto or discharged from the conveyor. As might be appreciated, this inflexibility can be further problematic for items that require special handling, such as oversized or delicate items. 
     Other cross belt sorter systems have been proposed that incorporate electric motors to drive relatively wide belts that are 12 inches wide or even larger. Typically, the belts are sized to accommodate a single item. The belts have to be wide enough so that one item is able to be comfortably located on the belt and not interfere with items on adjacent belts. The systems likewise provide limited flexibility because they still require mechanical guides or other structures for orienting and positioning the items on the individual belt. Due to the large width of the belts along with the space required for the electric motor and associated control systems, recirculation of the belts is limited to a horizontal loop which among other things tends to waste floor space and limit its operational value. For example, the gap between adjacent carriages or carts needs to be sufficiently large so as to accommodate the turn radius of the conveyor. This gapping between carriages reduces the density of items on the conveyor which in turn reduces throughput. The gapping also inhibits the placement of items. Thus, there is a need for improvement in this field. 
     SUMMARY 
     A cross belt slat sorter system has been developed to perform like a shoe sorter type system with additional advantages. Relative to traditional cross belt sorters, the cross belt slat sorter system described herein has relatively thin belts (i.e., having a width similar to slats) that are independently operated via electric motors. This allows packages or other items/stock keeping units (SKUs) to be loaded onto a single belt or across multiple belts. The width of a belt for an individual unit is typically between about 6 inches (15.24 cm) to about 8 inches (20.32 cm). In another variation, the width of the belt is 4 inches (10.16 cm) to 8 inches (20.32 cm) wide. In a further example, the belt width is 7 inches (17.78 cm) or less, and in another example, the belt width is 6.5 inches (16.51 cm). In still yet another example, the belt width is 4 inches (10.16 cm) to 5 inches (12.70 cm) wide. Additionally, for longer sorters with low throughput speeds, one or more filler slats can be positioned between groups of cross belt slat assemblies (used for the “gap” between products). The filler slat can be used to space apart groups of cross belt units. A filler slat does not include a belt or any other motorized equipment. Due to the larger belts, traditional cross-belt sorter systems recirculate the belt carriages in a horizontal loop. Given the relatively thin width of the belts in the system described herein, cross belt slat carriages can be recirculated using not only a horizontal recirculation loop but also via a vertical recirculation loop. Having the ability to recirculate vertically, among other things, reduces the overall footprint occupied by the cross belt slat sorter conveyor system. 
     Given the individual belts are independently controllable, the belts are able to operate at different speeds and/or different directions so as to give greater flexibility in sorting the products. The individual belts are for instance programmable with respect to direction, acceleration, deceleration, terminal velocity, and/or length of time. For example, when a product is loaded across multiple belts, its position on the conveyor can be readjusted (e.g., rotated, centered, left or right aligned) by having the adjacent belts move in the same or opposite directions. A vision system at the sorter induction can be used to identify the orientation of the product on the conveyor, and if needed, the appropriate cross belts can be actuated to reposition, or pre-align, the product on the conveyor. This eliminates the need for additional mechanical devices to orient packages or other items on the conveyor belt. 
     In traditional shoe sorter systems, the speed of the cross belt is limited by the speed of the overall conveyor because mechanical interfaces (e.g., guides, channels, with electro or pneumatic switches) are used to drive the belts. On the other hand, the electric motors in the current system allow belts to operate at a speed independent of the traveling speed of the overall conveyor belt. This allows products to be diverted off the sorter at different angles (e.g., at 30°, 45°, or 90° angles) by changing the speed and sequence of the cross belt(s). In addition, different types of products, such as fragile items, items having a high center of gravity, etc., can be handled differently by being diverting at different speeds, accelerations, and/or angles. The system also allows greater flexibility in locating where products are merged and diverted from the sorter because it does not rely on mechanical interfaces for designating merge/divert locations. Instead, the individual locations can be configured by a simple software change. SKUs can be loaded inducted/merged and unloaded diverted/sorted from both sides of the sorter as well. 
     The system further includes plug and play cross belt assemblies or carriages that are modular and easily replaceable such that a non-operating cross belt slat assembly can be easily replaced with a new cross belt assembly to thereby shorten overall downtime for the cross belt slat sorter. The individual cross belt assemblies are controlled via wireless communication. In one example, a single wireless transmitter provides communications to all of the carriages. In one particular form, the system includes two communication subsystems that receive information from a remote control system via a wireless connection. In another example, data for controlling the individual cross belt assemblies is transmitted through an inductive communication rail. In one specific example, the conveyor includes a pair of controllers wherein a single controller is mounted on each of the two opposing sides of a single cross belt assembly for wireless communication. The cross belt slat assemblies in this example are also individually self-powered with a 24 volt DC motor. The slats are networked together for both power and communications. Therefore, one power supply bus can power all cross belt slats and one wireless receiver can provide communications to all cross belt slats. 
     Aspect 1 concerns a sortation system that includes a frame and two or more carriages riding along the frame in a travel direction. Each carriage includes a belt and an electric motor. The belt is oriented at a direction that is transverse to the travel direction of the carriage. The electric motor is configured to drive the belt. The cross belt has a width that is at most 8 inches (20.32 cm) wide. 
