Abstract:
An order picking system includes a robot and pallet support shuttle which i) loads an empty pallet from an empty pallet distribution system, ii) carries the empty pallets adjacent a selected one of a plurality of SKU pallet stations including selected products; iii) charges one or a plurality of the selected products from the selected one of the SKU pallet stations on the one of the empty pallets, iv) repeats steps ii) and iii) until a mixed pallet is completed according to an order; and iv) unloads the mixed pallet onto a mixed pallet receiver to be picked up. The shuttle includes a robot and a pallet-receiving area both moving in unison on a rail. This minimizes robot traveling since the mixed pallet always travels with the robot. The order picking system is enclosed with safety fencing having limited pick and drop areas.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/914,380, filed Apr. 27, 2007, the subject content of which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Order picking, which is often called mix palletizing, is one of many palletizing methods. Order picking is used in distribution centers and warehouses for example where different product types, which may vary in dimensions and content, are manually picked and putted on a same pallet according to a customer order. The products are picked on full SKU (stock-keeping unit) pallets or from racks or shelves. 
         [0003]    Automated or robotized mix palletizing systems and methods are known in the art. However, they involve relatively large floor space in order to allow handling of the many pallets by lift trucks, which further yield an unsecured plan. 
       SUMMARY OF THE INVENTION 
       [0004]    In accordance with a first aspect of the present invention, there is provided an order picking system comprising: 
         [0005]    stock-keeping unit (SKU) pallet stations, each for receiving a SKU pallet including at least one layer of identical products selected from a group of products; 
         [0006]    a mixed pallet receiver; and 
         [0007]    a combined robot and pallet support shuttle for i) receiving an empty pallet, ii) carrying the empty pallet adjacent a selected one of the SKU pallet stations including selected products; iii) charging at least one of the selected products from the selected one of the SKU pallet stations on the empty pallet, iv) repeating steps ii) and iii) until a mixed pallet is completed according to an order; and iv) unloading the mixed pallet onto the mixed pallet receiver to be picked up. 
         [0008]    The combined pallet support and robot shuttle comprises a robot and a pallet, both being mounted on a same shuttle for movement in unison. The robot picks the products from full SKU pallets, located along the path of the shuttle, and places the products on the mixed pallet, which is also secured to the shuttle. This minimizes robot traveling since the mixed pallet always travels with the robot. 
         [0009]    The order picking system is enclosed with safety fencing having limited pick and drop areas. 
         [0010]    Other objects, advantages and features of the present invention will become more apparent upon reading the following non restrictive description of illustrated embodiments thereof, given by way of example only with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a perspective view of an order picking system according to an illustrative embodiment of the present invention; and 
           [0012]      FIG. 2  is a top plan view of the order picking system from  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    While the invention will be described in conjunction with illustrated embodiments, it will be understood that it is not intended to limit the scope of the invention to such embodiments. 
         [0014]    In the following description, similar features in the drawings have been given similar reference numerals, and in order not to weigh down the figures, some elements are not referred to in some figures if they were already identified in a precedent figure. 
         [0015]    An order picking system  10  according to an illustrative embodiment of the present invention will now be described with reference to  FIGS. 1 and 2 . As will be described hereinbelow in more detail, the system  10  allows forming mixed pallets  24  using products  25   a - 25   j  provided on single stock-keeping unit (SKU) pallets  26 . 
         [0016]    The order picking system  10  comprises a plurality of single SKU pallet stations  12 , a SKU pallet distribution system  14 , an empty pallet distribution system  16 , a robot and pallet support shuttle  18 , a mixed pallet receiving system  20 , an empty pallet receiving system in the form of an empty pallet restacker  21  and a system controller, in the form of programmable logic controller (PLC)  22 . Each of the sub-systems  12 - 22  will now be described in more detail. 
         [0017]    The robot and pallet support shuttle  18 , which will simply be referred herein as the “shuttle” for concision purposes, includes a motorized carriage (not shown) slidably mounted on a rail  28  via for linear bearings so as to be movable along a shuttle path defined by the rail  28 . The motorized carriage includes a conventional servo motor drive (not shown) to drive the shuttle  18  along the rail  28 . The shuttle  18  includes a controller  30 , which is coupled to and triggered by the PLC  22 , to precisely control the movement and position of the motorized carriage along the rail  28  and the operations of the robot  36  with tool  38  as will be described hereinbelow in more detail. 
