Patent Publication Number: US-2023150766-A1

Title: Automated storage and retrieval system

Description:
FIELD OF THE INVENTION 
     The present invention relates to a storage grid, an automated storage and retrieval system for storage and retrieval of containers from/to such a storage grid. The present invention also relates to a method for storing and retrieving containers in such a storage grid to access deeper laying containers in a more time efficient manner. 
     BACKGROUND AND PRIOR ART 
       FIG.  1    discloses a typical prior art automated storage and retrieval system  1  with a framework structure  100  and  FIGS.  2  and  3    discloses two different prior art container handling vehicles  201 ,  301  suitable for operating on such a system  1 . 
     The framework structure  100  comprises upright members  102 , horizontal members  103  and a storage volume comprising storage columns  105  arranged in rows between the upright members  102  and the horizontal members  103 . In these storage columns  105  storage containers  106 , also known as bins, are stacked one on top of one another to form stacks  107 . The members  102 ,  103  may typically be made of metal, e.g. extruded aluminum profiles. 
     The framework structure  100  of the automated storage and retrieval system  1  comprises a rail system  108  arranged across the top of framework structure  100 , on which rail system  108  a plurality of container handling vehicles  201 ,  301  are operated to raise storage containers  106  from, and lower storage containers  106  into, the storage columns  105 , and also to transport the storage containers  106  above the storage columns  105 . The rail system  108  comprises a first set of parallel rails  110  arranged to guide movement of the container handling vehicles  201 ,301 in a first direction X across the top of the frame structure  100 , and a second set of parallel rails  111  arranged perpendicular to the first set of rails  110  to guide movement of the container handling vehicles  201 ,  301  in a second direction Y which is perpendicular to the first direction X. Containers  106  stored in the storage columns  105  are accessed by the container handling vehicles  201 ,  301  through grid openings  115  in the rail system  108 . The container handling vehicles  201 ,  301  can move laterally above the storage columns  105 , i.e. in a plane which is parallel to the horizontal X-Y plane. 
     The upright members  102  of the framework structure  100  may be used to guide the storage containers  106  during raising of the containers out from, and lowering of the containers into, the columns  105 . The stacks  107  of containers  106  are typically self-supportive. 
     Each prior art container handling vehicle  201 ,  301  comprises a vehicle body  201   a ,  301   a , and first and second sets of wheels  201   b ,  301   b ,  201   c ,  301   c  which enable the lateral movement of the container handling vehicles  201 ,  301  in the X direction and in the Y direction, respectively. In  FIGS.  2  and  3    two wheels in each set are fully visible. The first set of wheels  201   b ,  301   b  is arranged to engage with two adjacent rails of the first set  110  of rails, and the second set of wheels  201   c ,  301   c  is arranged to engage with two adjacent rails of the second set  111  of rails. At least one of the sets of wheels  201   b ,  301   b ,  201   c ,  301   c  can be lifted and lowered, so that the first set of wheels  201   b ,  301   b  and/or the second set of wheels  201   c ,  301   c  can be engaged with the respective set of rails  110 ,  111  at any one time. 
     Each prior art container handling vehicle  201 ,  301  also comprises a lifting device  304  for vertical transportation of storage containers  106 , e.g. raising a storage container  106  from, and lowering a storage container  106  into, a storage column  105 . The lifting device  304  comprises one or more gripping / engaging devices (not shown) which are adapted to engage a storage container  106 , and which gripping / engaging devices can be lowered from the vehicle  201 ,  301  so that the position of the gripping / engaging devices with respect to the vehicle  201 ,  301  can be adjusted in a third direction Z which is orthogonal the first direction X and the second direction Y. Parts of the lifting device  304  of the container handling vehicle  301  are shown in  FIG.  3   . The gripping device of the container handling device  201  is located within the vehicle body  201   a  in  FIG.  2   . 
     Conventionally, and also for the purpose of this application, Z=1 identifies the uppermost layer of storage containers, i.e. the layer immediately below the rail system  108 , Z=2 the second layer below the rail system  108 , Z=3 the third layer etc. In the exemplary prior art disclosed in  FIG.  1   , Z=8 identifies the lowermost, bottom layer of storage containers. Similarly, X=1...n and Y=1...n identifies the position of each storage column  105  in the horizontal plane. Consequently, as an example, and using the Cartesian coordinate system X, Y, Z indicated in  FIG.  1   , the storage container identified as  106 ′ in  FIG.  1    can be said to occupy storage position X=10, Y=2, Z=3. The container handling vehicles  201 ,  301  can be said to travel in layer Z=0, and each storage column  105  can be identified by its X and Y coordinates. 
     The possible storage positions within the framework structure / prior art storage grid  100  are referred to as storage cells. Each storage column  105  may be identified by a position in an X- and Y-direction, while each storage cell may be identified by a container number in the X-, Y and Z-direction. 
     Each prior art container handling vehicle  201 ,301 comprises a storage compartment or space for receiving and stowing a storage container  106  when transporting the storage container  106  across the rail system  108 . The storage space may comprise a cavity arranged centrally within the vehicle body  201   a  as shown in  FIG.  2    and as described in e.g. WO2015/193278A1, the contents of which are incorporated herein by reference. 
       FIG.  3    shows an alternative configuration of a container handling vehicle  301  with a cantilever construction. Such a vehicle is described in detail in e.g. NO317366, the contents of which are also incorporated herein by reference. 
     The central cavity container handling vehicles  201  shown in  FIG.  2    may have a footprint that covers an area with dimensions in the X and Y directions which is generally equal to the lateral extent of a storage column  105 , e.g. as is described in WO2015/193278A1, the contents of which are incorporated herein by reference. The term ‘lateral’ used herein may mean ‘horizontal’. 
     Alternatively, the central cavity container handling vehicles  101  may have a footprint which is larger than the lateral area defined by a storage column  105 , e.g. as is disclosed in WO2014/090684A1. 
     The rail system  108  typically comprises rails with grooves in which the wheels of the vehicles run. Alternatively, the rails may comprise upwardly protruding elements, where the wheels of the vehicles comprise flanges to prevent derailing. These grooves and upwardly protruding elements are collectively known as tracks. Each rail may comprise one track, or each rail may comprise two parallel tracks. 
     WO2018146304, the contents of which are incorporated herein by reference, illustrates a typical configuration of rail system  108  comprising rails and parallel tracks in both X and Y directions. 
