Abstract:
A transfer shuttle for transferring a load between a pair of multi-tier racks in an automatic warehouse has a traveling platform traveling between the multi-tier racks, extension and retraction mechanisms arranged at the front and rear of the traveling platform with a load mounting area of the platform sandwiched between the mechanisms, and end fingers arranged at opposite ends of a rail which, among the rails in the extension and retraction mechanism, has the largest movement range and is movable between a protruded position engageable with the load and a standby position. The rail also has an inner finger provided between the end fingers. With such an arrangement, the inner finger can push a load on the load mounting area of the transfer shuttle to convey the load to a position deeper in the multi-tier rack than positions achievable by conventional products.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This patent is a national stage filing under 35 U.S.C. §371 of international application Ser. No. PCT/JP2008/069464 filed in the Japanese Receiving Office on Oct. 27, 2008, the complete disclosure of which is hereby incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       1 . Technical Area 
       [0002]    This patent relates to a three-dimensional automated warehouse with at least one pair of layered stacked racks, and more particularly to transferring shuttles which are placed on every layer, or on every few layers, of the stack of racks, and which run in a horizontal direction and transfers package(s) to and from the layered stacked racks. 
         2 . Technical Background 
       [0003]    A known example of a three dimensional warehouse is described in Japanese Patent Disclosure Heisei 8-324721. The three dimensional warehouse described in this Patent Disclosure is comprised of at least one pair of left and right layered stacks of racks, each containing multiple layers. A transferring shuttle, which can run in a horizontal direction, is implemented for each layer of the stacked racks. 
         [0004]    The purpose of the transferring shuttle is to transfer packages in and out of the pair of stacked racks. The shuttles of the prior art are comprised of a running platform which can carry a package on its center and a picking mechanism which loads and unloads the package in the horizontal sideway (left and right) directions perpendicular to the direction that the platform runs. 
         [0005]    One such prior art picking mechanism described in the Patent Disclosure Heisei 8-324721, is comprised of a three-stage elastic mechanism placed in front and back of the package carrying area. Each elastic mechanism is of well-known structure, comprised of a fixed rail affixed to the running platform, a first sliding rail which is mounted on the fixed rail so that it can slide, and a second sliding rail which is mounted on the first sliding rail so that it can slide. The first and the second sliding rails are connected by a pulley and belt, so that when the first sliding rail slides on the fixed rail, the second sliding rail slides in the same direction as the first sliding rail. Furthermore, the means of actuation of the first sliding rail is comprised of a motor mounted on the running platform, a pinion mounted on the rotating shaft of the motor, and a rack mounted on the first sliding rail that meshes with the pinion. 
         [0006]    On the second sliding rail, there are terminal fingers that operate between the extended position, in which the fingers protrude towards the package carrying area, and the retracted position, in which the fingers are retracted from the package carrying area. By placing the terminal fingers into the extended position so that they can hold the end surfaces of the package, it is possible to load and unload a package. 
         [0007]    There is the ever present issue of increasing the storage capacity of a three-dimensional warehouse, and a number of methods have been proposed. One such method is to place packages far back (i.e., away from the running path of the transferring shuttle) on each of the shelves of the stacked racks, for example, in two rows, back and front. To realize this method, the maximum stroke of the elastic mechanism must be doubled. 
         [0008]    However, in order to increase the stroke of the elastic mechanism, i.e., to improve the general transferring shuttle such as described in Patent Disclosure Heisei 8-324721, the number of sliding rails must be increased to at least three. Increasing the number of wearable members such as sliding rails may lead to breakage. Also, as the device structure becomes more complex, commonization of purchased parts becomes difficult, and the economy of scale becomes less viable, leading to an increase in manufacturing cost. Furthermore, the increase in the thickness of the elastic mechanism necessitates the designing of sufficient space for the sliding rail above the layered stacked rack and increases the needed clearance between the packages, hindering the increase of the storage capacity in the end. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention provides a solution for the aforementioned problems and provides a transferring shuttle which can place more packages on each shelf of the layered stacked racks. 