         [0018]    Different controllers can alternatively be provided for each component of the shuttle  18  and/or of the system  10 . Since controllers for motorized drives, robots and tools, etc. are believed to be well-known in the art of palletizing and de-palletizing, the controller  30  will not be described further herein. 
         [0019]    The motorized carriage of the shuttle  18  supports and moves in unison a SKU pallet mover  32 , a pallet-receiving area  34  and a robot  36  provided with a palletizing/depalletizing tool  38  both mounted on the carriage between the pallet mover  32  and the pallet-receiving area  34 . The motorized carriage, the SKU pallet mover  32 , the pallet-receiving area  34  and the robot  36  with the tool  38  together define the robot and pallet support shuttle  18 . 
         [0020]    The SKU pallet mover  32  allows positioning single SKU pallets  26  at selected pallet stations  12 . For that purpose, the pallet mover  32  includes a pallet receiving table  40  and two parallel jaw members  42  mounted to the table  40  on opposite sides thereof so as to be movable towards and away each other. The two jaw members are also slidably mounted to the table  40  for reciprocal movements towards and away selected pallet stations  12 . The two jaw members  42  together form a jaw which can be close on a SKU pallet for pick up. 
         [0021]    In operation, the pallet mover  32  first opens its jaw  42 . The jaw  42  then moves about the selected pallet  26 . The jaw  42  then closes on the base of the selected pallet  26  and slides back on the receiving table  40 . The opposite operation is performed after the shuttle  18  is positioned in front of a selected SKU pallet station  12 . 
         [0022]    The pallet mover  32  can take other form allowing to move a single SKU pallet  26  brought by the SKU pallet distribution system  14  to an empty one of the pallet stations  12 . For example, according to a further illustrative embodiment of the present invention, the pallet mover includes a motorized conveyor (not show) which can selectively move pallets in either one of two opposite directions. According to this further illustrative embodiment, each of the pallet stations is in the form of a conveyor (not shown) which is selectively coupled to the pallet mover when the pallet mover is registered therewith so as to be motorized therefrom. 
         [0023]    The pallet receiving area  34  is defined by a movable fork (not shown) mounted to the carriage. The fork allows receiving an empty pallet  56  and dropping a mixed pallet  24  formed thereon by the robot  36  at the unloading end  37  of the rail  28  to be picked up by the mixed pallet receiving system  20 . It is to be noted that the fork is commanded by the PLC  22 . 
         [0024]    The robot  36  is in the form of a conventional palletizing robot such as model no. IRB 660 by ABB. Of course, other robots allowing for example movements about four (4) or six (6) axis can also be used. 
         [0025]    The palletizing/depalletizing tool  38  is configured for mix-palletizing and more specifically for gripping products from different sizes on the pallets  26 . The tool  38  includes a vacuum, side grippers, a fork tool or any combination thereof. 
         [0026]    A tool such as the one described in US published patent application no. US-2007-0280812-A1 titled “Tool and Method for Mixed Palletizing/Depalletizing” by Axium, Inc. and which is incorporated herein by reference can for example be used. 
         [0027]    The SKU pallet stations  12  (twelve (12) according to the illustrated embodiment) are defined by a plurality of pallet receiving areas on two elongated flat surfaces  44  parallel to the rail  28  on both sides thereof. The two elongated surfaces  44  are defined by rectangular tables  46 . 
         [0028]    According to a further illustrative embodiment (not shown), the pallet receiving areas are defined by rectangular frames having a width sufficient to receive SKU pallets  26 . 
         [0029]    The controller  30  of the shuttle  18  is so programmed that the shuttle  18  picks up SKU pallets  26  provided by the SKU pallet distribution system  14  and drops them at a selected one of the SKU pallet stations  12 , which is of course empty. The two elongated surfaces  44  are so positioned relatively to the rail  28  that the pallet stations  12  are within the reach of the robots  36 . 