     In the framework structure / prior art storage grid  100 , a majority of the columns  105  are storage columns  105 , i.e. columns  105  where storage containers  106  are stored in stacks  107 . However, some columns  105  may have other purposes. In  FIG.  1   , columns  119  and  120  are such special-purpose columns used by the container handling vehicles  201 ,  301  to drop off and/or pick up storage containers  106  so that they can be transported to an access station (not shown) where the storage containers  106  can be accessed from outside of the framework structure  100  or transferred out of or into the framework structure  100 . Within the art, such a location is normally referred to as a ‘port’ and the column in which the port is located may be referred to as a ‘port column’  119 ,  120 . The transportation to the access station may be in any direction, that is horizontal, tilted and/or vertical. For example, the storage containers  106  may be placed in a random or dedicated column  105  within the framework structure  100 , then picked up by any container handling vehicle and transported to a port column  119 , 120  for further transportation to an access station. Note that the term ‘tilted’ means transportation of storage containers  106  having a general transportation orientation somewhere between horizontal and vertical. 
     In  FIG.  1   , the first port column  119  may for example be a dedicated drop-off port column where the container handling vehicles  201 ,  301  can drop off storage containers  106  to be transported to an access or a transfer station, and the second port column  120  may be a dedicated pick-up port column where the container handling vehicles  201 ,  301  can pick up storage containers  106  that have been transported from an access or a transfer station. 
     The access station may typically be a picking or a stocking station where product items are removed from or positioned into the storage containers  106 . In a picking or a stocking station, the storage containers  106  are normally not removed from the automated storage and retrieval system  1 , but are returned into the framework structure  100  again once accessed. A port can also be used for transferring storage containers to another storage facility (e.g. to another framework structure or to another automated storage and retrieval system), to a transport vehicle (e.g. a train or a lorry), or to a production facility. 
     A conveyor system comprising conveyors is normally employed to transport the storage containers between the port columns  119 ,  120  and the access station. 
     If the port columns  119 ,  120  and the access station are located at different levels, the conveyor system may comprise a lift device with a vertical component for transporting the storage containers  106  vertically between the port column  119 ,  120  and the access station. 
     The conveyor system may be arranged to transfer storage containers  106  between different framework structures, e.g. as is described in WO2014/075937A1, the contents of which are incorporated herein by reference. 
     When a storage container  106  stored in one of the columns  105  disclosed in  FIG.  1    is to be accessed, one of the container handling vehicles  201 ,  301  is instructed to retrieve the target storage container  106  from its position and transport it to the drop-off port column  119 . This operation involves moving the container handling vehicle  201 ,  301  to a location above the storage column  105  in which the target storage container  106  is positioned, retrieving the storage container  106  from the storage column  105  using the container handling vehicle’s  201 ,  301  lifting device  304 , and transporting the storage container  106  to the drop-off port column  119 . If the target storage container  106  is located deep within a stack  107 , i.e. with one or a plurality of other storage containers  106  positioned above the target storage container  106 , the operation also involves temporarily moving the above-positioned storage containers prior to lifting the target storage container  106  from the storage column  105 . This step, which is sometimes referred to as “digging” within the art, may be performed with the same container handling vehicle that is subsequently used for transporting the target storage container to the drop-off port column  119 , or with one or a plurality of other cooperating container handling vehicles. Alternatively, or in addition, the automated storage and retrieval system  1  may have container handling vehicles specifically dedicated to the task of temporarily removing storage containers from a storage column  105 . Once the target storage container  106  has been removed from the storage column  105 , the temporarily removed storage containers can be repositioned into the original storage column  105 . However, the removed storage containers may alternatively be relocated to other storage columns. 
     When a storage container  106  is to be stored in one of the columns  105 , one of the container handling vehicles  201 ,  301  is instructed to pick up the storage container  106  from the pick-up port column  120  and transport it to a location above the storage column  105  where it is to be stored. After any storage containers positioned at or above the target position within the storage column stack  107  have been removed, the container handling vehicle  201 ,  301  positions the storage container  106  at the desired position. The removed storage containers may then be lowered back into the storage column  105 , or relocated to other storage columns. 
     For monitoring and controlling the automated storage and retrieval system  1 , e.g. monitoring and controlling the location of respective storage containers  106  within the framework structure  100 , the content of each storage container  106 ; and the movement of the container handling vehicles  201 ,  301  so that a desired storage container  106  can be delivered to the desired location at the desired time without the container handling vehicles  201 ,  301  colliding with each other, the automated storage and retrieval system  1  comprises a control system  500  which typically is computerized and which typically comprises a database for keeping track of the storage containers  106 . 
       FIG.  4    shows examples of product items  80  stored in a storage container  106  having height H f , a width W f  and a length L f   
     For systems containing a large number of bins in each stack, the above mentioned ‘digging’ may prove both time and space consuming when the target bin is located deep within the grid. For example, if the target bin has location Z=5, the vehicle(s) must lift four non-target bins and place them in other positions, often on top of the grid (Z=0), before the target bin can be reached. Before being replaced back into the grid, the non-target bins may force other robots to choose non-optimized paths to execute their respective operations. 
     An objective of the present invention is therefore to provide a storage grid and a storage and retrieval system using such a storage grid which may provide a more time efficient storage and retrieval method compared to prior art systems, for example a more time efficient delivery of product items to a customer / end-user. 
     Another objective, at least in preferred embodiments, is to provide a solution where the picking process is performed by remotely operated vehicles without any kind of time consuming digging operations. 
     Yet another objective is to provide a storage and retrieval system in which the time efficiency of storing and retrieving product items can be selected by the user depending on urgency and/or priority. 
     Yet another objective is to provide a storage and retrieval system combining storage capacity with time efficient delivery of product items to a customer. 
     Yet another objective is to provide a storage grid and a storage and retrieval system using such a storage grid which may provide a high throughput of product items, such as product items on sale. 
     SUMMARY OF THE INVENTION 
     The invention is set forth in the independent claims and the dependent claims describe certain optional features of the invention. 
     In particular, the invention concerns a storage grid for storing storage containers. The storage grid comprises a plurality of horizontal container supporting frameworks distributed vertically with vertical offsets. 