     Aspect 2 concerns the sortation system of Aspect 1, wherein the carriages have a vertical recirculation pattern along the frame. 
     Aspect 3 concerns a sortation system that includes a frame and two or more carriages riding along the frame in a travel direction. Each carriage includes a belt oriented at a direction that is transverse to the travel direction of the carriage and an electric motor configured to drive the belt. The carriages have a vertical recirculation pattern along the frame. 
     Aspect 4 concerns the sortation system of any preceding aspect, wherein the belt has a width that is at most 7 inches (17.78 cm) wide. 
     Aspect 5 concerns the sortation system of any preceding aspect, wherein the belt has a width that is at least 3.5 inches (8.89 cm) wide. 
     Aspect 6 concerns the sortation system of any preceding aspect, wherein a gap between the belts of adjacent carriages is at most 1 inch (2.54 cm). 
     Aspect 7 concerns the sortation system of any preceding aspect, wherein the electric motors on each of the carriages are configured to operate independently of one another. 
     Aspect 8 concerns the sortation system of any preceding aspect, wherein each carriage includes a controller operatively coupled to the electric motor to control movement of the belt. A wireless subsystem is operatively coupled to the controller on each carriage. 
     Aspect 9 concerns the sortation system of any preceding aspect, further including a first wireless subsystem networked with controllers for a first zone of carriages and a second wireless subsystem networked with controllers for a second zone of carriages. The first and second wireless subsystems are positioned so that at least one of the wireless subsystems is able to receive a wireless signal from a wireless transmitter. 
     Aspect 10 concerns the sortation system of Aspect 9, wherein the first and second wireless subsystems are positioned on opposite sides of a loop of the carriages to maintain wireless communication. 
     Aspect 11 concerns the sortation system of any preceding aspect, further including a power rail configured to supply power to the carriages. Each carriage includes a power coupling positioned proximal to the power rail to receive power from the power rail. 
     Aspect 12 concerns the sortation system of any preceding aspect, further including a power rail positioned along the frame to provide power to the carriages. At least one of the carriages includes a gateway configured to receive data for controlling the carriages from the power bar. 
     Aspect 13 concerns the sortation system of any preceding aspect, further including a vision system positioned to view an item disposed on two or more of the carriages. The vision system is configured to align the item by at least moving the belt on one of the carriages relative to the belt on the other carriage. 
     Aspect 14 concerns the sortation system of any preceding aspect, further including one or more slats positioned between adjacent carriages. 
     Aspect 15 concerns the conveyor sortation system of any preceding aspect, wherein each of the carriages have an overall height that is at most 5 inches (12.70 cm) 
     Aspect 16 concerns a method of operating the conveyor sortation system of any preceding aspect. 
     Aspect 17 concerns a method. An item positioned on two or more belts is moved in a travel direction of a conveyor. The belts extend at a direction that is transverse to the travel direction of the conveyor. A control system of the conveyor determines the orientation of the item is incorrect. In response, the item is reoriented to a correct orientation by moving the belts relative to one another. 
     Aspect 18 concerns the method of any one of aspects 16-17, wherein the orientation is determined by observing the item with a vision system that is operatively connected to the control system. 
     Aspect 19 concerns the method of any one of aspects 16-18, wherein the reorienting occurs by moving the belts in different directions. 
     Aspect 20 concerns the method of any one of aspects 16-19, wherein the reorienting occurs by moving the belts at different speeds. 
     Aspect 21 concerns the method of any one of aspects 16-20. A type of the item positioned on the two or more belts is ascertained. Transport requirements for the item are determined based on the type. The belts are controlled based on the transport requirements of the item. 
     Aspect 22 concerns a method. An item positioned on one or more belts is moved in a travel direction of a conveyor. The belts extend at a direction that is transverse to the travel direction of the conveyor. A type of the item positioned on the belts is ascertained with a control system for the conveyor. One or more transport requirements for the item based on the type are established with a control system. The belts are controlled based on the transport requirements of the item. 
     Aspect 23 concerns the method of any one of aspects 21-22, wherein controlling of the belts includes diverting the item at a divert angle based on the transport requirements. 
     Aspect 24 concerns the method of any one of aspects 21-23, wherein controlling of the belts includes diverting the item at a divert speed based on the transport requirements. 
     Aspect 25 concerns the method of any one of aspects 21-24, wherein the item is a first item, the type is a first type, and the transport requirements are first transport requirements. A second item is moved on the cross belts. A second type of the second item is ascertained that is different from the first type for the first item. One or more second transport requirements are established for the second item based on the second type. The cross belts are controlled based on the second transport requirements of the second item in which the second transport requirements are different from the first transport requirements of the first item. 
     Aspect 26 concerns the method of any one of aspects 21-25, wherein said controlling includes controlling two or more of the cross belts upon which the item is positioned. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a cross belt slat sorter system. 
         FIG. 2  is a diagrammatic view of a communication system for the  FIG. 1  sortation system. 
         FIG. 3  is a side view showing vertical recirculation of carriages in the  FIG. 1  sortation system. 