         [0010]    The transferring shuttle of one embodiment transfers packages in and out of the layered stacked racks, while being deployed in a three dimensional automated warehouse with at least one pair of layered stacked racks. The transferring shuttle is comprised of the following: a platform which can run in a horizontal direction and is equipped with a package carrying area where the package can be transported; elastic mechanisms in the front and rear of the package carrying area with respect to the running direction of the platform, comprised of multiple rails so that they can be extended or contracted in a horizontal direction perpendicular to the running direction of the platform; and terminal fingers placed at the ends of the rails with the maximum excursion among the rails which can assume the extended position in which the fingers protrude towards the package carrying area and the contracted position in which the fingers recede from the package carrying area. The shuttle further includes inside fingers, which can operate between the extended and contracted positions, and which are placed on the rails closest to the package carrying area between the terminal fingers. 
         [0011]    The package can be transferred in and out by placing the terminal fingers in the extended position so that the left and right end surfaces of the package are pushed by the fingers. In the prior art, the packages are pushed by the terminal fingers on the rail; however, in an embodiment of the present invention, having the fingers further inside pushes the package while reducing the overlap between the rails and makes it possible to transfer the package into a deeper position in the layered stacked rack. Thus, it becomes possible to contain more packages in a layered stacked rack. More specifically, two packages in a row (front and back with respect to the direction of the movement of the packages) can be placed with a three-rail elastic mechanism. Also, since there is no need to increase the number of the rails in the elastic mechanism, there is no requirement for extra clearance between the packages. Furthermore, the addition of the inner fingers allows the existing profile (of the steel shape) to be maintained, thereby preventing an increase in production cost. 
         [0012]    In one embodiment, there may be two sets of inner fingers. By having two sets of inner fingers, three packages can be handled simultaneously, depending on the size and shape of the packages (as shown in  FIG. 7C ). Furthermore, the inner fingers may be positioned such that sufficient space exists for placing a package between an inner finger and the terminal finger further away from the inner finger, or between the other inner finger and the other terminal finger. By allowing the terminal finger to travel a distance exceeding the length of two packages placed next to each other in the layered stacked rack adjacent to the terminal finger, it becomes possible to place two packages in a row (front and back). 
         [0013]    Each of the elastic mechanisms may be affixed to the running platform and may include the following: a fixed rail which extends in the horizontal direction perpendicular to the running direction; a first sliding rail mounted on the fixed rail parallel to a horizontal direction which is able to slide along the fixed rail; and a second rail mounted on the first sliding rail parallel to the horizontal direction which is able to slide along the first sliding rail, in the same direction that the first sliding rail slides. In such a case, the terminal fingers and the inner fingers may be placed on the second sliding rail. 
         [0014]    Furthermore, the method of actuation of the first sliding rail may be comprised of an endless belt with teeth on the exterior perimeter and a rack mounted on the first sliding rail which meshes with the teeth on the exterior surface. By using the belt with external teeth, rather than pinions, it becomes possible to extend the first sliding rail beyond the fixed rail. 