     The plurality of horizontal container supporting frameworks comprise a first horizontal container supporting framework and at least one second container supporting framework arranged beneath and parallel to the first container supporting framework. 
     Each of the first and the at least one second container supporting frameworks comprises one or more container supports configured / designed to support a plurality of storage containers. If several, the container supports are preferably arranged in parallel along a first direction (X), i.e. with their sides extending in a second direction (Y) arranged side-by-side with offset. 
     The container support(s) may be elongated with its/their elongated direction in the second direction (Y). Alternatively, it/they may be squared with principal directions in the first and second directions (X,Y). In yet an alternative design, the container support(s) may have the shape of a toroid or a plurality of coaxially arranged toroids. 
     The storage containers are distributed one-by-one on the container support(s) within each container supporting framework. In case of an elongated or squared container supports, the storage containers are distributed one-by-one in line along at least the second direction (Y). In case of a toroid shaped container supports, the storage containers may be distributed one-by-one following the curve of the toroid(s). 
     Each container support displays at least one hole with an opening size being at least a maximum horizontal cross section of the storage containers to be stored. Furthermore, the storage grid is designed such that the at least one hole of the first container supporting framework are aligned vertically, i.e. with equal position in the first and second directions (X,Y), with the at least one hole of the at least one second container supporting framework. 
     At least one of the container support(s) of the at least one second container supporting framework, preferably at least two, and most preferably all, is/are displaceable along a second direction (Y) orthogonal to the first direction (X) in case of an elongated or squared container support, or around a center axis of the toroid(s) in case of toroid shaped container support(s). At least one of the container support(s) of the first container supporting framework may also be similarly displaceable. 
     A storage grid comprises a combination of elongated/squared shaped container supports and toroid shaped container supports may also be envisaged. 
     In an exemplary configuration, the storage grid further comprises a support displacement device configured to displace at least one, and preferably all, of the plurality of displaceable container supports. The support displacement device can for example be a linear actuator, gearwheel drive, or the like. The support displacement device may be motorized and/or may be mechanically, hydraulically, pneumatically and/or electrically operated. 
     In yet another exemplary configuration, the storage grid further comprises a control system configured to remotely operate the support displacement device such that the displaceable container support may be moved remotely. Or, in case of a plurality of displaceable container supports, each of the displaceable container supports may be moved remotely and independently to the other displaceable container supports within their respective container supporting framework. 
     In yet another exemplary configuration, the container support(s) displays a plurality of holes distributed evenly along the second direction (Y). However, any distribution of holes along the second direction (Y) may be envisaged, for example that the plurality of holes are distributed on either sides of four storage container spaces, then three spaces, then two, etc. The latter may have the advantage of offering different access rates for different type of stocks. 
     In yet another exemplary configuration, the first container supporting framework and the at least one second container supporting framework have equal or near equal horizontal extent. 
     In yet another exemplary configuration, the storage grid further comprises a rail system arranged above and adjacent to the first container supporting framework at a first vertical offset V rl  being at least a maximum height of the storage containers to be stored. Said rail system may comprise a first set of parallel rails arranged in a horizontal rail system plane (P rs ) and extending in the first direction (X) and a second set of parallel rails arranged in the horizontal plane (P rs ) and extending in the second direction (Y). The first and second sets of rails form a grid pattern in the horizontal plane (P rs ) comprising a plurality of adjacent grid cells, wherein each of the grid cells comprises a grid opening defined by a pair of adj acent rails of the first set of rails and a pair of adjacent rails of the second set of rails. 
     In yet another exemplary configuration, the container supports are either elongated or squared, where each of them has a length corresponding to the length of a plurality of grid cells in the second direction (Y). In one specific example, the width of the container supports is such that only one storage container may be supported along the first direction (X). 
     In yet another exemplary configuration, the rail system, the first container supporting framework and the at least one second container supporting framework have equal or near equal horizontal extents. 
     In yet another exemplary configuration, the plurality of horizontal container supporting frameworks comprise a number of i parallel container supporting frameworks in the horizontal plane (P rs ), where i is an integer of 2 or more, more preferably 3 or more, even more preferably 4 or more. Further, the i parallel container supporting frameworks are arranged at a distance dV = i*ΔdV below a lower edge of the rail system, where ΔdV is a constant that is set equal or higher than a maximum height of the storage container ( 106 ) to be stored. Alternatively, i-1 parallel container supporting frameworks are arranged at a distance dV = (i-1)* ΔdV below a lower edge of the first container supporting framework, while the distance V rl  between the lower edge of the rail system and the lower edge of the first supporting framework is different from ΔdV, for example larger. 
     In yet another exemplary configuration, one or more of the container supporting frameworks is/are arranged at a distance below a lower edge of an above adjacent rail system and/or a lower edge of an above adjacent container supporting framework, corresponding to a height that is equal or higher than a maximum height of a stack of several storage containers 
     In yet another exemplary configuration, each of the plurality of displaceable container supports displays a plurality of holes distributed with an offset corresponding to 2n+1 grid cells along the second direction (Y), where n is an integer of 1 or more. 
     In yet another exemplary configuration, each of the plurality of displaceable container supports displays a plurality of holes distributed with an offset corresponding to n+1 grid cells along the second direction (Y), where n is an integer of 1 or more. 
     In yet another exemplary configuration, the displaceable container support is displaceable a distance corresponding to at least the distance of n grid cells in the second direction (± Y), where n is an integer of 1 or more. In case of a plurality of displaceable container supports, each may be individually displaceable a distance corresponding to at least the distance of n grid cells. 