         FIG. 4  is a diagrammatic view of a wireless communication system for the  FIG. 1  sortation system. 
         FIG. 5  is a diagrammatic view of another example of a communication system used in the  FIG. 1  sortation system. 
         FIG. 6  is a diagrammatic view of a wired communication system for the  FIG. 1  sortation system. 
         FIG. 7  is a partial perspective view of a frame used in the  FIG. 1  sortation system. 
         FIG. 8  is a perspective view of a belt of carriages used in the  FIG. 1  sortation system. 
         FIG. 9  is a top view of the carriages in the  FIG. 8  belt. 
         FIG. 10  is a rear perspective view of one of the carriages. 
         FIG. 11  is a rear perspective view of a gateway carriage used in the  FIG. 1  sortation system. 
         FIG. 12  is a front perspective view of the  FIG. 11  gateway carriage. 
         FIG. 13  is a perspective view of a power carriage used in the  FIG. 1  sortation system. 
         FIG. 14  is a side view of the  FIG. 13  power carriage. 
         FIG. 15  is a front view of a client carriage used in the  FIG. 1  sortation system. 
         FIG. 16  is a perspective view of a support carriage. 
         FIG. 17  is a bottom view of the  FIG. 16  support carriage. 
         FIG. 18  is a top view of the conveyor system that incorporates slats spacing apart the carriages. 
         FIG. 19  is a flow diagram illustrating a technique for reorienting items in the  FIG. 1  sortation system. 
         FIG. 20  shows a top view of a belt with an item to be reoriented. 
         FIG. 21  shows a top view of the belt with the item in  FIG. 20  reoriented. 
         FIG. 22  is a flow diagram illustrating a technique for controlling the carriages in the  FIG. 1  sortation system. 
         FIG. 23  is a top view of items being transported in accordance with the technique described with respect to the flow diagram in  FIG. 22 . 
     
    
    
     DETAILED DESCRIPTION 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended. Any alterations and further modifications in the described embodiments, and any further applications of the principles of the invention as described herein are contemplated as would normally occur to one skilled in the art to which the invention relates. One embodiment of the invention is shown in great detail, although it will be apparent to those skilled in the relevant art that some features that are not relevant to the present invention may not be shown for the sake of clarity. 
     The reference numerals in the following description have been organized to aid the reader in quickly identifying the drawings where various components are first shown. In particular, the drawing in which an element first appears is typically indicated by the left-most digit(s) in the corresponding reference number. For example, an element identified by a “ 100 ” series reference numeral will likely first appear in  FIG. 1 , an element identified by a “ 200 ” series reference numeral will likely first appear in  FIG. 2 , and so on. 
     A perspective view of a cross belt slat sorter system  100  is illustrated in  FIG. 1 . As shown, the system  100  includes a cross belt slat conveyor  102 , an induction or loading conveyor  104 , and discharge or unloading conveyor  106 . The conveyor  102  includes a belt or loop  108  of cross belt slat carriages or carts  110  that ride along a frame  112 . The belt  108  is driven by a drive motor  114 . As will be explained in greater detail below, the carriages  110  are designed so as to promote vertical recirculation of the carriages  110 . Having the ability to recirculate vertically allows the conveyor  102  to have a more compact footprint as well as provides greater operational flexibility. Each carriage  110  includes a cross belt  116  that extends transverse to a travel direction  118  of the belt  108 , and in the depicted embodiment, the cross belt  116  extends perpendicular to the travel direction  118 . The cross belts  116  on the carriages  110  are independently operable relative to one another such that the cross belts  116  are able to be driven in different directions and at varying speeds. This provides greater flexibility for design layouts as well as operational efficiencies. 
     A block diagram of one example of a communication system  200  used for operating the conveyor system  100  is depicted in  FIG. 2 . As mentioned before, the conveyor  102  includes a belt  108  with a series of carriages  110 , and the belt  108  rides along the frame  112 . There are a number of different types of carriages  110  in the system  100 . For example, as shown, the carriages  110  include a gateway carriage  202 , a power carriage  204 , and a client or standard carriage  206 . The gateway carriage  202  is configured to wirelessly communicate with a control system  208  via a wireless transceiver  210 . In one example, the control system  208  is in the form of a programmable logic controller (PLC), but the control system  208  can be configured differently in other examples. The control system  208  through the gateway carriage  202  is configured to relay commands for controlling the carriages  110  as well as receive information about the operations of the carriages  110 . In the illustrated example, the control system  208  further includes a vision system  212  and sensors  214  that are used to sense items in the conveyor system  100  as well as other operational parameters. For instance, the sensors  214  can include proximity sensors/switches, light curtains, thermal sensors, barcode readers, etc. Each carriage  110  includes a controller  216  that controls a motor  218 . The power carriage  204  provides power to one or more of the other carriages  110  on the belt  108 . 
