Abstract:
A compact and high capacity sorting system includes a transportation vehicle travelling along a travelling route where the transportation vehicle may diverge and merge, and raising and lowering a transfer device; racks provided along the travelling route and having a height corresponding to multiple floors; an arrival area, a shipment area, and a sorting area, each provided along an outer periphery of the travelling route; and a controller controlling the transportation vehicle to transport commodities from the arrival area to the sorting area via the racks, and transport commodities from the sorting area to the shipment area.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a sorting system and a sorting method. 
         [0003]    2. Description of the Related Art 
         [0004]    Conventional sorting systems have an automated storage and retrieval warehouse including a rack and a stacker crane. The warehouse is connected to peripheral stations via rail-guided vehicles. The conventional sorting systems perform sorting in combination with a long range conveyor, a vertical conveyor, and so on. Therefore, the conventional sorting systems need a wide variety of transportation equipment and transportation vehicles. Also, the system architecture of the conventional sorting systems is complicated. 
         [0005]    JP S63-242809A proposes to transport articles by overhead travelling vehicles in a factory among an arrival area, the racks of a storage, and an assembly line. Further, according to JP S63-242809A, the travelling route of the overhead travelling vehicles is provided with diverging sections and merging sections, and therefore, the overhead travelling vehicles may have access to the racks. However, JP S63-242809A does not deal with the sorting of articles. 
       SUMMARY OF THE INVENTION 
       [0006]    Preferred embodiments of the present invention provide a sorting system and a sorting method preferably using one kind of transportation vehicle, and being compact in size and highly efficient. 
         [0007]    A sorting system according to a preferred embodiment of the present invention, for sorting and shipping commodities, includes a transportation vehicle including a transfer device and traveling along a travelling route to diverge and merge and to raise and lower the transfer device; racks provided along the travelling route and having a height corresponding to multiple floors; an arrival area, a shipment area, and a sorting area along an outer periphery of the travelling route; and a controller configured or programmed to control the transportation vehicle so that the transportation vehicle transports the commodities from the arrival area to the sorting area via the racks and transports the commodities from the sorting area to the shipment area. 
         [0008]    A sorting method for sorting and shipping commodities using a sorting system including a transportation vehicle including a transfer device and traveling along a travelling route to diverge and merge and to raise and lower the transfer device, racks provided along the travelling route and having a height corresponding to multiple floors, an arrival area, a shipment area, and a sorting area along an outer periphery of the travelling route, and a controller, the method including transporting the commodities from the arrival area to the sorting area via the racks and transporting the commodities after sorting from the sorting area to the shipment area by the transportation vehicle under control of the controller. 
         [0009]    According to various preferred embodiments of the present invention, the transportation vehicle travels along the travelling route that enables the transportation vehicle to diverge and merge so that the transportation vehicle is able to access a wide range of racks. Thus, the controller may cause the transportation vehicle to perform transportation from the arrival area to the rack, transportation from the rack to the sorting area, and transportation from the sorting area to the shipment area and the rack. Therefore, a plurality of different types of transportation devices, such as a stacker crane, rail guided vehicles, and a long range conveyor are not needed. Further, the arrival area, the shipment area, and the sorting area are arranged along the travelling route, and as a result, the sorting system is compact in size. 
         [0010]    According to various preferred embodiments of the present invention, compact and highly efficient sorting systems and methods capable of using only one kind of transportation device are provided. 
         [0011]    In preferred embodiments of the present invention, sorters that separate commodities according to their shipping destinations without storing the commodities for a long period as the stock, and pickers that store the commodities as the stock are different from each other. 
         [0012]    Preferably, the arrival area and the shipment area are provided on a ground floor so that the entrance and the exit of trucks are made easy, and the sorting area is provided on at least an upper floor, in particular, preferably on multiple upper floors so that the system building requires a small site area. 
         [0013]    Preferably, the travelling route includes rails provided in a ceiling space of a building accommodating the sorting system, and the transportation vehicle includes a carriage that travels along the rails; at least a mast suspended from the carriage; and an elevation platform including the transfer device and that is able to be raised and lowered along the mast. While a mast vertically standing from a carriage running on the ground may fall, the mast suspended from the carriage in the ceiling space has no risk of falling and is able to be made lighter in weight. Also, a ground carriage supporting the mast can be made lighter in weight or omitted. Further, when the carriage is made lighter, then the ceiling rails can be made lighter. 