     The invention also concerns an automated storage and retrieval system configured to store a plurality of storage containers. The system comprises a storage grid as described above, a plurality of storage containers supported, and distributed horizontally one-by-on, on the plurality of horizontally arranged container supporting frameworks, one or more remotely operated vehicles configured to move laterally / horizontally in the first direction (X) and the second direction (Y) above the plurality of container supporting frameworks, wherein the remotely operated vehicle(s) comprises a lifting device configured to grab and lift a storage container and a control system configured to monitor and control wirelessly movements of the remotely operated vehicle(s). 
     In an exemplary configuration, the remotely operated vehicle(s) may be a travelling crane system comprising a bar movably supported at its ends on two opposite peripheral sides of the storage grid along one of the first and second directions (X,Y) and a crane with a lifting device as described above, movably arranged onto the bar. The movement along the bar ensures movement in the other direction (Y,X) and can be achieved by sliding or rolling. The movement of the bar along the peripheral sides of the storage grid and/or the movement of the crane along the bar may be achieved by any known displacement device such as an arrangement using drive gear. The displacement device may be identical to the support displacement device used to displace the container supports as described above. 
     In another exemplary configuration, the storage grid comprises a rail system as described above. In this particular configuration the storage containers are supported on the horizontally arranged container supporting frameworks in such a way that each storage container is positioned directly below a grid opening of the rail system. Furthermore, the remotely operated vehicle is configured to move laterally in the first direction (X) and the second direction (Y) on the rail system and to lift the storage container through the grid opening by use of the lifting device. 
     In yet another exemplary configuration, the automated storage and retrieval system may further comprise a second storage grid comprising a second rail system comprising a first set of parallel rails arranged in the horizontal rail system plane (P rS ) and extending in a first direction (X) and a second set of parallel rails arranged in the horizontal rail system plane (P rs ) and extending in a second direction (Y) which is orthogonal to the first direction (X). The first and second sets of rails form a grid pattern in the horizontal plane (P rs ) comprising a plurality of adjacent grid cells, wherein each of the grid cells comprises a grid opening defined by a pair of adjacent rails of the first set of rails and a pair of adjacent rails of the second set of rails. 
     The second storage grid further comprises a plurality of stacks of storage containers arranged in storage columns located beneath the second rail system, wherein each storage column is located vertically below a grid opening. 
     In this exemplary configuration, the remotely operated vehicle(s) operable on the inventive storage grid is/are configured to also move laterally (in the horizontal plane P rs ) on the second rail system. 
     In yet another exemplary configuration, the system further comprises a coupling rail system comprising rails extending in at least one of the first direction (X) and the second direction (Y) and configured such the remotely operated vehicle(s) may move between the rail system of the inventive storage grid and the second rail system of the second storage grid. For example, the coupling rail system may be identical to a part of the rail system of the inventive storage grid and/or a part of the rail system of the second storage grid, wherein the rails of the coupling rail system oriented in the first or second direction (X,Y) are aligned with the rails of the two rail systems in the same direction. 
     In yet another exemplary configuration, the width of the rails in at least one of the first and second directions (X,Y) of the rail system forming part of the inventive storage grid is larger than the width of the rails in the same direction(s) of the rail system forming part of the second storage grid. 
     By combining the prior art grid and the inventive grid as described above, a storage system is achieved that may combine a time efficient storage and retrieval storage grid with a high storage capacity storage gird. The product items can thereby be arranged according to their needed / preferred turnover. 
     For example, the storage container with the product items can be picked from the prior art high storage capacity storage grid and stored (buffered) intermediately into the inventive time efficient storage grid. The product items may be items that needs to be swiftly available such as preordered items and/or campaign (sale) items. The storage (buffering) in the inventive storage grid renders time efficient delivery of product items to the customer possible at arrival. 
     The invention also concerns a method for storing and retrieving storage containers from an automated storage and retrieval system as disclosed above. 
     The plurality of horizontal container supporting frameworks comprises a number of i parallel container supporting frameworks, where i is an integer of 2 or more. Further, all i parallel container supporting frameworks displays at least one hole, and each of the at least i-1 parallel container supporting frameworks beneath the first (topmost) framework comprises at least one, preferably at least two, container support(s) / supporting track(s) being displaceable along the second direction (Y). 
     The method comprises the following steps:
     A. moving the remotely operated vehicle(s) to a position where its/their lifting device is positioned in vertical alignment above either a target storage container supported on the first container supporting framework or, if the target storage container is situated on one of the i-1 parallel container support frameworks in vertical alignment (i.e. the same position in the first and second directions (XY)) beneath the first container supporting framework, a target hole of the first container supporting framework located horizontally closest to the target storage container,   B. if the target storage container is not positioned in vertical alignment below the target hole,
   a) displacing the displaceable container support of the supporting framework onto which the target storage container is supported in the second direction (Y) to position the target storage container in vertical alignment below the target hole of the first container supporting framework or   b) if also at least one, preferably at least two, of the plurality of container supports of the first container supporting framework are displaceable along the second direction (Y), displacing displaceable container support(s) of the container support framework(s) situated above the target storage container supporting displaceable container support, where one of the displaceable container support(s) of each of the above situated container supporting framework(s) has the same position in the first direction (X) as the target storage container supporting displaceable container support, a distance in the second direction (Y) opposite the direction in a), to position the target storage container in vertical alignment below the target hole of the first container supporting framework or   c) if at least one, preferably at least two, of the plurality of container supports ( 402   a - d ) of the first container supporting framework ( 401   a ) are displaceable along the second direction (Y), displacing both the target storage container supporting displaceable container support as described in step a) and the above situated displaceable container support(s) as described in step b) to position the target storage container in vertical alignment below the target hole,   
   C. lowering, grabbing and lifting the target storage container by use of the lifting device, e.g. through a grid opening, and   D. moving the remotely operated vehicle(s) with the target storage container to another horizontal location on top of the storage grid.   