     Each carriage  110  includes a controller  216  and a motor  218  that are operatively connected together so as to communicate with one another. The motor  218  is used to move the cross belt  116 , and the controller  216  via the motor  218  controls the speed and/or direction of the cross belt  116  on the carriage  110 . In one example, the motor  218  is an electric motor, and the controller  216  communicates with the motor  218  via a wired connection. It however should be appreciated that the motor  218  and controller  216  can communicate in other manners such as through a fiber-optic connection and/or a wireless connection. As can be seen, the client carriage  206  includes the controller  216  and motor  218 . In addition to the controller  216  and motor  218 , the gateway carriage  202  includes a wireless subsystem  220  that communicates wirelessly with the wireless transceiver  210  of the control system  208 . The wireless subsystem  220  in turn communicates with the controller  216  of the individual carriages  110  via a communication path  222 . In one example, the wireless subsystem  220  includes a gateway that connects over a cable to an Ethernet radio that provides a wireless connection, but the wireless subsystem  220  can be configured differently in other embodiments. In one form, the communication path  222  includes an electrically conductive wired bus that is operatively connected to the controller  216  of the carriages  110 , but it should be recognized that the wireless subsystem  220  can be operatively connected to the controller  216  in other manners, such as via fiber optic cables. The gateway carriage  202  can be configured to provide control commands from the control system  208  to all or part of the carriages  110  on the belt  108 . In the illustrated example, the gateway carriage  202  is operatively connected via the communication path to a group of carriages  110  to form a zone  223 , and the belt  108  of carriages  110  includes multiple zones  223  each having their own wireless subsystem  220 . In another example, the gateway carriage  202  is operatively connected via the communication path to all of the carriages  110  on the belt  108 . 
     As can be seen in  FIG. 2 , the power carriage  204 , in addition to the controller  216  and motor  218 , further includes a power coupling  224  that is used to power the carriages  110  on the belt  108 . The power coupling  224  receives power through a power rail  226  located on the frame  112 . In one form, the power coupling  224  directly contacts the rail  226  so as to receive electrical energy from the rail  226 . In another form, the power coupling  224  inductively receives power from the power rail  226 . It should be recognized that the carriages  110  can be powered in other manners, such as through batteries and/or solar cells, to name just a few examples. 
     As alluded to before, the design of the conveyor system  100  allows the carriages  110  with electrical motors  218  to be recirculated vertically which in turn can reduce the floor space the system occupies.  FIG. 3  shows a diagram of this vertical recirculation of the carriages  110  in the conveyor system  100 . As shown, the carriages  110  form the loop  108  in which the carriages  110  are recirculated below the carriages  110  that can be used to move items. In warehouse and manufacturing environments, wireless interference can be a significant concern. This interference issue can be pronounced with systems utilizing vertical recirculation of the carriages  110  because the drive motor  114 , the motors  218  for the belts  116 , and other electrical components can interfere with receipt of the wireless signal by the gateway carriages  202 . In typical cross belt sorter systems, the cross belts are recirculated horizontally, that is, in the same horizontal plane. As a result, the cross belts are less susceptible to interference because they usually have a clear line of sight to any wireless antenna. Other systems utilize mechanical interfaces to drive the cross belts which in turn can reduce some electrical interference. However, as noted before, such mechanical systems provide very limited flexibility as to the speed of the cross belts and where items can be induced and discharged from the cross belts. To address this, the gateway carriage  202  in some examples can control a subset of the carriages  110  on the belt  108  to form zones  223 . By doing so, the risk of interference can be reduced. For instance, as is depicted in  FIG. 4 , the belt  108  includes two gateway carriages  202  with two zones  223 . The gateway carriages  202  are positioned on opposite sides of the belt  108  so that at least one of the gateway carriages  202  has a clear wireless signal with the transceiver  210  of the control system  208 . In particular, one of the gateway carriages  202  is positioned on a top side  402  of the belt  108  where items are loaded and unloaded, and the other gateway carriage  202  is positioned on a bottom side  404  of the belt  108  where the carriages  110  are recirculating and are typically shielded by the frame  112 . In other forms, the belt  108  can include more than two gateway carriages  202  and zones  223 . For instance,  FIG. 5  shows an example where the belt  108  includes three gateway carriages  202  and corresponding zones  223 . This configuration shown in  FIG. 5  ensures that at least one of the gateway carriages  202  is within range of the wireless transceiver  210 . It should be recognized that in other examples where the wireless transceiver  210  is located elsewhere, such as closer to the bottom side  404  of the belt  108 , other configurations could be used for locating the gateway carriages  202  closer to the transceiver  210 . 
     In other variations, the control system  208  can communicate with the carriages  110  via a wired connection.  FIG. 6  shows a diagrammatic view of a communication system  600  that uses a wired connection between the control system  208  and the carriages  110  on the belt  108 . As should be recognized, the system  600  includes a number of components in common with the communication system  200  described with reference to  FIG. 2 . For instance, the carriages  110  in the communication system  600  include a controller  216  and a motor  218 . The communication system  600  further includes the frame  112  with the power rail  226  and client carriages  206 . For the sake of brevity and clarity, these common components will not be discussed in detail below, but please refer to the previous discussion of these components. Instead of using wireless communication, the belt  108  of carriages  110  includes one or more gateway carriages  602  with a wired gateway  604 . The wired gateway  604  is operatively connected to the power coupling  224 . The power coupling  224  not only supplies power to the carriage, but the power coupling  224  provides a communication pathway for the control system  208 . Specifically, the control system  208  is operatively coupled to the power rail  226  via a communication pathway  606 . The current used to power the carriages  110  is encoded with a signal that is transmitted to the wired gateway  604  via the power coupling  224 . As mentioned above, the power coupling  224  can directly receive the signal from the power rail  226  through direct contact and/or indirectly through induction. The wired gateway  604  in turn communicates with the controllers  216  of the carriages  110  via the communication path  222 . It should be recognized that the conveyor system  100  can have different communication configurations in other embodiments. 