         [0015]    Furthermore, in another embodiment, one inner finger is provided. With this construction, two packages can be handled simultaneously. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective drawing partially showing a three dimensional warehouse in which an embodiment of a transferring shuttle may be used; 
           [0017]      FIG. 2  is a side view drawing of the transferring shuttle of  FIG. 1 ; 
           [0018]      FIG. 3  is a plan view drawing of the transferring shuttle of  FIG. 1 , with the interior partially shown; 
           [0019]      FIGS. 4A-C  are schematic drawings showing the motion of the transferring shuttle of  FIG. 1 ; 
           [0020]      FIGS. 5A-B  are schematic drawings showing the principle of the elastic mechanism used in the transferring shuttle of  FIG. 1 ; 
           [0021]      FIGS. 6A-C  are schematic drawings showing inner fingers and other components of the transferring shuttle of  FIG. 1 ; and 
           [0022]      FIGS. 7A-C  are schematic drawings of a number of variations of the transferring shuttle. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0023]      FIG. 1  is a perspective drawing partially showing a three dimensional warehouse  12  in which an embodiment of a transferring shuttle  10  is used. The three-dimensional automated warehouse  12  shown in the figure contains at least one pair of layered stacked racks  16 L,  16 R made of multiple layers of shelves  14 . Transferring shuttle  10  may be implemented between the layered stacked racks  16 L,  16 R for every layer, or every few layers, of layered stacked racks  16 L,  16 R, in order to transfer packages P. In this implementation, the layered stacked racks  16 L,  16 R store packages P with fixed shape, such as baskets, plastic containers, etc. The depth (the distance in the left-right direction of  FIG. 1  indicated by arrow L-R) of the shelf  14  in the layered stacked racks  16 L,  16 R is double the depth of the prior art. Because of the function of the transferring shuttle  10 , it is possible to place two packages P side by side (i.e. aligned in direction L-R on the same shelf  14 ). 
         [0024]    Not shown in the figure are relaying station(s) which is (are) placed at one or both ends of the layered stacked racks  16 L,  16 R in order to exchange the packages between the layered stacked racks  16 L,  16 R and an external transfer system, where the packages are exchanged with the layered stacked racks  16 L,  16 R via the transferring shuttle  10  and the packages may be temporarily stored. An elevator device, which exchanges the packages between the relaying station and the external transfer system, is also not shown. The relaying stations, external transfer system, and elevator devices may take on known configurations. 
         [0025]    Transferring shuttle  10  is equipped with a running platform  18  which runs in a front-back (see arrows F-B of  FIG. 1 ) horizontal direction between the left and right layered stacked racks  16 L and  16 R. The chassis sections  20 F,  20 B, containing the driving motor, electrical power source, control unit (not shown), etc., are located at the front and the back sides of the running platform  18 . Running wheels  22  are located on each of the left and the right sides of each of the chassis sections  20 F,  20 B. The running wheels  22  are mounted on the guide rails  24  which extend in the horizontal direction (F-B) and are placed on each layer of the layered stacked racks  16 L,  16 R. Thus, the running platform  18  can move forward or backward by rotating at least one running wheel  22  using the driving motor contained in the chassis section  20 F or  20 B. 
         [0026]    The part of running platform  18  between the front chassis section  20 F and the back chassis section  20 B is the package carrying area  26 , which carries the package P. More precisely, the base frame  28  connects the lower parts of the front and back chassis sections  20 F and  20 B, and a pair of package carrying plates  30  are placed horizontally on the base frame  28 , comprising the bottom surface of the package carrying area  26 . The side guide  32  is created on the outer edge, which is the edge towards the adjacent chassis section  20 F or  20 B, of each package carrying plate  30 , and the distance between the side guides  32  is slightly larger than the width of the package P. Thus, the package P can be moved in the transverse (left-right) direction on the package carrying plates  30  without rotating or shifting excessively. The length of the package carrying area  26 , i.e. the transverse left-right dimension, is made sufficiently large to accept normally handled packages P. 
         [0027]    A pair of elastic mechanisms  34 F,  34 B, which are for loading and unloading the package P, are placed at the chassis sections  20 F,  20 B and surround the package carrying area  26 . The elastic mechanisms  34 F,  34 B are actuated in synchronized fashion, and are used to transfer the package between the package carrying area  26  and the shelves  14  of the layered stacked racks  16 L,  16 R. 