         [0014]    Preferably, the transportation vehicle preferably includes a pallet transportation vehicle and a case transportation vehicle, and both the pallet transportation vehicle and the case transportation vehicle are able to travel along the rails. The case transportation vehicle performs sorting in case units, and the pallet transportation vehicle transports pallets before sorting and pallets after sorting. Further, the pallet transportation vehicle and the case transportation vehicle travel along the common travelling route, and, in particular, it is more efficient when both the pallet transportation vehicle and the case transportation vehicle are able to travel along the entire travelling route. 
         [0015]    The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a plan view showing a layout of a sorting system according to a preferred embodiment of the present invention. 
           [0017]      FIG. 2  is a side view of a sorting system according to a preferred embodiment of the present invention. 
           [0018]      FIG. 3  is a schematic diagram showing expansions of a sorting system according to a preferred embodiment of the present invention. 
           [0019]      FIG. 4  is a side view of an overhead travelling vehicle according to a preferred embodiment of the present invention. 
           [0020]      FIG. 5  is a fragmentary enlarged front view of an overhead travelling vehicle according to a preferred embodiment of the present invention. 
           [0021]      FIG. 6  is a plan view showing two kinds of overhead travelling vehicles travelling on a common rail according to a preferred embodiment of the present invention. 
           [0022]      FIG. 7  is a front view of a case pallet used in a preferred embodiment of the present invention. 
           [0023]      FIG. 8  is a block diagram showing a control system according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    The following describes preferred embodiments of the present invention. The scope of the present invention shall be construed based upon the claims and according to the understanding of a person skilled in the art with reference to the specification. 
         [0025]      FIGS. 1-8  show sorting systems according to preferred embodiments of the present invention.  FIGS. 1 and 2  show a layout of a sorting system  2 . An automated storage and retrieval warehouse  4  includes ceiling rails  6  in a ceiling space, and a travelling route including the ceiling rails  6  with plural diverging and merging sections  8  so that plural overhead travelling vehicles  10  travel along the ceiling rails  6  and diverge and merge autonomously. While the ceiling rails (in the following, “rails”)  6  may allow bi-directional travelling, the overhead travelling vehicles preferably travel uni-directionally according to the present preferred embodiment, for example. Plural racks  20  are provided along the rails  6 , and the overhead travelling vehicles  10  may access any cell of any of the racks  20 . 
         [0026]    An arrival area  22  is provided on a ground floor of the sorting system  2  and is adjacent to one end of the automated storage and retrieval warehouse  4 . A shipment area  24  is provided on the same ground floor and is adjacent to the other end of the automated storage and retrieval warehouse  4 . The arrival area  22  and the shipment area  24  are provided along the outer periphery of the travelling route including the rails  6 , may be adjacent to the side surface of the automated storage and retrieval warehouse  4 , and are respectively provided with station arrays  26  each including a row of stations  28 . Further, the overhead travelling vehicles are structured and operative to transfer a pallet, a case, and the like at each station  28 , for example. Further, the areas  22 ,  24  are provided with berths  30 , respectively, and operators may input arrival data via arrival terminals  32  in the arrival area  22  and may require transporting of the arrived commodities into the rack  20  via the terminal. The operators may input shipment data via shipment terminals  34 . The sorting system  2  includes a controller  36  configured or programmed to control the system, and the controller include a single computer or plural distributed computers, for example. 
         [0027]    Since all of the overhead travelling vehicles are not required to operate at all times, it is preferable to provide at least a retreating lane  12  to accommodate retreating overhead travelling vehicles  10  that are not operating so as to save power consumption. The retreating lane  12  preferably includes a maintenance deck  14  to make the maintenance of elevation platforms and carriages of the overhead travelling vehicles easier. The retreating lane  12  is, for example, provided at a position not facing the rack  20 . 
         [0028]    With respect to the overhead travelling vehicle  10 , a carriage  40  travels along the ceiling rail  6 , and a front mast  42  and a rear mast  42  are suspended from the carriage  40  by unshown pins, and so on, so that the masts may rock along the travelling direction. Along the masts  42 ,  42 , an elevation platform  44  raises and lowers, and the front and rear masts  42 ,  42  are connected by a connection portion  46  at their lower ends. The overhead travelling vehicle  10  may be a stacker crane in which a travel drive mechanism and an elevation drive mechanism are provided in the carriage  40  at the ceiling space and the mast  42  is capable of rocking. 