       FIG. 7  shows a partial perspective view of the frame  112  with the belt  108  removed. As can be seen, the frame  112  includes one or more drive chains  702 , guide rails  704 , and recirculation gear assemblies  706 . The drive motor  114  ( FIG. 1 ) via the drive chains  702  is configured to move the belt  108  in the travel direction  118 . The guide rails  704  are configured to guide the carriages  110 . The drive chain  702  loops around the recirculation gear  706  so as to vertically recirculate the carriages  110  on the belt  108  ( FIG. 1 ). The drive chains  702  each include a series of carriage engagement structures  708  which in the illustrated embodiment are in the form of pins. The pins  708  connect the carriages  110  to the drive chain  702  and further facilitate pivoting of the carriages  110  as they recirculate around the belt  108 . 
       FIG. 8  illustrates a perspective view of the belt  108  of carriages  110 . Opposite the cross belt  116 , each carriage  110  includes a conveyance portion  802  where the carriage  110  is coupled to the frame  112 .  FIG. 9  shows a top view of the carriages  110  in the belt  108 . The carriages  110  have a width that generally corresponds to that of a slat typically found on conveyors. As shown, the cross belt  116  of the carriage  110  has a width  902  that is generally narrow so as to correspond to a width of a slat. With the narrow width  902  of the cross belt  116 , items are typically loaded onto more than one of the cross belts  116  which in turn gives the system  100  the ability to reorient items on the cross belts  116 . Moreover, by having such a narrow width  902 , the carriages  110  are able to be recirculated vertically. As mentioned before, typical cross belt conveyors recirculate the individual cross belts using a horizontal recirculation loop. Having such wide cross belts makes it difficult, if not practically impossible, to recirculate the carriages  110  vertically. In one example, the width  902  of the cross belt  116  is at most 8 inches (20.32 cm), and in other examples, the width  902  is at most 7 inches (17.78 cm). In still yet other examples, the width  902  of the cross belt  116  is at least 6 inches (15.24 cm) wide. In a further example, the width  902  of the cross belt  116  is at least 4 inches (10.16 cm) wide, and in other examples, the width  902  of the cross belt  116  is at least 3.5 inches (8.89 cm) wide. In one form, the width  902  of the cross belt  116  is 6 to 8 inches (15.24 to 20.32 cm), and in one particular form, the width  902  of the cross belt  116  is 6.5 inches (16.51 cm). In one form, the width  902  of the cross belt  116  is 4 to 5 inches (10.16 to 12.70 cm). In one example, the cross belts  116  on adjacent carriages  110  are closely spaced together such that a gap  904  between the adjacent cross belts  116  is minimal so as to promote contact with items on the cross belts  116 . In one particular example, the gap  904  is at most 1 inch (2.54 cm) wide. However, the gap  904  between adjacent cross belts  116  in other examples can be wider (or thinner). As will be discussed below, the cross belt  108  in other examples includes filler slats that widely space apart the cross belts  116  for larger items and/or in low throughput situations. 
       FIG. 10  shows a rear perspective view of one of the carriages  110 . The external features shown in  FIG. 10  are generally common to all the types of carriages discussed before (i.e., gateway  202 , power  204 , and client  206  carriages). As shown, the carriage  110  includes the belt  116  for inducing, transporting, and discharging items from one or more of the carriages  110 . The carriage  110  further includes a housing  1002  for protecting internal components of the carriage  110 . The conveyance portion  802  facilitates movement of the carriage  110  along the frame  112 . As illustrated, the conveyance portion  802  of the carriage  110  includes one or more guide rollers  1004  that are configured to ride along the guide rail  704  ( FIG. 7 ) of the frame  112 . The carriage  110  at the conveyance portion  802  further includes a drive chain engagement structure  1006  that is configured to secure the carriage  110  to the drive chain  702 . As can be seen, the drive chain engagement structure  1006  in the illustrated example is located between a pair of the guide rollers  1004  on each side of the carriage  110 . The drive chain engagement structure  1006  is in the form of a protrusion with a pin receiving cavity  1008  in which the pin  708  of the drive chain  702  is received. It should be recognized with this construction that the carriages  110  can be easily removed and replaced such as during routine maintenance or when one of the carriages  110  fail. Moreover, the drive chain engagement structure  1006  allows the carriage  110  to be easily recirculated vertically within the system  100 . 