         [0028]    Each of the elastic mechanisms  34 F,  34 B is comprised of a fixed rail  36  that is affixed onto the inner surfaces, i.e. the surfaces that face the package carrying area  26 , of the chassis sections  20 F,  20 B, and that extends in the transverse direction (L-R), i.e. the horizontal direction perpendicular to the running direction (F-B) of the running platform. A first sliding rail  38  is mounted on the fixed rail  36  so that it can slide in the same horizontal direction (L-R). A second sliding rail  40  is mounted on the first sliding rail  38  so that it can slide in the same horizontal direction, with the maximum range of motion. The rails  36 ,  38  and  40  have effectively the same length, which is effectively equal to the width of the running platform  18  including the running wheel  22 . When the running platform  18  is in motion, the rails  36 ,  38  and  40  are in the contracted position as shown in  FIG. 2 ,  FIG. 3  and  FIG. 4A , and the rails will not protrude from the side surface of the running platform  18 . On the other hand, when the package P is exchanged with one of the layered stacked racks  16 L,  16 R, the rails will be in the extended position shown in  FIG. 4B . The dimensions of the rails  36 ,  38  and  40  of the elastic mechanisms  34 F and  34 B are determined so that, under the maximum extension, the tip of the second sliding rail  40  reaches the point beyond the depth of two packages side by side (plus the necessary clearance). 
         [0029]    The mechanism of extending and contracting the elastic mechanism  34 F and  34 B is of already known kind as shown in  FIG. 5 , which shows the principle of the actuation, comprised of pulley  42  and belt (or wire)  44 . When the first sliding rail  38  is moved left or right against the fixed rail  36 , the second sliding rail  40  moves further along the first sliding rail  38  in the same direction. 
         [0030]    The means of actuating the first sliding rail  38  is comprised of a rack  46 , which is formed at the bottom edge of the first sliding rail  38  in its entire length; a timing belt  48  (endless belt with internal teeth) with exterior teeth that mesh with the rack  46 ; and a motor which drives the timing belt  48  (not shown). The timing belt  48  goes around the sprockets that are placed on the left and the right edges of the base frame  28  (see  FIG. 5 ), and the upper part of the timing belt  48  (the side tension is applied to) extends almost the entire space between the left and the right ends of the running platform  18 . Thus, when the elastic mechanisms  34 F and  34 B are in the contracted position, virtually the entire rack  46  on the first sliding rail  38  is engaged with the outer teeth of the timing belt  48 . Also, as long as the outer teeth of the timing belt  48  are engaged with the rack  46 , the first sliding rail  38  can be extended maximally from the fixed rail  36  and the second sliding rail  40  can also be extended by the same distance relative to the first sliding rail  38 . The excursion of the sliding rails  38  and  40  can be increased greatly, compared to the prior art in which a rack and pinion mechanism is used as the means of actuating the elastic mechanism  34 F and  34 B. 
         [0031]    The driving motor to drive the timing belt  48  is not shown in the figures, but it is contained in the chassis section  20 B on the running platform  18  and may be of known construction. 
         [0032]    Terminal fingers  52 L and  52 R, which are to contact the side surface of the package P and push and pull the package, are placed at both ends of the second sliding rail  40  ( FIG. 1 ). Each of the terminal fingers  52 L and  52 R has one end anchored to the shaft of the driving motor (not shown in the figures) embedded in the second sliding rail  40 , and can move between the position shown in the solid line in  FIG. 2  and the position shown in the solid line in  FIG. 3  (shown in a broken line in  FIG. 2 ) by controlling the motor. In the contracted position shown in  FIG. 2 , the terminal fingers  52 L and  52 R are sufficiently retracted from the package carrying area  26  such that the fingers will not interfere with the package P on the package carrying area  26  or the packages on any of the shelves  14  of the layered stacked racks  16 L and  16 R. On the other hand, in the extended position shown in  FIG. 3 , the terminal fingers  52 L and  52 R protrude into the package carrying area  26  and can contact the end surfaces of the package P on the package carrying area  26 . 