         [0030]    Even though the system  10  includes two elongated flat surfaces  44  parallel to the rail and positioned on opposite sides thereof, the SKU pallet stations can all be positioned on a same side of the rail. According to a further illustrative embodiment of an order picking system according to the present invention, the rail  28  defines a non linear path and the SKU pallet stations are complementary not linearly positioned. 
         [0031]    The number, position and size of the pallet stations  12  may vary. 
         [0032]    The SKU pallet distribution system  14  includes two full SKU pallet infeed conveyors  48 , each aligned with a respective one of the two elongated flat surfaces  44 . The infeed conveyors  48  receive single SKU pallets  26 , each including layers of identical products  25   a ,  25   b ,  25   c ,  25   d ,  25   e ,  25   f  or  25   j . Each of the pallet stations  12  may receive SKU pallets including unique products or two different pallet stations may receive identical single SKU pallets  26  depending on the application. The system  10  and more specifically the controller  22  may also be configured so as to dynamically determine the position of new single SKU pallet  26  according to the nature of the product it includes and the availability of the SKU pallet stations  12 . 
         [0033]    The single SKU pallets  26  are loaded on the feed conveyors  48  using for example a truck lift  50 . Other means may also be used to load the SKU pallets onto the input conveyors  48 , including without limitations further conveyors (not shown) operatively coupled to the conveyors  48 . The length and configuration of the feed conveyors  48  may differ relatively to those illustrated in  FIGS. 1-2 . 
         [0034]    The empty pallet distribution system  16  includes an empty pallet dispenser  52  and an empty pallet infeed conveyor  54  operatively coupled to the empty pallet dispenser  52  for receiving empty pallets  56  therefrom and for feeding the empty pallets  56  to a dual-purpose conveyor  58  which is positioned at the end  37  of the rail  28 . 
         [0035]    The empty pallet dispenser  52  allows receiving a stack of empty pallets  56  and dropping at once a single empty pallet  56  onto the empty pallet infeed conveyor  54 , which extends within the frame  60  of the pallet dispenser  52  so as to be positioned under the stack of pallets  56 . Since the mechanism and operation of such an empty pallet dispenser  52  is believed to be well-known in the art of palletizing, and for concision purposes, the empty pallet dispenser  52  will not be described further herein. 
         [0036]    The mixed pallet receiving system  20  is in the form of a conveyor abutted to the dual-purpose conveyor  58 . A truck-lift  50  or any other apparatus (not shown) for unloading and carrying pallets is used to unload a mixed pallet  24  from the conveyor  20 . A further conveyor can alternatively be used to receive and unload mixed pallets  24  from the pallet-receiving system  20 . 
         [0037]    The empty pallet infeed conveyor  54 , dual purpose conveyor  58  and mixed pallet receiving conveyor  20  are all leveled and are motorized so as to move pallets  24  and  56  in a direction from the empty pallet dispenser  52  to the unloading end  62  of the mixed pallet receiving conveyor  20 . 
         [0038]    According to a further illustrative embodiment of the present invention, a single conveyor (not shown) acts as the empty pallet conveyor  54 , the dual purpose conveyor  58  and the mixed pallet receiving conveyor  20 . 
         [0039]    The empty pallet restacker  21  is positioned by the rail  28  adjacent the end  37  thereof. The empty pallet restacker  21  receives and stacks empty pallets  56  from the shuttle  18 . Other means than the empty pallet restacker  21 , allowing to receive an empty pallet  56  from the shuttle  18  and to dispose thereof can also be used. Such means may include, without limitations, a conveyor provided with pallet gripping means. 
         [0040]    The controller  22  allows controlling and coordinating the operation of the components of the system  10 , including the shuttle  18 , the conveyors  20 ,  48 ,  54  and  58 , pallet dispenser  52  and empty pallet restacker  21 . Since such a controller is believed to be well-known in the palletizing and conveyor arts and for concision purposes, it will not be described further herein in more detail. 
         [0041]    The order picking system  10  is enclosed with safety fencing  64  having only four openings, defining the following pick and drop areas: the two full SKU pallet infeed conveyors  48 , the mixed pallet outfeed which is defined by the mixed pallet receiving conveyor  20 , and the pallet restacker  21 . It is to be noted that it is the fact that the system  10  allows for limited pick and drop areas which allows its securing with fences  64 . 