     Note that, for step B, part step b), since all holes are initially in vertical alignment (same position in first and second directions (X,Y), placing the container support with the target hole of the first container supporting framework vertically aligned with the target storage container result in the vehicle has an unobstructed, vertical, access to the target storage container. 
     In an exemplary process, the storage grid used in the method further comprises a rail system as described above, wherein the plurality of storage containers are supported on the plurality of horizontally arranged container supporting frameworks such that each storage container is positioned directly below a grid opening of the rail system. Furthermore, the remotely operated vehicle(s) is/are configured to move laterally in the first direction (X) and the second direction (Y) on the rail system and to lift the storage container through the grid opening by use of the lifting device. As an alternative to remotely operated vehicle(s) operating on such a rail system, the method may use a system of transverse cranes as described above. 
     In another exemplary process, the automated storage and retrieval system further comprises a second rail system of a second storage grid, a rail system of an inventive storage grid and a coupling rail system as described above, wherein the remotely operated vehicle(s) moves between the rail system and the second rail system during at least one of step A and step D. 
     The invention also concerns use of an automated storage and retrieval system as disclosed above for delivering items arranged within the storage containers stored in the storage grid to end users, for example by use of conveyor belts transporting the storage containers, or dedicated delivery containers initially stored within the storage containers, from the storage grid to a location for loading onto delivery trucks and/or directly to customer / end users. The system may for example be used in a retail shop for swift delivery of items to customers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings depict alternatives of the present invention and are appended to facilitate the understanding of the invention. However, the features disclosed in the drawings are for illustrative purposes only and shall not be interpreted in a limiting sense. 
         FIG.  1    is a perspective view of a prior art automated storage and retrieval system. 
         FIG.  2    is a perspective view of a prior art container handling vehicle having a centrally arranged cavity for carrying storage containers therein. 
         FIG.  3    is a perspective view of a prior art container handling vehicle having a cantilever for carrying storage containers underneath. 
         FIG.  4    is a perspective view of a storage container and product items stored in the storage container. 
         FIG.  5    is a side view of a storage system in accordance with one embodiment of the invention, where  FIG.  5 A  shows the storage system with a target storage container in an initial position, a vacant storage cell for a storage container in an initial position and a remotely operated vehicle carrying a storage container,  FIG.  5 B  shows the storage system with the vacant storage cell in a position ready to receive the storage container from the remotely operated vehicle,  FIG.  5 C  shows the storage system where the storage container is placed in the previously vacant storage cell and a lifting device of the remotely operated vehicle is retracted above the container supporting framework of the target storage container,  FIG.  5 D  shows the storage system with the remotely operated vehicle ready to lift the target storage container and  FIG.  5 E  shows the storage system with the target storage container in a position ready to be lifted. 
         FIG.  6    is a top view of a storage system in accordance with the storage system of  FIG.  5   . 
         FIG.  7    is a top view of a storage system in accordance with a second embodiment of the invention. 
         FIG.  8    is a top view of a storage system in accordance with a third embodiment of the invention. 
         FIG.  9    is a perspective side view of a storage system in accordance with a fourth embodiment of the invention. 
         FIG.  10    are perspective views of a container support forming part of an embodiment of the invention, where  FIG.  10 A  and  FIG.  10 B  show the container support in an isometric view and along one end, respectively. 
         FIG.  11    is a perspective view of a linear activator for displacing the container support shown in  FIG.  10   . 
         FIG.  12    is a perspective view of container supports mounted in a framework forming part of an embodiment of the invention. 
         FIG.  13    is a perspective view of part of the framework shown in  FIG.  12   . 
         FIG.  14    is a perspective top view of a storage system according to a fourth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the following, different alternatives will be discussed in more detail with reference to the appended drawings. It should be understood, however, that the drawings are not intended to limit the scope of the invention to the subject-matter depicted in the drawings. Furthermore, even if some of the features are described in relation to the system only, it is apparent that they are valid for the methods as well, and vice versa. 
     With particular reference to  FIG.  5   ,  FIG.  6    and  FIG.  14   , the inventive storage and retrieval system  1  comprises remotely operated vehicles  301  operating on a rail system  408  comprising a first set of parallel rails  410  arranged to guide movements of the remotely operated vehicles  301  in a first direction X across a storage grid  400  and a second set of parallel rails  411  arranged perpendicular to the first set of rails  410  to guide movement of the remotely operated vehicles  301  in a second direction Y which is perpendicular to the first direction X. The storage containers  106  stored within the storage grid  400  are accessed by the remotely operated vehicles  301  through grid openings  415  in the rail system  408 . Each grid opening  415  of the rail system  408  is enclosed by a grid cell  422 . The rail system  408  extends in a horizontal plane Prs. 
     As best seen in  FIG.  5   , the storage containers  106  are stored on a plurality of frameworks  401  distributed in a Z direction below the rail system  408  with a vertical offset indicated by V r1  (i.e. the offset between the lower edge of the rail system  408  and the lower edge for the first framework  401   a  directly beneath the rail system  408 ) and a vertical offset indicated by ΔdV (i.e. the average offset between the lower edges of the adjacent deeper laying frameworks  401   b - h ). 
     The vertical offsets V rl  and ΔdV may be selected to provide a height that is equal or higher than a maximum height of one storage container  106  or a stack  107  of several storage containers  106 . As an example, the first framework  401   a  may be adapted to store stacks  107  of storage containers  106  while the below situated frameworks  401   b - k  may be adapted to store single (unstacked) storage containers  106 . As a further example, several or all frameworks  401  of the grid  400  may be adapted to store stacks  107  of several storage containers  106 . The different frameworks  401  of the same grid  400  may be configured to store stacks  107  of unequal numbers of storage containers  106 . The vertical space (i.e. the available height) required for one or several frameworks  401  of the grid  400  to be adapted to store a stack  107  of several storage containers  106  may be obtained by reducing the total number of frameworks  401  as compared to a configuration of the grid  400  where all frameworks  401  are adapted to store single (unstacked) storage containers  106 . FIGS.  5 A-E  show vertical cross-sections of the storage system  400 . 
     In 5A, a target storage container  106 ′ and a vacant storage space  106 ″ are located in different container supporting frameworks  401   e ,  401   g . The remotely operated vehicle  301  approaching to pick the target storage container  106 ′ typically brings another storage container  106  that is to be stored in the storage system  400 . Before the remotely operated vehicle  301  can pick the target storage container  106 ′, the vehicle held storage container  106  is advantageously placed in a vacant storage space  106 ″ within the storage grid  400  (a process typically referred to as an exchange process). 
     By having less storage containers  106  than there are available container spaces within the storage system  400 , there will always be at least one vacant storage space  106 ″. Vacant storage spaces  106 ″ will also be dynamically generated as remotely operated vehicles  301  pick storage containers  106  from within the storage grid  400 . If there are no vacant storage spaces  106 ″ in the storage system  400 , the remotely operated vehicle  400  must either refrain from bringing another storage container  106  from for example the port column  119 ,  120  or place the held storage container  106  on top of the storage grid  400 . Both alternatives suffers disadvantages in respect of time efficiency. 