         [0033]    Two inner fingers  54 L and  54 R are placed on the second sliding rail  40  between the terminal fingers  52 L and  52 R. The inner fingers  54 L and  54 R have the same shape and dimensions as the terminal fingers  52 L and  52 R, and are mounted on the second sliding rail  40  in the same fashion as the terminal fingers  52 L and  52 R. Each of these inner fingers  54 L and  54 R is placed at the same distance away from the longitudinal center of the second sliding rail  40 . One of the inner fingers (the left inner finger  54 L, for example) is paired with the terminal finger which is further away from the inner finger (the right terminal finger  52 R, in this example) where the distance between these fingers is effectively the equivalent of the package P to be handled. 
         [0034]    The operations of pushing the package P from transferring shuttle  10  to the layered stacked racks  16 L or  16 R and that of pulling the package P from the layered stacked racks  16 L or  16 R onto the transferring shuttle  10  are further elaborated. 
         [0035]    First, consider the case where the package is loaded on the right hand side of the package carrying area  26  of the running platform  18  as shown in  FIG. 4A . In order to place the package P into the deepest part of the shelf  14  of the layered stacked rack on the right hand side  16 R, i.e. the location that is furthest from the transferring shuttle  10 , the inner finger  54 L is moved to assume the extended position. Thereafter, the elastic mechanisms  34 F and  34 B are actuated to extend the sliding rails  38  and  40  towards the right side. As a result, the inner fingers  54 L contact the left side surface of the package P and push the package. At the time the second sliding rail is extended the furthest, the package P reaches the deepest part of the shelf  14  of the layered stacked rack  16 R ( FIG. 4B ). 
         [0036]    It should be easily understood that the extension distance of the sliding rails  38  and  40  should be shorter when the package P is to be placed in a shallower location in the layered stacked rack  16 R, i.e. the location closer to the transferring shuttle  10 , as shown in broken lines in  FIG. 4B . 
         [0037]    On the other hand, when the package is originally placed on the left hand side of the package carrying area  26  of the running platform  18  as shown in  FIG. 4C , the sliding rails  38  and  40  of the elastic mechanisms  34 F and  34 B are first moved to the location further left so that the inner fingers  54 L are to the left of the left hand side surface of the package P. Next, the inner fingers  54 L are put into the extended position, and then the package P can be placed at the deepest location of the shelf  14  of the layered stacked rack  16 R with the procedure described above. 
         [0038]    To place the package P at the shallower position of the layered stacked rack  16 R, i.e. the location closer to the transferring shuttle  10  shown with broken lines in  FIG. 4B , it is not necessary for the elastic mechanisms to follow the procedure described above, but simply by using the left terminal finger  52 L, the package P can be moved in a single stroke. 
         [0039]    The sequence of motion described in paragraph [0037] above includes an extra number of moves, and thus may adversely affect the capacity. This sequence, however, can be avoided if some consideration is made during the procedure of loading the package P onto the transferring shuttle  10 . Normally, the new package P is received at the relaying station (not shown in figures) where the package is temporarily stored in stand-by mode. By having the placement at the relaying station closer (with respect to the movement of the elastic mechanism), both the outer (terminal) and inner finger can reach the package, and depending on the direction of the rack where the package is to be stored, the fingers to be used can be selected. Thus, the procedure described in [0037] above can be avoided. 
       Example 1 
       [0040]    If the relaying station is on the right hand side of  FIG. 4 , and the storage location in the rack is on the right hand side, use the outer (terminal) finger to pull in the package. 
       Example 2 
       [0041]    If the relaying station is on the right hand side of  FIG. 4 , and the storage location in the rack is on the left hand side, use the inner finger to pull in the package. 
         [0042]    It should be obvious that the cases where the relaying station is on the left side can be effectively dealt with by going through a similar (symmetric) set of motions. 
         [0043]    If the storage location is close (to the transferring shuttle), either the outer (terminal) finger or the inner finger can be used in the loading of the package P to avoid the procedure described above in paragraph [0037]. 