     As will be described in further detail below, the carriage  110  has been designed to minimize its overall height. Among other things, by minimizing the overall height, the overall profile of the system  100  can be reduced which in turn allows the system  100  to operate in a manner more similar to conventional slat sorters. As a result, the system  100  can be more readily substituted for conventional slat sorters as well as for other uses. In addition, the lower profile of the carriage  110  helps to facilitate recirculation of the carriages. In one example, height  1010  of the carriage  110 , which is measured from the center of the pin receiving cavity  1008  to the top of the cross belt  116 , is at most 5 inches (12.70 cm). In one particular example, the height  1010  of the carriage  110  is equal to or less than 4.67 inches (11.85 cm). In the illustrated embodiment, almost all of the components of the carriage  110  are located above the drive chain engagement structure  1006  (i.e., at or above the cart engagement pins  708  and below the top surface of the cross belt  116 ), but in other variations, some of the components of the carriage  110  can hang below the drive chain engagement structure  1006 . 
       FIGS. 11 and 12  respectively show rear and front perspective views of the gateway carriage  202  with the housing  1002  removed so that the internal components of the gateway carriage  202  can be readily viewed. Unless noted and/or illustrated otherwise, it should be appreciated that the internal components, such as for the cross belt drive train, are common to all types of carriages (e.g., gateway  202 , power  204 , and client  206  carriages) As noted before, the gateway carriage  202  includes the controller  216 , motor  218 , and a wireless subsystem  220  along with the guide roller  1004  and the drive chain engagement structure  1006  with the pin receiving cavity  1008 . To support items placed against the cross belt  116 , the gateway carriage  202  includes a support plate  1102 . Guide rollers  1104  are disposed at opposite ends of the support plate  1102  so as to guide the cross belt  116 . Belt tensioning rollers  1106  are disposed on opposite sides of a drive roller  1108  which is driven by the motor  218 . The belt tensioning rollers  1106  are configured to maintain tension on the cross belt  116  over time so that the cross belt  116  does not become slackened and potentially damaged. In addition, the belt tensioning rollers  1106  reduce the risk of slippage of the belt  116  against the drive roller  1108 . Looking at  FIG. 12 , the motor  218  is connected to a drive pulley assembly  1202  that includes a drive belt  1204  that drives the drive roller  1108 . As should be recognized, this construction helps to simplify maintenance as well as provides a compact design which makes it suitable for vertical recirculation. Moreover, a single motor  218  is able to drive the entire cross belt  116 . In addition, this design allows the cross belt  116  to be easily replaced when worn or broken. 
       FIGS. 13 and 14  respectively show perspective and side views of the power carriage  204 . It should be recognized that the power carriage  204  shares a number of features in common with the previously discussed carriages  110 . The power coupling  224  on the power carriage  204  in the illustrated example includes a pair of coupling arms  1302  disposed on opposing sides of the power carriage  204 . At the end of each coupling arm  1302 , the power coupling  224  has contacts  1304  configured to electrically connect to the power rail  226  of the frame  112  ( FIG. 2 ). The coupling arms  1302  are pivotally coupled to an adapter  1306  that is connected to the power carriage  204 . Turning to  FIG. 14 , one or more springs  1402  are connected to the contact  1304  so as to bias the coupling arms  1302  to make electrical contact with the power rail  226 . 
       FIG. 15  shows a front view of the client carriage  206  with the housing  1002  removed. The client carriage  206  has the same components as the gateway carriage  202 , with the exception that the client carriage  206  does not include the wireless subsystem  220 . For instance, as shown, the client carriage  206  includes the belt  116 , controller  216 , and motor  218  as well as the other structural components discussed previously. 
     In certain situations, the cross belt  116  does not need to extend for the full width of the carriage  110 . A support carriage  1600  shown in  FIGS. 16 and 17  has one or more cross belts  1602  that do not cover the entire or nearly the entire width of the support carriage  1600 .  FIG. 16  shows a perspective view of the support carriage  1600 , and  FIG. 17  shows a bottom view of the support carriage  1600 . In the illustrated example, the motor and gearbox are situated inside the overall belt so as to reduce the overall height of the carriage  1600 . As shown, the cross belt  1602  is stretched between a drive roller  1604  and a guide roller  1606 . Between the rollers  1604 ,  1606 , the support carriage  1600  has one or more support plates  1608 . The support plate  1608  can provide additional support for items on the carriage  1600  without unduly burdening the cross belt  1602 . The support plates  1608  can be especially helpful for large or bulky items. Normally, the support carriage  1600  has cross belts  1602  located on opposite sides of the carriage  1600 . However, in the illustrated example, one of the cross belts  1602  have been removed from the drive  1604  and guide  1606  rollers so as to better show guide grooves  1610  in the rollers  1604 ,  1606 . The guide grooves  1610  help to center and/or orient the cross belts  1602  on the support carriage  1600 . In other examples, the support carriage  1600  can include one or even more than two cross belts  1602 . 