       FIG.  5 B  shows the storage system  1  with the vacant storage space  106 ″ in a position ready to receive the storage container  106  from the remotely operated vehicle  301 . The vacant storage space  106 ″ (into which the storage container  106  is to be placed) and the target storage container  106 ′ are preferably horizontally closest to the same hole target  403   b ′. In this way the remotely operated vehicle  301  does not need to move between the two operations during the same exchange process. Even more preferred, in addition to being available through the same target hole  403   b ′, the vacant storage space  106 ″ and the target storage container  106 ′ can be located on the same container support  402  (not shown in  FIG.  5   ). In this way the remotely operated vehicle  301  can have a minimum movement of its lifting device  304  between the two operations of the exchange process. Thus, the exchange process time will not be prolonged due to conflicting displacements of the lifting device  304  and the container support  402  of the target storage container  106 ′. 
       FIG.  5 C  shows the storage system  1  where the storage container  106  earlier held by the vehicle  301  has been received within the previously vacant storage space  106 ″. Further, the lifting device  304  has been retracted vertically above the container supporting framework  401   e  of the target storage container  106 ′. Consequently, the lifting device  304  has been sufficiently retracted so that displacement of the container support  402   a  of the target storage container  106 ′ can start and continue until the target storage container  106 ′ is situated beneath the target hole(s)  403   b ′. If the lifting device  304  is retracted higher than just above the container supporting framework  401   e  of the target storage container  106 ′, the exchange process would become less time efficient. 
     In  FIGS.  5 A-B , the target storage container  106 ′ is located higher within the storage system  400  than the vacant storage space  106 ″. In the opposite case, the container support  402  of the previously vacant storage space  106 ″ must retract to its initial position after having completed its displacement of the target storage container  106 ′ to the target hole  403 ′ in order for the lifting device  304  to get access to lower situated container supporting frameworks  401 . 
       FIG.  5 D  shows the storage system  1  with the remotely operated vehicle  301  ready to lift the target storage container  106 ′ after placing the formerly held storage container  106  into the vacant storage space  106 ″, i.e. with its lifting device  304  just above the framework  401   e  supporting the target storage container  106 ′. The container support  402   a  of the previously vacant storage space  106 ″, now occupied by the storage container  106 , has been displaced back to its initial position. Displacement of the container support  402   a  of the target storage container  106 ′ may now start to place the target storage container  106 ′ beneath the target hole(s)  403   b ′. 
       FIG.  5 E  shows the storage system  1  with the target storage container  106 ′ presented beneath the target hole(s)  403   b ′, i.e. in a position ready to be lifted by the lifting device  304  of the vehicle  301 . 
     After the target storage container  106 ′ has been lifted above the container supporting framework  401   e , the container support  402   a  can be displaced back to its initial position. 
     For the specific embodiment depicted in  FIGS.  5  and  6   , each of the frameworks  401   a - k  comprises several elongated container support  402   a - d  having their longitudinal orientation in the Y direction and arranged parallel to each other in the X direction. The container supports  402   a - d  in each framework  401   a - k  displays holes  403   a - f  distributed along the Y direction, where each hole  403   a - c  has a cross sectional being at least the cross-sectional area of a storage container  106 , i.e. at least Wf x Lf (see  FIG.  4   ). The storage containers  106  are placed on top of support plates  404  between these holes  403   a - c . Each storage container  106  is stabilized in the horizontal plane Prs by first stabilization ribs  405  along the X direction and second stabilization ribs  406  along the Y direction. The first stabilization ribs  405  protrude upwards from both X directed sides of each of the support plates  404 , thereby preventing each storage container  106  to move along the Y direction relative to the container support  402   b . Further, the second stabilization ribs  406  extend along the full length of the container support  402   b  in the Y direction having a part that protrudes above the support plates  404 , thereby preventing each storage container  106  to move in the X direction relative to the container support  402   b . 
     An example of such a container support design is shown in  FIG.  10   . The container support  402   b  has an elongated shape extending in the Y direction and a width in the X direction allowing one storage container  106  having with W f.  Each storage container  106  is constrained in X and Y directions by the above-mentioned stabilization frames  405 ,406. The container support  402   b  displays a hole  403   a - f  along the Y direction after each third storage container space, wherein each of the holes  403   a - f  has a width and length in the X and Y directions, respectively, being approximately the width (W f ) and length (L f ) of the storage container  106 . In this particular confirmation of the container supports  402   b , a storage container guiding structure  409  in form of a bottomless box is fixed along the peripherals of each hole  403   a - f  in order to aid the storage container to be guiding correctly through the hole  403   a - f  during lifting / lowering by the respective vehicles  301 . 
     Each sides of the support plates  404  are fastened by brackets  407  onto the second stabilization ribs  406 . 
     In order to store and retrieve a target storage container 106′ using the above described embodiment, the following operations are performed, with particular reference to  FIGS.  5 D and E :
     The control system  500  gives instructions to the vehicle  301  to pick up a target storage container  106 ′ with coordinates X,Y,Z. This position corresponds to a storage container  106  supported on a support plate  404  of a container support  402   a  forming part of a horizontal container support framework  401   e  at a depth of 3xΔdV+Vrl below the rail system  408 . The target storage container  106  is separated in the Y direction to a nearest hole  403   b ′ (i.e. the target hole) by one non-target storage container  106 . Since all the holes in the storage grid  400  are initially aligned (with same X-Y coordinates), the X-Y position of the target hole  403   b ′ of the container support framework  401   a  adjacent the rail system  408  is equal to the X-Y positions of the target holes  403   b ′ of the underlying container support frameworks  401   b - h .   The vehicle  301  moves by aid of its drive means  301   b ,c in the X and Y directions until its lifting device  304  is located directly above the target hole  403   b ′ situated closest in horizontal direction to the target storage container  106 ′.   During and/or after movement of the vehicle  301  to the position above the target hole  403   b ′, the control system  500  sends an instruction to a support displacement device  700  (see  FIG.  11   ) to displace the container support  402   a  of the container framework  401   e  a sufficient distance in the Y direction so that the target storage container  106 ′ is vertically aligned with the target holes  403   b ′ of the above situated container frameworks  401   a - d .   During and/or after the displacement of the container support  402   a , the lifting device  304  of the vehicle  301  is activated and lowered down through the grip opening  415  and the aligned target holes  403   b ′ until the gripping part of the lifting device  304  is in position to grip the target storage container  106 .   After the target storage container  106 ′ has been gripped by the lifting device  304  and lifted above the above situated container framework  401   d , the support displacement device  700  is again activated in order to move the container support  402   a  back to its initial Y position.   When the target storage container  106 ′ has been lifted above the rail system  408 , the vehicle  301  is moved to another location on the rail system  408 , for example to a dedicated port column / chute  436  for delivery to an access station  436 .   