         [0044]    On the other hand, when the package P is stored at the close location and is pulled out of the layered stacked rack on the right hand side  16 R and onto the transferring shuttle  10 , any of the two inner fingers  54 L or  54 R, or the outer (terminal) fingers  52 R can be used for retrieving the package P. In other words, starting from the package location shown in broken lines in  FIG. 4B , the elastic mechanisms  34 F and  34 B can be contracted and the package P can be pulled onto the transferring shuttle  10  by left inner finger  54 L. Or the inner fingers  54 L and  54 R can be placed in the contracted position while the right terminal finger  52 R is placed in the extended position, such as shown in  FIG. 4B  by broken lines. In such a case, the right terminal finger  52 R comes into contact with the right end surface of the package P, allowing the package P to be pulled onto the transferring shuttle  10 . 
         [0045]    When shipping out to the relaying station (in this case, the package is pulled in from the storage location in the rack), by following the similar procedure as described above, the procedure described in paragraph [0037] above can be avoided. 
         [0046]    When the package P is placed at the deepest location on the layered stacked rack  16 R, the right terminal finger  52 R is used in order to transfer it. 
         [0047]    It should be obvious for the practitioner that, in order to receive and ship the package P stored in the left layered stacked rack  16 L, the reverse (symmetric) of the procedures described above would complete the tasks. 
         [0048]    Now, using  FIG. 6 , a comparison is made between the construction of transferring shuttle  10  and the construction of prior art shuttles, which are equipped only with the terminal finger  52  on both ends of the second sliding rail  40 . 
         [0049]    In the construction of the prior art, the package P could only be moved through the distance S, which is the maximum excursion of the sliding rail  40 , when the sliding rail  40  is moved from the state shown in  FIG. 6A  to the state shown in  FIG. 6B . On the other hand, in the construction of transferring shuttle  10 , by using the inner finger  54 , as shown in  FIG. 6C , the package P can be moved through the distance of the maximum excursion of the sliding rail  40  plus L, which is the distance between the terminal finger  52  and the inner finger  54 . Thus, the construction of transferring shuttle  10  allows the package P to be stored in the deeper location in the layered stacked racks  16 L,  16 R, enabling the packages P to be stored in two rows, front and back. 
         [0050]    Noting this point, the construction with only one inner finger  54  shown in  FIG. 7A  can be considered. In this construction, two small packages P can be simultaneously transferred. Also, the two inner fingers  54  can be moved closer to the center as shown in  FIG. 7B , allowing simultaneous transfer of packages P like the case shown in  FIG. 7A . Furthermore, in the construction shown in  FIG. 7C , it is possible to transfer three packages P simultaneously. It is not shown in the figures, but the placement of three or more fingers may be considered in order to handle a package P of indeterminate shape. 
         [0051]    Transferring shuttle  10  allows a large range of motion of the elastic mechanisms to be secured, thereby permitting the packages to be transferred in numerous fashions due to the independently operating terminal and inner fingers. For example, in the constructions shown in  FIGS. 1 through 3 , when small packages are to be stored in the right stacked rack, it is possible to store three or more small packages sequentially, starting from the deepest position, by using the right inner finger  54 R. It is also possible to simultaneously handle two small packages or the combination of one small and one medium package, i.e. one of the packages can be pushed with inner finger  54 R while the other is pushed by the left terminal finger  52 L. 
         [0052]    The timing belt is used as the means of actuating the elastic mechanisms. The use of a hydraulic, pneumatic or linear motor for this purpose can also be considered. 
         [0053]    The three-stage elastic mechanism is considered here for the benefit of being able to use the same profile as the prior art, but a two-stage or four-stage elastic mechanism can also be considered. 
         [0054]    In the above description, several favorable embodiments were elaborated in detail, but the scope of this invention is not restricted to the embodiments described above. Needless to state, variations and adaptation of these embodiments are possible, without exceeding the spirit or the scope of this invention.