         [0029]    In the upper floors over the areas  22  and  24 , sorting areas  50  are provided over multiple floors along the outer periphery of the travelling route including the ceiling rails  6 , and the overhead travelling vehicles  10  transport pallets and cases, and so on, to and from the sorting area  50  via the stations  28 . In the sorting areas  50 , articles on pallets are sorted in case units where the cases may include cardboard boxes, and so on, and are loaded on pallets, and so on, for respective destinations, or individual commodities are taken out of pallets and are sorted into cases such as buckets. Sorting terminals  51  receive and display instructions regarding sorting from the controller  36  and respond the sorting results to the controller  36 . The sorting areas may be equipped with arbitrary sorting devices, and, for example, sorters  52  take out cardboard boxes from pallets one by one and load them on case pallets  86  shown in  FIG. 7 . 
         [0030]    The sorting system  2  may be expanded successively, and this situation is shown in  FIG. 3 . In  FIG. 3 , symbol ′ indicates elements after expansion, and the numeral  2 , and so on, in  2 ,  2 ′, and so on, indicates elements of the same species. For example, a first sorting system  2  in the upper row in  FIG. 3  may be expanded into a sorting system  2 ′ and may further be expanded into a sorting system  2 ″. 
         [0031]      FIGS. 4 and 5  illustrate the structure of the overhead travelling vehicle (in the following, “vehicle”)  10 . The rails  6  are fixed under the ceiling  5  of a building including mutually connected self-standing racks  20 , and the rails  6  include a row of permanent magnets  54  and contactless electrical feeding lines  56 . On the bottom portion of the rails  6  are provided left and right guide rails  58 ,  58  for the selection between diverging and traveling straight ahead and also to control the posture during merging. The carriage  40  of the vehicle  10  is provided with travelling units  59 . A combination of a coil  60  of the travelling units  59  and the permanent magnets  54  of the rails  6  constitutes a linear motor. Power receiving coils  62  receive electricity from the contactless electrical feeding lines  62 , and wheels  64  support the weight of the vehicle  10 . Further, the travelling units  59  are equipped with left and right guide rollers  66 ,  66 , and a travelling controller  68  causes the guide rollers  66 ,  66  to be advanced and retracted between a position guided by the guide rail  58  and a position not guided. Thus, the vehicle  10  diverges and merges autonomously, however, as is taught in JPS63-242809A, diverging and merging are controlled by a movable mechanism provided in the rails  6 . 
         [0032]    A chassis  71  of the carriage  40  is attached to a vertical shaft  70  of the travelling unit  59 , and the front and rear masts  42  are attached to the chassis  71  by unshown pins, or the like, so that they may rock along the travelling direction. A chain  76  is driven by a motor  72  and sprocket  74  of the chassis  71  so as to raise and lower the elevation platform  44  and an unshown counter weight. Guide rollers  78  of the elevation platform  44  are guided by the masts  42  so as to restrict the vibrations and twists of the elevation platform  44 , and a transfer device  80 , such as a slide fork, transfers pallets  82  and so on. Articles  84  are located on a pallet  82 . Further, another driver such as a belt may be used in place of the chain, and the counter weight may be omitted. 
         [0033]    The lower ends of the front and rear masts  42  are connected by a connection portion  46  which is, for example, horizontal, and a portion of the weight of the vehicle  10  is supported by a ground rail  48  via wheels  47 . Unshown guide rollers are guided by the ground rails  48  in order to further restrict the vibrations and twists of the masts  42 . Since the masts  42  are capable of rocking along the travelling direction, the travelling units  59  are controlled not to accelerate or decelerate at or in a vicinity of the intrinsic frequency of the masts in order to significantly reduce or prevent the vibrations of the masts  42 . Further, unshown dampers, damping rubbers, shock absorbers, or the like, are provided in the connection portion between the masts  42  and the chassis  71  so as to reduce the vibration during emergency stops. The connection portion  46  and the ground rails  48  may be omitted, and the number and the structure of the masts  42 , or the like, is arbitrary. 