         [0042]    At the beginning of the operation of the order picking system  10 , the system shuttle  18  loads each pallet station  12  with a single SKU pallet  26 . More precisely, the shuttle  18  moves in front of the full SKU pallet infeed conveyors  48 , the pallet mover  32  loads a single SKU pallet  26  on the shuttle  18 , and unload the single SKU pallet  26  on a selected one of the empty pallet station  12 . This sequence is repeated until the pallet stations  12  located along the rail  28  are loaded with a single SKU pallet  26 . 
         [0043]    A person skilled in the art would appreciate that the system  10  does not require that all pallet stations  12  be full in order to operate. 
         [0044]    The controller  22  memorizes the type of products at each pallet station  12 . 
         [0045]    This sequence is also repeated when a single SKU pallet  26  becomes empty and has to be replaced. The empty pallet  56  is then moved by the shuttle  18  to the pallet restacker  21 . Then the step of placing a new single SKU pallet  26  starts again. 
         [0046]    Afterward, when the stations  12  includes a required single SKU pallet  26 , the shuttle  18  is moved adjacent a selected pallet station  12 , the robot  36  picks products on the corresponding single SKU pallet  26  using its mix-palletizing tool  38  and puts the products on the pallet receiving area  34 . 
         [0047]    The number of products simultaneously picked by the robot  36  depends on the capability of the tool  38  and/or on the customer order. Indeed, in operation, the system  10  proceeds in such a way that the shuttle  18  picks products and assembles a mixed pallet  24  according to an order inputted into the controller  22 . For example, the robot  36  picks one product or a row of products or a full layer of products. 
         [0048]    When the mixed pallet  24  is completed according to the order inputted in the controller  22 , the shuttle  18  moves to the dual-purpose conveyor  58  and unloads the mixed pallet  24  thereon. The mixed pallet  24  is then moved to the unloading end  62  of the mixed pallet receiving conveyor  20  by the conveyors  58  and  20  to be picked up for example by a lift truck  50 . 
         [0049]    Finally, the shuttle  18 , which is still positioned at the end  37  of the rail  28 , lowers its fork towards the dual purpose conveyor  58  to load an empty pallet  56  which has been placed there by the empty pallet infeed conveyor  54  and which has been previously dropped by the pallet dispenser  52 . 
         [0050]    It is to be noted that the single SKU pallets  26  of the pallet stations  12  are handled by the shuttle  18  and not by lift trucks. This allows limiting access to the system  10  during operation thereof. The system  10  allows a single robot  36  to palletize a high number of different products in a secure environment since lift truck access is limited to four pick and drop areas: one mixed pallet exit conveyor  20 , two full SKU pallet infeed conveyors  48  and the pallet dispenser  52 . 
         [0051]    Moreover, the system  10  allows minimizing the floor space. 
         [0052]    An order picking system according to the present invention can be used in places such as distribution centers and warehouses for example. 
         [0053]    It is to be noted that many modifications could be made to the order picking system  10  described hereinabove for example:
       Even though the system  10  is illustrated in  FIGS. 1 and 2  with SKU  25   a - 25   j  in the form of carton, the SKU pallets may includes any stackable products such as corrugated boxes (closed or open), plastic containers, corrugated trays, carton stacks and bags;   The conveyors  20 ,  48 ,  54 ,  58  can be of the belt conveyor type, roller conveyor type, etc.;   The shuttle  18  can be made movable by other means than a carriage on a rail. For example, sliding elements can be used on both the carriage and the ground. Also, an automated guided vehicle (AGV) can for example alternatively be used;   The SKU pallet mover  32  can be omitted on the shuttle  18  and other means can be provided to move the single SKU pallets  26  from the SKU pallet distribution system  14  to selected pallet stations. For example, forks or any other pallet handling means mounted on a gantry (not shown) positioned adjacent the surface  44  can alternatively be used.       
 
         [0058]    It is to be understood that the invention is not limited in its application to the details of construction and parts illustrated in the accompanying drawings and described hereinabove. The invention is capable of other embodiments and of being practiced in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose of description and not limitation. Hence, although the present invention has been described hereinabove by way of illustrative embodiments thereof, it can be modified, without departing from the spirit, scope and nature of the subject invention as defined in the appended claims.