     The process has the advantage that the need for digging performed for prior art storage and retrieval system is no longer necessary. 
       FIG.  7    and  FIG.  8    show another embodiment of the inventive system  1 , where the inventive storage grid  400  is placed adjacent to a prior art storage grid  100 . The prior second storage grid  100  is constructed in accordance with the storage grid  100  described above in connection with  FIGS.  1 - 3   , i.e. a number of upright members  102  and a number of horizontal members  103 , which are supported by the upright members  102 , and further that the second storage grid  100  comprises a rail system  108  in the X direction and Y direction. The prior art storage grid  100  further comprises storage compartments in the form of storage columns  105  provided between the members  102 ,  103 , where storage containers  106  are stackable in stacks  107  within the storage columns  105 . 
     Both the inventive storage grid and the prior art storage grid  100  can be of any size. In particular it is understood that the one or both of the storage grids  100 , 400  can be considerably wider and/or longer and/or deeper than disclosed in the accompanied figures. For example, the storage grids  100 , 400  may have a horizontal extent having space for more than 700×700 storage containers  106  and a storage depth of more than twelve storage containers  106 . 
     In  FIG.  7    an inventive storage grid  400  of size corresponding to 4 times 15 grid cells  422  of its respective rail system  408  is placed with one vertical side extending in the Y direction along a vertical side of a prior art storage grid  100  of size corresponding to 5 times  17  grid cells  122  of its respective rail system  108 . The rail system  408  of the inventive storage grid  400  and the rail system  108  of the prior art storage grid  100  have a mutual orientation and design such that the same type of vehicles  301  may operate on both rail systems  108 ,  408 . 
     Again, with reference to  FIG.  14   , a possible coupling of the two rail systems  108 ,  408  is shown that allows the same type of vehicles  301  to move between the two storage grids  100 ,  400 . In the particular configuration of  FIG.  14   , the desired coupling is achieved by an intermediate coupling rail system  408 ′ extending in the X direction. Due to the different construction of the container frameworks  401  for the inventive storage grid  400  and the stacks  107  of storage containers  106  for the prior art storage grid  100 , the rails  410 ,  411  above the container frameworks  401  can with advantage be made wider compared to the rails  110 ,  111  above the stacks  107 , at least in one of the X-Y directions. 
     As shown in  FIG.  7   , the different container supports  402   a - d  may be moved a distance in the Y-direction corresponding to two grid cells by use of the displacement device  700 . 
     An example of a displacement device  700  is shown in  FIG.  11    and  FIG.  12   . The displacement of each container support  402   a - d  is achieved by a mechanical linear actuator (ball screw) that translates rotational motion to linear motion. A threaded shaft  702  provides a helical raceway for ball bearings which act as a precision screw. The required rotation of the shaft is achieved by an electric motor  701  connected to one of the shaft’s end. A stopper  705  is fixed to the opposite end of the shaft  702 . Furthermore, a slider  703  is coupled to the rotational shaft such that it moves along the shaft  702  during rotation. By attaching the slider  703  to the end of the container support  402   a - d , the desired displacement in the Y direction is achieved. The shown linear actuator  700  is fastened to a skeleton structure comprising a plurality of towers  430  having a height corresponding to the height of the storage grid excluding the rail system  408  and a horizontal extent corresponding to n × m storage container spaces, where n and m are integers of  1  or more.  FIG.  13    shows an example of such a tower  430  of horizontal size 1×1. The tower  430  comprises horizontal frameworks for each vertical level of the container framework  401  set up by two rods  432  in the X direction for structural rigidity and two vertical plates  433  in the Y direction. A container support wheel  434  is rotationally fastened to the face facing inwards of both vertical plates  433 . The two rods  432  and the two vertical plates  433  are fastened in rectangular form to  4  or more vertical pillars  431 . The tower  430  itself is supported on the floor  440  by tower supports  435 . 
     As best seen in  FIG.  12   , each container support  402  is arranged inside a row of towers  430  oriented in the Y direction. Due to the container support wheels  434 , the container supports  402  may easily be displaced. The linear actuator  700  is connected to the skeleton structure of towers  430  by fixing a linear actuator support  704  between the rod  432  of the outermost tower  430  and the rod  432  of the adjacent tower  430 . Further, the stopper  705  at the end distal to the electric motor  701  is fixed at a rod  432  further into the skeleton structure (for example a length corresponding to three adjacent storage container spaces as depicted in  FIG.  12   ). The end of the container support  402  is connected to the slider  703  movable along the shaft  702 , thereby render possible the desired displacement in the Y direction. Note that the container support  402  has been removed from the lowermost part of the skeleton structure to better illustrate the details. 
       FIG.  8    shows another configuration of the storage and retrieval system  1  comprising one prior art storage grid  100  and three inventive storage grids  400  arranged on the sides of the prior art storage grid  100  along the Y direction. The container supports  402 ,  402   a - d  of each inventive storage grids  400  may be displaced in the Y direction a length corresponding to two adjacent storage container spaces (both ways). The holes  403   a - c  are distributed along the Y direction with a distance between corresponding to four adjacent storage container spaces. As described above for the configuration shown in  FIGS.  6  and  7   , the rail system  408  of the inventive storage grid  400  and the rail system  108  of the prior art storage grid  100  are mutually configured such as the same type of vehicle  301  may move between all storage grids  100 ,  400  without human interference. 
       FIG.  9    shows a perspective view of a configuration of a storage and retrieval system  1  which is similar to the configuration shown in  FIG.  8   , but with one inventive storage grid  400  and several prior art storage grids  100 . The above-mentioned linear actuators  700  acting as the displacement device is shown arranged at the end of each container support  402 . This particular configuration comprises eleven container supporting frameworks  401   a - k  arranged beneath a rail system  408 , each with three container supports  402   a - c  displaceable in the Y direction. In order to render movement between the different storage grids  100 ,  400 , a coupling rail system  408 ′ is seen interconnecting the rail system  108  of the prior art storage grids  100  and the rail system  408  of the inventive storage grid  400 . See also  FIG.  14   . 
     One way of installing the storage grid  400  as described above can be to remove all stacks of storage containers beneath a rail system of part of a prior art storage and retrieval system  1  as shown in  FIG.  1   , and inserting one or more inventive storage grids  400  within the empty volume. 
     In the preceding description, various aspects of the automated storage and retrieval system and associated method of picking product items using vehicles have been described with reference to the illustrative embodiment. For purposes of explanation, specific numbers, systems and configurations were set forth in order to provide a thorough understanding of the system and its workings. However, this description is not intended to be construed in a limiting sense. Various modifications and variations of the illustrative embodiment, as well as other embodiments of the system, which are apparent to persons skilled in the art to which the disclosed subject matter pertains, are deemed to lie within the scope of the present invention. 
     