     The carriages  110  can be used in conjunction with other types of conveyor systems.  FIG. 18  illustrates one example of a conveyor system  1800  that incorporates other types of conveyor components. As depicted, the carriages  110  can be spaced apart by slats  1802  that do not include cross belts  116  such that the entire belt  108  does not need to be formed from the carriages  110  with the cross belts  116 . The slats  1802  can act like spacers and be used to space apart the carriages  110 , for instance in low throughput situations where carriages  110  can be grouped together so as to match the required throughput. In other examples, the slats  1802  can provide additional support for heavy and/or bulky items, such as refrigerators, televisions, etc. as shown by dashed line  1804  in  FIG. 18 . Items  1804  can span across the carriages  110  and are supported by one or more of the slats  1802  in between. The slats  1802  can have low frictional resistance (i.e., be slippery) so as to facilitate sliding of the item  1804  across the slats  1802  during induction or discharge of the item  1804 . 
     The greater control and flexibility provided by the conveyor system  100  allows the system  100  to eliminate a number of unnecessary components. For instance, typical conveyor systems include chutes and other types of structures for locating items on the conveyor such that the items are properly oriented for subsequent activities (e.g., barcode scanning, discharge, assembly, label application, package closure, etc.). However, these additional guide structures add expense as well as create maintenance and operational issues. For example, boxes can become jammed in the guiding structures of the conveyor system, and the repeated pounding experienced by the guiding structures can lead to premature failure. The conveyor system  100  described above eliminates the need for additional guiding structures because the belts  116  on each carriage  110  are independently operable such that they can move at different speeds and in different directions. With this ability to operate independently, the carriages  110  are able to reorient items on the belt  116  without the need of additional mechanisms. 
     A technique for reorienting items on the conveyor belt  108  without the need of external inputs will be initially described with reference to a flowchart  1900  illustrated in  FIG. 19 .  FIGS. 20 and 21  show top views of the belt  108  as an example of when an item is being reoriented according to this technique. The acts or stages for this technique will be described as being performed by the control system  208  and the vision system  212  (see e.g.,  FIGS. 2 and 6 ), but it should be recognized that all or part of these acts can be performed, solely or partially, by other components, such as via the sensors  214 , controllers  216 , wireless subsystem  220 , wired gateway  604 , and/or external computer systems, to name just a few examples. In stage  1902 , the control system  208  via the vision system  212  determines the orientation and/or location of the item  1804  on the carriages  110  as the belt  108  moves in the travel direction  118 . As can be seen, the item  1804  spans across the belts  116  of two or more carriages  110  as the item  1804  travels in the travel direction  118 . The control system  208  in stage  1904  determines whether or not the item  1804  is oriented and/or positioned properly on the belt  108 . In the example illustrated in  FIG. 20 , the item  1804  is slightly rotated and located off-center on the belt  108 . It should be recognized that the item  1804  can be improperly oriented in other ways. For instance, the item  1804  could be laterally offset to one side. It should be noted that while the item  1804  in the drawings has a rectangular or boxed shape, the items in other examples can have different shapes, such as irregular shapes, circular shapes, etc. If in stage  1904  the control system  208  determines that the item  1804  is properly oriented, the control system  208  via the vision system  212  then determines the orientation of the next item  1804  on the belt  108  in stage  1902 . Different types of items in stage  1904  may require different orientations and/or locations on the belt  108 . This technique can account for these variations in orientation requirements of the items  1804 . For instance, large items  1804  may be considered properly located when positioned on the center of the belt  108 , but smaller items  1804  may be considered properly located closer to the edges of the carriages  110 . 
     If the control system  208  in stage  1904  determines that the item  1804  is improperly oriented, the control system  208  proceeds to stage  1906  where the control system  208  uses the carriages  110  to reorient the item  1804 . For example, looking back at  FIG. 2 , the control system  208  via the wireless transceiver  210  sends one or more instruction signals to the appropriate wireless subsystem  220  of the gateway carriage  202 . The wireless subsystem  220  in turn transmits the instructions to the controllers  216  of the appropriate carriages  110 . Among other things, the instructions identify the one or more carriages  110  that need to be activated in order to reorient the item  1804  as well as the speed and direction the motor(s)  218  should operate in order to drive the belt  116  at the appropriate speed and direction. As symbolized by the length and direction of the cross belt motion arrows  2002  in  FIG. 20 , the speed and direction of the belt  116  on the carriages  110  on which the item  1804  rests are different. In the illustrated example, the carriages  110  are used to rotate the item  1804  clockwise so as to properly align it on the belt  108 . In particular, the belts  116  on one side of the item  1804  are moved in one direction and the belts  116  on the carriages  110  on the opposite side of the item move in the opposite direction so as to cause the clockwise motion of the item  1804 . Again, it should be appreciated that the belts  116  can be moved differently to reorient differently oriented items  1804  in other examples. For instance, a single belt  116  on a single carriage  110  can be used to reposition or reorient the item  1804  in other ways. Looking at  FIG. 21 , the vision system  212  can be used to confirm that the item  1804  is properly positioned before proceeding back to stage  1902 . 