         [0034]    Since the sorting system  2  preferably performs sorting from the pallets  82  to cases, it is preferable to provide other overhead travelling vehicles transporting articles in case units than the overhead travelling vehicles  10  transporting articles on pallets and to make them travel along the same ceiling rails  6 . This situation is illustrated in  FIG. 6 . An overhead travelling vehicle designated by  10 ′ transports articles in case units, has a smaller number of travelling units  59  than the overhead travelling vehicles  10 , and includes an elevation platform  44 ′ having a narrower width along the travelling direction than the elevation platform  44 . Further, a transfer device  85 ′ has a narrower width to support an article along the travelling direction of the rails  6  than the transfer device  85  has. However, it is preferable to make the length of the transfer devices  85  and  85 ′ equal or substantially equal along a perpendicular direction to the travelling direction of the rails  6  in a horizontal plane so that both the overhead travelling vehicles  10  and  10 ′ are capable to transfer articles between each cell of the racks  20  and between each station  28 . The overhead travelling vehicles  10 ′ are configured similarly to the overhead travelling vehicles  10  in other points. Plural transfer devices  85 ′ may be provided on the elevation platform  44 ′ so as to transport plural cases simultaneously. 
         [0035]      FIG. 7  shows the case pallet  86 . The case pallet  86  is transported by the overhead travelling vehicles  10  in a similar manner with the pallet  82 , is placed in each cell of the rack  20 , and is transported into the sorting area  50  and the shipment area  24 , or the like, via the stations  28 . The case pallet  86  includes a base  87  from which pillars  89  stand, a plurality of article supports  88  are fixed to the pillars, and a case  70  such as a cardboard box or a bucket is placed on each of the article supports  88 . 
         [0036]    The cases are transferred by the sorter  52  shown in  FIG. 2 , or the like, from the pallets  82  onto the case pallets  86  which are placed in the rack  20  and on the stations  28 , and so on. The overhead travelling vehicles  10 ′ sort cases  90  among the case pallets  86 ,  86  to complete the sorting, and after that the overhead travelling vehicles  10  ship the case pallets  86 . 
         [0037]      FIG. 8  shows the control system of the sorting system  2 . The controller  36  communicates with the terminals  32 ,  34 ,  51 , receives orders regarding the sorting from a host controller  92 , controls the overhead travelling vehicles  10 ,  10 ′, the sorters  52 , and so on, to cause the sorting to be carried out, and reports the execution results to the host controller  92 . 
         [0038]    The present preferred embodiment preferably includes the following features. 
         [0039]    The arrival area  22  and the shipment area  24  are preferably provided on the ground floor, the sorting areas  50  are provided on the upper floors, and the overhead travelling vehicles  10  are caused to travel along the travelling route which allows diverging and merging. As a result, a compact sorting system in size is provided. 
         [0040]    Since the overhead travelling vehicles  10  and  10 ′ are able to diverge and merge and to move to any of the racks  20  and any of the stations  28 , one kind of transporting devices is basically enough. 
         [0041]    The overhead travelling vehicles  10  and  10 ′ are enough, if they are able to support the vertical weight added to the masts  42 , and are not required to have the rigidity along the travelling direction. Further, the ground carriage may be a simple one or be omitted. Therefore, the overhead travelling vehicles  10  and  10 ′ are lighter in weight than conventional stacker cranes. Since the overhead travelling vehicles  10  and  10 ′ are lighter, the ceiling rails  6  are also made lighter in weight. 
         [0042]    Since the linear motor is preferably used, the rails  6  are not subjected forces along the travelling direction. Therefore, the rails  6  are made even lighter in weight. 
         [0043]    The retreating lane  12  contributes to power saving and the maintenance deck  14  makes the maintenance of the overhead travelling vehicles  10  and  10 ′ easier. 
         [0044]    The sorting system  2  is easily expanded. 
         [0045]    The travelling units  59  may be commonly used in both the travelling vehicles  10  and  10 ′. 
         [0046]    The overhead travelling vehicles  10  transport the pallets, and the overhead travelling vehicles  10 ′ may transport cases and sort articles in case units. 
         [0047]    While in the present preferred embodiment the overhead travelling vehicles  10 ′ preferably sort articles in case units, other overhead travelling vehicles equipped with an elevation platform including both the transfer device  85  for pallets  82  and the transfer device  85 ′ for cases  90  may be used. The overhead travelling vehicles perform functions of both the travelling vehicles  10  and  10 ′. Further, the species of the sorting devices provided in the sorting areas  50 , the details of the sorting operations, the distribution of the sorting operations between operators and the sorting devices, and so on, are arbitrary. 
         [0048]    While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.