       
         
           
               
               
             
               
                 Reference Numerals 
               
             
            
               
                 
                   1 
                 
                 Storage and retrieval system 
               
               
                 
                   80 
                 
                 Product items 
               
               
                 
                   100 
                 
                 Framework structure / prior art storage grid / second storage grid 
               
               
                 
                   102 
                 
                 Upright members of framework structure 
               
               
                 
                   103 
                 
                 Horizontal members of framework structure 
               
               
                 
                   105 
                 
                 Storage column 
               
               
                 
                   106 
                 
                 Storage container 
               
               
                   106 ′ 
                 Particular position of a storage container / target storage container 
               
               
                   106 ″ 
                 Vacant storage space for a storage container 
               
               
                 
                   107 
                 
                 Stack 
               
               
                 
                   108 
                 
                 Prior art rail system 
               
               
                 
                   110 
                 
                 Parallel rails in first direction (X) 
               
               
                 
                   110 
                   a 
                 
                 First rail in first direction (X) 
               
               
                 
                   110 
                   b 
                 
                 Second rail in first direction (X) 
               
               
                 
                   111 
                 
                 Parallel rail in second direction (Y) 
               
               
                 
                   111 
                   a 
                 
                 First rail of second direction (Y) 
               
               
                 
                   111 
                   b 
                 
                 Second rail of second direction (Y) 
               
               
                 
                   115 
                 
                 Grid opening 
               
               
                 
                   119 
                 
                 First port column 
               
               
                 
                   120 
                 
                 Second port column 
               
               
                 
                   201 
                 
                 Prior art storage container vehicle 
               
               
                 
                   201 
                   a 
                 
                 Vehicle body of the storage container vehicle  101 
 
               
               
                 
                   201 
                   b 
                 
                 Drive means / wheel arrangement, first direction (X) 
               
               
                 
                   201 
                   c 
                 
                 Drive means / wheel arrangement, second direction (Y) 
               
               
                 
                   301 
                 
                 Prior art cantilever storage container vehicle / remotely operated vehicle 
               
               
                 
                   301 
                   a 
                 
                 Vehicle body of the vehicle  301 
 
               
               
                 
                   301 
                   b 
                 
                 Drive means in first direction (X) 
               
               
                 
                   301 
                   c 
                 
                 Drive means in second direction (Y) 
               
               
                 
                   304 
                 
                 Lifting device 
               
               
                 
                   400 
                 
                 Storage system 
               
               
                 
                   401 
                 
                 Horizontal container supporting framework 
               
               
                 
                   401 
                   a 
                 
                 First container supporting framework 
               
               
                   401   b - k   
                 Second / underlying container supporting framework(s) 
               
               
                   402 ,  402   a - d   
                 Container support 
               
               
                   403 ,  403   a - f   
                 Hole (in container support  402 ) 
               
               
                   403   b ′ 
                 Target hole 
               
               
                 
                   404 
                 
                 Support plate for storage container 
               
               
                 
                   405 
                 
                 First stabilization rib (for stabilizing storage containers in Y direction) 
               
               
                 
                   406 
                 
                 Second stabilization rib (for stabilizing storage containers in X direction) 
               
               
                 
                   407 
                 
                 Bracket (for fastening support plate to second stabilization frame) 
               
               
                 
                   408 
                 
                 Rail system 
               
               
                   408 ′ 
                 Coupling rail system 
               
               
                 
                   409 
                 
                 Guiding structure (for hole) 
               
               
                 
                   410 
                 
                 A first set of parallel rails 
               
               
                 
                   411 
                 
                 A second set of parallel rails 
               
               
                 
                   415 
                 
                 Grid opening 
               
               
                 
                   422 
                 
                 Grid cell 
               
               
                 
                   430 
                 
                 Tower 
               
               
                 
                   431 
                 
                 Vertical pillar 
               
               
                 
                   432 
                 
                 Rod 
               
               
                 
                   433 
                 
                 Vertical plate 
               
               
                 
                   434 
                 
                 Container support wheel 
               
               
                 
                   435 
                 
                 Tower support 
               
               
                 
                   436 
                 
                 Port column / chute 
               
               
                 
                   437 
                 
                 Access station 
               
               
                 
                   440 
                 
                 Floor 
               
               
                 
                   500 
                 
                 Control system 
               
               
                 
                   700 
                 
                 Support displacement device / linear actuator 
               
               
                 
                   701 
                 
                 Electric motor 
               
               
                 
                   702 
                 
                 Shaft / threaded shaft 
               
               
                 
                   703 
                 
                 Slider 
               
               
                 
                   704 
                 
                 Linear actuator support 
               
               
                 
                   705 
                 
                 Stopper 
               
               
                 X 
                 First direction 
               
               
                 Y 
                 Second direction 
               
               
                 Z 
                 Third direction 
               
               
                 Prs 
                 Horizontal plane 
               
               
                 W f 
 
                 Width of storage container 
               
               
                 L f 
 
                 Length of storage container 
               
               
                 H f 
 
                 Height of storage container 
               
               
                 Vrl 
                 Offset between lower edge of rail system and lower edge of first container supporting framework 
               
               
                 ΔdV 
                 Offsets between lower edges of container supporting frameworks below the first container framework