     As mentioned before, having the motors  218  independently operate the cross belts  116  on the carriages  110  gives the conveyor system  100  greater flexibility in handling different items. Moreover, in contrast to systems with mechanical stops or controls, the conveyor system  100  is able to be quickly adapted to different operational needs. Changes can be made on the fly simply through software changes. For example, a location that was originally programmed to be a discharge location can be reprogrammed to be an induction location (or vice a versa). Moreover, the induction  104  and discharge  106  conveyors can be used to stage items. The carriages  110  are able to load and unload items on either side and at varying speeds. This adaptability can occur while the conveyor system  100  is operating. Different types of items  1804  can be handled differently. For example, large boxes with high centers of gravity can be discharged from the conveyor system  100  at a slow speed while flatter objects such as envelopes with low centers of gravity can be discharged at high speeds. By controlling the speed of the cross belt  116 , the discharge angle can be varied depending on the item so as to reduce the risk of the item falling off the discharge conveyor  106 . Multiple items can be located on the same carriage  110  or groups of carriages  110  and can be sequenced so as to be discharged at different locations. 
     A technique for handling different items  1804  differently will now be described with reference to  FIGS. 22 and 23 .  FIG. 22  includes a flowchart  2200  that illustrates the various acts performed by the conveyor system  100  using this technique.  FIG. 23  shows a top view of the belt  108  of the conveyor system illustrating how different items are handled differently in accordance with this technique. The acts or stages for this technique will be described as being performed by the control system  208  and the vision system  212  (see e.g.,  FIGS. 2 and 6 ), but it should be recognized that all or part of these acts can be performed, solely or partially, by other components, such as via the sensors  214 , controllers  216 , wireless subsystem  220 , wired gateway  604 , and/or external computer systems, to name just a few examples. 
     In stage  2202 , the control system  208  determines the type of item based on input received from the vision system  212  and/or sensors  214 . For example, the vision system  212  can be used to identify the specific product or SKU being handled by the belt  108 . In another example, the sensors  214  can include a barcode scanner that reads a barcode on the package or SKU so as to determine the type of item or SKU being handled. It should be recognized that the items can be identified in other manners. The title item can be classified in any number of ways. For instance, a simple classification system of large, medium, and small items can be used. Alternatively, the classification of the item type in other examples is complex and can be individualized based on the specific physical and/or handling characteristics of the item  1804 , such as weight, center of gravity, height, dimensions, fragility, etc. 
     The control system  208  in stage  2204  determines the transport or handling requirements for the particular item  1804  identified in stage  2202 . In one example, the control system  208  maintains a database for the particular item type and handling requirements so as to determine the transport handling requirements. In another example, the control system  208  can access (e.g., over the internet) an external database for the transport requirements for particular items. The transport requirements for item types can vary over time. For example, a particular item can be handled one way under low throughput requirements and can be handled in an entirely different way in a high throughput situations. Environmental considerations also can be another factor that impacts the transport requirements for an item  1804 . 
     In stage  2206 , the control system  208  adjusts the speed and/or direction of the belts  116  on the one or more carriages  110  where the item  1804  is located depending on the transport requirements determined in stage  2204 . Looking at  FIG. 23 , depending on the speed of the belt  116 , the discharge angles  2302  for the item  1804  can vary. When the belts  116  are operated at high-speed, the item  1804  can be discharged at a 90° angle. The item  1804  can be discharged at other angles, such as at 30°, 45°, and 67° angles, to name a few. As shown in  FIG. 23 , the items  1804  can be discharged at different sides depending on the item type. Moreover, the speed at which items are loaded or unloaded from the carriages  110  can vary depending on the item. For example, fragile or dangerous items can be slowly induced and discharged from the belt  108 , whereas sturdier items are able to be handled at high speeds. In stage  2206 , the speed, acceleration, deceleration, time duration, and/or direction of the belts can be controlled so as to accommodate different SKUs (e.g., fragile, having a high center of gravity, etc.) as well as having variable discharge or inducement angles (i.e., diverting or inducing SKUs from 45 to 90° angles). Again, how items  1804  are handled can also depend on the particular operational situations. For instance, when demand for the items  1804  are low, the items  1804  can be handled at a slower speed as compared to high demand situations. 
     It should be recognized that the above discussed features can be incorporated into other types of systems than the ones discussed above. For example, while the carriages  110  are configured to facilitate vertical recirculation, it should be recognized that certain select features can be adapted into systems that utilize horizontal recirculation. It should be also recognized that data and/or power can be transmitted in different ways than described above. For instance, contactless data and/or contactless power systems can be incorporated into the system. In another example, the carriages have ultra-capacitors for storing energy from a power rail. Moreover, the acts of the techniques described above can be performed in different sequences and/or can include other steps so they can be adapted for other operational conditions. 
     It should be noted that the singular forms “a”, “an”, “the”, and the like as used in the description and/or the claims include the plural forms unless expressly discussed otherwise. For example, if the specification and/or claims refer to “a device” or “the device”, it includes one or more of such devices. 
     It should be noted that directional terms, such as “up”, “down”, “top” “bottom”, “fore”, “aft”, “lateral”, “longitudinal”, “radial”, “circumferential”, etc., are used herein solely for the convenience of the reader in order to aid in the reader&#39;s understanding of the illustrated embodiments, and it is not the intent that the use of these directional terms in any manner limit the described, illustrated, and/or claimed features to a specific direction and/or orientation. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes, equivalents, and modifications that come within the spirit of the inventions defined by following claims are desired to be protected.